Leg length discrepancy and osteoarthritis in the knee, hip and lumbar spine

PubMed Central

Murray, Kelvin J.; Azari, Michael F.

2015-01-01

Osteoarthritis (OA) is an extremely common condition that creates substantial personal and health care costs. An important recognised risk factor for OA is excessive or abnormal mechanical joint loading. Leg length discrepancy (LLD) is a common condition that results in uneven and excessive loading of not only knee joints but also hip joints and lumbar motion segments. Accurate imaging methods of LLD have made it possible to study the biomechanical effects of mild LLD (LLD of 20mm or less). This review examines the accuracy of these methods compared to clinical LLD measurements. It then examines the association between LLD and OA of the joints of the lower extremity. More importantly, it addresses the largely neglected association between LLD and degeneration of lumbar motion segments and the patterns of biomechanical changes that accompany LLD. We propose that mild LLD may be an important instigator or contributor to OA of the hip and lumbar spine, and that it deserves to be rigorously studied in order to decrease OA’s burden of disease. PMID:26500356

Minimizing Leg Length Discrepancy After Intramedullary Nailing of Comminuted Femoral Shaft Fractures: A Quality Improvement Initiative Using the Scout Computed Tomography Scanogram.

PubMed

Gheraibeh, Petra; Vaidya, Rahul; Hudson, Ian; Meehan, Robert; Tonnos, Frederick; Sethi, Anil

2018-05-01

To prevent leg length discrepancy (LLD) after locked femoral nailing in patients with comminuted femoral shaft fractures. Prospective consecutive case series aimed at quality improvement. Level 1 Trauma Center PATIENTS:: Ninety-eight consecutive patients with a comminuted femoral shaft fracture underwent statically locked intramedullary nailing, with a focused attempt at minimizing LLD during surgery. A computed tomography scanogram of both legs was performed on postoperative day 1 to assess for residual LLD. Patients were offered the option to have LLD >1.5 cm corrected before discharge. LLD >1.5 cm. Twenty-one patients (21.4%) were found to have an LLD >1.5 cm. An LLD >1.5 cm occurred in 10/55 (18%) antegrade nail patients and 11/43 (26%) retrograde nail patients (P = 0.27). No difference was noted based on the mechanism of injury, surgeon training and OTA/AO type B versus C injury. Ninety of 98 patients left with <1.5 cm LLD, 13/21 had a correction all to ≤0.6 cm, and 8 decided to accept the LLD and declined early correction. No patient left the hospital with an LLD >1.5 cm after locked intramedullary nailing for a comminuted femoral shaft fracture without being informed and the option of early correction. We recommend using a full-length computed tomography scanogram after IM nailing of comminuted femur fractures to prevent iatrogenic LLD. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Usefulness of intraoperative radiographs in reducing errors of cup placement and leg length during total hip arthroplasty.

PubMed

Wind, Michael A; Morrison, J Craig; Christie, Michael J

2013-11-01

Traditional methods of component placement during total hip arthroplasty (THA) can lead to errors in cup abduction angle and leg length. Intraoperative radiographs were used to assess and correct errors during surgery in a consecutive series of 278 THAs performed by a single surgeon. After exclusions, 262 cases were available for cup abduction angle assessment and 224 for leg length discrepancy (LLD) assessment. Components were initially placed in a position determined as appropriate by the surgeon. Intraoperative radiographs were taken and appropriate corrections made. Postoperative radiographs were assessed at 6 weeks. Mean abduction angle on intraoperative radiographs was 39.6°±5.9° versus 38.6°±4.1° on postoperative radiographs. Thirty-eight cups were outside the target abduction range on intraoperative radiographs versus 4 on postoperative radiographs. Mean LLD was 3.7 mm ± 3.6 mm on intraoperative radiographs and 2.5 mm ± 2.7 mm on postoperative radiographs. Use of intraoperative radiographs is a valid, useful technique for minimizing errors in THA.

Strategies for Managing Massive Defects of the Foot in High-Energy Combat Injuries of the Lower Extremity

DTIC Science & Technology

2010-01-01

infection, or avascular necrosis is extremely difficult. Tibiocalcaneal fusion typically leaves a patient with a leg length discrepancy unless large bone...fractures. J Orthop Trauma 2004;18(5):265–70. 37. Dennison MG, Pool RD, Simonis RB, et al. Tibiocalcaneal fusion for avascular necrosis of the talus

Leg lengthening and femoral-offset reduction after total hip arthroplasty: where is the problem - stem or cup positioning?

PubMed

Al-Amiry, Bariq; Mahmood, Sarwar; Krupic, Ferid; Sayed-Noor, Arkan

2017-09-01

Background Restoration of femoral offset (FO) and leg length is an important goal in total hip arthroplasty (THA) as it improves functional outcome. Purpose To analyze whether the problem of postoperative leg lengthening and FO reduction is related to the femoral stem or acetabular cup positioning or both. Material and Methods Between September 2010 and April 2013, 172 patients with unilateral primary osteoarthritis treated with THA were included. Postoperative leg-length discrepancy (LLD) and global FO (summation of cup and FO) were measured by two observers using a standardized protocol for evaluation of antero-posterior plain hip radiographs. Patients with postoperative leg lengthening ≥10 mm (n = 41) or with reduced global FO >5 mm (n = 58) were further studied by comparing the stem and cup length of the operated side with the contralateral side in the lengthening group, and by comparing the stem and cup offset of the operated side with the contralateral side in the FO reduction group. We evaluated also the inter-observer and intra-observer reliability of the radiological measurements. Results Both observers found that leg lengthening was related to the stem positioning while FO reduction was related to the positioning of both the femoral stem and acetabular cup. Both inter-observer reliability and intra-observer reproducibility were moderate to excellent (intra-class correlation co-efficient, ICC ≥0.69). Conclusion Post THA leg lengthening was mainly caused by improper femoral stem positioning while global FO reduction resulted from improper positioning of both the femoral stem and the acetabular cup.

Should congruence between intra- and interspecific ecomorphological relationships be expected? A case study with the great tit, Parus major

PubMed Central

Moreno, E.; Barbosa, A.; Carrascal, L. M.

1997-01-01

We studied the relationship between leg morphology and posture while feeding in a population of great tits (Parus major) under controlled conditions to investigate to what extent morphology and ecology are linked at the individual level. From predictions generated at the interspecific level within the genus Parus (Moreno and Carrascal 1993), we tested whether intra- and interspecific ecomorphological relationships are consistent. Within our population, neither leg bone lengths nor leg muscle morphology were related to the feeding posture of individuals. However, differences in body weight were correlated with inter-individual differences in time spent hanging. These results demonstrate that the association between intra- and interspecific ecomorphological relationships is not uniform. We argue that, at the intraspecific level, body weight overrides the significance of other traits that have a functional meaning at the interspecific level (i.e. leg segment lengths, muscular morphology), due to isometric variation of morphological traits (muscular and skeletal) with body mass. Thus, the discrepancy between the ecomorphological associations at intra- and interspecific levels is the result of a problem of scale (morphological changes in evolutionary time and isometric variation of morphological traits with body mass in ecological time).

Avascular Necrosis in the Contralateral Hip in Patients With Congenital Femoral Deficiency: A Report of 3 Cases.

PubMed

Brown, Timothy S; Wimberly, Robert L; Birch, John G

2017-01-01

Congenital femoral deficiency is an uncommon clinical entity. We report 3 patients who developed avascular necrosis of the hip in the long (normal) leg during longitudinal observation and/or treatment of congenital femoral deficiency. Patients were identified in limb length discrepancy clinic and their charts were retrospectively reviewed for clinical and radiographic data collection. We describe the occurrence of idiopathic avascular necrosis in the normal limb in patients being followed for limb length discrepancy. Although no conclusion could be drawn about the etiology of the avascular necrosis, we describe a previously undocumented relationship between congenital femoral deficiency and avascular necrosis in the contralateral hip. This occurred in our congenital femoral deficiency population at a rate higher than expected compared with published incidences of avascular necrosis of the hip in children. Level IV-case series.

Trochanteric bursitis after total hip arthroplasty: incidence and evaluation of response to treatment.

PubMed

Farmer, Kevin W; Jones, Lynne C; Brownson, Kirstyn E; Khanuja, Harpal S; Hungerford, Marc W

2010-02-01

We examined the efficacy of corticosteroid injection as treatment for postarthroplasty trochanteric bursitis and the risk factors for failure of nonoperative treatment. There were 32 (4.6%) cases of postsurgical trochanteric bursitis in 689 primary total hip arthroplasties. Of the 25 hips with follow-up, 11 (45%) required multiple injections. Symptoms resolved in 20 (80%) but persisted in 5. We found no statistically significant differences between patients who did and did not develop trochanteric bursitis, or between those who did and did not respond to treatment. There was a trend toward younger age and greater limb-length discrepancy in nonresponders. In conclusion, (1) corticosteroid injection(s) for postoperative trochanteric bursitis is effective; and (2) nonoperative management may be more likely to fail in young patients and those with leg-length discrepancy. 2010 Elsevier Inc. All rights reserved.

Vascular anomalies and the growth of limbs: a review.

PubMed

Enjolras, Odile; Chapot, René; Merland, Jean Jacques

2004-11-01

Growth of the limb in a child can be impaired, with the coexistence of a vascular malformation. In these vascular bone syndromes, altered growth is manifest as overgrowth or hypotrophy. The vascular malformation is usually complex and gets progressively worse with time. The two types of vascular anomalies in limbs, fast-flow and slow-flow, can be associated with limb length discrepancies. The fast-flow vascular malformations together with arteriovenous fistulae are part of Parkes Weber syndrome, characterized by congenital red cutaneous staining, hypertrophy in girth and increasing of limb length, lymphedema, increasing skin alterations due to a distal vascular steal, and pain, all of which develop during childhood. Treatment is generally conservative. An affected lower extremity can be complicated by pelvic tilting and scoliosis because leg length discrepancy may reach 10 cm. To avoid such a course, stapling epiphysiodesis of the knee cartilages is often performed, but this orthopedic procedure may augment the worsening of the arterial venous malformation in the limb. Therefore, less aggressive orthopedic management is preferable. Slow-flow vascular anomalies associated with limb growth alteration include (1) a diffuse capillary malformation (port-wine stain) with congenital hypertrophy of the involved extremity which is non-progressive; (2) purely venous malformations invading skin, muscles and joints, with pain, functional impairment, a chronic localized intravascular coagulopathy requiring distinctive management, and usually a slight undergrowth of the affected extremity and progressing amyotrophy; (3) the triad of a port-wine stain, anomalous veins and overgrowth of the limb, often known as Klippel-Trenaunay syndrome, which requires orthopedic management to decide the optimal timing for epiphysiodesis (i.e. when leg length discrepancy is >2.5 cm). Varicose veins are sometimes surgically removed after ultrasonographic and Doppler evaluation has confirmed a normal deep venous system. Capillary malformations can be effectively treated with pulsed dye laser, but results are usually poor in distal extremities.

The influence of the choice of closing wedge angle on leg length discrepancy after proximal femoral varus osteotomy.

PubMed

Segaren, N; Abdul-Jabar, H B; Hashemi-Nejad, A

2014-08-01

Proximal femoral varus osteotomy improves the biomechanics of the hip and can stimulate normal acetabular development in a dysplastic hip. Medial closing wedge osteotomy remains the most popular technique, but is associated with shortening of the ipsilateral femur. We produced a trigonometric formula which may be used pre-operatively to predict the resultant leg length discrepancy (LLD). We retrospectively examined the influence of the choice of angle in a closing wedge femoral osteotomy on LLD in 120 patients (135 osteotomies, 53% male, mean age six years, (3 to 21), 96% caucasian) over a 15-year period (1998 to 2013). A total of 16 of these patients were excluded due to under or over varus correction. The patients were divided into three age groups: paediatric (< 10 years), adolescent (10 to 16 years) and adult (> 16 years). When using the same saw blades as in this series, the results indicated that for each 10° of angle of resection the resultant LLD equates approximately to multiples of 4 mm, 8 mm and 12 mm in the three age groups, respectively. Statistical testing of the 59 patients who had a complete set of pre- and post-operative standing long leg radiographs, revealed a Pearson's correlation coefficient for predicted versus radiologically observed shortening when using a wedge of either 10° or 20° of 0.93 (p < 0.001). The 95% limits of agreement from the Bland-Altman analysis for this subgroup were -3.5 mm to +3.3 mm. It has been accepted that a 10 mm discrepancy is clinically acceptable. This study identified a geometric model that provided satisfactory accuracy when using specific saw blades of known thicknesses for this formula to be used in clinical practice. ©2014 The British Editorial Society of Bone & Joint Surgery.

Negligence claims in UK total hip arthroplasty: a series of 167 consecutive cases.

PubMed

Whittingham-Jones, Paul; Williams, D; Raja, S; Bridle, S; Bircher, M

2012-01-01

A review of negligence reports, detailing 227 complaints from the practices of two orthopedic surgeons, was undertaken. There were demonstrable differences in the number of complaints over leg-length discrepancy; femoral fracture and cup malposition when cemented versus uncemented implants were compared. Surgeons must appreciate the less forgiving nature of uncemented hip implants and the importance of preoperative planning particularly in the presence of abnormal anatomy.

Atrophic femoral nonunion with bone loss: treatment with monorail transport: a case report.

PubMed

Gay, David M; Voss, Frank R

2004-08-01

Nonunions are an uncommon outcome of femoral fractures. Atrophic nonunions with a leg length discrepancy secondary to bone loss are often the most difficult to treat, and the treatment options are limited. We present a case that uses concomitant monolateral external fixation and intramedullary nailing to heal a nonunion and perform a simultaneous 7-cm lengthening procedure in a 33-year-old female.

Comparison of submuscular and open plating of pediatric femur fractures: a retrospective review.

PubMed

Abbott, Matthew D; Loder, Randall T; Anglen, Jeffrey O

2013-01-01

Plate osteosynthesis is an accepted method of treatment of pediatric femur fractures. Historically, open plating has been used. Submuscular bridge plating has gained recent popularity due to the theoretical advantages of decreased operative time, decreased blood loss, and decreased risk for infection. The purpose of this study was to compare submuscular bridge plating to open plating of pediatric femur fractures. We retrospectively reviewed 79 patients (80 treated femur fractures) between 1999 and 2011 that underwent either open plating (58 femur fractures) or submuscular bridge plating (22 femur fractures). The outcome measures evaluated were operative time, estimated blood loss, malunion, leg length discrepancy, time to union, infection, unplanned return to the operating room, and length of hospital stay after surgery. Among our outcome measures, there was no difference between the 2 groups in terms of operative time, leg length discrepancy, time to union, infection, or length of hospital stay after surgery. There was greater estimated blood loss in the open plating group (P≤0.0001) and greater rotational asymmetry in the submuscular bridge plating group (P=0.005). There was a trend of increased unplanned return to the operating room in the open plating group (5/58 vs. 0/22) although not statistically significant (P=0.32). Submuscular bridge plating and open plating seem to be equally viable options for the management of pediatric diaphyseal femur fractures. In this study, open plating had an increase in estimated blood loss and a trend of more unplanned returns to the operating room, whereas submuscular bridge plating had an increase in asymptomatic rotational asymmetry. Further larger, prospective, randomized studies are necessary to further evaluate these operative techniques. Therapeutic Level III.

Lawsuits After Primary and Revision Total Hip Arthroplasties: A Malpractice Claims Analysis.

PubMed

Patterson, Diana C; Grelsamer, Ronald P; Bronson, Michael J; Moucha, Calin S

2017-10-01

As the prevalence of total hip arthroplasty (THA) expands, so too will complications and patient dissatisfaction. The goal of this study was to identify the common etiologies of malpractice suits and costs of claims after primary and revision THAs. Analysis of 115 malpractice claims filed for alleged neglectful primary and revision THA surgeries by orthopedic surgeons insured by a large New York state malpractice carrier between 1983 and 2011. The incidence of malpractice claims filed for negligent THA procedures is only 0.15% per year in our population. In primary cases, nerve injury ("foot drop") was the most frequent allegation with 27 claims. Negligent surgery causing dislocation was alleged in 18 and leg length discrepancy in 14. Medical complications were also reported, including 3 thromboembolic events and 6 deaths. In revision cases, dislocation and infection were the most common source of suits. The average indemnity payment was $386,153 and the largest single settlement was $4.1 million for an arterial injury resulting in amputation after a primary hip replacement. The average litigation cost to the insurer was $61,833. Nerve injury, dislocation, and leg length discrepancy are the most common reason for malpractice after primary THA. Orthopedic surgeons should continue to focus on minimizing the occurrence of these complications while adequately incorporating details about the risks and limitations of surgery into their preoperative education. Copyright © 2017 Elsevier Inc. All rights reserved.

[A method to avoid lengthening lower limbs after total hip arthroplasty in patients with congenital short femoral neck].

PubMed

Chen, Tao; Shang, Xifu; He, Rui; Hu, Fei; Ge, Chang

2012-03-01

To investigate the method to avoid lengthening lower limbs after total hip arthroplasty in patients with congenital short femoral neck. The clinical data were analyzed retrospectively from 38 patients undergoing unilateral total hip arthroplasty between April 2005 and December 2010. There were 26 males and 12 females, aged 45-78 years (mean, 62.3 years). Among these cases, there were 11 cases of avascular necrosis of the femoral head, 17 cases of hip osteoarthritis, and 10 cases of femoral neck fracture. Before operation, 29 cases had leg length discrepancy; and the shortened length of the legs was 10-24 mm with an average of 14.5 mm by clinical measurement, and was 11-25 mm with an average of 14.7 mm by X-ray film measurement. The Harris score before operation was 44.0 +/- 3.6. At 1 day after operation, 3 cases had legs lengthening by clinical and X-ray film measurement; limb length difference less than 10 mm was regarded as equal limb length in the other 35 patients (92.1%). All incisions healed by first intention, and no complication of infection or lower limb deep venous thrombosis occurred. In 3 patients who had legs lengthening, 1 patient had abnormal gait and slight limping after increasing heel pad because the lower limb was lengthened by 16 mm, and 2 patients had slight limping. The other patients could walk normally and achieved pain relief of hip. Thirty-six patients were followed up 12-68 months (mean, 43.8 months). The Harris score was 86.7 +/- 2.3 after 6 months, showing significant difference (t = 3.260, P = 0.031) when compared with that before operation. The X-ray films showed no prosthetic loosening or subsidence. For patients with congenital short femoral neck during total hip arthroplasty, the surgeons should pay attention to osteotomy plane determination, limb length measurement, and use of the prosthesis with collar to avoid the lengthening lower limbs.

Reconstruction with distraction osteogenesis for juxta-articular nonunions with bone loss.

PubMed

Kabata, Tamon; Tsuchiya, Hiroyuki; Sakurakichi, Keisuke; Yamashiro, Teruhisa; Watanabe, Koji; Tomita, Kasuro

2005-06-01

Nonunions of a juxta-articular lesion with bone loss, which represent a challenging therapeutic problem, were treated using external fixation and distraction osteogenesis. Seven juxta-articular nonunions (five septic and two aseptic) were treated. The location of the nonunion was the distal femur in four patients, the proximal tibia in one patient, and the distal tibia in two patients. All of them were located within 5 cm from the affected joints. Preoperative limb shortening was present in six cases, averaging 2.9 cm (range, 1-7 cm). The reconstructive procedure consisted of refreshment of the nonunion site, deformity correction, stabilization by external fixation, and lengthening to eliminate leg length discrepancy or to fill the defect. Shortening-distraction was applied to six patients and bone transport to one patient for reconstruction. Intramedullary nailing to reduce the duration of external fixation was simultaneously performed in two cases. All the patients had at least 1 year of follow-up evaluation. Osseous union without angular deformity or leg length discrepancy greater than 1 cm was achieved in all patients. The mean amount of lengthening was 5.8 cm (range, 2.2-10.0 cm). The mean external fixation period was 219 days (range, 98-317 days), and the mean external fixation index was 34.4 days/cm (range, 24.5-47.6 days/cm). All patients reported excellent pain reduction. There were no recurrences of infection in five patients with prior history of osteomyelitis. The functional results were categorized as excellent in two, good in three, and fair in two. Despite the length of postoperative external fixation, distraction osteogenesis can be a valuable alternative for the treatment of juxta-articular nonunions.

Minimally invasive locked plating of distal tibia fractures is safe and effective.

PubMed

Ronga, Mario; Longo, Umile Giuseppe; Maffulli, Nicola

2010-04-01

Distal tibial fractures are difficult to manage. Limited soft tissue and poor vascularity impose limitations for traditional plating techniques that require large exposures. The nature of the limitations for traditional plating techniques is intrinsic to the large exposure required to approach distal tibia, a bone characterized by limited soft tissue coverage and poor vascularity. The locking plate (LP) is a new device for treatment of fractures. We assessed the bone union rate, deformity, leg-length discrepancy, ankle range of motion, return to preinjury activities, infection, and complication rate in 21 selected patients who underwent minimally invasive osteosynthesis of closed distal tibia fractures with an LP. According to the AO classification, there were 12 Type A, 5 Type B, and 4 Type C fractures. The minimum followup was 2 years (average, 2.8 years; range, 2-4 years). Two patients were lost to followup. Union was achieved in all but one patient by the 24th postoperative week. Four patients had angular deformity less than 7 degrees . No patient had a leg-length discrepancy more than 1.1 cm. Five patients had ankle range of motion less than 20 degrees compared with the contralateral side. Sixteen patients had not returned to their preinjury sporting or leisure activities. Three patients developed a delayed infection. We judge the LP a reasonable device for treating distal tibia fractures. The level of physical activities appears permanently reduced in most patients. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part II, the functional or unloaded leg-length asymmetry

PubMed Central

Knutson, Gary A

2005-01-01

Background Part II of this review examines the functional "short leg" or unloaded leg length alignment asymmetry, including the relationship between an anatomic and functional leg-length inequality. Based on the reviewed evidence, an outline for clinical decision making regarding functional and anatomic leg-length inequality will be provided. Methods Online databases: Medline, CINAHL and Mantis. Plus library searches for the time frame of 1970–2005 were done using the term "leg-length inequality". Results and Discussion The evidence suggests that an unloaded leg-length asymmetry is a different phenomenon than an anatomic leg-length inequality, and may be due to suprapelvic muscle hypertonicity. Anatomic leg-length inequality and unloaded functional or leg-length alignment asymmetry may interact in a loaded (standing) posture, but not in an unloaded (prone/supine) posture. Conclusion The unloaded, functional leg-length alignment asymmetry is a likely phenomenon, although more research regarding reliability of the measurement procedure and validity relative to spinal dysfunction is needed. Functional leg-length alignment asymmetry should be eliminated before any necessary treatment of anatomic LLI. PMID:16080787

Relationship and significance of gait deviations associated with limb length discrepancy: A systematic review.

PubMed

Khamis, Sam; Carmeli, Eli

2017-09-01

Controversy still exists as to the clinical significance of leg length discrepancy (LLD) in spite of the fact that further evidence has been emerging regarding the relationship between several clinical conditions and LLD. The objectives of our study were to review the available research with regard to LLD as a cause of clinically significant gait deviations, to determine if there is a relationship between the magnitude of LLD and the presence of gait deviations and to identify the most common gait deviations associated with LLD. In line with the PRISMA guidelines, a literature search was carried out throughout the Medline, CINAHL and EMBASE databases. Twelve articles met the predetermined inclusion criteria and were included in the review. Quality assessment using the Methodological Index for Non-Randomized Studies (MINORS) scale was completed for all included studies. Two main methodologies were found in 4 studies evaluating gait asymmetry in patients or healthy participants with anatomic LLD and 8 studies evaluating gait deviations while simulating LLD by employing artificial lifts of 1-5cm on healthy subjects. A significant relationship was found between anatomic LLD and gait deviation. Evidence suggests that gait deviations may occur with discrepancies of >1cm, with greater impact seen as the discrepancy increases. Compensatory strategies were found to occur in both the shorter and longer limb, throughout the lower limb. As the discrepancy increases, more compensatory strategies occur. Sagittal plane deviations seem to be the most effective deviations, although, frontal plane compensations also occur in the pelvis, hip and foot. Copyright © 2017 Elsevier B.V. All rights reserved.

Unilateral total hip replacement patients with symptomatic leg length inequality have abnormal hip biomechanics during walking.

PubMed

Li, Junyan; McWilliams, Anthony B; Jin, Zhongmin; Fisher, John; Stone, Martin H; Redmond, Anthony C; Stewart, Todd D

2015-06-01

Symptomatic leg length inequality accounts for 8.7% of total hip replacement related claims made against the UK National Health Service Litigation authority. It has not been established whether symptomatic leg length inequality patients following total hip replacement have abnormal hip kinetics during gait. Hip kinetics in 15 unilateral total hip replacement patients with symptomatic leg length inequality during gait was determined through multibody dynamics and compared to 15 native hip healthy controls and 15 'successful' asymptomatic unilateral total hip replacement patients. More significant differences from normal were found in symptomatic leg length inequality patients than in asymptomatic total hip replacement patients. The leg length inequality patients had altered functions defined by lower gait velocity, reduced stride length, reduced ground reaction force, decreased hip range of motion, reduced hip moment and less dynamic hip force with a 24% lower heel-strike peak, 66% higher mid-stance trough and 37% lower toe-off peak. Greater asymmetry in hip contact force was also observed in leg length inequality patients. These gait adaptions may affect the function of the implant and other healthy joints in symptomatic leg length inequality patients. This study provides important information for the musculoskeletal function and rehabilitation of symptomatic leg length inequality patients. Copyright © 2015. Published by Elsevier Ltd.

Three-stage treatment protocol for recalcitrant distal femoral nonunion.

PubMed

Ma, Ching-Hou; Chiu, Yen-Chun; Tu, Yuan-Kun; Yen, Cheng-Yo; Wu, Chin-Hsien

2017-04-01

In this study, we proposed a three-stage treatment protocol for recalcitrant distal femoral nonunion and aimed to analyze the clinical results. We retrospective reviewed 12 consecutive patients with recalcitrant distal femoral nonunion undergoing our three-stage treatment protocol from January 2010 to December 2014 in our institute. The three-stage treatment protocol comprised debridement of the nonunion site, lengthening to eliminate leg length discrepancy, deformity correction, stabilization with a locked plate, filling of the defect with cement spacer for inducing membrane formation, and bone reconstruction using a cancellous bone autograft (Masquelet technique) or free vascularized fibular bone graft. The bone union time, wound complication, lower limbs alignment, amount of lengthening, knee range of motion, and functional outcomes were evaluated. Osseous union with angular deformity <5° and leg length discrepancy <1 cm were achieved in all the patients. The average amount of lengthening was 5.88 cm (range 3.5-12 cm). Excellent or good outcomes were obtained in 9 patients. Although the current study involved only a small number of patients and the intervention comprised three stages, we believe that such a protocol may be a valuable alternative for the treatment of recalcitrant distal femoral nonunion.

True or apparent leg length discrepancy: which is a better predictor of short-term functional outcomes after total hip arthroplasty?

PubMed

Nakanowatari, Tatsuya; Suzukamo, Yoshimi; Suga, Toshimitsu; Okii, Akira; Fujii, Genji; Izumi, Shin-Ichi

2013-01-01

The associations between leg length discrepancy (LLD) and patient-perceived inequality and functional outcomes after total hip arthroplasty (THA) are unclear in the literature. The aim of this study was to determine the types of LLD after THA and to identify the best predictor of patient-perceived LLD and functional outcome in the short term after THA. We subdivided LLD into true and apparent types and prospectively studied 53 consecutive patients undergoing unilateral primary THA to determine whether there is an association between the type of LLD and functional outcome 2 months after the operation. Apparent LLD was measured by the block test and true LLD was measured by hip radiography. We classified the patients into 4 groups: true, apparent, mixed, and no-LLD groups. The questionnaire included a visual analog scale of pain, the Western Ontario and McMaster Universities Osteoarthritis Index, and patient-perceived inequality. Physical performance was measured using walking speed and the Timed Up and Go test. The apparent and mixed LLD groups had a higher prevalence of patient-perceived inequality than the true and no-LLD groups. The results of physical performance showed that the walking speed of the mixed LLD group and the results of the Timed Up and Go Test of the apparent LLD group were significantly slower than those of the true LLD group. We suggested that the true LLD group may have a weak relationship with functional outcome after THA while the apparent LLD resulting from pelvic obliquity due to hip contracture or scoliosis is correlated with the short-term functional outcome after THA. Apparent LLD can be a better predictor of patient-perceived inequality and physical performance than true LLD.

The effects of real and artificial Leg Length Discrepancy on mechanical work and energy cost during the gait.

PubMed

Assogba, T F; Boulet, S; Detrembleur, C; Mahaudens, P

2018-01-01

The impacts of Leg Length Discrepancy (LLD) on the kinematic and dynamic parameters of walking have been widely discussed. But little is known on total mechanical work and energy cost. These two variables are more representative of the functional impairment undergone by the LLD patients. To assess the changes of the mechanical work and energy cost of walking in subjects with real LLD and to compare their results with healthy subjects in whom the LLD has been simulated. The mechanical work and energy cost data of 60 healthy subjects (speed: 4km/h) with artificial LLD induced by soles (2 and 4cm), 20 patients (speed: 3.75±0.5km/h) with real LLD and 20 matched subjects (speed: 3.75±0.5km/h) were collected. Statistical comparisons between the groups were performed using a t-paired test and ANOVA. Patients with a real LLD showed a significant decrease in mechanical work and energy cost when compared to norms. Patients with real LLD provide a better recovery when compared to subjects with artificial LLD of 2cm, and a decrease of energy cost and higher muscular efficiency (mechanical work/energy cost) when compared to subjects with artificial LLD of 4cm. Our results showed that patients with a real LLD develop compensatory strategies during gait, probably to minimize the displacement of the body center of mass and consequently reduce the amount of energy expenditure useful for their displacement. Moreover, they adopt a better gait strategy compared to the subjects in whom LLD was simulated. Copyright © 2017 Elsevier B.V. All rights reserved.

Femoral Reconstruction Using External Fixation

PubMed Central

Palatnik, Yevgeniy; Rozbruch, S. Robert

2011-01-01

Background. The use of an external fixator for the purpose of distraction osteogenesis has been applied to a wide range of orthopedic problems caused by such diverse etiologies as congenital disease, metabolic conditions, infections, traumatic injuries, and congenital short stature. The purpose of this study was to analyze our experience of utilizing this method in patients undergoing a variety of orthopedic procedures of the femur. Methods. We retrospectively reviewed our experience of using external fixation for femoral reconstruction. Three subgroups were defined based on the primary reconstruction goal lengthening, deformity correction, and repair of nonunion/bone defect. Factors such as leg length discrepancy (LLD), limb alignment, and external fixation time and complications were evaluated for the entire group and the 3 subgroups. Results. There was substantial improvement in the overall LLD, femoral length discrepancy, and limb alignment as measured by mechanical axis deviation (MAD) and lateral distal femoral angle (LDFA) for the entire group as well as the subgroups. Conclusions. The Ilizarov external fixator allows for decreased surgical exposure and preservation of blood supply to bone, avoidance of bone grafting and internal fixation, and simultaneous lengthening and deformity correction, making it a very useful technique for femoral reconstruction. PMID:21991425

A rationale for treating leg length discrepancy using photodynamic therapy

NASA Astrophysics Data System (ADS)

Bisland, Stuart K.; Johnson, Crystal; Diab, Mohammed; Wilson, Brian C.; Burch, Shane

2005-09-01

This study investigates the use of photodynamic therapy (PDT) in regulating bone development with a view to its potential role in treating Juvenile leg length discrepancy (LLD). Transgenic mice expressing the luciferase firefly gene upon activation of a promoter sequence specific to the vascular endothelial growth factor (VEGF) gene were subject to benzoporphyrin derivative monoacid (BPD-MA)-mediated PDT in the right, tibial epiphyseal growth plate at the age of 3 weeks. BPD-MA was administered intracardially (2mg/kg) followed 10 mins later by a laser light (690 +/- 5 nm) at a range of doses (5-27J, 50 mW output) delivered either as a single or repeat regimen (x2-3). Contra-lateral legs served as no-light controls. Further controls included animals that received light treatment in the absence of photosensitizer or no treatment. Mice were imaged for VEGF related bioluminescence (photons/sec/steradian) at t= 0, 24, 48, 72 h and 1-4 weeks post PDT. FaxitronTM x-ray images provided accurate assessment of bone morphometry. Upon sacrifice, the tibia and femur of the treated and untreated limbs were harvested, imaged and measured again and prepared for histology. A number of animals were sacrificed at 24 h post PDT to allow immunohistochemical staining for CD31, VEGF and hypoxia-inducible factor (HIF-1 alpha) within the bone. PDT-treated (10 J, x2) mice displayed enhanced bioluminescence at the treatment site (and ear nick) for up to 4 weeks post treatment while control mice were bioluminescent at the ear-nick site only. Repeat regimens provided greater shortening of the limb than the corresponding single treatment. PDT-treated limbs were shorter by 3-4 mm on average as compared to the contra lateral and light only controls (10 J, x2). Immunohistochemistry confirmed the enhanced expression VEGF and CD31 at 4 weeks post-treatment although no increase in HIF-1α was evident at either 24 h or 4 weeks post PDT treatment. Results confirm the utility of PDT to provide localized effects on bone development that may be applicable to other related skeletal deformities.

Compliant walking appears metabolically advantageous at extreme step lengths.

PubMed

Kim, Jaehoon; Bertram, John E A

2018-05-19

Humans alter gait in response to unusual gait circumstances to accomplish the task of walking. For instance, subjects spontaneously increase leg compliance at a step length threshold as step length increases. Here we test the hypothesis that this transition occurs based on the level of energy expenditure, where compliant walking becomes less energetically demanding at long step lengths. To map and compare the metabolic cost of normal and compliant walking as step length increases. 10 healthy individuals walked on a treadmill using progressively increasing step lengths (100%, 120%, 140% and 160% of preferred step length), in both normal and compliant leg walking as energy expenditure was recorded via indirect calorimetry. Leg compliance was controlled by lowering the center-of-mass trajectory during stance, forcing the leg to flex and extend as the body moved over the foot contact. For normal step lengths, compliant leg walking was more costly than normal walking gait, but compliant leg walking energetic cost did not increase as rapidly for longer step lengths. This led to an intersection between normal and compliant walking cost curves at 114% relative step length (regression analysis; r 2  = 0.92 for normal walking; r 2  = 0.65 for compliant walking). Compliant leg walking is less energetically demanding at longer step lengths where a spontaneous shift to compliant walking has been observed, suggesting the human motor control system is sensitive to energetic requirements and will employ alternate movement patterns if advantageous strategies are available. The transition could be attributed to the interplay between (i) leg work controlling body travel during single stance and (ii) leg work to control energy loss in the step-to-step transition. Compliant leg walking requires more stance leg work at normal step lengths, but involves less energy loss at the step-to-step transition for very long steps. Copyright © 2018 Elsevier B.V. All rights reserved.

Premature femoral neck physeal closure in Perthes' disease.

PubMed

Bowen, J R; Schreiber, F C; Foster, B K; Wein, B K

1982-01-01

One hundred premature femoral neck physeal closures in 430 hips with Perthes' disease have occurred in two patterns central and lateral. Abnormal physeal growth can be demonstrated early by a narrowed physeal plate with overlying avascular epiphysis and marked metaphyseal reaction below. Subsequently, a bony bridge forms between the metaphysis and epiphysis. If the physeal closure is central, the mature hip will have a short femoral neck, a relatively round femoral head, a trochanter that has overgrown the femoral head, a short leg, and a mildly deformed acetabulum. If the physeal closure is lateral, the mature hip will have a femoral head that is externally tilted as the medial neck lengthens and the lateral neck remains short, a trochanter that has overgrown the femoral head, an oval femoral head, a short leg, and a deformed acetabulum. A physeal arrest is a contraindication for a varus osteotomy because it accentuates the deformity, especially in the greater trochanter. The leg-length discrepancy may be treated by epiphysiodesis of the contralateral femur, when necessary, and the abductor muscle insufficiency may be treated by an exercise program or distal and lateral transfer of the greater trochanter.

Lower limb alignment characteristics are not associated with running injuries in runners: Prospective cohort study.

PubMed

Hespanhol Junior, Luiz Carlos; de Carvalho, Aline Carla Araújo; Costa, Leonardo Oliveira Pena; Lopes, Alexandre Dias

2016-11-01

There is conflicting evidence on the association between lower limb alignment characteristics and the incidence of running-related injury (RRI). Therefore, the primary aim of this study was to investigate the association between lower limb alignment characteristics and the incidence proportion of RRI in a convenience sample of recreational runners. A total of 89 recreational runners were included in this prospective cohort study. These participants had been running for at least six months and were injury-free at baseline. Lower limb alignment measurements were conducted in order to calculate lower limb discrepancy, Q-angle, subtalar angle and plantar index. All participants also answered a baseline and biweekly online surveys about their running routine, history of RRI and newly developed RRI over a period of 12 weeks. The prevalence of previous RRI and the 12-week incidence proportion of new RRI were calculated. Logistic regression analysis was performed to estimate the association between lower limb length discrepancy, Q-angle, subtalar angle and plantar ach index with the incidence proportion of RRI. The prevalence of previous RRI was 55.1% (n = 49). The 12-week incidence proportion of new RRI was 27.0% (n = 24). Muscle injuries and tendinopathies were the main types of RRI identified. The lower leg and the knee were the main anatomical regions affected. We did not find significant associations between lower limb length discrepancy, Q-angle, subtalar angle and plantar arch index and injury occurrence.

Pre-operative digital templating in cemented hip hemiarthroplasty for neck of femur fractures.

PubMed

Kwok, Iris H Y; Pallett, Scott J C; Massa, Edward; Cundall-Curry, Duncan; Loeffler, Mark D

2016-03-01

Pre-operative digital templating allows the surgeon to foresee any anatomical anomalies which may lead to intra-operative problems, and anticipate appropriate instruments and implants required during surgery. Although its role is well-established in successful elective total hip arthroplasty, little work has been done on its use in hip hemiarthroplasty in neck of femur fractures. We describe our initial experience of digital templating in 40 consecutive patients who have undergone cemented hip hemiarthroplasty, assessing templating accuracy between templated implant sizes to actual implant sizes. 81% of implanted heads were templated to within two head sizes, and 89% of implanted stems were templated to within two sizes. Although there was a moderately strong correlation of 0.52 between templated and actual head sizes, this correlation was not demonstrated in femoral stem sizes. Mean leg length discrepancy was -2.5mm (S.D. 8.5), and the mean difference in femoral offset between the operated and non-operated hip was -1mm (S.D. 4.4). Digital templating is a useful adjunct to the surgeon in pre-operative planning of hip hemiarthroplasty in the restoration of leg length and femoral offset. However, its accuracy is inferior to that of elective total hip arthroplasty. Copyright © 2016 Elsevier Ltd. All rights reserved.

Knee arthrodesis with a press-fit modular intramedullary nail without bone-on-bone fusion after an infected revision TKA.

PubMed

Iacono, Francesco; Bruni, Danilo; Lo Presti, Mirco; Raspugli, Giovanni; Bondi, Alice; Sharma, Bharat; Marcacci, Maurilio

2012-10-01

Knee arthrodesis can be an effective treatment after an infected revision Total Knee Arthroplasty (TKA). The main hypothesis of this study is that a two-stage arthrodesis of the knee using a press-fit, modular intramedullary nail and antibiotic loaded cement, to fill the residual gap between the bone surfaces, prevents an excessive limb shortening, providing satisfactory clinical and functional results even without direct bone-on-bone fusion. The study included 22 patients who underwent knee arthrodesis between 2004 and 2009 because of recurrent infection following revision-TKA (R-TKA). Clinical and functional evaluations were performed using the Visual Analogue Scale (VAS) and the Lequesne Algofunctional Score. A postoperative clinical and radiographical evaluation of the residual limb-length discrepancy was conducted by three independent observers. VAS and LAS results showed a significant improvement with respect to the preoperative condition. The mean leg length discrepancy was less than 1cm. There were three recurrent infections that needed further surgical treatment. This study demonstrated that reinfection after Revision of total knee Arthroplasty can be effectively treated with arthrodesis using a modular intramedullary nail, along with an antibiotic loaded cement spacer and that satisfactory results can be obtained without direct bone-on-bone fusion. Published by Elsevier B.V.

Physeal-Specific MRI Analysis of Growth Plate Disturbance Following All-Inside Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: Does a Physeal-Sparing Technique Offer any Advantage?

PubMed Central

Nawabi, Danyal H.; Jones, Kristofer J.; Lurie, Brett; Potter, Hollis G.; Green, Daniel W.; Cordasco, Frank A.

2013-01-01

Objectives: The decision to perform anterior cruciate ligament (ACL) reconstruction in skeletally immature patients carries a risk of growth disturbance due to iatrogenic physeal injury. Multiple physeal-sparing techniques have been described but none, to our knowledge combine the benefits of an anatomic reconstruction and socket fixation, without violation of either the femoral or tibial physis at any stage of the procedure. The purpose of this study was to compare the incidence and calculate the area of post-operative physeal disturbances, using a physeal-sensitive magnetic resonance imaging (MRI) sequence*, between all-epiphyseal (AE) and partial transphyseal (PTP) ACL reconstructions in a cohort of skeletally-immature patients. Methods: Twenty-one skeletally immature patients with a mean chronologic age of 12.7 years (range 10 to 16) undergoing all-inside ACL reconstruction were prospectively followed. Fourteen patients had an all-epiphyseal (AE) ACL reconstruction and 7 patients had a partial transphyseal (PTP) ACL reconstruction, which spared the femoral physis but crossed the tibial physis. Hamstring autograft was used in all cases. At a mean of 11.6 months follow-up, all patients were assessed for focal physeal disturbance and graft survival using a three-dimensional (3D) fat suppressed spoiled gradient-recalled echo (SPGR) MRI sequence. Angular deformity and leg length discrepancy were evaluated on full-length standing radiographs. The International Knee Documentation Committee (IKDC) subjective score and Lysholm knee score were also documented. Results: The tibial physis was violated in 13/14 patients in the AE group and all patients in the PTP group. The mean area of post-operative tibial physeal disturbance (± SD) was 42.4 ± 38.6 mm2 (mean 1.7% of total physeal area) in the AE group compared to 216.7 ± 129.1 mm2 (mean 7.3% of total physeal area) in the PTP group (p = 0.003). The femoral physis was violated in one case in both groups resulting in a mean physeal disturbance of 1.5% of the total distal femoral physeal area. No cases of fracture, articular surface violation or avascular necrosis were noted on MRI in either group. Short-term graft survival was 100% amongst the entire cohort. There were no cases of angular deformity in either group with a mean side-side difference in the lateral distal femoral angle of 1.11° ± 1.02° in the AE group and 0.72° ± 0.65° in the PTP group (p = 0.23). No significant leg-length discrepancies were measured in either group. The mean IKDC and Lysholm scores (± SD) were 93.3 ± 5.9 and 97.8 ± 3.8 respectively in the AE group and 87.7 ± 3.5 and 96 ± 5.2 respectively in the PTP group. Conclusion: All-epiphyseal ACL reconstruction caused significantly less focal physeal disturbance than PTP ACL reconstruction, as determined by a 3D physeal-sensitive MRI sequence. Neither technique however resulted in angular deformity or leg-length discrepancy at early follow-up. Both all-inside ACL reconstruction techniques used in this study are safe and effective at early follow-up in skeletally immature patients. Further longitudinal study of this cohort is required to determine any potential advantages of a purely physeal-sparing technique.

Tibial lengthening using a humeral intramedullary nail combined with a single-plane external fixator for leg discrepancy in sequelae of poliomyelitis.

PubMed

Chen, Daoyun; Chen, Jianmin; Liu, Fanggang; Jiang, Yao

2011-03-01

The sequelae of poliomyelitis are the common causes of leg discrepancy. Tibial lengthening is an effective way to solve this problem but it is associated with a high rate of complications. In this study, we combined the use of humeral nail and external fixator in tibial lengthening with the purpose of reducing lengthening complications. Compared with the cases lengthened by a single-plane external fixator alone, this combined strategy was found to be beneficial in maintaining the tibial alignment. Therefore, it can be recommended as a good technique for tibial lengthening in patients with sequelae of poliomyelitis.

Pelvic bone asymmetry in 323 study participants receiving abdominal CT scans.

PubMed

Badii, Maziar; Shin, Sonya; Torreggiani, William C; Jankovic, Bojana; Gustafson, Paul; Munk, Peter L; Esdaile, John M

2003-06-15

Retrospective review of all CT scans of pelvis and abdomen performed at our institution in October and November 2000. To determine the prevalence and extent of radiographic pelvic asymmetry in a population of patients not preselected for having low back pain. Pelvic asymmetry refers to asymmetric positioning of landmarks on the two sides of the pelvis and may have a structural or functional etiology. Pelvic asymmetry can be associated with the presence of true leg length discrepancy, lead to false diagnosis or inaccurate measurement of leg length discrepancy, or itself be independently associated with back pain. Although the prevalence of pelvic asymmetry has been reported in patients with back pain to be 24-91%, its prevalence in the general population is not known. A total of 323 consecutive CT scans of the pelvis/abdomen were assessed for pelvic asymmetry by one of three examiners. Pelvic asymmetry was defined as an unequal distance from the iliac crests to the acetabuli bilaterally, measured on the anteroposterior scout view of the CT scan. Measurements made on 30 randomly selected scans by the three examiners were used to assess interrater reliability of the measurement method. Pelvic asymmetry ranged in magnitude from -11 mm to 7 mm [right pelvis (mm) - left pelvis (mm)]. Pelvic asymmetry was >5 mm in 17 of 323 (5.3%) and >10 mm in 2 of 323 (0.6%) of the subjects; 172 of 323 (53.3%) had a smaller right hemipelvis (mean asymmetry = -3.0 mm). A total of 95 of 323 (29.4%) had a smaller left hemipelvis (mean asymmetry = 2.1 mm). The intraclass correlation coefficient [ICC(2,1)] between the three observers was high (0.91). Pelvic asymmetry of >5 mm was uncommon, with a prevalence of approximately 5% in the population studied. CT scanography was found to be a practical and reliable method for the assessment of suspected pelvic asymmetry.

Radiographic cup position following posterior and lateral approach to total hip arthroplasty. An explorative randomized controlled trial.

PubMed

Kruse, Christine; Rosenlund, Signe; Broeng, Leif; Overgaard, Søren

2018-01-01

The two most common surgical approaches to total hip arthroplasty are the posterior approach and lateral approach. The surgical approach may influence cup positioning and restoration of the offset, which may affect the biomechanical properties of the hip joint. The primary aim was to compare cup position between posterior approach and lateral approach. Secondary aims were to compare femoral offset, abductor moment arm and leg length discrepancy between the two approaches. Eighty patients with primary hip osteoarthritis were included in a randomized controlled trial and assigned to total hip arthroplasty using posterior approach or lateral approach. Postoperative radiographs from 38 patients in each group were included in this study for measurement of cup anteversion and inclination. Femoral offset, cup offset, total offset, abductor moment arm and leg length discrepancy were measured on preoperative and postoperative radiographs in 28 patients in each group. We found that mean anteversion was 5° larger in the posterior approach group (95% CI, -8.1 to -1.4; p = 0.006), while mean inclination was 5° less steep (95% CI, 2.7 to 7.2; p<0.001) compared with the lateral approach group. The posterior approach group had a larger mean femoral offset of 4.3mm (95% CI, -7.4 to -1.3, p = 0.006), mean total offset of 6.3mm (95% CI, -9.6 to -3; p<0.001) and mean abductor moment arm of 4.8mm (95% CI, -7.6 to -1.9; p = 0.001) compared with the lateral approach group. We found a larger cup anteversion but less steep cup inclination in the posterior approach group compared with the lateral approach group. Femoral offset and abductor moment arm were restored after total hip arthroplasty using lateral approach but significantly increased when using posterior approach.

Components of height and blood pressure in childhood

PubMed Central

Regnault, Nolwenn; Kleinman, Ken P; Rifas-Shiman, Sheryl L; Langenberg, Claudia; Lipshultz, Steven E; Gillman, Matthew W

2014-01-01

Background In children being taller is associated with higher blood pressure (BP), but few studies have divided height into its components: trunk and leg length. We examined the associations of total height, trunk length and leg length with systolic BP (SBP), diastolic BP (DBP) and pulse pressure (PP) at early childhood and mid-childhood visits, as well as change between the two visits. Methods We obtained five measures of SBP and DBP at the early childhood visit (N = 1153, follow-up rate = 54%) and at the mid-childhood visit (N = 1086, follow-up rate = 51%) respectively, in Project Viva, a US cohort study. We measured total height and sitting height (a measure of trunk length that includes head and neck) and calculated leg length as the difference between the two. Using mixed models, we adjusted the cross-sectional analyses for leg length when trunk length was the exposure of interest, and vice versa. We also adjusted for maternal race/ethnicity, child age, sex, overall adiposity and BP measurement conditions. Results At the mid-childhood visit, total height was positively associated with SBP [0.34 (0.24; 0.45) mmHg/cm] but not with DBP [0.07 (−0.003; 0.15)]. In models examining trunk and leg length separately, each was positively associated with SBP [0.72 (0.52; 0.92) and 0.33 (0.16; 0.49) respectively]. In a fully adjusted model with both leg and trunk length, only trunk length remained associated with BP. For a given leg length, a 1-cm increment in trunk length was associated with a 0.63-mmHg (0.42; 0.83) higher SBP and a 0.17-mmHg (0.02; 0.31) higher DBP. For a given trunk length, however, the associations of leg length with SBP [0.13 (−0.03; 0.30)] and with DBP [0.002 (−0.11; 0.12)] were null. These patterns were similar at the early childhood visit. Conclusions Children with greater trunk lengths have higher BPs, perhaps because of the additional pressure needed to overcome gravity to perfuse the brain. PMID:24413933

Calf restoration with asymmetric fat injection in polio sequelae.

PubMed

Yazar, Memet; Kurt Yazar, Sevgi; Kozanoğlu, Erol

2016-09-01

Many things cause leg asymmetry and sequelae seen after poliomyelitis infections are still a cause of leg deformities. In this study, lipofilling and liposuction combinations are performed on patients with poliomyelitis sequelae. Volume deficiency is not the only leg problem with polio sequelae, leg length is also a problem. For this reason, the length deficiency must be addressed in order to achieve the desired symmetry. The aim of this study is correcting limb asymmetry by a method addressing both limb length deficiency by heel raise and volume deficiency by injection of fat based on corrected limb length. From 2011 through 2013, 10 female patients who had unilateral leg atrophy as a result of paediatric polio infections were included in our study. All of the patients were treated with liposuction and lipofilling combinations. During planning, a ridge was placed under the affected leg in order to equalize the lengths of both legs. The fat injection sites on the affected leg were marked to mimic the unaffected leg. All the patients stated that they were satisfied with the results. Transient hypoesthesia was seen in only one patient, but this was spontaneously resolved six months later. The study results indicate that the asymmetric fat injection procedure can be a good technique to use with patients who have polio sequelae, both with short legs and volume deformities. 4. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Arthrodesis After Infected Revision TKA: Retrospective Comparison of Intramedullary Nailing and External Fixation.

PubMed

Iacono, Francesco; Francesco, Iacono; Raspugli, Giovanni Francesco; Francesco, Raspugli Giovanni; Bruni, Danilo; Danilo, Bruni; Lo Presti, Mirco; Mirco, Lo Presti; Sharma, Bharat; Bharat, Sharma; Akkawi, Ibrahim; Ibrahim, Akkawi; Marcacci, Maurilio; Maurilio, Marcacci

2013-10-01

Infection after revision total knee arthroplasty (TKA) for previous septic TKA can be a challenging problem to treat due to loss of bone stock and soft tissue integrity. In these cases, arthrodesis is a well-recognized salvage procedure. The aim of this retrospective study was to compare the results as described by a Visual Analogue Scale (VAS) and the Lequesne Algofunctional Score (LAS) of knee arthrodeses performed by using either an external fixator (EF) or an intramedullary nail (IM). The study included 34 knee arthrodesis divided in two groups: first group included 12 patients treated with EF and the second group of 22 patients dealt with IM nail. Clinical and functional evaluation was performed using the VAS and the LAS. Full-length radiographs were used to verify limb length discrepancy. VAS and LAS results showed a substantial improvement relative to preoperative condition in both groups. However, the LAS was significantly better in the IM nail group. The mean leg length discrepancy was significantly greater (4.5 cm) in the first group than in the second one (0.8 cm). No recurrence of infection was observed in the EF group while there were three recurrent infections in the IM nail group. Our study supported the existing literature and found that reinfection after revision TKA can be effectively treated with arthrodesis. In presence of massive bone loss, we recommend arthrodesis with IM nail used as an endoprosthesis, without bone-on-bone fusion, to produce a stable and painless knee, while preserving the limb length. Use of an IM nail allowed us to get a better functional result than EF.

Staged lengthening arthroplasty for pediatric osteosarcoma around the knee.

PubMed

Kong, Chang-Bae; Lee, Soo-Yong; Jeon, Dae-Geun

2010-06-01

Orthopaedic oncologists often must address leg-length discrepancy after resection of tumors in growing patients with osteosarcoma. There are various alternatives to address this problem. We describe a three-stage procedure: (1) temporary arthrodesis, (2) lengthening by Ilizarov apparatus, and (3) tumor prosthesis. We asked (1) to what extent are affected limbs actually lengthened; (2) how many of the patients who undergo a lengthening procedure eventually achieve joint arthroplasty; and (3) can the three-stage procedure give patients a functioning joint with equalization of limb length? We reviewed 56 patients (younger than 14 years) with osteosarcoma who had staged lengthening arthroplasty between 1991 and 2004. Thirty-five of the 56 patients (63%) underwent soft tissue lengthening, and of these 35, 28 (50% of the original group of 56) had implantation of a mobile joint. Three of the 28 prostheses were later removed owing to infection after arthroplasty. The overall average length gained was 7.8 cm (range, 4-14 cm), and 25 (71%) of the 35 patients had a mobile joint at final followup. The average Musculoskeletal Tumor Society functional score was 23.2 (range, 15-28) and limb-length discrepancy at final followup was 2.6 cm (range, 0-6.5 cm). Although most mobile joints had an acceptable ROM (average, 74.2 degrees ; range, 35 degrees -110 degrees ), extension lag was frequent. Our approach is one option for skeletally immature patients, especially in situations where an expandable prosthesis is not available. However, this technique requires multiple stages and would be inappropriate for patients who cannot accept prolonged functional deficit owing to a limited lifespan or other reasons. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Leg length, body proportion, and health: a review with a note on beauty.

PubMed

Bogin, Barry; Varela-Silva, Maria Inês

2010-03-01

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature x 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility.

Leg Length, Body Proportion, and Health: A Review with a Note on Beauty

PubMed Central

Bogin, Barry; Varela-Silva, Maria Inês

2010-01-01

Decomposing stature into its major components is proving to be a useful strategy to assess the antecedents of disease, morbidity and death in adulthood. Human leg length (femur + tibia), sitting height (trunk length + head length) and their proportions, for example, (leg length/stature), or the sitting height ratio (sitting height/stature × 100), among others) are associated with epidemiological risk for overweight (fatness), coronary heart disease, diabetes, liver dysfunction and certain cancers. There is also wide support for the use of relative leg length as an indicator of the quality of the environment for growth during infancy, childhood and the juvenile years of development. Human beings follow a cephalo-caudal gradient of growth, the pattern of growth common to all mammals. A special feature of the human pattern is that between birth and puberty the legs grow relatively faster than other post-cranial body segments. For groups of children and youth, short stature due to relatively short legs (i.e., a high sitting height ratio) is generally a marker of an adverse environment. The development of human body proportions is the product of environmental x genomic interactions, although few if any specific genes are known. The HOXd and the short stature homeobox-containing gene (SHOX) are genomic regions that may be relevant to human body proportions. For example, one of the SHOX related disorders is Turner syndrome. However, research with non-pathological populations indicates that the environment is a more powerful force influencing leg length and body proportions than genes. Leg length and proportion are important in the perception of human beauty, which is often considered a sign of health and fertility. PMID:20617018

Height and relative leg length as indicators of the quality of the environment among Mozambican juveniles and adolescents.

PubMed

Padez, Cristina; Varela-Silva, Maria Inês; Bogin, Barry

2009-01-01

The growth status of Mozambique adolescents was assessed to test the hypothesis that relative leg length is a more sensitive indicator of the quality of the environment than the total height. The sample comprised 690 boys and 727 girls, aged between 9 and 17 years, from Maputo. It is divided between those living in the Centre of Maputo and those living in the slums on the periphery of the city. Height, weight, and sitting height were measured and the sitting height ratio was calculated. The hypothesis that relative leg length is more sensitive than total stature as an indicator of environmental quality is not uniformly confirmed. Overall, mean stature is greater for the centre group than the slum group, but relative leg length as measured by the sitting height ratio does not differ. Compared with African-American references (NHANES II), all centre girls, 9- to 14-year-old slum girls, all slum boys, and the oldest centre boys show relatively shorter legs. These findings show that within the Mozambique sample, relative leg length is not sensitive enough to distinguish the quality of the living environment. Mozambique was a colony of Portugal until 1975. Civil unrest and warfare characterized the late Colonial period and the postindependence period until a peace settlement was concluded in 1992. It is possible that all socioeconomic status groups within the country suffered sufficiently to reduce relative leg length compared with the better-off African-American reference sample. Possible genetic influences on relative leg length are also discussed.

Knee arthrodesis using an intramedullary nail.

PubMed

Crockarell, John R; Mihalko, Marc J

2005-09-01

Fifteen knee arthrodeses using an intramedullary nail were performed in 15 patients. Indications included 11 failed total knee arthroplasties (10 of 11 septic). A retrospective review revealed 100% fusion rate. Complications included 4 cases of painful hardware, 1 trochanteric bursitis, and 1 deep infection. Ten patients were available for assessment at 7 years follow-up. Average leg length discrepancy was 3.7 cm. Anatomic axis averaged 1.3 degrees valgus. Flexion angle averaged 3.5 degrees . Compared with age-matched controls, our patients fared significantly worse in physical functioning, physical role, bodily pain, vitality, and social functioning. Arthrodesis of the knee with an intramedullary nail provides a reliable means of fusion with reasonable alignment. These patients have high rates of pain and diminished functional status.

Youth Baseball Pitching Stride Length: Normal Values and Correlation With Field Testing

PubMed Central

Fry, Karl E.; Pipkin, Andrew; Wittman, Kelcie; Hetzel, Scott; Sherry, Marc

2016-01-01

Background: Pitching biomechanical analysis has been recommended as an important component of performance, injury prevention, and rehabilitation. Normal values for youth pitching stride length have not been established, leading to application of normative values found among professional pitchers to youth pitchers. Hypotheses: The average youth pitching stride length will be significantly less than that of college and professional pitchers. There will be a positive correlation between stride length, lower extremity power, balance, and pitching experience. Study Design: Prospective cohort study. Level of Evidence: Level 3. Methods: Ninety-two youth baseball pitchers (aged 9-14 years) met the inclusion/exclusion criteria and completed the study. Stride length was recorded using a Dartfish video system over 3 maximal effort pitches. Both intra- and interrater reliability was calculated for the assessment of stride length. Double-leg vertical jump, single-leg stance time, leg length, weight, age, and pitching experience were also recorded. Results: Mean (SD) stride length was 66.0% (7.1%) of height. Stride length was correlated (P < 0.01) with vertical jump (0.38), pitching experience (0.36), and single-leg balance (0.28), with excellent intra- and interrater reliability (0.985 or higher). No significant correlations between stride length and body weight, leg length, or age existed. Conclusions: There was a significant difference between youth pitching stride length and the current published norms for older and more elite throwers. There was a positive correlation between stride length and lower extremity power, pitching experience, and single-leg balance. Clinical Relevance: Two-dimensional analysis of stride length allows for the assessment of pitching biomechanics in a practical manner. These values can be used for return to pitching parameters after an injury and designing injury prevention and performance programs. PMID:27864504

Youth Baseball Pitching Stride Length: Normal Values and Correlation With Field Testing.

PubMed

Fry, Karl E; Pipkin, Andrew; Wittman, Kelcie; Hetzel, Scott; Sherry, Marc

Pitching biomechanical analysis has been recommended as an important component of performance, injury prevention, and rehabilitation. Normal values for youth pitching stride length have not been established, leading to application of normative values found among professional pitchers to youth pitchers. The average youth pitching stride length will be significantly less than that of college and professional pitchers. There will be a positive correlation between stride length, lower extremity power, balance, and pitching experience. Prospective cohort study. Level 3. Ninety-two youth baseball pitchers (aged 9-14 years) met the inclusion/exclusion criteria and completed the study. Stride length was recorded using a Dartfish video system over 3 maximal effort pitches. Both intra- and interrater reliability was calculated for the assessment of stride length. Double-leg vertical jump, single-leg stance time, leg length, weight, age, and pitching experience were also recorded. Mean (SD) stride length was 66.0% (7.1%) of height. Stride length was correlated ( P < 0.01) with vertical jump (0.38), pitching experience (0.36), and single-leg balance (0.28), with excellent intra- and interrater reliability (0.985 or higher). No significant correlations between stride length and body weight, leg length, or age existed. There was a significant difference between youth pitching stride length and the current published norms for older and more elite throwers. There was a positive correlation between stride length and lower extremity power, pitching experience, and single-leg balance. Two-dimensional analysis of stride length allows for the assessment of pitching biomechanics in a practical manner. These values can be used for return to pitching parameters after an injury and designing injury prevention and performance programs.

Are differences in leg length predictive of lateral patello-femoral pain?

PubMed

Carlson, Mary; Wilkerson, Jerry

2007-03-01

Lateral patello-femoral pain can shorten an athletic career and generally decrease an individual's physical activity and functional level, such as preventing stair climbing and reducing the ability to rise from a chair. Leg length inequality is associated with patello-femoral pain. A leg length test that best distinguishes the difference between people who have lateral patello-femoral pain and those who do not would have clinical utility. The purpose of the present study was, first, to determine if unilateral, lateral patello-femoral pain was associated with the longer leg when inequality of leg lengths existed and, second, to determine if leg length direct measurement, indirect measurement or quadriceps angle (Q angle) could correctly classify participants according to the presence or absence of patello-femoral pain. The study used an ex post facto, two-group quasi-experimental design. A volunteer sample of 52 participants (14 males, 38 females), ranged in age from 18 to 52 years. Three methods were used to measure leg lengths: palpation meter (PALM) on anterior superior iliac spines (ASIS) while participants maintained centred weight-bearing position on a high resolution pressure mat; tape measurement from ASIS to medial malleolus (supine); tape measurement from ASIS to lateral malleolus (supine). Additionally, Q angle was measured in supine position. Patellar grind test, medial retinacular and lateral patellar palpation screened for patello-femoral pain. Logistic regression analysis determined correctness of membership in painful and non-painful patello-femoral groups. The PALM method of indirect measurement of leg length differences overall correctly classified approximately 83 % of the participants. Tape measure to medial and lateral malleoli as well as Q angle did not yield significant results. The results suggested that the PALM method of measuring leg length differences may have clinical utility in differentiating between patients who are likely to sustain patello-femoral pain syndrome and those who will not.

The effect of leg preference on postural stability in healthy athletes.

PubMed

Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; Hupperets, Maarten D W; van Dieën, Jaap H

2014-01-03

In research regarding postural stability, leg preference is often tested and controlled for. However, leg preference may vary between tasks. As athletes are a group of interest for postural stability testing, we evaluated the effect of five leg preference tasks categorization (step up, hop, ball kick, balance, pick up) on single-leg postural stability of 16 field hockey athletes. The 'center of pressure speed' was calculated as the primary outcome variable of single-leg postural stability. Secondary variables were 'mean length of the GRF vector in the horizontal plane', 'mean length of the ankle angular velocity vector', and 'mean length of the hip angular velocity vector', as well as the separate outcomes per degree of freedom. Results showed that leg preference was inconsistent between leg preference tasks. Moreover, the primary and secondary variables yielded no significant difference between the preferred and non-preferred legs, regardless of the applied leg preference task categorization (p>0.05). The present findings do not support the usability of leg preference tasks in controlling for bias of postural stability. In conclusion, none of the applied leg preference tasks revealed a significant effect on postural stability in healthy field hockey athletes. © 2013 Published by Elsevier Ltd.

Leg length, skull circumference, and the prevalence of dementia in low and middle income countries; a 10/66 population-based cross sectional survey

PubMed Central

Prince, Martin; Acosta, Daisy; Dangour, Alan D; Uauy, Ricardo; Guerra, Mariella; Huang, Yueqin; Jacob, KS; Llibre Rodriguez, Juan J.; Salas, Aquiles; Sosa, Ana Luisa; Williams, Joseph D.; Acosta, Isaac; Albanese, Emiliano; Dewey, Michael E.; Ferri, Cleusa P.; Stewart, Robert; Gaona, Ciro; Jotheeswaran, AT.; Senthil Kumar, P; Li, Shuran; Llibre Guerra, Juan C.; Rodriguez, Diana; Rodriguez, Guillermina

2017-01-01

Background Adult leg length is influenced by nutrition in the first few years of life. Adult head circumference is an indicator of brain growth. There is a limited literature linking short legs and small skulls to an increased risk for cognitive impairment and dementia in late life. Methods One phase cross-sectional surveys of all over 65 year old residents (n=14,960) in 11 catchment areas in China, India, Cuba, Dominican Republic, Venezuela, Mexico and Peru. The cross-culturally validated 10/66 dementia diagnosis, and a sociodemographic and risk factor questionnaire were administered to all participants, and anthropometric measures taken. Poisson regression was used to calculate prevalence ratios for the effect of leg length and skull circumference upon 10/66 Dementia, controlling for age, gender, education and family history of dementia. Results The pooled meta-analysed fixed effect for leg length (highest vs. lowest quarter) was 0.82 (95% CI, 0.68-0.98) and for skull circumference 0.75 (95% CI, 0.63-0.89). While point estimates varied between sites, the proportion of the variability attributable to heterogeneity between studies as opposed to sampling error (I2) was 0% for leg length and 22% for skull circumference. The effects were independent and not mediated by family history of dementia. The effect of skull circumference was not modified by educational level or gender, and the effect of leg length was not modified by gender. Conclusions Since leg length and skull circumference are said to remain stable throughout adulthood into old age, reverse causality is an unlikely explanation for the findings. Early life nutritional programming, as well as neurodevelopment may protect against neurodegeneration. PMID:20701817

A comparison and update of direct kinematic-kinetic models of leg stiffness in human running.

PubMed

Liew, Bernard X W; Morris, Susan; Masters, Ashleigh; Netto, Kevin

2017-11-07

Direct kinematic-kinetic modelling currently represents the "Gold-standard" in leg stiffness quantification during three-dimensional (3D) motion capture experiments. However, the medial-lateral components of ground reaction force and leg length have been neglected in current leg stiffness formulations. It is unknown if accounting for all 3D would alter healthy biologic estimates of leg stiffness, compared to present direct modelling methods. This study compared running leg stiffness derived from a new method (multiplanar method) which includes all three Cartesian axes, against current methods which either only include the vertical axis (line method) or only the plane of progression (uniplanar method). Twenty healthy female runners performed shod overground running at 5.0 m/s. Three-dimensional motion capture and synchronised in-ground force plates were used to track the change in length of the leg vector (hip joint centre to centre of pressure) and resultant projected ground reaction force. Leg stiffness was expressed as dimensionless units, as a percentage of an individual's bodyweight divided by standing leg length (BW/LL). Leg stiffness using the line method was larger than the uniplanar method by 15.6%BW/LL (P < .001), and multiplanar method by 24.2%BW/LL (P < .001). Leg stiffness from the uniplanar method was larger than the multiplanar method by 8.5%BW/LL (6.5 kN/m) (P < .001). The inclusion of medial-lateral components significantly increased leg deformation magnitude, accounting for the reduction in leg stiffness estimate with the multiplanar method. Given that limb movements typically occur in 3D, the new multiplanar method provides the most complete accounting of all force and length components in leg stiffness calculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Arthrodesis without bone fusion with an intramedullary modular nail for revision of infected total knee arthroplasty].

PubMed

Miralles-Muñoz, F A; Lizaur-Utrilla, A; Manrique-Lipa, C; López-Prats, F A

2014-01-01

To evaluate the outcome of knee fixation without bone fusion using an intramedullary modular nail and interposed cement. Retrospective study of 29 infected total knee arthroplasties with prospective data collection and a mean follow-up of 4.2 years (3-5). Complications included 2 recurrent infections, 1 peri-implant fracture, and 1 cortical erosion due to the tip of the femoral component. All of these were revised with successful results. The mean limb length discrepancy was 0.8 cm, with 24<1cm. Twenty-five patients reported no pain. The mean WOMAC-pain was 86.9, WOMAC-function 56.4, SF12-physical 45.1, and SF12-mental 53.7. Four patients needed a walking frame, and only two were dependent for daily activities. The Endo-Model Link nail is an effective method for knee fixation that restores the anatomical alignment of the limb with adequate leg length. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

Tibial lengthening using a reamed type intramedullary nail and an Ilizarov external fixator

PubMed Central

Kim, Hayoung; Kim, Kap Jung; Ahn, Jae Hoon; Choy, Won Sik; Kim, Yong In; Koo, Jea Yun

2008-01-01

The aim of this study was to evaluate the efficacy of tibial lengthening using a reamed type intramedullary nail and an Ilizarov external fixator for the treatment of leg length discrepancy or short stature. This retrospective study was performed on 18 tibiae (13 patients) in which attempts were made to reduce complications. We used an Ilizarov external fixator and a nail (10 mm diameter in 17 tibiae and 11 mm in one tibia) in combination. Average limb lengthening was 4.19 cm (range, 2.5–5.5). The mean duration of external fixation was 12.58 days per centimetre gain in length, and the mean consolidation index was 40.53 (range, 35.45–51.85). All distracted segments healed spontaneously without refracture or malalignment. Gradual limb lengthening using a reamed type intramedullary nail and circular external fixation in combination was found to be reliable and effective and reduced external fixation time with fewer complications. PMID:18415098

Reconstruction of juxta-articular huge defects of distal femur with vascularized fibular bone graft and Ilizarov's distraction osteogenesis.

PubMed

Lai, Davy; Chen, Chuan-Mu; Chiu, Fang-Yao; Chang, Ming-Chau; Chen, Tain-Hsiung

2007-01-01

We evaluate the effect of reconstructing huge defects (mean, 15.8 cm) of the distal femur with Ilizarov's distraction osteogenesis and free twin-barreled vascularized fibular bone graft (TVFG). We retrospectively reviewed a consecutive series of five patients who had cases of distal femoral fractures with huge defects and infection that were treated by the Ilizarov's distraction osteogenesis. After radical debridement, two of the five cases had free TVFG and monolocal distraction osteogenesis, and another two cases had multilocal distraction osteogenesis with knee fusion because of loss of the joint congruity. The other case with floating knee injury had bilocal distraction osteogenesis and a preserved knee joint. The mean defect of distal femur was 15.8 cm (range, 14-18 cm) in length. The mean length of distraction osteogenesis by Ilizarov's apparatus was 8.2 cm. The mean length of TVFG was 8 cm. The average duration from application of Ilizarov's apparatus to achievement of bony union was 10.2 months (range, 8-13 months). At the end of the follow-up, ranges of motion of three knees were 0 to 45 degrees, 0 to 60 degrees, and 0 to 90 degrees. Two cases had knee arthrodesis with bony fusion because of loss of the joint congruity. There were no leg length discrepancies in all five patients. In addition, three patients had pin tract infections and one case had a 10 degree varus deformity of the femur. Juxta-articular huge defect (>10 cm) of distal femur remains a challenge to orthopedic surgeons. Ilizarov's technique provides the capability to maintain stability, eradicate infection, restore leg length, and to perform adjuvant reconstructive procedure easily. In this study, we found that combining Ilizarov's distraction osteogenesis with TVFG results in improved patient outcome for patients with injuries such as supracondylar or intercondylar infected fractures or nonunion of distal femur with huge bone defect.

Stride length: the impact on propulsion and bracing ground reaction force in overhand throwing.

PubMed

Ramsey, Dan K; Crotin, Ryan L

2018-03-26

Propulsion and bracing ground reaction force (GRF) in overhand throwing are integral in propagating joint reaction kinetics and ball velocity, yet how stride length effects drive (hind) and stride (lead) leg GRF profiles remain unknown. Using a randomised crossover design, 19 pitchers (15 collegiate and 4 high school) were assigned to throw 2 simulated 80-pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and radar gun tracked each throw. Vertical and anterior-posterior GRF was normalised then impulse was derived. Paired t-tests identified whether differences between conditions were significant. Late in single leg support, peak propulsion GRF was statistically greater for the drive leg with increased stride. Stride leg peak vertical GRF in braking occurred before acceleration with longer strides, but near ball release with shorter strides. Greater posterior shear GRF involving both legs demonstrated increased braking with longer strides. Conversely, decreased drive leg propulsion reduced both legs' braking effects with shorter strides. Results suggest an interconnection between normalised stride length and GRF application in propulsion and bracing. This work has shown stride length to be an important kinematic factor affecting the magnitude and timing of external forces acting upon the body.

The desert ant odometer: a stride integrator that accounts for stride length and walking speed.

PubMed

Wittlinger, Matthias; Wehner, Rüdiger; Wolf, Harald

2007-01-01

Desert ants, Cataglyphis, use path integration as a major means of navigation. Path integration requires measurement of two parameters, namely, direction and distance of travel. Directional information is provided by a celestial compass, whereas distance measurement is accomplished by a stride integrator, or pedometer. Here we examine the recently demonstrated pedometer function in more detail. By manipulating leg lengths in foraging desert ants we could also change their stride lengths. Ants with elongated legs ('stilts') or shortened legs ('stumps') take larger or shorter strides, respectively, and misgauge travel distance. Travel distance is overestimated by experimental animals walking on stilts, and underestimated by animals walking on stumps - strongly indicative of stride integrator function in distance measurement. High-speed video analysis was used to examine the actual changes in stride length, stride frequency and walking speed caused by the manipulations of leg length. Unexpectedly, quantitative characteristics of walking behaviour remained almost unaffected by imposed changes in leg length, demonstrating remarkable robustness of leg coordination and walking performance. These data further allowed normalisation of homing distances displayed by manipulated animals with regard to scaling and speed effects. The predicted changes in homing distance are in quantitative agreement with the experimental data, further supporting the pedometer hypothesis.

Head circumference, leg length and its association with dementia among older adult population in Singapore.

PubMed

Chang, Sherilyn; Ong, Hui Lin; Abdin, Edimansyah; Vaingankar, Janhavi Ajit; Jeyagurunathan, Anitha; Shafie, Saleha; Mahendran, Rathi; Subramaniam, Mythily; Chong, Siow Ann

2017-12-01

Head circumference and leg length serve as reliable proxy indicators of early-life environment. Research studies have shown that these anthropometric measurements are associated with cognitive impairment and dementia among older adults. The aim of the present study was to assess the associations between dementia with head circumference and leg length among the older adult population in Singapore. This study also aimed to examine the sociodemographic correlates of these anthropometric measurements. Data were collected from 2565 older adults aged 60 years and above, in a population study on the Well-being of the Singapore Elderly. Head circumference and leg length measurements were obtained, and sociodemographic information was recorded. Dementia diagnosis was made using the 10/66 dementia algorithm. Anthropometric measurements were first stratified into quarters, and then logistic regression analysis was used to examine factors associated with head circumference and leg length, as well as to examine the association between dementia with these measurements. Sociodemographic correlates of head circumference and leg length include age, gender, ethnicity and education level. Smaller head circumference was independently associated with higher odds of 10/66 dementia (OR = 2.173-2.709). When the regression analysis was stratified by gender, the association was found only in the male sample. Leg length was not significantly associated with dementia after controlling for sociodemographic variables. Smaller head circumference is independently associated with dementia among older adults in Singapore. Findings from this study suggest that risk factors for dementia begin their influence in early life. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

All-inside, physeal-sparing anterior cruciate ligament reconstruction does not significantly compromise the physis in skeletally immature athletes: a postoperative physeal magnetic resonance imaging analysis.

PubMed

Nawabi, Danyal H; Jones, Kristofer J; Lurie, Brett; Potter, Hollis G; Green, Daniel W; Cordasco, Frank A

2014-12-01

Anterior cruciate ligament (ACL) reconstruction in skeletally immature patients can result in growth disturbance due to iatrogenic physeal injury. Multiple physeal-sparing ACL reconstruction techniques have been described; however, few combine the benefits of anatomic reconstruction using sockets without violation of the femoral or tibial physis. To utilize physeal-specific magnetic resonance imaging (MRI) to quantify the zone of physeal injury after all-inside ACL reconstruction in skeletally immature athletes. Case series; Level of evidence, 4. Twenty-three skeletally immature patients (mean chronologic age 12.6 years; range, 10-15 years) were prospectively evaluated after all-inside ACL reconstruction. The mean bone age was 13.2 years. There were 8 females and 15 males. Fifteen patients underwent an all-epiphyseal (AE) ACL reconstruction and 8 patients had a partial transphyseal (PTP) ACL reconstruction, which spared the femoral physis but crossed the tibial physis. At 6 and 12 months postoperatively, MRI using 3-dimensional fat-suppressed spoiled gradient recalled echo sequences and full-length standing radiographs were performed to assess graft survival, growth arrest, physeal violation, angular deformity, and leg length discrepancy. The mean follow-up for this cohort was 18.5 months (range, 12-39 months). Minimal tibial physeal violation was seen in 10 of 15 patients in the AE group and, by definition, all patients in the PTP group. The mean area of tibial physeal disturbance (±SD) was 57.8 ± 52.2 mm(2) (mean 2.1% of total physeal area) in the AE group compared with 145.1 ± 100.6 mm(2) (mean 5.4% of total physeal area) in the PTP group (P = .003). Minimal compromise of the femoral physis (1.5%) was observed in 1 case in the PTP group and no cases in the AE group. No cases of growth arrest, articular surface violation, or avascular necrosis were noted on MRI. No postoperative angular deformities or significant leg length discrepancies were observed. The study data suggest that all-inside ACL reconstruction is a safe technique for skeletally immature athletes at short-term follow-up. Physeal-specific MRI reveals minimal growth plate compromise that is significantly lower than published thresholds for growth arrest. © 2014 The Author(s).

Leg length, sitting height, and body proportions references for achondroplasia: New tools for monitoring growth.

PubMed

Del Pino, Mariana; Ramos Mejía, Rosario; Fano, Virginia

2018-04-01

Achondroplasia is the most common form of inherited disproportionate short stature. We report leg length, sitting height, and body proportion curves for achondroplasia. Seven centile format of sitting height, leg length, sitting height/leg length ratio, sitting height/height ratio, and head circumference/height ratio were estimated by the LMS method. The Q-test was applied to assess the goodness of fit. For comparison, centiles of sitting height and leg length were graphed using Argentine national growth references for achondroplasia and non-achondroplasia populations. The sample consisted of 342 children with achondroplasia (171 males, 171 females) aged 0-18 years. The median (interquartile range) number of measurements per child was 6 (3, 12) for sitting height and 8 (3, 13) for head circumference. Median leg length increased from 14 cm at age 1 week to 44 and 40 cm (males and females, respectively) in achondroplasia adolescents which is 3.5 cm shorter than non-achondroplasia children at age 1 week and, 38 cm shorter at adolescence. Median sitting height increased from 34 cm at birth to 86 and 81 in adolescents' boys and girls respectively, only 5 cm shorter than non-achondroplasia children. Sitting height/leg length decreased from 2.61 at birth to approximately 1.90 at adolescent. Median head circumference/height ratio decreased from 0.79 at birth to 0.46 at 18 years in both sexes. Growth of lower limbs is affected early in life and becomes more noticeable throughout childhood. The disharmonic growth between the less affected trunk and the severely affected limbs determine body disproportion in achondroplasia. © 2018 Wiley Periodicals, Inc.

Height, age at menarche and risk of hormone receptor-positive and -negative breast cancer: a cohort study.

PubMed

Ritte, Rebecca; Lukanova, Annekatrin; Tjønneland, Anne; Olsen, Anja; Overvad, Kim; Mesrine, Sylvie; Fagherazzi, Guy; Dossus, Laure; Teucher, Birgit; Steindorf, Karen; Boeing, Heiner; Aleksandrova, Krasimira; Trichopoulou, Antonia; Lagiou, Pagona; Trichopoulos, Dimitrios; Palli, Domenico; Grioni, Sara; Mattiello, Amalia; Tumino, Rosario; Sacerdote, Carlotta; Quirós, José Ramón; Buckland, Genevieve; Molina-Montes, Esther; Chirlaque, María-Dolores; Ardanaz, Eva; Amiano, Pilar; Bueno-de-Mesquita, Bas; van Duijnhoven, Franzel; van Gils, Carla H; Peeters, Petra Hm; Wareham, Nick; Khaw, Kay-Tee; Key, Timothy J; Travis, Ruth C; Krum-Hansen, Sanda; Gram, Inger Torhild; Lund, Eiliv; Sund, Malin; Andersson, Anne; Romieu, Isabelle; Rinaldi, Sabina; McCormack, Valerie; Riboli, Elio; Kaaks, Rudolf

2013-06-01

Associations of breast cancer overall with indicators of exposures during puberty are reasonably well characterized; however, uncertainty remains regarding the associations of height, leg length, sitting height and menarcheal age with hormone receptor-defined malignancies. Within the European Prospective Investigation into Cancer and Nutrition cohort, Cox proportional hazards models were used to describe the relationships of adult height, leg length and sitting height and age at menarche with risk of estrogen and progesterone receptor negative (ER-PR-) (n = 990) and ER+PR+ (n = 3,524) breast tumors. Height as a single risk factor was compared to a model combining leg length and sitting height. The possible interactions of height, leg length and sitting height with menarche were also analyzed. Risk of both ER-PR- and ER+PR+ malignancies was positively associated with standing height, leg length and sitting height and inversely associated with increasing age at menarche. For ER+PR+ disease, sitting height (hazard ratios: 1.14[95% confidence interval: 1.08-1.20]) had a stronger risk association than leg length (1.05[1.00-1.11]). In comparison, for ER-PR- disease, no distinct differences were observed between leg length and sitting height. Women who were tall and had an early menarche (≤13 years) showed an almost twofold increase in risk of ER+PR+ tumors but no such increase in risk was observed for ER-PR- disease. Indicators of exposures during rapid growth periods were associated with risks of both HR-defined breast cancers. Exposures during childhood promoting faster development may establish risk associations for both HR-positive and -negative malignancies. The stronger associations of the components of height with ER+PR+ tumors among older women suggest possible hormonal links that could be specific for postmenopausal women. Copyright © 2012 UICC.

The role of skin biopsy in differentiating small-fiber neuropathy from ganglionopathy.

PubMed

Provitera, V; Gibbons, C H; Wendelschafer-Crabb, G; Donadio, V; Vitale, D F; Loavenbruck, A; Stancanelli, A; Caporaso, G; Liguori, R; Wang, N; Santoro, L; Kennedy, W R; Nolano, M

2018-06-01

We aimed to test the clinical utility of the leg:thigh intraepidermal nerve-fiber (IENF) density ratio as a parameter to discriminate between length-dependent small-fiber neuropathy (SFN) and small-fiber sensory ganglionopathy (SFSG) in subjects with signs and symptoms of small-fiber pathology. We retrospectively evaluated thigh and leg IENF density in 314 subjects with small-fiber pathology (173 with distal symmetrical length-dependent SFN and 141 with non-length-dependent SFSG). A group of 288 healthy subjects was included as a control group. The leg:thigh IENF density ratio was calculated for all subjects. We used receiver operating characteristic curve analyses to assess the ability of this parameter to discriminate between length-dependent SFN and SFSG, and the decision curve analysis to estimate its net clinical benefit. In patients with neuropathy, the mean IENF density was 14.8 ± 6.8/mm at the thigh (14.0 ± 6.9/mm in length-dependent SFN and 15.9 ± 6.7/mm in patients with SFSG) and 7.5 ± 4.5/mm at the distal leg (5.4 ± 3.2/mm in patients with length-dependent SFN and 10.1 ± 4.6/mm in patients with SFSG). The leg:thigh IENF density ratio was significantly (P < 0.01) lower in patients with length-dependent SFN (0.44 ± 0.23) compared with patients with SFSG (0.68 ± 0.28). The area under the curve of the receiver operating characteristic analysis to discriminate between patients with length-dependent SFN and SFSG was 0.79. The decision curve analysis demonstrated the clinical utility of this parameter. The leg:thigh IENF ratio represents a valuable tool in the differential diagnosis between SFSG and length-dependent SFN. © 2018 EAN.

Limb lengthening and peripheral nerve function—factors associated with deterioration of conduction

PubMed Central

2013-01-01

Background and purpose Limb lengthening is performed for a diverse range of orthopedic problems. A high rate of complications has been reported in these patients, which include motor and sensory loss as a result of nerve damage. We investigated the effect of limb lengthening on peripheral nerve function. Patients and methods 36 patients underwent electrophysiological testing at 3 points: (1) preoperatively, (2) after application of external fixator/corticotomy but before lengthening, and (3) after lengthening. The limb-length discrepancy was due to a congenital etiology (n = 19), a growth disturbance (n = 9), or a traumatic etiology (n = 8). Results 2 of the traumatic etiology patients had significant changes evident on electrophysiological testing preoperatively. They both deteriorated further with lengthening. 7 of the 21 patients studied showed deterioration in nerve function after lengthening, but not postoperatively, indicating that this was due to the lengthening process and not to the surgical procedure. All of these patients had a congenital etiology for their leg-length discrepancy. Interpretation As detailed electrophysiological tests were carried out before surgery, after surgery but before lengthening, and finally after completion of lengthening, it was possible to distinguish between the effects of the operation and the effects of lengthening on nerve function. The results indicate that the etiology, site (femur or tibia), and nerve (common peroneal or tibial) had a bearing on the risk of nerve injury and that these factors had a far greater effect than the total amount of lengthening. PMID:24171677

16 CFR 1512.19 - Instructions and labeling.

Code of Federal Regulations, 2012 CFR

2012-01-01

... assembly and adjustment, (2) a drawing illustrating the minimum leg-length dimension of a rider and a method of measurement of this dimension. (c) The minimum leg-length dimension shall be readily...

Leg lengthening and shortening

MedlinePlus

... to match its length. Proper timing of this treatment is important for best results. Certain health conditions can lead to very unequal leg lengths. They include: Poliomyelitis Cerebral palsy Small, weak muscles or short, tight ( ...

Pelvic step: the contribution of horizontal pelvis rotation to step length in young healthy adults walking on a treadmill.

PubMed

Liang, Bo Wei; Wu, Wen Hua; Meijer, Onno G; Lin, Jian Hua; Lv, Go Rong; Lin, Xiao Cong; Prins, Maarten R; Hu, Hai; van Dieën, Jaap H; Bruijn, Sjoerd M

2014-01-01

Transverse plane pelvis rotations during walking may be regarded as the "first determinant of gait". This would assume that pelvis rotations increase step length, and thereby reduce the vertical movements of the centre of mass-"the pelvic step". We analysed the pelvic step using 20 healthy young male subjects, walking on a treadmill at 1-5 km/h, with normal or big steps. Step length, pelvis rotation amplitude, leg-pelvis relative phase, and the contribution of pelvis rotation to step length were calculated. When speed increased in normal walking, pelvis rotation changed from more out-of-phase to in-phase with the upper leg. Consequently, the contribution of pelvis rotation to step length was negative at lower speeds, switching to positive at 3 km/h. With big steps, leg and pelvis were more in-phase, and the contribution of pelvis rotation to step length was always positive, and relatively large. Still, the overall contribution of pelvis rotations to step length was small, less than 3%. Regression analysis revealed that leg-pelvis relative phase predicted about 60% of the variance of this contribution. The results of the present study suggest that, during normal slow walking, pelvis rotations increase, rather than decrease, the vertical movements of the centre of mass. With large steps, this does not happen, because leg and pelvis are in-phase at all speeds. Finally, it has been suggested that patients with hip flexion limitation may use larger pelvis rotations to increase step length. This, however, may only work as long as the pelvis rotates in-phase with the leg. Copyright © 2013 Elsevier B.V. All rights reserved.

On reconstructing Giraffa sivalensis, an extinct giraffid from the Siwalik Hills, India

PubMed Central

Mitchell, Graham

2015-01-01

Giraffa sivalensis occurred during the Plio-Pleistocene period and probably represents the terminal species of the genus in Southern Asia. The holotype is an almost perfectly preserved cervical vertebra of disputed anatomical location. Although there is also uncertainty regarding this animal’s size, other specimens that have been assigned to this species include fragments of two humeri, a radius, metacarpi and teeth. Here we estimate neck length, leg length and body mass using interspecific and, unusually, ontogenetic allometry of extant giraffe skeletal parameters. The appropriateness of each equation to estimate body mass was evaluated by calculating the prediction error incurred in both extant giraffes (G. camelopardalis) and okapis (Okapia johnstoni). It followed that the equations with the lowest prediction error in both species were considered robust enough to use in G. sivalensis. The size of G. sivalensis, based on the holotype, is proposed as 400 kg (range 228 kg–575 kg), with a neck length of approximately 147 cm and a height of 390 cm. The molar lengths of tooth specimens considered agree with this size estimate. The humerus was the most appropriate long bone to establish body mass, which estimates a heavier animal of ca 790 kg. The discrepancy with the vertebral body weight estimate might indicate sexual dimorphism. Radial and metacarpal specimens estimate G. sivalensis to be as heavy as extant giraffes. This may indicate that the radius and metacarpus are unsuitable for body mass predictions in Giraffa spp. Alternatively, certain long bones may have belonged to another long legged giraffid that occurred during the same period and locality as G. sivalensis. We have concluded that if sexual dimorphism was present then males would have been about twice the size of females. If sexual dimorphism was not present and all bones were correctly attributed to this species, then G. sivalensis had a slender neck with a relatively stocky body. PMID:26290791

Leg length, skull circumference, and the incidence of dementia in Latin America and China: A 10/66 population-based cohort study.

PubMed

Prince, Martin J; Acosta, Daisy; Guerra, Mariella; Huang, Yueqin; Jimenez-Velazquez, Ivonne Z; Llibre Rodriguez, Juan J; Salas, Aquiles; Sosa, Ana Luisa; Dewey, Michael E; Guerchet, Maelenn M; Liu, Zhaorui; Llibre Guerra, Jorge J; Prina, A Matthew

2018-01-01

Adult leg length is influenced by nutrition in the first few years of life. Adult head circumference is an indicator of brain growth. Cross-sectional studies indicate inverse associations with dementia risk, but there have been few prospective studies. Population-based cohort studies in urban sites in Cuba, Dominican Republic Puerto Rico and Venezuela, and rural and urban sites in Peru, Mexico and China. Sociodemographic and risk factor questionnaires were administered to all participants, and anthropometric measures taken, with ascertainment of incident dementia, and mortality, three to five years later. Of the original at risk cohort of 13,587 persons aged 65 years and over, 2,443 (18.0%) were lost to follow-up; 10,540 persons with skull circumference assessments were followed up for 40,466 person years, and 10,400 with leg length assessments were followed up for 39,954 person years. There were 1,009 cases of incident dementia, and 1,605 dementia free deaths. The fixed effect pooled meta-analysed adjusted subhazard ratio (ASHR) for leg length (highest vs. lowest quarter) was 0.80 (95% CI, 0.66-0.97) and for skull circumference was 1.02 (95% CI, 0.84-1.25), with no heterogeneity of effect between sites (I2 = 0%). Leg length measurements tended to be shorter at follow-up, particularly for those with baseline cognitive impairment and dementia. However, leg length change was not associated with dementia incidence (ASHR, per cm 1.006, 95% CI 0.992-1.020), and the effect of leg length was little altered after adjusting for baseline frailty (ASHR 0.82, 95% CI 0.67-0.99). A priori hypotheses regarding effect modification by gender or educational level were not supported. However, the effect of skull circumference was modified by gender (M vs F ASHR 0.86, 95% CI 0.75-0.98), but in the opposite direction to that hypothesized with a greater protective effect of larger skull dimensions in men. Consistent findings across settings provide quite strong support for an association between adult leg length and dementia incidence in late-life. Leg length is a relatively stable marker of early life nutritional programming, which may confer brain reserve and protect against neurodegeneration in later life through mitigation of cardiometabolic risk. Further clarification of these associations could inform predictive models for future dementia incidence in the context of secular trends in adult height, and invigorate global efforts to improve childhood nutrition, growth and development.

Human and avian running on uneven ground: a model-based comparison

PubMed Central

Birn-Jeffery, A. V.; Blum, Y.

2016-01-01

Birds and humans are successful bipedal runners, who have individually evolved bipedalism, but the extent of the similarities and differences of their bipedal locomotion is unknown. In turn, the anatomical differences of their locomotor systems complicate direct comparisons. However, a simplifying mechanical model, such as the conservative spring–mass model, can be used to describe both avian and human running and thus, provides a way to compare the locomotor strategies that birds and humans use when running on level and uneven ground. Although humans run with significantly steeper leg angles at touchdown and stiffer legs when compared with cursorial ground birds, swing-leg adaptations (leg angle and leg length kinematics) used by birds and humans while running appear similar across all types of uneven ground. Nevertheless, owing to morphological restrictions, the crouched avian leg has a greater range of leg angle and leg length adaptations when coping with drops and downward steps than the straight human leg. On the other hand, the straight human leg seems to use leg stiffness adaptation when coping with obstacles and upward steps unlike the crouched avian leg posture. PMID:27655670

Stature Estimation from Lower Limb Anthropometry using Linear Regression Analysis: A Study on the Malaysian Population.

PubMed

Abu Bakar, S N; Aspalilah, A; AbdelNasser, I; Nurliza, A; Hairuliza, M J; Swarhib, M; Das, S; Mohd Nor, F

2017-01-01

Stature is one of the characteristics that could be used to identify human, besides age, sex and racial affiliation. This is useful when the body found is either dismembered, mutilated or even decomposed, and helps in narrowing down the missing person's identity. The main aim of the present study was to construct regression functions for stature estimation by using lower limb bones in the Malaysian population. The sample comprised 87 adult individuals (81 males, 6 females) aged between 20 to 79 years. The parameters such as thigh length, lower leg length, leg length, foot length, foot height and foot breadth were measured. They were measured by a ruler and measuring tape. Statistical analysis involved independent t-test to analyse the difference between lower limbs in male and female. The Pearson's correlation test was used to analyse correlations between lower limb parameters and stature, and the linear regressions were used to form equations. The paired t-test was used to compare between actual stature and estimated stature by using the equations formed. Using independent t-test, there was a significant difference (p< 0.05) in the measurement between males and females with regard to leg length, thigh length, lower leg length, foot length and foot breadth. The thigh length, leg length and foot length were observed to have strong correlations with stature with p= 0.75, p= 0.81 and p= 0.69, respectively. Linear regressions were formulated for stature estimation. Paired t-test showed no significant difference between actual stature and estimated stature. It is concluded that regression functions can be used to estimate stature to identify skeletal remains in the Malaysia population.

Distance Reached in the Anteromedial Reach Test as a Function of Learning and Leg Length

ERIC Educational Resources Information Center

Bent, Nicholas P.; Rushton, Alison B.; Wright, Chris C.; Batt, Mark E.

2012-01-01

The Anteromedial Reach Test (ART) is a new outcome measure for assessing dynamic knee stability in anterior cruciate ligament-injured patients. The effect of learning and leg length on distance reached in the ART was examined. Thirty-two healthy volunteers performed 15 trials of the ART on each leg. There was a moderate correlation (r = 0.44-0.50)…

Effect of leg length inequality on body weight distribution during walking with load: A pilot study

NASA Astrophysics Data System (ADS)

Zabri, S. W. K. Ali; Basaruddin, K. S.; Salleh, A. F.; Rusli, W. M. R.; Daud, R.

2017-09-01

This paper presents a pilot study on the effect of leg length inequality (LLI) on the body weight distribution. Plywood block was used to mimic the artificial LLI. The height of the plywood was increased up to 4.0 cm with 0.5 cm increment. Hence, eight different height of LLI was considered in order to investigate which height of LLI initiated the significant effect. The experiment was conducted on a healthy subject that walking on the force plate in two conditions; with a load of 2 kg (carried by a backpack worn by the subject) and without load. Qualisys Track Manager (QTM) system was employed for data processing. The results showed that the short leg subjected to more weight compared to the long leg during walking with inequality of leg length especially when carrying additional load.

Chronic low back pain in older adults: prevalence, reliability, and validity of physical examination findings.

PubMed

Weiner, Debra K; Sakamoto, Sara; Perera, Subashan; Breuer, Paula

2006-01-01

To develop a structured physical examination protocol that identifies common biomechanical and soft-tissue abnormalities for older adults with chronic low back pain (CLBP) that can be used as a triage tool for healthcare providers and to test the interobserver reliability and discriminant validity of this protocol. Cross-sectional survey and examination. Older adult pain clinic. One hundred eleven community-dwelling adults aged 60 and older with CLBP and 20 who were pain-free. Clinical history for demographics, pain duration, previous lumbar surgery or advanced imaging, neurogenic claudication, and imaging clinically serious symptoms. Physical examination for scoliosis, functional leg length discrepancy, pain with lumbar movement, myofascial pain (paralumbar, piriformis, tensor fasciae latae (TFL)), regional bone pain (sacroiliac joint (SIJ), hip, vertebral body), and fibromyalgia. Scoliosis was prevalent in those with (77.5%) and without pain (60.0%), but prevalence of SIJ pain (84% vs 5%), fibromyalgia tender points (19% vs 0%), myofascial pain (96% vs 10%), and hip pain (48% vs 0%) was significantly different between groups (P < .001). Interrater reliability was excellent for SIJ pain (0.81), number of fibromyalgia tender points (0.84), and TFL pain (0.81); good for scoliosis (0.43), kyphosis (0.66), lumbar movement pain (0.75), piriformis pain (0.71), and hip disease by internal rotation (0.56); and marginal for leg length (0.00) and paravertebral pain (0.39). Biomechanical and soft tissue pathologies are common in older adults with CLBP, and many can be assessed reliably using a brief physical examination. Their recognition may save unnecessary healthcare expenditure and patient suffering.

Muscle fiber type, Achilles tendon length, potentiation, and running economy.

PubMed

Hunter, Gary R; McCarthy, John P; Carter, Stephen J; Bamman, Marcas M; Gaddy, Emily S; Fisher, Gordon; Katsoulis, Kostantina; Plaisance, Eric P; Newcomer, Bradley R

2015-05-01

The purpose of this investigation was to develop a potential model for how muscle fiber type, Achilles tendon length, stretch-shortening cycle potentiation (SSCP), and leg strength interact with running economy. Twenty trained male distance runners 24-40 years of age served as subjects. Running economy (net oxygen uptake) was measured while running on a treadmill. Leg press SSCP(force) and SSCP(velocity) were determined by measuring the difference in velocity between a static leg press throw and a countermovement leg press throw. Vertical jump SSCP was determined by measuring the difference in jump height between a static jump and a drop jump from a 20.3-cm bench. Tendon length was measured by magnetic resonance imaging, and muscle fiber type was made from a vastus lateralis muscle biopsy. Type IIx muscle fiber percent (r = 0.70, p < 0.001) and leg strength (r = 0.95, p < 0.001) were positively and independently related to late eccentric force development. Achilles tendon length (r = 0.42, p ≤ 0.05) and late eccentric force during stretch-shortening cycle (r = 0.76, p < 0.001) were independently related to SSCP(force). SSCP(force) was related to SSCP(velocity), which in turn was related to running economy (r = 0.61, p < 0.01). These results suggest that longer Achilles tendon length, type II fiber, and muscular leg strength may enhance the potential for SSCP, running economy, and physiological effort while running.

Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain.

PubMed

Birn-Jeffery, Aleksandra V; Hubicki, Christian M; Blum, Yvonne; Renjewski, Daniel; Hurst, Jonathan W; Daley, Monica A

2014-11-01

Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force-length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force-length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics. © 2014. Published by The Company of Biologists Ltd.

Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain

PubMed Central

Birn-Jeffery, Aleksandra V.; Hubicki, Christian M.; Blum, Yvonne; Renjewski, Daniel; Hurst, Jonathan W.; Daley, Monica A.

2014-01-01

Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force–length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force–length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics. PMID:25355848

The relationship between allometry and preferred transition speed in human locomotion.

PubMed

Ranisavljev, Igor; Ilic, Vladimir; Soldatovic, Ivan; Stefanovic, Djordje

2014-04-01

The purpose of this study was to explore the relationships between preferred transition speed (PTS) and anthropometric characteristics, body composition and different human body proportions in males. In a sample of 59 male students, we collected anthropometric and body composition data and determined individual PTS using increment protocol. The relationships between PTS and other variables were determined using Pearson correlation, stepwise linear and hierarchical regression. Body ratios were formed as quotient of two variables whereby at least one significantly correlated to PTS. Circular and transversal (except bitrochanteric diameter) body dimensions did not correlate with PTS. Moderate correlations were found between longitudinal leg dimensions (foot, leg and thigh length) and PTS, while the highest correlation was found for lower leg length (r=.488, p<.01). Two parameters related to body composition showed weak correlation with PTS: body fat mass (r=-.250, p<.05) and amount of lean leg mass scaled to body weight (r=.309, p<.05). Segmental body proportions correlated more significantly with PTS, where thigh/lower leg length ratio showed the highest correlation (r=.521, p<.01). Prediction model with individual variables (lower leg and foot length) have explained just 31% of PTS variability, while model with body proportions showed almost 20% better prediction (R(2)=.504). These results suggests that longitudinal leg dimensions have moderate influence on PTS and that segmental body proportions significantly more explain PTS than single anthropometric variables. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimal Body Size and Limb Length Ratios Associated with 100-m Personal-Best Swim Speeds.

PubMed

Nevill, Alan M; Oxford, Samuel W; Duncan, Michael J

2015-08-01

This study aims to identify optimal body size and limb segment length ratios associated with 100-m personal-best (PB) swim speeds in children and adolescents. Fifty national-standard youth swimmers (21 males and 29 females age 11-16 yr; mean ± SD age, 13.5 ± 1.5 yr) participated in the study. Anthropometry comprised stature; body mass; skinfolds; maturity offset; upper arm, lower arm, and hand lengths; and upper leg, lower leg, and foot lengths. Swimming performance was taken as the PB time recorded in competition for the 100-m freestyle swim. To identify the optimal body size and body composition components associated with 100-m PB swim speeds (having controlled for age and maturity offset), we adopted a multiplicative allometric log-linear regression model, which was refined using backward elimination. Lean body mass was the singularly most important whole-body characteristic. Stature and body mass did not contribute to the model, suggesting that the advantage of longer levers was limb-specific rather than a general whole-body advantage. The allometric model also identified that having greater limb segment length ratios [i.e., arm ratio = (low arm)/(upper arm); foot-to-leg ratio = (foot)/(lower leg)] was key to PB swim speeds. It is only by adopting multiplicative allometric models that the above mentioned ratios could have been derived. The advantage of having a greater lower arm is clear; however, having a shorter upper arm (achieved by adopting a closer elbow angle technique or by possessing a naturally endowed shorter upper arm), at the same time, is a new insight into swimming performance. A greater foot-to-lower-leg ratio suggests that a combination of larger feet and shorter lower leg length may also benefit PB swim speeds.

Total hip arthroplasty using a short-stem prosthesis: restoration of hip anatomy.

PubMed

Amenabar, Tomas; Marimuthu, Kanniraj; Hawdon, Gabrielle; Gildone, Alessandro; McMahon, Stephen

2015-04-01

To evaluate hip parameters such as vertical centre of rotation (VCR), horizontal centre of rotation (HCR), femoral offset, and leg length after total hip arthroplasty (THA) using the Nanos short-stem prosthesis. Medical records of 73 men and 74 women aged 25 to 92 (mean, 63) years who underwent THA using the Nanos short-stem prosthesis by a single surgeon were reviewed. Prior to the surgery, the optimal cup and stem size, head length, and level of the neck osteotomy were determined using radiographs. Intra-operatively, the leg length and femoral offset were checked, and the level of neck resection and head length were adjusted. VCR, HCR, femoral offset, and leg length of the operated and contralateral sides were compared. Functional outcomes were assessed using the Harris Hip Score (HHS). Compared with the normal contralateral hips, the operated hips had a mean increase of 0.4 mm in VCR (p=0.032), a mean decrease of 1.4 mm in HCR (p=0.027), a mean increase of 0.6 mm in femoral offset (p=0.043), and a mean increase of 0.36 mm in leg length (p=0.035). For these respective parameters, the difference between the normal contralateral side and the operated side was within 5 mm in 89%, 80%, 71%, and 96% of patients. The HHS improved from a mean of 53 to 91 at one year (p<0.001). THA using the Nanos short-stem prosthesis enabled restoration of hip anatomy (VCR, HCR, femoral offset, and leg length).

New method of limb deformities correction in children.

PubMed Central

Atar, D.; Lehman, W. B.; Grant, A. D.; Strongwater, A.; Frankel, V. H.; Posner, M.; Golyakhovsky, V.

1992-01-01

A new "bloodless" technique (Ilizarov) was used to correct 36 limb deformities in 29 children. There were six leg length discrepancies, five achondroplasias, four deformed feet, five joint contractures, one rotational deformity of tibia, and in three the apparatus was used as an external fixator after corrective osteotomy. Lengthening was accomplished in 15 of the 16 procedures (93%). Average increase in femur length was 10 cm (32%), in tibial length 7.5 cm (30%), in humerus 11 cm (40%). Bony union was achieved in two out of five pseudoarthroses. Four deformed feet were fully corrected. Joint contractures were corrected in four out of five. The complication rate is as high as in other methods but with the Ilizarov apparatus, longer segments of bone were lengthened and more complex deformities were treated. Complications lessened as experience was gained. Images Fig. 1a,b Fig. 1 Fig. 1c Fig. 1d Fig. 1e Fig. 2a Fig. 2b Fig. 2c Fig. 2d Fig. 2e Fig. 3a Fig. 3b Fig. 3c Fig. 3d Fig. 4a Fig. 4b Fig. 4c Fig. 4d Fig. 4e Fig. 5a Fig. 5b Fig. 5c Fig. 5d PMID:1490205

Digital templating for THA: a simple computer-assisted application for complex hip arthritis cases.

PubMed

Hafez, Mahmoud A; Ragheb, Gad; Hamed, Adel; Ali, Amr; Karim, Said

2016-10-01

Total hip arthroplasty (THA) is the standard procedure for end-stage arthritis of the hip. Its technical success relies on preoperative planning of the surgical procedure and virtual setup of the operative performance. Digital hip templating is one methodology of preoperative planning for THA which requires a digital preoperative radiograph and a computer with special software. This is a prospective study involving 23 patients (25 hips) who were candidates for complex THA surgery (unilateral or bilateral). Digital templating is done by radiographic assessment using radiographic magnification correction, leg length discrepancy and correction measurements, acetabular component and femoral component templating as well as neck resection measurement. The overall accuracy for templating the stem implant's exact size is 81%. This percentage increased to 94% when considering sizing within 1 size. Digital templating has proven effective, reliable and essential technique for preoperative planning and accurate prediction of THA sizing and alignment.

Mechanical and energetic consequences of rolling foot shape in human walking

PubMed Central

Adamczyk, Peter G.; Kuo, Arthur D.

2013-01-01

SUMMARY During human walking, the center of pressure under the foot progresses forward smoothly during each step, creating a wheel-like motion between the leg and the ground. This rolling motion might appear to aid walking economy, but the mechanisms that may lead to such a benefit are unclear, as the leg is not literally a wheel. We propose that there is indeed a benefit, but less from rolling than from smoother transitions between pendulum-like stance legs. The velocity of the body center of mass (COM) must be redirected in that transition, and a longer foot reduces the work required for the redirection. Here we develop a dynamic walking model that predicts different effects from altering foot length as opposed to foot radius, and test it by attaching rigid, arc-like foot bottoms to humans walking with fixed ankles. The model suggests that smooth rolling is relatively insensitive to arc radius, whereas work for the step-to-step transition decreases approximately quadratically with foot length. We measured the separate effects of arc-foot length and radius on COM velocity fluctuations, work performed by the legs and metabolic cost. Experimental data (N=8) show that foot length indeed has much greater effect on both the mechanical work of the step-to-step transition (23% variation, P=0.04) and the overall energetic cost of walking (6%, P=0.03) than foot radius (no significant effect, P>0.05). We found the minimum metabolic energy cost for an arc foot length of approximately 29% of leg length, roughly comparable to human foot length. Our results suggest that the foot's apparently wheel-like action derives less benefit from rolling per se than from reduced work to redirect the body COM. PMID:23580717

Mechanical and energetic consequences of rolling foot shape in human walking.

PubMed

Adamczyk, Peter G; Kuo, Arthur D

2013-07-15

During human walking, the center of pressure under the foot progresses forward smoothly during each step, creating a wheel-like motion between the leg and the ground. This rolling motion might appear to aid walking economy, but the mechanisms that may lead to such a benefit are unclear, as the leg is not literally a wheel. We propose that there is indeed a benefit, but less from rolling than from smoother transitions between pendulum-like stance legs. The velocity of the body center of mass (COM) must be redirected in that transition, and a longer foot reduces the work required for the redirection. Here we develop a dynamic walking model that predicts different effects from altering foot length as opposed to foot radius, and test it by attaching rigid, arc-like foot bottoms to humans walking with fixed ankles. The model suggests that smooth rolling is relatively insensitive to arc radius, whereas work for the step-to-step transition decreases approximately quadratically with foot length. We measured the separate effects of arc-foot length and radius on COM velocity fluctuations, work performed by the legs and metabolic cost. Experimental data (N=8) show that foot length indeed has much greater effect on both the mechanical work of the step-to-step transition (23% variation, P=0.04) and the overall energetic cost of walking (6%, P=0.03) than foot radius (no significant effect, P>0.05). We found the minimum metabolic energy cost for an arc foot length of approximately 29% of leg length, roughly comparable to human foot length. Our results suggest that the foot's apparently wheel-like action derives less benefit from rolling per se than from reduced work to redirect the body COM.

Comparison of Outcomes of Total Hip Arthroplasty between Patients with Ankylosing Spondylitis and Avascular Necrosis of the Femoral Head.

PubMed

Lee, Sun-Ho; Lee, Gun-Woo; Seol, Young-Jun; Park, Kyung-Soon; Yoon, Taek-Rim

2017-09-01

The objective of this study was to compare clinical and radiological outcomes of total hip arthroplasty (THA) between ankylosing spondylitis (AS) of the hip joint and avascular necrosis (AVN) of the femoral head. Thirty patients (30 hips) underwent cementless THA for AS between 2003 and 2012. They were compared to 30 patients (30 hips) who underwent the same procedure for AVN of the femoral head. Each group was matched for age and gender, and both groups had similar preoperative demographic characteristics. All cases were followed for minimum 4 postoperative years. Clinical evaluation was based on operation time, intraoperative blood loss, quantity of postoperative drainage, Harris Hip Score (HHS), and range of motion (ROM). Radiological results were evaluated by acetabular cup anteversion and inclination, femoral stem orientation, pre- and postoperative leg length discrepancy, and postoperative complications. The operation time was significantly longer in the AS group (120.2 ± 26.2 min) than in the AVN group (79.5 ± 11.1 min). The volume of postoperative drainage was significantly greater in the AS group (764.5 ± 355.4 mL vs. 510.5 ± 195.6 mL). Preoperative HHS was lower in the AS group (55.6 ± 13.8 vs. 59.2 ± 2.8). Similarly, postoperative HHS was significantly lower in the AS group (92.8 ± 2.7 vs. 97.4 ± 2.6). The arc of ROM was improved from 146.5° ± 13.2° preoperatively to 254.7° ± 17.2° postoperatively in the AS group and from 182.6° ± 15.5° to 260.4° ± 13.7° in the AVN group. Implant position and postoperative leg length discrepancy were not different between the groups. However, three cases of heterotopic ossification was observed in the AS group, whereas only 1 case was found in the AVN group. One deep infection and one aseptic stem loosening were found in the AS group, whereas none was observed in the AVN group. Cementless THA showed satisfactory clinical and radiological results in both groups, despite the longer operation time, larger blood loss volume, and lower HHS score of the AS group. Our findings suggest that cementless THA is an effective and reliable treatment for both AS and AVN.

Knee arthrodesis using a customised modular intramedullary nail in failed infected total knee arthroplasty.

PubMed

Putman, S; Kern, G; Senneville, E; Beltrand, E; Migaud, H

2013-06-01

Knee arthrodesis is used to treat patients with failed infected total knee arthroplasty (TKA). Among fixation methods, intramedullary nailing increases the chances of bone union but may carry a risk of infection around the nail. This risk is not well understood, because available case-series studies were not confined to patients with knee infection. Infection recurrence rates after knee arthrodesis with intramedullary nailing used to treat failed infected TKA are similar to those seen with other fixation methods. We retrospectively reviewed 31 cases of knee arthrodesis with fixation by a modular intramedullary nail performed at a subspecialized center treating complex osteoarticular infections (CRIOAC). The antibiotic regimen was determined based on multidisciplinary discussions and microbiological studies of preoperative and intraoperative specimens. Mean follow-up was 50 ± 22 months (range, 28-90 months). Arthrodesis was performed in one stage (n=6) or two stages (n=25). Success was defined as presence, after a postoperative follow-up of at least 24 months, based on the following criteria: normal erythrocyte sedimentation rate and/or C-reactive protein, no wound inflammation or sinus tract, no revision surgery, and no antibiotic treatment. Bone union was not a criterion for a successful arthrodesis procedure. Removal of the fixation material was required in three patients and long-term palliative antibiotic therapy in three patients (fixation material in place with repeated positive specimens) for a total of six failures due to infection (6/31, 19.4%). None of the patients experienced mechanical failure (no breakage of the material and no fixation failure of the nails designed to allow osteointegration). The mean leg length discrepancy was 10 ± 10 mm (range, 5-34 mm) and the mean Oxford score was 41 ± 11 (range, 23-58). The 50-month rate of arthrodesis survival to revision surgery for nail removal was 77.8 ± 4% and the 50-month rate of arthrodesis survival without revision surgery for persistent infection was 74.6 ± 4.2%. The infection recurrence rate was higher than with other fixation methods but remained acceptable (19.4%). Use of a modular intramedullary nail prevented major leg-length discrepancies, which are often poorly accepted by the patients, and allowed immediate weight bearing despite the often severe bone loss. Level IV, retrospective cohort study. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

The learning curve in short-stem THA: influence of the surgeon's experience on intraoperative adjustments due to intraoperative radiography.

PubMed

Loweg, Lennard; Kutzner, Karl Philipp; Trost, Matthias; Hechtner, Marlene; Drees, Philipp; Pfeil, Joachim; Schneider, Michael

2018-02-01

Short-stem THA has become increasingly popular over the last decade. However, implantation technique differs from conventional THA and thus possibly involves a distinct learning curve. The purpose of this study was to evaluate the value of intraoperative radiography and the influence of the surgeon's experience on intraoperative adjustments in short-stem THA. A total of 287 consecutive short-stem THAs, operated by a total of 24 senior consultants, consultants and residents in training, were prospectively included. Intraoperative radiography was performed after trial reduction. Preoperative planning and intraoperative outcome with regard to positioning, sizing of components as well as resulting offset and leg length were compared. Frequency, reason and type of intraoperative adjustments were documented in relation to the surgeon's experience. Operation time was assessed. One hundred and fifty-six (54.4%) procedures were carried out by one of three senior consultants, and a total of nine consultants and 12 residents in training performed 105 (36.6%) and 26 (9.0%) operations, respectively. In 121 cases (42.2%), intraoperative adjustments were made following intraoperative radiography. Intraoperative adjustments of one or more components were made by senior consultants in 51 cases (32.7%), by consultants in 53 cases (50.5%) and by residents in 17 cases (65.4%), respectively. The most common cause was undersizing of the stem. Operation time varied markedly between groups of surgeons. Short-stem THA involves a learning curve. Intraoperative radiography is decisive for prevention of malpositioning and undersizing of components, as well as loss of offset and leg length discrepancies. Hence, it should be considered mandatory, especially for less experienced surgeons.

Measuring Clearance Mechanics Based on Dynamic Leg Length

ERIC Educational Resources Information Center

Khamis, Sam; Danino, Barry; Hayek, Shlomo; Carmeli, Eli

2018-01-01

The aim of this study was to quantify clearance mechanics during gait. Seventeen children diagnosed with hemiplegic cerebral palsy underwent a three-dimensional gait analysis evaluation. Dynamic leg lengths were measured from the hip joint center to the heel, to the ankle joint center and to the forefoot throughout the gait cycle. Significant…

Does a crouched leg posture enhance running stability and robustness?

PubMed

Blum, Yvonne; Birn-Jeffery, Aleksandra; Daley, Monica A; Seyfarth, Andre

2011-07-21

Humans and birds both walk and run bipedally on compliant legs. However, differences in leg architecture may result in species-specific leg control strategies as indicated by the observed gait patterns. In this work, control strategies for stable running are derived based on a conceptual model and compared with experimental data on running humans and pheasants (Phasianus colchicus). From a model perspective, running with compliant legs can be represented by the planar spring mass model and stabilized by applying swing leg control. Here, linear adaptations of the three leg parameters, leg angle, leg length and leg stiffness during late swing phase are assumed. Experimentally observed kinematic control parameters (leg rotation and leg length change) of human and avian running are compared, and interpreted within the context of this model, with specific focus on stability and robustness characteristics. The results suggest differences in stability characteristics and applied control strategies of human and avian running, which may relate to differences in leg posture (straight leg posture in humans, and crouched leg posture in birds). It has been suggested that crouched leg postures may improve stability. However, as the system of control strategies is overdetermined, our model findings suggest that a crouched leg posture does not necessarily enhance running stability. The model also predicts different leg stiffness adaptation rates for human and avian running, and suggests that a crouched avian leg posture, which is capable of both leg shortening and lengthening, allows for stable running without adjusting leg stiffness. In contrast, in straight-legged human running, the preparation of the ground contact seems to be more critical, requiring leg stiffness adjustment to remain stable. Finally, analysis of a simple robustness measure, the normalized maximum drop, suggests that the crouched leg posture may provide greater robustness to changes in terrain height. Copyright © 2011 Elsevier Ltd. All rights reserved.

Leg Length Versus Torso Length in Pedophilia: Further Evidence of Atypical Physical Development Early in Life.

PubMed

Fazio, Rachel L; Dyshniku, Fiona; Lykins, Amy D; Cantor, James M

2017-08-01

Adult men's height results from an interaction among positive and negative influences, including genetic predisposition, conditions in utero, and influences during early development such as nutritional quality, pathogen exposure, and socioeconomic status. Decreased height, reflected specifically as a decreased leg length, is strongly associated with increased risk of poorer health outcomes. Although prior research has repeatedly shown that pedophiles are shorter than nonpedophiles, the largest study to date relied on self-reported height. In the present study, pedophiles demonstrated reduced measured height and reduced leg length as compared with teleiophiles. Given the prenatal and early childhood origins of height, these findings contribute additional evidence to a biological, developmental origin of pedophilia. In addition, the magnitude of this height difference was substantially larger than that found in children exposed to a variety of early environmental stressors, but similar to that seen in other biologically based neurodevelopmental disorders.

Selection on male size, leg length and condition during mate search in a sexually highly dimorphic orb-weaving spider.

PubMed

Foellmer, Matthias W; Fairbairn, Daphne J

2005-02-01

Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.

Bilateral differences in muscle fascicle architecture are not related to the preferred leg in jumping athletes.

PubMed

Aeles, Jeroen; Lenchant, Sietske; Vanlommel, Liesbeth; Vanwanseele, Benedicte

2017-07-01

In many sports, athletes have a preferred leg for sport-specific tasks, such as jumping, which leads to strength differences between both legs, yet the underlying changes in force-generating mechanical properties of the muscle remain unknown. The purpose of this study was to investigate whether the muscle architecture of the medial gastrocnemius (MG) is different between both legs in well-trained jumping athletes and untrained individuals. In addition, we investigated the effect of two ankle joint positions on ultrasound muscle architecture measurements. Muscle architecture of both legs was measured in 16 athletes and 11 untrained individuals at two ankle joint angles: one with the ankle joint in a tendon slack length (TSL) angle and one in a 90° angle. Fascicle lengths and pennation angles at TSL were not different between the preferred and non-preferred legs in either group. The comparison between groups showed no difference in fascicle length, but greater pennation angles were found in the athletes (21.7° ± 0.5°) compared to the untrained individuals (19.8° ± 0.6°). Analyses of the muscle architecture at a 90° angle yielded different results, mainly in the comparison between groups. These results provide only partial support for the notion of training-induced changes in muscle architecture as only differences in pennation angles were found between athletes and untrained individuals. Furthermore, our results provide support to the recommendation to take into account the tension-length relationship and to measure muscle architecture at individually determined tendon slack joint angles.

Risk factors associated with exertional medial tibial pain: a 12 month prospective clinical study

PubMed Central

Burne, S; Khan, K; Boudville, P; Mallet, R; Newman, P; Steinman, L; Thornton, E

2004-01-01

Objective: To investigate in a military setting the potential role of intrinsic biomechanical and anthropometric risk factors for, and the incidence of, exertional medial tibial pain (EMTP). Methods: A prospective clinical outcome study in a cohort of 122 men and 36 women at the Australian Defence Force Academy. Each cadet underwent measurements of seven intrinsic variables: hip range of motion, leg length discrepancy, lean calf girth, maximum ankle dorsiflexion range, foot type, rear foot alignment, and tibial alignment. Test–retest reliability was undertaken on each variable. A physician recorded any cadet presenting with diagnostic criteria of EMTP. Records were analysed at 12 months for EMTP presentation and for military fitness test results. Results: 23 cadets (12 men, 11 women) met the criteria for EMTP after 12 months, with a cross gender (F/M) odds ratio of 3.1. In men, both internal and external range of hip motion was greater in those with EMTP: left internal (12°, p = 0.000), right internal (8°, p = 0.014), left external (8°, p = 0.042), right external (9°, p = 0.026). Lean calf girth was lower by 4.2% for the right leg (p = 0.040) but by only 2.9% for the left leg (p = 0.141). No intrinsic risk factor was associated with EMTP in women. EMTP was the major cause for non-completion of the run component of the ADFA fitness test in both men and women. Conclusions: Greater internal and external hip range of motion and lower lean calf girth were associated with EMTP in male military cadets. Women had high rates of injury, although no intrinsic factor was identified. Reasons for this sex difference need to be identified. PMID:15273181

Risk factors associated with exertional medial tibial pain: a 12 month prospective clinical study.

PubMed

Burne, S G; Khan, K M; Boudville, P B; Mallet, R J; Newman, P M; Steinman, L J; Thornton, E

2004-08-01

To investigate in a military setting the potential role of intrinsic biomechanical and anthropometric risk factors for, and the incidence of, exertional medial tibial pain (EMTP). A prospective clinical outcome study in a cohort of 122 men and 36 women at the Australian Defence Force Academy. Each cadet underwent measurements of seven intrinsic variables: hip range of motion, leg length discrepancy, lean calf girth, maximum ankle dorsiflexion range, foot type, rear foot alignment, and tibial alignment. Test-retest reliability was undertaken on each variable. A physician recorded any cadet presenting with diagnostic criteria of EMTP. Records were analysed at 12 months for EMTP presentation and for military fitness test results. 23 cadets (12 men, 11 women) met the criteria for EMTP after 12 months, with a cross gender (F/M) odds ratio of 3.1. In men, both internal and external range of hip motion was greater in those with EMTP: left internal (12 degrees, p = 0.000), right internal (8 degrees, p = 0.014), left external (8 degrees, p = 0.042), right external (9 degrees, p = 0.026). Lean calf girth was lower by 4.2% for the right leg (p = 0.040) but by only 2.9% for the left leg (p = 0.141). No intrinsic risk factor was associated with EMTP in women. EMTP was the major cause for non-completion of the run component of the ADFA fitness test in both men and women. Greater internal and external hip range of motion and lower lean calf girth were associated with EMTP in male military cadets. Women had high rates of injury, although no intrinsic factor was identified. Reasons for this sex difference need to be identified.

Long-legged bees make adaptive leaps: linking adaptation to coevolution in a plant-pollinator network.

PubMed

Pauw, Anton; Kahnt, Belinda; Kuhlmann, Michael; Michez, Denis; Montgomery, Graham A; Murray, Elizabeth; Danforth, Bryan N

2017-09-13

Adaptation is evolution in response to natural selection. Hence, an adaptation is expected to originate simultaneously with the acquisition of a particular selective environment. Here we test whether long legs evolve in oil-collecting Rediviva bees when they come under selection by long-spurred, oil-secreting flowers. To quantify the selective environment, we drew a large network of the interactions between Rediviva species and oil-secreting plant species. The selective environment of each bee species was summarized as the average spur length of the interacting plant species weighted by interaction frequency. Using phylogenetically independent contrasts, we calculated divergence in selective environment and evolutionary divergence in leg length between sister species (and sister clades) of Rediviva We found that change in the selective environment explained 80% of evolutionary change in leg length, with change in body size contributing an additional 6% of uniquely explained variance. The result is one of four proposed steps in testing for plant-pollinator coevolution. © 2017 The Author(s).

The management of the neglected congenital foot deformity in the older child with the Taylor spatial frame.

PubMed

Hassan, Atef; Letts, Merv

2012-01-01

Neglected or inadequately treated rigid congenitally deformed feet in older children are a nightmarish challenge for the child, the parents, and the orthopaedic surgeon. Because of the multiplicity of spatial deformities exhibited by these feet and legs, it was hypothesized that correction using the Taylor spatial frame (TSF) would decrease morbidity, facilitate correction, and minimize treatment time in children from remote regions with extremely rigid deformed feet. Recent experience with the management of 11 such feet (Dimeglio type IV) in 9 children with an average age of 9.2 years using the TSF has been gratifying. Six children had associated leg length discrepancy, which was corrected by concomitant tibial lengthening. All feet underwent soft tissue releases, whereas forefoot and/or hindfoot osteotomies were performed in 7 feet. All children attained plantigrade, functional feet, and were fully ambulatory and capable of wearing normal footwear. Complications were minor consisting of pin tract infections, residual metatarsus varus in 3, and wound dehiscence in 1. There were no neurovascular events. This was attributed to the slower 3 plane correction using the TSF technique as well as the elimination of the need for plaster immobilization thus allowing direct monitoring of the foot and limb. The rigid foot deformity in the older child can be safely and effectively corrected with the aid of the TSF, which facilitates a 3 plane correction and concomitant limb lengthening.

The effect of Vitamin D and calcium plus Vitamin D on leg cramps in pregnant women: A randomized controlled trial.

PubMed

Mansouri, Ameneh; Mirghafourvand, Mojgan; Charandabi, Sakineh Mohammad Alizadeh; Najafi, Moslem

2017-01-01

This study intended to determine the effects of Vitamin D and calcium-Vitamin D in treating leg cramps in pregnant women. This study was conducted as a double-blind randomized controlled clinical trial on 126 participants, 18-35-year-old pregnant women with a minimum of two leg cramps per week who were referred to health-care centers in Tabriz-Iran in 2013. The participants were allocated to three 42 member groups using a randomized block design. For 42 days, the intervention groups took a 1000 unit Vitamin D pill or 300 mg calcium carbonate plus a 1000 unit Vitamin D pill, and the control group received a placebo pill every day. The participants were evaluated with regard to the frequency, length, and pain intensity of leg cramps during the week before and during the 3 rd and 6 th week of the intervention. The ANCOVA and repeated measurement test were used to analyze the data. Results showed that controlling for the effects before the intervention, calcium-Vitamin D, and Vitamin D supplements had no effect on the frequency, length, and pain intensity of leg cramps. The results of this study showed that the calcium-Vitamin D and the Vitamin D supplements have no effect on the frequency, length, and pain intensity of leg cramps during the 6 weeks of the study.

MID-VASTUS VS MEDIAL PARA-PATELLAR APPROACH IN TOTAL KNEE REPLACEMENT—TIME TO DISCHARGE

PubMed Central

Mukherjee, P.; Press, J.; Hockings, M.

2009-01-01

Background It has been shown before that when compared with the medial para-patellar approach, the mid-vastus approach for TKR results in less post-operative pain for patients and more rapid recovery of straight leg raise. As far as we are aware the post-operative length of stay of the two groups of patients has not been compared. We postulated that the reduced pain and more rapid recovery of straight leg raise would translate into an earlier, safe, discharge home for the mid-vastus patients compared with those who underwent a traditional medial para-patellar approach. Methods Twenty patients operated on by each of five established knee arthroplasty surgeons were evaluated prospectively with regard to their pre and post-operative range of movement, time to achieve straight leg raise post-operatively and length of post-operative hospital stay. Only one of the surgeons performed the mid-vastus approach, and the measurements were recorded by physiotherapists who were blinded as to the approach used on each patient. Results The results were analysed using a standard statistical software package, and although the mean length of stay was lower for the mid-vastus patients, the difference did not reach a level of significance (p = 0.13). The time taken to achieve straight leg raise post-operatively was significantly less in the mid-vastus group (p<0.001). Conclusion Although this study confirms previous findings that the mid-vastus approach reduces the time taken for patients to achieve straight leg raise, when compared with the medial para-patellar approach, on its own it does not translate into a significantly shorter length of hospital stay. In order to reduce the length of post-operative hospital stay with an accelerated rehabilitation program for TKR, a multi-disciplinary approach is required. Patient expectations, GP support, physiotherapists and nursing staff all have a role to play and the mid-vastus approach, in permitting earlier straight leg raising, significantly contributes to this. PMID:19742080

Static balance according to hip joint angle of unsupported leg during one-leg standing.

PubMed

Cha, Ju-Hyung; Kim, Jang-Joon; Ye, Jae-Gwan; Lee, Seul-Ji; Hong, Jeong-Mi; Choi, Hyun-Kyu; Choi, Ho-Suk; Shin, Won-Seob

2017-05-01

[Purpose] This study aimed to determine static balance according to hip joint angle of the unsupported leg during one-leg standing. [Subjects and Methods] Subjects included 45 healthy adult males and females in their 20s. During one-leg standing on the non-dominant leg, the position of the unsupported leg was classified according to hip joint angles of point angle was class. Static balance was then measured using a force plate with eyes open and closed. The total length, sway velocity, maximum deviation, and velocity on the mediolateral and anteroposterior axes of center of pressure were measured. [Results] In balance assessment with eyes open, there were significant differences between groups according to hip joint angle, except for maximum deviation on the anteroposterior axis. In balance assessment with eyes closed, there were significant differences between total length measurements at 0° and 30°, 60° and between 30° and 90°. There were significant differences between sway velocity measurements at 0° and 30° and between 30° and 90°. [Conclusion] Thus, there were differences in static balance according to hip joint angle. It is necessary to clearly identify the hip joint angle during one-leg standing testing.

A Critical Characteristic in the Transverse Galloping Pattern

PubMed Central

Wei, Xiaohui; Long, Yongjun; Wang, Chunlei; Wang, Shigang

2015-01-01

Transverse gallop is a common gait used by a large number of quadrupeds. This paper employs the simplified dimensionless quadrupedal model to discuss the underlying mechanism of the transverse galloping pattern. The model is studied at different running speeds and different values of leg stiffness, respectively. If the horizontal running speed reaches up to a critical value at a fixed leg stiffness, or if the leg stiffness reaches up to a critical value at a fixed horizontal speed, a key property would emerge which greatly reduces the overall mechanical forces of the dynamic system in a proper range of initial pitch angular velocities. Besides, for each horizontal speed, there is an optimal stiffness of legs that can reduce both the mechanical loads and the metabolic cost of transport. Furthermore, different body proportions and landing distance lags of a pair of legs are studied in the transverse gallop. We find that quadrupeds with longer length of legs compared with the length of the body are more suitable to employ the transverse galloping pattern, and the landing distance lag of a pair of legs could reduce the cost of transport and the locomotion frequency. PMID:27087773

Time kinetics of acute changes in muscle architecture in response to resistance exercise.

PubMed

Csapo, Robert; Alegre, Luis M; Baron, Ramon

2011-05-01

The study aimed to assess acute changes in muscle architecture and its recovery after exhaustive exercise. We hypothesised that repetitive leg press exercise would decrease vastus lateralis fascicle length, while increasing both muscle thickness and pennation angles. By investigating the time kinetics of recovery of these parameters, we wished to gain insight into the mechanisms responsible for muscle architectural changes during exercise. Muscle architecture was assessed in 41 male volunteers (25.2±3.7 yrs; 1.78±0.06 m; 76.4±11.7 kg) before and directly after, as well as 5, 10, 15, and 30 min after induction of fatigue by leg press exercise. Vastus lateralis muscle thickness, pennation angles and fascicle lengths were measured at rest by ultrasonography. Muscular fatigue was induced by an exhaustive series of maximum power, single leg press repetitions. Following leg press exercise vastus lateralis muscle thickness and pennation angles were increased by approximately 7 and 10%, whereas fascicle lengths decreased by 2%. Different recovery times (muscle thickness: 30 min; pennation angles: 15 min; fascicle lengths: 5 min) were observed. The differential time courses of recovery suggest that changes in muscle thickness, pennation angles, and fascicle lengths are driven by different exercise-related stimuli. Increased muscle perfusion and tendon creep are likely candidates accounting for short-term changes in muscle architecture. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Predicting a 10 repetition maximum for the free weight parallel squat using the 45 degrees angled leg press.

PubMed

Willardson, Jeffrey M; Bressel, Eadric

2004-08-01

The purpose of this research was to devise prediction equations whereby a 10 repetition maximum (10RM) for the free weight parallel squat could be predicted using the following predictor variables: 10RM for the 45 degrees angled leg press, body mass, and limb length. Sixty men were tested over a 3-week period, with 1 testing session each week. During each testing session, subjects performed a 10RM for the free weight parallel squat and 45 degrees angled leg press. Stepwise multiple regression analysis showed leg press mass lifted to be a significant predictor of squat mass lifted for both the advanced and the novice groups (p < 0.05). Leg press mass lifted accounted for approximately 25% of the variance in squat mass lifted for the novice group and 55% of the variance in squat mass lifted for the advanced group. Limb length and body mass were not significant predictors of squat mass lifted for either group. The following prediction equations were devised: (a) novice group squat mass = leg press mass (0.210) + 36.244 kg, (b) advanced group squat mass = leg press mass (0.310) + 19.438 kg, and (c) subject pool squat mass = leg press mass (0.354) + 2.235 kg. These prediction equations may save time and reduce the risk of injury when switching from the leg press to the squat exercise.

Incidence of foot rotation, pelvic crest unleveling, and supine leg length alignment asymmetry and their relationship to self-reported back pain.

PubMed

Knutson, Gary A

2002-02-01

To determine the incidence of pelvic unleveling, foot rotation, and supine leg length alignment asymmetry in a nonclinical population and to examine the validity (sensitivity, specificity, positive and negative predictive values) of these visual tests and their relationship to self-reported back pain. Volunteers answered a questionnaire regarding back pain and were then examined by a chiropractor who was unaware of the status of their back pain. Seventy-four unscreened volunteers answered the questionnaire. The association of visual tests with back pain and their validity indices; Visual Analogue Scale ratings. Fifty-one percent (n = 74) of volunteers examined had supine leg length alignment asymmetry (LLA). Pain intensity on a Visual Analogue Scale was significantly higher (P <.001) for those demonstrating supine LLA than for those without LLA. Those with back pain and recurrent back pain were significantly (P <.001) more likely to have supine LLA. The validity indices of the supine leg check showed acceptable levels for sensitivity (74%), specificity (78%), and positive predictive value (82%) [corrected] in recurrent back pain. Findings also indicated a high incidence of supine LLA in volunteers with chronic back pain (85%). The results indicated that, in this group of volunteers, the supine leg length alignment check had clinical validity as a stand-alone test for recurring back pain. Further testing on a larger, statistically defined cross-section of the population is recommended.

Parental smoking during pregnancy shortens offspring's legs.

PubMed

Żądzińska, E; Kozieł, S; Borowska-Strugińska, B; Rosset, I; Sitek, A; Lorkiewicz, W

2016-12-01

One of the most severe detrimental environmental factors acting during pregnancy is foetal smoke exposure. The aim of this study was to assess the effect of maternal, paternal and parental smoking during pregnancy on relative leg length in 7- to 10-year-old children. The research conducted in the years 2001-2002 included 978 term-born children, 348 boys and 630 girls, at the age of 7-10 years. Information concerning the birth weight of a child was obtained from the health records of the women. Information about the mother's and the father's smoking habits during pregnancy and about the mothers' education level was obtained from a questionnaire. The influence of parental smoking on relative leg length, controlled for age, sex, birth weight and the mother's education, as a proxy measure of socioeconomic status, and controlled for an interaction between sex and birth weight, was assessed by an analysis of covariance, where relative leg length was the dependent variable, smoking and sex were the independent variables, and birth weight as well as the mother's education were the covariates. Three separate analyses were run for the three models of smoking habits during pregnancy: the mother's smoking, the father's smoking and both parents' smoking. Only both parents' smoking showed a significant effect on relative leg length of offspring. It is probable that foetal hypoxia caused by carbon monoxide contained in smoke decelerated the growth of the long bones of foetuses. Copyright © 2016 Elsevier GmbH. All rights reserved.

Biomechanical influences on balance recovery by stepping.

PubMed

Hsiao, E T; Robinovitch, S N

1999-10-01

Stepping represents a common means for balance recovery after a perturbation to upright posture. Yet little is known regarding the biomechanical factors which determine whether a step succeeds in preventing a fall. In the present study, we developed a simple pendulum-spring model of balance recovery by stepping, and used this to assess how step length and step contact time influence the effort (leg contact force) and feasibility of balance recovery by stepping. We then compared model predictions of step characteristics which minimize leg contact force to experimentally observed values over a range of perturbation strengths. At all perturbation levels, experimentally observed step execution times were higher than optimal, and step lengths were smaller than optimal. However, the predicted increase in leg contact force associated with these deviations was substantial only for large perturbations. Furthermore, increases in the strength of the perturbation caused subjects to take larger, quicker steps, which reduced their predicted leg contact force. We interpret these data to reflect young subjects' desire to minimize recovery effort, subject to neuromuscular constraints on step execution time and step length. Finally, our model predicts that successful balance recovery by stepping is governed by a coupling between step length, step execution time, and leg strength, so that the feasibility of balance recovery decreases unless declines in one capacity are offset by enhancements in the others. This suggests that one's risk for falls may be affected more by small but diffuse neuromuscular impairments than by larger impairment in a single motor capacity.

Knee resection arthrodesis with allograft: a long-term follow-up study.

PubMed

Casadei, R; Donati, D; Ferraro, A; Giacomini, S; Gozzi, E; Gigli, M; Boni, F; Mercuri, M

2003-01-01

A consecutive series of 57 patients treated by knee resection arthrodesis for malignant or aggressive tumor around the knee was reviewed. Infection was present only after repeated surgery for other complications, delayed union or non-union occurred in 50% of the cases that could be evaluated, but were still easy to manage. Fracture incidence was higher than expected (32.6%) even occurring after 10 years; this was difficult to deal with and it often led to failure. The best possible method of fixation is still being debated, but locked nail and allograft cementation is often advised. Several satisfactory functional results were however achieved when surgery was performed in young patients; final results can be less satisfactory when there is leg length discrepancy and poor acceptance on the part of the patient. In recent years this type of surgery has been limited to younger male patients (10 to 14 years of age) in whom extra-articular knee resection was required or when most of the quadriceps muscle must be removed.

Image averaging of flexible fibrous macromolecules: the clathrin triskelion has an elastic proximal segment.

PubMed

Kocsis, E; Trus, B L; Steer, C J; Bisher, M E; Steven, A C

1991-08-01

We have developed computational techniques that allow image averaging to be applied to electron micrographs of filamentous molecules that exhibit tight and variable curvature. These techniques, which involve straightening by cubic-spline interpolation, image classification, and statistical analysis of the molecules' curvature properties, have been applied to purified brain clathrin. This trimeric filamentous protein polymerizes, both in vivo and in vitro, into a wide range of polyhedral structures. Contrasted by low-angle rotary shadowing, dissociated clathrin molecules appear as distinctive three-legged structures, called "triskelions" (E. Ungewickell and D. Branton (1981) Nature 289, 420). We find triskelion legs to vary from 35 to 62 nm in total length, according to an approximately bell-shaped distribution (mu = 51.6 nm). Peaks in averaged curvature profiles mark hinges or sites of enhanced flexibility. Such profiles, calculated for each length class, show that triskelion legs are flexible over their entire lengths. However, three curvature peaks are observed in every case: their locations define a proximal segment of systematically increasing length (14.0-19.0 nm), a mid-segment of fixed length (approximately 12 nm), and a rather variable end-segment (11.6-19.5 nm), terminating in a hinge just before the globular terminal domain (approximately 7.3 nm diameter). Thus, two major factors contribute to the overall variability in leg length: (1) stretching of the proximal segment and (2) stretching of the end-segment and/or scrolling of the terminal domain. The observed elasticity of the proximal segment may reflect phosphorylation of the clathrin light chains.

Falls in Korean Polio Survivors: Incidence, Consequences, and Risk Factors

PubMed Central

Lee, SeungYeol; Yang, Eun Joo; Kim, Keewon; Jung, Se Hee; Jang, Soong-Nang; Han, Soo Jeong; Kim, Wan-Ho

2016-01-01

Falls and fall-related injuries are important issue among polio survivors. The purpose of this study was to determine the incidence of, and consequences and factors associated with falls among Korean polio survivors. A total of 317 polio survivors participated in this study. All participants completed a questionnaire including fall history, symptoms related to post-polio syndrome and other information through a telephone interview. Among them, 80 participants visited our clinic for additional physical measurements and tests. Of the 317 respondents, 68.5% reported at least one fall in the past year. Of the fallers, 42.5% experienced at least one fall during one month. Most falls occurred during ambulation (76.6%), outside (75.2%) and by slipping down (29.7%). Of fallers, 45% reported any injuries caused by falls, and 23.3% reported fractures specifically. Female sex, old age, low bone mineral density, the presence of symptoms related to post-polio syndrome (PPS), poor balance confidence, short physical performance battery and weak muscle strength of knee extensor were not significantly associated with falls. Only leg-length discrepancy using spine-malleolar distance (SMD) was a significant factor associated with falls among Korean polio survivors. Our findings suggest that malalignment between the paralytic and non-paralytic limb length should be addressed in polio survivors for preventing falls. PMID:26839487

Derivation and application of a mathematical model for long bone growth.

PubMed

Seetharam, Suneil; Bhatia, Sujata K

2012-01-01

The objective of this work was to develop a mathematical model of long bone growth and to gain insights regarding growth disorders. A cell balance (mass balance of moving cells) assessment was performed on the three regions of the growth plate, to determine the variables (including number of proliferating cells, and division rate of proliferating cells) that influence tibia growth rate. Once this relationship was established, clinical data were used to understand how tibia growth rate and number of proliferating cells change with time. These equations were then inserted into the model to determine how cell division rate changes with time. The model was utilized to determine the influence of growth time, and to measure changes in vitamin C deficiency, Indian hedgehog (IHH) expression, and bone morphogenetic protein-2 (BMP-2) implants on tibia length. According to the model, a 10-month discrepancy in growth time between the two tibias is required to produce clinically significant leg asymmetry. In addition, vitamin C deficiency, IHH overexpression, and BMP-2 implants can all affect tibia length. These bioactive molecules have the greatest effect on tibia growth rate when these perturbations occur early in life for extended periods of time. The results are significant for modeling and predicting the effects of perturbations, including bioactive implants, on long bone growth.

Falls in Korean Polio Survivors: Incidence, Consequences, and Risk Factors.

PubMed

Nam, Ki Yeun; Lee, SeungYeol; Yang, Eun Joo; Kim, Keewon; Jung, Se Hee; Jang, Soong-Nang; Han, Soo Jeong; Kim, Wan-Ho; Lim, Jae-Young

2016-02-01

Falls and fall-related injuries are important issue among polio survivors. The purpose of this study was to determine the incidence of, and consequences and factors associated with falls among Korean polio survivors. A total of 317 polio survivors participated in this study. All participants completed a questionnaire including fall history, symptoms related to post-polio syndrome and other information through a telephone interview. Among them, 80 participants visited our clinic for additional physical measurements and tests. Of the 317 respondents, 68.5% reported at least one fall in the past year. Of the fallers, 42.5% experienced at least one fall during one month. Most falls occurred during ambulation (76.6%), outside (75.2%) and by slipping down (29.7%). Of fallers, 45% reported any injuries caused by falls, and 23.3% reported fractures specifically. Female sex, old age, low bone mineral density, the presence of symptoms related to post-polio syndrome (PPS), poor balance confidence, short physical performance battery and weak muscle strength of knee extensor were not significantly associated with falls. Only leg-length discrepancy using spine-malleolar distance (SMD) was a significant factor associated with falls among Korean polio survivors. Our findings suggest that malalignment between the paralytic and non-paralytic limb length should be addressed in polio survivors for preventing falls.

Three new Batillipes species (Arthrotardigrada: Batillipedidae) from the Brazilian coast.

PubMed

Santos, Erika; Rocha, Clélia M C DA; Gomes, Edivaldo Jr; Fontoura, Paulo

2017-03-16

Three new tardigrade species, Batillipes brasiliensis sp. nov., Batillipes dandarae sp. nov. and Batillipes potiguarensis sp. nov., are described from shallow subtidal sediments of the Brazilian coast. B. brasiliensis sp. nov. and B. dandarae sp. nov. have toes 3 and 4 on leg IV different in length, so they can be included in the D group of species, while B. potiguarensis sp. nov., with toes 3 and 4 on leg IV equal in length belong to the A group. Batillipes brasiliensis sp. nov. is characterized by having an ala-like caudal expansion; cuticular projections on the coxal region of legs I-III, and lateral projections. The lateral projection located between the third and fourth legs is fringed with digit-shaped expansions. Batillipes dandarae sp. nov. has a dorsal blunt enlargement in the scapular region; a pointed triangular caudal appendage, and no lateral projections. The new species exhibits a sensorial spine on legs I inserted posteriorly and turning forward, and anus surrounded by a peculiar cuticular structure constituted by six platelets. Batillipes potiguarensis sp. nov. is characterized by a unique combination of characters: scapular region well developed, protruding laterally at the level of the first pair of legs; lateral blunt processes between legs, and prominent roundish caudal protrusion. In addition, the new species exhibits cephalic appendages with swollen tips, evident secondary clavae, and very short sense organs on the legs IV.

Effects of milking stall dimensions on behavior of dairy cows during milking in different milking parlor types.

PubMed

Gómez, Y; Terranova, M; Zähner, M; Hillmann, E; Savary, P

2017-02-01

Dairy cow body size has increased over time because of breeding selection for higher milk yield, but milking stall dimensions have never been adjusted and are based on the practical experience of milking-machine manufacturers and advisory institutions. Narrow, limited milking stall dimensions might lead to behavioral changes during milking due to lack of comfort. The aim of this study was to examine the current space allowance in milking stalls on dairy farms and assess the effect of space allowance on cow behavior during milking. On 15 Swiss dairy farms, we measured clear milking stall dimensions and cow body dimensions. We calculated space ratios for length (SR length ) and width (SR width ) by dividing the milking stall length or width by cow body length or belly width, respectively. When the space ratio was >1, we assumed that the body length or width of cow was smaller than the milking stall length or width. On each farm, 10 healthy cows were chosen for behavioral observation during 1 evening milking. We recorded rumination, elimination, and latency to enter the milking stall by direct observation. Hind leg activity was recorded using acceleration loggers. Data were analyzed using general linear mixed-effects models with farm as a random effect. Due to a strong collinearity between SR width and SR length , we chose SR length for further analysis, because it is based on skeletal characteristics. The SR length was smallest in side-by-side parlors (1.07 ± 0.01) and largest in tandem parlors (1.18 ± 0.01). More cows had a tendency to ruminate with increasing SR length (odds ratio: 1.8). None of hind leg activity, maximum peaks of hind leg accelerations, or latency to enter the milking stall were significantly affected by SR length . Latency to enter the milking stall was longer for group milking parlors (side-by-side: 44.0 ± 3.2 s; herringbone: 34.3 ± 2.9 s) than for tandem parlors (19.0 ± 2.7 s). Milking parlor type had no effect on hind leg activity, maximum peaks of hind leg accelerations or rumination. The SR length affected rumination behavior to some extent, indicating that cow comfort was positively affected by larger milking stall length. Because cow comfort is important for good milking performance, further investigations of milking stall dimensions for cow comfort and thus welfare are needed. Furthermore, the results showed that parlor type affected cow behavior, irrespective of SR length , making future research necessary to identify the factors leading to this effect of parlor type. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Strategies for diagnosing leg oedema in primary care: a qualitative study of GPs' approaches.

PubMed

Diederich, Judith; Hartel, Simone; Baum, Erika; Bösner, Stefan

2014-12-01

The symptom leg oedema represents a broad range of possible underlying aetiologies. The background of leg oedema is multifactorial and usually the GP is the first contact point for patients presenting with this symptom. GPs rely on patient history and physical examination as their main diagnostic tools. To identify GPs' diagnostic approaches and heuristics in patients presenting with leg oedema. Interviews with 15 GPs (20-30 min) using a semi-structured interview-guideline were conducted. GPs described their individual diagnostic strategies concerning all patients presenting with leg oedema they had prospectively identified during the previous four weeks. Interviews were taped and transcribed verbatim. Qualitative analysis was conducted by two independent raters. GPs applied a variety of diagnostic approaches, which can be grouped in active and passive strategies. Active strategies comprised the use of decision rules and guidelines, Bayesian arguing, problem dichotomisation and discrepancy heuristics. Passive approaches included test of time, therapy as diagnosis, and taking patient assumptions into account. When dealing with leg oedema, GPs use prior information of individual patients in a specific way. There is a broad variety of diagnostic approaches that can be grouped in 'active' and 'passive' behaviour. Approaches mostly match with established diagnostic strategies in primary care.

Kinematics and Kinetics of Taekwon-do Side Kick

PubMed Central

Wąsik, Jacek

2011-01-01

The aim of the paper is to present an analysis of the influence of selected kinematic factors on the side kick technique. This issue is especially important in the traditional version of taekwon-do, in which a single strike may reveal the winner. Six taekwon-do (International Taekwon-do Federation) athletes were asked to participate in this case study. Generally accepted criteria of sports technique biomechanical analysis were adhered to. The athletes executed a side kick three times (in Taekwon-do terminology referred to as yop chagi) in a way which they use the kick in board breaking. The obtained data were used to determine the mean velocity changes in the function of relative extension length of the kicking leg. The maximum knee and foot velocities in the Cartesian coordinate system were determined. The leg lifting time and the duration of kick execution as well as the maximum force which the standing foot exerted on the ground were also determined. On the basis of the obtained values, mean values and standard deviations were calculated. The correlation dependence (r=0.72) shows that greater knee velocity affects the velocity which the foot develops as well as the fact that the total time of kick execution depends on the velocity which the knee (r = −0.59) and the foot (r = − 0.86) develop in the leg lifting phase. The average maximum speed was obtained at the length of the leg equal to 82% of the maximum length of the fully extended leg. This length can be considered the optimum value for achieving the maximum dynamics of the kick. PMID:23486086

Relationship between mechanical factors and incidence of low back pain.

PubMed

Nourbakhsh, Mohammad Reza; Arab, Amir Massoud

2002-09-01

A multifactorial cross-sectional nonexperimental design. To collectively investigate the association among 17 mechanical factors and occurrence of low back pain (LBP). Several physical characteristics, based on assumptions, clinical findings, and scientific experiments, have been associated with the development of LBP Controversy exists regarding the degree of association between some of these physical characteristics and LBP. Information regarding the degree of association of each factor to LBP is needed for effective prevention and appropriate treatment strategies. A total of 600 subjects participated in this study. Subjects were categorized into 4 groups: asymptomatic men (n = 150, age [mean +/- SD] = 43 +/- 15 years), asymptomatic women (n = 150, age [mean +/- SD] = 43 +/- 13 years), men with LBP (n = 150, age [mean +/- SD] = 43 +/- 14 years), and women with LBP (n = 150, age [mean +/- SD] = 43 +/- 13 years). Seventeen physical characteristics were measured in each group and the relative association of each characteristic with LBP was assessed. Among all the factors tested, endurance of the back extensor muscles had the highest association with LBP Other factors such as the length of the back extensor muscles, and the strength of the hip flexor, hip adductor, and abdominal muscles also had a significant association with LBP. It appears that muscle endurance and weakness are associated with LBP and that structural factors such as the size of the lumbar lordosis, pelvic tilt, leg length discrepancy, and the length of abdominal, hamstring, and iliopsoas muscles are not associated with the occurrence of LBP.

THE DIFFUSION LENGTH OF THERMAL NEUTRONS IN PORTLAND CONCRETE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dugdale, R.A.; Healy, E.

1957-10-01

A measurement of the diffusion length of thermal neutrons in Portland concrete, originally raade by Salmon two years previously, has been repeated. An apparent decrease from 7.04 cm to 6.61 cm has oocurred. This change, which is only four times the standard deviation of the result, could be due to a small increase in water content. In assessing the amount required, a discrepancy between calculated and measured diffusion length was found. Possible explanations of the discrepancy are discussed. (auth)

Childhood circumstances and anthropometry: the Boyd Orr cohort.

PubMed

Whitley, Elise; Gunnell, David; Davey Smith, George; Holly, Jeff M P; Martin, Richard M

2008-01-01

Childhood environment is known to affect stature in childhood and adulthood. Peak growth for different anthropometric measures occurs at different times and so associations with childhood conditions that vary across different components of stature may indicate periods of growth that are particularly influenced by environmental factors. The study examined relationships between anthropometric measurements (foot length, shoulder breadth, height, trunk and leg length) and childhood exposures (breast-feeding, birth order, household income, household food expenditure, social class, crowding, number of children in the household, and household diet) in 2376 members of the Boyd Orr cohort aged 2-14 years. All childhood exposures were associated with childhood anthropometric measures to some degree. In multivariable models, the most consistent relationships were positive associations of anthropometric measures with ever being breast-fed, decreasing number of children in the household and, in boys, increasing household income. There was a steadily decreasing gradient in the strength of associations across different anthropometric measures; the strongest were observed with height followed by leg length, foot length, trunk and shoulder breadth. The individual components of stature most strongly associated with childhood environment in this age group were leg and foot length.

[LIMB LENGH SHORTENING AFTER ARTERIAL CANNULATION IN INFANCY].

PubMed

Díaz-Ben, B; Balvís-Balvís, P; Lozano-Balseiro, M; González-Herranz, P

2016-01-01

The aim of this study was to assess the relationship between arterial cannulations and the development of limb length discrepancies in childhood or impaired growth of the proximal femur. A retrospective study was conducted on 300 children who required arterial cannulation and/or cardiac catheterisation during childhood in relation to congenital heart diseases. Seven of these patients were referred from the Paediatric Cardiology clinic due to a limb length discrepancy and/or proximal femoral deformities. Seven children, with a mean age of 10 years, were referred to our clinic. The mean length discrepancy was 2.7cm, and was more frequent on the right side. Three of the patients presented with proximal femoral deformities: two cases of caput valgum and one of bilateral physeal arrest of the greater trochanter. All children were initially treated with a shoe lift in the shortest limb. One of them required a tibial lengthening and two others are awaiting a similar procedure. We recommend clinical and radiological follow-up of patients who have undergone catheterisation during their infancy due to the relationship between these techniques and the risk of developing a limb length discrepancy. Copyright © 2015 SECOT. Published by Elsevier Espana. All rights reserved.

Exploring the relationship between stride, stature and hand size for forensic assessment.

PubMed

Guest, Richard; Miguel-Hurtado, Oscar; Stevenage, Sarah; Black, Sue

2017-11-01

Forensic evidence often relies on a combination of accurately recorded measurements, estimated measurements from landmark data such as a subject's stature given a known measurement within an image, and inferred data. In this study a novel dataset is used to explore linkages between hand measurements, stature, leg length and stride. These three measurements replicate the type of evidence found in surveillance videos with stride being extracted from an automated gait analysis system. Through correlations and regression modelling, it is possible to generate accurate predictions of stature from hand size, leg length and stride length (and vice versa), and to predict leg and stride length from hand size with, or without, stature as an intermediary variable. The study also shows improved accuracy when a subject's sex is known a-priori. Our method and models indicate the possibility of calculating or checking relationships between a suspect's physical measurements, particularly when only one component is captured as an accurately recorded measurement. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Skipping on uneven ground: trailing leg adjustments simplify control and enhance robustness.

PubMed

Müller, Roy; Andrada, Emanuel

2018-01-01

It is known that humans intentionally choose skipping in special situations, e.g. when descending stairs or when moving in environments with lower gravity than on Earth. Although those situations involve uneven locomotion, the dynamics of human skipping on uneven ground have not yet been addressed. To find the reasons that may motivate this gait, we combined experimental data on humans with numerical simulations on a bipedal spring-loaded inverted pendulum model (BSLIP). To drive the model, the following parameters were estimated from nine subjects skipping across a single drop in ground level: leg lengths at touchdown, leg stiffness of both legs, aperture angle between legs, trailing leg angle at touchdown (leg landing first after flight phase), and trailing leg retraction speed. We found that leg adjustments in humans occur mostly in the trailing leg (low to moderate leg retraction during swing phase, reduced trailing leg stiffness, and flatter trailing leg angle at lowered touchdown). When transferring these leg adjustments to the BSLIP model, the capacity of the model to cope with sudden-drop perturbations increased.

Asymmetry in Determinants of Running Speed During Curved Sprinting.

PubMed

Ishimura, Kazuhiro; Sakurai, Shinji

2016-08-01

This study investigates the potential asymmetries between inside and outside legs in determinants of curved running speed. To test these asymmetries, a deterministic model of curved running speed was constructed based on components of step length and frequency, including the distances and times of different step phases, takeoff speed and angle, velocities in different directions, and relative height of the runner's center of gravity. Eighteen athletes sprinted 60 m on the curved path of a 400-m track; trials were recorded using a motion-capture system. The variables were calculated following the deterministic model. The average speeds were identical between the 2 sides; however, the step length and frequency were asymmetric. In straight sprinting, there is a trade-off relationship between the step length and frequency; however, such a trade-off relationship was not observed in each step of curved sprinting in this study. Asymmetric vertical velocity at takeoff resulted in an asymmetric flight distance and time. The runners changed the running direction significantly during the outside foot stance because of the asymmetric centripetal force. Moreover, the outside leg had a larger tangential force and shorter stance time. These asymmetries between legs indicated the outside leg plays an important role in curved sprinting.

Posture alteration as a measure to accommodate uneven ground in able-bodied gait

PubMed Central

Blickhan, Reinhard; Muller, Roy; Rode, Christian

2017-01-01

Though the effects of imposed trunk posture on human walking have been studied, less is known about such locomotion while accommodating changes in ground level. For twelve able participants, we analyzed kinematic parameters mainly at touchdown and toe-off in walking across a 10-cm visible drop in ground level (level step, pre-perturbation step, step-down, step-up) with three postures (regular erect, ~30° and ~50° of trunk flexion from the vertical). Two-way repeated measures ANOVAs revealed step-specific effects of posture on the kinematic behavior of gait mostly at toe-off of the pre-perturbation step and the step-down as well as at touchdown of the step-up. In preparation to step-down, with increasing trunk flexion the discrepancy in hip−center of pressure distance, i.e. effective leg length, (shorter at toe-off versus touchdown), compared with level steps increased largely due to a greater knee flexion at toe-off. Participants rotated their trunk backwards during step-down (2- to 3-fold backwards rotation compared with level steps regardless of trunk posture) likely to control the angular momentum of their whole body. The more pronounced trunk backwards rotation in trunk-flexed walking contributed to the observed elevated center of mass (CoM) trajectories during the step-down which may have facilitated drop negotiation. Able-bodied individuals were found to recover almost all assessed kinematic parameters comprising the vertical position of the CoM, effective leg length and angle as well as hip, knee and ankle joint angles at the end of the step-up, suggesting an adaptive capacity and hence a robustness of human walking with respect to imposed trunk orientations. Our findings may provide clinicians with insight into a kinematic interaction between posture and locomotion in uneven ground. Moreover, a backward rotation of the trunk for negotiating step-down may be incorporated into exercise-based interventions to enhance gait stability in individuals who exhibit trunk-flexed postures during walking. PMID:29281712

On the Biomimetic Design of Agile-Robot Legs

PubMed Central

Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

2011-01-01

The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented. PMID:22247667

On the biomimetic design of agile-robot legs.

PubMed

Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

2011-01-01

The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

Locomotor variation and bending regimes of capuchin limb bones.

PubMed

Demes, Brigitte; Carlson, Kristian J

2009-08-01

Primates are very versatile in their modes of progression, yet laboratory studies typically capture only a small segment of this variation. In vivo bone strain studies in particular have been commonly constrained to linear locomotion on flat substrates, conveying the potentially biased impression of stereotypic long bone loading patterns. We here present substrate reaction forces (SRF) and limb postures for capuchin monkeys moving on a flat substrate ("terrestrial"), on an elevated pole ("arboreal"), and performing turns. The angle between the SRF vector and longitudinal axes of the forearm or leg is taken as a proxy for the bending moment experienced by these limb segments. In both frontal and sagittal planes, SRF vectors and distal limb segments are not aligned, but form discrepant angles; that is, forces act on lever arms and exert bending moments. The positions of the SRF vectors suggest bending around oblique axes of these limb segments. Overall, the leg is exposed to greater moments than the forearm. Simulated arboreal locomotion and turns introduce variation in the discrepancy angles, thus confirming that expanding the range of locomotor behaviors studied will reveal variation in long bone loading patterns that is likely characteristic of natural locomotor repertoires. "Arboreal" locomotion, even on a linear noncompliant branch, is characterized by greater variability of force directions and discrepancy angles than "terrestrial" locomotion (significant for the forearm only), partially confirming the notion that life in trees is associated with greater variation in long bone loading. Directional changes broaden the range of external bending moments even further.

The Influence of Added Mass on Optimal Step Length in Running.

PubMed

Reenalda, Jasper; Maas, Maurice T F; de Koning, Jos J

2016-10-01

To examine the influence of induced changes in the morphology of the leg by adding mass on the optimal step length (OSL) in experienced runners to get more insight into parameters that influence preferred step length (PSL) and OSL. Thirteen experienced male runners (mean age 26.9 ± 6.1 y, height 183.7 ± 7.1 cm, mass 71.8 ± 5.9 kg) ran on a treadmill in 3 different conditions: unloaded (UL), loaded with 2 kg mass at the ankles (MA), and loaded with 2 kg mass at the hips (MH) at 7 different step lengths (SLs). SL deviations were expressed as deviations in relative leg length (%LL) from the individual PSL: 0%LL, ±5%LL, ±10%LL, and ±15%LL. Trials lasted 8 min, and 8 min of rest was given between trials. Oxygen uptake (V̇O 2 ) was expressed as a fraction of V̇O 2 at PSL + 0%LL in the unloaded condition (%V̇O 2 ). The %SL with the lowest value of %V̇O 2 was considered the OSL for this group of participants. OSL at the UL condition was 6% shorter than PSL. The MA condition resulted in a 7%LL larger OSL than at UL and MH (P < .05). The mass distribution of the leg is a determinant of the OSL. As a consequence of the added mass to the ankles, OSL was 7%LL longer. Morphological characteristics of the leg might therefore play an important role in determining the runner's individual optimal SL.

The Effect of Commonly Performed Exercises on the Levator Hiatus Area and the Length and Strength of Pelvic Floor Muscles in Postpartum Women.

PubMed

Siff, Lauren N; Hill, Audra J; Walters, Samantha J; Walters, Ginny; Walters, Mark D

2018-05-02

The aim oft his study was to compare the effects of 10 common exercises to traditional pelvic floor muscle (PFM) contractions (Kegel) on levator hiatus (LH) area and PFM length and strength. This is a cross-sectional study of 15 healthy postpartum women. Ten exercises were studied. These were common variations of leg, core, and back exercises used in yoga, Pilates, strength training, and physical therapy. Each participant performed all 10 exercises at a single visit in 2 examination settings: transperineal ultrasound and perineometry. Ultrasound measured the LH area and PFM length, and perineometry measured the muscle strength (peak squeeze pressure). Kegel generates an increase in squeeze pressure (24.3 cm H2O), shortens the muscles (-0.46 cm) and narrows the LH (-0.13 cm). The bird-dog and plank exercises were not different from Kegel in any measurement. While the leg-lift ultrasound dimensions are similar to Kegel, leg lifts generated peak squeeze pressures stronger than any other exercise (including Kegel). Whereas ultrasound dimensions were similar to Kegel, tucked and untucked squats and thigh adductions generated weaker contractions than Kegel. While crunch generated a squeeze pressure similar to Kegel, the ultrasound dimensions showed a significantly wider LH and longer muscle than Kegel. Bridge, clam, and plié exercises affected the PFMs differently than Kegel in all measures. Bird-dog, plank, and leg-lift exercises should be evaluated as alternative exercises to Kegel as they affect PFM strength and length and LH area similarly to Kegel, and leg lifts generate a stronger contraction than Kegel.

Discriminant musculo-skeletal leg characteristics between sprint and endurance elite Caucasian runners.

PubMed

Bex, T; Iannaccone, F; Stautemas, J; Baguet, A; De Beule, M; Verhegghe, B; Aerts, P; De Clercq, D; Derave, W

2017-03-01

Excellence in either sprinting or endurance running requires specific musculo-skeletal characteristics of the legs. This study aims to investigate the morphology of the leg of sprinters and endurance runners of Caucasian ethnicity. Eight male sprinters and 11 male endurance runners volunteered to participate in this cross-sectional study. They underwent magnetic resonance imaging and after data collection, digital reconstruction was done to calculate muscle volumes and bone lengths. Sprinters have a higher total upper leg volume compared to endurance runners (7340 vs 6265 cm 3 ). Specifically, the rectus femoris, vastus lateralis, and hamstrings showed significantly higher muscle volumes in the sprint group. For the lower leg, only a higher muscle volume was found in the gastrocnemius lateralis for the sprinters. No differences were found in muscle volume distribution, center of mass in the different muscles, or relative bone lengths. There was a significant positive correlation between ratio hamstrings/quadriceps volume and best running performance in the sprint group. Sprinters and endurance runners of Caucasian ethnicity showed the greatest distinctions in muscle volumes, rather than in muscle distributions or skeletal measures. Sprinters show higher volumes in mainly the proximal and lateral leg muscles than endurance runners. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Kinematic and EMG Responses to Pelvis and Leg Assistance Force during Treadmill Walking in Children with Cerebral Palsy

PubMed Central

Kim, Janis; Arora, Pooja; Zhang, Yunhui

2016-01-01

Treadmill training has been used for improving locomotor function in children with cerebral palsy (CP), but the functional gains are relatively small, suggesting a need to improve current paradigms. The understanding of the kinematic and EMG responses to forces applied to the body of subjects during treadmill walking is crucial for improving current paradigms. The objective of this study was to determine the kinematics and EMG responses to the pelvis and/or leg assistance force. Ten children with spastic CP were recruited to participate in this study. A controlled assistance force was applied to the pelvis and/or legs during stance and swing phase of gait through a custom designed robotic system during walking. Muscle activities and spatial-temporal gait parameters were measured at different loading conditions during walking. In addition, the spatial-temporal gait parameters during overground walking before and after treadmill training were also collected. Applying pelvis assistance improved step height and applying leg assistance improved step length during walking, but applying leg assistance also reduced muscle activation of ankle flexor during the swing phase of gait. In addition, step length and self-selected walking speed significantly improved after one session of treadmill training with combined pelvis and leg assistance. PMID:27651955

[Analysis of the results of bone healing in femurs lengthened by the gradual distraction method in children and adolescents].

PubMed

Jochymek, J; Skvaril, J; Ondrus, S

2009-10-01

Treatment of leg length inequality via lengthening of the shorter extremity is an infrequent orthopedic procedure due to the requirement of special distraction devices and possible serious complications. Essential qualitative changes in operative technique development are associated with the name of G. A. Ilizarov, who paved the way for the autoregenerate gradual distraction method in the 1950s. In the years 1990 through 2007 a total of 67 patients underwent femur lengthening via gradual distraction using various types of external fixators at the Department of Pediatric Surgery, Orthopedics, and Traumatology, Faculty Hospital in Brno. The quality of bone healing was monitored and a number of parameters followed and statistically evaluated using regularly scheduled X-ray examinations. In 13 cases we had to remove the external fixator following the distraction phase, perform an osteosynthesis via a splint and fill the distraction gap via spongioplasty. The bone healing was satisfactory in the remaining 54 patients and the lengthened bone required no other fixation method. The analysis showed statistically significant deceleration in bone healing following distraction in female patients over 12 years of age, and in boys over 14 years of age. Lack of periosteal callus five weeks after surgery always signified serious problems in further healing. Severe complications were recorded in 11 cases during the distraction phase, and in 12 cases after the removal of the distraction apparatus. Our results fully correspond with the data and experience of others cited authors. In addition our study showed deceleration in bone healing in girls over 12 years and in boys over 14 years of age and serious problem in healing when is lack of periostal callus five weeks after surgery. The aim of this report was to present the results of our study of distraction gap bone healing using the gradual lengthening approach. Key words: leg lengthening, gradual distraction, external fixation, leg discrepancy, complication.

Tendon length and joint flexibility are related to running economy.

PubMed

Hunter, Gary R; Katsoulis, Konstantina; McCarthy, John P; Ogard, William K; Bamman, Marcas M; Wood, David S; Den Hollander, Jan A; Blaudeau, Tamilane E; Newcomer, Bradley R

2011-08-01

The purpose of study was to determine whether quadriceps/patella and Achilles tendon length and flexibility of the knee extensors and plantar flexors are related to walking and running economy. Twenty-one male distance runners were subjects. Quadriceps/patella and Achilles tendon length were measured by magnetic resonance imaging; body composition was measured DXA; oxygen uptake at rest while seated, walking (3 mph), and running (6 and 7 mph) were measured by indirect calorimetry; knee and ankle joint flexibility were measured by goniometry; and leg lengths were measured by anthropometry while seated. Correlations were used to identify relationships between variables of interest. Net VO2 (exercise VO2 - rest VO2) for walking (NVOWK) and running at 6 and 7 mph (NVO6 and NVO7, respectively) was significantly related to Achilles tendon length (r varying from -0.40 to -0.51, P all < 0.04). Achilles tendon cross section was not related to walking or running economy. Quadriceps/patella tendon length was significantly related to NVO7 (r = -0.43, P = 0.03) and approached significance for NVO6 (r = -0.36, P = 0.06). Flexibility of the plantar flexors was related to NVO7 (+0.38, P = 0.05). Multiple regression showed that Achilles tendon length was independently related to NVO6 and NVO7 (partial r varying from -0.53 to -0.64, all P < 0.02) independent of lower leg length, upper leg length, quadriceps/patella tendon length, knee extension flexibility, or plantarflexion flexibility. These data support the premise that longer lower limb tendons (especially Achilles tendon) and less flexible lower limb joints are associated with improved running economy.

Tibial lengthening over humeral and tibial intramedullary nails in patients with sequelae of poliomyelitis: a comparative study.

PubMed

Chen, Daoyun; Chen, Jianmin; Jiang, Yao; Liu, Fanggang

2011-06-01

Leg discrepancy is common after poliomyelitis. Tibial lengthening is an effective way to solve this problem. It is believed lengthening over a tibial intramedullary nail can provide a more comfortable lengthening process than by the conventional technique. However, patients with sequelae of poliomyelitis typically have narrow intramedullary canals allowing limited space for inserting a tibial intramedullary nail and Kirschner wires. To overcome this problem, we tried using humeral nails instead of tibial nails in the lengthening procedure. In this study, we used humeral nails in 20 tibial lengthening procedures and compared the results with another group of patients who were treated with tibial lengthening over tibial intramedullary nails. The mean consolidation index, percentage of increase and external fixation index did not show significant differences between the two groups. However, less blood loss and shorter operating time were noted in the humeral nail group. More patients encountered difficulty with the inserted intramedullary nail in the tibial nail group procedure. The complications did not show a statistically significant difference between the two techniques on follow-up. In conclusion, we found the humeral nail lengthening technique was more suitable in leg discrepancy patients with sequelae of poliomyelitis.

Rural–urban variations in age at menarche, adult height, leg-length and abdominal adiposity in black South African women in transitioning South Africa

PubMed Central

2018-01-01

Abstract Background: The pre-pubertal socioeconomic environment may be an important determinant of age at menarche, adult height, body proportions and adiposity: traits closely linked to adolescent and adult health. Aims: This study explored differences in age at menarche, adult height, relative leg-length and waist circumference between rural and urban black South African young adult women, who are at different stages of the nutrition and epidemiologic transitions. Subjects and methods: We compared 18–23 year-old black South African women, 482 urban-dwelling from Soweto and 509 from the rural Mpumalanga province. Age at menarche, obstetric history and household socio-demographic and economic information were recorded using interview-administered questionnaires. Height, sitting-height, hip and waist circumference were measured using standardised techniques. Results: Urban and rural black South African women differed in their age at menarche (at ages 12.7 and 14.5 years, respectively). In urban women, a one-year increase in age at menarche was associated with a 0.65 cm and 0.16% increase in height and relative leg-length ratio, respectively. In both settings, earlier age at menarche and shorter relative leg-length were independently associated with an increase in waist circumference. Conclusions: In black South African women, the earlier onset of puberty, and consequently an earlier growth cessation process, may lead to central fat mass accumulation in adulthood. PMID:29557678

Dissociation between running economy and running performance in elite Kenyan distance runners.

PubMed

Mooses, Martin; Mooses, Kerli; Haile, Diresibachew Wondimu; Durussel, Jérôme; Kaasik, Priit; Pitsiladis, Yannis Paul

2015-01-01

The purpose of this study was to investigate the relationship between running economy (RE) and performance in a homogenous group of competitive Kenyan distance runners. Maximal aerobic capacity (VO2max) (68.8 ± 3.8 ml∙kg(-1)∙min(-1)) was determined on a motorised treadmill in 32 Kenyan (25.3 ± 5.0 years; IAAF performance score: 993 ± 77 p) distance runners. Leg anthropometry was assessed and moment arm of the Achilles tendon determined. While Achilles moment arm was associated with better RE (r(2) = 0.30, P = 0.003) and upper leg length, total leg length and total leg length to body height ratio were correlated with running performance (r = 0.42, P = 0.025; r = 0.40, P = 0.030 and r = 0.38, P = 0.043, respectively), RE and maximal time on treadmill (t(max)) were not associated with running performance (r = -0.01, P = 0.965; r = 0.27; P = 0.189, respectively) in competitive Kenyan distance runners. The dissociation between RE and running performance in this homogenous group of runners would suggest that RE can be compensated by other factors to maintain high performance levels and is in line with the idea that RE is only one of many factors explaining elite running performance.

[Problems and complications of leg lengthening with the Wagner apparatus].

PubMed

Herzog, R; Hefti, F

1992-06-01

Since 1971, we have performed 189 leg lengthening procedures using the Wagner method at our institution. The results obtained in the first 26 cases (1971-1973) showed a high complication rate, which led us to reconsider the indications for this procedure. In the present paper, we analyze the results of 37 leg lengthening procedures carried out in 32 patients during the last 10 years (1981-1990) in the children's unit of the orthopedic department of the University of Basle. We found a complication rate of 78%, and in 46% of cases there was more than one major complication. We did not distinguish between "complications" and "problems", because such distinctions are of little importance to the patient. The average age at the time of surgery was 14.8 years, and the average increase in length was 4.3 (2.2-9.2) cm. For each 1 cm of lengthening, an average of 21 days in hospital and 64 days of reduced weight-bearing were needed. Our conclusion is that the Wagner method makes it possible to attain the goal of leg lengthening, but the second step cannot reduce the length of stay in hospital or the length of time the patient needs the help of crutches. Bone remodeling is disturbed. Our preliminary experience with the Ilizarov method is more encouraging.

Influences of the extensor portion of the gluteus maximus muscle on pelvic tilt before and after the performance of a fatigue protocol.

PubMed

Alvim, Felipe C; Peixoto, Jennifer G; Vicente, Eduardo J D; Chagas, Paula S C; Fonseca, Diogo S

2010-01-01

There is a lack of data in the literature for determining the influences of the extensor portion of the gluteus maximus muscle on pelvic tilting and, thus, on lumbar stability. To assess the influences of the extensor portion of the gluteus maximus muscle on pelvic tilt. Ten healthy young subjects were recruited, with a body mass index (BMI) below 24.9 kg/m(2) and leg length discrepancy below 1 cm. The BMI, pelvic perimeter and lower-limb lengths were assessed and, subsequently, the degrees of hemi-pelvic tilt and asymmetry between them were analyzed using lateral view photographs of the subjects in a standing position, using SAPO (Software for Postural Assessment). Next, fatigue was induced in the extensor portion of the gluteus maximus muscle on the dominant side, and after that the hemi-pelvic tilt and the asymmetry between the hemi-pelvises were reassessed. The Pearson r and Student t tests were conducted at the significance level of alpha=0.05. There were no significant correlations between the confounding variables and asymmetry of the hemi-pelvic angles. There were significant changes in the hemi-pelvic angle of the dominant side (t=3.760; p=0.004). Fatigue in the extensor portion of the gluteus maximus muscle can generate increases in the tilt angle of the ipsilateral pelvis.

Exaggerated male legs increase mating success by reducing disturbance to females in the cave wētā Pachyrhamma waitomoensis.

PubMed

Fea, Murray; Holwell, Gregory I

2018-06-13

Mate guarding is a widespread behaviour resulting from sperm competition and conflict over optimal remating rates. It is a key way in which males exhibit differential mating investment, and represents a complex interplay between mating effort, intrasexual competition, opportunity costs and sexual conflict. Nevertheless, although there are many examples of exaggerated male structures used to fight rivals, few animals have developed specialized male morphological adaptations for directly sheltering females from disturbance by non-rivals. Here we report on the use of sexually dimorphic, elongated male hind legs, which are used to guard females in the New Zealand cave wētā Pachyrhamma waitomoensis (Orthoptera: Rhaphidophoridae). We found that male hind legs alongside the female failed to deter rivals from accessing her or disrupting copulation. However, they did reduce the disturbance to females from other, non-rival animals such as juveniles and heterospecifics. Males with longer hind legs were more effective in reducing disturbance, and remained with females for longer. Longer guarding periods also led to higher numbers of matings between pairs. Models of males with artificially altered hind leg dimensions also showed a benefit to greater leg length, and artificially altering the disturbance rate to females also had a significant effect on pair duration. Our results indicate that nuisance disturbance to females may play an important role in driving sexual selection on male leg length and its exaggeration in this species. © 2018 The Author(s).

Cost and quality implications of discrepancies between admitting and discharge diagnoses.

PubMed

McNutt, Robert; Johnson, Tricia; Kane, Jason; Ackerman, Mariel; Odwazny, Richard; Bardhan, Jaydeep

2012-01-01

Presenting and discharge diagnoses of hospitalized patients may differ as a result of patient complexity, diagnostic dilemmas, or errors in clinical judgment at the time of primary assessment. When diagnoses at admission and discharge are not in agreement, this discrepancy may indicate more complex processes of care and resultant costs. It is unclear whether surrogate measures reflecting quality of care are impacted by discrepant diagnoses. To assess whether an association exists between admitting and discharge International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes and other quality markers including hospital length of stay, total cost of care, and 30-day readmission rate. This was a retrospective, cross-sectional analysis of general internal medicine patients aged 18 years and older. Diagnosis discrepancy was defined as a difference between the 3-digit ICD-9 diagnosis code at admission and the principal 3-digit ICD-9 diagnosis code at discharge. Sixty-eight percent of patients had a diagnosis discrepancy. Diagnosis discrepancy was associated with a 0.41-day increase in length of stay (P < .001), $663 increase in direct costs (P < .001), and a 1.55 times greater odds of readmission within 30 days (P < .001). Diagnosis discrepancy was associated with hospital quality outcome measures. This finding likely reflects variations in patients' diagnostic complexity.

Early-life nutritional status and metabolic syndrome: gender-specific associations from a cross-sectional analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

Briskiewicz, Bruna Lucas; Barreto, Sandhi Maria; do Amaral, Joana Ferreira; Diniz, Maria de Fátima Haueisen Sander; Molina, Maria Del Carmen Bisi; Matos, Sheila Maria Alvim; Cardoso, Letícia de Oliveira; Velasquez-Melendez, Gustavo; Schmidt, Maria Inês; Giatti, Luana

2018-06-01

In the present study we investigated gender-specific associations of low birth weight (LBW) and shorter relative leg length with metabolic syndrome (MetS) after adjusting for sociodemographic characteristics and health-related behaviours. We also investigated whether these associations are independent of age at menarche and BMI at 20 years old. Cross-sectional analysis. Baseline data from 12 602 participants (35-74 years) of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), 2008-2010. MetS was defined according to the revised National Cholesterol Education Program Adult Treatment Panel III guidelines. LBW (<2·5 kg) and age- and sex-standardized relative leg length (high, medium and low) were the explanatory variables studied. The strength of the associations between the explanatory variables and MetS was estimated by Poisson regression with robust variance. MetS prevalence was 34·2 %; it was more prevalent in men (36·8 %) than in women (32·2 %). In multivariate analysis, LBW was associated (prevalence ratio; 95 % CI) with MetS only in women (1·28; 1·24, 1·45). Shorter leg length was associated with MetS in both men (1·21; 1·09, 1·35 and 1·46; 1·29, 1·65 for low and medium lengths, respectively) and women (1·12; 1·00, 1·25 and 1·40; 1·22, 1·59 for low and medium lengths, respectively). Additional adjustments for age at menarche and BMI at 20 years old did not change the associations. Poor nutritional status as estimated by LBW and lower leg length in childhood was associated with a higher prevalence of MetS, although LBW was a significant factor only among women.

Pilot study of the impact that bilateral sacroiliac joint manipulation using a drop table technique has on gait parameters in asymptomatic individuals with a leg length inequality.

PubMed

Ward, John; Sorrels, Ken; Coats, Jesse; Pourmoghaddam, Amir; Deleon, Carlos; Daigneault, Paige

2014-03-01

The purpose of this study was to pilot test our study procedures and estimate parameters for sample size calculations for a randomized controlled trial to determine if bilateral sacroiliac (SI) joint manipulation affects specific gait parameters in asymptomatic individuals with a leg length inequality (LLI). Twenty-one asymptomatic chiropractic students engaged in a baseline 90-second walking kinematic analysis using infrared Vicon® cameras. Following this, participants underwent a functional LLI test. Upon examination participants were classified as: left short leg, right short leg, or no short leg. Half of the participants in each short leg group were then randomized to receive bilateral corrective SI joint chiropractic manipulative therapy (CMT). All participants then underwent another 90-second gait analysis. Pre- versus post-intervention gait data were then analyzed within treatment groups by an individual who was blinded to participant group status. For the primary analysis, all p-values were corrected for multiple comparisons using the Bonferroni method. Within groups, no differences in measured gait parameters were statistically significant after correcting for multiple comparisons. The protocol of this study was acceptable to all subjects who were invited to participate. No participants refused randomization. Based on the data collected, we estimated that a larger main study would require 34 participants in each comparison group to detect a moderate effect size.

Biomechanical pole and leg characteristics during uphill diagonal roller skiing.

PubMed

Lindinger, Stefan Josef; Göpfert, Caroline; Stöggl, Thomas; Müller, Erich; Holmberg, Hans-Christer

2009-11-01

Diagonal skiing as a major classical technique has hardly been investigated over the last two decades, although technique and racing velocities have developed substantially. The aims of the present study were to 1) analyse pole and leg kinetics and kinematics during submaximal uphill diagonal roller skiing and 2) identify biomechanical factors related to performance. Twelve elite skiers performed a time to exhaustion (performance) test on a treadmill. Joint kinematics and pole/plantar forces were recorded separately during diagonal roller skiing (9 degrees; 11 km/h). Performance was correlated to cycle length (r = 0.77; P < 0.05), relative leg swing (r = 0.71), and gliding time (r = 0.74), hip flexion range of motion (ROM) during swing (r = 0.73) and knee extension ROM during gliding (r = 0.71). Push-off demonstrated performance correlations for impulse of leg force (r = 0.84), relative duration (r= -0.76) and knee flexion (r = 0.73) and extension ROM (r = 0.74). Relative time to peak pole force was associated with performance (r = 0.73). In summary, diagonal roller skiing performance was linked to 1) longer cycle length, 2) greater impulse of force during a shorter push-off with larger flexion/extension ROMs in leg joints, 3) longer leg swing, and 4) later peak pole force, demonstrating the major key characteristics to be emphasised in training.

Leg extensor muscle strength, postural stability, and fear of falling after a 2-month home exercise program in women with severe knee joint osteoarthritis.

PubMed

Rätsepsoo, Monika; Gapeyeva, Helena; Sokk, Jelena; Ereline, Jaan; Haviko, Tiit; Pääsuke, Mati

2013-01-01

BACKGROUND AND OBJECTIVE. The aim of this study was to compare the leg extensor muscle strength, the postural stability, and the fear of falling in the women with severe knee joint osteoarthritis (OA) before and after a 2-month home exercise program (HEP). MATERIAL AND METHODS. In total, 17 women aged 46-72 years with late-stage knee joint OA scheduled for total knee arthroplasty participated in this study before and after the 2-month HEP with strengthening, stretching, balance, and step exercises. The isometric peak torque (PT) of the leg extensors and postural stability characteristics when standing on a firm or a foam surface for 30 seconds were recorded. The fear of falling and the pain intensity (VAS) were estimated. RESULTS. A significant increase in the PT and the PT-to-body weight (PT-to-BW) ratio of the involved leg as well as the bilateral PT and the PT-to-BW ratio was found after the 2-month HEP compared with the data before the HEP (P<0.05). The PT and the PT-to-BW ratio of the involved leg were significantly lower compared with the uninvolved leg before the HEP (P<0.05). The center of the pressure sway length (foam surface) decreased significantly after the HEP (P<0.05). Significant correlations were found between the PT of the involved leg and the bilateral PT and the fear of falling and between the PT of the involved leg and the postural sway (foam surface) before the HEP. CONCLUSIONS. After the 2-month HEP, the leg extensor muscle strength increased and the postural sway length on a foam surface decreased. The results indicate that the increased leg extensor muscle strength improves postural stability and diminishes the fear of falling in women with late-stage knee joint OA.

Muscle and Myotendinous Tissue Properties at the Distal Tibia as Assessed by High-Resolution Peripheral Quantitative Computed Tomography.

PubMed

Erlandson, M C; Wong, A K O; Szabo, E; Vilayphiou, N; Zulliger, M A; Adachi, J D; Cheung, A M

High-resolution peripheral quantitative computed tomography (HR-pQCT) quantifies bone microstructure and density at the distal tibia where there is also a sizable amount of myotendinous (muscle and tendon) tissue (M T ); however, there is no method for the quantification of M T . This study aimed (1) to assess the feasibility of using HR-pQCT distal tibia scans to estimate M T properties using a custom algorithm, and (2) to determine the relationship between M T properties at the distal tibia and mid-leg muscle density (MD) obtained from pQCT. Postmenopausal women from the Hamilton cohort of the Canadian Multicenter Osteoporosis Study had a single-slice (2.3 ± 0.5 mm) 66% site pQCT scan measuring muscle cross-sectional area (MCSA) and MD. A standard HR-pQCT scan was acquired at the distal tibia. HR-pQCT-derived M T cross-sectional area (M T CSA) and M T density (M T D) were calculated using a custom algorithm in which thresholds (34.22-194.32 mg HA/cm 3 ) identified muscle seed volumes and were iteratively expanded. Pearson and Bland-Altman plots were used to assess correlations and systematic differences between pQCT- and HR-pQCT-derived muscle properties. Among 45 women (mean age: 74.6 ± 8.5 years, body mass index: 25.9 ± 4.3 kg/m 2 ), M T D was moderately correlated with mid-leg MD across the 2 modalities (r = 0.69-0.70, p < 0.01). Bland-Altman analyses revealed no evidence of directional bias for M T D-MD. HR-pQCT and pQCT measures of M T CSA and MCSA were moderately correlated (r = 0.44, p < 0.01). Bland-Altman plots for M T CSA revealed that larger MCSAs related to larger discrepancy between the distal and the mid-leg locations. This is the first study to assess the ability of HR-pQCT to measure M T size, density, and morphometry. HR-pQCT-derived M T D was moderately correlated with mid-leg MD from pQCT. This relationship suggests that distal M T may share common properties with muscle throughout the length of the leg. Future studies will assess the value of HR-pQCT-derived M T properties in the context of falls, mobility, and balance. Copyright © 2016 International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Numerical analysis of finite Debye-length effects in induced-charge electro-osmosis.

PubMed

Gregersen, Misha Marie; Andersen, Mathias Baekbo; Soni, Gaurav; Meinhart, Carl; Bruus, Henrik

2009-06-01

For a microchamber filled with a binary electrolyte and containing a flat unbiased center electrode at one wall, we employ three numerical models to study the strength of the resulting induced-charge electro-osmotic (ICEO) flow rolls: (i) a full nonlinear continuum model resolving the double layer, (ii) a linear slip-velocity model not resolving the double layer and without tangential charge transport inside this layer, and (iii) a nonlinear slip-velocity model extending the linear model by including the tangential charge transport inside the double layer. We show that, compared to the full model, the slip-velocity models significantly overestimate the ICEO flow. This provides a partial explanation of the quantitative discrepancy between observed and calculated ICEO velocities reported in the literature. The discrepancy increases significantly for increasing Debye length relative to the electrode size, i.e., for nanofluidic systems. However, even for electrode dimensions in the micrometer range, the discrepancies in velocity due to the finite Debye length can be more than 10% for an electrode of zero height and more than 100% for electrode heights comparable to the Debye length.

Perception of Saudi dentists and lay people to altered smile esthetics.

PubMed

Talic, Nabeel; Alomar, Samar; Almaidhan, Asma

2013-01-01

To evaluate and compare the perceptions of Saudi dentists and lay people to altered smile features. Thirty-six digital smile photographs with altered features were used. Altered features included the following: crown length, width, gingival level of the lateral incisors, gingival display, midline diastema, and upper midline shift. The photographs were presented to a sample of 30 dentists and 30 lay people with equal gender distribution. Each participant rated each picture with a visual analogue scale, which ranged from 0 (very unattractive) to 100 (very attractive). Dentists were more critical than lay people when evaluating symmetrical crown length discrepancies. Compared to lay people, Saudi dentists gave lower ratings to a crown length discrepancy of >2 mm (P < 0.001), crown width discrepancy of ⩾2 mm (P < 0.05), change in gingiva to lip distance of ⩾2 mm (P < 0.01), and midline deviation of >1 mm (P < 0.01). There was no significant difference between dentists and lay people towards alterations in the gingival level of the lateral incisors or towards a space between the central incisors. No significant sex difference was seen across the groups. In this sample, Saudi dentists gave significantly lower attractiveness scores to crown length and crown width discrepancies, midline deviations, and changes in gingiva to lip distance compared to Saudi lay people.

Evaluation of arm-leg coordination in flat breaststroke.

PubMed

Chollet, D; Seifert, L; Leblanc, H; Boulesteix, L; Carter, M

2004-10-01

This study proposes a new method to evaluate arm-leg coordination in flat breaststroke. Five arm and leg stroke phases were defined with a velocity-video system. Five time gaps quantified the time between arm and leg actions during three paces of a race (200 m, 100 m and 50 m) in 16 top level swimmers. Based on these time gaps, effective glide, effective propulsion, effective leg insweep and effective recovery were used to identify the different stroke phases of the body. A faster pace corresponded to increased stroke rate, decreased stroke length, increased propulsive phases, shorter glide phases, and a shorter T1 time gap, which measured the effective body glide. The top level swimmers showed short time gaps (T2, T3, T4, measuring the timing of arm-leg recoveries), which reflected the continuity in arm and leg actions. The measurement of these time gaps thus provides a pertinent evaluation of swimmers' skill in adapting their arm-leg coordination to biomechanical constraints.

Insect-computer hybrid legged robot with user-adjustable speed, step length and walking gait.

PubMed

Cao, Feng; Zhang, Chao; Choo, Hao Yu; Sato, Hirotaka

2016-03-01

We have constructed an insect-computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g., gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e., applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. © 2016 The Author(s).

Insect–computer hybrid legged robot with user-adjustable speed, step length and walking gait

PubMed Central

Cao, Feng; Zhang, Chao; Choo, Hao Yu

2016-01-01

We have constructed an insect–computer hybrid legged robot using a living beetle (Mecynorrhina torquata; Coleoptera). The protraction/retraction and levation/depression motions in both forelegs of the beetle were elicited by electrically stimulating eight corresponding leg muscles via eight pairs of implanted electrodes. To perform a defined walking gait (e.g. gallop), different muscles were individually stimulated in a predefined sequence using a microcontroller. Different walking gaits were performed by reordering the applied stimulation signals (i.e. applying different sequences). By varying the duration of the stimulation sequences, we successfully controlled the step frequency and hence the beetle's walking speed. To the best of our knowledge, this paper presents the first demonstration of living insect locomotion control with a user-adjustable walking gait, step length and walking speed. PMID:27030043

Tooth-size discrepancy: A comparison between manual and digital methods

PubMed Central

Correia, Gabriele Dória Cabral; Habib, Fernando Antonio Lima; Vogel, Carlos Jorge

2014-01-01

Introduction Technological advances in Dentistry have emerged primarily in the area of diagnostic tools. One example is the 3D scanner, which can transform plaster models into three-dimensional digital models. Objective This study aimed to assess the reliability of tooth size-arch length discrepancy analysis measurements performed on three-dimensional digital models, and compare these measurements with those obtained from plaster models. Material and Methods To this end, plaster models of lower dental arches and their corresponding three-dimensional digital models acquired with a 3Shape R700T scanner were used. All of them had lower permanent dentition. Four different tooth size-arch length discrepancy calculations were performed on each model, two of which by manual methods using calipers and brass wire, and two by digital methods using linear measurements and parabolas. Results Data were statistically assessed using Friedman test and no statistically significant differences were found between the two methods (P > 0.05), except for values found by the linear digital method which revealed a slight, non-significant statistical difference. Conclusions Based on the results, it is reasonable to assert that any of these resources used by orthodontists to clinically assess tooth size-arch length discrepancy can be considered reliable. PMID:25279529

Scaling of avian bipedal locomotion reveals independent effects of body mass and leg posture on gait.

PubMed

Daley, Monica A; Birn-Jeffery, Aleksandra

2018-05-22

Birds provide an interesting opportunity to study the relationships between body size, limb morphology and bipedal locomotor function. Birds are ecologically diverse and span a large range of body size and limb proportions, yet all use their hindlimbs for bipedal terrestrial locomotion, for at least some part of their life history. Here, we review the scaling of avian striding bipedal gaits to explore how body mass and leg morphology influence walking and running. We collate literature data from 21 species, spanning a 2500× range in body mass from painted quail to ostriches. Using dynamic similarity theory to interpret scaling trends, we find evidence for independent effects of body mass, leg length and leg posture on gait. We find no evidence for scaling of duty factor with body size, suggesting that vertical forces scale with dynamic similarity. However, at dynamically similar speeds, large birds use relatively shorter stride lengths and higher stride frequencies compared with small birds. We also find that birds with long legs for their mass, such as the white stork and red-legged seriema, use longer strides and lower swing frequencies, consistent with the influence of high limb inertia on gait. We discuss the observed scaling of avian bipedal gait in relation to mechanical demands for force, work and power relative to muscle actuator capacity, muscle activation costs related to leg cycling frequency, and considerations of stability and agility. Many opportunities remain for future work to investigate how morphology influences gait dynamics among birds specialized for different habitats and locomotor behaviors. © 2018. Published by The Company of Biologists Ltd.

Leg Stiffness in Female Soccer Players: Intersession Reliability and the Fatiguing Effects of Soccer-Specific Exercise.

PubMed

De Ste Croix, Mark B A; Hughes, Jonathan D; Lloyd, Rhodri S; Oliver, Jon L; Read, Paul J

2017-11-01

De Ste Croix, MBA, Hughes, JD, Lloyd, RS, Oliver, JL, and Read, PJ. Leg stiffness in female soccer players: intersession reliability and the fatiguing effects of soccer-specific exercise. J Strength Cond Res 31(11): 3052-3058, 2016-Low levels of leg stiffness and reduced leg stiffness when fatigue is present compromise physical performance and increase injury risk. The purpose of this study was to (a) determine the reliability of leg stiffness measures obtained from contact mat data and (b) explore age-related differences in leg stiffness after exposure to a soccer-specific fatigue protocol in young female soccer players. Thirty-seven uninjured female youth soccer players divided into 3 subgroups based on chronological age (under 13 [U13], under 15 [U15], and under 17 [U17] year-olds) volunteered to participate in the study. After baseline data collection, during which relative leg stiffness, contact time, and flight time were collected, participants completed an age-appropriate soccer-specific fatigue protocol (SAFT). Upon completion of the fatigue protocol, subjects were immediately retested. Intersession reliability was acceptable and could be considered capable of detecting worthwhile changes in performance. Results showed that leg stiffness decreased in the U13 year-olds, was maintained in the U15 age group, and increased in the U17 players. Contact times and flight times did not change in the U13 and U15 year-olds, but significantly decreased and increased, respectively, in the U17 age group. The data suggest that age-related changes in the neuromuscular control of leg stiffness are present in youth female soccer players. Practitioners should be aware of these discrepancies in neuromuscular responses to soccer-specific fatigue, and should tailor training programs to meet the needs of individuals, which may subsequently enhance performance and reduce injury risk.

The use of biocultural data in interpreting sex differences in body proportions among rural Amazonians

PubMed Central

VERCELLOTTI, GIUSEPPE; PIPERATA, BARBARA A.

2012-01-01

Variation in height and body proportions is relatively well understood at the inter-population level, but less is known about intra-population variation. This study explores intra-population variation in body proportions among 172 (88 female; 84 male) adult rural Amazonians. We test the hypotheses that: 1) stunting is associated with changes in proportions and fatness; 2) the sexes express different proportions in response to similar environmental stress and 3) female growth is negatively affected by the costs of reproduction. We examined height, sitting height and total leg length in subsamples based on sex and nutritional status (stunted/non-stunted) in relation to biocultural factors including access to food and healthcare and female reproductive history parameters. Differences in proportions were examined using the Quick-Test (Tsutakawa and Hewett, 1977); correlation analyses were employed to detect associations between anthropometric data and body fatness, and female reproductive history parameters. We found significantly higher rates of stunting among females (X2=5.31; p=0.02; RR=1.4). Stunted individuals exhibited relatively shorter legs than non-stunted individuals (p=0.02), although this was not found in within-sex analyses. A significant negative correlation was found between leg length index and fatness (p<0.01). Lastly, females exhibited relatively shorter legs than males (p=0.0003) and, among females, height and leg length were significantly positively correlated with age-at-first-birth (p<0.02) suggesting that adolescent pregnancy may negatively affect growth in this population. Our findings provide insights for the study of intra-population variation in body proportions and highlight the importance of biocultural data in interpreting the pattern of variation observed in living and past populations. PMID:22120650

The use of biocultural data in interpreting sex differences in body proportions among rural Amazonians.

PubMed

Vercellotti, Giuseppe; Piperata, Barbara A

2012-01-01

Variation in height and body proportions is relatively well-understood at the inter-population level, but less is known about intra-population variation. This study explores intra-population variation in body proportions among 172 (88 female; 84 male) adult rural Amazonians. We test the hypotheses that: (1) stunting is associated with changes in proportions and fatness; (2) the sexes express different proportions in response to similar environmental stress; and (3) female growth is negatively affected by the costs of reproduction. We examined height, sitting height, and total leg length in subsamples based on sex and nutritional status (stunted/nonstunted) in relation to biocultural factors including access to food and healthcare and female reproductive history parameters. Differences in proportions were examined using the Quick-Test (Tsutakawa and Hewett: Biometrics 33 (1977) 215-219); correlation analyses were used to detect associations between anthropometric data and body fatness, and female reproductive history parameters. We found significantly higher rates of stunting among females (X(2) = 5.31; P = 0.02; RR = 1.4). Stunted individuals exhibited relatively shorter legs than nonstunted individuals (P = 0.02), although this was not found in within-sex analyses. A significant negative correlation was found between leg length index and fatness (P < 0.01). Lastly, females exhibited relatively shorter legs than males (P = 0.0003) and, among females, height and leg length were significantly positively correlated with age-at-first-birth (P < 0.02) suggesting that adolescent pregnancy may negatively affect growth in this population. Our findings provide insights for the study of intra-population variation in body proportions and highlight the importance of biocultural data in interpreting the pattern of variation observed in living and past populations. Copyright © 2011 Wiley Periodicals, Inc.

Muscular strategy shift in human running: dependence of running speed on hip and ankle muscle performance.

PubMed

Dorn, Tim W; Schache, Anthony G; Pandy, Marcus G

2012-06-01

Humans run faster by increasing a combination of stride length and stride frequency. In slow and medium-paced running, stride length is increased by exerting larger support forces during ground contact, whereas in fast running and sprinting, stride frequency is increased by swinging the legs more rapidly through the air. Many studies have investigated the mechanics of human running, yet little is known about how the individual leg muscles accelerate the joints and centre of mass during this task. The aim of this study was to describe and explain the synergistic actions of the individual leg muscles over a wide range of running speeds, from slow running to maximal sprinting. Experimental gait data from nine subjects were combined with a detailed computer model of the musculoskeletal system to determine the forces developed by the leg muscles at different running speeds. For speeds up to 7 m s(-1), the ankle plantarflexors, soleus and gastrocnemius, contributed most significantly to vertical support forces and hence increases in stride length. At speeds greater than 7 m s(-1), these muscles shortened at relatively high velocities and had less time to generate the forces needed for support. Thus, above 7 m s(-1), the strategy used to increase running speed shifted to the goal of increasing stride frequency. The hip muscles, primarily the iliopsoas, gluteus maximus and hamstrings, achieved this goal by accelerating the hip and knee joints more vigorously during swing. These findings provide insight into the strategies used by the leg muscles to maximise running performance and have implications for the design of athletic training programs.

Changes in running kinematics, kinetics, and spring-mass behavior over a 24-h run.

PubMed

Morin, Jean-Benoît; Samozino, Pierre; Millet, Guillaume Y

2011-05-01

This study investigated the changes in running mechanics and spring-mass behavior over a 24-h treadmill run (24TR). Kinematics, kinetics, and spring-mass characteristics of the running step were assessed in 10 experienced ultralong-distance runners before, every 2 h, and after a 24TR using an instrumented treadmill dynamometer. These measurements were performed at 10 km·h, and mechanical parameters were sampled at 1000 Hz for 10 consecutive steps. Contact and aerial times were determined from ground reaction force (GRF) signals and used to compute step frequency. Maximal GRF, loading rate, downward displacement of the center of mass, and leg length change during the support phase were determined and used to compute both vertical and leg stiffness. Subjects' running pattern and spring-mass behavior significantly changed over the 24TR with a 4.9% higher step frequency on average (because of a significantly 4.5% shorter contact time), a lower maximal GRF (by 4.4% on average), a 13.0% lower leg length change during contact, and an increase in both leg and vertical stiffness (+9.9% and +8.6% on average, respectively). Most of these changes were significant from the early phase of the 24TR (fourth to sixth hour of running) and could be speculated as contributing to an overall limitation of the potentially harmful consequences of such a long-duration run on subjects' musculoskeletal system. During a 24TR, the changes in running mechanics and spring-mass behavior show a clear shift toward a higher oscillating frequency and stiffness, along with lower GRF and leg length change (hence a reduced overall eccentric load) during the support phase of running. © 2011 by the American College of Sports Medicine

Physiological cross-sectional area of human leg muscles based on magnetic resonance imaging

NASA Technical Reports Server (NTRS)

Fukunaga, T.; Roy, R. R.; Shellock, F. G.; Hodgson, J. A.; Day, M. K.; Lee, P. L.; Kwong-Fu, H.; Edgerton, V. R.

1992-01-01

Magnetic resonance imaging techniques were used to determine the physiological cross-sectional areas (PCSAs) of the major muscles or muscle groups of the lower leg. For 12 healthy subjects, the boundaries of each muscle or muscle group were digitized from images taken at 1-cm intervals along the length of the leg. Muscle volumes were calculated from the summation of each anatomical CSA (ACSA) and the distance between each section. Muscle length was determined as the distance between the most proximal and distal images in which the muscle was visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length:muscle length ratios were used to estimate fiber lengths. The mean volumes of the major plantarflexors were 489, 245, and 140 cm3 for the soleus and medial (MG) and lateral (LG) heads of the gastrocnemius. The mean PCSA of the soleus was 230 cm2, about three and eight times larger than the MG (68 cm2) and LG (28 cm2), respectively. These PCSA values were eight (soleus), four (MG), and three (LG) times larger than their respective maximum ACSA. The major dorsiflexor, the tibialis anterior (TA), had a muscle volume of 143 cm2, a PCSA of 19 cm2, and an ACSA of 9 cm2. With the exception of the soleus, the mean fiber length of all subjects was closely related to muscle volume across muscles. The soleus fibers were unusually short relative to the muscle volume, thus potentiating its force potential.(ABSTRACT TRUNCATED AT 250 WORDS).

Nutritional status of Maya children, their mothers, and their grandmothers residing in the City of Merida, Mexico: revisiting the leg-length hypothesis.

PubMed

Azcorra, Hugo; Varela-Silva, Maria Inês; Rodriguez, Luis; Bogin, Barry; Dickinson, Federico

2013-01-01

To test the hypothesis that leg length-relative-to-stature is a more sensitive indicator of nutrition and health than is total height (HT) or sitting height (SH) in a sample of 109 triads of urban Maya children (6.0-8.99 years), their mothers, and maternal grandmothers from Merida, Mexico. From September 2011 to June 2012, the following factors were obtained from all participants: (1) HT, SH, and leg length (LL); (2) the sitting height ratio (SHR = [SH × 100]/HT), relative leg length index (RLLI = [LL × 100]/height), and percentiles and z-scores of HT, SH, and LL were calculated; and (3) the percentages of stunting for children or very short ZHT for the adults, short ZSH, and short ZLL: HT-for-age, SH-for-age, or LL-for-age below the 5th percentile of the reference were calculated. Correlations were performed to examine the association between z-scores of HT, SH, and LL among three generations. Stunting in children was 11% (short ZLL = 29%, short ZSH = 7%). Short ZHT was present in 71% of mothers (short ZLL = 54%, short ZSH = 50%) and 90% of grandmothers (short ZLL = 69%, short ZSH = 83%). Significant correlations in ZHT, ZSH, and ZLL were found in mother-to-child and grandmother-to-mother, with the strongest correlations for ZLL. These findings support the hypothesis for children and mothers. Based on ZLL, there is evidence that childhood and nutrition have improved somewhat for each younger generation. Persistent environmental adversity during growth resulted in growth deficits for LL and SH for the mothers and grandmothers. Copyright © 2013 Wiley Periodicals, Inc.

An asymptotic solution to a passive biped walker model

NASA Astrophysics Data System (ADS)

Yudaev, Sergey A.; Rachinskii, Dmitrii; Sobolev, Vladimir A.

2017-02-01

We consider a simple model of a passive dynamic biped robot walker with point feet and legs without knee. The model is a switched system, which includes an inverted double pendulum. Robot’s gait and its stability depend on parameters such as the slope of the ramp, the length of robot’s legs, and the mass distribution along the legs. We present an asymptotic solution of the model. The first correction to the zero order approximation is shown to agree with the numerical solution for a limited parameter range.

Decreasing initial telomere length in humans intergenerationally understates age-associated telomere shortening

PubMed Central

Holohan, Brody; De Meyer, Tim; Batten, Kimberly; Mangino, Massimo; Hunt, Steven C; Bekaert, Sofie; De Buyzere, Marc L; Rietzschel, Ernst R; Spector, Tim D; Wright, Woodring E; Shay, Jerry W

2015-01-01

Telomere length shortens with aging, and short telomeres have been linked to a wide variety of pathologies. Previous studies suggested a discrepancy in age-associated telomere shortening rate estimated by cross-sectional studies versus the rate measured in longitudinal studies, indicating a potential bias in cross-sectional estimates. Intergenerational changes in initial telomere length, such as that predicted by the previously described effect of a father’s age at birth of his offspring (FAB), could explain the discrepancy in shortening rate measurements. We evaluated whether changes occur in initial telomere length over multiple generations in three large datasets and identified paternal birth year (PBY) as a variable that reconciles the difference between longitudinal and cross-sectional measurements. We also clarify the association between FAB and offspring telomere length, demonstrating that this effect is substantially larger than reported in the past. These results indicate the presence of a downward secular trend in telomere length at birth over generational time with potential public health implications. PMID:25952108

Tibial Lengthening: Extraarticular Calcaneotibial Screw to Prevent Ankle Equinus

PubMed Central

Belthur, Mohan V.; Paley, Dror; Jindal, Gaurav; Burghardt, Rolf D.; Specht, Stacy C.

2008-01-01

Between 2003 and 2006, we used an extraarticular, cannulated, fully threaded posterior calcaneotibial screw to prevent equinus contracture in 10 patients (four male and six female patients, 14 limbs) undergoing tibial lengthening with the intramedullary skeletal kinetic distractor. Diagnoses were fibular hemimelia (two), mesomelic dwarfism (two), posteromedial bow (one), hemihypertrophy (one), poliomyelitis (one), achondroplasia (one), posttraumatic limb-length discrepancy (one), and hypochondroplasia (one). Average age was 24.5 years (range, 15–54 years). The screw (length, typically 125 mm; diameter, 7 mm) was inserted with the ankle in 10° dorsiflexion. Gastrocnemius soleus recession was performed in two patients to achieve 10° dorsiflexion. Average lengthening was 4.9 cm (range, 3–7 cm). Screws were removed after a mean 3.3 months (range, 2–6 months). Preoperative ankle range of motion was regained within 6 months of screw removal. No neurovascular complications were encountered, and no patients experienced equinus contracture. We also conducted a cadaveric study in which one surgeon inserted screws in eight cadaveric legs under image intensifier control. The flexor hallucis longus muscle belly was the closest anatomic structure noted during dissection. The screw should be inserted obliquely from upper lateral edge of the calcaneus and aimed lateral in the tibia to avoid the flexor hallucis longus muscle. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18800215

The relationship between Shin Splints with anthropometric characteristics and some indicators of body composition.

PubMed

Sabeti, V; Khoshraftar Yazdi, N; Bizheh, N

2014-10-06

Medial tibial stress syndrome (MTSS), commonly known as ''shin splints,'' is a frequent injury of the lower extremity and one of the most common causes of exertional leg pain in athletes. The aim of this study was to study the relationship between Shin splints, anthropometric characteristics and some indicators of body composition. In this descriptive - comparative study, thirty--five students of physical education were evaluated in two groups: Shin Splints group [(n=17) , mean (± SD) height and weight, 161.52 ± 5.32 and 56.85 ± 9.30 respectively] and healthy group [(n=18) ,mean (± SD) height and weight, 162.75 ± 3.85 and 54.73 ± 6.36 respectively]. Anthropometric and body composition characteristic of both groups were studied under identical conditions. Independent t--test was performed in order to analyze the data. No significant differences were found in anthropometric parameters (thigh length, leg length, foot length and leg circumference) body composition (the amount of minerals and body fat percentage) between the healthy group and the Shin Splints group (P> 0/05). According to the results of this study, anthropometric characteristics and body composition indicators may not be regarded as a risk factor for shin splints.

Talent identification model for sprinter using discriminant factor

NASA Astrophysics Data System (ADS)

Kusnanik, N. W.; Hariyanto, A.; Herdyanto, Y.; Satia, A.

2018-01-01

The main purpose of this study was to identify young talented sprinter using discriminant factor. The research was conducted in 3 steps including item pool, screening of item pool, and trial of instruments at the small and big size of samples. 315 male elementary school students participated in this study with mean age of 11-13 years old. Data were collected by measuring anthropometry (standing height, sitting height, body mass, and leg length); testing physical fitness (40m sprint for speed, shuttle run for agility, standing broad jump for power, multistage fitness test for endurance). Data were analyzed using discriminant factor. The result of this study found that there were 5 items that selected as an instrument to identify young talented sprinter: sitting height, body mass, leg length, sprint 40m, and multistage fitness test. Model of Discriminant for talent identification in sprinter was D = -24,497 + (0,155 sitting height) + (0,080 body mass) + (0,148 leg length) + (-1,225 Sprint 40m) + (0,563 MFT). The conclusion of this study: instrument tests that have been selected and discriminant model that have been found can be applied to identify young talented as a sprinter.

Development of PIMAL: Mathematical Phantom with Moving Arms and Legs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akkurt, Hatice; Eckerman, Keith F.

2007-05-01

The computational model of the human anatomy (phantom) has gone through many revisions since its initial development in the 1970s. The computational phantom model currently used by the Nuclear Regulatory Commission (NRC) is based on a model published in 1974. Hence, the phantom model used by the NRC staff was missing some organs (e.g., neck, esophagus) and tissues. Further, locations of some organs were inappropriate (e.g., thyroid).Moreover, all the computational phantoms were assumed to be in the vertical-upright position. However, many occupational radiation exposures occur with the worker in other positions. In the first phase of this work, updates onmore » the computational phantom models were reviewed and a revised phantom model, which includes the updates for the relevant organs and compositions, was identified. This revised model was adopted as the starting point for this development work, and hence a series of radiation transport computations, using the Monte Carlo code MCNP5, was performed. The computational results were compared against values reported by the International Commission on Radiation Protection (ICRP) in Publication 74. For some of the organs (e.g., thyroid), there were discrepancies between the computed values and the results reported in ICRP-74. The reasons behind these discrepancies have been investigated and are discussed in this report.Additionally, sensitivity computations were performed to determine the sensitivity of the organ doses for certain parameters, including composition and cross sections used in the simulations. To assess the dose for more realistic exposure configurations, the phantom model was revised to enable flexible positioning of the arms and legs. Furthermore, to reduce the user time for analyses, a graphical user interface (GUI) was developed. The GUI can be used to visualize the positioning of the arms and legs as desired posture is achieved to generate the input file, invoke the computations, and extract the organ dose values from the MCNP5 output file. In this report, the main features of the phantom model with moving arms and legs and user interface are described.« less

Biomechanical characteristics and speed adaptation during kick double poling on roller skis in elite cross-country skiers.

PubMed

Göpfert, Caroline; Holmberg, Hans-Christer; Stöggl, Thomas; Müller, Erich; Lindinger, Stefan Josef

2013-06-01

Recent developments in cross-country ski racing should promote the use of kick double poling. This technique, however, has not been the focus in athletes' training and has barely been investigated. The aims of the present study were to develop a function-based phase definition and to analyse speed adaptation mechanisms for kick double poling in elite cross-country skiers. Joint kinematics and pole/plantar forces were recorded in 10 athletes while performing kick double poling at three submaximal roller skiing speeds. A speed increase was associated with increases in cycle length and rate, while absolute poling and leg push-off durations shortened. Despite maintained impulses of force, the peak and average pole/leg forces increased. During double poling and leg push-off, ranges of motion of elbow flexion and extension increased (p < 0.05) and were maintained for hip/knee flexion and extension. Cycle length increase was correlated to increases in average poling force (r = 0.71) and arm swing time (r = 0.88; both p < 0.05). The main speed adaptation was achieved by changes in double poling technique; however, leg push-off showed high variability among elite skiers, thus illustrating important aspects for technique training.

An approach to scoring cursorial limb proportions in carnivorous dinosaurs and an attempt to account for allometry.

PubMed

Persons, W Scott; Currie, Philip J

2016-01-27

From an initial dataset of 53 theropod species, the general relationship between theropod lower-leg length and body mass is identified. After factoring out this allometric relationship, theropod hindlimb proportions are assessed irrespective of body mass. Cursorial-limb-proportion (CLP) scores derived for each of the considered theropod taxa offer a measure of the extent to which a particular species deviates in favour of higher or lower running speeds. Within the same theropod species, these CLP scores are found to be consistent across multiple adult specimens and across disparate ontogenetic stages. Early theropods are found to have low CLP scores, while the coelurosaurian tyrannosauroids and compsognathids are found to have high CLP scores. Among deinonychosaurs, troodontids have consistently high CLP scores, while many dromaeosaur taxa, including Velociraptor and Deinonychus, have low CLP scores. This indicates that dromaeosaurs were not, overall, a particularly cursorily adapted group. Comparisons between the CLP scores of Tyrannosaurus and specimens referred to the controversial genus Nanotyrannus indicate a strong discrepancy in cursorial adaptations, which supports the legitimacy of Nanotyrannus and the previous suggestions of ecological partitioning between Nanotyrannus and the contemporaneous Tyrannosaurus.

Outcome after cementless total hip arthroplasty for arthritic hip in patients with residual poliomyelitis: a case series.

PubMed

Cho, Yoon J; Lee, Choong H; Chun, Young S; Rhyu, Kee H

2016-09-29

In this case series, we investigated the outcome of cementless total hip arthroplasty (THA) for advanced hip osteoarthritis in patients with residual poliomyelitis to evaluate its clinical usefulness for these patients. 11 unilateral cementless primary THA were performed to arthritic hips in patients with residual poliomyelitis. 7 were in paralytic and 4 were in nonparalytic limbs. The mean follow-up duration was 79.9 months. Retrospective clinical evaluations with various scores and radiological evaluations were made. Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Short-form (SF)-36 physical scales were significantly improved after the surgery. However, UCLA activity score and SF-36 mental scale were not. Because of remaining leg length discrepancies, all but 1 noted a residual limp. In nonparalytic hip, functional acetabular cup inclination during weight bearing significantly increased from installed inclination. Other than 1 case of posterior dislocation, no complications were observed. Although the overall result itself is excellent, THA for these patients cannot improve limp, physical activity and mental status. Surgeons should be aware of the change of the inclination of acetabular cup during mobilisation, especially for THA in contralateral hip.

[The monorail system--bone segment transport over unreamed interlocking nails].

PubMed

Oedekoven, G; Jansen, D; Raschke, M; Claudi, B F

1996-11-01

A treatment protocol is demonstrated, consisting of an osteotomy, either proximal or distal, of the bone defect with subsequent segmental transport via an anteromedially (tibia) or laterally (femur) mounted AO external fixation over an unreamed interlocking nail (monorail system). Twenty patients were treated by this method with indications as follows: 13 had a segmental bone defect of the tibia, 3 of the femur. Three patients showed post-traumatic and postinfectious leg-length discrepancies and one was treated for hypertrophic non-union of the femur. Defect distance varied between 5 and 18.5 cm and average time for transport was 19,42 days/ cm for the tibial shaft, 15,93 days/cm for the femur. Two patients developed deep infection, which required change of treatment, removing the monorail system and application of an Ilizarov apparatus. Despite complications using the monorail system, all patients healed and no amputations were required. The monorail system can be used as an alternative to the Ilizarov method under certain criteria of patient selection; these criteria are shown by an algorithm for segmental bone defects without infection, respecting the soft-tissue status with or without neurovascular compromise.

An approach to scoring cursorial limb proportions in carnivorous dinosaurs and an attempt to account for allometry

PubMed Central

Persons IV, W. Scott; Currie, Philip J.

2016-01-01

From an initial dataset of 53 theropod species, the general relationship between theropod lower-leg length and body mass is identified. After factoring out this allometric relationship, theropod hindlimb proportions are assessed irrespective of body mass. Cursorial-limb-proportion (CLP) scores derived for each of the considered theropod taxa offer a measure of the extent to which a particular species deviates in favour of higher or lower running speeds. Within the same theropod species, these CLP scores are found to be consistent across multiple adult specimens and across disparate ontogenetic stages. Early theropods are found to have low CLP scores, while the coelurosaurian tyrannosauroids and compsognathids are found to have high CLP scores. Among deinonychosaurs, troodontids have consistently high CLP scores, while many dromaeosaur taxa, including Velociraptor and Deinonychus, have low CLP scores. This indicates that dromaeosaurs were not, overall, a particularly cursorily adapted group. Comparisons between the CLP scores of Tyrannosaurus and specimens referred to the controversial genus Nanotyrannus indicate a strong discrepancy in cursorial adaptations, which supports the legitimacy of Nanotyrannus and the previous suggestions of ecological partitioning between Nanotyrannus and the contemporaneous Tyrannosaurus. PMID:26813782

The short legs of great apes: evidence for aggressive behavior in australopiths.

PubMed

Carrier, David R

2007-03-01

Early hominins, australopiths, were similar to most large primates in having relatively short hindlimbs for their body size. The short legs of large primates are thought to represent specialization for vertical climbing and quadrupedal stability on branches. Although this may be true, there are reasons to suspect that the evolution of short legs may also represent specialization for physical aggression. Fighting in apes is a behavior in which short legs are expected to improve performance by lowering the center of mass during bipedal stance and by increasing the leverage through which muscle forces can be applied to the ground. Among anthropoid primates, body size sexual dimorphism (SSD) and canine height sexual dimorphism (CSD) are strongly correlated with levels of male-male competition, allowing SSD and CSD to be used as indices of male-male aggression. Here I show that the evolution of hindlimb length in apes is inversely correlated with the evolution of SSD (R(2)= 0.683, P-value = 0.006) and the evolution of CSD (R(2)= 0.630, P-value = 0.013). In contrast, a significant correlation was not observed for the relationship between the evolution of hindlimb and forelimb lengths. These observations are consistent with the suggestion that selection for fighting performance has maintained relatively short hindlimbs in species of Hominoidea with high levels of male-male competition. Although australopiths were highly derived for striding bipedalism when traveling on the ground, they retained short legs compared to those of Homo for over two million years, approximately 100,000 generations. Their short legs may be indicative of persistent selection for high levels of aggression.

Milnesium minutum and Milnesium sandrae, two new species of Milnesiidae (Tardigrada, Eutardigrada, Apochela).

PubMed

Pilato, Giovanni; Lisi, Oscar

2016-01-01

Two new species of Milnesium are described, Milnesium minutum sp. n. from Sicily and Milnesium sandrae sp. n. from the Hawaiian Archipelago. The body size of Milnesium minutum is the smallest of the known species of the genus. The stylet supports are inserted on the buccal tube at 63-66% of its length and the claws have a [3-3]-[3-3] configuration. Milnesium sandrae has stylet supports inserted on the buccal tube at 58-60.5% of its length, a [3-3]-[3-3] claw configuration, and the percent ratio between the secondary claw and primary claw length on legs I-III (78.6%-85.5%) clearly higher than on legs IV (70.5%-71.4%). With the description of these two new species, the number of species in the genus is increased to 31.

The effects of klapskate hinge position on push-off performance: a simulation study.

PubMed

Houdijk, Han; Bobbert, Maarten F; De Koning, Jos J; De Groot, Gert

2003-12-01

The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this model performed a one-leg vertical jump, from a frictionless surface, while keeping its trunk horizontally. In this model, klapskate hinge position was varied by varying the length of the foot segment between 115 and 300 mm. With each foot length, an optimal control solution was found that resulted in the maximal amount of vertical kinetic and potential energy of the body's center of mass at take off (Weff). Foot length was shown to considerably affect push-off performance. Maximal Weff was obtained with a foot length of 185 mm and decreased by approximately 25% at either foot length of 115 mm and 300 mm. The reason for this decrease was that foot length affected the onset and control of foot rotation. This resulted in a distortion of the pattern of leg segment rotations and affected muscle work (Wmus) and the efficacy ratio (Weff/Wmus) of the entire leg system. Despite its simplicity, the model very well described and explained the effects of klapskate hinge position on push off performance that have been observed in speed-skating experiments. The simplicity of the model, however, does not allow quantitative analyses of optimal klapskate hinge position for speed-skating practice.

The use of tibial tuberosity-trochlear groove indices based on joint size in lower limb evaluation.

PubMed

Ferlic, Peter Wilhelm; Runer, Armin; Dirisamer, Florian; Balcarek, Peter; Giesinger, Johannes; Biedermann, Rainer; Liebensteiner, Michael Christian

2018-05-01

The correlation between tibial tuberosity-trochlear groove distance (TT-TG) and joint size, taking into account several different parameters of knee joint size as well as lower limb dimensions, is evaluated in order to assess whether TT-TG indices should be used in instead of absolute TT-TG values. This study comprised a retrospective analysis of knee CT scans, including 36 cases with patellofemoral instability (PFI) and 30 controls. Besides TT-TG, five measures of knee joint size were evaluated in axial CT slices: medio-lateral femur width, antero-posterior lateral condylar height, medio-lateral width of the tibia, width of the patella and the proximal-distal joint size (TT-TE). Furthermore, the length of the femur, the tibia and the total leg length were measured in the CT scanogram. Correlation analysis of TT-TG and the other parameters was done by calculating the Spearman correlation coefficient. In the PFI group lateral condylar height (r = 0.370), tibia width (r = 0.406) and patella width (r = 0.366) showed significant moderate correlations (p < 0.03) with TT-TG. Furthermore, we found a significant correlation between TT-TG and tibia length (r = 0.371) and total leg length (r = 381). The control group showed no significant correlation between TT-TG and knee joint size or between TT-TG and measures of lower limb length. Tibial tuberosity-trochlear groove distance correlates with several parameters of knee joint size and leg length in patients with patellofemoral instability. Application of indices determining TT-TG as a ratio of joint size could be helpful in establishing the indication for medial transfer of the tibial tuberosity in patients with PFI. Level III.

Segment-specific resistivity improves body fluid volume estimates from bioimpedance spectroscopy in hemodialysis patients.

PubMed

Zhu, F; Kuhlmann, M K; Kaysen, G A; Sarkar, S; Kaitwatcharachai, C; Khilnani, R; Stevens, L; Leonard, E F; Wang, J; Heymsfield, S; Levin, N W

2006-02-01

Discrepancies in body fluid estimates between segmental bioimpedance spectroscopy (SBIS) and gold-standard methods may be due to the use of a uniform value of tissue resistivity to compute extracellular fluid volume (ECV) and intracellular fluid volume (ICV). Discrepancies may also arise from the exclusion of fluid volumes of hands, feet, neck, and head from measurements due to electrode positions. The aim of this study was to define the specific resistivity of various body segments and to use those values for computation of ECV and ICV along with a correction for unmeasured fluid volumes. Twenty-nine maintenance hemodialysis patients (16 men) underwent body composition analysis including whole body MRI, whole body potassium (40K) content, deuterium, and sodium bromide dilution, and segmental and wrist-to-ankle bioimpedance spectroscopy, all performed on the same day before a hemodialysis. Segment-specific resistivity was determined from segmental fat-free mass (FFM; by MRI), hydration status of FFM (by deuterium and sodium bromide), tissue resistance (by SBIS), and segment length. Segmental FFM was higher and extracellular hydration of FFM was lower in men compared with women. Segment-specific resistivity values for arm, trunk, and leg all differed from the uniform resistivity used in traditional SBIS algorithms. Estimates for whole body ECV, ICV, and total body water from SBIS using segmental instead of uniform resistivity values and after adjustment for unmeasured fluid volumes of the body did not differ significantly from gold-standard measures. The uniform tissue resistivity values used in traditional SBIS algorithms result in underestimation of ECV, ICV, and total body water. Use of segmental resistivity values combined with adjustment for body volumes that are neglected by traditional SBIS technique significantly improves estimations of body fluid volume in hemodialysis patients.

EFFECT OF HEEL LIFTS ON PATELLOFEMORAL JOINT STRESS DURING RUNNING.

PubMed

Mestelle, Zachary; Kernozek, Thomas; Adkins, Kelly S; Miller, Jessica; Gheidi, Naghmeh

2017-10-01

Patellofemoral pain is a debilitating injury for many recreational runners. Excessive patellofemoral joint stress may be the underlying source of pain and interventions often focus on ways to reduce patellofemoral joint stress. Heel lifts have been used as an intervention within Achilles tendon rehabilitation programs and to address leg length discrepancies. The purpose of this study was to examine the effect of running with heel lifts on patellofemoral joint stress, patellofemoral stress impulse, quadriceps force, step length, cadence, and other related kinematic and spatiotemporal variables. A repeated-measures research design. Sixteen healthy female runners completed five running trials in a controlled laboratory setting with and without 11mm heel lifts inserted in a standard running shoe. Kinetic and kinematic data were used in combination with a static optimization technique to estimate individual muscle forces. These data were inserted into a patellofemoral joint model which was used to estimate patellofemoral joint stress and other variables during running. When running with heel lifts, peak patellofemoral joint stress and patellofemoral stress impulse were reduced by a 4.2% (p=0.049) and 9.3% (p=0.002). Initial center of pressure was shifted anteriorly 9.1% when running with heel lifts (p<0.001) despite all runners utilizing a heel strike pattern. Dorsiflexion at initial contact was reduced 28% (p=0.016) when heel lifts were donned. No differences in step length and cadence (p>0.05) were shown between conditions. Heel lift use resulted in decreased patellofemoral joint stress and impulse without associated changes in step length or frequency, or other variables shown to influence patellofemoral joint stress. The center of pressure at initial contact was also more anterior using heel lifts. The use of heel lifts may have therapeutic benefits for runners with patellofemoral pain if the primary goal is to reduce patellofemoral joint stress. 3b.

EFFECT OF HEEL LIFTS ON PATELLOFEMORAL JOINT STRESS DURING RUNNING

PubMed Central

Mestelle, Zachary; Kernozek, Thomas; Adkins, Kelly S.; Miller, Jessica; Gheidi, Naghmeh

2017-01-01

Background Patellofemoral pain is a debilitating injury for many recreational runners. Excessive patellofemoral joint stress may be the underlying source of pain and interventions often focus on ways to reduce patellofemoral joint stress. Purpose Heel lifts have been used as an intervention within Achilles tendon rehabilitation programs and to address leg length discrepancies. The purpose of this study was to examine the effect of running with heel lifts on patellofemoral joint stress, patellofemoral stress impulse, quadriceps force, step length, cadence, and other related kinematic and spatiotemporal variables. Study Design A repeated-measures research design Methods Sixteen healthy female runners completed five running trials in a controlled laboratory setting with and without 11mm heel lifts inserted in a standard running shoe. Kinetic and kinematic data were used in combination with a static optimization technique to estimate individual muscle forces. These data were inserted into a patellofemoral joint model which was used to estimate patellofemoral joint stress and other variables during running. Results When running with heel lifts, peak patellofemoral joint stress and patellofemoral stress impulse were reduced by a 4.2% (p=0.049) and 9.3% (p=0.002). Initial center of pressure was shifted anteriorly 9.1% when running with heel lifts (p<0.001) despite all runners utilizing a heel strike pattern. Dorsiflexion at initial contact was reduced 28% (p=0.016) when heel lifts were donned. No differences in step length and cadence (p>0.05) were shown between conditions. Conclusions Heel lift use resulted in decreased patellofemoral joint stress and impulse without associated changes in step length or frequency, or other variables shown to influence patellofemoral joint stress. The center of pressure at initial contact was also more anterior using heel lifts. The use of heel lifts may have therapeutic benefits for runners with patellofemoral pain if the primary goal is to reduce patellofemoral joint stress. Level of Evidence 3b PMID:29181248

Estimation of stature by using lower limb dimensions in the Malaysian population.

PubMed

Nor, Faridah Mohd; Abdullah, Nurliza; Mustapa, Al-Mizan; Qi Wen, Leong; Faisal, Nurulina Aimi; Ahmad Nazari, Dayang Anis Asyikin

2013-11-01

Estimation of stature is an important step in developing a biological profile for human identification. It may provide a valuable indicator for an unknown individual in a population. The aim of this study was to analyse the relationship between stature and lower limb dimensions in the Malaysian population. The sample comprised 100 corpses, which included 69 males and 31 females between the age range of 20-90 years old. The parameters measured were stature, thigh length, lower leg length, leg length, foot length, foot height and foot breadth. Results showed that the mean values in males were significantly higher than those in females (p < 0.05). There were significant correlations between lower limb dimensions and stature. Cross-validation of the equation on 100 individuals showed close approximation between known stature and estimated stature. It was concluded that lower limb dimensions were useful for estimation of stature, which should be validated in future studies. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Three-dimensional topographies of water surface dimples formed by superhydrophobic water strider legs

NASA Astrophysics Data System (ADS)

Yin, W.; Zheng, Y. L.; Lu, H. Y.; Zhang, X. J.; Tian, Y.

2016-10-01

A water strider has a remarkable capability to stand and walk freely on water. Supporting forces of a water strider and a bionic robot have been calculated from the side view of pressed depth of legs to reconstruct the water surface dimples. However, in situ measurements of the multiple leg forces and significantly small leg/water contact dimples have not been realized yet. In this study, a shadow method was proposed to reconstruct the in situ three-dimensional topographies of leg/water contact dimples and their corresponding supporting forces. Results indicated that the supporting forces were affected by the depth, width, and length of the dimple, and that the maximum dimple depth was not proportional to the supporting forces. The shadow method also has advantages in disclosing tiny supporting force of legs in their subtle actions. These results are helpful for understanding the locomotion principles of water-walking insects and the design of biomimetic aquatic devices.

The influence of pelvic adjustment on vertical jump height in female university students with functional leg length inequality.

PubMed

Gong, Wontae

2015-01-01

[Purpose] This study aimed to investigate the effect of pelvic adjustment on vertical jump height (VJH) in female university students with functional leg length inequality (FLLI). [Subjects] Thirty female university students with FLLI were divided into a pelvic adjustment group (n = 15) and a stretching (control) group (n = 15). [Methods] VJH was measured using an OptoGait. [Results] After the intervention, jump height improved significantly compared with the pre-intervention height only in the pelvic adjustment group, while FLLI showed statistically significant improvement in both groups. [Conclusion] Pelvic adjustment as per the Gonstead method can be applied as a method of reducing FLLI and increasing VJH.

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

PubMed Central

Jayaram, Kaushik; Full, Robert J.

2016-01-01

Jointed exoskeletons permit rapid appendage-driven locomotion but retain the soft-bodied, shape-changing ability to explore confined environments. We challenged cockroaches with horizontal crevices smaller than a quarter of their standing body height. Cockroaches rapidly traversed crevices in 300–800 ms by compressing their body 40–60%. High-speed videography revealed crevice negotiation to be a complex, discontinuous maneuver. After traversing horizontal crevices to enter a vertically confined space, cockroaches crawled at velocities approaching 60 cm⋅s−1, despite body compression and postural changes. Running velocity, stride length, and stride period only decreased at the smallest crevice height (4 mm), whereas slipping and the probability of zigzag paths increased. To explain confined-space running performance limits, we altered ceiling and ground friction. Increased ceiling friction decreased velocity by decreasing stride length and increasing slipping. Increased ground friction resulted in velocity and stride length attaining a maximum at intermediate friction levels. These data support a model of an unexplored mode of locomotion—“body-friction legged crawling” with body drag, friction-dominated leg thrust, but no media flow as in air, water, or sand. To define the limits of body compression in confined spaces, we conducted dynamic compressive cycle tests on living animals. Exoskeletal strength allowed cockroaches to withstand forces 300 times body weight when traversing the smallest crevices and up to nearly 900 times body weight without injury. Cockroach exoskeletons provided biological inspiration for the manufacture of an origami-style, soft, legged robot that can locomote rapidly in both open and confined spaces. PMID:26858443

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot.

PubMed

Jayaram, Kaushik; Full, Robert J

2016-02-23

Jointed exoskeletons permit rapid appendage-driven locomotion but retain the soft-bodied, shape-changing ability to explore confined environments. We challenged cockroaches with horizontal crevices smaller than a quarter of their standing body height. Cockroaches rapidly traversed crevices in 300-800 ms by compressing their body 40-60%. High-speed videography revealed crevice negotiation to be a complex, discontinuous maneuver. After traversing horizontal crevices to enter a vertically confined space, cockroaches crawled at velocities approaching 60 cm⋅s(-1), despite body compression and postural changes. Running velocity, stride length, and stride period only decreased at the smallest crevice height (4 mm), whereas slipping and the probability of zigzag paths increased. To explain confined-space running performance limits, we altered ceiling and ground friction. Increased ceiling friction decreased velocity by decreasing stride length and increasing slipping. Increased ground friction resulted in velocity and stride length attaining a maximum at intermediate friction levels. These data support a model of an unexplored mode of locomotion--"body-friction legged crawling" with body drag, friction-dominated leg thrust, but no media flow as in air, water, or sand. To define the limits of body compression in confined spaces, we conducted dynamic compressive cycle tests on living animals. Exoskeletal strength allowed cockroaches to withstand forces 300 times body weight when traversing the smallest crevices and up to nearly 900 times body weight without injury. Cockroach exoskeletons provided biological inspiration for the manufacture of an origami-style, soft, legged robot that can locomote rapidly in both open and confined spaces.

Milnesium minutum and Milnesium sandrae, two new species of Milnesiidae (Tardigrada, Eutardigrada, Apochela)

PubMed Central

Pilato, Giovanni; Lisi, Oscar

2016-01-01

Abstract Two new species of Milnesium are described, Milnesium minutum sp. n. from Sicily and Milnesium sandrae sp. n. from the Hawaiian Archipelago. The body size of Milnesium minutum is the smallest of the known species of the genus. The stylet supports are inserted on the buccal tube at 63–66% of its length and the claws have a [3-3]-[3-3] configuration. Milnesium sandrae has stylet supports inserted on the buccal tube at 58–60.5% of its length, a [3-3]-[3-3] claw configuration, and the percent ratio between the secondary claw and primary claw length on legs I–III (78.6%–85.5%) clearly higher than on legs IV (70.5%–71.4%). With the description of these two new species, the number of species in the genus is increased to 31. PMID:27110205

Divertor-localized fluctuations in NSTX-U L-mode discharges

NASA Astrophysics Data System (ADS)

Scotti, Filippo; Soukhanovskii, V. A.; Zweben, S.; Myra, J.; Baver, D.; Sabbagh, S. A.

2017-10-01

The 3-D structure of divertor turbulence is characterized in NSTX-U by means of fast camera imaging. Edge and divertor turbulence can be important in determining the heat flux width in fusion devices. Field-aligned filaments are found on the divertor legs via imaging of C III and D- α emission in NBI-heated diverted L-mode discharges, similar to observations in Alcator C-Mod and MAST. These flute-like fluctuations of up to 10-20% in RMS/mean are radially localized around the separatrix and limited to the region below the X-point. Poloidal and parallel correlation lengths are a few cm (10-50ρi) and several meters, respectively. For the outer leg filaments, poloidal correlation lengths decrease along the leg away from the strike point and typical effective toroidal mode numbers are in the range of 10-20. Opposite toroidal rotation is observed for inner (co-current rotation) and outer leg (counter-current rotation) filaments with apparent poloidal propagation of 1 km/s. The poloidal motion of outer leg filaments is opposite to the one typically observed for NSTX upstream blobs in the scrape-off layer. The shape, dynamics and absence of correlation with upstream turbulence suggest that these fluctuations are generated and localized in the divertor region. Supported by US DOE DE-AC52-07NA27344, DE-AC02-09CH11466, DE-FG02- 02ER54678, DE-FG02-99ER54524.

Lower Extremity Limb Salvage with Cross Leg Pedicle Flap, Cross Leg Free Flap, and Cross Leg Vascular Cable Bridge Flap.

PubMed

Manrique, Oscar J; Bishop, Sarah N; Ciudad, Pedro; Adabi, Kian; Martinez-Jorge, Jorys; Moran, Steven L; Huang, Tony; Vijayasekaran, Aparna; Chen, Shih-Heng; Chen, Hung-Chi

2018-05-16

 Lower extremity salvage following significant soft tissue loss can be complicated by lack of recipient vessel for free tissue transfer. We describe our experience in lower limb salvage for patients with no recipient vessels with the use of pedicle, free and cable bridge flaps.  A retrospective review from 1985 to 2017 of patients undergoing lower limb salvage using a contralateral pedicle cross leg (PCL) flaps, free cross leg (FCL) flaps, or free cable bridge (FCB) flaps was conducted. Demographics, etiology of the reconstruction, type of flap used, donor-site vessels, defect size, operating time, time of pedicle division, length of hospital stay, time to ambulation, and complications were analyzed.  A total of 53 patients (48 males and 5 females) with an average age of 35 years (range, 29-38 years) were identified. The etiology for the reconstruction was trauma in 52 patients and oncological resection in 1 patient. There were 18 PCL, 25 FCL, and 10 FCB completed. The recipient vessels for all flaps were the posterior tibial artery and vein. The average operating room times for PCL, FCL, and FCB flaps were 4, 9, and 10 hours, respectively. The average length of hospital stay was 5 weeks and average time to ambulation was 4 weeks. The average follow-up time was 7.5 years (range, 3-12 years). Complications encountered were hematoma (six), prolonged pain (six), total flap loss (two), reoperation (five), and infection (four). Limb salvage rates were 96.2%.  When ipsilateral limb vessels are not available, and other reconstructive options have been exhausted, cross leg flaps can be a viable option for limb salvage in the setting of extensive defects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Influence of running velocity on vertical, leg and joint stiffness : modelling and recommendations for future research.

PubMed

Brughelli, Matt; Cronin, John

2008-01-01

Human running can be modelled as either a spring-mass model or multiple springs in series. A force is required to stretch or compress the spring, and thus stiffness, the variable of interest in this paper, can be calculated from the ratio of this force to the change in spring length. Given the link between force and length change, muscle stiffness and mechanical stiffness have been areas of interest to researchers, clinicians, and strength and conditioning practitioners for many years. This review focuses on mechanical stiffness, and in particular, vertical, leg and joint stiffness, since these are the only stiffness types that have been directly calculated during human running. It has been established that as running velocity increases from slow-to-moderate values, leg stiffness remains constant while both vertical stiffness and joint stiffness increase. However, no studies have calculated vertical, leg or joint stiffness over a range of slow-to-moderate values to maximum values in an athletic population. Therefore, the effects of faster running velocities on stiffness are relatively unexplored. Furthermore, no experimental research has examined the effects of training on vertical, leg or joint stiffness and the subsequent effects on running performance. Various methods of training (Olympic style weightlifting, heavy resistance training, plyometrics, eccentric strength training) have shown to be effective at improving running performance. However, the effects of these training methods on vertical, leg and joint stiffness are unknown. As a result, the true importance of stiffness to running performance remains unexplored, and the best practice for changing stiffness to optimize running performance is speculative at best. It is our hope that a better understanding of stiffness, and the influence of running speed on stiffness, will lead to greater interest and an increase in experimental research in this area.

CT scanography for limb length determination.

PubMed

O'Connor, K J; Grady, J F; Hollander, M

1988-04-01

The authors present an alternative to classic techniques used to measure limb length discrepancy radiographically. CT scanography seems to have advantages over currently-used Bell-Thompson roentgenography in that it uses less radiation and is of no increase in cost.

War, forced displacement and growth in Laotian adults.

PubMed

Clarkin, Patrick F

2012-01-01

Evidence from several populations suggests that war negatively impacts civilian nutrition, physical growth and overall health. This effect is often enduring or permanent, particularly if experienced early in life. To assess whether the number of lifetime displacement experiences and being displaced in infancy were associated with adult height, sitting height, leg length and the sitting height ratio. Retrospective questionnaires on displacement and resettlement experiences and anthropometric data were collected from a sample of Laotian adult refugees (ethnic Hmong and Lao; n = 365). All were born in Laos or Thailand and had resettled in French Guiana or the US. Many had been displaced several times by military conflict in Laos. In bivariate analyses, being displaced in infancy and the number of lifetime displacement experiences one had were negatively associated with final adult height and leg length in both sexes. The association was stronger in females, particularly Hmong females. There was no significant association between total displacement experiences and the sitting height ratio. In multiple regression analyses, linear growth in males was negatively associated with being displaced in infancy; in females, the number of lifetime displacement experiences was a significant predictor. Forced displacement from war appears to have a lasting effect on final adult height, sitting height and leg length, although not necessarily on the sitting height ratio in this sample.

Estimating physical activity in children: impact of pedometer wear time and metric.

PubMed

Laurson, Kelly R; Welk, Gregory J; Eisenmann, Joey C

2015-01-01

The purpose of this study was to provide a practical demonstration of the impact of monitoring frame and metric when assessing pedometer-determined physical activity (PA) in youth. Children (N = 1111) were asked to wear pedometers over a 7-day period during which time worn and steps were recorded each day. Varying data-exclusion criteria were used to demonstrate changes in estimates of PA. Steps were expressed using several metrics and criteria, and construct validity was demonstrated via correlations with adiposity. Meaningful fluctuations in average steps per day and percentage meeting PA recommendations were apparent when different criteria were used. Children who wore the pedometer longer appeared more active, with each minute the pedometer was worn each day accounting for an approximate increase of 11 and 8 steps for boys and girls, respectively (P < .05). Using more restrictive exclusion criteria led to stronger correlations between indices of steps per day, steps per minute, steps per leg length, steps per minute per leg length, and obesity. Wear time has a meaningful impact on estimates of PA. This should be considered when determining exclusion criteria and making comparisons between studies. Results also suggest that incorporating wear time per day and leg length into the metric may increase validity of PA estimates.

Effects of Wheelchair Seat-height Settings on Alternating Lower Limb Propulsion With Both Legs.

PubMed

Murata, Tomoyuki; Asami, Toyoko; Matsuo, Kiyomi; Kubo, Atsuko; Okigawa, Etsumi

2014-01-01

This study investigated the effects of seat-height settings of wheelchairs with alternating propulsion with both legs. Seven healthy individuals with no orthopedic disease participated. Flexion angles at initial contact (FA-IC) of each joint, range of motion during propulsion period (ROM-PP), and ground reaction force (GRF) were measured using a three dimensional motion capture system and force plates, and compared with different seat-height settings. Statistically significant relationships were found between seat-height and speed, stride length, knee FA-IC, ankle FA-IC, hip ROM-PP, vertical ground reaction force (VGRF), and anterior posterior ground reaction force (APGRF). Speed, hip ROM-PP, VGRF and APGRF increased as the seat-height was lowered. This effect diminished when the seat-height was set below -40 mm. VGRF increased as the seat-height was lowered. The results suggest that the seat-height effect can be attributed to hip ROM-PP; therefore, optimal foot propulsion cannot be achieved when the seat height is set either too high or too low. Efficient foot propulsion of the wheelchair can be achieved by setting the seat height to lower leg length according to a combination of physical characteristics, such as the user's physical functions, leg muscles, and range of motion.

Thermoelectric Oxide Modules (TOMs) for the Direct Conversion of Simulated Solar Radiation into Electrical Energy

PubMed Central

Tomeš, Petr; Trottmann, Matthias; Suter, Clemens; Aguirre, Myriam Heidi; Steinfeld, Aldo; Haueter, Philipp; Weidenkaff, Anke

2010-01-01

The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM). These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La1.98Sr0.02CuO4) and two n-type (CaMn0.98Nb0.02O3) thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS) which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al2O3 substrate compared to the uncoated surface on ΔT, Pmax and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm-2 and the dependence of η on the leg length was investigated.

A new species of Pseudomacrochiron Reddiah, 1969 (Crustacea: Copepoda: Macrochironidae) associated with scyphistomae of the moon jellyfish Aurelia sp. (Cnidaria: Scyphozoa) off Japan.

PubMed

Tang, Danny; Yasuda, Akira; Yamada, Satoshi; Nagasawa, Kazuya

2012-02-01

A new species of the Macrochironidae Humes & Boxshall, 1996 (Copepoda: Cyclopoida), Pseudomacrochiron aureliae n. sp., is described based on adult specimens extracted from the gastrovacular cavity of the scyphistomae of Aurelia sp. (Cnidaria: Scyphozoa) collected in the Seto Inland Sea and Ise Bay off the coast of Japan. The new species differs from its congeners by having the following combination of characters: a caudal ramus with a length to width ratio of 3.1; an accessory flagellum on caudal setae II, III and VI; three apical setae on the maxillule; only setae I and II on the maxillary basis; two short spines on the female maxilliped claw (endopod); an armature of III, I, 4 on the terminal exopodal segment of leg 3; an armature of I, II, 2 on the terminal endopodal segment of leg 3; an armature of II, I, 4 on the terminal exopodal segment of leg 4; and a short free exopodal segment of leg 5 (length to width ratio of 1.4) armed with a long seta and short spine. P. aureliae n. sp. is the first member of the genus reported from off Japan and from the scyphistomae of its scyphozoan host.

Stimulated Brillouin Scattering Phase Conjugation in Fiber Optic Waveguides

DTIC Science & Technology

2008-07-01

61] The discrepancy is reduced since the effective length of the interaction may be limited by the coherence length of the signal laser as in Eq...these cases, the coherence length of the pulsed laser typically limits the effective length of the Brillouin scattering interaction. Long... coherence length lasers with long fiber SBS media have been used to reduce threshold energy, but as indicated at the end of Chapter 2, this has produced

Discrepancies between leg-to-leg bioelectrical Impedance analysis and computerized tomography in abdominal visceral fat measurement.

PubMed

Lu, Hsueh-Kuan; Chen, Yu-Yawn; Yeh, Chinagwen; Chuang, Chih-Lin; Chiang, Li-Ming; Lai, Chung-Liang; Casebolt, Kevin M; Huang, Ai-Chun; Lin, Wen-Long; Hsieh, Kuen-Chang

2017-08-22

The aim of this study was to evaluate leg-to-leg bioelectrical impedance analysis (LBIA) using a four-contact electrode system for measuring abdominal visceral fat area (VFA). The present study recruited 381 (240 male and 141 female) Chinese participants to compare VFA measurements estimated by a standing LBIA system (VFALBIA) with computerized tomography (CT) scanned at the L4-L5 vertebrae (VFA CT ). The total mean body mass index (BMI) was 24.7 ± 4.2 kg/m 2 . Correlation analysis, regression analysis, Bland-Altman plot, and paired sample t-tests were used to analyze the accuracy of the VFA LBIA . For the total subjects, the regression line was VFA LBIA  = 0.698 VFA CT  + 29.521, (correlation coefficient (r) = 0.789, standard estimate of error (SEE) = 24.470 cm 2 , p < 0.001), Lin's correlation coefficient (CCC) was 0.785; and the limit of agreement (LOA; mean difference ±2 standard deviation) ranged from -43.950 to 67.951 cm 2 , LOA% (given as a percentage of mean value measured by the CT) was 48.2%. VFA LBIA and VFA CT showed significant difference (p < 0.001). Collectively, the current study indicates that LBIA has limited potential to accurately estimate visceral fat in a clinical setting.

GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila

PubMed Central

Gowda, Swetha B. M.; Paranjpe, Pushkar D.; Reddy, O. Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich

2018-01-01

Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila. Our findings indicate that targeted down-regulation of the GABAA receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila. PMID:29440493

GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila.

PubMed

Gowda, Swetha B M; Paranjpe, Pushkar D; Reddy, O Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich; VijayRaghavan, K

2018-02-27

Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila Our findings indicate that targeted down-regulation of the GABA A receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila . Copyright © 2018 the Author(s). Published by PNAS.

Limb Lengthening Using the PRECICETM Nail System: Complications and Results

PubMed Central

Wiebking, Ulrich; Liodakis, Emmanouil; Kenawey, Mohamed; Krettek, Christian

2016-01-01

Background Three types of telescopic nails are mainly used for intramedullary limb lengthening nowadays. Despite some important advantages of this new technology (e.g. controlled distraction rate, not restricted availability, possibility to perform accordion maneuvers), few articles exist on clinical results and complications after lengthening with the PRECICETM nail (Ellipse, USA). Objectives The aim of the current study was to describe and analyze the complications associated with lengthening with the PRECICETM nail. Are the problems preventable when using the PRECICE, related to the distraction rate control, the lengthening goals and technique and handling? Methods We retrospectively reviewed the charts of 9 patients operated between 2012 and 2013 with a PRECICETM nail for a leg length discrepancy (LLD). The mean age of the patients was 32 years (range, 17 - 48 years). There were 5 femoral and 4 tibial procedures. The causes of LLD were posttraumatic (n = 5) and congenital (n = 4). The mean LLD was 36.4 ± 11.4 mm. The minimum follow-ups were 2 months (average, 5 months; range, 2 - 9 months). Results The mean distraction rate was 0.5 ± 0.1 mm/day. We observed in 7 patients differences in achieving the lengthening goals (average, 1.6 mm; range, -20.0 - 5.0 mm). Average lengthening was 34.7 ± 10.7 mm. All patients reached normal alignment and normal joint orientation. An unintentional loss of the achieved length during the consolidation phase was noticed in patients with delayed bone healing in two cases. In the first case (loss of 20mm distraction) the nail could be redistracted and the goal length was achieved. In the second case (loss of 10mm distraction) the nail broke shortly after the diagnosis and the nail was exchanged. Conclusions We report of loss of achieved length after lengthening with a telescopic nail. Weight bearing before complete consolidation of the regenerate might be a risk factor for that. Thorough examination of the limb length and careful evaluation of the radiographs are required in the follow-up period. The PRECICE nail system requires the same vigilance like the other intramedullary systems too. PMID:28144605

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs.

PubMed

Spröwitz, Alexander T; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2-3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.

A new biarticular actuator design facilitates control of leg function in BioBiped3.

PubMed

Sharbafi, Maziar Ahmad; Rode, Christian; Kurowski, Stefan; Scholz, Dorian; Möckel, Rico; Radkhah, Katayon; Zhao, Guoping; Rashty, Aida Mohammadinejad; Stryk, Oskar von; Seyfarth, Andre

2016-07-01

Bioinspired legged locomotion comprises different aspects, such as (i) benefiting from reduced complexity control approaches as observed in humans/animals, (ii) combining embodiment with the controllers and (iii) reflecting neural control mechanisms. One of the most important lessons learned from nature is the significant role of compliance in simplifying control, enhancing energy efficiency and robustness against perturbations for legged locomotion. In this research, we investigate how body morphology in combination with actuator design may facilitate motor control of leg function. Inspired by the human leg muscular system, we show that biarticular muscles have a key role in balancing the upper body, joint coordination and swing leg control. Appropriate adjustment of biarticular spring rest length and stiffness can simplify the control and also reduce energy consumption. In order to test these findings, the BioBiped3 robot was developed as a new version of BioBiped series of biologically inspired, compliant musculoskeletal robots. In this robot, three-segmented legs actuated by mono- and biarticular series elastic actuators mimic the nine major human leg muscle groups. With the new biarticular actuators in BioBiped3, novel simplified control concepts for postural balance and for joint coordination in rebounding movements (drop jumps) were demonstrated and approved.

Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs

PubMed Central

Spröwitz, Alexander T.; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

2014-01-01

In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2–3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware. PMID:24639645

Robots in human biomechanics--a study on ankle push-off in walking.

PubMed

Renjewski, Daniel; Seyfarth, André

2012-09-01

In biomechanics, explanatory template models are used to identify the basic mechanisms of human locomotion. However, model predictions often lack verification in a realistic environment. We present a method that uses template model mechanics as a blueprint for a bipedal robot and a corresponding computer simulation. The hypotheses derived from template model studies concerning the function of heel-off in walking are analysed and discrepancies between the template model and its real-world anchor are pointed out. Neither extending the ground clearance of the swinging leg nor an impact reduction at touch-down as an effect of heel lifting was supported by the experiments. To confirm the relevance of the experimental findings, a comparison of robot data to human walking data is discussed and we speculate on an alternative explanation of heel-off in human walking, i.e. that the push-off powers the following leg swing.

A springy pendulum could describe the swing leg kinetics of human walking.

PubMed

Song, Hyunggwi; Park, Heewon; Park, Sukyung

2016-06-14

The dynamics of human walking during various walking conditions could be qualitatively captured by the springy legged dynamics, which have been used as a theoretical framework for bipedal robotics applications. However, the spring-loaded inverted pendulum model describes the motion of the center of mass (CoM), which combines the torso, swing and stance legs together and does not explicitly inform us as to whether the inter-limb dynamics share the springy legged dynamics characteristics of the CoM. In this study, we examined whether the swing leg dynamics could also be represented by springy mechanics and whether the swing leg stiffness shows a dependence on gait speed, as has been observed in CoM mechanics during walking. The swing leg was modeled as a spring-loaded pendulum hinged at the hip joint, which is under forward motion. The model parameters of the loaded mass were adopted from body parameters and anthropometric tables, whereas the free model parameters for the rest length of the spring and its stiffness were estimated to best match the data for the swing leg joint forces. The joint forces of the swing leg were well represented by the springy pendulum model at various walking speeds with a regression coefficient of R(2)>0.8. The swing leg stiffness increased with walking speed and was correlated with the swing frequency, which is consistent with previous observations from CoM dynamics described using the compliant leg. These results suggest that the swing leg also shares the springy dynamics, and the compliant walking model could be extended to better present swing leg dynamics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Radiation characteristics of femtosecond laser-induced plasma channel Vee antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choe, Yun-Sik; Department of Physics, University of Science, Pyongyang, North Korea; Hao, Zuoqiang

A virtual reconfigurable plasma Vee antenna consisting of a set of laser plasma filaments produced by femtosecond laser pulses in air is investigated in this paper. The calculation results show that radiation pattern becomes more complex and gain shows initially rapid rise but gradually saturate as the leg length increases, but the pattern and gain are not seriously affected by the plasma conductivity; particularly, the gain of the Vee antenna with plasma conductivity σ = 100S/m can reach about 80% of that of a copper antenna. Radiation efficiency of the antenna has shown a strong dependence on radius of the antenna leg,more » and an efficiency of 65%, considered to have a proper performance, can be obtained with the channel radius of about 10 mm. Apex angle variation can lead to significant change of the radiation pattern and influence the gain; the best apex angle corresponding to maximal gain and good directivity for the third resonance antenna leg length is found to be at 74° at 600 MHz and σ = 100 S/m. The calculation has shown that at terawatt laser power level, the plasma channel conductivity is close to that of conventional plasma antenna, and peak gain of the Vee antenna is more than 8 dB with a good directivity. In addition, the radiation pattern of special Vee antennas with apex angle 180°-dipole antennas, for first and third resonance leg lengths, is compared and underneath physics of the difference is given. The laser-induced plasma channel antenna is especially suitable for achieving good directivity and gain, which has advantage over conventional plasma antenna with gas discharge tube or metal antenna.« less

Carcass conformation and cut composition of Creole goat from Guadeloupe.

PubMed

Liméa, Léticia; Bocage, Bruno; Arquet, Rémy; Mahieu, Maurice; Alexandre, Gisele

2010-03-01

Carcass data base of 164 Creole male goats was used in order to provide factual data on the carcass conformation. Standardised procedures of carcass measuring and cutting were followed. The European official grid of light lamb is implemented for meat goat in the French West Indies and included five levels. Weights of carcass, cuts and tissues, quality scores and linear measurements were analysed. Feeding system, age at slaughter and weight were taken into account for statistical analysis. There were significant differences among carcass conformation classes (CC) for many traits except for the fat score, leg length and compactness ratio (carcass width on length): 2.2, 34.5 cm and 0.30 on average, respectively. The values of chilled carcass weight and yield and the carcass linear measurements steadily increased until conformation class 4 or 5: 6.7 to 11.2 kg, 49% to 55% and 52.4 to 58.0 cm carcass length. For the weights of carcass cuts, significant differences appeared between two groups: classes 1 and 2 vs. classes 3, 4 and 5. Regardless of the carcass weight, the distribution of prime cuts remained similar. The indices calculated on a weight basis (kg/cm), either for the carcass or the leg, increased significantly (P<0.01): with 54% and 63% difference between the two extreme classes, respectively. The muscle, bone and fat proportions in the shoulder did not vary between CC with 0.72, 0.22 and 0.06, respectively. Corresponding traits in leg were 0.74, 0.23 and 0.03; the last two were different (P<0.05) from class 1 to class 5. The muscle/bone ratios calculated either in shoulder or in leg ranged from 3.1 to 3.6 (P>0.05).

Protection against high intravascular pressure in giraffe legs.

PubMed

Petersen, Karin K; Hørlyck, Arne; Ostergaard, Kristine H; Andresen, Joergen; Broegger, Torbjoern; Skovgaard, Nini; Telinius, Niklas; Laher, Ismael; Bertelsen, Mads F; Grøndahl, Carsten; Smerup, Morten; Secher, Niels H; Brøndum, Emil; Hasenkam, John M; Wang, Tobias; Baandrup, Ulrik; Aalkjaer, Christian

2013-11-01

The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along the artery. Histology of the isolated median artery confirmed dense sympathetic innervation at the narrowing. Structure and contractility of small arteries from muscular beds in the leg and neck were compared. The arteries from the legs demonstrated an increased media thickness-to-lumen diameter ratio, increased media volume, and increased numbers of smooth muscle cells per segment length and furthermore, they contracted more strongly than arteries from the neck (500 ± 49 vs. 318 ± 43 mmHg; n = 6 legs and neck, respectively). Finally, the transient increase in interstitial fluid pressure following injection of saline was 5.5 ± 1.7 times larger (n = 8) in the leg than in the neck. We conclude that 1) tissue compliance in the legs is low; 2) large arteries of the legs function as resistance arteries; and 3) structural adaptation of small muscle arteries allows them to develop an extraordinary tension. All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure.

Measurement and simulation of thermoelectric efficiency for single leg

NASA Astrophysics Data System (ADS)

Hu, Xiaokai; Yamamoto, Atsushi; Ohta, Michihiro; Nishiate, Hirotaka

2015-04-01

Thermoelectric efficiency measurements were carried out on n-type bismuth telluride legs with the hot-side temperature at 100 and 150 °C. The electric power and heat flow were measured individually. Water coolant was utilized to maintain the cold-side temperature and to measure heat flow out of the cold side. Leg length and vacuum pressure were studied in terms of temperature difference across the leg, open-circuit voltage, internal resistance, and heat flow. Finite-element simulation on thermoelectric generation was performed in COMSOL Multiphysics, by inputting two-side temperatures and thermoelectric material properties. The open-circuit voltage and resistance were in good agreement between the measurement and simulation. Much larger heat flows were found in measurements, since they were comprised of conductive, convective, and radiative contributions. Parasitic heat flow was measured in the absence of bismuth telluride leg, and the conductive heat flow was then available. Finally, the maximum thermoelectric efficiency was derived in accordance with the electric power and the conductive heat flow.

Kinematics of an in-parallel actuated manipulator based on the Stewart platform mechanism

NASA Technical Reports Server (NTRS)

Williams, Robert L., II

1992-01-01

This paper presents kinematic equations and solutions for an in-parallel actuated robotic mechanism based on Stewart's platform. These equations are required for inverse position and resolved rate (inverse velocity) platform control. NASA LaRC has a Vehicle Emulator System (VES) platform designed by MIT which is based on Stewart's platform. The inverse position solution is straight-forward and computationally inexpensive. Given the desired position and orientation of the moving platform with respect to the base, the lengths of the prismatic leg actuators are calculated. The forward position solution is more complicated and theoretically has 16 solutions. The position and orientation of the moving platform with respect to the base is calculated given the leg actuator lengths. Two methods are pursued in this paper to solve this problem. The resolved rate (inverse velocity) solution is derived. Given the desired Cartesian velocity of the end-effector, the required leg actuator rates are calculated. The Newton-Raphson Jacobian matrix resulting from the second forward position kinematics solution is a modified inverse Jacobian matrix. Examples and simulations are given for the VES.

Airway compliance and dynamics explain the apparent discrepancy in length adaptation between intact airways and smooth muscle strips.

PubMed

Dowie, Jackson; Ansell, Thomas K; Noble, Peter B; Donovan, Graham M

2016-01-01

Length adaptation is a phenomenon observed in airway smooth muscle (ASM) wherein over time there is a shift in the length-tension curve. There is potential for length adaptation to play an important role in airway constriction and airway hyper-responsiveness in asthma. Recent results by Ansell et al., 2015 (JAP 2014 10.1152/japplphysiol.00724.2014) have cast doubt on this role by testing for length adaptation using an intact airway preparation, rather than strips of ASM. Using this technique they found no evidence for length adaptation in intact airways. Here we attempt to resolve this apparent discrepancy by constructing a minimal mathematical model of the intact airway, including ASM which follows the classic length-tension curve and undergoes length adaptation. This allows us to show that (1) no evidence of length adaptation should be expected in large, cartilaginous, intact airways; (2) even in highly compliant peripheral airways, or at more compliant regions of the pressure-volume curve of large airways, the effect of length adaptation would be modest and at best marginally detectable in intact airways; (3) the key parameters which control the appearance of length adaptation in intact airways are airway compliance and the relaxation timescale. The results of this mathematical simulation suggest that length adaptation observed at the level of the isolated ASM may not clearly manifest in the normal intact airway. Copyright © 2015 Elsevier B.V. All rights reserved.

Carcass and meat quality traits in Nellore and F1 Nellore-Araguaia crosses.

PubMed

Costa, N V; Aboujaoude, C; Vieira, G S; Paiva, V V; Moraes Neto, R A; Gondim, V S; Alves, L R; Torres, M C L; Antunes, R C

2015-05-22

We evaluated and compared carcass traits and meat quality in Nellore cattle and F1 crosses between Nellore and Araguaia, where 17 individuals were from the Nellore group and 19 were ½ Nellore and ½ Araguaia crosses. All animals belonged to the same birth season and were raised in pasture systems under the same nutritional, environmental, and management conditions. When the animals reached slaughter weight, they were taken to an industrial slaughterhouse where food was not provided for 24 h (free access to water); they were then stunned, bled, the leather was removed, and they were eviscerated. The carcasses were weighed (hot weight), kept in chilled storage for approximately 24 h at 4°C, and weighed again to obtain the chilled carcass weight. Carcass yield, carcass length, carcass width, leg length, thigh perimeter, loin eye area (LEA), retail cuts, cooling loss, pH, fat depth, marbling rate, intramuscular fat, color, and shear force were analyzed and sensory analysis of the meat was conducted. Significant differences (P < 0.05) were observed for the following variables: slaughter weight, hot and chilled carcass weights, carcass and leg lengths, thigh perimeter, LEA, retail cuts, and lightness (L*), where the ½ Nellore ½ Araguaia individuals showed higher means for all of these traits, except leg length and L*. Therefore, crossbreeding between Nellore and Araguaia did not affect the meat's sensory characteristics, but contributed to an improvement in carcass traits, providing an alternative for farmers that aim for good meat quality, with a higher meat percentage.

A new species of Nitocra Boeck, 1865 (Harpacticoida, Ameiridae, Ameirinae) from South Africa, with notes on its ecology and remarks on the status of Nitocra sewelli husmanni Kunz, 1976

PubMed Central

Gómez, Samuel; Carrasco, Nicola K.; Morales-Serna, Francisco Neptalí

2012-01-01

Abstract A new species of the genus Nitocra Boeck, 1865, Nitocra taylori sp. n. is described from the St Lucia Estuary, Africa’s largest estuarine lake. It is also suggested that Nitocra sewelli husmanni Kunz, 1976 and Nitocra reducta fluviatilisGalhano, 1968 are granted full species rank as Nitocra husmanni stat. n. Kunz, 1976 and Nitocra fluviatilis stat. n. Galhano, 1968. Nitocra taylori sp. n. appears to be closely related to Nitocra husmanni. Unfortunately, the original description of the micro-characters of the species lacks the detail needed to make reliable comparisons between species of the genus Nitocra. The main differences observed are the number of spinules along the posterior margin of the anal operculum, length ratio of the exopod and endopod of the first swimming leg, shape of the outer spine on the male third endopodal segment of the third swimming leg, number of segments of the male antennule, relative length of the setae on the male baseoendopod of the fifth leg, shape of the male exopod of the fifth leg, relative length of the two setae of the male sixth leg, and shape of the female baseoendopod of the fifth leg. The current distribution of Nitocra taylori sp. n. is limited to the lake part of the estuary, an area which is most severely affected by the current freshwater deprivation crisis. During closed mouth conditions, these regions (South/North Lake and False Bay) are characterized by low water levels, high salinities and high turbidity levels. This suggests that Nitocra taylori sp. n. may favor these environmental conditions and the significant correlations found between the abundance of Nitocra taylori sp. n. and salinity and turbidity confirm this to a degree. Nitocra taylori sp. n. individuals are also able to withstand a wide range of fluctuations. They were recorded at turbidities ranging from 2 to 102 NTU, temperatures from 20.9 to 34.8 ºC and salinity levels ranging from 9.81 to 53.7 psu. However, in the current state of the system, salinity and temperature levels in the northern regions frequently exceed this value. Continued freshwater deprivation may, therefore, further limit the distribution range of this species. PMID:23275743

A new species of Nitocra Boeck, 1865 (Harpacticoida, Ameiridae, Ameirinae) from South Africa, with notes on its ecology and remarks on the status of Nitocra sewelli husmanni Kunz, 1976.

PubMed

Gómez, Samuel; Carrasco, Nicola K; Morales-Serna, Francisco Neptalí

2012-01-01

A new species of the genus Nitocra Boeck, 1865, Nitocra taylorisp. n. is described from the St Lucia Estuary, Africa's largest estuarine lake. It is also suggested that Nitocra sewelli husmanni Kunz, 1976 and Nitocra reducta fluviatilisGalhano, 1968 are granted full species rank as Nitocra husmannistat. n. Kunz, 1976 and Nitocra fluviatilisstat. n. Galhano, 1968. Nitocra taylorisp. n. appears to be closely related to Nitocra husmanni. Unfortunately, the original description of the micro-characters of the species lacks the detail needed to make reliable comparisons between species of the genus Nitocra. The main differences observed are the number of spinules along the posterior margin of the anal operculum, length ratio of the exopod and endopod of the first swimming leg, shape of the outer spine on the male third endopodal segment of the third swimming leg, number of segments of the male antennule, relative length of the setae on the male baseoendopod of the fifth leg, shape of the male exopod of the fifth leg, relative length of the two setae of the male sixth leg, and shape of the female baseoendopod of the fifth leg. The current distribution of Nitocra taylorisp. n. is limited to the lake part of the estuary, an area which is most severely affected by the current freshwater deprivation crisis. During closed mouth conditions, these regions (South/North Lake and False Bay) are characterized by low water levels, high salinities and high turbidity levels. This suggests that Nitocra taylorisp. n. may favor these environmental conditions and the significant correlations found between the abundance of Nitocra taylorisp. n. and salinity and turbidity confirm this to a degree. Nitocra taylorisp. n. individuals are also able to withstand a wide range of fluctuations. They were recorded at turbidities ranging from 2 to 102 NTU, temperatures from 20.9 to 34.8 ºC and salinity levels ranging from 9.81 to 53.7 psu. However, in the current state of the system, salinity and temperature levels in the northern regions frequently exceed this value. Continued freshwater deprivation may, therefore, further limit the distribution range of this species.

The role of intrinsic muscle mechanics in the neuromuscular control of stable running in the guinea fowl

PubMed Central

Daley, Monica A; Voloshina, Alexandra; Biewener, Andrew A

2009-01-01

Here we investigate the interplay between intrinsic mechanical and neural factors in muscle contractile performance during running, which has been less studied than during walking. We report in vivo recordings of the gastrocnemius muscle of the guinea fowl (Numida meleagris), during the response and recovery from an unexpected drop in terrain. Previous studies on leg and joint mechanics following this perturbation suggested that distal leg extensor muscles play a key role in stabilisation. Here, we test this through direct recordings of gastrocnemius fascicle length (using sonomicrometry), muscle–tendon force (using buckle transducers), and activity (using indwelling EMG). Muscle recordings were analysed from the stride just before to the second stride following the perturbation. The gastrocnemius exhibits altered force and work output in the perturbed and first recovery strides. Muscle work correlates strongly with leg posture at the time of ground contact. When the leg is more extended in the drop step, net gastrocnemius work decreases (−5.2 J kg−1versus control), and when the leg is more flexed in the step back up, it increases (+9.8 J kg−1versus control). The muscle's work output is inherently stabilising because it pushes the body back toward its pre-perturbation (level running) speed and leg posture. Gastrocnemius length and force return to level running means by the second stride following the perturbation. EMG intensity differs significantly from level running only in the first recovery stride following the perturbation, not within the perturbed stride. The findings suggest that intrinsic mechanical factors contribute substantially to the initial changes in muscle force and work. The statistical results suggest that a history-dependent effect, shortening deactivation, may be an important factor in the intrinsic mechanical changes, in addition to instantaneous force–velocity and force–length effects. This finding suggests the potential need to incorporate history-dependent muscle properties into neuromechanical simulations of running, particularly if high muscle strains are involved and stability characteristics are important. Future work should test whether a Hill or modified Hill type model provides adequate prediction in such conditions. Interpreted in light of previous studies on walking, the findings support the concept of speed-dependent roles of reflex feedback. PMID:19359369

Impact of the plasma geometry on divertor power exhaust: experimental evidence from TCV and simulations with SolEdge2D and TOKAM3X

NASA Astrophysics Data System (ADS)

Gallo, A.; Fedorczak, N.; Elmore, S.; Maurizio, R.; Reimerdes, H.; Theiler, C.; Tsui, C. K.; Boedo, J. A.; Faitsch, M.; Bufferand, H.; Ciraolo, G.; Galassi, D.; Ghendrih, P.; Valentinuzzi, M.; Tamain, P.; the EUROfusion MST1 Team; the TCV Team

2018-01-01

A deep understanding of plasma transport at the edge of magnetically confined fusion plasmas is needed for the handling and control of heat loads on the machine first wall. Experimental observations collected on a number of tokamaks over the last three decades taught us that heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two scale lengths for the scrape-off layer (SOL) transport, separately characterizing the main SOL ({λ }q) and the divertor SOL (S q ). In this work we challenge the current interpretation of these two scale lengths as well as their dependence on plasma parameters by studying the effect of divertor geometry modifications on heat exhaust in the Tokamak à Configuration Variable. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg in lower single null, Ohmic, L-mode discharges. Efforts to reproduce this experimental finding with both diffusive (SolEdge2D-EIRENE) and turbulent (TOKAM3X) modelling tools confirm the validity of a diffusive approach for simulating heat flux profiles in more traditional, short leg, configurations while highlighting the need of a turbulent description for modified, long leg, ones in which strongly asymmetric divertor perpendicular transport develops.

[Is it too late to start orthopedic treatment for idiopathic scoliosis with Risser scores of 4?].

PubMed

Avellanet, M; González Viejo, M-A; Sáenz, A; Hijós, M-E

2006-12-01

Orthopaedic treatment for idiopathic scoliosis in adolescence is indicated with a curve of > or =20 degrees and a Risser score< or =4, because progression of curve is low with Risser scores >4. We present the case of a young man with a left lumbar idiopathic scoliosis (T12-L4) with a curve of 10 degrees, which was stable from 13 years (Risser 0) to 16 years old (Risser 4). The scoliosis progressed quickly after a Risser score of 4 was achieved. The man had been wearing a lift on the left foot since he was 13, because of a leg length discrepancy, and had been under clinical and radiological monitoring. When the boy reached 17 years, the scoliosis rapidly progressed, to a curve of 22 degrees and a Risser score of >4. The scoliosis was effectively treated with a Boston brace. At 20 years, the Risser score was 5, and the left lumbar curve was 13 degrees after discontinuing the use of the brace. To our knowledge, no scientific reference indicates a time limit to orthopaedic treatment for idiopathic adolescent scoliosis. Despite the experts' recommendations, a brace might be indicated with a Risser score > or =4 to stop the progression of the curve.

Passive Dynamics in the Control of Gymnastic Maneuvers.

DTIC Science & Technology

1995-03-01

1992 and 1994 winter Olympics, the nal jump performed by the men’s champion freestyle skier was a quadruple twisting, triple somersault. In the per...ltd. The computation of the desired leg length depends upon knowledge of robot pa- rameters such as inertia and leg mass. However, since the process is...Accommodating Landing Time Errors A limitation of the tuck servo strategy is its dependence upon accurate knowledge of the time until landing. With somersault

Laboratory on Legs: An Architecture for Adjustable Morphology with Legged Robots

DTIC Science & Technology

2012-04-01

fit within the body of the robot. Additional capabilities will largely depend upon a given activity, and should be easily reconfigurable to maximize...mobile robots, the essential units of actuation, computation, and sensing must be designed to fit within the body of the robot. Additional...PackBot,36 among others. Two parallel rails, 40 cm long and spaced at a center-to-center distance of 14 cm, span the length of the each robot’s body

Selection on an extreme weapon in the frog-legged leaf beetle (Sagra femorata).

PubMed

O'Brien, Devin M; Katsuki, Masako; Emlen, Douglas J

2017-11-01

Biologists have been fascinated with the extreme products of sexual selection for decades. However, relatively few studies have characterized patterns of selection acting on ornaments and weapons in the wild. Here, we measure selection on a wild population of weapon-bearing beetles (frog-legged leaf beetles: Sagra femorata) for two consecutive breeding seasons. We consider variation in both weapon size (hind leg length) and in relative weapon size (deviations from the population average scaling relationship between hind leg length and body size), and provide evidence for directional selection on weapon size per se and stabilizing selection on a particular scaling relationship in this population. We suggest that whenever growth in body size is sensitive to external circumstance such as nutrition, then considering deviations from population-level scaling relationships will better reflect patterns of selection relevant to evolution of the ornament or weapon than will variation in trait size per se. This is because trait-size versus body-size scaling relationships approximate underlying developmental reaction norms relating trait growth with body condition in these species. Heightened condition-sensitive expression is a hallmark of the exaggerated ornaments and weapons favored by sexual selection, yet this plasticity is rarely reflected in the way we think about-and measure-selection acting on these structures in the wild. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Effect of Leg-to-Body Ratio on Body Shape Attractiveness.

PubMed

Kiire, Satoru

2016-05-01

Recent studies have examined various aspects of human physical attractiveness. Attractiveness is considered an evolved psychological mechanism acquired via natural selection because an attractive body reflects an individual's health and fertility. The length of the legs is an often-emphasized aspect of attractiveness and has been investigated using the leg-to-body ratio (LBR), which reflects nutritional status of the infant, health status, fecundity, and other factors that are predictive of physical fitness. However, previous studies of leg length and physical fitness have produced mixed results. The present study investigated the relationship between LBR, defined as the height to perineum divided by total height, and perceived attractiveness. Three-dimensional stimuli (11 male and 11 female) were constructed with various LBR features. Each stimulus was rated by 40 women and 40 men in Japan on a 7-point scale. The results showed that the values closest to the average LBRs were rated as the most attractive. Furthermore, by fitting a quadratic curve on the relationship between attractiveness and LBR, an inverted U-shaped curve with the peak located at the average LBR was observed. In addition, high LBR values were rated as more attractive in females, whereas the opposite was true for males. These results suggest that average LBR is indicative of good health and good reproductive potential, whereas more extreme values are avoided because they could be indicative of diseases and other maladaptive conditions.

Trunk orientation causes asymmetries in leg function in small bird terrestrial locomotion.

PubMed

Andrada, Emanuel; Rode, Christian; Sutedja, Yefta; Nyakatura, John A; Blickhan, Reinhard

2014-12-22

In contrast to the upright trunk in humans, trunk orientation in most birds is almost horizontal (pronograde). It is conceivable that the orientation of the heavy trunk strongly influences the dynamics of bipedal terrestrial locomotion. Here, we analyse for the first time the effects of a pronograde trunk orientation on leg function and stability during bipedal locomotion. For this, we first inferred the leg function and trunk control strategy applied by a generalized small bird during terrestrial locomotion by analysing synchronously recorded kinematic (three-dimensional X-ray videography) and kinetic (three-dimensional force measurement) quail locomotion data. Then, by simulating quail gaits using a simplistic bioinspired numerical model which made use of parameters obtained in in vivo experiments with real quail, we show that the observed asymmetric leg function (left-skewed ground reaction force and longer leg at touchdown than at lift-off) is necessary for pronograde steady-state locomotion. In addition, steady-state locomotion becomes stable for specific morphological parameters. For quail-like parameters, the most common stable solution is grounded running, a gait preferred by quail and most of the other small birds. We hypothesize that stability of bipedal locomotion is a functional demand that, depending on trunk orientation and centre of mass location, constrains basic hind limb morphology and function, such as leg length, leg stiffness and leg damping. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

[Case-control study on methods of limb length control in hip arthroplasty].

PubMed

Zhang, Yang-yang; Zuo, Jian-lin; Gao, Zhong-li

2016-02-01

To introduce a new measuring tool for measuring postoperative limb length exactly, and to provide a convenient and effective method to control limb length after total hip replacement. From January 2013 to September 2014, 102 patients undergoing primary unilateral hip replacement were divided into two groups: experimental group and control group. There were 51 patients in the experimental group, including 25 males and 26 females, ranging in age from 37 to 92 years old, with an average of 60.41 years old. The patients in experimental group were treated with new method to control limb length. Other 51 patients in the control group, including 27 males and 24 females, ranging in age from 35 to 87 years old, with an average of 61.00 years old. The patients in the control group were treated with normal methods such as shuck test or limb touching. All the patients were operated by the same experienced surgeon. In the experimental group,total hip arthroplasties (THA) were performed on 35 patients with avascular necrosis of the femoral head or femoral neck fracture, and 16 patients were treated with hemiarthroplasty (HA). In the control group, 38 patients received THA and 13 patients received HA. On the anterior-posterior X-ray radiograph, several indexes were measured as follows: the distance of bilateral femoral offset (a), the height from tip of great trochanter to the rotation center of the femoral head (b) and the vertical distance between the top of the minor trochanter and the two tear drops line (c). The leg length discrepancy can be assessed with three parameters as follows: d1, the absolute value of the difference between the bilateral a values; d2, the difference between the bilateral b values; d3, the difference between the bilateral c values. The SPSS 21.0 was applied for the statistical analysis. In the experimental and control groups, d1 were 4.49 mm and 7.32 mm (P = 0.013); d2 were 2.37 mm and 4.32 mm (P = 0.033); d3 were 3.32 mm and 6.08 mm (P = 0.031). The values of d1, d2 and d3 in the experimental group were significant smaller than those in the control group. The new measuring tool and method can be used to control the limb length and offset effectively during operation.

Profiling Isokinetic Strength by Leg Preference and Position in Rugby Union Athletes.

PubMed

Brown, Scott R; Brughelli, Matt; Bridgeman, Lee A

2016-05-01

Muscle imbalances aid in the identification of athletes at risk for lower-extremity injury. Little is known regarding the influence that leg preference or playing position may have on lower-extremity muscle strength and asymmetry. To investigate lower-extremity strength profiles in rugby union athletes and compare isokinetic knee- and hip-strength variables between legs and positions. Thirty male academy rugby union athletes, separated into forwards (n = 15) and backs (n = 15), participated in this cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque, angle of peak torque, and strength ratios of the preferred and nonpreferred legs during seated knee extension/flexion and supine hip extension/flexion at 60°/s. Backs were older (ES = 1.6) but smaller in stature (ES = -0.47) and body mass (ES = -1.3) than the forwards. The nonpreferred leg was weaker than the preferred leg for forwards during extension (ES = -0.37) and flexion (ES = -0.21) actions and for backs during extension (ES = -0.28) actions. Backs were weaker at the knee than forwards in the preferred leg during extension (ES = -0.50) and flexion (ES = -0.66) actions. No differences were observed in strength ratios between legs or positions. Backs produced peak torque at longer muscle lengths in both legs at the knee (ES = -0.93 to -0.94) and hip (ES = -0.84 to -1.17) than the forwards. In this sample of male academy rugby union athletes, the preferred leg and forwards displayed superior strength compared with the nonpreferred leg and backs. These findings highlight the importance of individualized athletic assessments to detect crucial strength differences in male rugby union athletes.

Jumping of water striders on water

NASA Astrophysics Data System (ADS)

Yang, Eunjin; Son, Jaehak; Jablonski, Piotr; Kim, Ho-Young

2012-11-01

Small insects such as water striders, springtails, fishing spiders freely move on water by adopting various modes of locomotion, such as rowing, galloping, jumping and meniscus-climbing. As the physics of jumping have not yet been fully understood among those ways of semi-aquatic propulsion, here we present the results of a combined experimental and theoretical investigation of the dynamics of water striders leaping off water. We first image and analyze the trajectories of the legs and body of jumping water striders of three different species with a high-speed camera. We then theoretically compute the forces acting on the body by considering the capillary interaction between the flexible legs and deforming water meniscus. Our theory enables us to predict the maximum take-off speed for given leg lengths. The experimental measurements suggest that the water striders drive their legs near the optimal speed to gain the maximum take-off speed.

Pressurized water nuclear reactor system with hot leg vortex mitigator

DOEpatents

Lau, Louis K. S.

1990-01-01

A pressurized water nuclear reactor system includes a vortex mitigator in the form of a cylindrical conduit between the hot leg conduit and a first section of residual heat removal conduit, which conduit leads to a pump and a second section of residual heat removal conduit leading back to the reactor pressure vessel. The cylindrical conduit is of such a size that where the hot leg has an inner diameter D.sub.1, the first section has an inner diameter D.sub.2, and the cylindrical conduit or step nozzle has a length L and an inner diameter of D.sub.3 ; D.sub.3 /D.sub.1 is at least 0.55, D.sub.2 is at least 1.9, and L/D.sub.3 is at least 1.44, whereby cavitation of the pump by a vortex formed in the hot leg is prevented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simone, Brittany A.; Ly, David; Savage, Jason E.

Purpose: Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed. Methods and Materials: To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days aftermore » irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs. Results: Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met. Conclusions: Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation.« less

microRNA alterations driving acute and late stages of radiation-induced fibrosis in a murine skin model.

PubMed

Simone, Brittany A; Ly, David; Savage, Jason E; Hewitt, Stephen M; Dan, Tu D; Ylaya, Kris; Shankavaram, Uma; Lim, Meng; Jin, Lianjin; Camphausen, Kevin; Mitchell, James B; Simone, Nicole L

2014-09-01

Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed. To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days after irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs. Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met. Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation. Published by Elsevier Inc.

[Treatment of pediatric distal femur fractures by external fixator combined with limited internal fixation].

PubMed

Wei, Sheng-wang; Shi, Zhan-ying; Hu, Ju-zheng; Wu, Hao

2016-03-01

To discuss the clinical effects of external fixator combined with limited internal fixation in the treatment of pediatric distal femur fractures. From January 2008 to June 2014, 17 children of distal femur fractures were treated by external fixator combined with limited internal fixation. There were 12 males and 5 females, aged from 6 to 13 years old with an average of 10.2 years, ranged in the course of disease from 1 h to 2 d. Preoperative diagnoses were confirmed by X-ray films in all children. There were 11 patients with supracondylar fracture , and 6 patients with intercondylar comminuted fracture. According to AO/ASIF classification, 9 fractures were type A1, 5 cases were type A2,and 3 cases were type C1. The intraoperative and postoperative complications, postoperative radiological examination, lower limbs length and motion of knee joints were observed. Knee joint function was assessed by KSS score. All the patients were followed up from 6 to 38 months with an average of 24.4 months. No nerve or blood vessel injury was found. One case complicated with the external fixation loosening, 2 cases with the infection of pin hole and 3 cases with the leg length discrepancy. Knee joint mobility and length measurement (compared with the contralateral), the average limited inflexion was 10 degrees (0 degrees to 20 degrees), the average limited straight was 4 degrees (0 degrees to 10), the average varus or valgus angle was 3 degrees (0 degrees to 5 degrees). KSS of the injured side was (96.4 +/- 5.0) points at final follow-up, 16 cases got excellent results and 1 good. All fractures obtained healing and no epiphyseal closed early was found. External fixator combined with limited internal fixation has advantages of simple operation, reliable fixation, early functional exercise in treating pediatric distal femurs fractures.

Rate of Unverifiable Publications Among Ophthalmology Residency Applicants Invited to Interview.

PubMed

Tamez, Heather M; Tauscher, Robert; Brown, Eric N; Wayman, Laura; Mawn, Louise A

2018-04-19

Unverifiable publications in applications for ophthalmology residencies could be a serious concern if they represent publication dishonesty. To determine the rate of unverifiable publications among applicants offered an interview. Retrospective review of 322 ophthalmology residency applications for entering classes 2012 to 2017 at Vanderbilt University School of Medicine, Nashville, Tennessee. Full-length publications reported in the applications were searched in PubMed, Google, Google Scholar, and directly on the journal's website. Applications were deemed unverifiable if there was no record of the publication by any of these means or if substantial discrepancies existed, such as incorrect authorship, incorrect journal, or a meaningful discrepancy in title or length (full-length article vs abstract). Inability to locate publication with search, incorrect author position, applicant not listed as an author, article being an abstract and not a published paper, substantial title discrepancy suggesting an alternative project, and incorrect journal. Of the 322 applicants offered interviews during the 6-year study period, 22 (6.8%) had 24 unverifiable publications. Two hundred thirty-nine of these applicants (74.2%) reported at least 1 qualifying publication; of this group, 22 (9.2%) had an unverifiable publication. The applications with unverifiable publications were evenly distributed across the years of the study (range, 2-6 per cycle; Pearson χ25 = 3.65; P = .60). Two applicants had 2 unverifiable publications each. Two of the 22 applicants (9.1%) with unverifiable publications were graduates of medical schools outside the United States. Among the unverifiable publications, the most common reason was inability to locate the publication (13 [54%]). Additional issues included abstract rather than full-length publication (5 [20.8%]), incorrect author position (4 [16.7%]), applicant not listed as an author on the publication (1 [4.2%]), and substantial title discrepancy (1 [4.2%]). One listed publication had an incorrect author position and incorrect journal (1 [4.2%]). Unverifiable publications among ophthalmology residency applicants is a persistent problem. Possible strategies to modify the review process include asking applicants to provide copies of their full-length works or the relevant PMCID (PubMed Central reference number) or DOI (digital object identifier) for their publications.

Ilizarov bone transport versus fibular graft for reconstruction of tibial bone defects in children.

PubMed

Abdelkhalek, Mostafa; El-Alfy, Barakat; Ali, Ayman M

2016-11-01

The aim of this study was to compare the results of treatment of segmental tibial defects in the pediatric age group using an Ilizarov external fixator versus a nonvascularized fibular bone graft. This study included 24 patients (age range from 5.5 to 15 years) with tibial bone defects: 13 patients were treated with bone transport (BT) and 11 patients were treated with a nonvascularized fibular graft (FG). The outcome parameters were bone results (union, deformity, infection, leg-length discrepancy) and functional results: external fixation index and external fixation time. In group A (BT), one patient developed refracture at the regenerate site, whereas, in group B (FG), after removal of the external fixator, one of the FGs developed a stress fracture. The external fixator time in group A was 10.7 months (range 8-14.5) versus 7.8 months (range 4-11.5 months) in group B (FG). In group A (BT), one patient had a limb-length discrepancy (LLD), whereas, in group B (FG), three patients had LLD. The functional and bone results of the Ilizarov BT technique were excellent in 23.1 and 30.8%, good in 38.5 and 46.2, fair in 30.8 and 15.4, and poor in 7.6 and 7.6%, respectively. The poor functional result was related to the poor bone result because of prolonged external fixator time resulting in significant pain, limited ankle motion, whereas the functional and bone results of fibular grafting were excellent in 9.1 and 18.2%, good in 63.6 and 45.5%, fair in 18.2 and 27.2%, and poor in 9.1 and 9.1%, respectively. Segmental tibial defects can be effectively treated with both methods. The FG method provides satisfactory results, with early removal of the external fixator. However, it had a limitation in patients with severe infection and those with LLD. Also, it requires a long duration of limb bracing until adequate hypertrophy of the graft. The Ilizarov method has the advantages of early weight bearing, treatment of postinfection bone defect in a one-stage surgery, and the possibility to treat the associated LLD. However, it has a long external fixation time.

Quantification of facial and smile esthetics.

PubMed

Koidou, Vasiliki P; Chatzopoulos, Georgios S; Rosenstiel, Stephen F

2018-02-01

Whether deviations in alignment discrepancy, width-to-length ratio, application of the golden proportion, or number of teeth revealed in smile affect attractiveness is yet unknown. The purpose of this analytical study was to quantify dental and facial esthetics to determine whether individuals identified as having superior smiles display differences in alignment discrepancies (angulation between interpupillary and commissure line); width-to-length ratios of maxillary anterior teeth; application of the golden proportion (approximately 1.618:1); and number of teeth revealed in an animated smile when compared with an average population. An Internet search for "best smile" and "celebrity" identified 108 celebrities. Photographs showing smiles within 10 degrees of a frontal view were collected, while photographs of dental students were used for the control group. Alignment discrepancies, widths and lengths of the anterior teeth, and number of teeth revealed in an animated smile were measured with photo-editing software, and ratios were calculated. The groups were compared with repeated-measures ANOVA, the Mann-Whitney U test, and the Wilcoxon signed-rank test (α=.05). Usable photographs were obtained for 90 celebrities (58 women, 32 men) and compared with photographs of 97 dental students (54 women, 43 men). Statistically significant differences were found for alignment discrepancies (celebrities 0.97, students 1.25, P=.034) and for the number of teeth displayed (P=.049); 22.2% of the celebrities revealed 12 teeth, versus 6.2% of the students. In both groups, significant differences from the golden ratio (1.618:1) for the width of the central incisor/lateral incisor right and left and for the width of the lateral incisor/canine right and left were observed through 95% confidence intervals. Sex and left-right were nonsignificant factors. Celebrities identified as having a best smile had smaller mean alignment discrepancies and revealed a greater number of teeth in an animated smile than dental students. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

PubMed Central

Sims, David T.; Onambélé-Pearson, Gladys L.; Burden, Adrian; Payton, Carl; Morse, Christopher I.

2018-01-01

The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption (V͘O2) and metabolic cost (C) when walking at running compared to those of average stature (controls). The aim of this study was to measure submaximal V͘O2 and C during a range of set walking speeds (SWS; 0.56 – 1.94 m⋅s-1, increment 0.28 m⋅s-1), set running speeds (SRS; 1.67 – 3.33 m⋅s-1, increment 0.28 m⋅s-1) and a self-selected walking speed (SSW). V͘O2 and C was scaled to total body mass (TBM) and fat free mass (FFM) while gait speed was scaled to leg length using Froude’s number (Fr). Achondroplasic V͘O2TBM and V͘O2FFM were on average 29 and 35% greater during SWS (P < 0.05) and 12 and 18% higher during SRS (P < 0.05) than controls, respectively. Achondroplasic CTBM and CFFM were 29 and 33% greater during SWS (P < 0.05) and 12 and 18% greater during SRS (P < 0.05) than controls, respectively. There was no difference in SSW V͘O2TBM or V͘O2FFM between groups (P > 0.05), but CTBM and CFFM at SSW were 23 and 29% higher (P < 0.05) in the Achondroplasic group compared to controls, respectively. V͘O2TBM and V͘O2FFM correlated with Fr for both groups (r = 0.984 – 0.999, P < 0.05). Leg length accounted for the majority of the higher V͘O2TBM and V͘O2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic CTBM and CFFM at all speeds compared to controls. New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups. PMID:29720948

Effects of a salsa dance training on balance and strength performance in older adults.

PubMed

Granacher, Urs; Muehlbauer, Thomas; Bridenbaugh, Stephanie A; Wolf, Madeleine; Roth, Ralf; Gschwind, Yves; Wolf, Irene; Mata, Rui; Kressig, Reto W

2012-01-01

Deficits in static and particularly dynamic postural control and force production have frequently been associated with an increased risk of falling in older adults. The objectives of this study were to investigate the effects of salsa dancing on measures of static/dynamic postural control and leg extensor power in seniors. Twenty-eight healthy older adults were randomly assigned to an intervention group (INT, n = 14, age 71.6 ± 5.3 years) to conduct an 8-week progressive salsa dancing programme or a control group (CON, n = 14, age 68.9 ± 4.7 years). Static postural control was measured during one-legged stance on a balance platform and dynamic postural control was obtained while walking on an instrumented walkway. Leg extensor power was assessed during a countermovement jump on a force plate. Programme compliance was excellent with participants of the INT group completing 92.5% of the dancing sessions. A tendency towards an improvement in the selected measures of static postural control was observed in the INT group as compared to the CON group. Significant group × test interactions were found for stride velocity, length and time. Post hoc analyses revealed significant increases in stride velocity and length, and concomitant decreases in stride time. However, salsa dancing did not have significant effects on various measures of gait variability and leg extensor power. Salsa proved to be a safe and feasible exercise programme for older adults accompanied with a high adherence rate. Age-related deficits in measures of static and particularly dynamic postural control can be mitigated by salsa dancing in older adults. High physical activity and fitness/mobility levels of our participants could be responsible for the nonsignificant findings in gait variability and leg extensor power. Copyright © 2012 S. Karger AG, Basel.

Cupiennius salei: biomechanical properties of the tibia-metatarsus joint and its flexing muscles.

PubMed

Siebert, Tobias; Weihmann, Tom; Rode, Christian; Blickhan, Reinhard

2010-02-01

Hunting spiders are well adapted to fast locomotion. Space saving hydraulic leg extension enables leg segments, which consist almost soley of flexor muscles. As a result, the muscle cross sectional area is high despite slender legs. Considering these morphological features in context with the spider's segmented C-shaped legs, these specifics might influence the spider's muscle properties. Moreover, these properties have to be known for modeling of spider locomotion. Cupiennius salei (n = 5) were fixed in a metal frame allowing exclusive flexion of the tibia-metatarsus joint of the second leg (counted from anterior). Its flexing muscles were stimulated supramaximally using needle electrodes. Accounting for the joint geometry, the force-length and the force-velocity relationships were determined. The spider muscles produce 0.07 N cm maximum isometric moment (corresponding to 25 N/cm(2) maximum stress) at 160 degrees tibia-metatarsus joint angle. When overextended to the dorsal limit at approximately 200 degrees , the maximum isometric moments decrease to 72%, and, when flexed to the ventral hinge stop at 85 degrees , they drop to 11%. The force-velocity relation shows the typical hyperbolic shape. The mean maximum shortening velocity is 5.7 optimum muscle lengths per second and the mean curvature (a/F (iso)) of the Hill-function is 0.34. The spider muscle's properties which were determined are similar to those of other species acting as motors during locomotion (working range, curvature of Hill hyperbola, peak power at the preferred speeds), but they are relatively slow. In conjunction with the low mechanical advantage (muscle lever/load arm), the arrangement of three considerably actuated joints in series may nonetheless enable high locomotion velocities.

The hybrid mass-spring pendulum model of human leg swinging: stiffness in the control of cycle period.

PubMed

Obusek, J P; Holt, K G; Rosenstein, R M

1995-07-01

Human leg swinging is modeled as the harmonic motion of a hybrid mass-spring pendulum. The cycle period is determined by a gravitational component and an elastic component, which is provided by the attachment of a soft-tissue/muscular spring of variable stiffness. To confirm that the stiffness of the spring changes with alterations in the inertial properties of the oscillator and that stiffness is relevant for the control of cycle period, we conducted this study in which the simple pendulum equivalent length was experimentally manipulated by adding mass to the ankle of a comfortably swinging leg. Twenty-four young, healthy adults were videotaped as they swung their right leg under four conditions: no added mass and with masses of 2.27, 4.55, and 6.82kg added to the ankle. Strong, linear relationships between the acceleration and displacement of the swinging leg within subjects and conditions were found, confirming the motion's harmonic nature. Cycle period significantly increased with the added mass. However, the observed increases were not as large as would be predicted by the induced changes in the gravitational component alone. These differences were interpreted as being due to increases in the active muscular stiffness. Significant linear increases in the elastic component (and hence stiffness) were demonstrated with increases in the simple pendulum equivalent length in 20 of the individual subjects, with r2 values ranging between 0.89 and 0.99. Significant linear relationships were also demonstrated between the elastic and gravitational components in 22 subjects, with individual r2 values between 0.90 and 0.99.(ABSTRACT TRUNCATED AT 250 WORDS)

Asymmetry in gait pattern following bicondylar tibial plateau fractures-A prospective one-year cohort study.

PubMed

Elsoe, Rasmus; Larsen, Peter

2017-07-01

Despite the high number of studies evaluating outcomes following tibial plateau fractures, the literature lacks studies including the objective assessment of gait pattern. The purpose of the present study was to evaluate asymmetry in gait patterns at 12 months after frame removal following ring fixation of a tibial plateau fracture. The study design was a prospective cohort study. The primary outcome measurement was the gait patterns 12 months after frame removal measured with a pressure-sensitive mat. The mat registers footprints and present gait speed, cadence, as well as temporal and spatial parameters of the gait cycle. Gait patterns were compared to a healthy reference population. Twenty-three patients were included with a mean age of 54.4 years (32-78 years). Patients presented with a shorter step-length of the injured leg compared to the non-injured leg (asymmetry of 11.3%). Analysis of single-support showed shorter support time of the injured leg compared to the non-injured leg (asymmetry of 8.7%). Moreover, analysis of swing-time showed increased swing-time of the injured leg (asymmetry of 8.9%). Compared to a healthy reference population, increased asymmetry in all gait patterns was observed. The association between asymmetry and health-related quality of life (HRQOL) showed moderate associations (single-support: R=0.50, P=0.03; step-length: R=0.43, P=0.07; swing-time: R=0.46, P=0.05). Compared to a healthy reference population, gait asymmetry is common 12 months after frame removal in patients treated with external ring fixation following a tibial plateau fracture of the tibia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increased delivery stride length places greater loads on the ankle joint in elite male cricket fast bowlers.

PubMed

Spratford, Wayne; Hicks, Amy

2014-01-01

The purpose of this study was to investigate the effect stride length has on ankle biomechanics of the leading leg with reference to the potential risk of injury in cricket fast bowlers. Ankle joint kinematic and kinetic data were collected from 51 male fast bowlers during the stance phase of the final delivery stride. The bowling cohort comprised national under-19, first class and international-level athletes. Bowlers were placed into either Short, Average or Long groups based on final stride length, allowing statistical differences to be measured. A multivariate analysis of variance with a Bonferroni post-hoc correction (α = 0.05) revealed significant differences between peak plantarflexion angles (Short-Long P = 0.005, Average and Long P = 0.04) and negative joint work (Average-Long P = 0.026). This study highlighted that during fast bowling the ankle joint of the leading leg experiences high forces under wide ranges of movement. As stride length increases, greater amounts of negative work and plantarflexion are experienced. These increases place greater loads on the ankle joint and move the foot into positions that make it more susceptible to injuries such as posterior impingement syndrome.

Evaluation of different captive bolt lengths and breed influence upon post-stun hind limb and forelimb activity in fed cattle at a commercial slaughter facility.

PubMed

Martin, Miriam S; Kline, Helen C; Wagner, Dana R; Alexander, Lacey R; Edwards-Callaway, Lily N; Grandin, Temple

2018-05-03

The objective of this study was to assess the effects of captive bolt length and breed type on post-stun leg activity in cattle. A total of 2850 Holstein (HOL) and non-Holstein British/Continental bred (NHOL) steers and heifers were observed post-stunning at a large commercial slaughter facility. A pneumatically powered penetrating captive bolt stunner was used with three different bolt lengths: CON, 15.24 cm; MED, 16.51 cm; and LON, 17.78 cm. Hind limb kicking, forelimb activity, take away belt stops, carcass swing and number of knife sticks during exsanguination were recorded for each animal from video recording. Hind limb and forelimb kicks observed ranged from 0 to 25 and 0 to 8, respectively. Analysis of post-stun hind limb and forelimb activity indicated that increasing pneumatically powered penetrating captive bolt length does not decrease post-stun leg activity. There was a higher percentage of cattle experiencing take away belt stops and carcass swing in HOL as compared with NHOL. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Swimming Speed of The Breaststroke Kick

PubMed Central

Strzała, Marek; Krężałek, Piotr; Kaca, Marcin; Głąb, Grzegorz; Ostrowski, Andrzej; Stanula, Arkadiusz; Tyka, Aleksander

2012-01-01

The breaststroke kick is responsible for a considerable portion of the forward propulsion in breaststroke swimming. The aim of this study was to measure selected anthropometric variables and functional properties of a swimmer’s body: length of body parts; functional range of motion in the leg joints and anaerobic power of the lower limbs. Chosen kinematic variables useful in the evaluation of swimming performance in the breaststroke kick were evaluated. In the present research, swimming speed using breaststroke kicks depended to the largest extent on anaerobic endurance (0.46, p < 0.05 partial correlations with age control). In addition, knee external rotation and swimming technique index had an impact on swimming speed and kick length (both partial correlations with age control 0.35, p < 0.08). A kinematic analysis of the breaststroke kick hip displacement compatible with horizontal body displacement was significantly negatively correlated with foot slip in the water opposite to body displacement (partial correlations: with leg length control −0.43, p < 0.05; with shank length control −0.45, p < 0.05, respectively). Present research and measurements of selected body properties, physical endurance and kinematic movement analysis may help in making a precise determination of an athlete’s talent for breaststroke swimming. PMID:23486737

Genome-wide Analysis of Body Proportion Classifies Height-Associated Variants by Mechanism of Action and Implicates Genes Important for Skeletal Development

PubMed Central

Chan, Yingleong; Salem, Rany M.; Hsu, Yu-Han H.; McMahon, George; Pers, Tune H.; Vedantam, Sailaja; Esko, Tonu; Guo, Michael H.; Lim, Elaine T.; Franke, Lude; Smith, George Davey; Strachan, David P.; Hirschhorn, Joel N.

2015-01-01

Human height is a composite measurement, reflecting the sum of leg, spine, and head lengths. Many common variants influence total height, but the effects of these or other variants on the components of height (body proportion) remain largely unknown. We studied sitting height ratio (SHR), the ratio of sitting height to total height, to identify such effects in 3,545 African Americans and 21,590 individuals of European ancestry. We found that SHR is heritable: 26% and 39% of the total variance of SHR can be explained by common variants in European and African Americans, respectively, and global European admixture is negatively correlated with SHR in African Americans (r2 ≈ 0.03). Six regions reached genome-wide significance (p < 5 × 10−8) for association with SHR and overlapped biological candidate genes, including TBX2 and IGFBP3. We found that 130 of 670 height-associated variants are nominally associated (p < 0.05) with SHR, more than expected by chance (p = 5 × 10−40). At these 130 loci, the height-increasing alleles are associated with either a decrease (71 loci) or increase (59 loci) in SHR, suggesting that different height loci disproportionally affect either leg length or spine/head length. Pathway analyses via DEPICT revealed that height loci affecting SHR, and especially those affecting leg length, show enrichment of different biological pathways (e.g., bone/cartilage/growth plate pathways) than do loci with no effect on SHR (e.g., embryonic development). These results highlight the value of using a pair of related but orthogonal phenotypes, in this case SHR with height, as a prism to dissect the biology underlying genetic associations in polygenic traits and diseases. PMID:25865494

Broiler embryo bone development is influenced by incubator temperature, oxygen concentration and eggshell conductance at the plateau stage in oxygen consumption.

PubMed

Oviedo-Rondón, E O; Small, J; Wineland, M J; Christensen, V L; Mozdziak, P S; Koci, M D; Funderburk, S V L; Ort, D T; Mann, K M

2008-11-01

1. Four experiments were conducted to evaluate the effects of temperature (TEM) and oxygen (O(2)) concentrations during the last 4 d of incubation on bone development. Fertile eggs from two strains were obtained that either exhibited Low or High eggshell conductance (G). 2. Four experimental cabinets provided either four TEM (36, 37, 38 or 39 degrees C) or four O(2) concentrations (17, 19, 21 or 23% O(2)). Data were analysed as a 2 x 2 factorial design. In the fourth experiment, two temperatures (36 and 39 degrees C), two O(2) concentrations (17 and 23%) and the same Low and High G strains were evaluated in a 2 x 2 x 2 factorial design. 3. Body weights (BW) and residual yolks were obtained, both legs were dissected. Femur, tibia and shank weights, length and thickness were recorded. Relative asymmetry (RA) of each leg section was calculated. 4. The results indicated that elevated TEM during incubation increased RA between the two legs, mainly in the Low G strain. Chickens at the lowest O(2) concentrations had lighter and shorter tibias, lighter shanks, and increased RA of femur length compared to chickens in the 23% O(2). In the fourth experiment no interactions were observed between O(2) and TEM. High TEM depressed BW of Low G broilers, but no significant effect of treatments was observed on BW of High G broilers. Nevertheless, the high TEM or low O(2) independently caused reduced femur and tibia weights and length, shank length and thickness, and both low O(2) and high TEM together increased RA in shank weight. 5. These results suggest that late incubation conditions affect long bone development in broilers.

Discrepancies Between Plastic Surgery Meeting Abstracts and Subsequent Full-Length Manuscript Publications.

PubMed

Denadai, Rafael; Araujo, Gustavo Henrique; Pinho, Andre Silveira; Denadai, Rodrigo; Samartine, Hugo; Raposo-Amaral, Cassio Eduardo

2016-10-01

The purpose of this bibliometric study was to assess the discrepancies between plastic surgery meeting abstracts and subsequent full-length manuscript publications. Abstracts presented at the Brazilian Congress of Plastic Surgery from 2010 to 2011 were compared with matching manuscript publications. Discrepancies between the abstract and the subsequent manuscript were categorized as major (changes in the purpose, methods, study design, sample size, statistical analysis, results, and conclusions) and minor (changes in the title and authorship) variations. The overall discrepancy rate was 96 %, with at least one major (76 %) and/or minor (96 %) variation. There were inconsistencies between the study title (56 %), authorship (92 %), purpose (6 %), methods (20 %), study design (36 %), sample size (51.2 %), statistical analysis (14 %), results (20 %), and conclusions (8 %) of manuscripts compared with their corresponding meeting abstracts. As changes occur before manuscript publication of plastic surgery meeting abstracts, caution should be exercised in referencing abstracts or altering surgical practices based on abstracts' content. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Association between breast feeding and growth: the Boyd-Orr cohort study.

PubMed

Martin, R M; Smith, G Davey; Mangtani, P; Frankel, S; Gunnell, D

2002-11-01

To investigate the association of breast feeding with height and body mass index in childhood and adulthood. Historical cohort study, based on long term follow up of the Carnegie (Boyd-Orr) survey of diet and health in pre-war Britain (1937-1939). Sixteen urban and rural districts in Britain. A total of 4999 children from 1352 families were surveyed in 1937-1939. Information on infant feeding and childhood anthropometry was available for 2995 subjects. Mean differences in childhood and adult anthropometry between breast and bottle fed subjects. Breast feeding was associated with the survey district, greater household income, and food expenditure, but not with number of children in the household, birth order, or social class. In childhood, breast fed subjects were significantly taller than bottle fed subjects after controlling for socioeconomic variables. The mean height difference among boys was 0.20 standard deviation (SD) (95% confidence interval (CI) 0.07 to 0.32), and among girls it was 0.14 SD (95% CI 0.02 to 0.27). Leg length, but not trunk length, was the component of height associated with breast feeding. In males, breast feeding was associated with greater adult height (difference: 0.34 SD, 95% CI 0.13 to 0.55); of the two components of height, leg length (0.26 SD, 95% CI 0.02 to 0.50) was more strongly related to breast feeding than trunk length (0.16 SD, 95% CI -0.04 to 0.35). Height and leg length differences were in the same direction but smaller among adult females. There was no association between breast feeding and body mass index in childhood or adulthood. Compared with bottle fed infants, infants breast fed in the 1920s and 1930s were taller in childhood and adulthood. As stature is associated with health and life expectancy, the possible long term impact of infant feeding on adult mortality patterns merits further investigation.

Trans-tibial amputee gait: time-distance parameters and EMG activity.

PubMed

Isakov, E; Keren, O; Benjuya, N

2000-12-01

Gait analysis of trans-tibial (TT) amputees discloses asymmetries in gait parameters between the amputated and sound legs. The present study aimed at outlining differences between both legs with regard to kinematic parameters and activity of the muscles controlling the knees. The gait of 14 traumatic TT amputees, walking at a mean speed of 74.96 m/min, was analysed by means of an electronic walkway, video camera, and portable electromyography system. Results showed differences in kinematic parameters. Step length, step time and swing time were significantly longer, while stance time and single support time were significantly shorter on the amputated side. A significant difference was also found between knee angle in both legs at heel strike. The biceps femoris/vastus medialis ratio in the amputated leg, during the first half of stance phase, was significantly higher when compared to the same muscle ratio in the sound leg. This difference was due to the higher activity of the biceps femoris, almost four times higher than the vastus medialis in the amputated leg. The observed differences in time-distance parameters are due to stiffness of the prosthesis ankle (the SACH foot) that impedes the normal forward advance of the amputated leg during the first half of stance. The higher knee flexion at heel strike is due to the necessary socket alignment. Unlike in the sound leg, the biceps femoris in the amputated leg reaches maximal activity during the first half of stance, cocontracting with the vastus medialis, to support body weight on the amputated leg. The obtained data can serve as a future reference for evaluating the influence of new prosthetic components on the quality of TT amputee's gait.

Centre of pressure correlates with pyramid performance in acrobatic gymnastics.

PubMed

Floría, Pablo; Gómez-Landero, Luis Arturo; Harrison, Andrew J

2015-01-01

Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance.

What to measure when determining orthotic needs in children with Down syndrome: a pilot study.

PubMed

Looper, Julia; Benjamin, Danielle; Nolan, Mindy; Schumm, Laura

2012-01-01

To compare the effects of off-the-shelf foot orthoses and supramalleolar orthoses on the gait of children with Down syndrome (DS), and establish criteria for determining orthoses prescription for a child with DS. We assessed the gait of 6 children (aged 4-7 years) with DS using the GAITRite system, and obtained height, weight, leg length, hypermobility, calcaneal eversion, navicular drop, and tibial torsion measurements. Supramalleolar orthoses lead to a longer cycle time than foot orthoses (P = .05) and barefoot walking (P = .03) and a lower cadence than barefoot walking (P = .04). Significant strong correlations with gait parameters were obtained for height, leg length, and hypermobility. Biomechanical measurements showed no significant correlations with gait parameters. The role of physical examination data, including anthropometric and biomechanical measurements in the prescription of orthoses requires further investigation.

Influence of anthropometry on race performance in extreme endurance triathletes: World Challenge Deca Iron Triathlon 2006

PubMed Central

Knechtle, Beat; Knechtle, Patrizia; Andonie, Jorge Luis; Kohler, Götz

2007-01-01

Objective To investigate the influence of anthropometric variables on race performance in ultra‐endurance triathletes in an ultra‐triathlon. Design Descriptive field study. Setting The “World Challenge Deca Iron Triathlon 2006” in Monterrey, Mexico, in which everyday for 10 consecutive days athletes had to perform the distance of one Ironman triathlon of 3.8 km swimming, 180 km cycling and 42.195 km running. Subjects Eight male ultra‐endurance athletes (mean (SD) age 40.6 (10.7) years, weight 76.4 (8.4) kg, height 175 (4) cm and body mass index (BMI) 24.7 (2.2) kg/m2). Interventions None. Main outcome measures Direct measurement of body mass, height, leg length, skinfold thicknesses, limb circumference and calculation of BMI, skeletal muscle mass (SM), percentage SM (%SM) and percentage body fat (%BF) in order to correlate measured and calculated anthropometric variables with race performance. Results Race time was not significantly (p>0.05) influenced by the directly measured variables, height, leg length, body mass, average skinfold thicknesses, or circumference of thigh, calf or upper arm. Furthermore, no significant (p>0.05) correlation was observed between race time and the calculated variables, BMI, %SM and %BF. Conclusions In a multistage ultra‐triathlon over 10 Ironman triathlon distances in 10 consecutive days, there was no effect of body mass, height, leg length, skinfold thicknesses, limb circumference, BMI, %SM or %BF on race performance in the only eight finishers. PMID:17556527

The Effect of Hemispatial Neglect on the Perception of Centre

ERIC Educational Resources Information Center

Olk, Bettina; Wee, Joy; Kingstone, Alan

2004-01-01

Highly variable bisection performance in neglect patients has been attributed to an increased "zone of indifference" (Marshall & Halligan, 1989). The indifference zone indicates the discrepancy between two line lengths which are judged as equal in length. Following this argumentation, the central area of a line should be expanded in neglect…

A surgical protocol of ankle arthrodesis with combined Ilizarov's distraction-compression osteogenesis and locked nailing for osteomyelitis around the ankle joint.

PubMed

Chen, Chuan-Mu; Su, Alvin W; Chiu, Fang-Yao; Chen, Tain-Hsiung

2010-09-01

Managing refractory osteomyelitis around the ankle joint has been challenging. Destruction of both the ankle and the subtalar joints was common in cases of open fracture. For those who already had multiple surgeries, it would be tough to salvage the limb. Our goal was to set up a staged surgical protocol aiming in treating the aforementioned clinical issue. Twelve male patients underwent our protocol since year 2000. All patients presented refractory osteomyelitis, ankle and subtalar joint destruction, and poor soft tissue condition. All cases had internal fixation for open fractures followed by multiple debridement surgery before. The mean age was 50.8 years (range, 37-71 years), and the median follow-up time was 61 months (range, 48-96 months). The surgical protocol consisted of radical debridement, distraction osteogenesis for segmental bone transport, and tibia lengthening to avoid leg length discrepancy followed by intramedullary nailing for tibio-talo-calcaneal arthrodesis. The external fixation period averaged 24.7 weeks (range, 12-36 weeks). The mean duration to solid union of the arthrodesis and the bridging callus was 18.3 weeks (range, 16-20 weeks). Mild surgical site infection occurred in four cases but all subsided after removal of the nail and oral antibiotics use. At latest follow-up, all patients were infection free and could walk with plantigrade feet. The mean American Orthopaedic Foot and Ankle Society hindfoot score rising from 21.5 points (range 20-24 points) preoperatively to 65.5 points (range, 60-72). This study has shown our staged surgical protocol may be effective in solving complicated osteomyelitis around the ankle, although salvaging the limb with successful ankle arthrodesis and minimized limb length inequality, yet improving the patients' ambulation level.

Paediatric tibial shaft fractures treated by open reduction and stabilization with monolateral external fixation

PubMed Central

Simon, A.-L.; Apostolou, N.; Vidal, C.; Ferrero, E.; Mazda, K.; Ilharreborde, B.

2018-01-01

Abstract Purpose Elastic stable intramedullary nailing is increasingly used for surgical treatment of tibial shaft fractures, but frequently requires immobilization and delayed full weight-bearing. Therefore, external fixation remains interesting. The aim was to report clinico-radiological outcomes of monolateral external fixation for displaced and unstable tibial shaft fractures in children. Methods All tibial fractures consecutively treated by monolateral external fixation between 2008 and 2013 were followed. Inclusion criteria included skeletal immaturity and closed and open Gustilo I fractures caused by a direct impact. Patients were seen until two years postoperatively. Demographics, mechanism of injury, surgical data and complications were recorded. Anteroposterior and lateral side radiographs were performed at each visit. Full-limb 3D reconstructions using biplanar stereroradiography was performed for final limb length and alignment measures. Results A total of 45 patients (mean age 9.7 years ± 0.5) were included. In all, 17 were Gustilo I fractures, with no difference between open and closed fractures for any data. Mean time to full weight bearing was 18.2 days ± 0.7. After 15 days, 39 patients returned to school. Hardware removal (mean time to union 15.6 weeks ± 0.8) was performed during consultation under analgesic gas. There were no cases of nonunion. No fracture healed with > 10° of angulation (mean 5.1° ± 0.4°). Leg-length discrepancy > 10 mm was found for six patients. Conclusions This procedure can be a safe and simple surgical treatment for children with tibial shaft fractures. Few complications and early return to school were reported, with the limitations of non-comparative study. Level of Evidence IV PMID:29456750

Clinical Results and Complications of Lower Limb Lengthening for Fibular Hemimelia: A Report of Eight Cases.

PubMed

Mishima, Kenichi; Kitoh, Hiroshi; Iwata, Koji; Matsushita, Masaki; Nishida, Yoshihiro; Hattori, Tadashi; Ishiguro, Naoki

2016-05-01

Fibular hemimelia is a rare but the most common congenital long bone deficiency, encompassing a broad range of anomalies from isolated fibular hypoplasia up to substantial femoral and tibial shortening with ankle deformity and foot deficiency. Most cases of fibular hemimelia manifest clinically significant leg length discrepancy (LLD) with time that requires adequate correction by bone lengthening for stable walking. Bone lengthening procedures, especially those for pathological bones, are sometimes associated with severe complications, such as delayed consolidation, fractures, and deformities of the lengthened bones, leading to prolonged healing time and residual LLD at skeletal maturity. The purpose of this study was to review our clinical results of lower limb lengthening for fibular hemimelia.This study included 8 Japanese patients who diagnosed with fibular hemimelia from physical and radiological findings characteristic of fibular hemimelia and underwent single or staged femoral and/or tibial lengthening during growth or after skeletal maturity. LLD, state of the lengthened callus, and bone alignment were evaluated with full-length radiographs of the lower limb. Previous interventions, associated congenital anomalies, regenerate fractures were recorded with reference to medical charts and confirmed on appropriate radiographs. Successful lengthening was defined as the healing index <50 days/cm without regenerate fractures.A significant difference was observed in age at surgery between successful and unsuccessful lengthening. The incidence of regenerate fractures was significantly correlated with callus maturity before frame removal. LLD was corrected within 11 mm, whereas mechanical axis deviated laterally.Particular attention should be paid to the status of callus maturation and the mechanical axis deviation during the treatment period in fibular hemimelia.

Shape adjustment optimization and experiment of cable-membrane reflectors

NASA Astrophysics Data System (ADS)

Du, Jingli; Gu, Yongzhen; Bao, Hong; Wang, Congsi; Chen, Xiaofeng

2018-05-01

Cable-membrane structures are widely employed for large space reflectors due to their lightweight, compact and easy package. In these structures, membranes are attached to cable net, serving as reflectors themselves or as supporting structures for other reflective surface. The cable length and membrane shape have to be carefully designed and fabricated to guarantee the desired reflector surface shape. However, due to inevitable error in cable length and membrane shape during the manufacture and assembly of cable-membrane reflectors, some cables have to be designed to be capable of length adjustment. By carefully adjusting the length of these cables, the degeneration in reflector shape precision due to this inevitable error can be effectively reduced. In the paper a shape adjustment algorithm for cable-membrane reflectors is proposed. Meanwhile, model updating is employed during shape adjustment to decrease the discrepancy of the numerical model with respect to the actual reflector. This discrepancy has to be considered because during attaching membranes to cable net, the accuracy of the membrane shape is hard to guarantee. Numerical examples and experimental results demonstrate the proposed method.

Running springs: speed and animal size.

PubMed

Farley, C T; Glasheen, J; McMahon, T A

1993-12-01

Trotting and hopping animals use muscles, tendons and ligaments to store and return elastic energy as they bounce along the ground. We examine how the musculoskeletal spring system operates at different speeds and in animals of different sizes. We model trotting and hopping as a simple spring-mass system which consists of a leg spring and a mass. We find that the stiffness of the leg spring (k(leg)) is nearly independent of speed in dogs, goats, horses and red kangaroos. As these animals trot or hop faster, the leg spring sweeps a greater angle during the stance phase, and the vertical excursion of the center of mass during the ground contact phase decreases. The combination of these changes to the spring system causes animals to bounce off the ground more quickly at higher speeds. Analysis of a wide size range of animals (0.1-140 kg) at equivalent speeds reveals that larger animals have stiffer leg springs (k(leg) [symbol: see text] M0.67, where M is body mass), but that the angle swept by the leg spring is nearly independent of body mass. As a result, the resonant period of vertical vibration of the spring-mass system is longer in larger animals. The length of time that the feet are in contact with the ground increases with body mass in nearly the same way as the resonant period of vertical vibration.

Effect of unilateral knee extensor fatigue on force and balance of the contralateral limb.

PubMed

Arora, Shruti; Budden, Shawn; Byrne, Jeannette M; Behm, David G

2015-10-01

Fatigue in one limb can decrease force production in the homologous muscle as well as other muscles of the non-fatigued limb affecting balance. The objective of the study was to examine the effect of unilateral knee extensor fatigue on the non-fatigued limb's standing balance, muscle force and activation. Sixteen healthy male subjects performed pre-fatigue balance trials, warm-up exercises, maximum voluntary isometric contractions, a knee extensors fatigue protocol, and post-fatigue balance trials. The fatigue protocol consisted of sets of 15 consecutive isometric contractions of 16 s each with 4 s recovery between repetitions, which were performed at 30% peak force for the dominant knee extensor muscles. Additional sets of contractions continued until a 50% decrease in MVIC knee extensor force was observed. Pre- and post-fatigue balance assessment consisted of transition from double to single leg standing and also single leg standing trials, which were performed bilaterally and in randomized order. The peak force and F100 were significantly decreased by 44.8% (ES = 2.54) and 39.9% (ES = 0.59), respectively, for the fatigued limb post-fatigue. There were no significant changes in the non-fatigued limb's muscle force, activation, muscle onset timing or postural stability parameters. While the lack of change in non-fatigued limb force production is in agreement with some of the previous literature in this area, the lack of effect on postural measures directly contradicts earlier work. It is hypothesized that discrepancies in the duration and the intensity of the fatigue protocol may have accounted for this discrepancy.

Experimental and numerical analysis of clamped joints in front motorbike suspensions

NASA Astrophysics Data System (ADS)

Croccolo, D.; de Agostinis, M.; Vincenzi, N.

2010-06-01

Clamped joints are shaft-hub connections used, as an instance, in front motorbike suspensions to lock the steering plates with the legs and the legs with the wheel pin, by means of one or two bolts. The preloading force, produced during the tightening process, should be evaluated accurately, since it must lock safely the shaft, without overcoming the yielding point of the hub. Firstly, friction coefficients have been evaluated on “ad-hoc designed” specimens, by applying the Design of Experiment approach: the applied tightening torque has been precisely related to the imposed preloading force. Then, the tensile state of clamps have been evaluated both via FEM and by leveraging some design formulae proposed by the Authors as function of the preloading force and of the clamp geometry. Finally, the results have been compared to those given by some strain gauges applied on the tested clamps: the discrepancies between numerical analyses, the design formulae and the experimental results remains under a threshold of 10%.

Influence of Age, Maturity, and Body Size on the Spatiotemporal Determinants of Maximal Sprint Speed in Boys.

PubMed

Meyers, Robert W; Oliver, Jon L; Hughes, Michael G; Lloyd, Rhodri S; Cronin, John B

2017-04-01

Meyers, RW, Oliver, JL, Hughes, MG, Lloyd, RS, and Cronin, JB. Influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. J Strength Cond Res 31(4): 1009-1016, 2017-The aim of this study was to investigate the influence of age, maturity, and body size on the spatiotemporal determinants of maximal sprint speed in boys. Three-hundred and seventy-five boys (age: 13.0 ± 1.3 years) completed a 30-m sprint test, during which maximal speed, step length, step frequency, contact time, and flight time were recorded using an optical measurement system. Body mass, height, leg length, and a maturity offset represented somatic variables. Step frequency accounted for the highest proportion of variance in speed (∼58%) in the pre-peak height velocity (pre-PHV) group, whereas step length explained the majority of the variance in speed (∼54%) in the post-PHV group. In the pre-PHV group, mass was negatively related to speed, step length, step frequency, and contact time; however, measures of stature had a positive influence on speed and step length yet a negative influence on step frequency. Speed and step length were also negatively influence by mass in the post-PHV group, whereas leg length continued to positively influence step length. The results highlighted that pre-PHV boys may be deemed step frequency reliant, whereas those post-PHV boys may be marginally step length reliant. Furthermore, the negative influence of body mass, both pre-PHV and post-PHV, suggests that training to optimize sprint performance in youth should include methods such as plyometric and strength training, where a high neuromuscular focus and the development force production relative to body weight are key foci.

Accuracy of self-reported length of coma and posttraumatic amnesia in persons with medically verified traumatic brain injury.

PubMed

Sherer, Mark; Sander, Angelle M; Maestas, Kacey Little; Pastorek, Nicholas J; Nick, Todd G; Li, Jingyun

2015-04-01

To determine the accuracy of self-reported length of coma and posttraumatic amnesia (PTA) in persons with medically verified traumatic brain injury (TBI) and to investigate factors that affect self-report of length of coma and PTA duration. Prospective cohort study. Specialized rehabilitation center with inpatient and outpatient programs. Persons (N=242) with medically verified TBI who were identified from a registry of persons who had previously participated in TBI-related research. Not applicable. Self-reported length of coma and self-reported PTA duration. Review of medical records revealed that the mean medically documented length of coma and PTA duration was 6.9±12 and 19.2±22 days, respectively, and the mean self-reported length of coma and PTA duration was 16.7±22 and 106±194 days, respectively. The average discrepancy between self-report and medical record for length of coma and PTA duration was 8.2±21 and 64±176 days, respectively. Multivariable regression models revealed that time since injury, performance on cognitive tests, and medical record values were associated with self-reported values for both length of coma and PTA duration. In this investigation, persons with medically verified TBI showed poor accuracy in their self-report of length of coma and PTA duration. Discrepancies were large enough to affect injury severity classification. Caution should be exercised when considering self-report of length of coma and PTA duration. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Froude number fractions to increase walking pattern dynamic similarities: application to plantar pressure study in healthy subjects.

PubMed

Moretto, P; Bisiaux, M; Lafortune, M A

2007-01-01

The purpose of this study was to determine if using similar walking velocities obtained from fractions of the Froude number (N(Fr)) and leg length can lead to kinematic and kinetic similarities and lower variability. Fifteen male subjects walked on a treadmill at 0.83 (VS(1)) and 1.16ms(-1) (VS(2)) and then at two similar velocities (V(Sim27) and V(Sim37)) determined from two fractions of the N(Fr) (0.27 and 0.37) so that the average group velocity remained unchanged in both conditions (VS(1)=V (Sim27)andVS(2)=V (Sim37)). N(Fr) can theoretically be used to determine walking velocities proportional to leg lengths and to establish dynamic similarities between subjects. This study represents the first attempt at using this approach to examine plantar pressure. The ankle and knee joint angles were studied in the sagittal plane and the plantar pressure distribution was assessed with an in-shoe measurement device. The similarity ratios were computed from anthropometric parameters and plantar pressure peaks. Dynamically similar conditions caused a 25% reduction in leg joint angles variation and a 10% significant decrease in dimensionless pressure peak variability on average of five footprint locations. It also lead to heel and under-midfoot pressure peaks proportional to body mass and to an increase in the number of under-forefoot plantar pressure peaks proportional to body mass and/or leg length. The use of walking velocities derived from N(Fr) allows kinematic and plantar pressure similarities between subjects to be observed and leads to a lower inter-subject variability. In-shoe pressure measurements have proven to be valuable for the understanding of lower extremity function. Set walking velocities used for clinical assessment mask the effects of body size and individual gait mechanics. The anthropometric scaling of walking velocities (fraction of N(Fr)) should improve identification of unique walking strategies and pathological foot functions.

Identification and Comparative Study of Chemosensory Genes Related to Host Selection by Legs Transcriptome Analysis in the Tea Geometrid Ectropis obliqua

PubMed Central

Bian, Lei; Cai, Xiao-Ming; Luo, Zong-Xiu; Zhang, Yong-Jun; Chen, Zong-Mao

2016-01-01

Host selection by female moths is fundamental to the survival of their larvae. Detecting and perceiving the non-volatile chemicals of the plant surface involved in gustatory detection determine the host preference. In many lepidopteran species, tarsal chemosensilla are sensitive to non-volatile chemicals and responsible for taste detection. The tea geometrid Ectropis obliqua is one devastating chewing pest selectively feeding on limited plants, requiring the specialized sensors to forage certain host for oviposition. In present study, we revealed the distribution of chemosensilla in the ventral side of female fifth tarsomere in E. obliqua. To investigate its molecular mechanism of gustatory perception, we performed HiSeq 2500 sequencing of the male- and female- legs transcriptome and identified 24 candidate odorant binding proteins (OBPs), 21 chemosensory proteins (CSPs), 2 sensory neuron membrane proteins (SNMPs), 3 gustatory receptors (GRs) and 4 odorant receptors (ORs). Several leg-specific or enriched chemosensory genes were screened by tissue expression analysis, and clustered with functionally validated genes from other moths, suggesting the potential involvement in taste sensation or other physiological processes. The RPKM value analysis revealed that 9 EoblOBPs showed sex discrepancy in the leg expression, 8 being up-regulated in female and only 1 being over expressed in male. These female-biased EoblOBPs indicated an ecological adaption related with host-seeking and oviposition behaviors. Our work will provide basic knowledge for further studies on the molecular mechanism of gustatory perception, and enlighten a host-selection-based control strategy of insect pests. PMID:26930056

The p({gamma}, {pi}{sup 0}) reaction in the {Delta}(1232) region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, R.M.; Gutenberg, J.; Mukhopadhyay, N.C.

Linearly polarized photons from the Laser Electron Gamma Source (LEGS) have been used by Blanpied et al. to study the p({gamma}, {pi}{sup 0}) reaction, looking for the E2 transition amplitude in the nucleon to Delta(1232) excitation. These authors contrast their measured cross-section ratio d{sigma}{parallel}/d{sigma}{perpendicular}, with expectations of earlier analyses, by the authors and Wittman (DMW), by Nozawa et al. (NBL), and using the multipoles of Behrends and Donnachie directly, and find {open_quotes}large discrepancies{close_quotes} among them. Here the authors clarify these discrepancies. The crucial difference between DMW and NBL calculations is the inclusion of the u-channel {Delta} contribution in DMW, omittedmore » in NBL. The authors find for a fair, though not perfect, agreement with the new data: E{sub 1+}{sup {pi}}{sup 0} {r_arrow}2.1E{sub 1+}{sup {pi}}{sup 0}, keeping other multipoles fixed.« less

Discrepancies in reporting the CAG repeat lengths for Huntington's disease

PubMed Central

Quarrell, Oliver W; Handley, Olivia; O'Donovan, Kirsty; Dumoulin, Christine; Ramos-Arroyo, Maria; Biunno, Ida; Bauer, Peter; Kline, Margaret; Landwehrmeyer, G Bernhard

2012-01-01

Huntington's disease results from a CAG repeat expansion within the Huntingtin gene; this is measured routinely in diagnostic laboratories. The European Huntington's Disease Network REGISTRY project centrally measures CAG repeat lengths on fresh samples; these were compared with the original results from 121 laboratories across 15 countries. We report on 1326 duplicate results; a discrepancy in reporting the upper allele occurred in 51% of cases, this reduced to 13.3% and 9.7% when we applied acceptable measurement errors proposed by the American College of Medical Genetics and the Draft European Best Practice Guidelines, respectively. Duplicate results were available for 1250 lower alleles; discrepancies occurred in 40% of cases. Clinically significant discrepancies occurred in 4.0% of cases with a potential unexplained misdiagnosis rate of 0.3%. There was considerable variation in the discrepancy rate among 10 of the countries participating in this study. Out of 1326 samples, 348 were re-analysed by an accredited diagnostic laboratory, based in Germany, with concordance rates of 93% and 94% for the upper and lower alleles, respectively. This became 100% if the acceptable measurement errors were applied. The central laboratory correctly reported allele sizes for six standard reference samples, blind to the known result. Our study differs from external quality assessment (EQA) schemes in that these are duplicate results obtained from a large sample of patients across the whole diagnostic range. We strongly recommend that laboratories state an error rate for their measurement on the report, participate in EQA schemes and use reference materials regularly to adjust their own internal standards. PMID:21811303

The Relationship of Explicit-Implicit Evaluative Discrepancy to Exercise Dropout in Middle-Aged Adults.

PubMed

Berry, Tanya R; Rodgers, Wendy M; Divine, Alison; Hall, Craig

2018-06-19

Discrepancies between automatically activated associations (i.e., implicit evaluations) and explicit evaluations of motives (measured with a questionnaire) could lead to greater information processing to resolve discrepancies or self-regulatory failures that may affect behavior. This research examined the relationship of health and appearance exercise-related explicit-implicit evaluative discrepancies, the interaction between implicit and explicit evaluations, and the combined value of explicit and implicit evaluations (i.e., the summed scores) to dropout from a yearlong exercise program. Participants (N = 253) completed implicit health and appearance measures and explicit health and appearance motives at baseline, prior to starting the exercise program. The sum of implicit and explicit appearance measures was positively related to weeks in the program, and discrepancy between the implicit and explicit health measures was negatively related to length of time in the program. Implicit exercise evaluations and their relationships to oft-cited motives such as appearance and health may inform exercise dropout.

Final Report - Few-Body Studies Using Electromagnetic Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norum, Blaine

The work discussed here is an extension of work previously funded by U.S. Department of Energy Grant DE-FG02-97ER41025. Measurements of charged pion photoproduction from deuterium using the Laser Electron Gamma Source (LEGS) at the Brookhaven National Laboratory previously made by us, as members of the LEGS Collaboration, resulted in the most interesting result of two decades of work. By measuring the production of a charged pion (π +) in coincidence with an emitted photon we observed structures in the residual two-nucleon system. These indicated the existence of rare, long-lived states not explicable by standard nuclear theory; they suggested a setmore » of configurations not explicable in terms of a nucleon-nucleon pair. The existence of such “exotic” structures has formed the foundation for most of the work that has ensued. Several measurements at various laboratories have supported, but not proved, the existence of these exotic states. The rarity of these states made their existence undetectable in most previous measurements. Only by observing characteristic signatures of such states (i.e., decay photons), by using very specific kinematics which isolate certain reaction products, or by measuring polarization-dependent observables. During the period of this grant we pursued and made progress on the development of experiments to be performed at the High Intensity Gamma Source (HIGS) of the Tri Universities Nuclear Laboratory (TUNL). Our understanding of photon- and electron-induced nuclear reactions depends on understanding of the basic electron and photon interaction. Recently, the issue of two-photon contributions has arisen in the context of deeply inelastic electron scattering. One way to address this is to measure asymmetries in the Bethe-Heitler ee process. We also made progress in developing the detectors required to measure these asymmetries at HIGS. During the last several years the apparent discrepancy between the size of the proton as measured using electrons and that as measured using muons has received a great deal of attention. Working with colleagues at the Jefferson Laboratory (JLAB) we showed that the apparent discrepancy was almost surely the result of mistakes in the statistical analysis of electron scattering data, that there is almost surely no discrepancy.« less

The specific scintigraphic pattern of "shin splints in the lower leg": concise communication.

PubMed

Holder, L E; Michael, R H

1984-08-01

The clinical entity, "shin splints," is now being recognized, and more specifically characterized by the findings of exercise-induced pain and tenderness to palpation along the posterior medial border of the tibia. In this prospective study, ten patients with this syndrome were evaluated using three-phase bone scintigrams, and a specific scintigraphic pattern was determined. Radionuclide angiograms and blood-pool images were all normal. On delayed images, tibial lesions involved the posterior cortex, were longitudinally oriented, were long, involving one third of the length of the bone, and often showed varying tracer uptake along that length. Obtaining both lateral and medial views was crucial. The location of activity suggested that this entity is related to the soleus muscle. These scintigraphic findings can be used to differentiate shin splints from stress fractures or other conditions causing pain in the lower leg in athletes.

Birds achieve high robustness in uneven terrain through active control of landing conditions.

PubMed

Birn-Jeffery, Aleksandra V; Daley, Monica A

2012-06-15

We understand little about how animals adjust locomotor behaviour to negotiate uneven terrain. The mechanical demands and constraints of such behaviours likely differ from uniform terrain locomotion. Here we investigated how common pheasants negotiate visible obstacles with heights from 10 to 50% of leg length. Our goal was to determine the neuro-mechanical strategies used to achieve robust stability, and address whether strategies vary with obstacle height. We found that control of landing conditions was crucial for minimising fluctuations in stance leg loading and work in uneven terrain. Variation in touchdown leg angle (θ(TD)) was correlated with the orientation of ground force during stance, and the angle between the leg and body velocity vector at touchdown (β(TD)) was correlated with net limb work. Pheasants actively targeted obstacles to control body velocity and leg posture at touchdown to achieve nearly steady dynamics on the obstacle step. In the approach step to an obstacle, the birds produced net positive limb work to launch themselves upward. On the obstacle, body dynamics were similar to uniform terrain. Pheasants also increased swing leg retraction velocity during obstacle negotiation, which we suggest is an active strategy to minimise fluctuations in peak force and leg posture in uneven terrain. Thus, pheasants appear to achieve robustly stable locomotion through a combination of path planning using visual feedback and active adjustment of leg swing dynamics to control landing conditions. We suggest that strategies for robust stability are context specific, depending on the quality of sensory feedback available, especially visual input.

Robust passive dynamics of the musculoskeletal system compensate for unexpected surface changes during human hopping

PubMed Central

van der Krogt, Marjolein M.; de Graaf, Wendy W.; Farley, Claire T.; Moritz, Chet T.; Richard Casius, L. J.; Bobbert, Maarten F.

2009-01-01

When human hoppers are surprised by a change in surface stiffness, they adapt almost instantly by changing leg stiffness, implying that neural feedback is not necessary. The goal of this simulation study was first to investigate whether leg stiffness can change without neural control adjustment when landing on an unexpected hard or unexpected compliant (soft) surface, and second to determine what underlying mechanisms are responsible for this change in leg stiffness. The muscle stimulation pattern of a forward dynamic musculoskeletal model was optimized to make the model match experimental hopping kinematics on hard and soft surfaces. Next, only surface stiffness was changed to determine how the mechanical interaction of the musculoskeletal model with the unexpected surface affected leg stiffness. It was found that leg stiffness adapted passively to both unexpected surfaces. On the unexpected hard surface, leg stiffness was lower than on the soft surface, resulting in close-to-normal center of mass displacement. This reduction in leg stiffness was a result of reduced joint stiffness caused by lower effective muscle stiffness. Faster flexion of the joints due to the interaction with the hard surface led to larger changes in muscle length, while the prescribed increase in active state and resulting muscle force remained nearly constant in time. Opposite effects were found on the unexpected soft surface, demonstrating the bidirectional stabilizing properties of passive dynamics. These passive adaptations to unexpected surfaces may be critical when negotiating disturbances during locomotion across variable terrain. PMID:19589956

Changes in leg spring behaviour, plantar loading and foot mobility magnitude induced by an exhaustive treadmill run in adolescent middle-distance runners.

PubMed

Fourchet, François; Girard, Olivier; Kelly, Luke; Horobeanu, Cosmin; Millet, Grégoire P

2015-03-01

This study aimed to determine adjustments in spring-mass model characteristics, plantar loading and foot mobility induced by an exhaustive run. Within-participants repeated measures. Eleven highly-trained adolescent middle-distance runners ran to exhaustion on a treadmill at a constant velocity corresponding to 95% of velocity associated with VO₂max (17.8 ± 1.4 kmh(-1), time to exhaustion=8.8 ± 3.4 min). Contact time obtained from plantar pressure sensors was used to estimate spring-mass model characteristics, which were recorded (during 30 s) 1 min after the start and prior to exhaustion using pressure insoles. Foot mobility magnitude (a composite measure of vertical and medial-lateral mobility of the midfoot) was measured before and after the run. Mean contact area (foot to ground), contact time, peak vertical ground reaction force, centre of mass vertical displacement and leg compression increased significantly with fatigue, while flight time, leg stiffness and mean pressure decreased. Leg stiffness decreased because leg compression increased to a larger extent than peak vertical ground reaction forces. Step length, step frequency and foot mobility magnitude did not change at exhaustion. The stride pattern of adolescents when running on a treadmill at high constant velocity deteriorates near exhaustion, as evidenced by impaired leg-spring behaviour (leg stiffness) and altered plantar loading. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

An allometric analysis of the number of muscle spindles in mammalian skeletal muscles

PubMed Central

Banks, R W

2006-01-01

An allometric analysis of the number of muscle spindles in relation to muscle mass in mammalian (mouse, rat, guinea-pig, cat, human) skeletal muscles is presented. It is shown that the trend to increasing number as muscle mass increases follows an isometric (length) relationship between species, whereas within a species, at least for the only essentially complete sample (human), the number of spindles scales, on average, with the square root rather than the cube root of muscle mass. An attempt is made to reconcile these apparently discrepant relationships. Use of the widely accepted spindle density (number of spindles g−1 of muscle) as a measure of relative abundance of spindles in different muscles is shown to be grossly misleading. It is replaced with the residuals of the linear regression of ln spindle number against ln muscle mass. Significant differences in relative spindle abundance as measured by residuals were found between regional groups of muscles: the greatest abundance is in axial muscles, including those concerned with head position, whereas the least is in muscles of the shoulder girdle. No differences were found between large and small muscles operating in parallel, or between antigravity and non-antigravity muscles. For proximal vs. distal muscles, spindles were significantly less abundant in the hand than the arm, but there was no difference between the foot and the leg. PMID:16761976

Shelf Acetabuloplasty in the Treatment of Severe Legg-Calvé-Perthes Disease: Good Outcomes at Midterm Follow-Up

PubMed Central

Grzegorzewski, Andrzej; Synder, Marek; Kmieć, Krysztof; Krajewski, Karol; Polguj, Michał; Sibiński, Marcin

2013-01-01

The aim of the study was to retrospectively review results of operative treatment for coverage deficit of femoral head in children with severe epiphysis displacement in Legg-Calvé-Perthes (LCP) disease. The material included 23 shelf acetabuloplasty procedures for LCP disease. The average age at diagnosis was 8.1 years (range 4–12). Mean follow-up was 5.8 years (range from 2.2 to 11.2 years). Mean Reimer's index decreased statistically significantly from a mean of 32% before surgery to 10.0% at the last follow-up (P < 0.00001). The mean Wiberg center-edge angle increased also statistically significantly from a mean of 17.3° before procedure to 32.3° at the last follow-up (P < 0.00001). According to the Stulberg classification, type I was observed in 2, type II in 13, type III in 6, and type IV in 2 hips. There were no differences in the range of motion or leg length discrepancy in preoperative and postoperative standing. Partial, not significant, bone graft resorption was noted in 6 cases in the first 6–9 months after surgery. To conclude, shelf acetabuloplasty allows achieving good midterm results in the treatment of severe stages of LCP disease. The procedure improves coverage of femoral head and allows its remodelling. PMID:24377097

Arthrodesis in septic knees using a long intramedullary nail: 17 consecutive cases.

PubMed

Leroux, B; Aparicio, G; Fontanin, N; Ohl, X; Madi, K; Dehoux, E; Diallo, S

2013-06-01

Intramedullary nailing using long or modular nails is the most reliable mean of achieving femorotibial fusion. Here, we report the operative, clinical, functional, and radiological outcomes of 17 long intramedullary nail arthodeses in patients with infection. Clinical and functional outcomes after long intramedullary nailing are at least as good as those obtained using other implants. We retrospectively reevaluated 17 patients after unilateral two-stage knee arthrodesis with a long titanium intramedullary nail and autologous bone grafting. We evaluated satisfaction, leg length discrepancy, and function (Lequesne and WOMAC indices). Radiographs were obtained to assess fusion, time to fusion, and femorotibial angles. No cases of material failure were recorded. One or more complications occurred in seven patients. Mean limb shortening was 27.6mm. Of the 17 patients, 15 were satisfied with the procedure. The mean Lequesne index was 10.5/24 and the mean overall WOMAC score was 26/88. Fusion was achieved in 16 patients, with a mean time to fusion of 5 months. Mean femorotibial angles were 178.6° of varus and 1.9° of flexion. This simple and rapid surgical technique provides functional outcomes similar to those obtained using modular nails. The fusion rate is high. Nail extraction is simple and causes minimal damage, in contrast to modular nails. Increased attention to misalignment is needed. Level IV, retrospective study. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Sport injuries: a review of outcomes.

PubMed

Maffulli, Nicola; Longo, Umile Giuseppe; Gougoulias, Nikolaos; Caine, Dennis; Denaro, Vincenzo

2011-01-01

Injuries can counter the beneficial aspects related to sports activities if an athlete is unable to continue to participate because of residual effects of injury. We provide an updated synthesis of existing clinical evidence of long-term follow-up outcome of sports injuries. A systematic computerized literature search was conducted on following databases were accessed: PubMed, Medline, Cochrane, CINAHL and Embase databases. At a young age, injury to the physis can result in limb deformities and leg-length discrepancy. Weight-bearing joints including the hip, knee and ankle are at risk of developing osteoarthritis (OA) in former athletes, after injury or in the presence of malalignment, especially in association with high impact sport. Knee injury is a risk factor for OA. Ankle ligament injuries in athletes result in incomplete recovery (up to 40% at 6 months), and OA in the long term (latency period more than 25 years). Spine pathologies are associated more commonly with certain sports (e.g. wrestling, heavy-weight lifting, gymnastics, tennis, soccer). Evolution in arthroscopy allows more accurate assessment of hip, ankle, shoulder, elbow and wrist intra-articular post-traumatic pathologies, and possibly more successful management. Few well-conducted studies are available to establish the long-term follow-up of former athletes. To assess whether benefits from sports participation outweigh the risks, future research should involve questionnaires regarding the health-related quality of life in former athletes, to be compared with the general population.

Fixator-assisted medial tibial plateau elevation to treat severe Blount's disease: outcomes at maturity.

PubMed

Fitoussi, F; Ilharreborde, B; Lefevre, Y; Souchet, P; Presedo, A; Mazda, K; Penneçot, G F

2011-04-01

Severe forms of Blount's disease may be associated with medial tibial plateau (MTP) depression. Management should then take account of joint congruence, laxity, limb axis, torsional abnomality, leg length discrepancy (LLD) and eventual recurrence history. Eight knees (six patients) were managed in a single step comprising MTP elevation osteotomy, lateral epiphysiodesis and proximal tibia osteotomy to correct varus and rotational deformity. Fixation was achieved using an Ilizarov external fixator. Mean age was 10.5 years. Mean hip-knee-ankle (HKA) angle was 151°; distal femoral varus, 94°; metaphyseal-diaphyseal angle (MDA), 27°; and angle of depression of the medial tibial plateau (ADMTP), 42°. Predicted residual proximal tibial growth was 2.6 cm. At a mean 48 months' follow-up, results were good in six cases, medium in one and poor (due to incomplete lateral epiphysiodesis) in one. Mean lateral tibial torsion was 9° and final LLD 11 mm. Weight-bearing was resumed at 2 months, and the fixator was removed at 5.5 months postoperatively. At end of follow-up, mean HKA angle was 179.6°, MDA 7.3° and ADMTP 5.4°. This technically demanding procedure gave satisfactory results in terms of axes and congruence; longer term assessment remains needed. Level IV. Retrospective study. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

In-series compliance of gastrocnemius muscle in cat step cycle: do spindles signal origin-to-insertion length?

PubMed Central

Elek, J; Prochazka, A; Hulliger, M; Vincent, S

1990-01-01

1. It has been claimed that stretch in the non-contractile (extramysial) portion of muscles is substantial, and may produce large discrepancies between the origin-to-insertion muscle length and the internal length variations 'seen' by muscle spindle endings. 2. In eight pentobarbitone-anaesthetized cats, we estimated stretch in the extramysial portion of medial gastrocnemius (MG) muscle with a method similar to the spindle null technique. 3. Length variations of MG previously monitored in a normal step cycle were reproduced with a computer-controlled length servo. The responses of test MG spindle endings were monitored in dorsal root filaments. Distributed stimulation of ventral root filaments, rate-modulated by the step-cycle EMG envelope, served to reproduce step-cycle forces. The filaments were selected so as to have no fusimotor action on the test spindle. 4. Spindle responses in active cycles were compared with those in passive cycles (stretch, but no distributed stimulation). In some cases concomitant tonic fusimotor stimulation was used to maintain spindle responsiveness throughout the cycle, both in active and passive trials. Generally, small discrepancies in spindle firing were seen. The passive trials were now repeated, with iterative adjustments of the length function, until the response matched the spindle firing profile in the active trial. The spindle 'saw' the same internal length change in the final passive trial as in the active trial. Any difference between the corresponding length profiles was attributed to extramysial displacement. 5. Extramysial displacement estimated in this was was maximal at short mean muscle lengths, reaching about 0.5 mm in a typical step cycle (force rising from 0 to 10 N). At longer mean muscle lengths where muscle force rose from say 2 to 12 N in the cycle, extramysial displacement was in the range 0.2-0.4 mm. 6. Except at very short lengths, the displacement was probably mainly tendinous. On this assumption, our results suggested that the stiffness of the MG tendinous compartment was force related, and about double that of cat soleus muscle at any given force. Calculations indicated that though the stretch was small, the MG tendon would store and release enough strain energy per cycle to contribute significantly to the E3 phase of the step cycle. The discrepancies in spindle firing were generally quite subtle, so we reject the claim that extramysial stretch poses a serious difficulty for inferences about fusimotion from chronic spindle afferent recordings. PMID:2148952

Is adult gait less susceptible than paediatric gait to hip joint centre regression equation error?

PubMed

Kiernan, D; Hosking, J; O'Brien, T

2016-03-01

Hip joint centre (HJC) regression equation error during paediatric gait has recently been shown to have clinical significance. In relation to adult gait, it has been inferred that comparable errors with children in absolute HJC position may in fact result in less significant kinematic and kinetic error. This study investigated the clinical agreement of three commonly used regression equation sets (Bell et al., Davis et al. and Orthotrak) for adult subjects against the equations of Harrington et al. The relationship between HJC position error and subject size was also investigated for the Davis et al. set. Full 3-dimensional gait analysis was performed on 12 healthy adult subjects with data for each set compared to Harrington et al. The Gait Profile Score, Gait Variable Score and GDI-kinetic were used to assess clinical significance while differences in HJC position between the Davis and Harrington sets were compared to leg length and subject height using regression analysis. A number of statistically significant differences were present in absolute HJC position. However, all sets fell below the clinically significant thresholds (GPS <1.6°, GDI-Kinetic <3.6 points). Linear regression revealed a statistically significant relationship for both increasing leg length and increasing subject height with decreasing error in anterior/posterior and superior/inferior directions. Results confirm a negligible clinical error for adult subjects suggesting that any of the examined sets could be used interchangeably. Decreasing error with both increasing leg length and increasing subject height suggests that the Davis set should be used cautiously on smaller subjects. Copyright © 2016 Elsevier B.V. All rights reserved.

Primordial Dwarfism

MedlinePlus

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The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia.

PubMed

Sims, David T; Onambélé-Pearson, Gladys L; Burden, Adrian; Payton, Carl; Morse, Christopher I

2018-01-01

The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption ([Formula: see text]O 2 ) and metabolic cost (C) when walking at running compared to those of average stature (controls). The aim of this study was to measure submaximal [Formula: see text]O 2 and C during a range of set walking speeds (SWS; 0.56 - 1.94 m⋅s -1 , increment 0.28 m⋅s -1 ), set running speeds (SRS; 1.67 - 3.33 m⋅s -1 , increment 0.28 m⋅s -1 ) and a self-selected walking speed (SSW). [Formula: see text]O 2 and C was scaled to total body mass (TBM) and fat free mass (FFM) while gait speed was scaled to leg length using Froude's number (Fr). Achondroplasic [Formula: see text]O 2TBM and [Formula: see text]O 2FFM were on average 29 and 35% greater during SWS ( P < 0.05) and 12 and 18% higher during SRS ( P < 0.05) than controls, respectively. Achondroplasic C TBM and C FFM were 29 and 33% greater during SWS ( P < 0.05) and 12 and 18% greater during SRS ( P < 0.05) than controls, respectively. There was no difference in SSW [Formula: see text]O 2TBM or [Formula: see text]O 2FFM between groups ( P > 0.05), but C TBM and C FFM at SSW were 23 and 29% higher ( P < 0.05) in the Achondroplasic group compared to controls, respectively. [Formula: see text]O 2TBM and [Formula: see text]O 2FFM correlated with Fr for both groups ( r = 0.984 - 0.999, P < 0.05). Leg length accounted for the majority of the higher [Formula: see text]O 2TBM and [Formula: see text]O 2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic C TBM and C FFM at all speeds compared to controls. New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups.

Asymmetry of short-term control of spatio-temporal gait parameters during treadmill walking

NASA Astrophysics Data System (ADS)

Kozlowska, Klaudia; Latka, Miroslaw; West, Bruce J.

2017-03-01

Optimization of energy cost determines average values of spatio-temporal gait parameters such as step duration, step length or step speed. However, during walking, humans need to adapt these parameters at every step to respond to exogenous and/or endogenic perturbations. While some neurological mechanisms that trigger these responses are known, our understanding of the fundamental principles governing step-by-step adaptation remains elusive. We determined the gait parameters of 20 healthy subjects with right-foot preference during treadmill walking at speeds of 1.1, 1.4 and 1.7 m/s. We found that when the value of the gait parameter was conspicuously greater (smaller) than the mean value, it was either followed immediately by a smaller (greater) value of the contralateral leg (interleg control), or the deviation from the mean value decreased during the next movement of ipsilateral leg (intraleg control). The selection of step duration and the selection of step length during such transient control events were performed in unique ways. We quantified the symmetry of short-term control of gait parameters and observed the significant dominance of the right leg in short-term control of all three parameters at higher speeds (1.4 and 1.7 m/s).

Increased foot-stretcher height improves rowing performance: evidence from biomechanical perspectives on water.

PubMed

Liu, Yang; Gao, Binghong; Li, Jiru; Ma, Zuchang; Sun, Yining

2018-06-07

The aim of this study was to investigate whether changes on foot-stretcher height were associated with characteristics of better rowing performance. Ten male rowers performed a 200 m rowing trial at their racing rate at each of three foot-stretcher heights. A single scull was equipped with an accelerometer to collect boat acceleration, an impeller with embedded magnets to collect boat speed, specially designed gate sensors to collect gate force and angle, and a compact string potentiometer to collect leg drive length. All sensor signals were sampled at 50 Hz. A one-way repeated measures ANOVA showed that raising foot-stretcher position had a significant reduction on total gate angle and leg drive length. However, a raised foot-stretcher position had a deeper negative peak of boat acceleration at the catch, a lower boat fluctuation, a faster leg drive speed, a larger gate force for the port and starboard side separately. This could be attributed to the optimisation of the magnitude and direction of the foot force with a raised foot-stretcher position. Although there was a significant negative influence of a raised foot-stretcher position on two kinematic variables, biomechanical evidence suggested that a raised foot-stretcher position could contribute to the improvement of rowing performance.

EMG synchrony to assess impaired corticomotor control of locomotion after stroke.

PubMed

Lodha, Neha; Chen, Yen-Ting; McGuirk, Theresa E; Fox, Emily J; Kautz, Steven A; Christou, Evangelos A; Clark, David J

2017-12-01

Adapting one's gait pattern requires a contribution from cortical motor commands. Evidence suggests that frequency-based analysis of electromyography (EMG) can be used to detect this cortical contribution. Specifically, increased EMG synchrony between synergistic muscles in the Piper frequency band has been linked to heightened corticomotor contribution to EMG. Stroke-related damage to cerebral motor pathways would be expected to diminish EMG Piper synchrony. The objective of this study is therefore to test the hypothesis that EMG Piper synchrony is diminished in the paretic leg relative to nonparetic and control legs, particularly during a long-step task of walking adaptability. Twenty adults with post-stroke hemiparesis and seventeen healthy controls participated in this study. EMG Piper synchrony increased more for the control legs compare to the paretic legs when taking a non-paretic long step (5.02±3.22% versus 0.86±2.62%), p<0.01) and when taking a paretic long step (2.04±1.98% versus 0.70±2.34%, p<0.05). A similar but non-significant trend was evident when comparing non-paretic and paretic legs. No statistically significant differences in EMG Piper synchrony were found between legs for typical walking. EMG Piper synchrony was positively associated with walking speed and step length within the stroke group. These findings support the assertion that EMG Piper synchrony indicates corticomotor contribution to walking. Published by Elsevier Ltd.

Impact of stance phase microprocessor-controlled knee prosthesis on ramp negotiation and community walking function in K2 level transfemoral amputees.

PubMed

Burnfield, Judith M; Eberly, Valerie J; Gronely, Joanne K; Perry, Jacquelin; Yule, William Jared; Mulroy, Sara J

2012-03-01

Microprocessor controlled prosthetic knees (MPK) offer opportunities for improved walking stability and function, but some devices' swing phase features may exceed needs of users with invariable cadence. One MPK offers computerized control of only stance (C-Leg Compact). To assess Medicare Functional Classification Level K2 walkers' ramp negotiation performance, function and balance while using a non-MPK (NMPK) compared to the C-Leg Compact. Crossover. Gait while ascending and descending a ramp (stride characteristics, kinematics, electromyography) and function were assessed in participant's existing NMPK and again in the C-Leg Compact following accommodation. Ramp ascent and descent were markedly faster in the C-Leg Compact compared to the NMPK (p ≤ 0.006), owing to increases in stride length (p ≤ 0.020) and cadence (p ≤ 0.020). Residual limb peak knee flexion and ankle dorsiflexion were significantly greater (12.9° and 4.9° more, respectively) during single limb support while using the C-Leg Compact to descend ramps. Electromyography (mean, peak) did not differ significantly between prosthesis. Function improved in the C-Leg Compact as evidenced by a significantly faster Timed Up and Go and higher functional questionnaire scores. Transfemoral K2 walkers exhibited significantly improved function and balance while using the stance-phase only MPK compared to their traditional NMPK.

Bilateral asymmetries in max effort single-leg vertical jumps.

PubMed

Stephens, Thomas M; Lawson, Brooke R; Reiser, Raoul F

2005-01-01

While asymmetries in the lower extremity during jumping may have implications during rehabilitation, it is not clear if healthy subjects should be expected to jump equivalently on each leg. Therefore, the goal of this study was to determine if asymmetries exist in maximal effort single-leg vertical jumps. After obtaining university-approved informed consent, 13 men and 12 women with competitive volleyball playing experience and no injuries of the lower-extremity that would predispose them to asymmetries participated. After thorough warm-up, five maximal effort vertical jumps with countermovement were performed on each leg (random order) with ground reaction forces and lower extremity kinematics recorded. The best three jumps from each leg were analyzed, assigning the leg with the highest jump height average as the dominant side. Asymmetry was assessed by determining statistical significance in the dominant versus non-dominant sides (p < 0.05). A significant interaction existed between side and gender for thigh length and peak vertical ground reaction force. Women had a significantly shorter thigh and men a greater peak vertical ground reaction force on their dominant side. All other parameters were assessed as whole group. Jumps were significantly greater off the dominant leg (2.8 cm on average). No other differences between sides were observed. Significant differences in magnitude (p < 0.05) existed between the men and women in jump height, several anthropometric parameters, minimum ankle and hip angles, and vertical ground reaction forces (peak and average). In conclusion, though a person may jump slightly higher on one leg relative to the other, and women may jump slightly differently than men, the magnitude of the difference should be relatively small and due to the multi-factorial nature of jump performance, individual parameters related to performance may not be consistently different.

Genome-wide Analysis of Body Proportion Classifies Height-Associated Variants by Mechanism of Action and Implicates Genes Important for Skeletal Development.

PubMed

Chan, Yingleong; Salem, Rany M; Hsu, Yu-Han H; McMahon, George; Pers, Tune H; Vedantam, Sailaja; Esko, Tonu; Guo, Michael H; Lim, Elaine T; Franke, Lude; Smith, George Davey; Strachan, David P; Hirschhorn, Joel N

2015-05-07

Human height is a composite measurement, reflecting the sum of leg, spine, and head lengths. Many common variants influence total height, but the effects of these or other variants on the components of height (body proportion) remain largely unknown. We studied sitting height ratio (SHR), the ratio of sitting height to total height, to identify such effects in 3,545 African Americans and 21,590 individuals of European ancestry. We found that SHR is heritable: 26% and 39% of the total variance of SHR can be explained by common variants in European and African Americans, respectively, and global European admixture is negatively correlated with SHR in African Americans (r(2) ≈ 0.03). Six regions reached genome-wide significance (p < 5 × 10(-8)) for association with SHR and overlapped biological candidate genes, including TBX2 and IGFBP3. We found that 130 of 670 height-associated variants are nominally associated (p < 0.05) with SHR, more than expected by chance (p = 5 × 10(-40)). At these 130 loci, the height-increasing alleles are associated with either a decrease (71 loci) or increase (59 loci) in SHR, suggesting that different height loci disproportionally affect either leg length or spine/head length. Pathway analyses via DEPICT revealed that height loci affecting SHR, and especially those affecting leg length, show enrichment of different biological pathways (e.g., bone/cartilage/growth plate pathways) than do loci with no effect on SHR (e.g., embryonic development). These results highlight the value of using a pair of related but orthogonal phenotypes, in this case SHR with height, as a prism to dissect the biology underlying genetic associations in polygenic traits and diseases. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Gait characteristics under different walking conditions: Association with the presence of cognitive impairment in community-dwelling older people

PubMed Central

Fransen, Erik; Perkisas, Stany; Verhoeven, Veronique; Beauchet, Olivier; Remmen, Roy

2017-01-01

Background Gait characteristics measured at usual pace may allow profiling in patients with cognitive problems. The influence of age, gender, leg length, modified speed or dual tasking is unclear. Methods Cross-sectional analysis was performed on a data registry containing demographic, physical and spatial-temporal gait parameters recorded in five walking conditions with a GAITRite® electronic carpet in community-dwelling older persons with memory complaints. Four cognitive stages were studied: cognitively healthy individuals, mild cognitive impaired patients, mild dementia patients and advanced dementia patients. Results The association between spatial-temporal gait characteristics and cognitive stages was the most prominent: in the entire study population using gait speed, steps per meter (translation for mean step length), swing time variability, normalised gait speed (corrected for leg length) and normalised steps per meter at all five walking conditions; in the 50-to-70 years old participants applying step width at fast pace and steps per meter at usual pace; in the 70-to-80 years old persons using gait speed and normalised gait speed at usual pace, fast pace, animal walk and counting walk or steps per meter and normalised steps per meter at all five walking conditions; in over-80 years old participants using gait speed, normalised gait speed, steps per meter and normalised steps per meter at fast pace and animal dual-task walking. Multivariable logistic regression analysis adjusted for gender predicted in two compiled models the presence of dementia or cognitive impairment with acceptable accuracy in persons with memory complaints. Conclusion Gait parameters in multiple walking conditions adjusted for age, gender and leg length showed a significant association with cognitive impairment. This study suggested that multifactorial gait analysis could be more informative than using gait analysis with only one test or one variable. Using this type of gait analysis in clinical practice could facilitate screening for cognitive impairment. PMID:28570662

Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

PubMed

Markowitz, Jared; Herr, Hugh

2016-05-01

Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG), and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT) values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured) with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

Postural Control Characteristics during Single Leg Standing of Individuals with a History of Ankle Sprain: Measurements Obtained Using a Gravicorder and Head and Foot Accelerometry.

PubMed

Abe, Yota; Sugaya, Tomoaki; Sakamoto, Masaaki

2014-03-01

[Purpose] This study aimed to validate the postural control characteristics of individuals with a history of ankle sprain during single leg standing by using a gravicorder and head and foot accelerometry. [Subjects] Twenty subjects with and 23 subjects without a history of ankle sprain (sprain and control groups, respectively) participated. [Methods] The anteroposterior, mediolateral, and total path lengths, as well as root mean square (RMS) of each length, were calculated using the gravicorder. The anteroposterior, mediolateral, and resultant acceleration of the head and foot were measured using accelerometers and were evaluated as the ratio of the acceleration of the head to the foot. [Results] There was no significant difference between the two groups in path length or RMS acceleration of the head and foot. However, the ratios of the mediolateral and resultant components were significantly higher in the sprain group than in the control group. [Conclusion] Our findings suggest that individuals with a history of ankle sprain have a higher head-to-foot acceleration ratio and different postural control characteristics than those of control subjects.

Gender differences in adult foot shape: implications for shoe design.

PubMed

Wunderlich, R E; Cavanagh, P R

2001-04-01

To analyze gender differences in foot shape in a large sample of young individuals. Univariate t-tests and multivariate discriminant analyses were used to assess 1) significant differences between men and women for each foot and leg dimension, standardized to foot length, 2) the reliability of classification into gender classes using the absolute and standardized variable sets, and 3) the relative importance of each variable to the discrimination between men and women. Men have longer and broader feet than women for a given stature. After normalization of the measurements by foot length, men and women were found to differ significantly in two calf, five ankle, and four foot shape variables. Classification by gender using absolute values was correct at least 93% of the time. Using the variables standardized to foot length, gender was correctly classified 85% of the time. This study demonstrates that female feet and legs are not simply scaled-down versions of male feet but rather differ in a number of shape characteristics, particularly at the arch, the lateral side of the foot, the first toe, and the ball of the foot. These differences should be taken into account in the design and manufacture of women's sport shoes.

Coordination of multiple appendages in drag-based swimming.

PubMed

Alben, Silas; Spears, Kevin; Garth, Stephen; Murphy, David; Yen, Jeannette

2010-11-06

Krill are aquatic crustaceans that engage in long distance migrations, either vertically in the water column or horizontally for 10 km (over 200,000 body lengths) per day. Hence efficient locomotory performance is crucial for their survival. We study the swimming kinematics of krill using a combination of experiment and analysis. We quantify the propulsor kinematics for tethered and freely swimming krill in experiments, and find kinematics that are very nearly metachronal. We then formulate a drag coefficient model which compares metachronal, synchronous and intermediate motions for a freely swimming body with two legs. With fixed leg velocity amplitude, metachronal kinematics give the highest average body speed for both linear and quadratic drag laws. The same result holds for five legs with the quadratic drag law. When metachronal kinematics is perturbed towards synchronous kinematics, an analysis shows that the velocity increase on the power stroke is outweighed by the velocity decrease on the recovery stroke. With fixed time-averaged work done by the legs, metachronal kinematics again gives the highest average body speed, although the advantage over synchronous kinematics is reduced.

Zinc finger protein rotund deficiency affects development of the thoracic leg in Bombyx mori.

PubMed

Zhou, Chun-Yan; Zha, Xing-Fu; Liu, Hua-Wei; Xia, Qing-You

2017-06-01

The insect limb develops from the imaginal disc or larval leg during metamorphosis. The molecular mechanisms involved in the development from the larval to the adult leg are poorly understood. Herein, we cloned the full length of a zinc finger gene rotund from Bombyx mori (Bmrn), which contained a 1419 bp open reading frame, and encoded a 473 amino acid protein. Reverse transcription polymerase chain reaction and Western blot analyses demonstrated that Bmrn was expressed at higher levels in the epidermis than in other tissues tested, and it showed a very high expression level during metamorphosis. Knock-down of Bmrn produced defects in the tarsus and pretarsus, including the fusion and reduction of tarsomeres, and the developmental arrest of pretarsus. Our data showed that Bmrn is involved in the formation of the tarsus and pretarsus, whereas its homologous gene in Drosophila has been shown to affect three tarsal segments (t2-t4), suggesting that the remodeling of the leg has involved changes in the patterning of gene regulation during evolution. © 2016 Institute of Zoology, Chinese Academy of Sciences.

A new index of flat breaststroke propulsion: a comparison of elite men and women.

PubMed

Seifert, L; Chollet, D

2005-03-01

This study examined arm and leg coordination and propulsion during the flat breaststroke in nine elite male and eight elite female swimmers over three race paces (200 m, 100 m and 50 m). Coordination was expressed using four temporal gaps (T1, T2, T3, T4), which described the continuity between the propulsive phases of the limbs, as recorded on a video device (50 Hz). Glide duration was denoted T1, the time between the beginning of arm and leg recovery was denoted T2, the time between the end of arm and the leg recovery was denoted T3, and the time between 90 degrees of flexion during arm recovery and 90 degrees during leg recovery was denoted T4. Using these temporal gaps, four stroke phases (propulsion, glide, recovery and leg insweep) could be followed over a complete arm and leg stroke. The total duration of arm and leg propulsion was assessed by a new index of flat breaststroke propulsion (IFBP). Velocity, stroke rate and stroke length were also calculated for each pace. The elite swimmers showed short T2, T3 and T4; moreover, T1 decreased when the pace increased. Expertise in the flat breaststroke was thus characterized by synchronized arm and leg recoveries and increased continuity in the arm and leg propulsions with increasing velocity. Differences between the sexes in the spatio-temporal parameters were possibly due to anthropometric differences (the men were heavier, older and taller than the women) and different motor organization linked to arm and leg coordination (shorter T3, body glide and body recovery, and greater body propulsion and higher IFBP in the men). The men's propulsive actions showed greater continuity, particularly in the sprint. The best men adopted a superposition coordination and thus had the ability to overcome very great active drag. Temporal gap measurement and the IFBP are practical indicators of arm and leg coordination and propulsion that can be exploited by coaches and swimmers to increase the continuity between propulsive actions during the flat breaststroke.

Somatic Profile of the Elite Boulderers in Poland.

PubMed

Ozimek, Mariusz; Krawczyk, Marcin; Zadarko, Emilian; Barabasz, Zbigniew; Ambroży, Tadeusz; Stanula, Arkadiusz; Mucha, Dawid K; Jurczak, Adam; Mucha, Dariusz

2017-04-01

Ozimek, M, Krawczyk, M, Zadarko, E, Barabasz, Z, Ambroży, T, Stanula, A, Mucha, DK, Jurczak, A, and Mucha, D. Somatic profile of the elite boulderers in Poland. J Strength Cond Res 31(4): 963-970, 2017-The study was designed to determine the values of selected somatic characteristics, body proportions, and the somatotype of elite bouldering climbers in Poland and to establish the relationships between the values of the somatic characteristics and climber's performance in bouldering. The study was conducted in a group of elite sport climbers (n = 10) who were ranked by the Polish Mountaineering Association in 2011, 2012, and 2013. The anthropometric measurements were made according to the relevant rules and standards. The results were used to calculate the values of somatic variables and body proportion indices for the climbers and to establish their somatotype. The results were compared with the data on untrained students (n = 165). The boulderers were found to differ significantly from the controls regarding body height (p < 0.01), body mass (p ≤ 0.05), body density (p < 0.01), fat mass percentage (FM%) (p < 0.01), fat mass (FMkg) (p < 0.01), lean body mass (p ≤ 0.05), arm span (p ≤ 0.05), and leg length (p < 0.01). Body proportions in the groups significantly differed in the arm length index (p < 0.01), arm-to-leg length ratio (p < 0.01), and in the indices of the forearm (p < 0.01), thigh (p < 0.01), and lower leg (p ≤ 0.05) muscles. With regard to the somatotypes of the analyzed groups, the biggest differences were observed for the levels of mesomorphy (NS) and endomorphy, the latter being statistically significant (p < 0.01). The strongest and significant correlations between the competitive level of the climbers and the values of their somatic characteristics were established for FM% (r = -0.81), fat mass (in kilograms) (r = -0.82), body density (r = 0.81), endomorphy (r = -0.74), arm length (r = 0.77), and the arm length index (r = 0.80). The results of linear regression showed that the competitive level of a bouldering climber was significantly explained (p < 0.01) by fat mass (in kilograms) and the value of the arm length index. A high level of performance in bouldering is related to small stature (an ecto-mesomorph somatotype) and a low body fat percentage (low endomorphy). Regarding body proportions, greater than average arm length to body height ratio and well-developed musculature of the limbs are required for a boulderer to perform on a competitive level. High arm length index and low body fat percentage represent the strongest determinants of performance in bouldering. It can be assumed that arm length index has a high diagnostic value for recruitment and selection of climbers.

Experience with latrogenic pediatric vascular injuries. Incidence, etiology, management, and results.

PubMed Central

Flanigan, D P; Keifer, T J; Schuler, J J; Ryan, T J; Castronuovo, J J

1983-01-01

During a 32-month period, 79 extremities in 76 children (age 1 day-13 years, mean = 31 months) were evaluated with regard to iatrogenic vascular injuries. Prospectively, 42 children were studied pre- and post-cardiac catheterization. Ten of these children sustained vascular injuries (incidence = 24%). Thirty-four additional children were referred because of 35 iatrogenic vascular injuries as a result of transfemoral cardiac catheterization (n = 20), umbilical artery catheterization (n = 10), or recent surgery (n = 5). All 45 injuries were evaluated by lower extremity segmental Doppler pressure measurements in addition to routine physical examination at the time of injury and at frequent follow-up. An ankle/brachial pressure index (ABI) less than 0.9 was considered abnormal. Selected children (ABI less than 0.9 for greater than 30 days) underwent orthoroentgenograms to assess limb growth. The average ABI immediately following injury was 0.34 +/- 0.33. Thirty-four injuries were treated nonoperatively. Twelve injuries were excluded from further study due to death (n = 7) or being lost to follow-yp (n = 5). A return of ABI to normal was seen from 1 day to 2 years in 93% of children treated with heparin (n = 14) compared to 63% of children who were simply observed (n = 8) (p less than 0.10). The initial severity of ischemia did not correlate with the subsequent rate of improvement. Only patients with absent femoral pulses were selected for operative intervention, which consisted of aortic thrombectomy (n = 2), femorofemoral bypass (n = 2), femoral artery patch angioplasty (n = 1), or femoral artery thrombectomy (n = 7) with no mortality. Nine patients had immediate return of a normal ABI after surgery. A delayed return of ABI to normal occurred in the other two. Nine per cent of surgically treated children and 23% of nonsurgically treated children developed leg length discrepancies (0.5-3.0 cm) as a result of ischemia lasting greater than 30 days. Overall, 91% of the children in this series eventually regained normal circulation following injury and no child lost a limb. This study indicates that iatrogenic pediatric vascular injuries are common and can result in significant limb growth impairment. Immediate operative intervention is highly successful when the injury is proximal to the common femoral artery bifurcation and avoids the prolonged ischemia seen with nonoperative therapy. For more distal occlusions, heparin therapy provides better results than simple observation. Although therapeutic intervention for these injuries is generally successful, a limb length discrepancy rate of 14% mandates that indications for invasive vascular monitoring and diagnostic procedures be strict. Images Fig. 2. Fig. 7. PMID:6625714

Effects of incubator temperature and oxygen concentration during the plateau stage of oxygen consumption on Turkey embryo long bone development.

PubMed

Oviedo-Rondón, E O; Small, J; Wineland, M J; Christensen, V L; Grimes, J L; Funderburk, S V L; Ort, D T; Mann, K M

2008-08-01

Temperature (TEM) and O(2) concentrations during the plateau stage of oxygen consumption are known to affect yolk utilization, tissue development, and thyroid metabolism in turkey embryos. Three experiments were conducted to evaluate these incubation effects on long bone development. Fertile eggs of Nicholas turkeys were used. In each trial, standard incubation conditions were used to 24 d, when the eggs containing viable embryos were randomly divided into 4 groups. Four experimental cabinets provided 4 TEM (36, 37, 38, or 39 degrees C) or 4 O(2) concentrations (17, 19, 21, or 23% O(2)). In the third experiment, 2 temperatures (36 and 39 degrees C) and 2 O(2) concentrations (17 and 23%) were evaluated in a 2 x 2 factorial design. Body and residual yolk weights were obtained. Both legs were dissected, and shanks, femur, and tibia weights, length, and thickness were recorded. Relative asymmetry of each leg section was calculated. Chondrocyte density was evaluated in slides stained with hematoxylin and eosin. Immunofluorescence was used to evaluate the presence of collagen type X and transforming growth factor beta. Hot TEM caused reduction of tibia weights and increase of shank weight when compared with cool TEM. The lengths of femur, tibia, and shanks were reduced by 39 degrees C. The relative asymmetry of leg weights were increased at 38 and 39 degrees C. Poult body and part weights were not affected by O(2) concentrations, but poults on 23% O(2) had bigger shanks and heavier tibias than the ones on 17% O(2). High TEM depressed the fluorescence of collagen type X and transforming growth factor beta. The O(2) concentrations did not consistently affect the immunofluorescence of these proteins. The chondrocyte density was affected by TEM and O(2) in resting and hypertrophic zones. In the third experiment, high TEM depressed BW, leg muscle weights, and shank length. Low O(2) reduced tibia and shanks as a proportion of the whole body. We concluded that incubation conditions affect long bone development in turkeys.

Changes in kinematics and arm-leg coordination during a 100-m breaststroke swim.

PubMed

Oxford, Samuel W; James, Rob S; Price, Michael J; Payton, Carl J; Duncan, Michael J

2017-08-01

The purpose of this study was to compare arm-leg coordination and kinematics during 100 m breaststroke in 26 (8 female; 18 male) specialist breaststroke swimmers. Laps were recorded using three 50-Hz underwater cameras. Heart rate and blood lactate were measured pre- and post-swim. Arm-leg coordination was defined using coordination phases describing continuity between recovery and propulsive phases of upper and lower limbs: coordination phase 1 (time between end of leg kick and start of the arm pull phases); and coordination phase 2 (time between end of arm pull and start of leg kick phases). Duration of stroke phases, coordination phases, swim velocity, stroke length (SL), stroke rate (SR) and stroke index (SI) were analysed during the last three strokes of each lap that were unaffected by turning or finishing. Significant changes in velocity, SI and SL (P < 0.05) were found between laps. Both sexes showed significant increase (P < 0.05) in heart rate and blood lactate pre- to post-swim. Males had significantly (P < 0.01) faster swim velocities resulting from longer SLs (P = 0.016) with no difference in SR (P = 0.064). Sex differences in kinematic parameters can be explained by anthropometric differences providing males with increased propelling efficiency.

A review of models of vertical, leg, and knee stiffness in adults for running, jumping or hopping tasks.

PubMed

Serpell, Benjamin G; Ball, Nick B; Scarvell, Jennie M; Smith, Paul N

2012-01-01

The 'stiffness' concept originates from Hooke's law which states that the force required to deform an object is related to a spring constant and the distance that object is deformed. Research into stiffness in the human body is undergoing unprecedented popularity; possibly because stiffness has been associated with sporting performance and some lower limb injuries. However, some inconsistencies surrounding stiffness measurement exists bringing into question the integrity of some research related to stiffness. The aim of this study was to review literature which describes how vertical, leg and knee stiffness has been measured in adult populations while running, jumping or hopping. A search of the entire MEDLINE, PubMed and SPORTDiscus databases and an iterative reference check was performed. Sixty-seven articles were retrieved; 21 measured vertical stiffness, 51 measured leg stiffness, and 22 measured knee stiffness. Thus, some studies measured several 'types' of stiffness. Vertical stiffness was typically the quotient of ground reaction force and centre of mass displacement. For leg stiffness it was and change in leg length, and for the knee it was the quotient of knee joint moments and change in joint angle. Sample size issues and measurement techniques were identified as limitations to current research.

Is There an Economical Running Technique? A Review of Modifiable Biomechanical Factors Affecting Running Economy.

PubMed

Moore, Isabel S

2016-06-01

Running economy (RE) has a strong relationship with running performance, and modifiable running biomechanics are a determining factor of RE. The purposes of this review were to (1) examine the intrinsic and extrinsic modifiable biomechanical factors affecting RE; (2) assess training-induced changes in RE and running biomechanics; (3) evaluate whether an economical running technique can be recommended and; (4) discuss potential areas for future research. Based on current evidence, the intrinsic factors that appeared beneficial for RE were using a preferred stride length range, which allows for stride length deviations up to 3 % shorter than preferred stride length; lower vertical oscillation; greater leg stiffness; low lower limb moment of inertia; less leg extension at toe-off; larger stride angles; alignment of the ground reaction force and leg axis during propulsion; maintaining arm swing; low thigh antagonist-agonist muscular coactivation; and low activation of lower limb muscles during propulsion. Extrinsic factors associated with a better RE were a firm, compliant shoe-surface interaction and being barefoot or wearing lightweight shoes. Several other modifiable biomechanical factors presented inconsistent relationships with RE. Running biomechanics during ground contact appeared to play an important role, specifically those during propulsion. Therefore, this phase has the strongest direct links with RE. Recurring methodological problems exist within the literature, such as cross-comparisons, assessing variables in isolation, and acute to short-term interventions. Therefore, recommending a general economical running technique should be approached with caution. Future work should focus on interdisciplinary longitudinal investigations combining RE, kinematics, kinetics, and neuromuscular and anatomical aspects, as well as applying a synergistic approach to understanding the role of kinetics.

Reference charts of sitting height, leg length and body proportions for Chinese children aged 0-18 years.

PubMed

Zhang, Ya-qin; Li, Hui

2015-01-01

The reference charts of sitting height (SH), subischial leg length (LL) and the sitting height/leg length ratio (SH/LL) are useful tools in assessing body proportion for clinicians and researchers in related areas. However, reference charts of body proportions for Chinese children and adolescents are limited. To construct reference charts of SH, LL and SH/LL for Chinese children and adolescents. Stature and sitting height of 92 494 (46 240 boys and 46 254 girls) healthy Han nationality children, aged 0-18 years, were measured in two national large-scale cross-sectional surveys in 2005 in China. SH/LL was selected as the indicator of body proportion. References of SH, LL and SH/LL were constructed using the LMS method. The reference charts demonstrated that SH and LL increased with age. Growth in SH slowed by the age of 17 years in boys and 15 years in girls. Similarly, growth in LL slowed at 16 years in boys and 14 years in girls. The SH/LL ratio declined from birth (2.00 in boys and 2.03 in girls) to 13 years in boys (1.11) and to 11 years in girls (1.13), then increased slightly to the age of 18 (1.16 in boys and 1.18 in girls). The gender difference of SH/LL was not significantly different before the age of 11 years. After the age of 11, SH/LL appeared elevated in girls compared to boys. The reference charts of SH, LL and SH/LL are useful tools for assessing body proportions for Chinese children and adolescent individuals.

Genotype and phenotype in hypochondroplasia.

PubMed

Ramaswami, U; Rumsby, G; Hindmarsh, P C; Brook, C G

1998-07-01

Mutations in the tyrosine kinase domain of fibroblast growth factor receptor gene (FGFR3) have been described in some cases of hypochondroplasia (Hch). We screened 65 children with Hch diagnosed by clinical and radiologic criteria for 2 previously described mutations, C1620A and C1620C in FGFR3; 28 (43%) of 65 patients were heterozygous for the C1620A transversion resulting in lysine to asparagine substitution at codon 540 in the tyrosine kinase domain of FGFR3. The height, sitting height, and subischial leg length of these children and of 18 children with achondroplasia were analyzed at presentation, and SD scores were calculated. For comparison of growth data the patients were divided into three groups: group 1, achondroplasia defined by radiology and the presence of the G1138A mutation in the transmembrane domain of FGFR3; group 2, Hch with C1620A mutation; and group 3, Hch with no mutation identified so far. Height, sitting height, and subischial leg length SD scores were analyzed as group mean data by analysis of variance with the Student Neuman-Keuls test after testing for multiple contrasts were performed. All three groups were significantly compromised in height, although the children with achondroplasia were much shorter with significant reduction in subischial leg length. The same pattern was evident in group 2, with additional shortening of the back, the third group was proportionately short. Children with the common C1620A mutation met all of the criteria for the diagnosis of Hch with a severe phenotype that resembled achondroplasia and disproportionate short stature in early childhood. However, a substantial number of patients with proportionate short stature presented at an older age with the same radiologic characteristics and failure of the puberty growth spurt. The genetic basis of this milder phenotype not yet known.

Body configuration at first stepping-foot contact predicts backward balance recovery capacity in people with chronic stroke.

PubMed

de Kam, Digna; Roelofs, Jolanda M B; Geurts, Alexander C H; Weerdesteyn, Vivian

2018-01-01

To determine the predictive value of leg and trunk inclination angles at stepping-foot contact for the capacity to recover from a backward balance perturbation with a single step in people after stroke. Twenty-four chronic stroke survivors and 21 healthy controls were included in a cross-sectional study. We studied reactive stepping responses by subjecting participants to multidirectional stance perturbations at different intensities on a translating platform. In this paper we focus on backward perturbations. Participants were instructed to recover from the perturbations with maximally one step. A trial was classified as 'success' if balance was restored according to this instruction. We recorded full-body kinematics and computed: 1) body configuration parameters at first stepping-foot contact (leg and trunk inclination angles) and 2) spatiotemporal step parameters (step onset, step length, step duration and step velocity). We identified predictors of balance recovery capacity using a stepwise logistic regression. Perturbation intensity was also included as a predictor. The model with spatiotemporal parameters (perturbation intensity, step length and step duration) could correctly classify 85% of the trials as success or fail (Nagelkerke R2 = 0.61). In the body configuration model (Nagelkerke R2 = 0.71), perturbation intensity and leg and trunk angles correctly classified the outcome of 86% of the recovery attempts. The goodness of fit was significantly higher for the body configuration model compared to the model with spatiotemporal variables (p<0.01). Participant group and stepping leg (paretic or non-paretic) did not significantly improve the explained variance of the final body configuration model. Body configuration at stepping-foot contact is a valid and clinically feasible indicator of backward fall risk in stroke survivors, given its potential to be derived from a single sagittal screenshot.

Vibration-related extrusion of capillary blood from the calf musculature depends upon directions of vibration of the leg and of the gravity vector.

PubMed

Çakar, Halil Ibrahim; Doğan, Serfiraz; Kara, Sadık; Rittweger, Jörn; Rawer, Rainer; Zange, Jochen

2017-06-01

In this study, we investigated the effects of vibration of the whole lower leg on the content and the oxygenation of hemoglobin in the unloaded relaxed lateral gastrocnemius muscle. Vibration was applied orthogonal to and in parallel with leg axis to examine whether the extrusion of blood depends on an alignment of main vessel direction, axis of vibration and gravity. The blood volume in the muscles was altered by horizontal and 30° upright body posture. Fifteen male subjects were exposed to 4 sets of experiments with both vibration directions and both tilt angles applied in permutated order. The absence of voluntary muscular activity and the potential occurrence of compound action potentials by stretch reflexes were monitored using electromyography. Total hemoglobin and tissue saturation index were measured with near infrared spectroscopy. Changes of lower leg circumference were measured with strain gauge system placed around the calf. Vibration caused decrease in tHb and increase in TSI indicating extrusion of predominantly venous blood from the muscle. In 30° tilted position, muscles contained more blood at baseline and vibration ejected more blood from the muscle compared with horizontal posture (p < 0.01). At 30° tilting deeper drop in tHb and steeper increase in TSI (p < 0.01) were observed when vibration was applied in parallel with the length axis of muscle. It is concluded that the vibration extrudes more blood in 30° head up posture and the vibration applied in parallel with the length axis of the muscle is more effective than orthogonal vibration.

Sex differences in leg dexterity are not present in elite athletes.

PubMed

Lawrence, Emily L; Peppoloni, Lorenzo; Valero-Cuevas, Francisco J

2017-10-03

We studied whether the time-varying forces that control unstable foot-ground interactions provide insight into the neural control of dynamic leg function. Twenty elite (10F, 26.4±3.5yrs) and 20 recreational (10F, 24.8±2.4yrs) athletes used an isolated leg to maximally compress a slender spring designed to buckle at low forces while seated. The foot forces during the compression at the edge of instability quantify the maximal sensorimotor ability to control dynamic foot-ground interactions. Using the nonlinear analysis technique of attractor reconstruction, we characterized the spatial (interquartile range IQR) and geometric (trajectory length TL, volume V, and sum of edge lengths SE) features of the dynamical behavior of those force time series. ANOVA confirmed the already published effect of sex, and a new effect of athletic ability, respectively, in TL (p=0.014 and p<0.001), IQR (p=0.008 and p<0.001), V (p=0.034 and p=0.002), and SE (p=0.033 and p<0.001). Further analysis revealed that, for recreational athletes, females exhibited weaker corrective actions and greater stochasticity than males as per their greater mean values of TL (p=0.003), IQR (p=0.018), V (p=0.017), and SE (p=0.025). Importantly, sex differences disappeared in elite athletes. These results provide an empirical link between sex, athletic ability, and nonlinear dynamical control. This is a first step in understanding the sensorimotor mechanisms for control of unstable foot-ground interactions. Given that females suffer a greater incidence of non-contact knee ligament injuries, these non-invasive and practical metrics of leg dexterity may be both indicators of athletic ability, and predictors of risk of injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Novel Perforator Flap Training Model Using a Chicken Leg.

PubMed

Cifuentes, Ignacio J; Yañez, Ricardo A; Salisbury, Maria C; Rodriguez, José R; Varas, Julian E; Dagnino, Bruno L

2016-04-01

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Severe valgus deformity of the knee with permanent patellar dislocation associated with melorheostosis: a case report and review of the literature.

PubMed

Kitta, Yuki; Niki, Yasuo; Udagawa, Kazuhiko; Enomoto, Hiroyuki; Toyama, Yoshiaki; Suda, Yasunori

2014-03-01

We present a case of an 8-year-old boy diagnosed with melorheostosis who was suffering from severe genu valgum, permanent dislocation of the patella, knee flexion contracture and leg length shortening. Soft tissue contracture of the limb and subsequent joint deformities were reported to represent clinical manifestations of pediatric melorheostosis. As the epiphyseal plate had not closed, patellar reduction was achieved by soft tissue surgical stabilization, including lateral retinacular release, medial retinaculum plication, and transfer of the lateral half of the patellar tendon. At 4 years postoperatively, as a result of improved limb alignment and knee flexion contracture, the leg length shortening has improved, and the patient does not limp and participates in sports activities. Surgical intervention should be performed as early as possible, because genu valgum and external rotation of the tibia may deteriorate with age, rendering the patellar dislocation irreversible in patients with melorheostosis before epiphyseal closure. Copyright © 2012 Elsevier B.V. All rights reserved.

Comprehensive non-dimensional normalization of gait data.

PubMed

Pinzone, Ornella; Schwartz, Michael H; Baker, Richard

2016-02-01

Normalizing clinical gait analysis data is required to remove variability due to physical characteristics such as leg length and weight. This is particularly important for children where both are associated with age. In most clinical centres conventional normalization (by mass only) is used whereas there is a stronger biomechanical argument for non-dimensional normalization. This study used data from 82 typically developing children to compare how the two schemes performed over a wide range of temporal-spatial and kinetic parameters by calculating the coefficients of determination with leg length, weight and height. 81% of the conventionally normalized parameters had a coefficient of determination above the threshold for a statistical association (p<0.05) compared to 23% of those normalized non-dimensionally. All the conventionally normalized parameters exceeding this threshold showed a reduced association with non-dimensional normalization. In conclusion, non-dimensional normalization is more effective that conventional normalization in reducing the effects of height, weight and age in a comprehensive range of temporal-spatial and kinetic parameters. Copyright © 2015 Elsevier B.V. All rights reserved.

Prevalence of frontal plane pelvic postural asymmetry--part 1.

PubMed

Juhl, John Henry; Ippolito Cremin, Tonya M; Russell, George

2004-10-01

Despite 80 years of study, questions of how leg length difference relates to recurrent pain and somatic dysfunction remain controversial. The authors hypothesize that a correlation exists between leg length inequality and back pain. They further hypothesize that if common compensatory patterns described in classic osteopathic medical literature exist, these patterns should interact with the pelvic postural asymmetry patterns of Lloyd and Eimerbrink in a predictable, most probable, and congruent fashion. This article reviews the osteopathic medical, as well as the allopathic medical and chiropractic literature for studies that meet criteria for evidence-based comparison. Using lumbar radiographic studies produced with subjects standing, the authors examined the prevalence of six types of pelvic postural asymmetry in a consecutive case series of 421 patients with low back pain. Establishing the frequency of pelvic postural asymmetry patterns is a necessary first step in creating an evidence-based foundation to further clarify postural compensatory patterns. Various correlations between and within these patterns are identified.

The estimated mechanical advantage of the prosimian ankle joint musculature, and implications for locomotor adaptation.

PubMed

Goto, Ryosuke; Kumakura, Hiroo

2013-05-01

In this study we compared the power arm lengths and mechanical advantages attributed to 12 lower leg muscles across three prosimian species. The origins and insertions of the lower leg muscles in Garnett's galago, the ring-tailed lemur, and the slow loris were quantified and correlated with positional behaviour. The ankle joint of the galago has a speed-oriented mechanical system, in contrast to that of the slow loris, which exhibits more power-oriented mechanics. The lemur ankle joint exhibited intermediate power arm lengths and an intermediate mechanical advantage relative to the other primates. This result suggests that the mechanical differences in the ankle between the galago and the lemur, taxa that exhibit similar locomotory repertoires, reflect a difference in the kinematics and kinetics of leaping (i.e. generalised vs. specialised leapers). In contrast to leaping primates, lorises have developed a more power-oriented mechanical system as a foot adaptation for positional behaviours such as bridging or cantilevering in their arboreal habitat. © 2013 Anatomical Society.

Meat quality attributes of Agile Wallabies.

PubMed

Geesink, Geert H; van den Heuvel, Aaron; Hunt, Warren

2017-11-01

Meat quality traits of Agile Wallaby (Macropus agilis) M. longissimus (loin) and M. semimembranosus (topside) were investigated. Both muscles exhibited a relatively high pH (>5.7) and dark colour (L*-, a*-, and b*-values). Aging the loins from 2 to 21days p.m. had a significant effect on shear force. However, the results regarding shear force, myofibrillar fragmentation index (MFI) and degradation of desmin and troponin-T suggested that the aging response largely occurred within 2days p.m. Suspension of carcasses from one leg resulted in a side effect on shear force of the loin at 2 and 7days p.m., but not on sarcomere length or MFI. Topsides from the free hanging leg exhibited lower shear force values (33 vs 42N) and greater sarcomere lengths (2.51 vs 1.84μM). Tenderness, juiciness, flavour and overall liking were higher for loins than topsides. Sensory scores for the loin and topside were slightly lower and similar, respectively, to those reported for lamb. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pilot study of the impact sacroiliac joint manipulation has on walking kinematics using motion analysis technology

PubMed Central

Ward, John S.; Coats, Jesse; Sorrels, Kenneth; Walters, Mathew; Williams, Trevor

2013-01-01

Objective The purpose of this study was to evaluate the feasibility of engaging in a series of larger studies measuring the effect of sacroiliac joint manipulation on walking kinematics using motion analysis technology. Methods Twelve college students engaged in a baseline 90-second gait analysis at 1.5 mph using infrared VICON cameras. Following this, they underwent a prone heel comparison test for functional leg length inequality. Upon examination, participants were then classified as follows: left short leg, right short leg, or no short leg. Participants in each of the 2 short leg branches of this study were then randomized to receive either chiropractic manipulative therapy to the posterior superior iliac spine on the short limb side or no manipulation. Recruitment was ongoing for this pilot study until 1 participant was recruited in each of the following 5 comparative study groups: left short leg—manipulation, left short leg—no manipulation (control 1), right short leg—manipulation, right short leg—no manipulation (control 2), and no short leg (control 3). All participants then underwent another 90-second gait analysis. Data were then grouped and submitted to a blinded biomechanist to determine if there were any unique biomechanical differences between the groups. Results No statistically significant differences were measured because of this being a pilot study with a small sample size. Conclusions The data from this study indicate that a series of larger studies with this design is feasible. PMID:24396314

Three-dimensional Force and Kinematic Interactions in V1 Skating at High Speeds.

PubMed

Stöggl, Thomas; Holmberg, Hans-Christer

2015-06-01

To describe the detailed kinetics and kinematics associated with use of the V1 skating technique at high skiing speeds and to identify factors that predict performance. Fifteen elite male cross-country skiers performed an incremental roller-skiing speed test (Vpeak) on a treadmill using the V1 skating technique. Pole and plantar forces and whole-body kinematics were monitored at four submaximal speeds. The propulsive force of the "strong side" pole was greater than that of the "weak side" (P < 0.01), but no difference was observed for the legs. The poles generated approximately 44% of the total propulsion, being more effective than the legs in this respect (∼59% vs 11%, P < 0.001). Faster skiers exhibited more well-synchronized poling, exhibited more symmetric edging by and forces from the legs, and were more effective in transformation of resultant forces into propulsion. Cycle length was not correlated with either Vpeak or the impulse of total propulsive forces. The present findings provide novel insights into the coordination, kinetics, and kinematics of the arm and leg motion by elite athletes while V1 skating at high speeds. The faster skiers exhibit more symmetric leg motion on the "strong" and "weak" sides, as well as more synchronized poling. With respect to methods, the pressure insoles and three-dimensional kinematics in combination with the leg push-off model described here can easily be applied to all skating techniques, aiding in the evaluation of skiing techniques and comparison of effectiveness.

How to find home backwards? Locomotion and inter-leg coordination during rearward walking of Cataglyphis fortis desert ants.

PubMed

Pfeffer, Sarah E; Wahl, Verena L; Wittlinger, Matthias

2016-07-15

For insects, flexibility in the performance of terrestrial locomotion is a vital part of facing the challenges of their often unpredictable environment. Arthropods such as scorpions and crustaceans can switch readily from forward to backward locomotion, but in insects this behaviour seems to be less common and, therefore, is only poorly understood. Here we present an example of spontaneous and persistent backward walking in Cataglyphis desert ants that allows us to investigate rearward locomotion within a natural context. When ants find a food item that is too large to be lifted up and to be carried in a normal forward-faced orientation, they will drag the load walking backwards to their home nest. A detailed examination of this behaviour reveals a surprising flexibility of the locomotor output. Compared with forward walks with regular tripod coordination, no main coordination pattern can be assigned to rearward walks. However, we often observed leg-pair-specific stepping patterns. The front legs frequently step with small stride lengths, while the middle and the hind legs are characterized by less numerous but larger strides. But still, these specializations show no rigidly fixed leg coupling, nor are they strictly embedded within a temporal context; therefore, they do not result in a repetitive coordination pattern. The individual legs act as separate units, most likely to better maintain stability during backward dragging. © 2016. Published by The Company of Biologists Ltd.

Effects of ipsilateral anterior thigh soft tissue stretching on passive unilateral straight-leg raise.

PubMed

Clark, S; Christiansen, A; Hellman, D F; Hugunin, J W; Hurst, K M

1999-01-01

Randomized 3-group pretest-posttest with blind assessment of outcome. The purpose of this study was to examine the effect of sagittal plane hold-relax exercise applied to the ipsilateral anterior thigh, and prone positioning on passive unilateral straight-leg raise measurements. Straight-leg raising has been viewed as a measurement for hamstring muscle length, but literature suggests that other structures may affect this measurement. Sixty subjects (45 men, 15 women) qualified for inclusion into the study based on a straight-leg raise measurement of < or = 65 degrees. Subjects were randomly assigned to one of three groups: control, static stretch, or sagittal plane hold-relax exercise. Pretest and posttest straight-leg raise measurements of the right lower extremity were performed for each subject. A 1-way ANOVA of the change scores showed a significant difference between groups. A Tukey post hoc analysis of the change scores showed that both treatment groups' means differed significantly from the control group and from each other, with the sagittal plane hold-relax group exhibiting the largest change (mean of 7.8 degrees +/- 2.8 degrees). The results of this study show that sagittal plane hold-relax exercise and passive prone results of this study show that sagittal plane hold-relax and passive prone positioning can significantly increase straight-leg raise range of motion, however the sagittal plane hold-relax stretching of the anterior thigh is more effective than passive prone positioning.

Factors affecting the energy cost of level running at submaximal speed.

PubMed

Lacour, Jean-René; Bourdin, Muriel

2015-04-01

Metabolic measurement is still the criterion for investigation of the efficiency of mechanical work and for analysis of endurance performance in running. Metabolic demand may be expressed either as the energy spent per unit distance (energy cost of running, C r) or as energy demand at a given running speed (running economy). Systematic studies showed a range of costs of about 20 % between runners. Factors affecting C r include body dimensions: body mass and leg architecture, mostly calcaneal tuberosity length, responsible for 60-80 % of the variability. Children show a higher C r than adults. Higher resting metabolism and lower leg length/stature ratio are the main putative factors responsible for the difference. Elastic energy storage and reuse also contribute to the variability of C r. The increase in C r with increasing running speed due to increase in mechanical work is blunted till 6-7 m s(-1) by the increase in vertical stiffness and the decrease in ground contact time. Fatigue induced by prolonged or intense running is associated with up to 10 % increased C r; the contribution of metabolic and biomechanical factors remains unclear. Women show a C r similar to men of similar body mass, despite differences in gait pattern. The superiority of black African runners is presumably related to their leg architecture and better elastic energy storage and reuse.

Innovative trident fixation technique for allograft knee arthrodesis for high-grade osteosarcoma around the knee.

PubMed

Su, Alvin W; Chen, Wei-Ming; Chen, Cheng-Fong; Chen, Tain-Hsiung

2009-11-01

Reconstruction for osteosarcoma around the knee after wide resection faces the challenge of great bone defect and future limb length discrepancy in the skeletally immature patients. Modern prosthetic reconstruction may provide good results, but the longevity may be of concern and may not be affordable in certain communities. Allograft knee arthrodesis still has its role in light of bone stock preservation and cost-effectiveness. We developed the innovative trident fixation technique utilizing three Steinmann pins to minimize limb length inequality without jeopardizing knee fusion stability. Twelve patients were enrolled. The mean age was 11.5 (10-13) years. Two had high-grade osteosarcoma in proximal tibia and others in distal femur. Two patients died of oncological disease. The median follow-up of the disease-free 10 patients was 47 (41-60) months. All allograft-host bone junctions healed uneventfully without major complications except one allograft fracture. The average limb length discrepancy was 1.45 (1.0-2.1) cm at latest follow-up. This straightforward technique was successful in knee arthrodesis with minimized limb length inequality. Accordingly, in light of bone stock preservation and longevity for the young children, it may be a surgical alternative for malignant bone tumors around the knee.

Anthropometry in Klinefelter syndrome--multifactorial influences due to CAG length, testosterone treatment and possibly intrauterine hypogonadism.

PubMed

Chang, Simon; Skakkebæk, Anne; Trolle, Christian; Bojesen, Anders; Hertz, Jens Michael; Cohen, Arieh; Hougaard, David Michael; Wallentin, Mikkel; Pedersen, Anders Degn; Østergaard, John Rosendahl; Gravholt, Claus Højbjerg

2015-03-01

Klinefelter syndrome, 47, XXY (KS), is underdiagnosed partly due to few clinical signs complicating identification of affected individuals. Certain phenotypic traits are common in KS. However, not all aspects of the KS phenotype are well described. To describe anthropometry and body composition in KS and relate findings to biochemistry and X-chromosome related genetic markers. Seventy three KS males referred to our clinic and 73 age-matched controls underwent comprehensive measurements of anthropometry and body composition in a cross-sectional, case-controlled study. Furthermore, genetic analysis for parental origin of the supernumerary X-chromosome, skewed X-chromosome inactivation and androgen receptor (AR) CAG repeat length was done. Anthropometry and body composition in KS and the effect of genotype hereon. KS males were taller (absolute difference: 5.1 cm, P < .001) with longer legs (5.7 cm, P < .001) compared with controls. Furthermore, 2D:4D was increased in KS males (relative effect size: Cohen's d = 0.40), reflecting reduced fetal testosterone exposure. Also, bi-iliac width (0.41), waist (0.52), and hip circumference (0.47) (P < .02 for all), as well as total fat mass (0.74), abdominal fat mass (0.67), and total body fat percentage (0.84) was increased in KS males (P < .001 for all), while bitesticular volume was reduced (4.6). AR CAG repeat length was comparable in KS and controls, and among KS CAG correlated to arm length (P = .04), arm span (P = .01), and leg length (P = .04). Effects of parental origin of the supernumerary X-chromosome and skewed X-chromosome inactivation were negligible. Anthropometry and body composition in KS is specific and dysmorphic and affected by AR CAG repeat length and decreased exposure to testosterone already during fetal life.

Time to stabilization in single leg drop jump landings: an examination of calculation methods and assessment of differences in sample rate, filter settings and trial length on outcome values.

PubMed

Fransz, Duncan P; Huurnink, Arnold; de Boode, Vosse A; Kingma, Idsart; van Dieën, Jaap H

2015-01-01

Time to stabilization (TTS) is the time it takes for an individual to return to a baseline or stable state following a jump or hop landing. A large variety exists in methods to calculate the TTS. These methods can be described based on four aspects: (1) the input signal used (vertical, anteroposterior, or mediolateral ground reaction force) (2) signal processing (smoothed by sequential averaging, a moving root-mean-square window, or fitting an unbounded third order polynomial), (3) the stable state (threshold), and (4) the definition of when the (processed) signal is considered stable. Furthermore, differences exist with regard to the sample rate, filter settings and trial length. Twenty-five healthy volunteers performed ten 'single leg drop jump landing' trials. For each trial, TTS was calculated according to 18 previously reported methods. Additionally, the effects of sample rate (1000, 500, 200 and 100 samples/s), filter settings (no filter, 40, 15 and 10 Hz), and trial length (20, 14, 10, 7, 5 and 3s) were assessed. The TTS values varied considerably across the calculation methods. The maximum effect of alterations in the processing settings, averaged over calculation methods, were 2.8% (SD 3.3%) for sample rate, 8.8% (SD 7.7%) for filter settings, and 100.5% (SD 100.9%) for trial length. Differences in TTS calculation methods are affected differently by sample rate, filter settings and trial length. The effects of differences in sample rate and filter settings are generally small, while trial length has a large effect on TTS values. Copyright © 2014 Elsevier B.V. All rights reserved.

Validation of a commercial inertial sensor system for spatiotemporal gait measurements in children.

PubMed

Lanovaz, Joel L; Oates, Alison R; Treen, Tanner T; Unger, Janelle; Musselman, Kristin E

2017-01-01

Although inertial sensor systems are becoming a popular tool for gait analysis in both healthy and pathological adult populations, there are currently no data on the validity of these systems for use with children. The purpose of this study was to validate spatiotemporal data from a commercial inertial sensor system (MobilityLab) in typically-developing children. Data from 10 children (5 males; 3.0-8.3 years, mean=5.1) were collected simultaneously from MobilityLab and 3D motion capture during gait at self-selected and fast walking speeds. Spatiotemporal parameters were compared between the two methods using a Bland-Altman method. The results indicate that, while the temporal gait measurements were similar between the two systems, MobilityLab demonstrated a consistent bias with respect to measurement of the spatial data (stride length). This error is likely due to differences in relative leg length and gait characteristics in children compared to the MobilityLab adult reference population used to develop the stride length algorithm. A regression-based equation was developed based on the current data to correct the MobilityLab stride length output. The correction was based on leg length, stride time, and shank range-of-motion, each of which were independently associated with stride length. Once the correction was applied, all of the spatiotemporal parameters evaluated showed good agreement. The results of this study indicate that MobilityLab is a valid tool for gait analysis in typically-developing children. Further research is needed to determine the efficacy of this system for use in children suffering from pathologies that impact gait mechanics. Copyright © 2016 Elsevier B.V. All rights reserved.

Volumetric Muscle Loss: Persistent Functional Deficits Beyond Frank Loss of Tissue

DTIC Science & Technology

2014-09-18

ing musculature5,6 that almost certainly changes the muscle’s architecture (e.g., fiber length to muscle length ratio) and composition (e.g...Vivo Isometric Functional Assessment TA muscle in vivo mechanical properties were measured in anesthetized rats (isoflurane 1.5–2.0%) in both legs as...testing system.5 Peak TA muscle isometric torque was determined with the ankle at a right angle 0˚ and 20˚ of dorsi- or plantar flexion, assuming a moment

Exercise intervention for unilateral amputees with low back pain: study protocol for a randomised, controlled trial.

PubMed

Wasser, Joseph G; Herman, Daniel C; Horodyski, MaryBeth; Zaremski, Jason L; Tripp, Brady; Page, Phillip; Vincent, Kevin R; Vincent, Heather K

2017-12-29

Atraumatic lower limb amputation is a life-changing event for approximately 185,000 persons in the United States each year. A unilateral amputation is associated with rapid changes to the musculoskeletal system including leg and back muscle atrophy, strength loss, gait asymmetries, differential mechanical joint loading and leg length discrepancies. Even with high-quality medical care and prostheses, amputees still develop secondary musculoskeletal conditions such as chronic low back pain (LBP). Resistance training interventions that focus on core stabilization, lumbar strength and dynamic stability during loading have strong potential to reduce LBP and address amputation-related changes to the musculoskeletal system. Home-based resistance exercise programs may be attractive to patients to minimize travel and financial burdens. This study will be a single-assessor-blinded, pre-post-test randomised controlled trial involving 40 men and women aged 18-60 years with traumatic, unilateral transtibial amputation. Participants will be randomised to a home-based, resistance exercise group (HBRX) or a wait-list control group (CON). The HBRX will consist of 12 weeks of elastic resistance band and bodyweight training to improve core and lumbopelvic strength. Participants will be monitored via Skype or Facetime on a weekly basis. The primary outcome will be pain severity (11-point Numerical Pain Rating Scale; NRS pain ). Secondary outcomes will include pain impact on quality of life (Medical Outcomes Short Form 36, Oswestry Disability Index and Roland Morris Disability Questionnaire), kinematics and kinetics of walking gait on an instrumented treadmill, muscle morphology (muscle thickness of multifidus, transversus abdominis, internal oblique), maximal muscle strength of key lumbar and core muscles, and daily step count. The study findings will determine whether a HBRX program can decrease pain severity and positively impact several physiological and mechanical factors that contribute to back pain in unilateral transtibial amputees with chronic LBP. We will determine the relative contribution of the exercise-induced changes in these factors on pain responsiveness in this population. ClinicalTrials.gov, ID: NCT03300375 . Registered on 2 October 2017.

Effect of Transducer Orientation on Errors in Ultrasound Image-Based Measurements of Human Medial Gastrocnemius Muscle Fascicle Length and Pennation

PubMed Central

Gandevia, Simon C.; Herbert, Robert D.

2016-01-01

Ultrasound imaging is often used to measure muscle fascicle lengths and pennation angles in human muscles in vivo. Theoretically the most accurate measurements are made when the transducer is oriented so that the image plane aligns with muscle fascicles and, for measurements of pennation, when the image plane also intersects the aponeuroses perpendicularly. However this orientation is difficult to achieve and usually there is some degree of misalignment. Here, we used simulated ultrasound images based on three-dimensional models of the human medial gastrocnemius, derived from magnetic resonance and diffusion tensor images, to describe the relationship between transducer orientation and measurement errors. With the transducer oriented perpendicular to the surface of the leg, the error in measurement of fascicle lengths was about 0.4 mm per degree of misalignment of the ultrasound image with the muscle fascicles. If the transducer is then tipped by 20°, the error increases to 1.1 mm per degree of misalignment. For a given degree of misalignment of muscle fascicles with the image plane, the smallest absolute error in fascicle length measurements occurs when the transducer is held perpendicular to the surface of the leg. Misalignment of the transducer with the fascicles may cause fascicle length measurements to be underestimated or overestimated. Contrary to widely held beliefs, it is shown that pennation angles are always overestimated if the image is not perpendicular to the aponeurosis, even when the image is perfectly aligned with the fascicles. An analytical explanation is provided for this finding. PMID:27294280

Effect of Transducer Orientation on Errors in Ultrasound Image-Based Measurements of Human Medial Gastrocnemius Muscle Fascicle Length and Pennation.

PubMed

Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

2016-01-01

Ultrasound imaging is often used to measure muscle fascicle lengths and pennation angles in human muscles in vivo. Theoretically the most accurate measurements are made when the transducer is oriented so that the image plane aligns with muscle fascicles and, for measurements of pennation, when the image plane also intersects the aponeuroses perpendicularly. However this orientation is difficult to achieve and usually there is some degree of misalignment. Here, we used simulated ultrasound images based on three-dimensional models of the human medial gastrocnemius, derived from magnetic resonance and diffusion tensor images, to describe the relationship between transducer orientation and measurement errors. With the transducer oriented perpendicular to the surface of the leg, the error in measurement of fascicle lengths was about 0.4 mm per degree of misalignment of the ultrasound image with the muscle fascicles. If the transducer is then tipped by 20°, the error increases to 1.1 mm per degree of misalignment. For a given degree of misalignment of muscle fascicles with the image plane, the smallest absolute error in fascicle length measurements occurs when the transducer is held perpendicular to the surface of the leg. Misalignment of the transducer with the fascicles may cause fascicle length measurements to be underestimated or overestimated. Contrary to widely held beliefs, it is shown that pennation angles are always overestimated if the image is not perpendicular to the aponeurosis, even when the image is perfectly aligned with the fascicles. An analytical explanation is provided for this finding.

Principles of appendage design in robots and animals determining terradynamic performance on flowable ground.

PubMed

Qian, Feifei; Zhang, Tingnan; Korff, Wyatt; Umbanhowar, Paul B; Full, Robert J; Goldman, Daniel I

2015-10-08

Natural substrates like sand, soil, leaf litter and snow vary widely in penetration resistance. To search for principles of appendage design in robots and animals that permit high performance on such flowable ground, we developed a ground control technique by which the penetration resistance of a dry granular substrate could be widely and rapidly varied. The approach was embodied in a device consisting of an air fluidized bed trackway in which a gentle upward flow of air through the granular material resulted in a decreased penetration resistance. As the volumetric air flow, Q, increased to the fluidization transition, the penetration resistance decreased to zero. Using a bio-inspired hexapedal robot as a physical model, we systematically studied how locomotor performance (average forward speed, v(x)) varied with ground penetration resistance and robot leg frequency. Average robot speed decreased with increasing Q, and decreased more rapidly for increasing leg frequency, ω. A universal scaling model revealed that the leg penetration ratio (foot pressure relative to penetration force per unit area per depth and leg length) determined v(x) for all ground penetration resistances and robot leg frequencies. To extend our result to include continuous variation of locomotor foot pressure, we used a resistive force theory based terradynamic approach to perform numerical simulations. The terradynamic model successfully predicted locomotor performance for low resistance granular states. Despite variation in morphology and gait, the performance of running lizards, geckos and crabs on flowable ground was also influenced by the leg penetration ratio. In summary, appendage designs which reduce foot pressure can passively maintain minimal leg penetration ratio as the ground weakens, and consequently permits maintenance of effective locomotion over a range of terradynamically challenging surfaces.

Superconducting cable cooling system by helium gas at two pressures

DOEpatents

Dean, John W.

1977-01-01

Thermally contacting, oppositely streaming, cryogenic fluid streams in the same enclosure in a closed cycle that changes the fluid from a cool high pressure helium gas to a cooler reduced pressure helium gas in an expander so as to be at different temperature ranges and pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid from a refrigerator at one end of the line as a cool gas at a temperature range T.sub.2 to T.sub.3 in the go leg, then circulating the gas through an expander at the other end of the line where the gas becomes a cooler gas at a reduced pressure and at a reduced temperature T.sub.4 and finally by circulating the cooler gas back again to the refrigerator in a return leg at a temperature range T.sub.4 to T.sub.5, while in thermal contact with the gas in the go leg, and in the same enclosure therewith for compression into a higher pressure gas at T.sub.2 in a closed cycle, where T.sub.2 >T.sub.3 and T.sub.5 >T.sub.4, the fluid leaves the enclosure in the go leg as a gas at its coldest point in the go leg, and the temperature distribution is such that the line temperature decreases along its length from the refrigerator due to the cooling from the gas in the return leg.

[Study of CT Automatic Exposure Control System (CT-AEC) Optimization in CT Angiography of Lower Extremity Artery by Considering Contrast-to-Noise Ratio].

PubMed

Inada, Satoshi; Masuda, Takanori; Maruyama, Naoya; Yamashita, Yukari; Sato, Tomoyasu; Imada, Naoyuki

2016-01-01

To evaluate the image quality and effect of radiation dose reduction by setting for computed tomography automatic exposure control system (CT-AEC) in computed tomographic angiography (CTA) of lower extremity artery. Two methods of setting were compared for CT-AEC [conventional and contrast-to-noise ratio (CNR) methods]. Conventional method was set noise index (NI): 14and tube current threshold: 10-750 mA. CNR method was set NI: 18, minimum tube current: (X+Y)/2 mA (X, Y: maximum X (Y)-axis tube current value of leg in NI: 14), and maximum tube current: 750 mA. The image quality was evaluated by CNR, and radiation dose reduction was evaluated by dose-length-product (DLP). In conventional method, mean CNRs for pelvis, femur, and leg were 19.9±4.8, 20.4±5.4, and 16.2±4.3, respectively. There was a significant difference between the CNRs of pelvis and leg (P<0.001), and between femur and leg (P<0.001). In CNR method, mean CNRs for pelvis, femur, and leg were 15.2±3.3, 15.3±3.2, and 15.3±3.1, respectively; no significant difference between pelvis, femur, and leg (P=0.973) in CNR method was observed. Mean DLPs were 1457±434 mGy⋅cm in conventional method, and 1049±434 mGy·cm in CNR method. There was a significant difference in the DLPs of conventional method and CNR method (P<0.001). CNR method gave equal CNRs for pelvis, femur, and leg, and was beneficial for radiation dose reduction in CTA of lower extremity artery.

Arm to leg coordination in elite butterfly swimmers.

PubMed

Chollet, D; Seifert, L; Boulesteix, L; Carter, M

2006-04-01

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

Biomechanical considerations in slipped capital femoral epiphysis and insights into prophylactic fixation.

PubMed

Leblanc, E; Bellemore, J M; Cheng, T; Little, D G; Birke, O

2017-04-01

Slipped capital femoral epiphysis (SCFE) is a deformity of the proximal femur secondary to widened and unstable physis. In stabilising the slip, gold standard treatments stop growth and involve premature physeal closure, which prevents the remodelling of the acquired deformity and creates a leg length discrepancy that may be significant in younger patients. We measured the impact of placing threaded screws across the proximal femoral physis by measuring the centre-trochanteric distance (CTD) and articulo-trochanteric distance (ATD) in participants with or without prophylactic fixation. We then compared the mechanical performance of static (stainless and titanium cannulated Synthes screws) and potentially growing implants (Synthes SCFE screw and Pega Medical Free Gliding screw) in a validated synthetic bone model. In the review of 30 non-fixed and 60 fixated hips over a mean follow-up of 1.9 years, we have noted a significant difference in pre/post CTD and ATD, as well as the change in CTD and ATD over time. In the biomechanical study, the newer implants allowing growth (Synthes SCFE screw and Pega Medical Free Gliding screw) were both shown to be at least non-inferior. The primary deformity of a SCFE in itself alters hip mechanics. Also, as confirmed in this study, there is a secondary deformity that is created by static fixation and relative trochanteric overgrowth. To help remodel mild deformities and prevent secondary trochanteric overgrowth, growing implants seem to be non-inferior to the more standard means of fixation in static testing.

Yellow lights : small changes in the timing of signal lights could reduce crashes at urban intersections

DOT National Transportation Integrated Search

2001-04-28

An Institute of Transportation Engineers (ITE) test at 122 standard four-leg intersections in Long Island, NY, shows that retiming the length of the yellow/red phases of traffic signals can reduce serious and reportable accidents ($1,000-plus damage ...

Effects of sensory augmentation on postural control and gait symmetry of transfemoral amputees: a case description.

PubMed

Pagel, Anna; Arieta, Alejandro Hernandez; Riener, Robert; Vallery, Heike

2016-10-01

Despite recent advances in leg prosthetics, transfemoral amputees still experience limitations in postural control and gait symmetry. It has been hypothesized that artificial sensory information might improve the integration of the prosthesis into the human sensory-motor control loops and, thus, reduce these limitations. In three transfemoral amputees, we investigated the effect of Electrotactile Moving Sensation for Sensory Augmentation (EMSSA) without training and present preliminary findings. Experimental conditions included standing with open/closed eyes on stable/unstable ground as well as treadmill walking. For standing conditions, spatiotemporal posturographic measures and sample entropy were derived from the center of pressure. For walking conditions, step length and stance duration were calculated. Conditions without feedback showed effects congruent with findings in the literature, e.g., asymmetric weight bearing and step length, and validated the collected data. During standing, with EMSSA a tendency to influence postural control in a negative way was found: Postural control was less effective and less efficient and the prosthetic leg was less involved. Sample entropy tended to decrease, suggesting that EMSSA demanded increased attention. During walking, with EMSSA no persistent positive effect was found. This contrasts the positive subjective assessment and the positive effect on one subject's step length.

Evaluation of function, performance, and preference as transfemoral amputees transition from mechanical to microprocessor control of the prosthetic knee.

PubMed

Hafner, Brian J; Willingham, Laura L; Buell, Noelle C; Allyn, Katheryn J; Smith, Douglas G

2007-02-01

To evaluate differences in function, performance, and preference between mechanical and microprocessor prosthetic knee control technologies. A-B-A-B reversal design. Home, community, and laboratory environments. Twenty-one unilateral, transfemoral amputees. Mechanical control prosthetic knee versus microprocessor control prosthetic knee (Otto Bock C-Leg). Stair rating, hill rating and time, obstacle course time, divided attention task accuracy and time, Amputee Mobility Predictor score, step activity, Prosthesis Evaluation Questionnaire score, Medical Outcomes Study 36-Item Short-Form Health Survey score, self-reported frequency of stumbles and falls, and self-reported concentration required for ambulation. Stair descent score, hill descent time, and hill sound-side step length showed significant (P<.01) improvement with the C-Leg. Users reported a significant (P<.05) decrease in frequency of stumbles and falls, frustration with falling, and difficulty in multitasking while using the microprocessor knee. Subject satisfaction with the C-Leg was significantly (P<.001) greater than the mechanical control prosthesis. The study population showed improved performance when negotiating stairs and hills, reduced frequency of stumbling and falling, and a preference for the microprocessor control C-Leg as compared with the mechanical control prosthetic knee.

Implementation of a piezoelectrically actuated self-contained quadruped robot

NASA Astrophysics Data System (ADS)

Ho, Thanhtam; Lee, Sangyoon

2009-05-01

In this paper we present the development of a mesoscale self-contained quadruped mobile robot that employs two pieces of piezoelectric actuators for the bounding gait locomotion, i.e., two rear legs have the same movement and two front legs do too. The actuator named LIPCA (LIghtweight Piezoceramic Composite curved Actuator) is a piezocomposite actuator that uses a PZT layer that is sandwiched between composite materials of carbon/epoxy and glass/epoxy layers to amplify the displacement. A biomimetic concept is applied to the design of the robot in a simplified way, such that each leg of the robot has only one degree of freedom. Considering that LIPCA requires a high input voltage and possesses capacitive characteristics, a small power supply circuit using PICO chips is designed for the implementation of selfcontained mobile robot. The prototype with the weight of 125 gram and the length of 120 mm can locomote with the bounding gait. Experiments showed that the robot can locomote at about 50 mm/sec with the circuit on board and the operation time is about 5 minutes, which can be considered as a meaningful progress toward the goal of building an autonomous legged robot actuated by piezoelectric actuators.

Dynamic traversal of large gaps by insects and legged robots reveals a template.

PubMed

Gart, Sean W; Yan, Changxin; Othayoth, Ratan; Ren, Zhiyi; Li, Chen

2018-02-02

It is well known that animals can use neural and sensory feedback via vision, tactile sensing, and echolocation to negotiate obstacles. Similarly, most robots use deliberate or reactive planning to avoid obstacles, which relies on prior knowledge or high-fidelity sensing of the environment. However, during dynamic locomotion in complex, novel, 3D terrains, such as a forest floor and building rubble, sensing and planning suffer bandwidth limitation and large noise and are sometimes even impossible. Here, we study rapid locomotion over a large gap-a simple, ubiquitous obstacle-to begin to discover the general principles of the dynamic traversal of large 3D obstacles. We challenged the discoid cockroach and an open-loop six-legged robot to traverse a large gap of varying length. Both the animal and the robot could dynamically traverse a gap as large as one body length by bridging the gap with its head, but traversal probability decreased with gap length. Based on these observations, we developed a template that accurately captured body dynamics and quantitatively predicted traversal performance. Our template revealed that a high approach speed, initial body pitch, and initial body pitch angular velocity facilitated dynamic traversal, and successfully predicted a new strategy for using body pitch control that increased the robot's maximal traversal gap length by 50%. Our study established the first template of dynamic locomotion beyond planar surfaces, and is an important step in expanding terradynamics into complex 3D terrains.

Sagittal plane bending moments acting on the lower leg during running.

PubMed

Haris Phuah, Affendi; Schache, Anthony G; Crossley, Kay M; Wrigley, Tim V; Creaby, Mark W

2010-02-01

Sagittal bending moments acting on the lower leg during running may play a role in tibial stress fracture development. The purpose of this study was to evaluate these moments at nine equidistant points along the length of the lower leg (10% point-90% point) during running. Kinematic and ground reaction force data were collected for 20 male runners, who each performed 10 running trials. Inverse dynamics and musculoskeletal modelling techniques were used to estimate sagittal bending moments due to reaction forces and muscle contraction. The muscle moment was typically positive during stance, except at the most proximal location (10% point) on the lower leg. The reaction moment was predominantly negative throughout stance and greater in magnitude than the muscle moment. Hence, the net sagittal bending moment acting on the lower leg was principally negative (indicating tensile loads on the posterior tibia). Peak moments typically occurred around mid-stance, and were greater in magnitude at the distal, compared with proximal, lower leg. For example, the peak reaction moment at the most distal point was -9.61+ or - 2.07%Bw.Ht., and -2.73 + or - 1.18%Bw.Ht. at the most proximal point. These data suggest that tensile loads on the posterior tibia are likely to be higher toward the distal end of the bone. This finding may explain the higher incidence of stress fracture in the distal aspect of the tibia, observed by some authors. Stress fracture susceptibility will also be influenced by bone strength and this should also be accounted for in future studies. Copyright 2009 Elsevier B.V. All rights reserved.

Crescent pyramid and drop-set systems do not promote greater strength gains, muscle hypertrophy, and changes on muscle architecture compared with traditional resistance training in well-trained men.

PubMed

Angleri, Vitor; Ugrinowitsch, Carlos; Libardi, Cleiton Augusto

2017-02-01

The aim of this study was to compare the effects of crescent pyramid (CP) and drop-set (DS) systems with traditional resistance training (TRAD) with equalized total training volume (TTV) on maximum dynamic strength (1-RM), muscle cross-sectional area (CSA), pennation angle (PA), and fascicle length (FL). Thirty-two volunteers had their legs randomized in a within-subject design in TRAD (3-5 sets of 6-12 repetitions at 75% 1-RM), CP (3-5 sets of 6-15 repetitions at 65-85% 1-RM), and DS (3-5 sets of ~50-75% 1-RM to muscle failure) protocols. Each leg was trained for 12 weeks. Participants had one leg fixed in the TRAD while the contralateral leg performed either CP or DS to allow for TTV equalization. The CSA increased significantly and similarly for all protocols (TRAD: 7.6%; CP: 7.5%; DS: 7.8%). All protocols showed significant and similar increases in leg press (TRAD = 25.9%; CP = 25.9%; DS = 24.9%) and leg extension 1-RM loads (TRAD = 16.6%; CP = 16.4%; DS = 17.1%). All protocols increased PA (TRAD = 10.6%; CP = 11.0%; DS = 10.3%) and FL (TRAD = 8.9%; CP = 8.9%; DS = 9.1%) similarly. CP and DS systems do not promote greater gains in strength, muscle hypertrophy and changes in muscle architecture compared to traditional resistance training.

Grounded running in quails: simulations indicate benefits of observed fixed aperture angle between legs before touch-down.

PubMed

Andrada, Emanuel; Rode, Christian; Blickhan, Reinhard

2013-10-21

Many birds use grounded running (running without aerial phases) in a wide range of speeds. Contrary to walking and running, numerical investigations of this gait based on the BSLIP (bipedal spring loaded inverted pendulum) template are rare. To obtain template related parameters of quails (e.g. leg stiffness) we used x-ray cinematography combined with ground reaction force measurements of quail grounded running. Interestingly, with speed the quails did not adjust the swing leg's angle of attack with respect to the ground but adapted the angle between legs (which we termed aperture angle), and fixed it about 30ms before touchdown. In simulations with the BSLIP we compared this swing leg alignment policy with the fixed angle of attack with respect to the ground typically used in the literature. We found symmetric periodic grounded running in a simply connected subset comprising one third of the investigated parameter space. The fixed aperture angle strategy revealed improved local stability and surprising tolerance with respect to large perturbations. Starting with the periodic solutions, after step-down step-up or step-up step-down perturbations of 10% leg rest length, in the vast majority of cases the bipedal SLIP could accomplish at least 50 steps to fall. The fixed angle of attack strategy was not feasible. We propose that, in small animals in particular, grounded running may be a common gait that allows highly compliant systems to exploit energy storage without the necessity of quick changes in the locomotor program when facing perturbations. © 2013 Elsevier Ltd. All rights reserved.

Light intensity of 5 or 20 lux on broiler behavior, welfare and productivity.

PubMed

Rault, Jean-Loup; Clark, Katie; Groves, Peter J; Cronin, Greg M

2017-04-01

Light intensity can influence broiler behavior, but discrepancies in the scientific literature remain. Furthermore, few studies have investigated the welfare implications induced by varying light intensity. We investigated the effects of providing 5 or 20 lux light intensity on broiler behavior, welfare and productivity. A total of 1,872 Ross 308 broilers of mixed sex were studied across 2 replicates. Treatments began on d 8 with one of 2 light intensity levels: 5 lux or 20 lux, using LED lights on a 16L:8D photoperiod with 30 min sunrise and sunset periods. Production data, behavioral activity, and plasma samples for corticosterone concentration analysis were collected weekly from 8 to 46 d of age. Eye weight was collected at 42 d of age. Leg strength was assessed at 35, 42 and 45 d of age using the latency to lie test and leg and foot conditions (foot pad dermatitis, hock burn, leg straightness) were assessed at 46 d. Live weight differed between light treatments, with broilers kept at 20 lux being lighter than broilers kept at 5 lux at 46 d of age (males: -5.1%, females: -2.8%, P < 0.0001), despite no significant differences in feed intake. However, broilers kept at 20 lux were more active during the photophase than broilers kept at 5 lux throughout the rearing period (P < 0.0001). Eye weight was also on average 5% lighter for broilers kept at 20 lux compared to 5 lux (P = 0.001). Nonetheless, there was no significant effect of light intensity on other measures of broiler welfare: mortality and culls, plasma corticosterone concentrations, or latency to lie reflective of leg strength. Hence, broilers kept at 20 lux compared to 5 lux were found to be more active, had slower growth, and had lighter eye weight, but other welfare measures reflective of biological functioning or leg health did not show significant changes. © 2016 Poultry Science Association Inc.

Reconciling extreme branch length differences: decoupling time and rate through the evolutionary history of filmy ferns.

PubMed

Schuettpelz, Eric; Pryer, Kathleen M

2006-06-01

The rate of molecular evolution is not constant across the Tree of Life. Characterizing rate discrepancies and evaluating the relative roles of time and rate along branches through the past are both critical to a full understanding of evolutionary history. In this study, we explore the interactions of time and rate in filmy ferns (Hymenophyllaceae), a lineage with extreme branch length differences between the two major clades. We test for the presence of significant rate discrepancies within and between these clades, and we separate time and rate across the filmy fern phylogeny to simultaneously yield an evolutionary time scale of filmy fern diversification and reconstructions of ancestral rates of molecular evolution. Our results indicate that the branch length disparity observed between the major lineages of filmy ferns is indeed due to a significant difference in molecular evolutionary rate. The estimation of divergence times reveals that the timing of crown group diversification was not concurrent for the two lineages, and the reconstruction of ancestral rates of molecular evolution points to a substantial rate deceleration in one of the clades. Further analysis suggests that this may be due to a genome-wide deceleration in the rate of nucleotide substitution.

A novel inverse association between cord 25-hydroxyvitamin D and leg length in boys up to three years. An Odense Child Cohort study.

PubMed

Christensen, Mathilde Egelund; Beck-Nielsen, Signe Sparre; Dalgård, Christine; Larsen, Søs Dragsbæk; Lykkedegn, Sine; Kyhl, Henriette Boye; Husby, Steffen; Christesen, Henrik Thybo

2018-01-01

Long standing vitamin D deficiency in children causes rickets with growth impairment. We investigated whether sub-ischial leg length (SLL) is shorter, and cephalo-caudal length:length (CCL:L) ratio and sitting height:height (SH:H) ratio larger, with lower cord s-25-hydroxyvitamin D (25OHD) in the population-based prospective Odense Child Cohort, Denmark. We included healthy singletons born to term with available measures of cord 25OHD and anthropometrics up to three years' age. Linear regression was stratified by sex a priori and adjusted for maternal ethnicity, pre-pregnancy body mass index and smoking during pregnancy, season of blood sampling and child age. Median (IQR) cord 25OHD was 48.0 (34.0-62.4) nmol/L. At mean age 19.1 months, n = 504, mean (SD) SLL was 31.7 (1.7) cm; CCL:L-ratio 0.62 (0.01). At 36.3 months, n = 956, mean SLL was 42.9 (2.0) cm; SH:H-ratio 0.56 (0.01). No participants had rickets. In adjusted analyses, 19-months-old boys had 0.1 cm shorter SLL (p = 0.009) and 0.1% higher CCL:L-ratio (p = 0.04) with every 10 nmol/L increase in cord 25OHD. Similar findings were seen for late pregnancy 25OHD. In the highest cord 25OHD quartile (>60.7 nmol/L), SLL was 0.8 cm shorter (95% C.I.: 1.36;-0.29, linear trend, p = 0.004), and CCL:L-ratio 0.8% higher (95% C.I. 8.0x10-05;0.01, linear trend, p = 0.01), compared to lowest quartile (<30.7 nmol/L). Similar associations with cord 25OHD were observed in 3-year-old boys. No consistent associations between 25OHD and anthropometrics were seen in girls at either age. No leg shortening was found with decreasing cord s-25OHD in a healthy population of infants. A small, yet significant inverse association between cord 25OHD and SLL in boys 1½-3 years warrants further investigations.

A k-omega multivariate beta PDF for supersonic turbulent combustion

NASA Technical Reports Server (NTRS)

Alexopoulos, G. A.; Baurle, R. A.; Hassan, H. A.

1993-01-01

In a recent attempt by the authors at predicting measurements in coaxial supersonic turbulent reacting mixing layers involving H2 and air, a number of discrepancies involving the concentrations and their variances were noted. The turbulence model employed was a one-equation model based on the turbulent kinetic energy. This required the specification of a length scale. In an attempt at detecting the cause of the discrepancy, a coupled k-omega joint probability density function (PDF) is employed in conjunction with a Navier-Stokes solver. The results show that improvements resulting from a k-omega model are quite modest.

Radiology of adolescent slipped capital femoral epiphysis: measurement of epiphyseal angles and diagnosis.

PubMed

Gekeler, Jörg

2007-10-01

AIMS OF DIAGNOSTIC RADIOGRAPHY: Visualization of the proximal femur in two clearly defined projections. Radiologic and morphological diagnosis of slipped capital femoral epiphysis. Evaluation of the stability of the femoral epiphysis: chronic slippage or acute interruption of continuity between the femoral epiphysis and the femoral neck metaphysis. Radiometric measurement of the spatial deformity of the femoral epiphysis. Measurement of the projected epiphyseal angle on the radiograph as the basis for possible conversion into anatomically correct angles at the proximal femur. Preoperative planning of therapeutic surgical procedures. Idiopathic hip pain in the growing child or adolescent. Referred pain to the knee or thigh. Unusual gait pattern with external rotation deformity of the leg, limping that favors one leg or limping due to leg length discrepancy. Abnormal sonography, CT or MRI findings. Eventful history including minor injury or genuine trauma. Symptoms and uncommon physical constitution: obesity, exceptional longitudinal growth of the extremities, and absence of secondary sex characteristics. Indications for Radiographic Imaging of the Hip Joint in Two Planes None. Standard positioning of the patient or the affected extremity. First standard radiograph: proximal femur in anteroposterior projection. Position of the leg with the patella directed anteriorly. Contraction of the external rotators at the hip joint is compensated by elevation of the hip until the leg is in the neutral position. Second standard radiograph: axial view of the proximal femur in anteroposterior projection. Leg flexed to 90 degrees at the hip and in 45 degrees abduction. Thigh position parallel to the longitudinal axis of the table (zero rotation). Early signs of incipient or imminent femoral epiphyseolysis: --Disintegration, widening and blurred margins of the epiphyseal plate. --Increasing loss of height of the femoral epiphysis due to incipient dislocation. --The tangent to the lateral femoral neck intersects only slightly with the femoral head or runs tangential to the epiphysis. --Important second radiograph in axial projection: incipient slippage is seen early here. Comparison with the contralateral side. Chronic slipped capital femoral epiphysis in adolescents: --Advanced epiphyseal dislocation visible in both planes. The tangent to the lateral femoral neck no longer intersects with the dislocated femoral epiphysis. In some cases, varus deformity of the femoral neck and periosteal elevation at the borders of the medial femoral neck. --Epiphyseal dislocation even more apparent in the axial view. Acute slipped capital femoral epiphysis in adolescents: --Complete interruption of continuity between epiphysis and metaphysis. --Widened gap between epiphysis and metaphysis. --Cystic irregularities of the metaphysis. --In most cases, substantial dislocation between epiphysis and metaphysis. --"Acute on chronic slip": specific type of acute epiphyseal dislocation subsequent to chronic epiphyseolysis. In addition to signs of acute separation, secondary symptoms of chronic epiphyseolysis such as femoral neck arcuation and spur formation at the head-neck junction. --Dynamic fluoroscopy may be indicated to confirm acute dislocation. Defined axes are marked on the radiograph: anatomic axis of the femur, femoral neck axis, and so-called epiphyseal axis (perpendicular to the base of the epiphysis). Measurement of the projected epiphysis-diaphysis angle (ED' angle) on the anteroposterior radiograph and the projected epiphyseal torsion angle (ET' angle) on the axial radiograph. For slight to moderate slippage, the difference between the epiphyseal dislocation angle obtained from the radiographs (as projected in two planes) compared with the anatomic, i.e., real dislocation angle at the proximal femur is generally relatively minor. Conversion of the projected angle to the real angle is not essential in these cases (if in doubt, see Table 1). For more severe dislocations, the differences between the projected and real angles are far more apparent. Table 1 facilitates conversion of the epiphyseal dislocation angles taken from the radiograph into anatomically correct dislocation angles at the proximal femur. Conversion to real angles, especially for preoperative planning of complex corrective surgery, is indicated for more severe deformities of the femoral epiphysis. Conversion into real (anatomic) angles is indicated for exact prognostic evaluation of prearthrotic deformities.

Comparative morphology of the prothoracic leg in heliconian butterflies: Tracing size allometry, podite fusions and losses in ontogeny and phylogeny.

PubMed

Moreira, Gilson R P; Silva, Denis S; Gonçalves, Gislene L

2017-07-01

Prothoracic legs of heliconian butterflies (Nymphalidae, Heliconiinae, Heliconiini) are reduced in size compared to mesothoracic and metathoracic legs. They have no apparent function in males, but are used by females for drumming on host plants, a behavior related to oviposition site selection. Here, taking into account all recognized lineages of heliconian butterflies, we described their tarsi using optical and scanning electron microscopy and searched for podite fusions and losses, and analyzed allometry at the static, ontogenetic and phylogenetic levels. Female tarsi were similar, club-shaped, showing from four to five tarsomeres, each bearing sensilla chaetica and trichodea. Male tarsi were cylindrical, formed from five (early diverging lineages) to one (descendant lineages) either partially or totally fused tarsomeres, all deprived of sensilla. Pretarsi were reduced in both sexes, in some species being either vestigial or absent. Tarsal lengths were smaller for males in almost all species. An abrupt decrease in size was detected for the prothoracic legs during molting to the last larval instar at both histological and morphometric levels. In both sexes, most allometric coefficients found at the population level for the prothoracic legs were negative compared to the mesothoracic leg and also to wings. Prothoracic tarsi decreased proportionally in size over evolutionary time; the largest and smallest values being found for nodes of the oldest and youngest lineages, respectively. Our results demonstrate that evolution of the prothoracic leg in heliconian butterflies has been based on losses and fusions of podites, in association with negative size allometry at static, ontogenetic and phylogenetic levels. These processes have been more pronounced in males. Our study provided further support to the hypothesis that evolution of these leg structures is driven by females, by changing their use from walking to drumming during oviposition site selection. In males the leg would have been selected against due to absence of function and thus progressively reduced in size, in association with podites fusions and lost. Copyright © 2017 Elsevier Ltd. All rights reserved.

A microdynamic version of the tensile test machine

NASA Technical Reports Server (NTRS)

Glaser, R. J.

1991-01-01

Very large space structures require structural reactions to control forces associated with nanometer-level displacements; JPL has accordingly built a tensile test machine capable of mN-level force measurements and nm-level displacement measurements, with a view to the study of structural linear joining technology at the lower limit of its resolution. The tester is composed of a moving table that is supported by six flexured legs and a test specimen cantilevered off the table to ground. Three vertical legs contain piezoactuators allowing changes in length up to 200 microns while generating axial load and bending moments. Displacements between ground and table are measured by means of three laser-interferometric channels.

Yellow-billed cuckoo in stomach of tiger shark

USGS Publications Warehouse

Saunders, G.B.; Clark, E.

1962-01-01

On 20 May 1961 an immature female tiger shark (Galeocerdo cuvier), 2.3 meters in length and weighing 52 kg, was caught in the Gulf of Mexico several miles offshore from Sarasota, Florida, by personnel of the Cape Haze Marine Laboratory. The contents of its stomach included a leg and some feathers of a land bird. The leg was sent to the Bird and Mammal Laboratories, Bureau of Sport Fisheries and Wildlife, Washington, D.C., where it was identified by Mrs. R. C. Laybourne as that of a Yellow-billed Cuckoo (Coccyzus americanus). In addition to this bird, the stomach contained a blue crab, several sea catfishes (Galeichthys felis), and part of a black nose shark (Carcharhinus acronatus).

The effect of waist twisting on walking speed of an amphibious salamander like robot

NASA Astrophysics Data System (ADS)

Yin, Xin-Yan; Jia, Li-Chao; Wang, Chen; Xie, Guang-Ming

2016-06-01

Amphibious salamanders often swing their waist to coordinate quadruped walking in order to improve their crawling speed. A robot with a swing waist joint, like an amphibious salamander, is used to mimic this locomotion. A control method is designed to allow the robot to maintain the rotational speed of its legs continuous and avoid impact between its legs and the ground. An analytical expression is established between the amplitude of the waist joint and the step length. Further, an optimization amplitude is obtained corresponding to the maximum stride. The simulation results based on automatic dynamic analysis of mechanical systems (ADAMS) and physical experiments verify the rationality and validity of this expression.

Stature estimation from body segment lengths in young adults--application to people with physical disabilities.

PubMed

Canda, Alicia

2009-03-01

Knowledge of stature is necessary for evaluating nutritional status and for correcting certain functional parameters. Measuring stature is difficult or impossible in bedridden or wheelchair-bound persons and may also be diminished by disorders of the spinal column or extremities. The purpose of this work is to develop estimation equations for young adult athletes for their subsequent application to disabled persons. The main sample comprised 445 male and 401 female sportspersons. Cross validation was also performed on 100 males and 101 females. All were Caucasian, the males being over 21 and the females over 18, and all practiced some kind of sport. The following variables were included: stature, sitting height, arm span, and lengths of upper arm, forearm, hand, thigh, lower leg, and foot. Simple and multiple regression analyses were performed using stature as a dependent variable and the others as predictive variables. The best equation for males (R(2)=0.978; RMSE=1.41 cm; PE=1.54 cm) was stature: 1.346+1.023 * lower leg+0.957 * sitting height+0.530 * thigh+0.493 * upper arm+0.228 * forearm. For females (R(2)=0.959; RMSE=1.57 cm; PE=1.25 cm) it was stature: 1.772+0.159 * arm span+0.957 * sitting height+0.424 * thigh+0.966 * lower leg. Alternative equations were developed for when a particular variable cannot be included for reasons of mobility, technical difficulty, or segment loss.

Biomechanical and energetic determinants of the walk-trot transition in horses.

PubMed

Griffin, Timothy M; Kram, Rodger; Wickler, Steven J; Hoyt, Donald F

2004-11-01

We studied nine adult horses spanning an eightfold range in body mass (M(b)) (90-720 kg) and a twofold range in leg length (L) (0.7-1.4 m). We measured the horses' walk-trot transition speeds using step-wise speed increments as they locomoted on a motorized treadmill. We then measured their rates of oxygen consumption over a wide range of walking and trotting speeds. We interpreted the transition speed results using a simple inverted-pendulum model of walking in which gravity provides the centripetal force necessary to keep the leg in contact with the ground. By studying a large size range of horses, we were naturally able to vary the absolute walking speed that would produce the same ratio of centripetal to gravitational forces. This ratio, (M(b)v2/L)/(M(b)g), reduces to the dimensionless Froude number (v2/gL), where v is forward speed, L is leg length and g is gravitational acceleration. We found that the absolute walk-trot transition speed increased with size from 1.6 to 2.3 m s(-1), but it occurred at nearly the same Froude number (0.35). In addition, horses spontaneously switched between gaits in a narrow range of speeds that corresponded to the metabolically optimal transition speed. These results support the hypotheses that the walk-trot transition is triggered by inverted-pendulum dynamics and occurs at the speed that maximizes metabolic economy.

Pirogow's Amputation: A Modification of the Operation Method

PubMed Central

Bueschges, M.; Muehlberger, T.; Mauss, K. L.; Bruck, J. C.; Ottomann, C.

2013-01-01

Introduction. Pirogow's amputation at the ankle presents a valuable alternative to lower leg amputation for patients with the corresponding indications. Although this method offers the ability to stay mobile without the use of a prosthesis, it is rarely performed. This paper proposes a modification regarding the operation method of the Pirogow amputation. The results of the modified operation method on ten patients were objectified 12 months after the operation using a patient questionnaire (Ankle Score). Material and Methods. We modified the original method by rotating the calcaneus. To fix the calcaneus to the tibia, Kirschner wire and a 3/0 spongiosa tension screw as well as a Fixateur externe were used. Results. 70% of those questioned who were amputated following the modified Pirogow method indicated an excellent or very good result in total points whereas in the control group (original Pirogow's amputation) only 40% reported excellent or very good result. In addition, the level of pain experienced one year after the completed operation showed different results in favour of the group being operated with the modified way. Furthermore, patients in both groups showed differences in radiological results, postoperative leg length difference, and postoperative mobility. Conclusion. The modified Pirogow amputation presents a valuable alternative to the original amputation method for patients with the corresponding indications. The benefits are found in the significantly reduced pain, difference in reduced radiological complications, the increase in mobility without a prosthesis, and the reduction of postoperative leg length difference. PMID:23606976

Report: Congressionally Requested Information on the Status and Length of Review for Appalachian Surface Mining Permit Applications

EPA Pesticide Factsheets

Report #12-P-0083, November 21, 2011. After reconciling discrepancies and vetting information, we identified 185 surface mining permit applications to review from the list of 237 that we received from the senator.

Percutaneous Image-Guided Aspiration and Sclerosis of Adventitial Cystic Disease of the Femoral Vein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Jason M.; Kiankhooy, Armin; Bertges, Daniel J.

2009-07-15

Adventitial cystic disease (ACD), also known as cystic mucoid or myxomatous degeneration, is a rare vascular disease mainly seen in arteries. Seventeen cases have been reported in the world literature. We report the first known case of ACD successfully treated with percutaneous image-guided ethanol sclerosis. Computed tomography showed a cystic mass adherent to the wall of the common femoral vein. An ultrasound examination revealed a deep venous thrombosis of the leg, secondary to extrinsic compression of the common femoral vein. Three years prior to our procedure, the cyst was aspirated, which partially relieved the patient's symptoms. Over the following 3more » years the patient's symptoms worsened and a 10-cm discrepancy in thigh size developed, in addition to the deep venous thrombosis associated with lower-extremity edema. Using ultrasound guidance and fluoroscopic control, the cyst was drained and then sclerosed with absolute ethanol. The patient's symptoms and leg swelling resolved completely within several weeks. Follow-up physical examination and duplex ultrasound 6 months following sclerosis demonstrated resolution of the symptoms and elimination of the extrinsic compression effect of the ACD on the common femoral vein.« less

A Novel Perforator Flap Training Model Using a Chicken Leg

PubMed Central

Cifuentes, Ignacio J.; Yañez, Ricardo A.; Salisbury, Maria C.; Rodriguez, José R.; Varas, Julian E.; Dagnino, Bruno L.

2016-01-01

Introduction  Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. Methods  A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. Results  The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. Conclusion  This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training. PMID:27616823

Developmental Study on Leg-to-Body Ratio Preferences.

PubMed

Sabiniewicz, Agnieszka; Sorokowska, Agnieszka; Oleszkiewicz, Anna; Sorokowski, Piotr

2015-09-01

Few studies have tested developmental differences in the perception of human body attractiveness and none have investigated development of Leg-to-Body Ratio (LBR) preferences. The aim of the current study was to determine whether preferences for LBR are largely innate and present among children in their early childhood, acquired in the course of socialization, and/or triggered by biological and hormonal changes. The study included 450 Polish men and women from Lower Silesia and Opole Province, Poland, whose ages ranged from 3 to 20 years. Participants were asked to choose which figurine they found the most attractive from a set of male and female figurines of various LBRs. We found that children below 8 years of age did not prefer any particular LBR and starting from about 9 years of age, preferences towards the legs of average length emerged. Importantly an LBR higher than the population average was not perceived as the most attractive until the age of 15 years. Therefore, we have empirically confirmed that LBR preferences change during develop ment.

A bipedal DNA Brownian motor with coordinated legs.

PubMed

Omabegho, Tosan; Sha, Ruojie; Seeman, Nadrian C

2009-04-03

A substantial challenge in engineering molecular motors is designing mechanisms to coordinate the motion between multiple domains of the motor so as to bias random thermal motion. For bipedal motors, this challenge takes the form of coordinating the movement of the biped's legs so that they can move in a synchronized fashion. To address this problem, we have constructed an autonomous DNA bipedal walker that coordinates the action of its two legs by cyclically catalyzing the hybridization of metastable DNA fuel strands. This process leads to a chemically ratcheted walk along a directionally polar DNA track. By covalently cross-linking aliquots of the walker to its track in successive walking states, we demonstrate that this Brownian motor can complete a full walking cycle on a track whose length could be extended for longer walks. We believe that this study helps to uncover principles behind the design of unidirectional devices that can function without intervention. This device should be able to fulfill roles that entail the performance of useful mechanical work on the nanometer scale.

Venous interruption for pulmonary embolism: the illustrative case of Richard M. Nixon.

PubMed

Barker, W F; Hickman, E B; Harper, J A; Lungren, J

1997-07-01

This politically prominent patient was seen in consultation on October 26, 1974 because of chronic venous thrombosis and a recent pulmonary embolism. His problems had begun in 1965 when he developed venous thrombosis in the left leg after a length trip by air. His treatment had been sporadic and his compliance with treatment less than satisfactory. Because of detailed phlebography demonstrating (1) no clots in the veins of the right leg, (2) extensive loose lying clot filling the superficial, deep, and external iliac veins on the left, and (3) because of prior difficulties with patient compliance unilateral interruption of the left external iliac vein above the top of the clot was proposed. Despite some postoperative complications, the patient made a full recovery and lived 19 years on warfarin therapy before death from unrelated causes. He suffered no significant edema or other postphlebitic symptoms in the affected leg. The history of the use of venous interruption under these circumstances is reviewed to justify the operation that was performed.

Heat Transfer and Geometrical Analysis of Thermoelectric Converters Driven by Concentrated Solar Radiation

PubMed Central

Suter, Clemens; Tomeš, Petr; Weidenkaff, Anke; Steinfeld, Aldo

2010-01-01

A heat transfer model that couples radiation/conduction/convection heat transfer with electrical potential distribution is developed for a thermoelectric converter (TEC) subjected to concentrated solar radiation. The 4-leg TEC module consists of two pairs of p-type La1.98Sr0.02CuO4 and n-type CaMn0.98Nb0.02O3 legs that are sandwiched between two ceramic Al2O3 hot/cold plates and connected electrically in series and thermally in parallel. The governing equations for heat transfer and electrical potential are formulated, discretized and solved numerically by applying the finite volume (FV) method. The model is validated in terms of experimentally measured temperatures and voltages/power using a set of TEC demonstrator modules, subjected to a peak radiative flux intensity of 300 suns. The heat transfer model is then applied to examine the effect of the geometrical parameters (e.g. length/width of legs) on the solar-to-electricity energy conversion efficiency.

Geospatial Analysis and Model Evaluation Software (GAMES): Integrated Web-Based Analysis and Visualization

DTIC Science & Technology

2014-04-11

particle location files for each source (hours) dti : time step in seconds horzmix: CONSTANT = use the value of horcon...however, if leg lengths are short. Extreme values of D/Lo can occur. We will handle these by assigning a maximum to the output. This is discussed by

A Kinematic Analysis of the Jumping Front-Leg Axe-Kick in Taekwondo

PubMed Central

Preuschl, Emanuel; Hassmann, Michaela; Baca, Arnold

2016-01-01

The jumping front-leg axe-kick is a valid attacking and counterattacking technique in Taekwondo competition (Streif, 1993). Yet, the existing literature on this technique is sparse (Kloiber et al., 2009). Therefore, the goal of this study was to determine parameters contributing significantly to maximum linear speed of the foot at impact. Parameters are timing of segment and joint angular velocity characteristics and segment lengths of the kicking leg. Moreover, we were interested in the prevalence of proximal-to-distal-sequencing. Three-dimensional kinematics of the kicks of 22 male Taekwondo-athletes (age: 23.3 ± 5.3 years) were recorded via a motion capturing system (Vicon Motion Systems Limited, Oxford, UK). The participants performed maximum effort kicks onto a rack-held kicking pad. Only the kick with the highest impact velocity was analysed, as it was assumed to represent the individual’s best performance. Significant Pearson correlations to impact velocity were found for pelvis tilt angular displacement (r = 0.468, p < 0.05) and for hip extension angular velocity (r = -0.446, p < 0.05) and for the timing of the minima of pelvis tilt velocity (r = -0.426, p < 0.05) and knee flexion velocity (r = -0.480, p < 0.05). Backward step linear regression analysis suggests a model consisting of three predictor variables: pelvis tilt angular displacement, hip flexion velocity at target contact and timing of pelvic tilt angular velocity minimum (adjusted R2 = 0.524). Results of Chi-Squared tests show that neither for the leg-raising period (χ2 = 2.909) of the technique, nor for the leg-lowering period a pattern of proximal-to-distal sequencing is prevalent (χ2 = 0.727). From the results we conclude that the jumping front-leg axe-kick does not follow a proximal-to-distal pattern. Raising the leg early in the technique and apprehending the upper body to be leant back during the leg-lowering period seems to be beneficial for high impact velocity. Furthermore, striking by extending the hip rather than by flexing the knee could raise impact velocity. Key points Angular velocity characteristics of the pelvis segment and the kicking leg’s hip and knee joint show no proximal-to-distal sequencing, neither for the leg-raising or leg-lowering period in a jumping front-leg axe-kick. Anthropometric parameters of taekwondo athlete’s do not influence their impact velocities. In order to raise the impact velocity in the jumping front-leg axe-kick an athlete should avoid tilting back with the torso. Instead, an upright position should be maintained. In the leg-lowering period, we suggest hitting the target by using hip extension with a rather straight knee, instead of flexing the knee. PMID:26957931

People bouncing on trampolines: dramatic energy transfer, a table-top demonstration, complex dynamics and a zero sum game.

PubMed

Srinivasan, Manoj; Wang, Yang; Sheets, Alison

2013-01-01

Jumping on trampolines is a popular backyard recreation. In some trampoline games (e.g., "seat drop war"), when two people land on the trampoline with only a small time-lag, one person bounces much higher than the other, as if energy has been transferred from one to the other. First, we illustrate this energy-transfer in a table-top demonstration, consisting of two balls dropped onto a mini-trampoline, landing almost simultaneously, sometimes resulting in one ball bouncing much higher than the other. Next, using a simple mathematical model of two masses bouncing passively on a massless trampoline with no dissipation, we show that with specific landing conditions, it is possible to transfer all the kinetic energy of one mass to the other through the trampoline - in a single bounce. For human-like parameters, starting with equal energy, the energy transfer is maximal when one person lands approximately when the other is at the bottom of her bounce. The energy transfer persists even for very stiff surfaces. The energy-conservative mathematical model exhibits complex non-periodic long-term motions. To complement this passive bouncing model, we also performed a game-theoretic analysis, appropriate when both players are acting strategically to steal the other player's energy. We consider a zero-sum game in which each player's goal is to gain the other player's kinetic energy during a single bounce, by extending her leg during flight. For high initial energy and a symmetric situation, the best strategy for both subjects (minimax strategy and Nash equilibrium) is to use the shortest available leg length and not extend their legs. On the other hand, an asymmetry in initial heights allows the player with more energy to gain even more energy in the next bounce. Thus synchronous bouncing unstable is unstable both for passive bouncing and when leg lengths are controlled as in game-theoretic equilibria.

People Bouncing on Trampolines: Dramatic Energy Transfer, a Table-Top Demonstration, Complex Dynamics and a Zero Sum Game

PubMed Central

Srinivasan, Manoj; Wang, Yang; Sheets, Alison

2013-01-01

Jumping on trampolines is a popular backyard recreation. In some trampoline games (e.g., “seat drop war”), when two people land on the trampoline with only a small time-lag, one person bounces much higher than the other, as if energy has been transferred from one to the other. First, we illustrate this energy-transfer in a table-top demonstration, consisting of two balls dropped onto a mini-trampoline, landing almost simultaneously, sometimes resulting in one ball bouncing much higher than the other. Next, using a simple mathematical model of two masses bouncing passively on a massless trampoline with no dissipation, we show that with specific landing conditions, it is possible to transfer all the kinetic energy of one mass to the other through the trampoline – in a single bounce. For human-like parameters, starting with equal energy, the energy transfer is maximal when one person lands approximately when the other is at the bottom of her bounce. The energy transfer persists even for very stiff surfaces. The energy-conservative mathematical model exhibits complex non-periodic long-term motions. To complement this passive bouncing model, we also performed a game-theoretic analysis, appropriate when both players are acting strategically to steal the other player's energy. We consider a zero-sum game in which each player's goal is to gain the other player's kinetic energy during a single bounce, by extending her leg during flight. For high initial energy and a symmetric situation, the best strategy for both subjects (minimax strategy and Nash equilibrium) is to use the shortest available leg length and not extend their legs. On the other hand, an asymmetry in initial heights allows the player with more energy to gain even more energy in the next bounce. Thus synchronous bouncing unstable is unstable both for passive bouncing and when leg lengths are controlled as in game-theoretic equilibria. PMID:24236029

A new species of pine anole from the Sierra Madre del Sur in Oaxaca, Mexico (Reptilia, Squamata, Dactyloidae: Anolis).

PubMed

Köhler, Gunther; Pérez, Raúl Gómez Trejo; Petersen, Claus Bo P; de La Cruz, Fausto R Mendez

2014-01-09

We describe the new species Anolis peucephilus sp. nov. from the Pacific versant of southern Mexico. Anolis peucephilus differs from all congeners by having a combination of (1) smooth ventral scales; (2) usually a patch of three greatly enlarged supraocular scales; (3) extremely short hind legs, longest toe of adpressed hind leg reaching to a point between levels of axilla and ear opening, ratio shank length/snout-vent length 0.18-0.21; (4) circumnasal usually in contact with first supralabial; and (5) a large yellowish orange dewlap in males and a very small to small white dewlap in females. In external morphology, A. peucephilus is most similar to A. omiltemanus from which it differs by having even shorter hind legs with the longest toe of adpressed hind leg reaching to a point between levels of axilla and ear opening (versus usually to ear opening, occasionally to slightly beyond ear opening or to a point between shoulder and ear opening in A. omiltemanus), a slightly larger dewlap in females, to 64 mm2 (versus to 41 mm2 in A. omiltemanus), the circumnasal usually in contact with the first supralabial (versus those scales separated by the presence of a subnasal in A. omiltemanus), and 4-6 internasal scales in the new species (versus usually 6-7 in A. omiltemanus). Furthermore, A. peucephilus differs from A. omiltemanus in hemipenial morphology (no finger-like processus on asulcate side in A. peucephilus versus such a processus present in A. omiltemanus). Also, in a preliminary molecular genetic analysis of the mitochondrial CO1 gene fragment, A. peucephilus has a genetic distance of 11.5% from A. omiltemanus. Anolis peucephilus was collected at night while the lizards were sleeping in pine trees, 2-10 m above the ground.

Magnetic resonance imaging findings of the lumbar spine in elite horseback riders: correlations with back pain, body mass index, trunk/leg-length coefficient, and riding discipline.

PubMed

Kraft, Clayton N; Pennekamp, Peter H; Becker, Ute; Young, Mei; Diedrich, Oliver; Lüring, Christian; von Falkenhausen, Makus

2009-11-01

Most orthopaedic problems experienced by competitive horseback riders are related to pain in the lower back, hip joint, and hamstring muscles. Riders-especially, show jumpers-are frequently hampered in their performance because of lumbar pain. To date, there has been no research into lumbar disk degeneration in elite competitive riders. Competitive horseback riding accelerates lumbar disk degeneration. Cross-sectional study; Level of evidence, 3. Fifty-eight elite riders (18 men, 40 women; mean age, 32.4 years) and a control group of 30 nonriding volunteers (17 men, 13 women; mean age, 28.7 years) were evaluated for lumbar disk degeneration, cross-sectional area of paraspinal muscles, spondylolysis, and spondylolisthesis, using magnetic resonance imaging (MRI). The prevalence of disk degeneration between the 2 groups was compared, and the relationship was investigated between low back pain (LBP), riding discipline, body mass index (BMI), trunk/leg-length coefficient, and MRI results. Eighty-eight percent of elite riders (n = 51) had a history of LBP, versus 33% of the controls (P < .05). There was no statistical difference for the prevalence of LBP among the different riding disciplines. However, there was a high rate of pathologic T2 signal intensity of the lumbar intervertebral disk among riders-specifically, dressage riders-yet no significant increase when compared with controls. History of LBP symptoms, riding discipline, BMI, and trunk/leg-length ratio had no significant effect on the development of lumbar disk degeneration. Occult fractures of the pars interarticularis and manifest spondylolysis were not seen for any rider. Two controls had spondylolisthesis Meyerding grade 1 not associated with back pain. Although riders have a high prevalence of LBP, there is no conclusive MRI evidence to suggest that the cause lies in undue disk degeneration, spondylolysis, spondylolisthesis, or pathologic changes of the paraspinal muscles of the lumbar spine.

Validity of total and segmental impedance measurements for prediction of body composition across ethnic population groups.

PubMed

Deurenberg, P; Deurenberg-Yap, M; Schouten, F J M

2002-03-01

To test the impact of body build factors on the validity of impedance-based body composition predictions across (ethnic) population groups and to study the suitability of segmental impedance measurements. Cross-sectional observational study. Ministry of Health and School of Physical Education, Nanyang Technological University, Singapore. A total of 291 female and male Chinese, Malays and Indian Singaporeans, aged 18-69, body mass index (BMI) 16.0-40.2 kg/ m2. Anthropometric parameters were measured in addition to impedance (100 kHz) of the total body, arms and legs. Impedance indexes were calculated as height2/impedance. Arm length (span) and leg length (sitting height), wrist and knee width were measured from which body build indices were calculated. Total body water (TBW) was measured using deuterium oxide dilution. Extra cellular water (ECW) was measured using bromide dilution. Body fat percentage was determined using a chemical four-compartment model. The bias of TBW predicted from total body impedance index (bias: measured minus predicted TBW) was different among the three ethnic groups, TBW being significantly underestimated in Indians compared to Chinese and Malays. This bias was found to be dependent on body water distribution (ECW/TBW) and parameters of body build, mainly relative (to height) arm length. After correcting for differences in body water distribution and body build parameters the differences in bias across the ethnic groups disappeared. The impedance index using total body impedance was better correlated with TBW than the impedance index of arm or leg impedance, even after corrections for body build parameters. The study shows that ethnic-specific bias of impedance-based prediction formulas for body composition is due mainly to differences in body build among the ethnic groups. This means that the use of 'general' prediction equations across different (ethnic) population groups without prior testing of their validity should be avoided. Total body impedance has higher predictive value than segmental impedance.

Patterns of Growth after Kidney Transplantation among Children with ESRD

PubMed Central

Franke, Doris; Thomas, Lena; Steffens, Rena; Pavičić, Leo; Gellermann, Jutta; Froede, Kerstin; Querfeld, Uwe; Haffner, Dieter

2015-01-01

Background and objectives Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study. Design, setting, participants, & measurements Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2–18 years with a median follow-up of 3.4 years (interquartile range, 1.9–5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments. Results During early childhood, patients showed lower mean SD scores (SDS) for height (−1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2–4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05). Conclusions Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome. PMID:25352379

Patterns of growth after kidney transplantation among children with ESRD.

PubMed

Franke, Doris; Thomas, Lena; Steffens, Rena; Pavičić, Leo; Gellermann, Jutta; Froede, Kerstin; Querfeld, Uwe; Haffner, Dieter; Živičnjak, Miroslav

2015-01-07

Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study. Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2-18 years with a median follow-up of 3.4 years (interquartile range, 1.9-5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments. During early childhood, patients showed lower mean SD scores (SDS) for height (-1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2-4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05). Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome. Copyright © 2015 by the American Society of Nephrology.

Fabrication of Pop-up Detector Arrays on Si Wafers

NASA Technical Reports Server (NTRS)

Li, Mary J.; Allen, Christine A.; Gordon, Scott A.; Kuhn, Jonathan L.; Mott, David B.; Stahle, Caroline K.; Wang, Liqin L.

1999-01-01

High sensitivity is a basic requirement for a new generation of thermal detectors. To meet the requirement, close-packed, two-dimensional silicon detector arrays have been developed in NASA Goddard Space Flight Center. The goal of the task is to fabricate detector arrays configured with thermal detectors such as infrared bolometers and x-ray calorimeters to use in space fliGht missions. This paper focuses on the fabrication and the mechanical testing of detector arrays in a 0.2 mm pixel size, the smallest pop-up detectors being developed so far. These array structures, nicknamed "PUDS" for "Pop-Up Detectors", are fabricated on I pm thick, single-crystal, silicon membranes. Their designs have been refined so we can utilize the flexibility of thin silicon films by actually folding the silicon membranes to 90 degrees in order to obtain close-packed two-dimensional arrays. The PUD elements consist of a detector platform and two legs for mechanical support while also serving as electrical and thermal paths. Torsion bars and cantilevers connecting the detector platform to the legs provide additional flexures for strain relief. Using micro-electromechanical structure (MEMS) fabrication techniques, including photolithography, anisotropic chemical etching, reactive-ion etching, and laser dicing, we have fabricated PLTD detector arrays of fourteen designs with a variation of four parameters including cantilever length, torsion bar length and width, and leg length. Folding tests were conducted to test mechanical stress distribution for the array structures. We obtained folding yields and selected optimum design parameters to reach minimal stress levels. Computer simulation was also employed to verify mechanical behaviors of PUDs in the folding process. In addition, scanning electron microscopy was utilized to examine the flatness of detectors and the alignment of detector pixels in arrays. The fabrication of thermistors and heaters on the pop-up detectors is under way, preparing us for the next step of the experiment, the thermal test.

Effect of selection for growth rate on relative growth in rabbits.

PubMed

Pascual, M; Pla, M; Blasco, A

2008-12-01

The effect of selection for growth rate on relative growth of the rabbit body components was studied. Animals from the 18th generation of a line selected for growth rate were compared with a contemporary control group formed with offspring of embryos that were frozen at the seventh generation of selection of the same line. A total of 313 animals were slaughtered at 4, 9, 13, 20, and 40 wk old. The offal, organs, tissues, and retail cuts were weighed, and several carcass linear measurements were recorded. Huxley's allometric equations relating the weights of the components with respect to BW were fitted. Butterfield's quadratic equations relating the degree of maturity of the components and the degree of maturity of BW were also fitted. In most of the components studied, both models lead to similar patterns of growth. Blood was isometric or early maturing and skin was late maturing or isometric depending on the use of Huxley's or Butterfield's model. Full gastrointestinal tract, liver, kidneys, thoracic viscera, and head were early maturing, and the chilled carcass and reference carcass were late maturing. The retail cuts of the reference carcass showed isometry (forelegs) or late maturing growth (breast and ribs, loin, hind legs, and abdominal walls). Dissectible fat of the carcass and meat of the hind leg had a late development, whereas bone of the hind leg was early maturing. Lumbar circumference length was later maturing than the carcass length and thigh length. Sex did not affect the relative growth of most of the components. Butterfield's model showed that males had an earlier development of full gastrointestinal tract and later growth of kidneys than females. No effect of selection on the relative growth of any of the components studied was found, leading to similar patterns of growth and similar carcass composition at a given degree of maturity after 11 generations of selection for growth rate.

Interstitial water studies on small core samples, Deep Sea Drilling Project, Leg 5

USGS Publications Warehouse

Manheim, F. T.; Chan, K.M.; Sayles, F.L.

1970-01-01

Leg 5 samples fall into two categories with respect to interstitial water composition: 1) rapidly deposited terrigenous or appreciably terrigenous deposits, such as in Hole 35 (western Escanaba trough, off Cape Mendocino, California); and, 2) slowly deposited pelagic clays and biogenic muds and oozes. Interstitial waters in the former show modest to slight variations in chloride and sodium, but drastic changes in non-conservative ions such as magnesium and sulfate. The pelagic deposits show only relatively minor changes in both conservative and non-conservative pore fluid constituents. As was pointed out in earlier Leg Reports, it is believed that much of the variation in chloride in pore fluids within individual holes is attributable to the manipulation of samples on board ship and in the laboratory. On the other hand, the scatter in sodium is due in part to analytical error (on the order of 2 to 3 per cent, in terms of a standard deviation), and it probably accounts for most of the discrepancies in total anion and cation balance. All constituents reported here, with the exception of bulk water content, were analyzed on water samples which were sealed in plastic tubes aboard ship and were subsequently opened and divided into weighed aliquots in the laboratory. Analytical methods follow the atomic absorption, wet chemical and emission spectrochemical techniques briefly summarized in previous reports, e.g. Manheim et al., 1969, and Chan and Manheim, 1970. The authors acknowledge assistance from W. Sunda, D. Kerr, C. Lawson and H. Richards, and thank D. Spencer, P. Brewer and E. Degens for allowing the use of equipment and laboratory facilities.

Floating seal system for rotary devices

DOEpatents

Banasiuk, Hubert A.

1983-01-01

This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10.degree. to about 30.degree. in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device.

Floating seal system for rotary devices

DOEpatents

Banasiuk, H.A.

1983-08-23

This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.

Sprint running: how changes in step frequency affect running mechanics and leg spring behaviour at maximal speed.

PubMed

Monte, Andrea; Muollo, Valentina; Nardello, Francesca; Zamparo, Paola

2017-02-01

The purpose of this study was to investigate the changes in selected biomechanical variables in 80-m maximal sprint runs while imposing changes in step frequency (SF) and to investigate if these adaptations differ based on gender and training level. A total of 40 athletes (10 elite men and 10 women, 10 intermediate men and 10 women) participated in this study; they were requested to perform 5 trials at maximal running speed (RS): at the self-selected frequency (SF s ) and at SF ±15% and ±30%SF s . Contact time (CT) and flight time (FT) as well as step length (SL) decreased with increasing SF, while k vert increased with it. At SF s , k leg was the lowest (a 20% decrease at ±30%SF s ), while RS was the largest (a 12% decrease at ±30%SF s ). Only small changes (1.5%) in maximal vertical force (F max ) were observed as a function of SF, but maximum leg spring compression (ΔL) was largest at SF s and decreased by about 25% at ±30%SF s . Significant differences in F max , Δy, k leg and k vert were observed as a function of skill and gender (P < 0.001). Our results indicate that RS is optimised at SF s and that, while k vert follows the changes in SF, k leg is lowest at SF s .

Acute Effects of Stretching on Leg and Vertical Stiffness During Treadmill Running.

PubMed

Pappas, Panagiotis T; Paradisis, Giorgos P; Exell, Timothy A; Smirniotou, Athanasia S; Tsolakis, Charilaos K; Arampatzis, Adamantios

2017-12-01

Pappas, PT, Paradisis, GP, Exell, TA, Smirniotou, AS, Tsolakis, CK, and Arampatzis, A. Acute effects of stretching on leg and vertical stiffness during treadmill running. J Strength Cond Res 31(12): 3417-3424, 2017-The implementation of static (SS) and dynamic (DS) stretching during warm-up routines produces significant changes in biological and functional properties of the human musculoskeletal system. These properties could affect the leg and vertical stiffness characteristics that are considered important factors for the success of athletic activities. The aim of this study was to investigate the influence of SS and DS on selected kinematic variables, and leg and vertical stiffness during treadmill running. Fourteen men (age: 22.58 ± 1.05 years, height: 1.77 ± 0.05 m, body mass: 72.74 ± 10.04 kg) performed 30-second running bouts at 4.44 m·s, under 3 different stretching conditions (SS, DS, and no stretching). The total duration in each stretching condition was 6 minutes, and each of the 4 muscle groups was stretched for 40 seconds. Leg and vertical stiffness values were calculated using the "sine wave" method, with no significant differences in stiffness found between stretching conditions. After DS, vertical ground reaction force increased by 1.7% (p < 0.05), which resulted in significant (p < 0.05) increases in flight time (5.8%), step length (2.2%), and vertical displacement of the center of mass (4.5%) and a decrease in step rate (2.2%). Practical durations of SS and DS stretching did not influence leg or vertical stiffness during treadmill running. However, DS seems to result in a small increase in lower-limb force production which may influence running mechanics.

Superconducting cable cooling system by helium gas and a mixture of gas and liquid helium

DOEpatents

Dean, John W.

1977-01-01

Thermally contacting, oppositely streaming cryogenic fluid streams in the same enclosure in a closed cycle that changes from a cool high pressure helium gas to a cooler reduced pressure helium fluid comprised of a mixture of gas and boiling liquid so as to be near the same temperature but at different pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid in a go leg from a refrigerator at one end of the line as a high pressure helium gas near the normal boiling temperature of helium; then circulating the gas through an expander at the other end of the line where the gas becomes a mixture of reduced pressure gas and boiling liquid at its boiling temperature; then by circulating the mixture in a return leg that is separated from but in thermal contact with the gas in the go leg and in the same enclosure therewith; and finally returning the resulting low pressure gas to the refrigerator for compression into a high pressure gas at T.sub.2 is a closed cycle, where T.sub.1 >T.sub.2, the temperature distribution is such that the line temperature is nearly constant along its length from the refrigerator to the expander due to the boiling of the liquid in the mixture. A heat exchanger between the go and return lines removes the gas from the liquid in the return leg while cooling the go leg.

Changes in passive tension of muscle in humans and animals after eccentric exercise

PubMed Central

Whitehead, N P; Weerakkody, N S; Gregory, J E; Morgan, D L; Proske, U

2001-01-01

This is a report of experiments on ankle extensor muscles of human subjects and a parallel series on the medial gastrocnemius of the anaesthetised cat, investigating the origin of the rise in passive tension after a period of eccentric exercise. Subjects exercised their triceps surae of one leg eccentrically by walking backwards on an inclined, forward-moving treadmill. Concentric exercise required walking forwards on a backwards-moving treadmill. For all subjects the other leg acted as a control. Immediately after both eccentric and concentric exercise there was a significant drop in peak active torque, but only after eccentric exercise was this accompanied by a shift in optimum angle for torque generation and a rise in passive torque. In the eccentrically exercised group some swelling and soreness developed but not until 24 h post-exercise. In the animal experiments the contracting muscle was stretched by 6 mm at 50 mm s−1 over a length range symmetrical about the optimum length for tension generation. Measurements of passive tension were made before and after the eccentric contractions, using small stretches to a range of muscle lengths, or with large stretches covering the full physiological range. After 150 eccentric contractions, passive tension was significantly elevated over most of the range of lengths. Measurements of work absorption during stretch-release cycles showed significant increases after the contractions. It is suggested that the rise in passive tension in both human and animal muscles after eccentric contractions is the result of development of injury contractures in damaged muscle fibres. PMID:11389215

Anthropometry as a predictor of vertical jump heights derived from an instrumented platform.

PubMed

Caruso, John F; Daily, Jeremy S; Mason, Melissa L; Shepherd, Catherine M; McLagan, Jessica R; Marshall, Mallory R; Walker, Ron H; West, Jason O

2012-01-01

The current study purpose examined the vertical height-anthropometry relationship with jump data obtained from an instrumented platform. Our methods required college-aged (n = 177) subjects to make 3 visits to our laboratory to measure the following anthropometric variables: height, body mass, upper arm length (UAL), lower arm length, upper leg length, and lower leg length. Per jump, maximum height was measured in 3 ways: from the subjects' takeoff, hang times, and as they landed on the platform. Standard multivariate regression assessed how well anthropometry predicted the criterion variance per gender (men, women, pooled) and jump height method (takeoff, hang time, landing) combination. Z-scores indicated that small amounts of the total data were outliers. The results showed that the majority of outliers were from jump heights calculated as women landed on the platform. With the genders pooled, anthropometry predicted a significant (p < 0.05) amount of variance from jump heights calculated from both takeoff and hang time. The anthropometry-vertical jump relationship was not significant from heights calculated as subjects landed on the platform, likely due to the female outliers. Yet anthropometric data of men did predict a significant amount of variance from heights calculated when they landed on the platform; univariate correlations of men's data revealed that UAL was the best predictor. It was concluded that the large sample of men's data led to greater data heterogeneity and a higher univariate correlation. Because of our sample size and data heterogeneity, practical applications suggest that coaches may find our results best predict performance for a variety of college-aged athletes and vertical jump enthusiasts.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

PubMed

Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p < 0.05). Compared to DP approximately 14% higher speed was achieved when leg push-offs were added in G3 skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

Housing system, milk production, and zero-grazing effects on lameness and leg injury in dairy cows.

PubMed

Haskell, M J; Rennie, L J; Bowell, V A; Bell, M J; Lawrence, A B

2006-11-01

The aim of this study was to assess the effect of grazing (G) vs. zero-grazing (ZG), level of milk production, and quality and type of housing system [free stalls (FS) and straw yards (SY)] on the prevalence of lameness and leg injuries in dairy cows. Observations were made on 37 commercial dairy farms across Great Britain. A single visit of 5 d duration was made to each farm. During this visit, lameness scores and the incidence of swellings, rubs, and injuries to hocks and knees were recorded on all the peak- or mid-lactation cows. Aspects of the quality of housing and management that were likely to affect foot and leg health were recorded. There were more lame cows on ZG farms (39 +/- 0.02%) than on grazing (G) farms (15 +/- 0.01%), and lameness scores were higher on FS farms compared with SY farms (0.25 +/- 0.01 vs. 0.05 +/- 0.01). Cows on SY farms had fewer hock and knee injuries compared with FS farms. The frequency of knee swellings was higher on ZG farms (0.31 +/- 0.02) than on G farms (0.15 +/- 0.01). Aspects of the free-stall design affected foot and leg health. The number of hock swellings increased with increasing stall gradient (0.16 +/- 0.01 with no slope vs. 0.39 +/- 0.02 at a 0 to 1.5% slope). There was an interaction between the length of the free-stall lunging space and the hip width of the cow, indicating that the incidence of lameness is generally highest on farms with small free stalls and heavy cows. High levels of milk production did not affect lameness or leg injury. The results indicate that housing cows throughout the year potentially has a detrimental effect on foot and leg health. However, good free-stall design may reduce lameness and leg lesions.

Sleep management and the performance of eight sailors in the Tour de France à la voile yacht race.

PubMed

Léger, D; Elbaz, M; Raffray, T; Metlaine, A; Bayon, V; Duforez, F

2008-01-01

We observed how sailors manage their sleep and alertness before and during competition in a long-haul yacht race. Global performance of the teams was also recorded. We assessed eight sailors aged 21-30 years, split into four teams, who competed in the Tour de France à la Voile 2002 yacht race. Two phases of the race were examined: two legs in both the Atlantic Ocean and Mediterranean Sea. Sleep length, sleep debt, and sleepiness before competition and on board during the race were assessed using ambulatory polysomnography. Intermediate and final rankings were considered as a reflection of performance. A significant correlation was observed between the sleep debt before competition and the total sleep time on board during the Atlantic legs. The greater the sleep debt, the more sleepy the participants were. During the Mediterranean legs, almost all the sailors were deprived of sleep and slept during the daytime competitions. We observed that the final ranking in the race related to the sleep management strategy of the participants. In extreme competitive conditions, the effect of a good night's sleep before competition on performance is important. The strategy of the winners was to get sufficient sleep before each leg so as to be the most alert and efficient during the race.

Childhood stature and adult cancer risk: the Boyd Orr cohort.

PubMed

Whitley, Elise; Martin, Richard M; Smith, George Davey; Holly, Jeff M P; Gunnell, David

2009-03-01

Cancer risk in adulthood may be influenced by aspects of childhood diet. In the absence of direct dietary data, indirect measures of childhood diet and nutritional status, such as anthropometric measurements, may be useful in investigating diet-cancer associations. Previous studies suggest that taller adults may have increased cancer risk. Peak growth for different anthropometric measures occurs at different times and so differential associations with cancer risk may indicate periods of development that are particularly important in determining future risk. 2,642 traced members of the Boyd Orr cohort had measures of foot length, shoulder breadth, height, and leg length made when they were aged 2-14 years; trunk length was derived from the difference between overall height and leg length. Subjects were followed-up over 59 years to determine all-cause (n = 547) and site-specific (n = 97 for lung, 69 breast, 59 colorectal, 33 prostate, 320 not related to smoking) cancer deaths and registrations. There were no strong associations between childhood anthropometric measurements and adult cancer risk. Odds ratios (ORs) were broadly consistent with a slight increase in risk with increasing childhood stature but no single measure was of particular importance. The strongest associations were seen for breast cancer (OR per standard deviation increase in foot length: 1.16 (95% CI: 0.90, 1.51), shoulder breadth: 1.16 (0.91, 1.49) and trunk: 1.26 (1.00, 1.60), and prostate cancer (OR for foot length: 1.22 (0.86, 1.75)). There was little effect of adjustment for confounding factors and very limited evidence that associations differed with measures made prior to the onset of puberty (comparing the associations in children aged <8 vs. 8+ years). There was no evidence that any of the five indicators of childhood growth was more strongly related to cancer risk than the other measures.

[The concept and definition of locomotive syndrome in a super-aged society].

PubMed

Nakamura, Kozo; Yoshimura, Noriko; Akune, Toru; Ogata, Toru; Tanaka, Sakae

2014-10-01

The population of elderly individuals who need nursing care is rapidly increasing in Japan. Locomotive syndrome involves a decrease in mobility due to locomotive organ dysfunction, and increases risk for dependency on nursing care service. Because gait speed and chair stand time are correlated with such risks, patients with locomotive syndrome are assessed using brief methods such as the two-step test, which involves dividing the maximum stride length by the height of the patient, and the stand-up test, which involves standing on one or both legs at different heights. One leg standing and squatting are recommended as beneficial locomotive home exercises. Locomotive syndrome has been recognized widely in Japan, and included in the National Health Promotion Movement (2013-2022).

Multi-functional foot use during running in the zebra-tailed lizard (Callisaurus draconoides).

PubMed

Li, Chen; Hsieh, S Tonia; Goldman, Daniel I

2012-09-15

A diversity of animals that run on solid, level, flat, non-slip surfaces appear to bounce on their legs; elastic elements in the limbs can store and return energy during each step. The mechanics and energetics of running in natural terrain, particularly on surfaces that can yield and flow under stress, is less understood. The zebra-tailed lizard (Callisaurus draconoides), a small desert generalist with a large, elongate, tendinous hind foot, runs rapidly across a variety of natural substrates. We use high-speed video to obtain detailed three-dimensional running kinematics on solid and granular surfaces to reveal how leg, foot and substrate mechanics contribute to its high locomotor performance. Running at ~10 body lengths s(-1) (~1 m s(-1)), the center of mass oscillates like a spring-mass system on both substrates, with only 15% reduction in stride length on the granular surface. On the solid surface, a strut-spring model of the hind limb reveals that the hind foot saves ~40% of the mechanical work needed per step, significant for the lizard's small size. On the granular surface, a penetration force model and hypothesized subsurface foot rotation indicates that the hind foot paddles through fluidized granular medium, and that the energy lost per step during irreversible deformation of the substrate does not differ from the reduction in the mechanical energy of the center of mass. The upper hind leg muscles must perform three times as much mechanical work on the granular surface as on the solid surface to compensate for the greater energy lost within the foot and to the substrate.

Impairment in anthropometric parameters and body composition in females with classical 21-hydroxylase deficiency.

PubMed

Gonçalves, Ezequiel Moreira; de Lemos-Marini, Sofia Helena Valente; de Mello, Maricilda Palandi; Baptista, Maria Tereza Matias; D'Souza-Li, Lilia Freire Rodrigues; Baldin, Alexandre Duarte; Carvalho, Wellington Roberto Gomes; Farias, Edson Santos; Guerra-Junior, Gil

2009-06-01

The aim of this study was to evaluate the physical measurements and body composition of female patients with the classic form of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. Twenty-eight girls with CAH were classified according to both hormonal control (well or not well controlled) and the clinical form of the disease (simple virilizing or salt-wasting). In the control group, 112 healthy individuals were included, divided into two subgroups (male and female). Both patients and controls were subdivided by age into three groups according to pubertal stage: < or =10 years (prepubertal), 11-15 years (pubertal), and > or =15 years (postpubertal). Anthropometrical evaluations and bioelectrical impedance were used to obtain the physical measurement and body composition data. The patients with the simple virilizing form presented higher values for BMI, waist, arm fat area, and fat mass percentage. The not well controlled group presented shorter leg length. Values obtained for BMI as well as for arm fat area, brachial circumference, waist, hip, bi-iliac diameter and fat mass percentage were significantly higher in the patients than in the controls, whereas leg length, hand size and the percentages of water and lean mass were lower. Alterations in body composition were observed in all age groups, mainly by increase of fat mass with age. After puberty, impairments in limb measurements (leg, hand and foot) were more evident. Patients with CAH presented differences in anthropometric parameters but mainly in body composition. Hence, more comprehensive and careful anthropometric evaluation during monitoring of patients with CAH is recommended.

Changes in Running Mechanics During a 6-Hour Running Race.

PubMed

Giovanelli, Nicola; Taboga, Paolo; Lazzer, Stefano

2017-05-01

To investigate changes in running mechanics during a 6-h running race. Twelve ultraendurance runners (age 41.9 ± 5.8 y, body mass 68.3 ± 12.6 kg, height 1.72 ± 0.09 m) were asked to run as many 874-m flat loops as possible in 6 h. Running speed, contact time (t c ), and aerial time (t a ) were measured in the first lap and every 30 ± 2 min during the race. Peak vertical ground-reaction force (F max ), stride length (SL), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), vertical stiffness (k vert ), and leg stiffness (k leg ) were then estimated. Mean distance covered by the athletes during the race was 62.9 ± 7.9 km. Compared with the 1st lap, running speed decreased significantly from 4 h 30 min onward (mean -5.6% ± 0.3%, P < .05), while t c increased after 4 h 30 min of running, reaching the maximum difference after 5 h 30 min (+6.1%, P = .015). Conversely, k vert decreased after 4 h, reaching the lowest value after 5 h 30 min (-6.5%, P = .008); t a and F max decreased after 4 h 30 min through to the end of the race (mean -29.2% and -5.1%, respectively, P < .05). Finally, SL decreased significantly (-5.1%, P = .010) during the last hour of the race. Most changes occurred after 4 h continuous self-paced running, suggesting a possible time threshold that could affect performance regardless of absolute running speed.

Towards a general neural controller for quadrupedal locomotion.

PubMed

Maufroy, Christophe; Kimura, Hiroshi; Takase, Kunikatsu

2008-05-01

Our study aims at the design and implementation of a general controller for quadruped locomotion, allowing the robot to use the whole range of quadrupedal gaits (i.e. from low speed walking to fast running). A general legged locomotion controller must integrate both posture control and rhythmic motion control and have the ability to shift continuously from one control method to the other according to locomotion speed. We are developing such a general quadrupedal locomotion controller by using a neural model involving a CPG (Central Pattern Generator) utilizing ground reaction force sensory feedback. We used a biologically faithful musculoskeletal model with a spine and hind legs, and computationally simulated stable stepping motion at various speeds using the neuro-mechanical system combining the neural controller and the musculoskeletal model. We compared the changes of the most important locomotion characteristics (stepping period, duty ratio and support length) according to speed in our simulations with the data on real cat walking. We found similar tendencies for all of them. In particular, the swing period was approximately constant while the stance period decreased with speed, resulting in a decreasing stepping period and duty ratio. Moreover, the support length increased with speed due to the posterior extreme position that shifted progressively caudally, while the anterior extreme position was approximately constant. This indicates that we succeeded in reproducing to some extent the motion of a cat from the kinematical point of view, even though we used a 2D bipedal model. We expect that such computational models will become essential tools for legged locomotion neuroscience in the future.

Lower-limb growth: how predictable are predictions?

PubMed

Kelly, Paula M; Diméglio, Alain

2008-12-01

The purpose of this review is to clarify the different methods of predictions for growth of the lower limb and to propose a simplified method to calculate the final limb deficit and the correct timing of epiphysiodesis. Lower-limb growth is characterized by four different periods: antenatal growth (exponential); birth to 5 years (rapid growth); 5 years to puberty (stable growth); and puberty, which is the final growth spurt characterized by a rapid acceleration phase lasting 1 year followed by a more gradual deceleration phase lasting 1.5 years. The younger the child, the less precise is the prediction. Repeating measurements can increase the accuracy of predictions and those calculated at the beginning of puberty are the most accurate. The challenge is to reduce the margin of uncertainty. Confrontation of the different parameters-bone age, Tanner signs, annual growth velocity of the standing height, sub-ischial length and sitting height-is the most accurate method. Charts and diagrams are only models and templates. There are many mathematical equations in the literature; we must be able to step back from these rigid calculations because they are a false guarantee. The dynamic of growth needs a flexible approach. There are, however, some rules of thumb that may be helpful for different clinical scenarios. For congenital malformations, at birth the limb length discrepancy must be multiplied by 5 to give the final limb length discrepancy. Multiple by 3 at 1 year of age; by 2 at 3 years in girls and 4 years in boys; by 1.5 at 7 years in girls and boys, by 1.2 at 9 years in girls and 11 years in boys and by 1.1 at the onset of puberty (11 years bone age for girls and 13 years bone age for boys). For the timing of epiphysiodesis, several simple principles must be observed to reduce the margin of error; strict and repeated measurements, rigorous analysis of the data obtained, perfect evaluation of bone age with elbow plus hand radiographs and confirmation with Tanner signs. The decision should always be taken at the beginning of puberty. A simple rule is that, at the beginning of puberty, there is an average of 5 cm growth remaining at the knee. There are four common different scenarios: (1) A 5-cm discrepancy-epiphysiodesis of both femur and tibia at the beginning of puberty (11 years bone age girls and 13 years in boys). (2) A 4-cm discrepancy-epiphysiodesis of femur and tibia 6 months after the onset of puberty (11 years 6 months bone age girls, 13 years 6 months bone age boys, tri-radiate cartilage open). (3) A 3-cm discrepancy-epiphysiodesis of femur only at the start of puberty, (skeletal age of 11 years in girls and 13 years in boys). (4) A 2-cm discrepancy-epiphysiodesis of femur only, 1 year after the start of puberty (12 years bone age girls and 14 years in boys).

Biometric analysis of the clinical crown and the width/length ratio in the maxillary anterior region.

PubMed

Orozco-Varo, Ana; Arroyo-Cruz, Gema; Martínez-de-Fuentes, Rafael; Jiménez-Castellanos, Emilio

2015-06-01

Restorative dentistry often involves correcting tooth size discrepancies. Therefore, dental biometrics should play an important role in the planning of an esthetic restoration. The purpose of this study was to analyze the clinical crown width, length, and width/length ratio of maxillary central incisors, lateral incisors, and canines in an adult population. The study also aimed to determine whether a correlation exists between natural tooth dimensions and the optimal tooth dimension guidelines suggested for planning esthetic restorations. Stone casts were poured from irreversible hydrocolloid impressions of 412 healthy adult participants. These casts were used to measure the maximum mesiodistal width and maximum crown-root length of the maxillary central incisors, lateral incisors, and canines with a digital precision caliper (0.01 mm). The width/length ratio was calculated for each tooth, and 40 casts were selected to test the reliability of the measuring method. The mean age of the participants in the sample was 33.94 years; 60.7% were women and 39.3% were men. The mean width value was 8.71 mm for central incisors, 6.75 mm for lateral incisors, and 7.81 mm for canines. The mean length was 10.23 mm for central incisors, 8.59 mm for lateral incisors, and 9.93 mm for canines. The average width/length ratio was 85% for central incisors and 79% for lateral incisors and canines. The data obtained from the population studied are similar to those from previous research studies with similar methodology. However, great discrepancies in the absolute values were found when compared with other studies of ideal tooth dimension guidelines on the personal preferences and the esthetic perception of dentists. The perception of what is considered natural seems to differ from what is considered esthetically perfect. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study.

PubMed

Noormohammadpour, Pardis; Hosseini Khezri, Alireza; Linek, Paweł; Mansournia, Mohammad Ali; Hassannejad, Alireza; Younesian, Ali; Farahbakhsh, Farzin; Kordi, Ramin

2016-12-01

Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes. The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP. In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study). The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables. The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players.

Popcorn calcification in osteogenesis imperfecta: incidence, progression, and molecular correlation.

PubMed

Obafemi, Abimbola A; Bulas, Dorothy I; Troendle, James; Marini, Joan C

2008-11-01

Osteogenesis imperfecta (OI) is a heritable disorder characterized by osteoporosis and increased susceptibility to fracture. All children with severe OI have extreme short stature and some have "popcorn" calcifications, areas of disorganized hyperdense lines in the metaphysis and epiphysis around the growth plate on lower limb radiographs. Popcorn calcifications were noted on radiographs of two children with non-lethal type VIII OI, a recessive form caused by P3H1 deficiency. To determine the incidence, progression, and molecular correlations of popcorn calcifications, we retrospectively examined serial lower limb radiographs of 45 children with type III or IV OI and known dominant mutations in type I collagen. Popcorn calcifications were present in 13 of 25 type III (52%), but only 2 of 20 type IV (10%), OI children. The mean age of onset was 7.0 years, with a range of 4-14 years. All children with popcorn calcifications had this finding in their distal femora, and most also had calcifications in proximal tibiae. While unilateral popcorn calcification contributes to femoral growth deficiency and leg length discrepancy, severe linear growth deficiency, and metaphyseal flare do not differ significantly between type III OI patients with and without popcorn calcifications. The type I collagen mutations associated with popcorn calcifications occur equally in both COL1A1 and COL1A2, and have no preferential location along the chains. These data demonstrate that popcorn calcifications are a frequent feature of severe OI, but do not distinguish cases with defects in collagen structure (primarily dominant type III OI) or modification (recessive type VIII OI). Copyright 2008 Wiley-Liss, Inc.

Comparison of the Classifier Oriented Gait Score and the Gait Profile Score based on imitated gait impairments.

PubMed

Christian, Josef; Kröll, Josef; Schwameder, Hermann

2017-06-01

Common summary measures of gait quality such as the Gait Profile Score (GPS) are based on the principle of measuring a distance from the mean pattern of a healthy reference group in a gait pattern vector space. The recently introduced Classifier Oriented Gait Score (COGS) is a pathology specific score that measures this distance in a unique direction, which is indicated by a linear classifier. This approach has potentially improved the discriminatory power to detect subtle changes in gait patterns but does not incorporate a profile of interpretable sub-scores like the GPS. The main aims of this study were to extend the COGS by decomposing it into interpretable sub-scores as realized in the GPS and to compare the discriminative power of the GPS and COGS. Two types of gait impairments were imitated to enable a high level of control of the gait patterns. Imitated impairments were realized by restricting knee extension and inducing leg length discrepancy. The results showed increased discriminatory power of the COGS for differentiating diverse levels of impairment. Comparison of the GPS and COGS sub-scores and their ability to indicate changes in specific variables supports the validity of both scores. The COGS is an overall measure of gait quality with increased power to detect subtle changes in gait patterns and might be well suited for tracing the effect of a therapeutic treatment over time. The newly introduced sub-scores improved the interpretability of the COGS, which is helpful for practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

The Use of 3D Printing Technology in the Ilizarov Method Treatment: Pilot Study.

PubMed

Burzyńska, Karolina; Morasiewicz, Piotr; Filipiak, Jarosław

2016-01-01

Significant developments in additive manufacturing technology have occurred in recent years. 3D printing techniques can also be helpful in the Ilizarov method treatment. The aim of this study was to evaluate the usefulness of 3D printing technology in the Ilizarov method treatment. Physical models of bones used to plan the spatial design of Ilizarov external fixator were manufactured by FDM (Fused Deposition Modeling) spatial printing technology. Bone models were made of poly(L-lactide) (PLA). Printed 3D models of both lower leg bones allow doctors to prepare in advance for the Ilizarov method treatment: detailed consideration of the spatial configuration of the external fixation, experimental assembly of the Ilizarov external fixator onto the physical models of bones prior to surgery, planning individual osteotomy level and Kirschner wires introduction sites. Printed 3D bone models allow for accurate preparation of the Ilizarov apparatus spatially matched to the size of the bones and prospective bone distortion. Employment of the printed 3D models of bone will enable a more precise design of the apparatus, which is especially useful in multiplanar distortion and in the treatment of axis distortion and limb length discrepancy in young children. In the course of planning the use of physical models manufactured with additive technology, attention should be paid to certain technical aspects of model printing that have an impact on the accuracy of mapping of the geometry and physical properties of the model. 3D printing technique is very useful in 3D planning of the Ilizarov method treatment.

Biopsychosocial Profiles and Functional Correlates in Older Adults with Chronic Low Back Pain: A Preliminary Study.

PubMed

Weiner, Debra K; Gentili, Angela; Coffey-Vega, Katherine; Morone, Natalia; Rossi, Michelle; Perera, Subashan

2018-04-16

To describe key peripheral and central nervous system (CNS) conditions in a group of older adults with chronic low back pain (CLBP) and their association with pain severity and self-reported and performance-based physical function. Cross-sectional. Outpatient VA clinics. Forty-seven community-dwelling veterans with CLBP (age 68.0 ± 6.5 years, range = 60-88 years, 12.8% female, 66% white) participated. Data were collected on peripheral pain generators-body mass index, American College of Rheumatology hip osteoarthritis criteria, neurogenic claudication (i.e., spinal stenosis), sacroiliac joint (SIJ) pain, myofascial pain, leg length discrepancy (LLD), and iliotibial band pain; and CNS pain generators-anxiety (GAD-7), depression (PHQ-9), insomnia (Insomnia Severity Index), maladaptive coping (Fear Avoidance Beliefs Questionnaire, Cognitive Strategies Questionnaire), and fibromyalgia (fibromyalgia survey). Outcomes were pain severity (0 to 10 scale, seven-day average and worst), self-reported pain interference (Roland Morris [RM] questionnaire), and gait speed. Approximately 96% had at least one peripheral CLBP contributor, 83% had at least one CNS contributor, and 80.9% had both peripheral and CNS contributors. Of the peripheral conditions, only SIJ pain and LLD were associated with outcomes. All of the CNS conditions and SIJ pain were related to RM score. Only depression/anxiety and LLD were associated with gait speed. In this sample of older veterans, CLBP was a multifaceted condition. Both CNS and peripheral conditions were associated with self-reported and performance-based function. Additional investigation is required to determine the impact of treating these conditions on patient outcomes and health care utilization.

Correction of complex foot deformities using the Ilizarov external fixator.

PubMed

Kocaoğlu, Mehmet; Eralp, Levent; Atalar, Ata Can; Bilen, F Erkal

2002-01-01

There are many drawbacks to using conventional approaches to the treatment of complex foot deformities, like the increased risk of neurovascular injury, soft-tissue injury, and the shortening of the foot. An alternative approach that can eliminate these problems is the Ilizarov method. In the current study, a total of 23 deformed feet in 22 patients were treated using the Ilizarov method. The etiologic factors were burn contracture, poliomyelitis, neglected and relapsed clubfoot, trauma, gun shot injury, meningitis, and leg-length discrepancy (LLD). The average age of the patients was 18.2 (5-50) years. The mean duration of fixator application was 5.1 (2-14) months. We performed corrections without an osteotomy in nine feet and with an osteotomy in 14 feet. Additional bony corrective procedures included three tibial and one femoral osteotomies for lengthening and deformity correction, and one tibiotalar arthrodesis in five separate extremities. At the time of fixator removal, a plantigrade foot was achieved in 21 of the 23 feet by pressure mat analysis. Compared to preoperative status, gait was subjectively improved in all patients. Follow-up time from surgery averaged 25 months (13-38). Pin-tract problems were observed in all cases. Other complications were toe contractures in two feet, metatarsophalangeal subluxation from flexor tendon contractures in one foot, incomplete osteotomy in one foot, residual deformity in two feet, and recurrence of deformity in one foot. Our results indicate that the Ilizarov method is an effective alternative means of correcting complex foot deformities, especially in feet that previously have undergone surgery.

The radiological research for pelvis asymmetry of unilateral developmental dysplasia of the hip in adult

PubMed Central

Li, Ya-Min; Li, Jue-Hong; Li, Bin; Wang, Jia-Xing; Chen, Yun-Su

2016-01-01

Objectives To investigate whether adult patients with unilateral developmental dysplasia of the hip (UDDH) have pelvic asymmetry and what correlation existing between them. Methods A total of 100 adult patients with UDDH were enrolled in the retrospective observational study in Shanghai Jiaotong University Affiliated Sixth People’s Hospital, Shanghai, China, between January 2012 and February 2014. The anteroposterior pelvic radiographs were reviewed and the pelvic heights and ischium heights were measured and compared between the affected and non-affected sides to find out the relationship between the pelvic morphology and hip dysplasia. Results The pelvic heights demonstrated significant differences between the non-affected side and the affected side in patients with Crowe type II-IV UDDH (p<0.05), but not in patients with Crowe type I UDDH (p=0.09). There were significant differences in the bilateral ischium heights in patients with Crowe type III and IV UDDH (p<0.05), but not in patients with Crowe type I and II UDDH (p=0.78, p=0.055). In addition, the degree of hip dysplasia was positively associated with the degrees of asymmetry of pelvis (r=0.78, p<0.001) and ischium (r=0.72, p<0.001) in UDDH patients. Conclusion The pelvic asymmetry exists in adult patients with UDDH. In addition, the degree of asymmetry has correlation with the degree of hip dysplasia. We recommend that it should be taken more cautions to use teardrops and ischial tuberosity as anatomy landmarks to balance leg-length discrepancy for unilateral DDH patients in preoperative planning and total hip arthroplasty. PMID:27874150

Natural History of Aging in Cornelia de Lange Syndrome

PubMed Central

KLINE, ANTONIE D.; GRADOS, MARCO; SPONSELLER, PAUL; LEVY, HOWARD P.; BLAGOWIDOW, NATALIE; SCHOEDEL, CHRISTIANNE; RAMPOLLA, JONI; CLEMENS, DOUGLAS K.; KRANTZ, IAN; KIMBALL, AMY; PICHARD, CARMEN; TUCHMAN, DAVID

2016-01-01

Observations about the natural history of aging in Cornelia de Lange syndrome (CdLS) are made, based on 49 patients from a multidisciplinary clinic for adolescents and adults. The mean age was 17 years. Although most patients remain small, obesity may develop. Gastroesophageal reflux persists or worsens, and there are early long-term sequelae, including Barrett esophagus in 10%; other gastrointestinal findings include risk for volvulus, rumination, and chronic constipation. Submucous cleft palate was found in 14%, most undetected before our evaluation. Chronic sinusitis was noted in 39%, often with nasal polyps. Blepharitis improves with age; cataracts and detached retina may occur. Decreased bone density is observed, with occasional fractures. One quarter have leg length discrepancy and 39% scoliosis. Most females have delayed or irregular menses but normal gynecologic exams and pap smears. Benign prostatic hypertrophy occurred in one male prior to 40 years. The phenotype is variable, but there is a distinct pattern of facial changes with aging. Premature gray hair is frequent; two patients had cutis verticis gyrata. Behavioral issues and specific psychiatric diagnoses, including self-injury, anxiety, attention-deficit disorder, autistic features, depression, and obsessive-compulsive behavior, often worsen with age. This work presents some evidence for accelerated aging in CdLS. Of 53% with mutation analysis, 55% demonstrate a detectable mutation in NIPBL or SMC1A. Although no specific genotype–phenotype correlations have been firmly established, individuals with missense mutations in NIPBL and SMC1A appear milder than those with other mutations. Based on these observations, recommendations for clinical management of adults with CdLS are made. PMID:17640042

[Stump forming after traumatic foot amputation of a child--description of a new surgical procedure and literature review of lawnmower accidents].

PubMed

Bayer, J; Zajonc, H; Strohm, P C; Vohrer, M; Maier-Lenz, D; Südkamp, N P; Schwering, L

2009-01-01

Amputation injuries in children occur in motor vehicle, farming and, importantly, lawn mower accidents. Treatment of lawn mower related injuries is complicated by gross wound contamination, avascular tissue, soft tissue defects and exposed bone. Many treatment options exist and often an adequate prosthetic supply is needed for rehabilitation. We report on an 8-year old boy who got under a ride-on lawn mower and sustained a subtotal amputation of his right foot. After initial surgery an amputation was subsequently necessary. For this, it had to be taken into account that the traumatic loss of the talus, calcaneus and parts of the cuboid bone would result in a length shortening of the right leg and so far not injured metatarsal and tarsal bones had to be sacrificed. Thus, we aimed to develop a new operation technique to optimize stump length as well as preserve tarsal bones and the possibility of limb growth. In order to achieve this, we performed a new stump forming operation in which we integrated uninjured tarsal and metatarsal bones. First a Lisfranc's amputation was performed and a metatarsal bone was kept aside. The talus, calcaneus as well as the cuboid bone were either completely or almost completely destroyed and were removed. The remaining cuneiform bones were transfixed by a notched metatarsal bone, thus achieving a tarsal arthrodesis, and the cartilages of the proximal joint surfaces were removed. The cartilage of the cranial and caudal navicular as well as the distal tibial joint surface was also removed and an arthrodesis between the distal tibia and the navicular bone was achieved by crossed Kirschner wires. Finally the cuneiform bones were placed inferior to the navicular bone. Further stump coverage was managed by skin and muscle flaps as well as split skin graft. Our patient was discharged on day 34. A fluent gait without crutches as well as sports activities were possible again as early as 6 1/2 months after the injury. Using our stump forming technique we hope to prevent some complications of amputation injuries. Because of the intact epiphysis a bone overgrowth is hopefully prevented and growth potential is preserved and by inclusion of tarsal and metatarsal bones in the stump formation a length discrepancy is minimized. (c) Georg Thieme Verlag KG Stuttgart-New York.

Telling tails: selective pressures acting on investment in lizard tails.

PubMed

Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

2013-01-01

Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P < 0.001; also significant for five of the six families tested separately), as do longer (all species, P < 0.001; Iguanidae, P < 0.05; Lacertidae, P < 0.001; Scindidae, P < 0.001), climbing (all species, P < 0.05), and diurnal (all species, P < 0.01; Pygopodidae, P < 0.01) species; geckos without specialized tails (P < 0.05); or active-foraging skinks (P < 0.05). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., P < 0.01; Scindidae, P < 0.05), larger skinks (P < 0.05), climbing geckos (P < 0.05), or active-foraging iguanids (P < 0.05). The selective advantage of investing in a relatively longer tail may be due to locomotor mechanics, although the patterns observed are also largely consistent with predictions based on predation pressure.

A principal components approach to parent-to-newborn body composition associations in South India

PubMed Central

Veena, Sargoor R; Krishnaveni, Ghattu V; Wills, Andrew K; Hill, Jacqueline C; Fall, Caroline HD

2009-01-01

Background Size at birth is influenced by environmental factors, like maternal nutrition and parity, and by genes. Birth weight is a composite measure, encompassing bone, fat and lean mass. These may have different determinants. The main purpose of this paper was to use anthropometry and principal components analysis (PCA) to describe maternal and newborn body composition, and associations between them, in an Indian population. We also compared maternal and paternal measurements (body mass index (BMI) and height) as predictors of newborn body composition. Methods Weight, height, head and mid-arm circumferences, skinfold thicknesses and external pelvic diameters were measured at 30 ± 2 weeks gestation in 571 pregnant women attending the antenatal clinic of the Holdsworth Memorial Hospital, Mysore, India. Paternal height and weight were also measured. At birth, detailed neonatal anthropometry was performed. Unrotated and varimax rotated PCA was applied to the maternal and neonatal measurements. Results Rotated PCA reduced maternal measurements to 4 independent components (fat, pelvis, height and muscle) and neonatal measurements to 3 components (trunk+head, fat, and leg length). An SD increase in maternal fat was associated with a 0.16 SD increase (β) in neonatal fat (p < 0.001, adjusted for gestation, maternal parity, newborn sex and socio-economic status). Maternal pelvis, height and (for male babies) muscle predicted neonatal trunk+head (β = 0. 09 SD; p = 0.017, β = 0.12 SD; p = 0.006 and β = 0.27 SD; p < 0.001). In the mother-baby and father-baby comparison, maternal BMI predicted neonatal fat (β = 0.20 SD; p < 0.001) and neonatal trunk+head (β = 0.15 SD; p = 0.001). Both maternal (β = 0.12 SD; p = 0.002) and paternal height (β = 0.09 SD; p = 0.030) predicted neonatal trunk+head but the associations became weak and statistically non-significant in multivariate analysis. Only paternal height predicted neonatal leg length (β = 0.15 SD; p = 0.003). Conclusion Principal components analysis is a useful method to describe neonatal body composition and its determinants. Newborn adiposity is related to maternal nutritional status and parity, while newborn length is genetically determined. Further research is needed to understand mechanisms linking maternal pelvic size to fetal growth and the determinants and implications of the components (trunk v leg length) of fetal skeletal growth. PMID:19236724

Leg tendon glands in male bumblebees ( Bombus terrestris): structure, secretion chemistry, and possible functions

NASA Astrophysics Data System (ADS)

Jarau, Stefan; Žáček, Petr; Šobotník, Jan; Vrkoslav, Vladimír; Hadravová, Romana; Coppée, Audrey; Vašíčková, Soňa; Jiroš, Pavel; Valterová, Irena

2012-12-01

Among the large number of exocrine glands described in bees, the tarsal glands were thought to be the source of footprint scent marks. However, recent studies showed that the compounds used for marking by stingless bees are secreted by leg tendon instead of tarsal glands. Here, we report on the structure of leg tendon glands in males of Bombus terrestris, together with a description of the chemical composition of their secretions and respective changes of both during the males' lives. The ultrastructure of leg tendon glands shows that the secretory cells are located in three independent regions, separated from each other by unmodified epidermal cells: in the femur, tibia, and basitarsus. Due to the common site of secretion release, the organ is considered a single secretory gland. The secretion of the leg tendon glands of B. terrestris males differs in its composition from those of workers and queens, in particular by (1) having larger proportions of compounds with longer chain lengths, which we identified as wax esters; and (2) by the lack of certain hydrocarbons (especially long chain dienes). Other differences consist in the distribution of double bond positions in the unsaturated hydrocarbons that are predominantly located at position 9 in males but distributed at seven to nine different positions in the female castes. Double bond positions may change chemical and physical properties of a molecule, which can be recognized by the insects and, thus, may serve to convey specific information. The function of male-specific compounds identified from their tendon glands remains elusive, but several possibilities are discussed.

Compression member response of double steel angles on truss structure with member length variation

NASA Astrophysics Data System (ADS)

Hasibuan, Purwandy; Panjaitan, Arief; Haiqal, Muhammad

2018-05-01

One type of structures that implements steel angles as its members is truss system of telecommunication tower. For this structure, reinforcements on tower legs are also needed when antennas and microwaves installation placed on the peak of tower increases in quantity. One type of reinforcement methods commonly used is by increasing areas section capacity, where tower leg consisted of single angle section will be reinforced to be double angle sections. Regarding this case, this research discussed behavior two types of double angle steel section 2L 30.30.3 that were designed identically in area section but vary in length: 103 cm and 83 cm. At the first step, compression member together with tension member was formed to be a truss system, where compression and tension member were met at the joint plate. Schematic loading was implemented by giving tension loading on the joint plate, and this loading was terminated when each specimen reached its failure. Research findings showed that implementing shorter double angle (83 cm) sections, increased compression strength of steel angle section up to 13 %. Significant deformation occurring only on the flange for both of specimens indicated that implementing double angle is effective to prevent lateral-torsional buckling.

THE EFFECT OF THE GROWTH HORMONE FROM THE ANTERIOR LOBE OF THE PITUITARY ON BONE UNDER CONDITIONS OF IRRADIATION (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanova, E.A.

1963-05-21

Young rats 3 to 4 days old were given an x-ray dose of 1000 r on the left hind leg. A daily dose of 200 gamma of growth hormone obtained from the pituitary of a bull was administered, until the animals were killed on the 36th, 41st, and 44th days after the irradiation. The length of the tibia in the left and right legs was determined by x rays. In the irradiated animals, the ratio of the length of the left tibia to the right tibia was about 0.50, and the introduction of growth hormone into the rat had onlymore » a slight effect on tibial growth. The bones were then fixed in a Zenkerformalin fluid, and cytological studies were carried out. These studies show that irradiation of the extremity of a four-day rat with an x-ray dose of 2000 r resulted in deep disturbances in the cartilage bone with subsequent arrest in the development of the bone. The introduction of growth hormone ameliorated the changes in bone structure, but did not result in normal bone development. (TTT)« less

Effect of reduced gravity on the preferred walk-run transition speed

NASA Technical Reports Server (NTRS)

Kram, R.; Domingo, A.; Ferris, D. P.

1997-01-01

We investigated the effect of reduced gravity on the human walk-run gait transition speed and interpreted the results using an inverted-pendulum mechanical model. We simulated reduced gravity using an apparatus that applied a nearly constant upward force at the center of mass, and the subjects walked and ran on a motorized treadmill. In the inverted pendulum model for walking, gravity provides the centripetal force needed to keep the pendulum in contact with the ground. The ratio of the centripetal and gravitational forces (mv2/L)/(mg) reduces to the dimensionless Froude number (v2/gL). Applying this model to a walking human, m is body mass, v is forward velocity, L is leg length and g is gravity. In normal gravity, humans and other bipeds with different leg lengths all choose to switch from a walk to a run at different absolute speeds but at approximately the same Froude number (0.5). We found that, at lower levels of gravity, the walk-run transition occurred at progressively slower absolute speeds but at approximately the same Froude number. This supports the hypothesis that the walk-run transition is triggered by the dynamics of an inverted-pendulum system.

Patient-specific instrumentation in total knee arthroplasty: simpler, faster and more accurate than standard instrumentation-a randomized controlled trial.

PubMed

Vide, João; Freitas, Tânia Pinto; Ramos, Acácio; Cruz, Henrique; Sousa, João Paulo

2017-08-01

This randomized controlled trial was conducted to compare patient-specific instrumentation (PSI) to standard instrumentation regarding efficacy to achieve a good coronal alignment and differences in surgical time, blood loss and length of stay. Ninety-five of 100 randomized patients eligible for total knee arthroplasty were analysed. PSI with magnetic resonance and long-leg radiograph was performed in 47 patients, while 48 patients received standard instrumentation. Primary outcome measure was coronal alignment, evaluated with long-leg radiograph. Deviation >3° varus/valgus was considered an outlier. Surgical time was compared from skin to skin. Length of stay was a post hoc analysis. Blood loss was evaluated comparing the number of blood units spent, fall in haemoglobin and haematocrit levels. Standard instrumentation had a higher number of outliers in the coronal alignment with a relative risk of 3.015, compared to PSI. Surgical time was reduced by 18 min (24.8 %) with the PSI, as well as length of stay, with a half-day reduction. Number of blood units spent was significantly less in the PSI group. Relative risk of transfusion was 7.09 for patients in the standard instrumentation group. Difference in Hg and Htc levels were not significant. No patient had to abandon PSI. Minor changes to preoperative plan occurred in 14.9 % of the patient: cut review in 4.3 % and insert change in 10.6 %. Patient-specific instrumentation (PSI) is able to provide important advantages over standard instrumentation in total knee arthroplasty: it lowers the risk of outliers and transfusion, is a faster procedure and enables a shorter length of stay with a low rate of intraoperative adjustments. I.

Padded self-adhesive strap immobilization following newborn bladder exstrophy closure: the Utah straps.

PubMed

Wallis, M Chad; Oottamasathien, Siam; Wicher, Chris; Hadley, David; Snow, Brent W; Cartwright, Patrick C

2013-12-01

Several methods have been described for immobilization of the pelvis following bladder exstrophy closure, which can be challenging to manage. We hypothesized that immobilization can be significantly simplified using a modified mermaid wrap with padded Velcro® straps around the thigh and lower leg. We retrospectively reviewed all patients who underwent bladder exstrophy closure in the newborn period at our institution from 1990 through 2010. Patients with cloacal exstrophy and those who underwent delayed closure due to other medical conditions were excluded. We collected data on closure technique, length of stay and complications of the primary closure as outcomes. A total of 20 boys and 7 girls underwent closure of classic bladder exstrophy. Followup ranged from 2 to 22 years. Seven boys underwent complete primary repair and 13 underwent staged repair. All patients had the legs stabilized with a modified wrap technique using 2 lengths of Velcro straps lined with self-adhering open cell foam pads for 3 weeks. Complications of exstrophy closure included bladder dehiscence in 1 patient (4%) and incisional hernia in 2 (7%). Following complete primary repair urethrocutaneous fistula developed in 2 patients and urethral stricture in 2. Average length of stay for patients without significant prematurity was 15 days. Padded Velcro strap immobilization simplifies postoperative care, provides secure fixation, decreases length of stay, and enables parents to hold and bond with the child shortly after repair. We advocate this simplified technique, which can be applied with a rate of complications that is comparable to other procedures. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

[Limb lengthening in dwarfism].

PubMed

Correll, J; Held, P

2000-09-01

Limb lengthening in dwarfism has become a standardised procedure with a good prognosis. In most cases external fixation is used. Gain of leg length up to 15 cm and more is possible in the lower leg and the femur and 8.5 cm in the humerus. Limb lengthening is useful in many cases of dwarfism due to skeletal dysplasia. There are a number of risks and possible complications involved and the procedure also requires considerable time. We report the results of 48 patients with dwarfism operated on in the Orthopädische Kinderklinik Aschau (Orthopaedic Hospital for Children). It must not be recommended as a normal tool in handling the problems of dwarfism, but it makes sense in some cases of dwarfism. We describe and discuss the prerequisites for the operative treatment.

Polarizing PVC--A Discrepant Event

ERIC Educational Resources Information Center

Headly, David; Karabatek, Mohamed

2016-01-01

This article describes an experiment teaching polarization phenomena and the Triboelectric Series in a unit on electrostatics. Using rods (2-3 ft in length) made from wood, aluminum, PVC, and Plexiglas on an inverted watch glass, these items demonstrated to the class how a party balloon rubbed with fake rabbit fur (charging the balloon negative)…

Comparison of Dynamic Balance in Collegiate Field Hockey and Football Players Using Star Excursion Balance Test

PubMed Central

Bhat, Rashi; Moiz, Jamal Ali

2013-01-01

Purpose The preliminary study aimed to compare dynamic balance between collegiate athletes competing or training in football and hockey using star excursion balance test. Methods A total thirty university level players, football (n = 15) and field hockey (n = 15) were participated in the study. Dynamic balance was assessed by using star excursion balance test. The testing grid consists of 8 lines each 120 cm in length extending from a common point at 45° increments. The subjects were instructed to maintain a stable single leg stance with the test leg with shoes off and to reach for maximal distance with the other leg in each of the 8 directions. A pencil was used to point and read the distance to which each subject's foot reached. The normalized leg reach distances in each direction were summed for both limbs and the total sum of the mean of summed normalized distances of both limbs were calculated. Results There was no significant difference in all the directions of star excursion balance test scores in both the groups. Additionally, composite reach distances of both groups also found non-significant (P=0.5). However, the posterior (P=0.05) and lateral (P=0.03) normalized reach distances were significantly more in field hockey players. Conclusion Field hockey players and football players did not differ in terms of dynamic balance. PMID:24427482

Comparison of dynamic balance in collegiate field hockey and football players using star excursion balance test.

PubMed

Bhat, Rashi; Moiz, Jamal Ali

2013-09-01

The preliminary study aimed to compare dynamic balance between collegiate athletes competing or training in football and hockey using star excursion balance test. A total thirty university level players, football (n = 15) and field hockey (n = 15) were participated in the study. Dynamic balance was assessed by using star excursion balance test. The testing grid consists of 8 lines each 120 cm in length extending from a common point at 45° increments. The subjects were instructed to maintain a stable single leg stance with the test leg with shoes off and to reach for maximal distance with the other leg in each of the 8 directions. A pencil was used to point and read the distance to which each subject's foot reached. The normalized leg reach distances in each direction were summed for both limbs and the total sum of the mean of summed normalized distances of both limbs were calculated. There was no significant difference in all the directions of star excursion balance test scores in both the groups. Additionally, composite reach distances of both groups also found non-significant (P=0.5). However, the posterior (P=0.05) and lateral (P=0.03) normalized reach distances were significantly more in field hockey players. Field hockey players and football players did not differ in terms of dynamic balance.

Interconnect patterns for printed organic thermoelectric devices with large fill factors

NASA Astrophysics Data System (ADS)

Gordiz, Kiarash; Menon, Akanksha K.; Yee, Shannon K.

2017-09-01

Organic materials can be printed into thermoelectric (TE) devices for low temperature energy harvesting applications. The output voltage of printed devices is often limited by (i) small temperature differences across the active materials attributed to small leg lengths and (ii) the lower Seebeck coefficient of organic materials compared to their inorganic counterparts. To increase the voltage, a large number of p- and n-type leg pairs is required for organic TEs; this, however, results in an increased interconnect resistance, which then limits the device output power. In this work, we discuss practical concepts to address this problem by positioning TE legs in a hexagonal closed-packed layout. This helps achieve higher fill factors (˜91%) than conventional inorganic devices (˜25%), which ultimately results in higher voltages and power densities due to lower interconnect resistances. In addition, wiring the legs following a Hilbert spacing-filling pattern allows for facile load matching to each application. This is made possible by leveraging the fractal nature of the Hilbert interconnect pattern, which results in identical sub-modules. Using the Hilbert design, sub-modules can better accommodate non-uniform temperature distributions because they naturally self-localize. These device design concepts open new avenues for roll-to-roll printing and custom TE module shapes, thereby enabling organic TE modules for self-powered sensors and wearable electronic applications.

Comparative functional analyses of ultrabithorax reveal multiple steps and paths to diversification of legs in the adaptive radiation of semi-aquatic insects.

PubMed

Khila, Abderrahman; Abouheif, Ehab; Rowe, Locke

2014-08-01

Invasion of new ecological habitats is often associated with lineage diversification, yet the genetic changes underlying invasions and radiations are poorly understood. Over 200 million years ago, the semi-aquatic insects invaded water surface from a common terrestrial ancestor and diversified to exploit a wide array of niches. Here, we uncover the changes in regulation and function of the gene Ultrabithorax associated with both the invasion of water surface and the subsequent diversification of the group. In the common ancestor of the semi-aquatic insects, a novel deployment of Ubx protein in the mid-legs increased their length, thereby enhancing their role in water surface walking. In derived lineages that specialize in rowing on the open water, additional changes in the timing of Ubx expression further elongated the mid-legs thereby facilitating their function as oars. In addition, Ubx protein function was selectively reversed to shorten specific rear-leg segments, thereby enabling their function as rudders. These changes in Ubx have generated distinct niche-specialized morphologies that account for the remarkable diversification of the semi-aquatic insects. Therefore, changes in the regulation and function of a key developmental gene may facilitate both the morphological change necessary to transition to novel habitats and fuel subsequent morphological diversification. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

The effect of rider weight and additional weight in Icelandic horses in tölt: part II. Stride parameters responses.

PubMed

Gunnarsson, V; Stefánsdóttir, G J; Jansson, A; Roepstorff, L

2017-09-01

This study investigated the effects of rider weight in the BW ratio (BWR) range common for Icelandic horses (20% to 35%), on stride parameters in tölt in Icelandic horses. The kinematics of eight experienced Icelandic school horses were measured during an incremental exercise test using a high-speed camera (300 frames/s). Each horse performed five phases (642 m each) in tölt at a BWR between rider (including saddle) and horse starting at 20% (BWR20) and increasing to 25% (BWR25), 30% (BWR30), 35% (BWR35) and finally 20% (BWR20b) was repeated. One professional rider rode all horses and weight (lead) was added to saddle and rider as needed. For each phase, eight strides at speed of 5.5 m/s were analyzed for stride duration, stride frequency, stride length, duty factor (DF), lateral advanced placement, lateral advanced liftoff, unipedal support (UPS), bipedal support (BPS) and height of front leg action. Stride length became shorter (Y=2.73-0.004x; P0.05). In conclusion, increased BWR decreased stride length and increased DF proportionally to the same extent in all limbs, whereas BPS increased at the expense of decreased UPS. These changes can be expected to decrease tölt quality when subjectively evaluated according to the breeding goals for the Icelandic horse. However, beat, symmetry and height of front leg lifting were not affected by BWR.

Exceptional running and turning performance in a mite.

PubMed

Rubin, Samuel; Young, Maria Ho-Yan; Wright, Jonathan C; Whitaker, Dwight L; Ahn, Anna N

2016-03-01

The Southern California endemic mite Paratarsotomus macropalpis was filmed in the field on a concrete substrate and in the lab to analyze stride frequency, gait and running speed under different temperature conditions and during turning. At ground temperatures ranging from 45 to 60 °C, mites ran at a mean relative speed of 192.4 ± 2.1 body lengths (BL) s(-1), exceeding the highest previously documented value for a land animal by 12.5%. Stride frequencies were also exceptionally high (up to 135 Hz), and increased with substrate temperature. Juveniles exhibited higher relative speeds than adults and possess proportionally longer legs, which allow for greater relative stride lengths. Although mites accelerated and decelerated rapidly during straight running (7.2 ± 1.2 and -10.1 ± 2.1 m s(-2), respectively), the forces involved were comparable to those found in other animals. Paratarsotomus macropalpis employs an alternating tetrapod gait during steady running. Shallow turns were accomplished by a simple asymmetry in stride length. During tight turns, mites pivoted around the tarsus of the inside third leg (L3), which thus behaved like a grappling hook. Pivot turns were characterized by a 42% decrease in turning radius and a 40% increase in angular velocity compared with non-pivot turns. The joint angle amplitudes of the inner L2 and L3 were negligible during a pivot turn. While exceptional, running speeds in P. macropalpis approximate values predicted from inter-specific scaling relationships. © 2016. Published by The Company of Biologists Ltd.

Allometric variation among juvenile, adult male and female eastern bearded dragons Pogona barbata (Cuvier, 1829), with comments on the behavioural implications.

PubMed

Wotherspoon, Danny; Burgin, Shelley

2011-02-01

The functional significance of allometric change in reptiles has received limited attention and the reason for such changes has been regarded as 'obscure'. In this paper we report data on the Australian Pogona barbata, the eastern bearded dragon, from across their range and review changes in allometric growth among juveniles, and adult males and females and consider the functional relevance of these changes. There were significant differences in the population for mass, tail length, tail width, rear leg length and jaw length. These differences were consistent with differences required in locomotor performance and thus habitat use, together with access to different preferred dietary components. Crown Copyright © 2011. Published by Elsevier GmbH. All rights reserved.

The effects of massage therapy after decompression and fusion surgery of the lumbar spine: a case study.

PubMed

Keller, Glenda

2012-01-01

Spinal fusion and decompression surgery of the lumbar spine are common procedures for problems such as disc herniations. Various studies for postoperative interventions have been conducted; however, no massage therapy studies have been completed. The objective of this study is to determine if massage therapy can beneficially treat pain and dysfunction associated with lumbar spinal decompression and fusion surgery. Client is a 47-year-old female who underwent spinal decompression and fusion surgery of L4/L5 due to chronic disc herniation symptoms. The research design was a case study in a private clinic involving the applications of seven, 30-minute treatments conducted over eight weeks. Common Swedish massage and myofascial techniques were applied to the back, shoulders, posterior hips, and posterior legs. Outcomes were assessed using the following measures: VAS pain scale, Hamstring Length Test, Oswestry Disability Index, and the Roland-Morris Disability Questionnaire. Hamstring length improved (in degrees of extension) from pretreatment measurements in the right leg of 40° and left leg 65° to post-treatment measurement at the final visit, when the results were right 50° and left 70°. The Oswestry Disability Index improved 14%, from 50% to 36% disability. Roland-Morris Disability decreased 1 point, from 3/24 to 2/24. The VAS pain score decreased by 2 points after most treatments, and for three of the seven treatments, client had a post-treatment score of 0/10. Massage for pain had short-term effects. Massage therapy seemed to lengthen the hamstrings bilaterally. Massage therapy does appear to have positive effects in the reduction of disability. This study is beneficial for understanding the relationship between massage therapy and clients who have undergone spinal decompression and fusion. Further research is warranted.

Immediate effects of a single session of robot-assisted gait training using Hybrid Assistive Limb (HAL) for cerebral palsy

PubMed Central

Matsuda, Mayumi; Mataki, Yuki; Mutsuzaki, Hirotaka; Yoshikawa, Kenichi; Takahashi, Kazushi; Enomoto, Keiko; Sano, Kumiko; Mizukami, Masafumi; Tomita, Kazuhide; Ohguro, Haruka; Iwasaki, Nobuaki

2018-01-01

[Purpose] Robot-assisted gait training (RAGT) using Hybrid Assistive Limb (HAL, CYBERDYNE) was previously reported beneficial for stroke and spinal cord injury patients. Here, we investigate the immediate effect of a single session of RAGT using HAL on gait function for cerebral palsy (CP) patients. [Subjects and Methods] Twelve patients (average age: 16.2 ± 7.3 years) with CP received a single session of RAGT using HAL. Gait speed, step length, cadence, single-leg support per gait cycle, hip and knee joint angle in stance, and swing phase per gait cycle were assessed before, during, and immediately after HAL intervention. [Results] Compared to baseline values, single-leg support per gait cycle (64.5 ± 15.8% to 69.3 ± 12.1%), hip extension angle in mid-stance (149.2 ± 19.0° to 155.5 ± 20.1°), and knee extension angle in mid-stance (137.6 ± 20.2° to 143.1 ± 19.5°) were significantly increased immediately after intervention. Further, the knee flexion angle in mid-swing was significantly decreased immediately after treatment (112.0 ± 15.5° to 105.2 ± 17.1°). Hip flexion angle in mid-swing also decreased following intervention (137.2 ± 14.6° to 129.7 ± 16.6°), but not significantly. Conversely, gait speed, step length, and cadence were unchanged after intervention. [Conclusion] A single-time RAGT with HAL improved single-leg support per gait cycle and hip and knee joint angle during gait, therapeutically improving gait function in CP patients. PMID:29545679

Mechanical alterations during interval-training treadmill runs in high-level male team-sport players.

PubMed

Girard, Olivier; Brocherie, Franck; Morin, Jean-Benoit; Millet, Grégoire P

2017-01-01

To examine mechanical alterations during interval-training treadmill runs in high-level team-sport players. Within-participants repeated measures. Twenty high-level male field-hockey players performed six 30-s runs at 5.53±0.19ms -1 corresponding to 115% of their velocity associated with maximal oxygen uptake (vVO 2max ) with 30-s passive recovery on an instrumented treadmill. Continuous measurement of running kinetics/kinematics and spring-mass characteristics were performed and values were subsequently averaged over 20s (8th-28ths) for comparison. Contact time (+1.1±4.3%; p=0.044), aerial time (+4.1±5.3%; p=0.001), step length (+2.4±2.2%; p<0.001) along with mean loading rates (+7.1±10.6%; p=0.026) increased from the first to the last interval, whereas step frequency (-2.3±2.1%; p<0.001) decreased. Both centre of mass vertical displacement (+3.0±6.0%; p<0.001) and leg compression (+2.8±9.7%; p=0.036), but not peak vertical forces (0.0±4.1%; p=0.761), increased with fatigue. Vertical stiffness decreased (-2.8±6.9%; p=0.012), whereas leg stiffness did not change across intervals (p=0.149). During interval-training treadmill runs, high-level team-sport players modified their mechanical behaviour towards lower vertical stiffness while preserving a constant leg stiffness. Maintenance of running velocity induced longer step lengths and decreased step frequencies that were also accompanied by increased impact loading rates. These mechanical alterations occurred early during the set. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Immediate effects of a single session of robot-assisted gait training using Hybrid Assistive Limb (HAL) for cerebral palsy.

PubMed

Matsuda, Mayumi; Mataki, Yuki; Mutsuzaki, Hirotaka; Yoshikawa, Kenichi; Takahashi, Kazushi; Enomoto, Keiko; Sano, Kumiko; Mizukami, Masafumi; Tomita, Kazuhide; Ohguro, Haruka; Iwasaki, Nobuaki

2018-02-01

[Purpose] Robot-assisted gait training (RAGT) using Hybrid Assistive Limb (HAL, CYBERDYNE) was previously reported beneficial for stroke and spinal cord injury patients. Here, we investigate the immediate effect of a single session of RAGT using HAL on gait function for cerebral palsy (CP) patients. [Subjects and Methods] Twelve patients (average age: 16.2 ± 7.3 years) with CP received a single session of RAGT using HAL. Gait speed, step length, cadence, single-leg support per gait cycle, hip and knee joint angle in stance, and swing phase per gait cycle were assessed before, during, and immediately after HAL intervention. [Results] Compared to baseline values, single-leg support per gait cycle (64.5 ± 15.8% to 69.3 ± 12.1%), hip extension angle in mid-stance (149.2 ± 19.0° to 155.5 ± 20.1°), and knee extension angle in mid-stance (137.6 ± 20.2° to 143.1 ± 19.5°) were significantly increased immediately after intervention. Further, the knee flexion angle in mid-swing was significantly decreased immediately after treatment (112.0 ± 15.5° to 105.2 ± 17.1°). Hip flexion angle in mid-swing also decreased following intervention (137.2 ± 14.6° to 129.7 ± 16.6°), but not significantly. Conversely, gait speed, step length, and cadence were unchanged after intervention. [Conclusion] A single-time RAGT with HAL improved single-leg support per gait cycle and hip and knee joint angle during gait, therapeutically improving gait function in CP patients.

Correlation of the tibial tuberosity-trochlear groove distance with the Q-angle.

PubMed

Dickschas, Jörg; Harrer, Jörg; Bayer, Thomas; Schwitulla, Judith; Strecker, Wolf

2016-03-01

The Q-angle has been used for years to quantify lateralization of the patella. The tibial tuberosity-trochlea groove distance (TT-TG distance) was introduced to analyse patellar tracking. Does a significant correlation exist between these two parameters? Do other significant interrelations exist between the Q-angle/TT-TG distance, torsion of the femur and tibia, the frontal axis, overall leg length, gender, former patellar dislocation, BMI? One hundred knees in 55 patients with patellofemoral symptoms were included in a prospective study. All patients underwent clinical examination, including measurement of the Q-angle. A torsional CT was obtained from all patients. The correlation coefficient was 0.33/0.34 (left/right leg), showing that the TT-TG distance tends to rise in direct ratio to a rising Q-angle. Thus, a significant correlation was found (p = 0.017). Femoral and tibial torsion had a positive effect on the TT-TG distance, but showed no significant correlation. Leg length had a significant effect on the TT-TG distance (p = 0.04). The frontal axis had a nonsignificant influence on the Q-angle or TT-TG distance. On average, the Q-angle in women was 2.38° greater than it was in men, but the difference was not significant. A significant correlation was noted between the Q-angle and the TT-TG distance. Both depend on various parameters and must be assessed for the analysis of patellofemoral maltracking. The Q-angle did not differ significantly between men and women; thus, the conclusion is that no different ranges need not be used. Diagnostic study, Level III.

Terahertz atmospheric attenuation and continuum effects

NASA Astrophysics Data System (ADS)

Slocum, David M.; Goyette, Thomas M.; Slingerland, Elizabeth J.; Giles, Robert H.; Nixon, William E.

2013-05-01

Remote sensing over long path lengths has become of greater interest in the terahertz frequency region. Applications such as pollution monitoring and detection of energetic chemicals are of particular interest. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum is lacking. The water vapor continuum absorption spectrum was investigated using Fourier Transform Spectroscopy. The continuum effect gives rise to an excess absorption that is unaccounted for in just a resonant line spectrum simulation. The transmission of broadband terahertz radiation from 0.300THz - 1.5THz through air with varying relative humidity levels was recorded for multiple path lengths. From these data, the absorption coefficient as a function of frequency was determined and compared with model calculations. The intensity and location of the strong absorption lines were in good agreement with spectral databases such as the 2008 HITRAN database and the JPL database. However, a noticeable continuum effect was observed particularly in the atmospheric transmission windows. A small discrepancy still remained even after accounting for continuum absorption using the best available data from the literature. This discrepancy, when projected over a one kilometer path length, typical of distances used in remote sensing, can cause a 30dB difference between calculated and observed attenuation. From the experimental and resonant line simulation spectra the air-broadening continuum parameter was calculated and compared with values available in the literature.

Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

PubMed Central

Secomb, Josh L.; Nimphius, Sophia; Farley, Oliver R.L.; Lundgren, Lina E.; Tran, Tai T.; Sheppard, Jeremy M.

2015-01-01

The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified between the thickness of the vastus lateralis (VL) and lateral gastrocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle. Key points Greater thickness of the VL and LG muscles were significantly related to an enhanced ability to express higher levels of isometric and dynamic strength, and explosiveness in adolescent athletes. Isometric strength underpinned performance in the CMJ and SJ in these athletes. Greater lower-body isometric strength was significantly related to eccentric leg stiffness, which is potentially the result of greater neuromuscular activation in the muscle-tendon unit. PMID:26664263

Diffusion Properties and 3D Architecture of Human Lower Leg Muscles Assessed with Ultra-High-Field-Strength Diffusion-Tensor MR Imaging and Tractography: Reproducibility and Sensitivity to Sex Difference and Intramuscular Variability.

PubMed

Fouré, Alexandre; Ogier, Augustin C; Le Troter, Arnaud; Vilmen, Christophe; Feiweier, Thorsten; Guye, Maxime; Gondin, Julien; Besson, Pierre; Bendahan, David

2018-05-01

Purpose To demonstrate the reproducibility of the diffusion properties and three-dimensional structural organization measurements of the lower leg muscles by using diffusion-tensor imaging (DTI) assessed with ultra-high-field-strength (7.0-T) magnetic resonance (MR) imaging and tractography of skeletal muscle fibers. On the basis of robust statistical mapping analyses, this study also aimed at determining the sensitivity of the measurements to sex difference and intramuscular variability. Materials and Methods All examinations were performed with ethical review board approval; written informed consent was obtained from all volunteers. Reproducibility of diffusion tensor indexes assessment including eigenvalues, mean diffusivity, and fractional anisotropy (FA) as well as muscle volume and architecture (ie, fiber length and pennation angle) were characterized in lower leg muscles (n = 8). Intramuscular variability and sex differences were characterized in young healthy men and women (n = 10 in each group). Student t test, statistical parametric mapping, correlation coefficients (Spearman rho and Pearson product-moment) and coefficient of variation (CV) were used for statistical data analysis. Results High reproducibility of measurements (mean CV ± standard deviation, 4.6% ± 3.8) was determined in diffusion properties and architectural parameters. Significant sex differences were detected in FA (4.2% in women for the entire lower leg; P = .001) and muscle volume (21.7% in men for the entire lower leg; P = .008), whereas architecture parameters were almost identical across sex. Additional differences were found independently of sex in diffusion properties and architecture along several muscles of the lower leg. Conclusion The high-spatial-resolution DTI assessed with 7.0-T MR imaging allows a reproducible assessment of structural organization of superficial and deep muscles, giving indirect information on muscle function. © RSNA, 2018 Online supplemental material is available for this article.

Evaluation of Serial Casting for Boys with Duchenne Muscular Dystrophy: A Case Report.

PubMed

Carroll, Kate; de Valle, Katy; Kornberg, Andrew; Ryan, Monique; Kennedy, Rachel

2018-02-01

To report the effects of below-knee serial casting in two boys with Duchenne muscular dystrophy who presented with well-preserved strength and calf shortening. Bilateral below-knee serial casts were applied over two weeks with follow-up of daily stretching and wearing of customized night splints. Outcome measures were performed at baseline, 1, 3, 6, and 12 months post-casting. These included measures of calf length, leg strength, motor function, endurance, and spatio-temporal gait parameters. Both boys completed serial casting with gains in muscle length. No adverse effects on strength or motor function were observed over a 12-month follow-up period.

Dynamically Stable Legged Locomotion

DTIC Science & Technology

1989-09-01

length during overground locomotion: task-specific modulation of the locomotor synergy. Journal of Experimental Psychology, 15(3). Raibert, M. I. 1986...energy conversions that intermediates between combus- tion of a fluid fuel such as gasoline , and the controlled delivery of force and power to the...question of this study: Can the extremely high energy density and rapid response of combustible fluid fuels such as gasoline be harnessed to produce

Differences in morphology and force/velocity relationship between Senegalese and Italian sprinters.

PubMed

Rahmani, Abderrehmane; Locatelli, Elio; Lacour, Jean-Rene

2004-04-01

In order to investigate whether the supremacy of African sprinters is related to the leg extensor force/velocity relationship or to leg morphology, two groups of elite sprinters originating respectively from Senegal (S) and Italy (I) were compared in this respect. The groups included 13 S and 15 I male sprinters. Their mean best performances over 100 m during the preceding track and field season were 10.66 (0.3) and 10.61 (0.3) s (NS), respectively. Age, height and mass were similar in the two groups. The force/velocity relationship of the leg extensors was assessed during maximal half-squats on a guided horizontal barbell with masses of 20-140 kg added on the shoulders. Leg morphology was assessed by relating the sub-ischial length to the standing height (L/H) and by measuring the inertia in the vertical (IZ in kg.cm2), antero-posterior (IY, kg.cm2) and medio-lateral (IX, kg.m2) planes. The two groups developed non-different force and power when lifting the heaviest loads. Inversely, the lighter the load, the lower the force and power developed by S, as compared to I (P<0.001). S demonstrated greater L/H (P<0.001), and 26% lower IZ (P<0.01), 15% lower IY (P=0.09), and 14% lower IX (P=0.10). These results suggest that S and I sprinters were similar as regards the muscle abilities involved in slow maximal contractions. However, S demonstrated lower values in muscle abilities related to high-speed contractions, suggesting that S sprinters had a lower percentage of fast twitch fibres. This is likely to be compensated for by the lower level of internal work due to longer and lighter legs.

The effects of dance training program on the postural stability of middle aged women.

PubMed

Kostić, Radmila; Uzunović, Slavoljub; Purenović-Ivanović, Tijana; Miletić, Đurđica; Katsora, Georgija; Pantelić, Saša; Milanović, Zoran

2015-11-01

The aim of the study was to determine the effects of Greek folk dancing on postural stability in middle age women. Sixty-three women aged from 47-53 participated in this study. All participants were randomly divided into the experimental group - 33 participants (mean ± SD; body height=160.13 ± 12.07 cm, body mass=63.81 ± 10.56 kg), and the control group - 30 participants (mean ± SD; body height=160.63 ± 6.22 cm, body mass=64.79 ± 8.19 kg). The following tests were used to evaluate the motor balance and posture stability of participants; the double-leg stance along the length of a balance beam (eyes open), the double-leg stance along the width of a balance beam (eyes open), the single-leg stance (eyes open) and the double-leg stance on one's toes (eyes closed). The Functional Reach Test for balance and the Star Excursion Balance Test were used to evaluate dynamic balance. The multivariate analysis of covariance of static and dynamic balance between participants of the experimental and control group at the final measuring, with neutralized differences at the initial measuring (Wilks' λ=0.45), revealed a significant difference (p<0.05). The intergroup difference at the final measuring was also found to be significant (p<0.05) for the following variables; the double-leg stance on one's toes, the Functional Reach Test, balance of the right anterolateral, balance of the right posterolateral and balance of the left posteromedial. An organized dance activity programme does lead to the improvement of static and dynamic balance in middle aged women. Copyright© by the National Institute of Public Health, Prague 2015.

A flight-phase terrain following control strategy for stable and robust hopping of a one-legged robot under large terrain variations.

PubMed

Shemer, Natan; Degani, Amir

2017-08-04

This work demonstrates a simple, once per step, flight-control method for robots running on a planar unknown rough-terrain environment. The robot used to exemplify these control strategies is the ParkourBot, a spring loaded inverted pendulum (SLIP)-based robot. The SLIP model is widely used for the description of humans and animals running motion and has been the basis for many robots. A known control scheme for increasing robustness of the conservative, SLIP model is the swing leg retraction (SLR) method. Despite of the SLR's popularity, it is not intended to be used on the more realistic, non-conservative damped SLIP model. On the damped SLIP model, the SLR controller failed to provide adequate results, therefore, we have derived a new simple, flight-phase control method called polynomial energy insertion (PEI). The new PEI method is based on the dead-beat solution of the damped simplified instantaneous SLIP (iSLIP) model, which assumes an infinitely stiff spring. Unlike the SLR which, starting from apex, changes the leg angle monotonically during flight, the PEI requires the leg length (hence, energy insertion) to change monotonically throughout the flight phase. Interestingly, the leg angle remains nearly constant. In simulations and experiments, we have compared the newly developed PEI to the previous SLR method. We have found that since the SLR does not control the horizontal velocity, it looses its stability under rough terrain. The PEI method was able to control the horizontal velocity and height from ground and hence showed great improvement in robustness to rough terrain. Moreover, in both simulations and experiments the PEI methods showed an increase in the mean jumps to failure of more than 30% compared to SLR-based controllers.

How performing a repetitive one-legged stance modifies two-legged postural control.

PubMed

Burdet, Cyril; Vuillerme, Nicolas; Rougier, Patrice R

2011-10-01

The proprioceptive cues in the control of movement is recognized as playing a major role in postural control. However, little is known about its possible increased contribution to postural control consecutive to repetitive muscular activations. To test this, the short-term effects induced by a 1-legged exercise on 2-legged postural control with the eyes closed were assessed in healthy subjects. The center-of-pressure (CP) displacements obtained using a force platform were split into 2 elementary movements: center-of-gravity vertical projection (CGv) and the difference (CP - CGv). These movements assessed the net postural performance and the level of neuromuscular activity, respectively, and were processed afterward (a) through variances, mean velocity, and the average surface covered by the trajectories and (b) a fractional Brownian motion (fBm) modeling. The latter provides further information about how much the subject controls the movements and the spatiotemporal relation between the successive control mechanisms. No difference was found using the classical parameters. In contrast, fBm parameters showed statistically significant changes in postural control after 1-legged exercises: The spatial and temporal coordinates of the transition points for the CG movements along the anteroposterior axis are decreased. Because the body movement control does not rely on visual or vestibular cues, this ability to trigger the corrective process of the CG movements more quickly in the postexercise condition and once a more reduced distance has been covered emphasizes how prior muscular activation improves body movement detection. As a general rule, these data show that the motor systems control body motions better after repetitive stimulation of the sensory cues. These insights should be of interest in physical activities based on a precise muscular length control.

Pain, not structural impairments may explain activity limitations in people with gluteal tendinopathy or hip osteoarthritis: A cross sectional study.

PubMed

Fearon, Angela; Neeman, Teresa; Smith, Paul; Scarvell, Jennie; Cook, Jill

2017-02-01

What are the functional differences between people with greater trochanteric pain syndrome (GT), hip osteoarthritis (OA) or an asymptomatic population as measured by walking, Time Up and Go, single leg standing and strength? Cross sectional study with blinded measurers. 38 participants with GT, 20 with end stage hip OA and 21 asymptomatic healthy control (AS) participants. All participants were women. Pain (numeric rating scale), Walking speed (m/s), cadence (steps/min) and step length (m) measured via the 10m walk test and the Timed Up and Go; balance via single leg stance (s) duration; and hip abduction, adduction, medial and lateral rotation strength, standardized to body mass (BM) via the body mass average index (BMavg), measured via a wall mounted dynamometer. The two symptomatic groups reported similar pain levels (p=0.226), more pain then the AS group (p<0.000). Compared to the AS participants, participants with GT or hip OA demonstrated lower walking speed (10mwt and TUG, p<0.001), lower cadence and shorter duration single leg stance on the affected leg (p<0.05). Participants with GT or hip OA also demonstrated bilaterally weaker hip abduction than the AS group (p≤0.005). Compared to AS and GT participants, participants with hip OA demonstrated adduction weakness on the affected side (p=0.008 and p=0.002 respectively). There is a significant level of dysfunction and impairments associated with GT and hip OA. As activity limitations do not appear to be differentiated by structural impairments, we suggest that pain, rather than the underlying pathology may be the driving impairment that leads to walking and single leg standing dysfunction. Copyright © 2016 Elsevier B.V. All rights reserved.

Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

PubMed

Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

2014-08-01

Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

The Effects of Leg Kick on Swimming Speed and Arm-Stroke Efficiency in the Front Crawl.

PubMed

Silveira, Ricardo Peterson; de Souza Castro, Flávio Antônio; Figueiredo, Pedro; Vilas-Boas, João Paulo; Zamparo, Paola

2017-07-01

To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed. Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect "paddle-wheel" approach in 3 different ways: using general, individual, and no adjustments to AC. The LC increased with SF (and speed) from -1% ± 4% to 11% ± 1% (P < .05). At the lower FCS speeds, ηF calculated using general adjustments was lower than ηF calculated using individual adjustments (P < .05), but differences disappear at the fastest speeds. Finally, ηF calculated using individual adjustments to LC in the FCS condition did not differ with ηF assessed in the SAO condition at all the investigated speeds. The relative contributions of the arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.

Dynamic legged locomotion in robots and animals

NASA Astrophysics Data System (ADS)

Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

1995-01-01

This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

The Relationship between Volume Conservation and a Volume Algorithm for a Rectangular Parallelepiped.

ERIC Educational Resources Information Center

Feghali, Issa Nehme

This study was designed to investigate the relationship between the level of conservation of displaced volume and the degree to which sixth-grade children learn the volume algorithm of a cuboid, namely, volume equals weight times length times height. The problem chosen is based on an apparent discrepancy between the present school programs and…

Maternity leave, women's employment, and marital incompatibility.

PubMed

Hyde, J S; Essex, M J; Clark, R; Klein, M H

2001-09-01

This research investigated the relationship between the length of women's maternity leave and marital incompatibility, in the context of other variables including the woman's employment, her dissatisfaction with the division of household labor, and her sense of role overload. Length of leave, work hours, and family salience were associated with several forms of dissatisfaction, which in turn predicted role overload. Role overload predicted increased marital incompatibility for experienced mothers but did not for first-time mothers, for whom discrepancies between preferred and actual child care were more important. Length of maternity leave showed significant interactions with other variables, supporting the hypothesis that a short leave is a risk factor that, when combined with another risk factor, contributes to personal and marital distress.

Behavioral ecology of black-legged kittiwakes during chick rearing in a failing colony

USGS Publications Warehouse

Roberts, Bay D.; Hatch, Scott A.

1993-01-01

Compared with their Atlantic counterparts, Black-legged Kittiwakes (Rissa tridactyla) in North Pacific colonies are notably unproductive. A large colony on Middleton Island, Alaska, has in most years since 1981 seen complete breeding failure and the population has declined by half. We compared parent-offspring behaviors in this colony during two years that differed in overall breeding success. Potential indicators of food stress included parental attendance at the nest, foraging trip lengths, chick feeding and begging rates, and sibling aggression. Whereas chick feeding and begging rates were strongly correlated with overall breeding performance, patterns of time allocation by adults (nest attendance and foraging trips) were not. Contrasts between years and comparisons with data from other colonies in and outside Alaska point to food shortage as the likely cause of recurrent breeding failure on Middleton.

Is increased residual shank length a competitive advantage for elite transtibial amputee long jumpers?

PubMed

Nolan, Lee; Patritti, Benjamin L; Stana, Laura; Tweedy, Sean M

2011-07-01

The purpose of this study was to evaluate the extent to which residual shank length affects long jump performance of elite athletes with a unilateral transtibial amputation. Sixteen elite, male, long jumpers with a transtibial amputation were videoed while competing in major championships (World Championships 1998, 2002 and Paralympic Games, 2004). The approach, take-off, and landing of each athlete's best jump was digitized to determine residual and intact shank lengths, jump distance, and horizontal and vertical velocity of center of mass at touchdown. Residual shank length ranged from 15 cm to 38 cm. There were weak, nonsignificant relationships between residual shank length and (a) distance jumped (r = 0.30), (b) horizontal velocity (r = 0.31), and vertical velocity (r = 0.05). Based on these results, residual shank length is not an important determinant of long jump performance, and it is therefore appropriate that all long jumpers with transtibial amputation compete in the same class. The relationship between residual shank length and key performance variables was stronger among athletes that jumped off their prosthetic leg (N = 5), and although this result must be interpreted cautiously, it indicates the need for further research.

Allometry in dinosaurs and mammals

NASA Astrophysics Data System (ADS)

Lee, Scott

2015-03-01

The proportions of the leg bones change as the size of an animal becomes larger since the mass of the animal increases at a faster rate than the cross-sectional area of its leg bones. For the case of elastic similarity (in which the longitudinal stress in the legs remains constant in animals of all sizes), the diameter d and length L of the femur should be related as d = A L3/2. For geometric similarity (in which all dimensions are scaled by the same factor), d = A L. For animals with femora longer than 20 cm, we find the power law relationship to be d = A Lb with b = 1.13 +/- 0.06 for extant mammals (the largest mammal being Loxodonta africana with a 1.00-m-long femur) and b = 1.18 +/- 0.02 for dinosaurs (the largest dinosaur being Brachiosaurus brancai with a 2.03-m-long femur). These data show that extinct dinosaurs and extant animals scale in the same basic manner. The large sauropods (with femora twice as long as found in elephants) scale in a manner consistent with extrapolation of the scaling shown by extant mammals. These results argue that extinct dinosaurs moved in a manner very similar to extant mammals.

Outbreak of encephalitic listeriosis in red-legged partridges (Alectoris rufa).

PubMed

Jeckel, S; Wood, A; Grant, K; Amar, C; King, S A; Whatmore, A M; Koylass, M; Anjum, M; James, J; Welchman, D de B

2015-01-01

An outbreak of neurological disease was investigated in red-legged partridges between 8 and 28 days of age. Clinical signs included torticollis, head tilt and incoordination and over an initial eight day period approximately 30-40 fatalities occurred per day. No significant gross post mortem findings were detected. Histopathological examination of the brain and bacterial cultures followed by partial sequencing confirmed a diagnosis of encephalitis due to Listeria monocytogenes. Further isolates were obtained from follow-up carcasses, environmental samples and pooled tissue samples of newly imported day-old chicks prior to placement on farm. These isolates had the same antibiotic resistance pattern as the isolate of the initial post mortem submission and belonged to the same fluorescent amplified fragment length polymorphism (fAFLP) subtype. This suggested that the isolates were very closely related or identical and that the pathogen had entered the farm with the imported day-old chicks, resulting in disease manifestation in partridges between 8 and 28 days of age. Reports of outbreaks of encephalitic listeriosis in avian species are rare and this is to the best of our knowledge the first reported outbreak in red-legged partridges.

DO THE LEGS OF MAGNETIC CLOUDS CONTAIN TWISTED FLUX-ROPE MAGNETIC FIELDS?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Owens, M. J.

2016-02-20

Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs) characterized primarily by a smooth rotation in the magnetic field direction indicative of the presence of a magnetic flux rope. Energetic particle signatures suggest MC flux ropes remain magnetically connected to the Sun at both ends, leading to widely used model of global MC structure as an extended flux rope, with a loop-like axis stretching out from the Sun into the heliosphere and back to the Sun. The time of flight of energetic particles, however, suggests shorter magnetic field line lengths than such a continuous twisted flux ropemore » would produce. In this study, two simple models are compared with observed flux rope axis orientations of 196 MCs to show that the flux rope structure is confined to the MC leading edge. The MC “legs,” which magnetically connect the flux rope to the Sun, are not recognizable as MCs and thus are unlikely to contain twisted flux rope fields. Spacecraft encounters with these non-flux rope legs may provide an explanation for the frequent observation of non-MC ICMEs.« less

Design of Ski Boots for Alpine Ski Racing Based on Leg Frame of the Skier

NASA Astrophysics Data System (ADS)

Suzuki, Soichiro; Hayashi, Sueyoshi

A ski boot is important to make progress in ski turning technique as an interface between a skier and a ski. Especially in alpine ski races, suitability of design of the boots for racers becomes more important to achieve accurate and quick lean of the leg in ski turns. This study is aimed at building a new design concept of a ski boot that can improve the results of alpine ski races. In this paper, new design of an upper shell of a ski boot that was adjusted to the features of the frame of alpine ski racers was experimentally examined. As a result, it was demonstrated that a front and a rear part of the upper shell of a ski boot should be separately adjusted to the length of a shank of each player for well-balanced quick lean of the leg in the ski turn. Finally, the effect of new design of an upper shell was examined in giant slalom and slalom tests by Japanese alpine ski racers of the first rank. Consequently, the results showed that lean angle during turns was increased and finish time was shortened when the skiers wore the newly designed boots.

Two-stage knee arthrodesis with a modular intramedullary nail due to septic failure of revision total knee arthroplasty with extensor mechanism deficiency.

PubMed

Friedrich, Max J; Schmolders, Jan; Wimmer, Matthias D; Strauss, Andreas C; Ploeger, Milena M; Wirtz, Dieter C; Gravius, Sascha; Randau, Thomas M

2017-10-01

Periprosthetic joint infection is a serious complication and reconstruction after failed revision total knee arthroplasty with significant bone loss and compromised soft-tissues can be challenging. Objective of this study was to assess clinical and functional results, implant survival and infection recurrence rates in patients treated with two-stage arthrodesis after failed revision TKA with extensor mechanism deficiencies due to PJI, and to identify the factors that affect outcomes after surgery. Thirty seven patients with PJI treated within a two-stage exchange and reimplantation of an arthrodesis nail between 2008 and 2014 were included. Systemic and local risk factors were graded preoperatively according to McPherson et al. All patients were treated according to a structured treatment algorithm. Clinical and functional evaluation was performed using the Oxford Knee Score and the Visual Analogue Scale. Thirty two of 37 patients (86.5%) were graded as free of infection. Five patients (13.5%) had recurrent infection after arthrodesis with the need of revision surgery. Mean leg-length discrepancy was 2.2cm. The mean VAS for pain was three, the mean Oxford Knee Score was 38±9. Total implant survival at a 74month follow-up was 74.3% (95% CI: 45.4 to 91.1%), as determined by Kaplan-Meier survival curves. Local McPherson Score, as well as number of revisions was found to be of significant influence to the survival rate. Septic failure of revision knee arthroplasty can be effectively treated with two-stage arthrodesis using a modular intramedullary nail, providing a stable and painless limb with satisfactory functional results and acceptable infection eradication rates. Copyright © 2017 Elsevier B.V. All rights reserved.

[Interposition arthrodesis of the ankle].

PubMed

Vienne, Patrick

2005-10-01

Bony fusion of the ankle in a functionally favorable position for restitution of a painless weight bearing while avoiding a leg length discrepancy. Disabling, painful osteoarthritis of the ankle with extensive bone defect secondary to trauma, infection, or serious deformities such as congenital malformations or diabetic osteoarthropathies. Acute joint infection. Severe arterial occlusive disease of the involved limb. Lateral approach to the distal fibula. Fibular osteotomy 7 cm proximal to the tip of the lateral malleolus and posterior flipping of the distal fibula. Exposure of the ankle. Removal of all articular cartilage and debridement of the bone defect. Determination of the size of the defect and harvesting of a corresponding tricortical bone graft from the iliac crest. Also harvesting of autogenous cancellous bone either from the iliac crest or from the lateral part of the proximal tibia. Insertion of the tricortical bone graft and filling of the remaining defect with cancellous bone. Fixation with three 6.5-mm titanium lag screws. Depending on the extent of the defect additional stabilization of the bone graft with a titanium plate. Fixation of the lateral fibula on talus and tibia with two 3.5-mm titanium screws for additional support. Wound closure in layers. Split below-knee cast with the ankle in neutral position. Between January 2002 and January 2004 this technique was used in five patients with extensive bone defects (four women, one man, average age 57 years [42-77 years]). No intra- or early postoperative complications. The AOFAS (American Orthopedic Foot and Ankle Society) Score was improved from 23 points preoperatively to 76 points postoperatively (average follow-up time of 25 months). Two patients developed a nonunion and underwent a revision with an ankle arthrodesis nail. A valgus malposition after arthrodesis in one patient was corrected with a supramalleolar osteotomy.

Autosomal dominant frontonasal dysplasia (atypical Greig syndrome): Lessons from the Xt mutant mouse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunningham, M.L.; Nunes, M.E.

1994-09-01

Greig syndrome is the autosomal dominant association of mild hypertelorism, variable polysyndactyly, and normal intelligence. Several families have been found to have translocations or deletions of 7p13 interrupting the normal expression of GLI3 (a zinc finger, DNA binding, transcription repressor). Recently, a mutation in the mouse homologue of GLI3 was found in the extra-toes mutant mouse (Xt). The phenotypic features of this mouse model include mild hypertelorism, postaxial polydactyly of the forelimbs, preaxial polydactyly of the hindlimbs, and variable tibial hemimelia. The homozygous mutant Xt/Xt have severe frontonasal dysplasia (FND), polysyndactyly of fore-and hindlimbs and invariable tibial hemimelia. We havemore » recently evaluated a child with severe (type D) frontonasal dysplasia, fifth finger camptodactyly, preaxial polydactyly of one foot, and ispilateral tibial hemimelia. His father was born with a bifid nose, broad columnella, broad feet, and a two centimeter leg length discrepancy. The paternal grandmother of the proband is phenotypically normal; however, her fraternal twin died at birth with severe facial anomalies. The paternal great-grandmother of the proband is phenotypically normal however her niece was born with moderate ocular hypertelorism. This pedigree is suggestive of an autosomal dominant form of frontonasal dysplasia with variable expressivity. The phenotypic features of our case more closely resemble the Xt mouse than the previously defined features of Greig syndrome in humans. This suggests that a mutation in GLI3 may be responsible for FND in this family. We are currently using polymorphic dinucleotide repeat markers flanking GLI3 in a attempt to demonstrate linkage in this pedigree. Demonstration of a GLI3 mutation in this family would broaden our view of the spectrum of phenotypes possible in Greig syndrome and could provide insight into genotype/phenotype correlation in FND.« less

Prophylactic titanium elastic nailing (TEN) following femoral lengthening (Lengthening then rodding) with one or two nails reduces the risk for secondary interventions after regenerate fractures: a cohort study in monolateral vs. bilateral lengthening procedures

PubMed Central

2013-01-01

Background Femoral fracture rates of up to 30% have been reported following lengthening procedures using fixators. “Lengthening then rodding” uses one or two titanium elastic nails (TENs) for prophylactic intramedullary nailing to reduce this complication. The aim of the study was to decide if usage of only one TEN is safe or has it a higher risk of getting a fracture? And we asked if there is a difference between patients with monolateral or bilateral lengthening procedures according to their fracture rate? Methods One or two TENs were implanted in two groups of patients (monolateral and bilateral) after femoral lengthening procedures. The regenerate quality was classified using the Li system and fractures were categorized using the Simpson and Kenwright classification. The follow-up period was at least 1 year after removal of the frame. Results Sixty-seven patients with 101 femoral lengthening procedures were included in 2007–2011. Group A included 34 patients with bilateral lengthening due to congenital short stature. Group B consisted of 33 patients with congenital disorders with leg length discrepancies. Seven fractures in six patients were seen in group A and five fractures in group B. One patient had residual shortening of 1 cm, and 11 fractures healed without relevant deviation (< 5°) or shortening (< 5 mm). A soft-tissue infection in one patient led to early removal of one TEN. Conclusions Fractures occurred in both groups of patients in total in 12 of the 101 cases (12%). The rate of secondary interventions was markedly reduced. Usage of one or two TENs did not influence the fracture rate. PMID:24156728

The radiological research for pelvis asymmetry of unilateral developmental dysplasia of the hip in adult.

PubMed

Li, Ya-Min; Li, Jue-Hong; Li, Bin; Wang, Jia-Xing; Chen, Yun-Su

2016-12-01

To investigate whether adult patients with unilateral developmental dysplasia of the hip (UDDH) have pelvic asymmetry and what correlation existing between them. Methods: A total of 100 adult patients with UDDH were enrolled in the retrospective observational study in Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China, between January 2012 and February 2014. The anteroposterior pelvic radiographs were reviewed and the pelvic heights and ischium heights were measured and compared between the affected and non-affected sides to find out the relationship between the pelvic morphology and hip dysplasia. Results: The pelvic heights demonstrated significant differences between the non-affected side and the affected side in patients with Crowe type II-IV UDDH (p less than 0.05), but not in patients with Crowe type I UDDH (p=0.09). There were significant differences in the bilateral ischium heights in patients with Crowe type III and IV UDDH (p less than 0.05), but not in patients with Crowe type I and II UDDH (p=0.78, p=0.055). In addition, the degree of hip dysplasia was positively associated with the degrees of asymmetry of pelvis (r=0.78, p less than 0.001) and ischium (r=0.72, p less than 0.001) in UDDH patients. Conclusion: The pelvic asymmetry exists in adult patients with UDDH. In addition, the degree of asymmetry has correlation with the degree of hip dysplasia. We recommend that it should be taken more cautions to use teardrops and ischial tuberosity as anatomy landmarks to balance leg-length discrepancy for unilateral DDH patients in preoperative planning and total hip arthroplasty.

An E-learning Module on Chronic Low Back Pain in Older Adults: Effect on Medical Resident Attitudes, Confidence, Knowledge, and Clinical Skills.

PubMed

Jacobs, Zachary G; Elnicki, D Michael; Perera, Subashan; Weiner, Debra K

2018-01-05

To determine 1) the feasibility of implementing an e-learning module on chronic low back pain (CLBP) in an older adult into an existing internal medicine residency curriculum and 2) the impact of this module on resident attitudes, confidence, knowledge, and clinical skills relating to CLBP. Participants were assigned to complete either the online module (N = 73) or the Yale Office-based curriculum on CLBP (N = 70). Attitudes, confidence, and knowledge were evaluated pre- and postintervention via survey. A retrospective blinded chart review of resident clinic encounters was conducted, wherein diagnosis codes and physical exam documentation were rated as basic or advanced. There was no improvement in overall knowledge scores in either group (60% average on both metrics). There were tendencies for greater improvements in the intervention group compared with controls for confidence in managing fibromyalgia (2.4 to 2.9 vs 2.5 to 2.5, P = 0.06) and leg length discrepancy (1.8 to 2.5 vs 1.5 to 1.9, P = 0.05). Those exposed to the online module also showed an increase in the percentage of physical exam documentation rated as advanced following the intervention (13% to 32%, P = 0.006), whereas the control group showed no change (14% to 12%, P = 0.68). An online module on CLBP in the older adult was a feasible addition to an existing curriculum for internal medicine residents. The module positively and substantively impacted resident clinical behaviors, as evidenced by enhanced sophistication in physical exam documentation; it also was associated with improved confidence in certain aspects of chronic pain management. © 2018 American Academy of Pain Medicine. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.

PubMed

Satkunskiene, Danguole; Mickevicius, Mantas; Snieckus, Audrius; Kamandulis, Sigitas

2017-01-01

Knee pain without knee degenerative symptoms is a common phenomenon among young basketball players. The aim of this study was to identify factors predisposing young basketball players to suffer from knee pain. The study involved 20 male adolescent (14-15 years) basketball players who were divided into two equal groups based on knee pain symptoms. Legs torque was tested on an isokinetic dynamometer. The length, elongation and the cross-sectional area (CSA) of the patellar tendon were measured with ultrasonography. Quadriceps angle (Q-angle), knee valgus motion, and joint angular displacement in the sagittal plane were analyzed using video recording during countermovement jump. Ground reaction force was measured using a force platform. Knee pain (KP) participants had a significantly lower Q-angle (P=0.045) and lower maximum varus knee angle (P=0.035), and a greater knee inside displacement (P=0.039) during squat phase. In the KP group, the CSA at the top of the tendon was significantly greater than in the middle (P=0.006) and at the bottom (P=0.039). Absolute tendon stiffness (P=0.013) and Young's modulus (P=0.034) were significantly lower in the KP group compared with controls. Leg stiffness during landing was significantly greater in the control group (P=0.015). Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.

Energy expenditure of wheeling and walking during prosthetic rehabilitation in a woman with bilateral transfemoral amputations.

PubMed

Wu, Y J; Chen, S Y; Lin, M C; Lan, C; Lai, J S; Lien, I N

2001-02-01

To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations. Observational, single patient, descriptive. An 80-meter long rectangular hallway in a rehabilitation unit. A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit. The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation. Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge. People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.

A stratocumulus thermodynamic analysis: July 5 case study

NASA Technical Reports Server (NTRS)

Austin, Philip

1990-01-01

On July 5 (NCAR Electra flight 4, Mission 186-G) the Electra flew a single aircraft mission which consisted of cross and along-wind legs at 6 different altitudes between 10:43 to 16:00 PDT (17:43 to 23:00 GMT). The leg length was kept short (8 to 10 minutes) to permit maximum vertical resolution, and there were 8 soundings. Observer notes report a thin, solid stratocumulus cloud deck which gradually became more broken in the afternoon. Winds were from the north at 10 to 13/ms throughout the night. Sea surface temperature measurements and conservative variable analyses for several of the July 5 legs are presented. These results are preliminary to a study of the thermodynamic budget on July 5; they indicate that: the sea surface temperature dropped more than 1 K (from 17.3 to 15.9 C) over the course of the flight (18:01 and at 21:51 GMT); mixing lines for each of the horizontal subcloud legs show the effect of a strong north-south gradient in SST; and there is a clear demarcation over a transition of 5 to 10 km between air to the south and cooler, moister air to the north. The FSSP measurements indicate there are small clouds/scud 250 m below cloud base on the cold northern side of this transition. The transition is seen in the saturation point diagrams at 984, 959, and 946 mb. There is no corresponding change in the horizontal wind across the transition regions.

Alignment displacements of the solar optical telescope primary mirror

NASA Technical Reports Server (NTRS)

Medenica, W. V.

1978-01-01

Solar optical telescope is a space shuttle payload which is at the present time (1978) being planned. The selected alignment method for the telescope's primary mirror is such that the six inclined legs supporting the mirror are at the same time motorized alignment actuators, changing their own length according to the alignment requirement and command. The alignment displacements were described, including circumvention of some apparent NASTRAN limitations.

Defense Small Business Innovation Research Program (SBIR) FY 1984.

DTIC Science & Technology

1984-01-12

nuclear submarine non-metallic, light weight, high strength piping . Includes the development of adequate fabrication procedures for attaching pipe ...waste heat economizer methods, require development. Improved conventional and hybrid heat pipes and/or two phase transport devices 149 IF are required...DESCRIPTION: A need exists to conceive, design, fabricate and test a method of adjusting the length of the individual legs of nylon or Kevlar rope sling

Correlates of low back pain in a general population sample: a multidisciplinary perspective.

PubMed

Roncarati, A; McMullen, W

1988-06-01

This study identifies correlates of low back pain in a general population sample and defines a profile of subjects with low back pain. A multidisciplinary approach was employed that required surveying and physically assessing 674 subjects on 105 variables in biographical, anatomical, strength and flexibility measurement categories. No attempt was made to select subjects from specific occupational, age, athletic, psychological and anatomical groups or subjects with specific biographical features, which may have resulted in a sample that was atypical of the general population. The results of this study based on a causal comparative ex post facto research design corroborated selected findings of previous research conducted on nongeneral population samples. These findings include relationships between low back pain and age, body type, sex, stress, smoking, selected types of physical activity, occupation and previous injuries to the neck, shoulders, back and upper legs, as well as previous episodes of low back pain. Additional correlates of low back pain that were identified and have little or controversial review in the back literature include: delayed low back pain syndrome caused by abrupt changes in running frequency, Q angle, pes cavus, leg length (right and left), trunk length, genu recurvatum and multiplane strength and flexibility limitations in the hip joints.

Dynamic traversal of high bumps and large gaps by a small legged robot

NASA Astrophysics Data System (ADS)

Gart, Sean; Winey, Nastasia; de La Tijera Obert, Rafael; Li, Chen

Small animals encounter and negotiate diverse obstacles comparable in size or larger than themselves. In recent experiments, we found that cockroaches can dynamically traverse bumps up to 4 times hip height and gaps up to 1 body length. To better understand the physics that governs these locomotor transitions, we studied a small six-legged robot negotiating high bumps and large gaps and compared it to animal observations. We found that the robot was able to traverse bumps as large as 1 hip height and gaps as wide as 0.5 body length. For the bump, the robot often climbed over to traverse when initial body yaw was small, but was often deflected laterally and failed to traverse when initial body yaw was large. A simple locomotion energy landscape model explained these observations. For the gap, traversal probability decreased with gap width, which was well explained by a simple Lagrangian model of a forward-moving rigid body falling over the gap edge. For both the bump and the gap, animal performance far exceeded that of the robot, likely due to their relatively higher running speeds and larger rotational oscillations prior to and during obstacle traversal. Differences between animal and robot obstacle negotiation behaviors revealed that animals used active strategies to overcome potential energy barriers.

Estimation of turbulence characteristics of the low-level eyewall and outer-core regions in intense Hurricanes Allen (1980) and Hugo (1989)

NASA Astrophysics Data System (ADS)

Zhang, J. A.; Marks, F. D.; Montgomery, M.; Lorsolo, S.

2010-12-01

Turbulent transport processes in the atmospheric boundary layer play an important role in the intensification and maintenance of a hurricane vortex. However, direct measurement of turbulence in the hurricane boundary layer has been scarce. This study analyzes the flight-level data collected by research aircraft that penetrated the eyewalls of Category 5 Hurricane Hugo (1989) and Category 4 Hurricane Allen (1980) between 1 km and the sea surface. Momentum flux, turbulent kinetic energy (TKE) and vertical eddy diffusivity are estimated before and during the eyewall penetrations. Spatial scales of turbulent eddies are determined through spectral analysis. The turbulence parameters estimated for the eyewall penetration leg are found to be nearly an order of magnitude larger than those for the leg outside the eyewall at similar altitudes. In the low-level intense eyewall region, the horizontal length scale of dominant turbulent eddies is found to be between 500 - 3000 m and the corresponding vertical length scale is approximately 100 - 200 m. The results suggest also that it is unwise to include the eyewall vorticity maximum (EVM) in the turbulence parameter estimation, since the EVMs are likely to be quasi two-dimensional vortex structures that are embedded within the three dimensional turbulence on the inside edge of the eyewall.

Association between maternal education and blood pressure: mediation evidence through height components in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

Rodríguez López, Santiago; Bensenor, Isabela M; Giatti, Luana; Molina, Maria Del Carmen; Lotufo, Paulo A

2017-05-01

Maternal education influences skeletal growth and offspring adult blood pressure (BP). Height components are negatively associated with BP in high-income countries. To evaluate the association between maternal education and offspring adult systolic and diastolic BP (SBP/DBP), assessing whether different height components might mediate such an association. Simple mediation modelling was used to evaluate the maternal education-offspring SBP/DBP association, estimating the contribution of offspring height components, in a cross-sectional sample of 13 571 Brazilians aged 34-75 from the ELSA-Brasil study. After full adjustment for confounders, and compared to participants whose mothers received low education, those whose mothers received high education had, on average, 0.2 mm Hg lower SBP (95% CI = -0.274, -0.132), as result of the link between maternal education and offspring adult height which, in turn, influenced SBP. Thus, 18-26% of the maternal education-SBP association occurred indirectly, through height, trunk and leg length, alternatively. Better maternal education might influence higher leg and trunk lengths in offspring, which, in turn, might contribute to prevent higher BP in adults. The negative height-BP association reported in high-income countries is also present in a middle-income country with more recent economic development.

Lower-body determinants of running economy in male and female distance runners.

PubMed

Barnes, Kyle R; Mcguigan, Michael R; Kilding, Andrew E

2014-05-01

A variety of training approaches have been shown to improve running economy in well-trained athletes. However, there is a paucity of data exploring lower-body determinants that may affect running economy and account for differences that may exist between genders. Sixty-three male and female distance runners were assessed in the laboratory for a range of metabolic, biomechanical, and neuromuscular measures potentially related to running economy (ml·kg(-1)·min(-1)) at a range of running speeds. At all common test velocities, women were more economical than men (effect size [ES] = 0.40); however, when compared in terms of relative intensity, men had better running economy (ES = 2.41). Leg stiffness (r = -0.80) and moment arm length (r = 0.90) were large-extremely largely correlated with running economy and each other (r = -0.82). Correlations between running economy and kinetic measures (peak force, peak power, and time to peak force) for both genders were unclear. The relationship in stride rate (r = -0.27 to -0.31) was in the opposite direction to that of stride length (r = 0.32-0.49), and the relationship in contact time (r = -0.21 to -0.54) was opposite of that of flight time (r = 0.06-0.74). Although both leg stiffness and moment arm length are highly related to running economy, it seems that no single lower-body measure can completely explain differences in running economy between individuals or genders. Running economy is therefore likely determined from the sum of influences from multiple lower-body attributes.

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication.

PubMed

Konik, Anita; Kuklewicz, Stanisław; Rosłoniec, Ewelina; Zając, Marcin; Spannbauer, Anna; Nowobilski, Roman; Mika, Piotr

2016-01-01

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p < 0.05) and extended step length (p < 0.05). PFWT increased by 96% (p < 0.05). MWT increased by 100% (p < 0.05). After completing the training, patients' gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p < 0.05) for both legs. No statistically significant relation between the post-training improvement of PFWT and MWT and step length increase and decreased frequency of step cycle was observed (p > 0.05). Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Multi-slice MRI reveals heterogeneity in disease distribution along the length of muscle in Duchenne muscular dystrophy.

PubMed

Chrzanowski, Stephen M; Baligand, Celine; Willcocks, Rebecca J; Deol, Jasjit; Schmalfuss, Ilona; Lott, Donovan J; Daniels, Michael J; Senesac, Claudia; Walter, Glenn A; Vandenborne, Krista

2017-09-01

Duchenne muscular dystrophy (DMD) causes progressive pathologic changes to muscle secondary to a cascade of inflammation, lipid deposition, and fibrosis. Clinically, this manifests as progressive weakness, functional loss, and premature mortality. Though insult to whole muscle groups is well established, less is known about the relationship between intramuscular pathology and function. Differences of intramuscular heterogeneity across muscle length were assessed using an ordinal MRI grading scale in lower leg muscles of boys with DMD and correlated to patient's functional status. Cross sectional T 1 weighted MRI images with fat suppression were obtained from ambulatory boys with DMD. Six muscles (tibialis anterior, extensor digitorum longus, peroneus, soleus, medial and lateral gastrocnemii) were graded using an ordinal grading scale over 5 slice sections along the lower leg length. The scores from each slice were combined and results were compared to global motor function and age. Statistically greater differences of involvement were observed at the proximal ends of muscle compared to the midbellies. Multi-slice assessment correlated significantly to age and the Vignos functional scale, whereas single-slice assessment correlated to the Vignos functional scale only. Lastly, differential disease involvement of whole muscle groups and intramuscular heterogeneity were observed amongst similar age subjects. A multi-slice ordinal MRI grading scale revealed that muscles are not uniformly affected, with more advanced disease visible near the tendons in a primarily ambulatory population with DMD. A geographically comprehensive evaluation of the heterogeneously affected muscle in boys with DMD may more accurately assess disease involvement.

Application of monorail fixator for femoral gap nonunion.

PubMed

Agrawal, Hemendra-Kumar; Jaiman, Ashish; Khatkar, Vipin; Sharma, Vinod-Kumar

2014-01-01

Difficult femoral nonunion takes account of infective nonunion and aseptic gap nonunion. Limb length discrepancy and nonunion need to be tackled simultaneously. Conventionally Ilizarov ring fixator is in vogue but it has some limitations. To overcome these, monorail fixator is an effective alternative. Persistent good results can be obtained if we can get a perfect anatomical alignment and good regeneration.

Pearls and pitfalls of deformity correction and limb lengthening via monolateral external fixation.

PubMed Central

Noonan, K. J.; Price, C. T.

1996-01-01

In conclusion, monolateral external fixation can be effectively utilized in the management of limb length discrepancy and angular deformity. This manuscript outlines the pertinent theory, application and problems important in these cases. When faced with specific congenital conditions the surgeon is encouraged to reference relevant literature that is more focused than the current paper. PMID:9129275

Influence of Sub-Daily Variation on Multi-Fractal Detrended Fluctuation Analysis of Wind Speed Time Series

PubMed Central

Li, Weinan; Kong, Yanjun; Cong, Xiangyu

2016-01-01

Using multi-fractal detrended fluctuation analysis (MF-DFA), the scaling features of wind speed time series (WSTS) could be explored. In this paper, we discuss the influence of sub-daily variation, which is a natural feature of wind, in MF-DFA of WSTS. First, the choice of the lower bound of the segment length, a significant parameter of MF-DFA, was studied. The results of expanding the lower bound into sub-daily scope shows that an abrupt declination and discrepancy of scaling exponents is caused by the inability to keep the whole diel process of wind in one single segment. Additionally, the specific value, which is effected by the sub-daily feature of local meteo-climatic, might be different. Second, the intra-day temporal order of wind was shuffled to determine the impact of diel variation on scaling exponents of MF-DFA. The results illustrate that disregarding diel variation leads to errors in scaling. We propose that during the MF-DFA of WSTS, the segment length should be longer than 1 day and the diel variation of wind should be maintained to avoid abnormal phenomena and discrepancy in scaling exponents. PMID:26741491

DKA, CVL and DVT. Increased risk of deep venous thrombosis in children with diabetic ketoacidosis and femoral central venous lines.

PubMed

Davis, J; Surendran, T; Thompson, S; Corkey, C

2007-01-01

Incidence of type 1 diabetes mellitus is continuing to rise in children. The presentation of diabetic ketoacidosis (DKA) in children with newly diagnosed diabetes is significantly higher in those less than 5 years old. Critically ill patients admitted to Paediatric Intensive Care Units (PICU), would have a central venous line (CVL) inserted as part of their ongoing management. There are associations linking with the development of deep venous thrombosis (DVT) in DKA/CVL patients. An 18-month-old boy presented with a short history of polydypsia, polyuria and weight loss. The initial blood sugar was 27.0 mmol/L and a venous blood gas showed severe metabolic acidosis. He was diagnosed and treated for DKA. He was transferred to the regional PICU for further management. There, a central venous line (CVL) was inserted in his left femoral vein. This was removed on Day 4. Subsequently, he developed a swelling on his left leg, with significant discrepancy in leg circumference. Doppler ultrasound confirmed a deep venous thrombosis. Conclusion Diabetes has a propensity for hypercoagulability and DKA promotes a prothrombotic state. Retrospective studies have shown younger patients with DKA and a femoral CVL are at higher risk of developing DVT. A central femoral line should avoided in such patients. DVT prophylaxis and Doppler follow up should also be considered.

Review and clinal variation of New Zealand Anabaxis Raffray (Coleoptera: Staphylinidae: Pselaphinae: Goniaceritae).

PubMed

Shen, Jia-Wei; Leschen, Richard A B

2018-02-21

The New Zealand members of the genus Anabaxis Raffray are revised to accommodate three species, including one new species: Anabaxis chathamensis sp. nov. A key and an illustrated catalogue to the described species from New Zealand and Australia are included. Lectotypes are designated for A. brevis Oke, A. electrica King, A. foveolata Broun, A. inusitata Blackburn, A. lunatica King, A. quinquefoveolata Raffray, and A. vagus Oke. The widespread New Zealand species A. foveolata exhibits an unusual form of clinal variation in sex-linked characters of the male legs. The length of the tibial spine increased with increasing latitude and the length of the mesotrochanteral spine decreased with increasing latitude.

Correlation lengths in hydrodynamic models of active nematics.

PubMed

Hemingway, Ewan J; Mishra, Prashant; Marchetti, M Cristina; Fielding, Suzanne M

2016-09-28

We examine the scaling with activity of the emergent length scales that control the nonequilibrium dynamics of an active nematic liquid crystal, using two popular hydrodynamic models that have been employed in previous studies. In both models we find that the chaotic spatio-temporal dynamics in the regime of fully developed active turbulence is controlled by a single active scale determined by the balance of active and elastic stresses, regardless of whether the active stress is extensile or contractile in nature. The observed scaling of the kinetic energy and enstrophy with activity is consistent with our single-length scale argument and simple dimensional analysis. Our results provide a unified understanding of apparent discrepancies in the previous literature and demonstrate that the essential physics is robust to the choice of model.

Mechanics of jumping on water

NASA Astrophysics Data System (ADS)

Kim, Ho-Young; Amauger, Juliette; Jeong, Han-Bi; Lee, Duck-Gyu; Yang, Eunjin; Jablonski, Piotr G.

2017-10-01

Some species of semiaquatic arthropods including water striders and springtails can jump from the water surface to avoid sudden dangers like predator attacks. It was reported recently that the jump of medium-sized water striders is a result of surface-tension-dominated interaction of thin cylindrical legs and water, with the leg movement speed nearly optimized to achieve the maximum takeoff velocity. Here we describe the mathematical theories to analyze this exquisite feat of nature by combining the review of existing models for floating and jumping and the introduction of the hitherto neglected capillary forces at the cylinder tips. The theoretically predicted dependence of body height on time is shown to match the observations of the jumps of the water striders and springtails regardless of the length of locomotory appendages. The theoretical framework can be used to understand the design principle of small jumping animals living on water and to develop biomimetic locomotion technology in semiaquatic environments.

USE OF GLUE-ON SHOES TO IMPROVE CONFORMATIONAL ABNORMALITIES IN TWO ASIAN ELEPHANTS ( ELEPHAS MAXIMUS).

PubMed

Johnson, Gary; Smith, Joanne; Peddie, Jim; Peddie, Linda; DeMarco, Joe; Wiedner, Ellen

2018-03-01

This report describes the use of custom-made, glue-on shoes for the front feet of two female adult Asian elephants ( Elephas maximus) with conformational abnormalities. Both elephants had unequal leg lengths. The first elephant also had bilateral fetlock varus causing recurrent nail infections of the fourth digits of the front feet. The second elephant displayed weight shifting. Over several years, multiple shoe prototypes were tested. The current version is made of two types of shoe rubber, glued together and attached to the pad of the shorter leg with a liquid adhesive. The first elephant also has bilateral wedge pads to offload pressure from the fourth nails. The shoes are removed each month for foot care, then replaced. Within several months of wearing shoes, the first elephant's nail infections healed and the second elephant stopped weight shifting. Both elephants' gaits became smoother. This is the first description of corrective shoeing in elephants.

Lower Limb Rehabilitation Using Patient Data

PubMed Central

Saadat, Mozafar

2016-01-01

The aim of this study is to investigate the performance of a 6-DoF parallel robot in tracking the movement of the foot trajectory of a paretic leg during a single stride. The foot trajectories of nine patients with a paretic leg including both males and females have been measured and analysed by a Vicon system in a gait laboratory. Based on kinematic and dynamic analysis of a 6-DoF UPS parallel robot, an algorithm was developed in MATLAB to calculate the length of the actuators and their required forces during all trajectories. The workspace and singularity points of the robot were then investigated in nine different cases. A 6-DoF UPS parallel robot prototype with high repeatability was designed and built in order to simulate a single stride. Results showed that the robot was capable of tracking all of the trajectories with the maximum position error of 1.2 mm. PMID:27721648

A CONTROLLED TECHNIQUE FOR VEIN STRIPPING

PubMed Central

Gordon, Milton; Payne, Robert D.

1953-01-01

A number of difficulties encountered in vein stripping operations for varicose veins in the legs have been overcome by use of a technique evolved by adaptation and modifications of various reported methods. The stripping instrument is passed from below upward, the valves or branches offering less impediment to its passage in that direction. Inserting the tip of the instrument at the ankle through an incision in the vein while it is still in continuity is easier than introducing it into the end of a transected vein. Ligation of major superficial branches or subfascial division of communicating veins can be readily carried out while the stripper is still in place in the vein. Applying pressure bandages to the entire length of the leg before removing the stripper and the telescoped vein diminishes the chances of ecchymosis yet does not hinder withdrawal of the instrument and the vein. PMID:13106726

An evaluation of water vapor radiometer data for calibration of the wet path delay in very long baseline interferometry experiments

NASA Technical Reports Server (NTRS)

Kuehn, C. E.; Himwich, W. E.; Clark, T. A.; Ma, C.

1991-01-01

The internal consistency of the baseline-length measurements derived from analysis of several independent VLBI experiments is an estimate of the measurement precision. The paper investigates whether the inclusion of water vapor radiometer (WVR) data as an absolute calibration of the propagation delay due to water vapor improves the precision of VLBI baseline-length measurements. The paper analyzes 28 International Radio Interferometric Surveying runs between June 1988 and January 1989; WVR measurements were made during each session. The addition of WVR data decreased the scatter of the length measurements of the baselines by 5-10 percent. The observed reduction in the scatter of the baseline lengths is less than what is expected from the behavior of the formal errors, which suggest that the baseline-length measurement precision should improve 10-20 percent if WVR data are included in the analysis. The discrepancy between the formal errors and the baseline-length results can be explained as the consequence of systematic errors in the dry-mapping function parameters, instrumental biases in the WVR and the barometer, or both.

Improved Training Method for Rapid Rehabilitation of Amputees

DTIC Science & Technology

2014-03-01

return to active duty or to a productive civilian life. Body This was the third year of a research effort to develop and test a novel training...a velocity standardized to leg length. This test assessment of the rehabilitative program is performed before and after the two week training on the...control group : Comparisons were also made between patients who had not been enrolled in the research study to patients who had participated in the

Experimental and numerical study of a 10MW TLP wind turbine in waves and wind

NASA Astrophysics Data System (ADS)

Pegalajar-Jurado, Antonio; Hansen, Anders M.; Laugesen, Robert; Mikkelsen, Robert F.; Borg, Michael; Kim, Taeseong; Heilskov, Nicolai F.; Bredmose, Henrik

2016-09-01

This paper presents tests on a 1:60 version of the DTU 10MW wind turbine mounted on a tension leg platform and their numerical reproduction. Both the experimental setup and the numerical model are Froude-scaled, and the dynamic response of the floating wind turbine to wind and waves is compared in terms of motion in the six degrees of freedom, nacelle acceleration and mooring line tension. The numerical model is implemented in the aero-elastic code Flex5, featuring the unsteady BEM method and the Morison equation for the modelling of aerodynamics and hydrodynamics, respectively. It was calibrated with the tests by matching key system features, namely the steady thrust curve and the decay tests in water. The calibrated model is used to reproduce the wind-wave climates in the laboratory, including regular and irregular waves, with and without wind. The model predictions are compared to the measured data, and a good agreement is found for surge and heave, while some discrepancies are observed for pitch, nacelle acceleration and line tension. The addition of wind generally improves the agreement with test results. The aerodynamic damping is identified in both tests and simulations. Finally, the sources of the discrepancies are discussed and some improvements in the numerical model are suggested in order to obtain a better agreement with the experiments.

Effects of hysteresis of static contact angle (HSCA) and boundary slip on the hydrodynamics of water striders

NASA Astrophysics Data System (ADS)

Zheng, J.; Wang, B. S.; Chen, W. Q.; Han, X. Y.; Li, C. F.; Zhang, J. Z.; Yu, K. P.

2017-02-01

It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed 23 cm\\cdot s^{-1}. As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as F˜ C1U+C2 U^{2+ɛ}, where C1 and C2 are determined by the dimple depth. Discrete points on this curve could give fitted relations as F˜ Ub (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.

Periodization effects during short-term resistance training with equated exercise variables in females.

PubMed

Pelzer, Thiemo; Ullrich, Boris; Pfeiffer, Mark

2017-03-01

During resistance training, volume and load can be altered either gradually (traditional periodization: TP) or with frequent changes between subsequent sessions (daily undulating periodization: DUP). We hypothesized that the periodization model employed would not impact upon training-induced adaptations when exercise variables are equated. Nineteen females (22.0 years, moderate resistance training experience of 27.9 months) performed 6 weeks of knee extensor training with 3 weekly sessions exercising one leg using TP and the contralateral leg using DUP. Training load varied between 40, 60, and 80% of one repetition maximum (1RM). Volume, range of motion, and time under tension were equated for each leg with a biofeedback software. Dynamometry, surface EMG and ultrasonography were used to determine temporal changes of knee extensor maximum voluntary strength (MVC), neural drive of the M. quadriceps femoris (QF) and vastus lateralis (VL) and rectus femoris (RF) muscle architecture. Significant (P < 0.05) gains for isometric (TP 15%, DUP 13%) and isokinetic-concentric (TP 8%, DUP 10%) MVC and knee extensor 1RM (TP 18%, DUP 24%) occurred post training. VL and RF-muscle thickness showed significant (P < 0.05) increases ranging from 12 to 20% for TP and from 13 to 19% for DUP. Furthermore, significant (P < 0.05) increases in VL-pennation angle and VL-fascicle length occurred in both legs while QF EMG remained unchanged. No significant temporal differences were found between both models, displaying similar small to large effect sizes. Periodization is no adaptation trigger during short-term resistance training with equated exercise variables.

Motor recovery of stroke patients after rehabilitation: one-year follow-up study.

PubMed

Kuptniratsaikul, Vilai; Kovindha, Apichana; Suethanapornkul, Sumalee; Massakulpan, Pornpimon; Permsirivanich, Wutichai; Kuptniratsaikul, Patcharawimol Srisa-An

2017-01-01

Purpose To investigate motor recovery of stroke patients 1 year after rehabilitation. Materials and Methods A cross-sectional study of 192 stroke patients discharged from rehabilitation wards in nine tertiary hospitals was conducted. Motor recovery was assessed using the Brunnstrom motor recovery stages (BMRS), at 6 and 12 months after discharge. Factors related to the BMRS of the hand, arm and leg were analyzed. Results The mean age of patients was 62.2 years (57.3% male). Significantly more patients presented improvement of at least one BMRS of the hand, arm and leg compared with those with decreasing BMRS (p < 0.001). The percentage of patients with BMRS III- VI at 6 months was greater than that at discharge, but the recovery at 12 months was slightly higher than that at 6 months. It seems that motor recovery from stroke was near maximal at six months. Regarding the factors related to motor recovery, only lengths of stay (LOS) <30 d during the first admission and Barthel index at discharge ≥10 were related to the improvement of BMRS of the hand, arm and leg on multivariate analysis. Additionally, no complication at discharge was associated with the improvement of BMRS of the leg. Conclusions Approximately half of our stroke patients had motor improvement of at least one stage of BMRS at one year. Motor recovery after stroke at the end of the first year was associated with shorter LOS during the first admission, higher discharge Barthel index score and absence of complications at discharge.

Nerve Conduction Study on Sural Nerve among Nepalese Tailors Using Mechanical Sewing Machine.

PubMed

Yadav, Prakash Kumar; Yadav, Ram Lochan; Sharma, Deepak; Shah, Dev Kumar; Thakur, Dilip; Limbu, Nirmala; Islam, Md Nazrul

2017-03-01

The use of new technologies and innovations are out of access for people living in a developing country like Nepal. The mechanical sewing machine is still in existence at a large scale and dominant all over the country. Tailoring is one of the major occupations adopted by skilled people with lower socioeconomic status and education level. Sural nerves of both right and left legs are exposed to strenuous and chronic stress exerted by chronic paddling of mechanical sewing machine with legs. To evaluate the influence of chronic and strenuous paddling on right and left sural nerves. The study recruited 30 healthy male tailors with median age {34(31-37.25)} years (study group), and, 30 healthy male volunteers with age {34(32-36.25)} years (control group). Anthropometric measurements (age, height, weight, BMI and length of both right and left legs) as well as cardio respiratory measurements [Systolic Blood Pressure (SBP), Dystolic Blood Pressure (DBP), Pules Rate (PR) and Respiratory Rate (RR)] were recorded for each subject. Standard nerve conduction techniques using constant measured distances were applied to evaluate sural nerve (sensory) in both legs of each individual. The differences in variables between the study and control groups were tested using Student's t-test for parametric variables and Mann-Whitney U test for nonparametric variables. A p-value of ≤ 0.05 was considered significant. Age, height, weight, body mass index and leg length were not significantly different between tailors and control groups. Cardio respiratory measurements (SBP, DBP, PR and RR) were also not significantly altered between both the groups. The sensory nerve conduction velocities (m/s) of the right {44.23(42.72-47.83) vs 50(46- 54)} and left sural nerves {45.97±5.86 vs 50.67±6.59} m/s were found significantly reduced in tailors in comparison to control group. Similarly amplitudes (μv) of right sural (20.75±5.42 vs 24.10±5.45) and left sural nerves {18.2(12.43-21.8) vs 32.0(26.5-35.25)} were significantly less in tailors in comparison to control group whereas, latencies (ms) of right sural {2.6(2.2-2.7) vs 2.0(2.0-2.250} and left sural nerve {2.4(2.07-2.72) vs 2.0(2.0-2.0)} were found significantly high in tailors as compared with control group. Operating mechanical sewing machine by paddling chronically and arduously could have attributed to abnormal nerve conduction study parameters due to vibration effect of the machine on right and left sural nerves. The results of present study follow the trend towards presymptomatic or asymptomatic neuropathy similar to subclinical neuropathy.

Nerve Conduction Study on Sural Nerve among Nepalese Tailors Using Mechanical Sewing Machine

PubMed Central

Yadav, Ram Lochan; Sharma, Deepak; Shah, Dev Kumar; Thakur, Dilip; Limbu, Nirmala; Islam, Md. Nazrul

2017-01-01

Introduction The use of new technologies and innovations are out of access for people living in a developing country like Nepal. The mechanical sewing machine is still in existence at a large scale and dominant all over the country. Tailoring is one of the major occupations adopted by skilled people with lower socioeconomic status and education level. Sural nerves of both right and left legs are exposed to strenuous and chronic stress exerted by chronic paddling of mechanical sewing machine with legs. Aim To evaluate the influence of chronic and strenuous paddling on right and left sural nerves. Materials and Methods The study recruited 30 healthy male tailors with median age {34(31-37.25)} years (study group), and, 30 healthy male volunteers with age {34(32-36.25)} years (control group). Anthropometric measurements (age, height, weight, BMI and length of both right and left legs) as well as cardio respiratory measurements [Systolic Blood Pressure (SBP), Dystolic Blood Pressure (DBP), Pules Rate (PR) and Respiratory Rate (RR)] were recorded for each subject. Standard nerve conduction techniques using constant measured distances were applied to evaluate sural nerve (sensory) in both legs of each individual. The differences in variables between the study and control groups were tested using Student’s t-test for parametric variables and Mann-Whitney U test for nonparametric variables. A p-value of ≤ 0.05 was considered significant. Results Age, height, weight, body mass index and leg length were not significantly different between tailors and control groups. Cardio respiratory measurements (SBP, DBP, PR and RR) were also not significantly altered between both the groups. The sensory nerve conduction velocities (m/s) of the right {44.23(42.72-47.83) vs 50(46- 54)} and left sural nerves {45.97±5.86 vs 50.67±6.59} m/s were found significantly reduced in tailors in comparison to control group. Similarly amplitudes (μv) of right sural (20.75±5.42 vs 24.10±5.45) and left sural nerves {18.2(12.43-21.8) vs 32.0(26.5-35.25)} were significantly less in tailors in comparison to control group whereas, latencies (ms) of right sural {2.6(2.2-2.7) vs 2.0(2.0-2.250} and left sural nerve {2.4(2.07-2.72) vs 2.0(2.0-2.0)} were found significantly high in tailors as compared with control group. Conclusion Operating mechanical sewing machine by paddling chronically and arduously could have attributed to abnormal nerve conduction study parameters due to vibration effect of the machine on right and left sural nerves. The results of present study follow the trend towards presymptomatic or asymptomatic neuropathy similar to subclinical neuropathy. PMID:28511376

A new species of Metacyclops Kiefer, 1927 (Copepoda, Cyclopidae, Cyclopinae) from the Chihuahuan desert, northern Mexico

PubMed Central

Mercado-Salas, Nancy F.; Suárez-Morales, Eduardo; Maeda-Martínez, Alejandro M.; Silva-Briano, Marcelo

2013-01-01

Abstract A new species of the freshwater cyclopoid copepod genus Metacyclops Kiefer, 1927 is described from a single pond in northern Mexico, within the binational area known as the Chihuahuan Desert. This species belongs to a group of Metacyclops species with a 3443 spine formula of swimming legs. It is morphologically similar to Metacyclops lusitanus Lindberg, 1961 but differs from this and other congeners by having a unique combination of characters, including a caudal rami length/width proportion of 3.5–3.8, a innermost terminal seta slightly longer than the outermost terminal seta, intercoxal sclerites of legs 1-4 naked, a strong apical spine of the second endopodal segment of leg 1 and one row of 6-8 small spinules at the insertion of this spine. The finding of this species represents also the first record of the genus in Mexico and the third in North America, where only two other species, Metacyclops gracilis (Lilljeborg, 1853)and Metacyclops cushae Reid, 1991 have been hitherto reported. This is also the first continental record of a species of Metacyclops from an arid environment in the Americas. This species appears to be endemic to the Chihuahuan Desert, thus emphasizing the high endemicity of this area. PMID:23794845

Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots

PubMed Central

Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

2014-01-01

Neurobiological studies have shown that insects are able to adapt leg movements and posture for obstacle negotiation in changing environments. Moreover, the distance to an obstacle where an insect begins to climb is found to be a major parameter for successful obstacle negotiation. Inspired by these findings, we present an adaptive neural control mechanism for obstacle negotiation behavior in hexapod robots. It combines locomotion control, backbone joint control, local leg reflexes, and neural learning. While the first three components generate locomotion including walking and climbing, the neural learning mechanism allows the robot to adapt its behavior for obstacle negotiation with respect to changing conditions, e.g., variable obstacle heights and different walking gaits. By successfully learning the association of an early, predictive signal (conditioned stimulus, CS) and a late, reflex signal (unconditioned stimulus, UCS), both provided by ultrasonic sensors at the front of the robot, the robot can autonomously find an appropriate distance from an obstacle to initiate climbing. The adaptive neural control was developed and tested first on a physical robot simulation, and was then successfully transferred to a real hexapod robot, called AMOS II. The results show that the robot can efficiently negotiate obstacles with a height up to 85% of the robot's leg length in simulation and 75% in a real environment. PMID:24523694

On Kiefer’s American Eucyclops (Copepoda, Eucyclopinae): redescriptions and comments on the historical records of E. delachauxi, E. prionophorus, E. bondi and E. leptacanthus

PubMed Central

Mercado-Salas, Nancy F.; Suárez-Morales, Eduardo

2014-01-01

Abstract The freshwater copepod genus Eucyclops contains many supposedly cosmopolitan species whose taxonomic status is still under discussion; some of them represent species complexes. The problem is not exclusive to these widespread species; there are several American Eucyclops needing a taxonomic re-evaluation. Based on the examination of Friedrich Kiefer’s collection in Karlsruhe, Germany, the type specimens of four American species of Eucyclops (E. delachauxi (Kiefer, 1926), E. prionophorus Kiefer, 1931, E. bondi Kiefer, 1934, E. leptacanthus Kiefer, 1956) were re-examined and redescribed using upgraded descriptive standards. Kiefer’s translated descriptions and unpublished original drawings of these species are also presented. Characters like the ornamentation of the antennal basis, ornamentation of intercoxal sclerites of the swimming legs 1–4, length of basipodal seta of leg 1, ornamentation of caudal rami, the presence of aesthetascs and modified setae on the antennules in male, and the structure of the male sixth leg are compared herein to aid a more accurate separation of these American species. A revision of the American records of these species confirms that some are likely to refer to undescribed species. Overall, the diversity of the American Eucyclops appears to be underestimated and certainly deserves further study. PMID:24843261

Adaptive, fast walking in a biped robot under neuronal control and learning.

PubMed

Manoonpong, Poramate; Geng, Tao; Kulvicius, Tomas; Porr, Bernd; Wörgötter, Florentin

2007-07-01

Human walking is a dynamic, partly self-stabilizing process relying on the interaction of the biomechanical design with its neuronal control. The coordination of this process is a very difficult problem, and it has been suggested that it involves a hierarchy of levels, where the lower ones, e.g., interactions between muscles and the spinal cord, are largely autonomous, and where higher level control (e.g., cortical) arises only pointwise, as needed. This requires an architecture of several nested, sensori-motor loops where the walking process provides feedback signals to the walker's sensory systems, which can be used to coordinate its movements. To complicate the situation, at a maximal walking speed of more than four leg-lengths per second, the cycle period available to coordinate all these loops is rather short. In this study we present a planar biped robot, which uses the design principle of nested loops to combine the self-stabilizing properties of its biomechanical design with several levels of neuronal control. Specifically, we show how to adapt control by including online learning mechanisms based on simulated synaptic plasticity. This robot can walk with a high speed (>3.0 leg length/s), self-adapting to minor disturbances, and reacting in a robust way to abruptly induced gait changes. At the same time, it can learn walking on different terrains, requiring only few learning experiences. This study shows that the tight coupling of physical with neuronal control, guided by sensory feedback from the walking pattern itself, combined with synaptic learning may be a way forward to better understand and solve coordination problems in other complex motor tasks.

Abnormal peri-pubertal anthropometric measurements and growth pattern in adolescent idiopathic scoliosis: a study of 598 patients.

PubMed

Siu King Cheung, Catherine; Tak Keung Lee, Warren; Kit Tse, Yee; Ping Tang, Sheng; Man Lee, Kwong; Guo, Xia; Qin, Lin; Chun Yiu Cheng, Jack

2003-09-15

A cross-sectional study of anthropometric parameters in adolescent idiopathic scoliosis (AIS). To compare anthropometric parameters and growth pattern of AIS girls versus normal controls during peri-puberty. Abnormal pattern of growth has been reported in AIS patients. The sequential changes of growth and the correlation with curve severity have not been properly studied. Five hundred ninety-eight AIS girls and 307 healthy girls entered the study. Weight, height, body mass index (BMI), arm span, sitting height, and leg length were determined using standard techniques. Height and sitting height were adjusted by using the greatest Cobb angle to correct for spinal deformity (Bjure's formula). Puberty was graded by Tanner's staging. AIS girls had significantly shorter height (P = 0.001), corrected height (P = 0.005), arm span (P = 0.022), sitting height (P = 0.005) and leg length (P = 0.004) than the controls at pubertal stage I. From pubertal stages II through V, corrected height (P

Normative Functional Performance Values in High School Athletes: The Functional Pre-Participation Evaluation Project.

PubMed

Onate, James A; Starkel, Cambrie; Clifton, Daniel R; Best, Thomas M; Borchers, James; Chaudhari, Ajit; Comstock, R Dawn; Cortes, Nelson; Grooms, Dustin R; Hertel, Jay; Hewett, Timothy E; Miller, Meghan Maume; Pan, Xueliang; Schussler, Eric; Van Lunen, Bonnie L

2018-01-01

  The fourth edition of the Preparticipation Physical Evaluation recommends functional testing for the musculoskeletal portion of the examination; however, normative data across sex and grade level are limited. Establishing normative data can provide clinicians reference points with which to compare their patients, potentially aiding in the development of future injury-risk assessments and injury-mitigation programs.   To establish normative functional performance and limb-symmetry data for high school-aged male and female athletes in the United States.   Cross-sectional study.   Athletic training facilities and gymnasiums across the United States.   A total of 3951 male and female athletes who participated on high school-sponsored basketball, football, lacrosse, or soccer teams enrolled in this nationwide study.   Functional performance testing consisted of 3 evaluations. Ankle-joint range of motion, balance, and lower extremity muscular power and landing control were assessed via the weight-bearing ankle-dorsiflexion-lunge, single-legged anterior-reach, and anterior single-legged hop-for-distance (SLHOP) tests, respectively. We used 2-way analyses of variance and χ 2 analyses to examine the effects of sex and grade level on ankle-dorsiflexion-lunge, single-legged anterior-reach, and SLHOP test performance and symmetry.   The SLHOP performance differed between sexes (males = 187.8% ± 33.1% of limb length, females = 157.5% ± 27.8% of limb length; t = 30.3, P < .001). A Cohen d value of 0.97 indicated a large effect of sex on SLHOP performance. We observed differences for SLHOP and ankle-dorsiflexion-lunge performance among grade levels, but these differences were not clinically meaningful.   We demonstrated differences in normative data for lower extremity functional performance during preparticipation physical evaluations across sex and grade levels. The results of this study will allow clinicians to compare sex- and grade-specific functional performances and implement approaches for preventing musculoskeletal injuries in high school-aged athletes.

A prospective randomized cost billing comparison of local fasciocutaneous perforator versus free Gracilis flap reconstruction for lower limb in a developing economy.

PubMed

Abdelrahman, Islam; Moghazy, Amr; Abbas, Ashraf; Elmasry, Moustafa; Adly, Osama; Elbadawy, Mohamed; Steinvall, Ingrid; Sjoberg, Folke

2016-08-01

Distal half leg complex wounds are usually a formidable problem that necessitates either local or free flap coverage. The aim of this study was to compare cost billing charges in free Gracilis flap (fGF) and local fasciocutaneous perforator flap (lFPF) in reconstructing complex soft tissue leg and foot defects. Thirty consecutive adult (>15-year-old) patients with soft tissue defects in the leg and/or foot requiring tissue coverage with a flap in the period between 2012 and 2015 were randomly assigned (block randomization) to either an fGF or lFPF procedure. The outcome measures addressed were total billed charges costs, perioperative billed charges cost, partial or complete flap loss, length of hospital stay, inpatient postsurgical care duration, complications, operating time and number of operative scrub staff. One patient suffered from complete flap loss in each group. Reconstruction with lFPF showed total lower billed charges costs by 62% (2509 USD) (p < 0.001) and perioperative billed charges cost by 54% (779 USD) (p < 0.001), and shorter total hospital stay (36.5 days; p < 0.001), inpatient postsurgical care duration (6.4 days; p < 0.001), operating time (4.3 h; p < 0.001) and fewer scrub staff (2.2 persons; p < 0.001). These results suggest that neither flap is totally superior to the other; the choice should instead be based on the outcome sought and logistics. lFPF requires lower billed charges cost and resource use and saves operative time and personnel and reduces length of hospital stay. Our approach changed towards using perforator flaps in medium-sized defects, keeping the free flap option for larger defects. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Treatment of achondroplasia with growth hormone: six years of experience.

PubMed

Ramaswami, U; Rumsby, G; Spoudeas, H A; Hindmarsh, P C; Brook, C G

1999-10-01

We describe the effects of recombinant hGH (r-hGH) therapy for up to 6 y on stature and body proportions of 35 children with achondroplasia (Ach). Consecutive height (Ht) measurements were plotted on disease-specific Ach growth curves, but age and sex SD scores (SDS) of Ht, sitting Ht, subischial leg length, and Ht velocity were made with respect to Tanner normal standards. r-hGH was administered by daily subcutaneous injections at a median (range) dose of 30 (15.8-40) U/m2 per week [0.06 (0.04-0.08) mg.kg(-1).24 h(-1)]. Patients were treated for 3 (1-6) y from age 2.25 (1.2-9.3) y. Before treatment, Ht SDS was -4.6 (-6.5 to -3.24). Treatment caused a significant increase in Ht SDS year to year until y 4 (ANOVA F = 46.94; p < 0.01) that was subsequently sustained with no significant further change (y 5 and 6 versus y 4, p > 0.05). When the response to r-hGH was also expressed as a change in Ht velocity, there was a significant increase in the first year of therapy that was maintained over subsequent treatment years (ANOVA = 4.28, p = 0.001). Age was the most important variable accounting for the first-year response in Ht SDS (r2 = 0.41, p < 0.001), and dose of r-hGH did not influence this. Increments in sitting Ht SDS were greater than subischial leg length SDS (F = 26.25, p < 0.001; F = 9.04, p < 0.001, respectively). r-hGH treatment improved the Ht position of Ach children relative to their normal and Ach peers without obvious side effects. A young age at initiation of therapy prevented the characteristic Ht deficit from accumulating. The greater increase in spinal Ht accentuated the existing disproportion. The addition of later surgical leg lengthening could offer the possibility of proportionate adult stature just within the normal range.

Vascular anatomy of the medial sural artery perforator flap: a new classification system of intra-muscular branching patterns.

PubMed

Dusseldorp, Joseph R; Pham, Quy J; Ngo, Quan; Gianoutsos, Mark; Moradi, Pouria

2014-09-01

The medial sural artery perforator (MSAP) flap is a versatile fasciocutaneous flap. The main difficulty encountered when raising the MSAP flap is in obtaining adequate pedicle length during intra-muscular dissection. The objective of this study was to determine the pattern of intra-muscular course of the MSAP flap pedicle. 14 cadaveric specimens were dissected and CT angiograms of 84 legs were examined. The intra-muscular branching pattern and depths of the medial sural artery branches were analyzed. The number of perforators, position of the dominant perforator and both intra-muscular and total pedicle length were also recorded and compared to existing anatomical data. Three types of arterial branching pattern were identified within the medial gastrocnemius, demonstrating one (31%), two (59%) or three or more (10%) main branches. A dominant perforator from the medial sural artery was present in 92% of anatomical specimens (13/14). Vertically, the location of the perforator from the popliteal crease was on average 13 cm (±2 cm). Transversely, the perforator originated 2.5 cm (±1 cm) from the posterior midline. Using CT angiography it was possible in 10 consecutive patients to identify a more superficial intra-muscular branch and determine the leg with the optimal branching pattern type for flap harvest. This study is the first to describe the variability of the intra-muscular arterial anatomy of the medial head of gastrocnemius muscle. Surgeons utilizing the MSAP flap option should be aware of the possible branching pattern types and consequently the differing perforator distribution and depths of intra-muscular branches. Routine use of pre-operative CT angiogram may help determine which leg has the most favorable branching pattern type and intra-muscular course for flap harvest. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Mechanical Alterations during 800-m Self-Paced Track Running.

PubMed

Girard, Olivier; Millet, Gregoire P; Micallef, Jean-Paul

2017-04-01

We assessed the time course of running mechanical alterations during an 800-m. On a 200-m indoor track, 18 physical education students performed an 800-m self-paced run. Once per lap, ground reaction forces were measured by a 5-m-long force platform system, and used to determine running kinetics/kinematics and spring-mass characteristics. Compared with 100 m (19.4±1.8 km.h -1 ) running velocity progressively decreased at 300, 500 m but levelled-off at 700 m marks (-5.7±4.6, -10.4±8.3, and -9.1±13.5%, respectively; P<0.001). Stride length (-8.5±2.3%, P<0.01) and frequency (-1.0±1.5%, P=0.05) along with peak braking (-7.5±4.4%, P<0.05) and push-off forces (-5.1±7.2%, P<0.05) decreased from 100 m to 700 m. Peak vertical forces (-3.0±2.7%; P>0.05) and leg compression (+2.8±3.9%; P>0.05) remained unchanged, whereas centre of mass vertical displacement (+24.0±7.0%; P<0.001) increased during the run. Vertical stiffness decreased (-18.1±4.4%; P<0.001), whereas leg stiffness was unchanged (-3.2±4.6%; P>0.05). During an 800 m by physical education students, highest running velocity was achieved early during the run, with a progressive decrease in the second half of the trial. While vertical ground force characteristics remained unchanged, non-specialist runners produced lower peak braking and push-off forces, in turn leading to shorter stride length. Spring-mass model characteristics changed toward lower vertical stiffness values, whereas leg stiffness did not change. © Georg Thieme Verlag KG Stuttgart · New York.

Enchondromatosis with features of dysspondyloenchondromatosis and Maffucci syndrome.

PubMed

Haga, N; Nakamura, K; Taniguchi, K; Nakamura, S

1998-01-01

We report a girl with multiple enchondromatosis, unequal leg length, short stature, congenital scoliosis, lymphangioma, and cutaneous hemangiomata. The skeletal findings were consistent with the clinical and radiological features of dysspondyloenchondromatosis except that short stature was not apparent in the neonatal period. Dysspondyloenchondromatosis is a rare disorder, one of the several types of multiple enchondromatosis with spinal abnormalities. In previous reports of this condition the association of vascular lesions usually found in Maffucci syndrome has not been described.

Stabilization of a three-dimensional limit cycle walking model through step-to-step ankle control.

PubMed

Kim, Myunghee; Collins, Steven H

2013-06-01

Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss of active ankle control. If ankle control can contribute significantly to maintaining balance, even in the presence of active foot placement, this might provide an opportunity to improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods in a three-dimensional model of human gait that included ankle plantarflexion, ankle inversion-eversion, hip flexion-extension, and hip ad/abduction. We generated discrete feedback control laws (linear quadratic regulators) that altered nominal actuation parameters once per step. We used ankle push-off, lateral ankle stiffness and damping, fore-aft foot placement, lateral foot placement, or all of these as control inputs. We modeled environmental disturbances as random, bounded, unexpected changes in floor height, and defined balance performance as the maximum allowable disturbance value for which the model walked 500 steps without falling. Nominal walking motions were unstable, but were stabilized by all of the step-to-step control laws we tested. Surprisingly, step-by-step modulation of ankle push-off alone led to better balance performance (3.2% leg length) than lateral foot placement (1.2% leg length) for these control laws. These results suggest that appropriate control of robotic ankle-foot prosthesis push-off could make balancing during walking easier for individuals with amputation.

[Experiences with the condition of resection of the hip joint following removal of the alloarthroplastic implantate (author's transl)].

PubMed

Reflor, H J; Wirth, C J; Schreiner, B

1979-10-01

30 patients whose total endoprosthesis of the hip joint had been removed without any replacement, thus creating a so-called state of secondary resection, were followed up 6 months to 6 years after the operation. It was found that in almost two-thirds of the cases a subjective feeling of improved mobility was reported. The objective findings consisted in restrictions of the total rotation, abduction and adduction of 1/3 rd of the normal extent of mobility. An average value of 74.7 degrees was recorded for flexion. 28 patients stated that their walking performance was satisfactory to very good when using a walking-stick as support. More than three-quarters of the patients questioned stated their pain had been positively influenced by the creation of the state of secondary resection. Another objective finding was a difference between the length of the legs amounting to 4.2 cm on the average. We could prove the existence of a relationship between the difference in leg length and the roentgenologically visualised supporting of the resection area of the coxal end of the femur at the lateral pelvis. Since all the patients with the exception of two could resume their customary daily routine activities, the state of secondary resection after unsuccessful total endoprosthesis of the hip joint must be considered a reasonably acceptable alternative.

Reliable Thermoelectric Module Design under Opposing Requirements from Structural and Thermoelectric Considerations

NASA Astrophysics Data System (ADS)

Karri, Naveen K.; Mo, Changki

2018-06-01

Structural reliability of thermoelectric generation (TEG) systems still remains an issue, especially for applications such as large-scale industrial or automobile exhaust heat recovery, in which TEG systems are subject to dynamic loads and thermal cycling. Traditional thermoelectric (TE) system design and optimization techniques, focused on performance alone, could result in designs that may fail during operation as the geometric requirements for optimal performance (especially the power) are often in conflict with the requirements for mechanical reliability. This study focused on reducing the thermomechanical stresses in a TEG system without compromising the optimized system performance. Finite element simulations were carried out to study the effect of TE element (leg) geometry such as leg length and cross-sectional shape under constrained material volume requirements. Results indicated that the element length has a major influence on the element stresses whereas regular cross-sectional shapes have minor influence. The impact of TE element stresses on the mechanical reliability is evaluated using brittle material failure theory based on Weibull analysis. An alternate couple configuration that relies on the industry practice of redundant element design is investigated. Results showed that the alternate configuration considerably reduced the TE element and metallization stresses, thereby enhancing the structural reliability, with little trade-off in the optimized performance. The proposed alternate configuration could serve as a potential design modification for improving the reliability of systems optimized for thermoelectric performance.

Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft.

PubMed

Chou, Ying-Chao; Lee, Demei; Chang, Tzu-Min; Hsu, Yung-Heng; Yu, Yi-Hsun; Liu, Shih-Jung; Ueng, Steve Wen-Neng

2016-04-20

This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft

PubMed Central

Chou, Ying-Chao; Lee, Demei; Chang, Tzu-Min; Hsu, Yung-Heng; Yu, Yi-Hsun; Liu, Shih-Jung; Ueng, Steve Wen-Neng

2016-01-01

This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft. PMID:27104525

Associations between orthopaedic disturbances and unilateral crossbite in children with asymmetry of the upper cervical spine.

PubMed

Korbmacher, Heike; Koch, L; Eggers-Stroeder, G; Kahl-Nieke, B

2007-02-01

The objective of the present study was to detect possible associations between unilateral crossbite and orthopaedic disturbances in children with asymmetry of the upper cervical spine. Fifty-five children aged 3-10 years (22 girls and 33 boys) with a unilateral crossbite and 55 gender- and age-matched children with a symmetric occlusion but no crossbite, who served as the control group, were selected from an orthopaedic cohort of 240 patients. In all children, asymmetry of the upper cervical region was confirmed by radiographs and palpation. The following orthopaedic aspects were investigated: oblique shoulder and pelvis, scoliosis, functional leg length difference, and laxity of ligaments of the foot. The differences between the groups were analysed by means of an unpaired t-test. An increased occurrence of orthopaedic parameters in the frontal plane was observed in children with a unilateral malocclusion. A unilateral crossbite was not necessarily combined with a pathological orthopaedic variable, but statistically, children with a unilateral malocclusion showed more often an oblique shoulder (P = 0.004), scoliosis (P = 0.04), an oblique pelvis (P = 0.007), and a functional leg length difference (P = 0.002) than children with symmetry. The results suggest that a unilateral crossbite in children with asymmetry of the upper cervical spine is associated with orthopaedic disturbances. There is no evidence of a causal link.

What happens with cow behavior when replacing concrete slatted floor by rubber coating: a case study.

PubMed

Platz, S; Ahrens, F; Bendel, J; Meyer, H H D; Erhard, M H

2008-03-01

An enhanced productive life cycle and improved animal welfare are aims pursued in dairy husbandry. This study assesses experimental observations on floor-associated behavior during the stepwise replacement of concrete slatted flooring by rubber mats. For this purpose, estrus (mounting) and hygiene behavior (licking while standing on 3 legs and caudal licking) within a herd of 50 loose-housed Brown Swiss dairy cows were analyzed by video observation before and after floor reconstruction. Still photographs and pedometers were used to asses step length and number of steps, representing walking behavior. Compared with the concrete floor surface, rubber coating led to an increase in step length (58 +/- 1 vs. 70 +/- 1 cm; n = 35) and in steps per day (4,226 +/- 450 vs. 5,611 +/- 495; mean +/- SEM; n = 9). Mounting was higher on the flooring covered with rubber mats (23 vs. 112). Collapsing or slipping during mounting only occurred on concrete slatted flooring (in 19 out of 23 mounting actions). Licking while standing on 3 legs and caudal licking increased up to 4-fold (105 vs. 511 observations). In conclusion, improvements were found in behavior when rubber-coated slatted floor surfaces were used in dairy cattle housing in transition from concrete flooring. Disorders in estrus and hygiene behavior were associated with the flooring of the barn and were relatively easy to investigate within the framework of farm welfare assessments.

The effects of the arm swing on biomechanical and physiological aspects of roller ski skating.

PubMed

Hegge, Ann Magdalen; Ettema, Gertjan; de Koning, Jos J; Rognstad, Asgeir Bakken; Hoset, Martin; Sandbakk, Øyvind

2014-08-01

This study analyzed the biomechanical and physiological effects of the arm swing in roller ski skating, and compared leg-skating (i.e. ski skating without poles) using a pronounced arm swing (SWING) with leg-skating using locked arms (LOCKED). Sixteen elite male cross-country skiers performed submaximal stages at 10, 15 and 20kmh(-1) on a 2% inclined treadmill in the two techniques. SWING demonstrated higher peak push-off forces and a higher force impulse at all speeds, but a longer cycle length only at the highest speed (all P<.05), indicating a lower force effectiveness with SWING at the two lowest speeds. Additionally, the flexion-extension movement in the lower limbs was more pronounced for SWING. Oxygen uptake was higher for SWING at the two lowest speeds (both P<.05) without any differences in blood lactate. At the highest speed, oxygen uptake did not differ between SWING and LOCKED, but the RER, blood lactate and ventilation were lower with SWING (all P<.05). Taken together, these results demonstrate that utilizing the arm swing in roller ski skating increases the ski forces and aerobic energy cost at low and moderate speeds, whereas the greater forces at high speed lead to a longer cycle length and smaller anaerobic contribution. Copyright © 2014 Elsevier B.V. All rights reserved.

Tendon Contraction After Cyclic Elongation Is an Age-Dependent Phenomenon: In Vitro and In Vivo Comparisons.

PubMed

Lavagnino, Michael; Bedi, Asheesh; Walsh, Christopher P; Sibilsky Enselman, Elizabeth R; Sheibani-Rad, Shahin; Arnoczky, Steven P

2014-06-01

Tendons are viscoelastic tissues that deform (elongate) in response to cyclic loading. However, the ability of a tendon to recover this elongation is unknown. Tendon length significantly increases after in vivo or in vitro cyclic loading, and the ability to return to its original length through a cell-mediated contraction mechanism is an age-dependent phenomenon. Controlled laboratory study. In vitro, rat tail tendon fascicles (RTTfs) from Sprague-Dawley rats of 3 age groups (1, 3, and 12 months) underwent 2% cyclic strain at 0.17 Hz for 2 hours, and the percentages of elongation were determined. After loading, the RTTfs were suspended for 3 days under tissue culture conditions and photographed daily to determine the amount of length contraction. In vivo, healthy male participants (n = 29; age, 19-49 years) had lateral, single-legged weightbearing radiographs taken of the knee at 60° of flexion immediately before, immediately after, and 24 hours after completing eccentric quadriceps loading exercises on the dominant leg to fatigue. Measurements of patellar tendon length were taken from the radiographs, and the percentages of tendon elongation and subsequent contraction were calculated. In vitro, cyclic loading increased the length of all RTTfs, with specimens from younger (1 and 3 months) rats demonstrating significantly greater elongation than those from older (12 months) rats (P = .009). The RTTfs contracted to their original length significantly faster (P < .001) and in an age-dependent fashion, with younger animals contracting faster. In vivo, repetitive eccentric loading exercises significantly increased patellar tendon length (P < .001). Patellar tendon length decreased 24 hours after exercises (P < .001) but did not recover completely (P < .001). There was a weak but significant (R (2) = 0.203, P = .014) linear correlation between the amount of tendon contraction and age, with younger participants (<30 years) demonstrating significantly more contraction (P = .014) at 24 hours than older participants (>30 years). Cyclic tendon loading results in a significant increase in tendon elongation under both in vitro and in vivo conditions. Tendons in both conditions demonstrated an incomplete return to their original length after 24 hours, and the extent of this return was age dependent. The age- and time-dependent contraction of tendons, elongated after repetitive loading, could result in transient alterations in the mechanobiological environment of tendon cells. This, in turn, could induce the onset of catabolic changes associated with the pathogenesis of tendinopathy. These results suggest the importance of allowing time for contraction between bouts of repetitive exercise and may explain why age is a predisposing factor in tendinopathy. © 2014 The Author(s).