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1

Comparison of neuromuscular and quadriceps strengthening exercise in the treatment of varus malaligned knees with medial knee osteoarthritis: a randomised controlled trial protocol  

PubMed Central

Background Osteoarthritis of the knee involving predominantly the medial tibiofemoral compartment is common in older people, giving rise to pain and loss of function. Many people experience progressive worsening of the disease over time, particularly those with varus malalignment and increased medial knee joint load. Therefore, interventions that can reduce excessive medial knee loading may be beneficial in reducing the risk of structural progression. Traditional quadriceps strengthening can improve pain and function in people with knee osteoarthritis but does not appear to reduce medial knee load. A neuromuscular exercise program, emphasising optimal alignment of the trunk and lower limb joints relative to one another, as well as quality of movement performance, while dynamically and functionally strengthening the lower limb muscles, may be able to reduce medial knee load. Such a program may also be superior to traditional quadriceps strengthening with respect to improved pain and physical function because of the functional and dynamic nature. This randomised controlled trial will investigate the effect of a neuromuscular exercise program on medial knee joint loading, pain and function in individuals with medial knee joint osteoarthritis. We hypothesise that the neuromuscular program will reduce medial knee load as well as pain and functional limitations to a greater extent than a traditional quadriceps strengthening program. Methods/Design 100 people with medial knee pain, radiographic medial compartment osteoarthritis and varus malalignment will be recruited and randomly allocated to one of two 12-week exercise programs: quadriceps strengthening or neuromuscular exercise. Each program will involve 14 supervised exercise sessions with a physiotherapist plus four unsupervised sessions per week at home. The primary outcomes are medial knee load during walking (the peak external knee adduction moment from 3D gait analysis), pain, and self-reported physical function measured at baseline and immediately following the program. Secondary outcomes include the external knee adduction moment angular impulse, electromyographic muscle activation patterns, knee and hip muscle strength, balance, functional ability, and quality-of-life. Discussion The findings will help determine whether neuromuscular exercise is superior to traditional quadriceps strengthening regarding effects on knee load, pain and physical function in people with medial knee osteoarthritis and varus malalignment. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12610000660088

2011-01-01

2

Quadriceps oxygenation during isometric exercise in sailing.  

PubMed

The aim of the present study was to investigate why blood lactate after prolonged quadriceps contraction during hiking is only marginally increased. Eight sailors performed five 3-min hiking bouts interspersed with 5-s recovery periods. Whole body oxygen uptake, heart rate and lactate were recorded, along with continuous-wave near-infrared spectroscopy measures of quadriceps oxygenation. The time for 50% re-oxygenation was also assessed as an indication of the degree of localized oxygen delivery stress. Hiking elicited a significant (p = 0.001) increase in mean (+/- SD) heart rate (124 +/- 10 beats . min (-1)) which was accompanied by a disproportionately low oxygen uptake (12 +/- 2 ml.kg(-1).min(-1)). Lactate was significantly (p = 0.001) increased throughout hiking manoeuvres, though post-exercise it remained low (3.2 +/- 0.9 mmol.l(-1)). During the hiking bouts mean quadriceps oxygenation was significantly (p = 0.001) reduced compared to baseline (by 33 +/- 5%), indicating an imbalance between muscle oxygen accessibility and oxygen demand. During rest intervals quadriceps oxygenation was partially restored. After the end of the final bout the time for 50 % re-oxygenation was only 8 +/- 2 s, whereas recovery of quadriceps oxygenation and oxygen uptake was completed within 3 min. We conclude that the observed low lactate could be attributed to the small oxygen and energy deficits during hiking as the muscles' oxygen accessibility is presumably partially restored during the brief rest intervals. PMID:17614020

Vogiatzis, I; Tzineris, D; Athanasopoulos, D; Georgiadou, O; Geladas, N

2007-07-05

3

The Effect of Baseline Quadriceps Activation on Changes in Quadriceps Strength After Exercise Therapy in Subjects with Knee Osteoarthritis  

PubMed Central

Objective The aim of this study was to examine whether pretreatment magnitude of quadriceps activation (QA) helps predict changes in quadriceps strength after exercise therapy in subjects with knee osteoarthritis (OA). We hypothesized that subjects with lower magnitudes of QA (greater failure of muscle activation) would have smaller gains in strength compared to those with higher magnitudes of QA following exercise therapy. Methods 111 subjects with knee OA (70 ?) participated in the study. Baseline measures included demographic information, quadriceps muscle strength and QA using a burst-superimposition isometric torque test. Following baseline testing, subjects underwent a 6 week supervised exercise program designed to improve strength, range of motion, balance and agility, and physical function. On completion of the exercise program, quadriceps strength and QA were re-assessed. Multiple regression analysis was used to determine whether baseline QA predicted quadriceps strength scores at the 2 month follow-up period. Results Bivariate correlations demonstrated that baseline QA was significantly associated with quadriceps strength at baseline (rho = 0.30, p < 0.01) and 2 month follow-up (rho = 0.23, p = 0.01). Greater magnitude of baseline QA correlated to higher strength. While controlling for baseline quadriceps strength and type of exercise therapy, the level of QA did not predict quadriceps strength at the 2 month follow-up (? = ?0.04, p = 0.18). Conclusions Baseline QA did not predict changes in quadriceps strength following exercise therapy. Measurement of QA using the CAR method does not appear to be helpful in identifying subjects with knee OA who will have difficulty improving quadriceps strength with exercise therapy. Investigation of other factors that may affect response to exercise therapy is warranted.

Scopaz, Kristen A.; Piva, Sara R.; Gil, Alexandra B.; Woollard, Jason D.; Oddis, Chester V.; Fitzgerald, G. Kelley

2009-01-01

4

Disability in patients with chronic patellofemoral pain syndrome: a randomised controlled trial of VMO selective training versus general quadriceps strengthening.  

PubMed

This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69) were recruited from a hospital orthopaedic clinic and randomised into three groups: (1) physiotherapy with emphasis on selectively retraining the VMO (Selective); (2) physiotherapy with emphasis on general strengthening of the quadriceps femoris muscles (General); and (3) a no-treatment control group (Control). The three groups were then compared before and after an eight-week rehabilitation period. The Selective and General groups demonstrated statistically significant and 'moderate' to 'large' effect size reductions in pain when compared to the Control group. Both the Selective and General groups displayed statistically significant and 'moderate' and 'large' effect size improvements in subjective function and Quality of Life compared to the Control group. Knee flexion excursion during the stance phase of gait, demonstrated that there were no statistical significant differences and only 'trivial' to 'small' effect size differences between the Selective or General groups and the Control group. A large number of PFPS patients can experience significant improvements in pain, function and Quality of Life, at least in the short term, with quadriceps femoris rehabilitation, with or without emphasis on selective activation of the VMO component. Both approaches would seem acceptable for rehabilitating patients with PFPS. It may be appropriate to undertake exercises involving selective activation of the vastus medialis early in the rehabilitation process, however, clinicians should not overly focus on selective activation before progressing rehabilitation, especially in more chronic cases with significant participation restrictions. PMID:18436468

Syme, G; Rowe, P; Martin, D; Daly, G

2008-04-24

5

Disability in patients with chronic patellofemoral pain syndrome: A randomised controlled trial of VMO selective training versus general quadriceps strengthening  

Microsoft Academic Search

This study was a prospective single blind randomised controlled trial to compare the effects of rehabilitation with emphasis on retraining the vastus medialis (VMO) component of the quadriceps femoris muscle and rehabilitation with emphasis on general strengthening of the quadriceps femoris muscles on pain, function and Quality of Life in patients with patellofemoral pain syndrome (PFPS). Patients with PFPS (n=69)

G. Syme; P. Rowe; D. Martin; G. Daly

2009-01-01

6

Closed kinetic chain alone compared to combined open and closed kinetic chain exercises for quadriceps strengthening after anterior cruciate ligament reconstruction with respect to return to sports: a prospective matched follow-up study  

Microsoft Academic Search

Rehabilitation after anterior cruciate ligament (ACL) reconstruction has focused over the past decade on closed kinetic chain (CKC) exercises due to presumably less strain on the graft than with isokinetic open kinetic chain exercises (OKC); however, recent reports suggest that there are only minor differences in ACL strain values between some CKC and OKC exercises. We studied anterior knee laxity,

C. Mikkelsen; S. Werner; E. Eriksson

2000-01-01

7

Effects of Massage on Limb and Skin Blood Flow after Quadriceps Exercise  

Microsoft Academic Search

HINDS, T., I. MCEWAN, J. PERKES, E. DAWSON, D. BALL, and K. GEORGE. Effects of Massage on Limb and Skin Blood Flow after Quadriceps Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 8, pp. 1308-1313, 2004. Purpose: At present, thereis little scientific evidence that postexercise manual massage has any effect on the factors associated with the recovery process. The purpose

TESSA HINDS; ISLAY MCEWAN; JILL PERKES; ELLEN DAWSON; DEREK BALL; KEITH GEORGE

2004-01-01

8

Acute effects of dietary ginger on quadriceps muscle pain during moderate-intensity cycling exercise.  

PubMed

Ginger has known hypoalgesic and anti-inflammatory properties. The effects of an oral dose of ginger on quadriceps muscle pain, rating of perceived exertion (RPE), and recovery of oxygen consumption were examined during and after moderate-intensity cycling exercise. Twenty-five college-age participants ingested a 2-g dose of ginger or placebo in a double-blind, crossover design and 30 min later completed 30 min of cycling at 60% of VO2peak. Quadriceps muscle pain, RPE, work rate, heart rate (HR), and oxygen uptake (VO2) were recorded every 5 min during exercise, and HR and VO2 were recorded for 20 min after exercise. Compared with placebo, ginger had no clinically meaningful or statistically significant effect on perceptions of muscle pain, RPE, work rate, HR, or VO2 during exercise. Recovery of VO2 and HR after the 30-min exercise bout followed a similar time course in the ginger and placebo conditions. The results were consistent with related findings showing that ingesting a large dose of aspirin does not acutely alter quadriceps muscle pain during cycling, and this suggests that prostaglandins do not play a large role in this type of exercise-induced skeletal-muscle pain. Ginger consumption has also been shown to improve VO2 recovery in an equine exercise model, but these results show that this is not the case in humans. PMID:19164834

Black, Christopher D; Oconnor, Patrick J

2008-12-01

9

Quadriceps and Diaphragmatic Function after Exhaustive Cycle Exercise in the Healthy Elderly  

Microsoft Academic Search

The purpose of this study was to determine whether quadriceps or diaphragmatic fatigue or both occur after high-intensity cycle ex- ercise to exhaustion in healthy elderly persons. Ten relatively sed- entary male subjects aged 68.3 6 1.4 yr (mean 6 SE) (range: 60 to 75 yr) exercised at 65% to 75% of their predetermined maximal work capacity to the limits

M. JEFFERY MADOR; THOMAS J. KUFEL; LILIBETH A. PINEDA

2000-01-01

10

Differential Glucose Uptake in Quadriceps and Other Leg Muscles During One-Legged Dynamic Submaximal Knee-Extension Exercise  

PubMed Central

One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron emission tomography (PET) determined uptake of [18F]-fluoro-deoxy-glucose (GU) during DKE. Five healthy male subjects performed DKE at 25?W for 35?min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest in the vastus intermedius (VI) and lowest in the vastus lateralis (VL; VI vs VL, p?quadriceps femoris (QF) muscles in the exercising leg was 35?±?9%. Compared to mean GU in QF (=100%), GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between individuals vary greatly during DKE, and suggests that muscle activity is not equal between quadriceps muscles in this exercise model. Furthermore, posterior thigh muscles and lower leg muscles are more active than hitherto thought even during this moderate exercise intensity.

Kalliokoski, Kari K.; Boushel, Robert; Langberg, Henning; Scheede-Bergdahl, Celena; Ryberg, Ann Kathrine; D?ssing, Simon; Kjaer, Andreas; Kjaer, Michael

2011-01-01

11

Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise.  

PubMed

One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron emission tomography (PET) determined uptake of [(18)F]-fluoro-deoxy-glucose (GU) during DKE. Five healthy male subjects performed DKE at 25?W for 35?min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest in the vastus intermedius (VI) and lowest in the vastus lateralis (VL; VI vs VL, p?quadriceps femoris (QF) muscles in the exercising leg was 35?±?9%. Compared to mean GU in QF (=100%), GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between individuals vary greatly during DKE, and suggests that muscle activity is not equal between quadriceps muscles in this exercise model. Furthermore, posterior thigh muscles and lower leg muscles are more active than hitherto thought even during this moderate exercise intensity. PMID:22046164

Kalliokoski, Kari K; Boushel, Robert; Langberg, Henning; Scheede-Bergdahl, Celena; Ryberg, Ann Kathrine; Døssing, Simon; Kjær, Andreas; Kjær, Michael

2011-10-25

12

Relative Activity of Abdominal Muscles during Commonly Prescribed Strengthening Exercises.  

ERIC Educational Resources Information Center

|Examined the relative electromyographic (EMG) activity of upper and lower rectus abdominis (LRA) and external oblique (EOA) muscles during five abdominal strengthening exercises. Isometric and dynamic EMG data indicated that abdominal strengthening exercises activated various abdominal muscle groups. For the LRA and EOA muscle groups, there were…

Willett, Gilbert M.; Hyde, Jennifer E.; Uhrlaub, Michael B.; Wendel, Cara L.; Karst, Gregory M.

2001-01-01

13

The effect of sports specialization on musculus quadriceps function after exercise-induced muscle damage.  

PubMed

The primary aim of the present study was to examine the effect of eccentric exercise-induced (100 submaximal eccentric contractions at an angular velocity of 60° s?¹, with 20-s rest intervals) muscle damage on peripheral and central fatigue of quadriceps muscle in well-trained long-distance runners, sprint runners, volleyball players, and untrained subjects. We found that (i) indirect symptoms of exercise-induced muscle damage (prolonged decrease in maximal voluntary contraction, isokinetic concentric torque, and electrically induced (20 Hz) torque) were most evident in untrained subjects, while there were no significant differences in changes of muscle soreness and plasma creatine kinase 48 h after eccentric exercise between athletes and untrained subjects; (ii) low-frequency fatigue was greater in untrained subjects and volleyball players than in sprint runners and long-distance runners; (iii) in all subjects, electrically induced (100 Hz) torque decreased significantly by about 20%, while central activation ratio decreased significantly by about 8% in untrained subjects and sprint runners, and by about 3%-5% in long-distance runners and volleyball players. Thus, trained subjects showed greater resistance to exercise-induced muscle damage for most markers, and long-distance runners had no advantage over sprint runners or volleyball players. PMID:22050132

Skurvydas, Albertas; Brazaitis, Marius; Venck?nas, Tomas; Kamandulis, Sigitas; Stanislovaitis, Aleksas; Zuoza, Aurelijus

2011-11-03

14

Recruitment of fibre types and quadriceps muscle portions during repeated, intense knee-extensor exercise in humans  

Microsoft Academic Search

To investigate recruitment of slow-twitch (ST) and fast-twitch (FT) muscle fibres, as well as the involvement of the various quadriceps femoris muscle portions during repeated, intense, one-legged knee-extensor exercise, 12 healthy male subjects performed two 3-min exercise bouts at ~110% maximum thigh O 2 consumption (EX1 and EX2) separated by 6 min rest. Single-fibre metabolites were determined in successive muscle biopsies

Peter Krustrup; Karin Söderlund; Magni Mohr; José González-Alonso; Jens Bangsbo

2004-01-01

15

Strengthening the pelvic floor with Kegel exercises  

Microsoft Academic Search

Pelvic floor exercises (PFE) have become a standard nursing intervention, both to prevent as well as to treat incontinence. A review of the literature shows great variety in the protocols for performing PFE, and inconsistent use of perineometers, palpation tests, or other biofeedback devices. Results are difficult to compare because of methodological inconsistencies. Suggestions for further research are included.

C. A. Pierson

1990-01-01

16

Effect of caffeine on quadriceps muscle pain during acute cycling exercise in low versus high caffeine consumers.  

PubMed

This experiment examined the effect of a moderate dose of caffeine on quadriceps muscle pain during a bout of high-intensity cycling in low- versus high-caffeine-consuming males. College-age men who were low (< or =100 mg/day; n = 12) or high (> or =400 mg/day; n = 13) habitual caffeine consumers ingested caffeine (5 mg/kg body weight) or a placebo in a counterbalanced order and 1 hr later completed 30 min of cycle ergometry at 75-77% of peak oxygen consumption. Perceptions of quadriceps muscle pain, as well as oxygen consumption, heart rate, and work rate, were recorded during both bouts of exercise. Caffeine ingestion resulted in a statistically significant and moderate reduction in quadriceps muscle-pain-intensity ratings during the 30-min bout of high-intensity cycle ergometry compared with placebo ingestion in both low (d = -0.42) and high (d = -0.55) caffeine consumers. The results suggest that caffeine ingestion is associated with a moderate hypoalgesic effect during high-intensity cycling in college-age men who are low or high habitual caffeine consumers, but future work should consider better defining and differentiating pain and effort when examining the effects of caffeine during acute exercise. PMID:19478340

Gliottoni, Rachael C; Meyers, John R; Arngrimsson, Sigurbjorn A; Broglio, Steven P; Motl, Robert W

2009-04-01

17

Effect of whole-body vibration exercise and muscle strengthening, balance, and walking exercises on walking ability in the elderly  

Microsoft Academic Search

The present study was conducted to determine the beneficial effect of whole- body vibration (WBV) exercise in addition to muscle strengthening, balance, and walking exercises on the walking ability in the elderly. Sixty-seven elderly participants were divided into two groups; the WBV exercise plus routine exercises group (n=40) and the routine ex- ercises alone group (n=27). WBV exercise was performed

Kazuhiro Kawanabe; Akira Kawashima; Issei Sashimoto; Tsuyoshi Takeda; Yoshihiro Sato; Jun Iwamoto

2007-01-01

18

Effect of cross exercise on quadriceps acceleration reaction time and subjective scores (Lysholm questionnaire) following anterior cruciate ligament reconstruction  

PubMed Central

Background Anterior cruciate ligament (ACL) injury or reconstruction can cause knee impairments and disability. Knee impairments are related to quadriceps performance – accelerated reaction time (ART) – and disability to performance of daily living activities which is assessed by questionnaires such as the Lysholm knee score. The purposes of this study were to investigate the effect of cross exercise, as supplementary rehabilitation to the early phase of ACL reconstruction: a) on quadriceps ART at the angles 45°, 60° and 90° of knee flexion and, b) on the subjective scores of disability in ACL reconstructed patients. Methods 42 patients who underwent ACL reconstruction were randomly divided into 3 groups, two experimental and one control. All groups followed the same rehabilitation program. The experimental groups followed 8 weeks of cross eccentric exercise (CEE) on the uninjured knee; 3 d/w, and 5 d/w respectively. Quadriceps ART was measured at 45°, 60° and 90° of knee flexion pre and nine weeks post-operatively using an isokinetic dynamometer. Patients also completed pre and post operatively the Lysholm questionnaire whereby subjective scores were recorded. Results Two factor ANOVA showed significant differences in ART at 90° among the groups (F = 4.29, p = 0.02, p < 0.05). Post hoc Tukey HSD analysis determined that the significant results arose from the first experimental group in comparison to the control (D = -0.83, p = 0.01). No significant differences were revealed at 45° and 60°. Significant differences were also found in the Lysholm score among the groups (F = 4.75, p = 0.01, p < 0.05). Post hoc analysis determined that the above significant results arose from the first experimental group in comparison with the control (D = 7.5, p < 0.01) and from the second experimental in comparison with the control (D = 3.78, p = 0.03). Conclusion CEE showed improvements on quadriceps ART at 90° at a sequence of 3 d/w and in the Lysholm score at a sequence of 3 d/w and 5 d/w respectively on ACL reconstructed patients.

Papandreou, Maria G; Billis, Evdokia V; Antonogiannakis, Emmanouel M; Papaioannou, Nikos A

2009-01-01

19

The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise  

PubMed Central

The relationship between muscle deoxygenation and activation was examined in three different muscles of the quadriceps during cycling ramp exercise. Seven young male adults (24 ± 3 yr; mean ± SD) pedaled at 60 rpm to exhaustion, with a work rate (WR) increase of 20 W/min. Pulmonary oxygen uptake was measured breath-by-breath, while muscle deoxygenation (HHb) and activity were measured by time-resolved near-infrared spectroscopy (NIRS) and surface electromyography (EMG), respectively, at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). Muscle deoxygenation was corrected for adipose tissue thickness and normalized to the amplitude of the HHb response, while EMG signals were integrated (iEMG) and normalized to the maximum iEMG determined from maximal voluntary contractions. Muscle deoxygenation and activation were then plotted as a percentage of maximal work rate (%WRmax). The HHb response for all three muscle groups was fitted by a sigmoid function, which was determined as the best fitting model. The c/d parameter for the sigmoid fit (representing the %WRmax at 50% of the total amplitude of the HHb response) was similar between VL (47 ± 12% WRmax) and VM (43 ± 11% WRmax), yet greater (P < 0.05) for RF (65 ± 13% WRmax), demonstrating a “right shift” of the HHb response compared with VL and VM. The iEMG also showed that muscle activation of the RF muscle was lower (P < 0.05) compared with VL and VM throughout the majority of the ramp exercise, which may explain the different HHb response in RF. Therefore, these data suggest that the sigmoid function can be used to model the HHb response in different muscles of the quadriceps; however, simultaneous measures of muscle activation are also needed for the HHb response to be properly interpreted during cycle ramp exercise.

Chin, Lisa M. K.; Kowalchuk, John M.; Barstow, Thomas J.; Kondo, Narihiko; Amano, Tatsuro; Shiojiri, Tomoyuki

2011-01-01

20

Effects of vascular occlusion on maximal force, exercise-induced T2 changes, and EMG activities of quadriceps femoris muscles.  

PubMed

The purpose of our study was to determine the effect of vascular occlusion on neuromuscular activation and/or the energy metabolic characteristics of the quadriceps femoris (QF) muscles during muscle contractions. Seven men participated in the study. An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow in the anterior medial malleolar artery was reduced to approximately 88 % of the non-occluded flow. Muscle functional magnetic resonance imaging and maximal voluntary contraction (MVC) were carried out before and immediately after 5 sets of 10 repetitions of knee extension exercises at 50 % of the 10 repetitions maximum, from which transverse relaxation times (T2) and maximal force were measured, respectively. Integrated electromyography (iEMG) activity was recorded from the belly of the rectus femoris, vastus lateralis, and vastus medialis muscles during MVC and repetitive exercises. The percentage change in T2 was significantly increased for individual QF muscles, and there was a significant increase in iEMG activity over the 5 sets of repetitive exercises under conditions of vascular occlusion, but there was no significant effect on isometric force and iEMG activity during MVC. These results are consistent with the idea that there is greater osmolite accumulation during exercise with occlusion, although increased neural activation cannot be ruled out. PMID:16802245

Kinugasa, R; Watanabe, T; Ijima, H; Kobayashi, Y; Park, H G; Kuchiki, K; Horii, A

2006-07-01

21

Quadriceps Tendon Tear  

MedlinePLUS

... Specific exercises can restore strength and range of motion. Exercises will gradually be added to your program. ... move more freely with a greater range of motion. You will be prescribed more strengthening exercises as ...

22

Effect of L-Glutamine Supplementation on Electromyographic Activity of the Quadriceps Muscle Injured By Eccentric Exercise  

PubMed Central

Objective(s): The purpose of the present study was to examine the effects of L-glutamine on electromyographic (EMG) activity of the quadriceps muscle injured by eccentric exercise (EE). Materials and Methods: Seventeen healthy men (age: 22.35±2.27 yr; body mass: 69.91±9.78 kg; height: 177.08±4.32 cm) were randomly and double-blind study with subjects assigned to either an L-glutamine supplementation (n=9) or placebo (n=8) group. The subjects in two groups were asked to take three times during a week for 4 weeks. Each subject was screened for dietary habits before inclusion into the study. Participants performed 6 set to exhaustion eccentric leg extensions at 75% of 1RM and rest intervals were 3 min among sets. Pain Assessment Scale (PAS), EMG activity and range of motion (ROM) measurements were taken before exercise protocol and 24 and 48 hr afterwards. Results: There was no statistically significant difference between groups in perceived muscle soreness (SOR), ROM and EMG activity (P < 0.05). Conclusion: The results indicate that L-glutamine supplementation has no significant effect on muscle injury markers in between groups, although glutamine supplementation attenuated delayed onset muscle soreness (DOMS) effects in sup group.

Rahmani Nia, Farhad; Farzaneh, Esmail; Damirchi, Arsalan; Shamsi Majlan, Ali

2013-01-01

23

Effect of Lumbar Stabilization and Dynamic Lumbar Strengthening Exercises in Patients With Chronic Low Back Pain  

PubMed Central

Objective To compare the effects of lumbar stabilization exercises and lumbar dynamic strengthening exercises on the maximal isometric strength of the lumbar extensors, pain severity and functional disability in patients with chronic low back pain (LBP). Methods Patients suffering nonspecific LBP for more than 3 months were included prospectively and randomized into lumbar stabilization exercise group (n=11) or lumbar dynamic strengthening exercise group (n=10). Exercises were performed for 1 hour, twice weekly, for 8 weeks. The strength of the lumbar extensors was measured at various angles ranging from 0° to 72° at intervals of 12°, using a MedX. The visual analog scale (VAS) and the Oswestry Low Back Pain Disability Questionnaire (ODQ) were used to measure the severity of LBP and functional disability before and after the exercise. Results Compared with the baseline, lumbar extension strength at all angles improved significantly in both groups after 8 weeks. The improvements were significantly greater in the lumbar stabilization exercise group at 0° and 12° of lumbar flexion. VAS decreased significantly after treatment; however, the changes were not significantly different between the groups. ODQ scores improved significantly in the stabilization exercise group only. Conclusion Both lumbar stabilization and dynamic strengthening exercise strengthened the lumbar extensors and reduced LBP. However, the lumbar stabilization exercise was more effective in lumbar extensor strengthening and functional improvement in patients with nonspecific chronic LBP.

Moon, Hye Jin; Kim, Dae Ha; Kim, Ha Jeong; Cho, Young Ki; Lee, Kwang Hee; Kim, Jung Hoo; Choi, Yoo Jung

2013-01-01

24

Control of the rate of phosphocreatine resynthesis after exercise in trained and untrained human quadriceps muscles  

Microsoft Academic Search

We examined the effect of differences in exercise intensity on the time constant (t\\u000ac) of phosphocreatine (PCr) resynthesis after exercise and the relationships betweent\\u000ac and maximal oxygen uptake (VO2max) in endurance-trained runners (n = 5) and untrained controls (n = 7) (average VO2max = 66.2 and 52.0 ml · min–1 · kg–1, respectively). To measure the metabolism of

Hideyuki Takahashi; Mitsuharu Inaki; Koichi Fujimoto; Shigeru Katsuta; Izumi Anno; Mamoru Nütsu; Yuji Itai

1995-01-01

25

Quadriceps Fatigue after Cycle Exercise in Patients with Chronic Obstructive Pulmonary Disease  

Microsoft Academic Search

Patients with COPD have derangements in respiratory mechanics that may cause them to stop exer- cising before the exercising limb muscles reach their functional limits. However, because lung disease makes activity unpleasant, patients with chronic obstructive pulmonary disease (COPD) often adapt a sedentary lifestyle leading to progressive deconditioning. Deconditioning will lead to progressive de- terioration in limb muscle function, which

M. JEFFERY MADOR; THOMAS J. KUFEL; LILIBETH PINEDA

2000-01-01

26

Quadriceps Contusion  

MedlinePLUS

... it both tear. Quadriceps contusions are common in sports that involve a lot of direct contact, such ... and hockey. They're also a risk in sports where there's a chance of collisions, like soccer ...

27

Effects of exercise training on quadriceps muscle gene expression in chronic obstructive pulmonary disease.  

PubMed

Exercise capacity and training response are limited in chronic obstructive pulmonary disease (COPD), but the extent to which this is related to altered skeletal muscle function is not fully understood. To test the hypothesis that muscle gene expression is altered in COPD, we performed needle biopsies from the vastus lateralis of six COPD patients and five sedentary age-matched healthy men, before and after 3 mo of exercise training. RNA was hybridized to Affymetrix U133A Genechip arrays. In addition, peak O(2) uptake and other functional parameters (e.g., 6-min walk) were measured before and after training. The 6-min walk test increased significantly following training in both groups (53.6 +/- 18.6 m in controls, P = 0.045; 37.1 +/- 6.7 m in COPD, P = 0.002), but peak O(2) uptake increased only in controls (19.4 +/- 4.5%, P = 0.011). Training significantly altered muscle gene expression in both groups, but the number of affected genes was lower in the COPD patients (231) compared with controls (573). Genes related to energy pathways had higher expression in trained controls. In contrast, oxidative stress, ubiquitin proteasome, and COX gene pathways had higher expression in trained COPD patients, and some genes (e.g., COX11, COX15, and MAPK-9) were upregulated by training only in COPD patients. We conclude that both COPD and control subjects demonstrated functional responses to training but with somewhat different patterns in muscle gene expression. The pathways that are uniquely induced by exercise in COPD (e.g., ubiquitin proteasome and COX) might indicate a greater degree of tissue stress (perhaps by altered O(2) and CO(2) dynamics) than in controls. PMID:17483440

Radom-Aizik, Shlomit; Kaminski, Naftali; Hayek, Shlomo; Halkin, Hillel; Cooper, Dan M; Ben-Dov, Issahar

2007-05-01

28

MUSCLE ACTIVITY DURING KNEE-EXTENSION STRENGTHENING EXERCISE PERFORMED WITH ELASTIC TUBING AND ISOTONIC RESISTANCE  

PubMed Central

Background/Purpose: While elastic resistance training, targeting the upper body is effective for strength training, the effect of elastic resistance training on lower body muscle activity remains questionable. The purpose of this study was to evaluate the EMG?angle relationship of the quadriceps muscle during 10?RM knee?extensions performed with elastic tubing and an isotonic strength training machine. Methods: 7 women and 9 men aged 28?67 years (mean age 44 and 41 years, respectively) participated. Electromyographic (EMG) activity was recorded in 10 muscles during the concentric and eccentric contraction phase of a knee extension exercise performed with elastic tubing and in training machine and normalized to maximal voluntary isometric contraction (MVC) EMG (nEMG). Knee joint angle was measured during the exercises using electronic inclinometers (range of motion 0?90°). Results: When comparing the machine and elastic resistance exercises there were no significant differences in peak EMG of the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM) during the concentric contraction phase. However, during the eccentric phase, peak EMG was significantly higher (p<0.01) in RF and VM when performing knee extensions using the training machine. In VL and VM the EMG?angle pattern was different between the two training modalities (significant angle by exercise interaction). When using elastic resistance, the EMG?angle pattern peaked towards full knee extension (0°), whereas angle at peak EMG occurred closer to knee flexion position (90°) during the machine exercise. Perceived loading (Borg CR10) was similar during knee extensions performed with elastic tubing (5.7±0.6) compared with knee extensions performed in training machine (5.9±0.5). Conclusion: Knee extensions performed with elastic tubing induces similar high (>70% nEMG) quadriceps muscle activity during the concentric contraction phase, but slightly lower during the eccentric contraction phase, as knee extensions performed using an isotonic training machine. During the concentric contraction phase the two different conditions displayed reciprocal EMG?angle patterns during the range of motion. Level of Evidence: 5

Sundstrup, Emil; Andersen, Christoffer H.; Bandholm, Thomas; Thorborg, Kristian; Zebis, Mette K.; Andersen, Lars L.

2012-01-01

29

Voluntary exercise can strengthen the circadian system in aged mice.  

PubMed

Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2(luc)/C57BL/6) were studied at one of two ages: 3.5 months (n?=?39) and >18 months (n?=?72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n?=?8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption. PMID:23340916

Leise, T L; Harrington, M E; Molyneux, P C; Song, I; Queenan, H; Zimmerman, E; Lall, G S; Biello, S M

2013-01-23

30

Hip Muscle Activity During 3 Side-Lying Hip-Strengthening Exercises in Distance Runners  

PubMed Central

Context: Lower extremity overuse injuries are associated with gluteus medius (GMed) weakness. Understanding the activation of muscles about the hip during strengthening exercises is important for rehabilitation. Objective: To compare the electromyographic activity produced by the gluteus medius (GMed), tensor fascia latae (TFL), anterior hip flexors (AHF), and gluteus maximus (GMax) during 3 hip-strengthening exercises: hip abduction (ABD), hip abduction with external rotation (ABD-ER), and clamshell (CLAM) exercises. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: Twenty healthy runners (9 men, 11 women; age = 25.45 ± 5.80 years, height = 1.71 ± 0.07 m, mass = 64.43 ± 7.75 kg) participated. Intervention(s): A weight equal to 5% body mass was affixed to the ankle for the ABD and ABD-ER exercises, and an equivalent load was affixed for the CLAM exercise. A pressure biofeedback unit was placed beneath the trunk to provide positional feedback. Main Outcome Measure(s): Surface electromyography (root mean square normalized to maximal voluntary isometric contraction) was recorded over the GMed, TFL, AHF, and GMax. Results: Three 1-way, repeated-measures analyses of variance indicated differences for muscle activity among the ABD (F3,57 = 25.903, P<.001), ABD-ER (F3,57 = 10.458, P<.001), and CLAM (F3,57 = 4.640, P=.006) exercises. For the ABD exercise, the GMed (70.1 ± 29.9%), TFL (54.3 ± 19.1%), and AHF (28.2 ± 21.5%) differed in muscle activity. The GMax (25.3 ± 24.6%) was less active than the GMed and TFL but was not different from the AHF. For the ABD-ER exercise, the TFL (70.9 ± 17.2%) was more active than the AHF (54.3 ± 24.8%), GMed (53.03 ± 28.4%), and GMax (31.7 ± 24.1 %). For the CLAM exercise, the AHF (54.2 ± 25.2%) was more active than the TFL (34.4 ± 20.1%) and GMed (32.6 ± 16.9%) but was not different from the GMax (34.2 ± 24.8%). Conclusions: The ABD exercise is preferred if targeted activation of the GMed is a goal. Activation of the other muscles in the ABD-ER and CLAM exercises exceeded that of GMed, which might indicate the exercises are less appropriate when the primary goal is the GMed activation and strengthening.

McBeth, Joseph M.; Earl-Boehm, Jennifer E.; Cobb, Stephen C.; Huddleston, Wendy E.

2012-01-01

31

Influence of gender on the EMG signal of the quadriceps femoris muscles and performance in high-intensity short-term exercise.  

PubMed

The aim of this study was to investigate the influence of gender on the EMG signal of the muscles of the quadriceps femoris and the physical performance in high-intensity, short-term exercise. Fourteen volunteers (7 men = 29.1 +/- 2.8 years and 7 women = 22.6 +/- 2.9 years) performed a Wingate Test (WT) with a load of 7.5% of body mass. The variables analyzed during the WT were the Relative Peak Power (W.Kg(-1)) (RPP), Relative Mean Power (W.Kg(-1)) (RMP), Fatigue Index (%) (FI) and Peak Power Instant (s) (PPI). EMG signals of the superficial muscles of the quadriceps femoris (QF) from the right leg: rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) were analyzed through root mean square (RMS) values and the normalized median frequency (MNF) determined using the Fast Fourier Transform (FFT). The RPP and the RMP were significantly higher in men when compared to women (9.99 +/- 0.96 vs. 7.66 +/- 1.00 W.kg(-1); 7.23 +/- 0.49 vs. 5.65 +/- 0.61 W.kg(1), P < 0.05; respectively). No significant difference between genders was found on RMS and NMF during WT (P > 0.05). Although RPP and RMP were influenced by gender, the RMS and the NMF of the superficial muscles of the QF did not show the same behavior, suggesting that other mechanisms, not related to motor unit recruitment and speed of nervous stimuli in the muscle fiber may be associated to the lower performance of women in high-intensity, short-term exercise. PMID:21284370

Carneiro, J G; Gonçalves, E M; Camata, T V; Altimari, J M; Machado, M V; Batista, A R; Guerra Junior, G; Moraes, A C; Altimari, L R

32

Non-uniform changes in MRI measurements of the thigh muscles following two hamstring strengthening exercises.  

PubMed

ABSTRACT:: Though many different hamstring strengthening exercises exist, the effect on site specific activation of these exercises on different muscles of the leg is unclear. This study investigated the effects of the eccentric leg curl (LC) and lunge (L) exercises on the biceps femoris long head (BFl), biceps femoris short head (BFs), semitendinosus (ST), semimembranosus (SM) and adductor magnus (AM). Each leg of 11 male professional soccer players was randomly assigned to an LC or L exercise protocol (3 sets of 6 repetitions). Functional magnetic resonance imaging (fMRI) of the subjects' thighs were performed before and 48 hours after the intervention. Fifteen axial scans of the thigh interspaced by a distance of 1 / 15 right femur length (Lf) were obtained. The fMRI data were analyzed for signal intensity (SI) changes. No significant changes were observed in absolute short tau inversion recovery (STIR) values for the SM and BFs. Significant changes for the ST (?21-45%) from sections 4 to 10, AM (?2-13%) at section 4, and BFl (? -3 vs 8%) at section 7 were noted. LC exercises load all regions of the ST muscle. L exercises load the proximal regions of the BFl and AM. These findings may have relevance when designing protocols for prevention and rehabilitation of hamstring injuries. PMID:22592171

Mendiguchia, J; Garrues, M A; Cronin, J B; Contreras, B; Arcos, A Los; Malliaropoulos, N; Maffulli, N; Idoate, F

2012-05-15

33

Nonuniform changes in MRI measurements of the thigh muscles after two hamstring strengthening exercises.  

PubMed

Although many different hamstring strengthening exercises exist, the effect on site specific activation of these exercises on different muscles of the leg is unclear. This study investigated the effects of the eccentric leg curl (LC) and lunge (L) exercises on the biceps femoris long head (BFl), biceps femoris short head (BFs), semitendinosus (ST), semimembranosus (SM), and adductor magnus (AM). Each leg of 11 male professional soccer players was randomly assigned to an LC or L exercise protocol (3 sets of 6 repetitions). Functional magnetic resonance imaging (fMRI) of the subjects' thighs were performed before and 48 hours after the intervention. Fifteen axial scans of the thigh interspaced by a distance of 1/15 right femur length (Lf) were obtained. The fMRI data were analyzed for signal intensity changes. No significant changes were observed in absolute short tau inversion recovery values for the SM and BFs. Significant changes for the ST (?21-45%) from sections 4 to 10, AM (?2-13%) at section 4, and BFl (? -3 vs. 8%) at section 7 were noted. LC exercises load all the regions of the ST muscle. The L exercises load the proximal regions of the BFl and AM. These findings may have relevance when designing protocols for prevention and rehabilitation of hamstring injuries. PMID:23443215

Mendiguchia, Jurdan; Garrues, Mirian A; Cronin, John B; Contreras, Bret; Los Arcos, Asier; Malliaropoulos, Nikos; Maffulli, Nicola; Idoate, Fernando

2013-03-01

34

Closed Kinetic Chain exercises with or without additional hip strengthening exercises in management of Patellofemoral pain syndrome: a randomized controlled trial.  

PubMed

Background: Patellofemoral pain syndrome (PFPS) is a common musculoskeletal pain condition, especially in females. Decreased hip muscle strength has been implicated as a contributing factor. Isolated open kinetic chain hip abductors and lateral rotators exercises were added by many authors to the rehabilitation program. However, Closed Kinetic Chain (CKC) exercises focusing on hip and knee muscles were not investigated if they can produce similar effect of hip strengthening and decreasing pain without the need of isolated exercises for hip musculature. Aim: The aim of the present study was to determine the effect of a CKC exercises program with or without additional hip strengthening exercises on pain and hip abductors and lateral rotators peak torque. Design: Prospective randomized clinical trial. Setting: Patients with patellofemoral pain syndrome referred to the outpatient physical therapy clinic of the faculty of physical therapy, cairo university. Population: Thirty two patients who had patellofemoral pain syndrome with age ranged from eighteen to thirty years. Methods: Patients were randomly assigned into two groups: CKC group and CKC with hip muscles strengthening exercises as a control (CO) group. Treatment was given 3 times/week, for 6 weeks. Patients were evaluated pre- and post-treatment for their pain severity using VAS, function of knee joint using Kujala questionnaire, hip abductors and external rotators concentric/eccentric peak torque. Results: There were significant improvements in pain, function and hip muscles peak torque in both groups (P<0.05). However, there was no statistically significant difference between groups in hip muscles torque (P<0.05) but pain and function improvements were significantly greater in the CO group (P<0.05). Conclusion: Six weeks CKC program focusing on knee and hip strengthening has similar effect in improving hip muscles torque in patients with PFPS as a CKC exercises with additional hip strengthening exercises. However, adding isolated hip strengthening exercises has the advantage of more pain relief. Clinical Rehabilitation Impact: CKC exercises with additional hip strengthening could be more beneficial in decreasing pain in PFPS than CKC exercises alone. PMID:23820880

Ismail, M M; Gamaleldein, M H; Hassa, K A

2013-07-02

35

Prospective Evaluation of the Effectiveness of a Home-Based Program of Isometric Strengthening Exercises: 12-Month Follow-up  

PubMed Central

Background The aim of this prospective randomized clinical trial was to investigate the efficacy of a home-based program of isometric strengthening exercises for the treatment of the lateral epicondylitis (LE) of the distal humerus. We hypothesized that 1) use of isometric strengthening exercises would result in clinical benefits similar to those provided by medication and pain relief and 2) functional improvements after exercise would be time-dependent. Methods Patients were assigned to one of two groups: 1) an immediate physical therapy group (group I), or 2) a delayed physical therapy group (group D). Group I patients (n = 16) were instructed how to do the exercises at their first clinic visit and immediately carried out the exercise program. Group D patients (n = 15) learned and did the exercises after being on medications for 4 weeks. Results Outcomes at the 1-month clinic visit indicated that pain (measured using a visual analogue scale [VAS]) had been significantly reduced in group I compared to group D (p < 0.01). However, significant differences between groups were not found at 3-, 6-, and 12-month follow-up for either VAS scores or Mayo elbow performance scores. For modified Nirschl/Pettrone scores, a significant difference between groups was found only at the 1-month follow-up visit. By then, the number of participants who returned to all activities with no pain or occasional mild pain was six (37%) in Group I and two (13%) in Group D (p = 0.031). At the final follow-up visit, 88% of all participants performed physical activities without pain. Conclusions Isometric strengthening exercises done early in the course of LE (within 4 weeks) provides a clinically significant improvement.

Park, Jin-Young; Park, Hong-Keun; Choi, Jin-Hyung; Moon, Eun-Sun; Kim, Byung-Soo; Kim, Wan-Seok

2010-01-01

36

Effect of position and alteration in synergist muscle force contribution on hip forces when performing hip strengthening exercises  

PubMed Central

Background Understanding the magnitude and direction of joint forces generated by hip strengthening exercises is essential for appropriate prescription and modification of these exercises. The purpose of this study was to evaluate hip joint forces created across a range of hip flexion and extension angles during two hip strengthening exercises: prone hip extension and supine hip flexion. Methods A musculoskeletal model was used to estimate hip joint forces during simulated prone hip extension and supine hip flexion under a control condition and two altered synergist muscle force conditions. Decreased strength or activation of specific muscle groups was simulated by decreasing the modeled maximum force values by 50%. For prone hip extension, the gluteal muscle strength was decreased in one condition and the hamstring muscle strength in the second condition. For supine hip flexion, the strength of the iliacus and psoas muscles was decreased in one condition, and the rectus femoris, tensor fascia lata, and sartorius muscles in the second condition. Findings The hip joint forces were affected by hip joint position and partially by alterations in muscle force contribution. For prone hip extension, the highest net resultant force occurred with the hip in extension and the gluteal muscles weakened. For supine hip flexion, the highest resultant forces occurred with the hip in extension and the iliacus and psoas muscles weakened. Interpretation Clinicians can use this information to select exercises to provide appropriate prescription and pathology-specific modification of exercise.

Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.

2009-01-01

37

Oral Rg1 supplementation strengthens antioxidant defense system against exercise-induced oxidative stress in rat skeletal muscles  

PubMed Central

Background Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. Methods Forty weight-matched rats were evenly divided into control (N?=?20) and Rg1 (N?=?20) groups. Rg1 was orally administered at the dose of 0.1?mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats. Results Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of control group, as evidenced by elevated malondialdehyde (MDA) levels. The increased oxidative stress after exercise was also confirmed by decreased reduced glutathione to oxidized glutathione ratio (GSH/GSSG ratio) in control rats. However, these changes were completely eliminated in Rg1 group. Catalase (CAT) and glutathione peroxidase (GPx) activities were significantly (p<0.05) increased by Rg1 in non-exercise rats, while no significant change after exercise. Nevertheless, glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly increased after exercise in Rg1 group. Conclusions This study provide compelling evidences that Rg1 supplementation can strengthen antioxidant defense system in skeletal muscle and completely attenuate the membrane lipid peroxidation induced by exhaustive exercise. Our findings suggest that Rg1 can use as a nutraceutical supplement to buffer the exhaustive exercise-induced oxidative stress.

2012-01-01

38

Muscle activity during leg strengthening exercise using free weights and elastic resistance: effects of ballistic vs controlled contractions.  

PubMed

The present study's aim was to evaluate muscle activity during leg exercises using elastic vs. isoinertial resistance at different exertion and loading levels, respectively. Twenty-four women and eighteen men aged 26-67 years volunteered to participate in the experiment. Electromyographic (EMG) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG. Knee joint angle was measured using electronic inclinometers. The following results were obtained. Loading intensity affected EMG amplitude in the order: lowquadriceps and gluteus EMG amplitude during medium-load ballistic contractions exceeded that recorded during high-load controlled contractions. Quadriceps and gluteus EMG amplitude increased at flexed knee positions. In contrast, hamstrings EMG amplitude remained constant throughout ROM during dumbbell lunge, but increased at more extended knee joint positions during lunges using elastic resistance. Based on these results, it can be concluded that lunges performed using medium-load ballistic muscle contractions may induce similar or even higher leg muscle activity than lunges using high-load slow-speed contractions. Consequently, lunges using elastic resistance appear to be equally effective in inducing high leg muscle activity as traditional lunges using isoinertial resistance. PMID:23231756

Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H; Aagaard, Per; Andersen, Lars L

2012-12-08

39

Home-Based Leg Strengthening Exercise Improves Function One Year After Hip Fracture: A Randomized Controlled Study  

PubMed Central

Objectives Examine the effectiveness of a short term leg strengthening exercise program compared to attentional control on improving strength, walking abilities, and function one year after hip fracture. Design Randomized controlled pilot study. Setting Interventions occurred in patients’ homes. Participants Community-dwelling older adults (n=26) six months post hip fracture at baseline. Intervention Exercise and control participants received interventions by physical therapists twice weekly for 10 weeks. The exercise group received high intensity leg strengthening exercises. The control group received transcutaneous electrical nerve stimulation and mental imagery. Measurements Isometric force production of lower extremity muscles; usual and fast gait speed, six minute walk (6-MW) distance, modified physical performance test (mPPT), and SF-36 physical function. Results The primary endpoint was at one year post fracture. Isometric force production (p<.01), usual and fast gait speed (p=.02 & .03, respectively), 6-MW (p<.01), and mPPT (p<.01) improved at one year post fracture with exercise. Effect sizes were 0.79 for strength, 0.81 for mPPT scores, 0.56 for gait speed, 0.49 for 6-MW, and 0.30 for SF-36 scores. More patients in the exercise group made meaningful changes in gait speed and 6-MW distance than control patients (?2: p=.004). Conclusion A 10-week home-based progressive resistance exercise program was sufficient to achieve moderate to large effects on physical performance and quality of life and may offer an alternative intervention mode for hip fracture patients who are unable to leave home at 6 months after the fracture. The effects were maintained at 3 months after completion of the training program.

Mangione, Kathleen K.; Craik, Rebecca L.; Palombaro, Kerstin M.; Tomlinson, Susan S.; Hofmann, Mary T.

2010-01-01

40

Central and peripheral quadriceps fatigue in congestive heart failure?  

PubMed Central

Aims The clinical syndrome of heart failure includes exercise limitation that is not directly linked to measures of cardiac function. Quadriceps fatigability may be an important component of this and this may arise from peripheral or central factors. Methods and results We studied 10 men with CHF and 10 healthy age-matched controls. Compared with a rest condition, 10 min after incremental maximal cycle exercise, twitch quadriceps force in response to supramaximal magnetic femoral nerve stimulation fell in both groups (CHF 14.1% ± 18.1%, p = 0.037; Control: 20.8 ± 11.0%, p < 0.001; no significant difference between groups). There was no significant change in quadriceps maximum voluntary contraction voluntary force. The difference in the motor evoked potential (MEP) response to transcranial magnetic stimulation of the motor cortex between rest and exercise conditions at 10 min, normalised to the peripheral action potential, also fell significantly in both groups (CHF: 27.3 ± 38.7%, p = 0.037; Control: 41.1 ± 47.7%, p = 0.024). However, the fall in MEP was sustained for a longer period in controls than in patients (p = 0.048). Conclusions The quadriceps is more susceptible to fatigue, with a similar fall in TwQ occurring in CHF patients at lower levels of exercise. This is associated with no change in voluntary activation but a lesser degree of depression of quadriceps motor evoked potential.

Hopkinson, Nicholas S.; Dayer, Mark J.; Antoine-Jonville, Sophie; Swallow, Elisabeth B.; Porcher, Raphael; Vazir, Ali; Poole-Wilson, Philip; Polkey, Michael I.

2013-01-01

41

Effectiveness of home exercise on pain and disability from osteoarthritis of the knee: a randomised controlled trial  

PubMed Central

OBJECTIVE—To assess the effect of a home based exercise programme, designed to improve quadriceps strength, on knee pain and disability.?Methods—191 men and women with knee pain aged 40-80 were recruited from the community and randomised to exercise (n=113) or no intervention (n=78). The exercise group performed strengthening exercises daily for six months. The primary outcome measure was change in knee pain (Western Ontario McMaster Osteoarthritis index (WOMAC)). Secondary measures included visual analogue scales (VAS) for pain on stairs and walking and WOMAC physical function scores.?Results—WOMAC pain score reduced by 22.5% in the exercise group and by 6.2% in the control group (between group difference p<0.05, unpaired t test).VAS scores for pain also reduced in the exercise group compared with the control group (p<0.05). Physical function scores reduced by 17.4% in the exercise group and were unchanged in controls (p<0.05).?Conclusion—A simple programme of home quadriceps exercises can significantly improve self reported knee pain and function.?? Keywords: knee osteoarthritis; knee pain; quadriceps strength; exercise

O'Reilly, S.; Muir, K.; Doherty, M.

1999-01-01

42

Does childhood and adolescence provide a unique opportunity for exercise to strengthen the skeleton?  

PubMed

Osteoporosis is a major, and increasing, public health problem. In this review we examine the evidence that childhood physical activity is an important determinant of bone mineral in adult years, and as such, may help to prevent osteoporosis. Animal studies provide incontrovertible evidence that growing bone has a greater capacity to add new bone to the skeleton than does adult bone. Observational studies in children undertaking routine physical activity and cross-sectional athlete studies in young sportspeople both reveal that activity is positively associated with bone mineral density (BMD). Longitudinal studies in pre- and peripubertal gymnasts reveal BMD gains far in excess of those that can be achieved in adulthood. However, such studies permit only limited conclusions as they contain the potential for selection bias and can be confounded by other determinants of bone mineral (e.g. dietary and lifestyle factors). Thus, research comparing inter-individual playing-to-nonplaying arm differences in bone mineral (e.g., in racquet sports) have proven to be extremely useful. These studies suggest that the BMD differences are clearly greater when bone is subjected to mechanical loading prior to the end of puberty and longitudinal growth of the body (in women, before menarche) rather than after it. Tanner stage II and III appears to be the maturational stage when the association between exercise and BMD becomes manifest in most adolescents. Do conclusions drawn from athlete studies apply to the general population? Randomised intervention studies of physical activity and bone mineral accrual in normal children confirm that childhood activity is strongly associated with bone mineral accrual. Furthermore, some retired athlete studies and a detraining study suggest that adolescent bone gain may, at least partly, persist despite reduced adult physical activity. Mechanisms that may underlie the association between childhood physical activity and bone mineral accrual are outlined. Thus, it appears that physical activity during the most active period of maturity (with respect to longitudinal growth of the body) plays a vital role in optimising peak bone mass and that benefits may extend into adulthood. PMID:11104307

Khan, K; McKay, H A; Haapasalo, H; Bennell, K L; Forwood, M R; Kannus, P; Wark, J D

2000-06-01

43

Electrical stimulation superimposed onto voluntary muscular contraction reduces deterioration of both postural control and quadriceps femoris muscle strength  

Microsoft Academic Search

Fatiguing exercise of the quadriceps femoris muscle degrades postural control in human subjects. The aim of this work was to compare the effects of the fatigue of the quadriceps femoris induced by voluntary muscular contraction (VC), and by electrical stimulation (ES) superimposed onto voluntary muscular contraction (VC+ES), on postural control and muscle strength. Fourteen healthy young adults participated in the

T. Paillard; E. Margnes; J. Maitre; V. Chaubet; Y. François; J. L. Jully; G. Gonzalez; L. Borel

2010-01-01

44

Effect of motor control and strengthening exercises on shoulder function in persons with impingement syndrome: A single-subject study design  

Microsoft Academic Search

The aim of the study was to evaluate the effect of an intervention including shoulder control and strengthening exercises on function in persons with shoulder impingement. Eight subjects with shoulder impingement were evaluated weekly during the nine weeks of this single-subject design study. The study was divided into three phases (A1–B–A2) and involved repeated measures of shoulder pain and function

Jean-Sébastien Roy; Hélène Moffet; Luc J. Hébert; Richard Lirette

2009-01-01

45

Posture Exercises  

MedlinePLUS

... Search You are here Home » Posture Exercises Posture Exercises When a person develops kyphosis, the posture becomes ... and strengthen the back. Try the following two exercises to keep your spine more limber and flexible. ...

46

Concentric and Eccentric Time-Under-Tension during Strengthening Exercises: Validity and Reliability of Stretch-Sensor Recordings from an Elastic Exercise-Band  

PubMed Central

Background Total, single repetition and contraction-phase specific (concentric and eccentric) time-under-tension (TUT) are important exercise-descriptors, as they are linked to the physiological and clinical response in exercise and rehabilitation. Objective To investigate the validity and reliability of total, single repetition, and contraction-phase specific TUT during shoulder abduction exercises, based on data from a stretch-sensor attached to an elastic exercise band. Methods A concurrent validity and interrater reliability study with two raters was conducted. Twelve participants performed five sets of 10 repetitions of shoulder abduction exercises with an elastic exercise band. Exercises were video-recorded to assess concurrent validity between TUT from stretch-sensor data and from video recordings (gold standard). Agreement between methods was calculated using Limits of Agreement (LoA), and the association was assessed by Pearson correlation coefficients. Interrater reliability was calculated using intraclass correlation coefficients (ICC 2.1). Results Total, single repetition, and contraction-phase specific TUT – determined from video and stretch-sensor data – were highly correlated (r>0.99). Agreement between methods was high, as LoA ranged from 0.0 to 3.1 seconds for total TUT (2.6% of mean TUT), from -0.26 to 0.56 seconds for single repetition TUT (6.9%), and from -0.29 to 0.56 seconds for contraction-phase specific TUT (13.2-21.1%). Interrater reliability for total, single repetition and contraction-phase specific TUT was high (ICC>0.99). Interrater agreement was high, as LoA ranged from -2.11 to 2.56 seconds for total TUT (4.7%), from -0.46 to 0.50 seconds for single repetition TUT (9.7%) and from -0.41 to 0.44 seconds for contraction-phase specific TUT (5.2-14.5%). Conclusion Data from a stretch-sensor attached to an elastic exercise band is a valid measure of total and single repetition time-under-tension, and the procedure is highly reliable. This method will enable clinicians and researchers to objectively quantify if home-based exercises are performed as prescribed, with respect to time-under-tension.

Skovdal Rathleff, Michael; Thorborg, Kristian; Bandholm, Thomas

2013-01-01

47

CONTRALATERAL EFFECTS OF DISINHIBITORY TENS ON QUADRICEPS FUNCTION IN PEOPLE WITH KNEE OSTEOARTHRITIS FOLLOWING UNILATERAL TREATMENT  

PubMed Central

Background: Quadriceps activation failure is common in patients with tibiofemoral osteoarthritis (TFOA) and has been reported to occur bilaterally following acute and chronic knee injuries. Sensory transcutaneous electrical stimulation (TENS) applied to the knee has increased ipsilateral quadriceps activation, yet it remains unknown if repeated sensory TENS treatments affect activation in the contralateral quadriceps. Objective: To determine the effects of unilateral TENS treatment to the involved leg, in conjunction with 4-weeks of therapeutic exercise, on volitional quadriceps activation in the contralateral leg. Methods: Thirty-three patients with radiographically diagnosed TFOA were randomly assigned to the TENS, placebo, and the control groups. The involved leg was defined as the knee with highest degree of radiographically assessed TFOA. All participants completed a supervised 4-week lower extremity exercise program for the involved leg only. TENS and placebo TENS were worn throughout the rehabilitation sessions as well as during daily activities for those groups on the involved leg. Quadriceps central activation ratio (CAR), a measure of volitional muscular activation, was assessed in the uninvolved leg at baseline, 2-weeks and 4-weeks following the initiation of the intervention. Results: There were no differences between groups for quadriceps CAR (P=0.3). Discussion: Although significant differences were not found, strong to moderate within group effect sizes were calculated for the TENS group at 2 (d = .87) and 4 weeks (d = .54), suggesting that significant differences may be found in a larger population. Conclusions: Contralateral quadriceps CAR was not affected following a 4-week unilateral disinhibitory intervention in this sample.

Saliba, Susan A.; Hart, Joseph M.; Hertel, Jay; Ingersoll, Christopher D.

2010-01-01

48

Exercise  

MedlinePLUS

... Hip Knee Ankle Foot, Heel, & Toe View All Exercise Videos From yoga to strength training, get step- ... to your inbox. Sign up now. Read More Exercise Overview Exercise is an essential part of treatment ...

49

Exercise \\  

Microsoft Academic Search

FOCUS POINTS • Exercise behavior occurs commonly in anorexia nervosa (AN) and appears to be highly reinforcing to individuals with this disorder. • Authors adapted a clinical survey used to mea- sure dependence to drugs of abuse to assess exercise behavior among subjects with AN. • Forty-eight percent of individuals assessed endorsed symptoms consistent with exercise dependence in the previous

Diane A. Klein; Andrew S. Bennett; Janet Schebendach; Richard W. Foltin; Michael J. Devlin; B. Timothy Walsh

2004-01-01

50

Why Exercise Is Cool  

MedlinePLUS

... day and your body will thank you later! Exercise Makes Your Heart Happy You may know that ... rope, and playing hopscotch are aerobic activities, too! Exercise Strengthens Muscles Another kind of exercise can help ...

51

Strengthening Chv\\  

Microsoft Academic Search

Chv( atal-Gomory and Gomory fractional cuts are well-known cutting planes for pure integer programming problems. Various methods for strengthening them are known, for example based on subadditive functions or disjunctive techniques. We present a new and surprisingly simple strengthening procedure, discuss its properties, and present some computational results. c ? 2002 Elsevier Science B.V. All rights reserved.

Adam N. Letchford; Andrea Lodi

52

Eccentric and concentric isokinetic moment characteristics in the quadriceps and hamstrings of the chronic isolated posterior cruciate ligament injured knee  

PubMed Central

OBJECTIVE: Functional strength deficits associated with chronic isolated posterior cruciate ligament (PCL) insufficiency have received limited attention in the literature. The purpose of this study was to determine the eccentric and concentric isokinetic moment characteristics of the quadriceps and hamstrings in a sample of patients with isolated PCL injury. METHODS: Eccentric and concentric mean average and average peak moments were measured for 17 patients with a history of conservatively treated isolated PCL injury using an isokinetic dynamometer. Quadriceps and hamstring isokinetic moments were recorded from 10 degree to 90 degree of knee flexion. Strength ratios were calculated and compared with those reported in the literature for healthy subjects. RESULTS: The hamstrings of the involved side (eccentric/concentric (E/C) ratio = 1.06) were significantly weaker (p<0.05) eccentrically than those of the contralateral side (E/C ratio = 1.29). All hamstrings/quadriceps (H/Q) ratios were less than the universally accepted value of 0.60 and the eccentric H/Q ratio for the injured extremity was significantly lower than the non-injured (p<0.05). In a bilateral comparison, the injured/non-injured (I/N) ratio was less than 1.00 for concentric quadriceps, eccentric quadriceps, and hamstring isokinetic moments. Calculation of the E/C ratio showed that, for the quadriceps, it was 1.08 on the injured side and 1.07 on the non-injured extremity. CONCLUSIONS: Eccentric strengthening should be an integral part of functionally rehabilitating the quadriceps and hamstrings of athletes who suffer from the complications associated with chronic isolated PCL insufficiency. ???

MacLean, C. L.; Taunton, J. E.; Clement, D. B.; Regan, W.

1999-01-01

53

Intramuscular Ganglion of the Quadriceps Femoris  

PubMed Central

Ganglion cysts are common lesions that are most often found around the joints of the hands and feet. Ganglia around the distal femur usually occur within the synovial membrane or tendon sheath, but rarely within muscles. Several cases of intramuscular ganglions in the hand and wrist have been reported, but a ganglion cyst in the quadriceps muscle has rarely been addressed in studies. In this report, we present a 17-year-old patient with a painful movable mass in the intramuscular area of the quadriceps femoris that was diagnosed by ultrasound and treated by excision and biopsy.

Kim, Yeung Jin; Chae, Soo Uk; Kim, Jong Yun; Jo, Hyang Jeong

2013-01-01

54

Impact of external resistance and maximal effort on force-velocity characteristics of the knee extensors during strengthening exercise: a randomized controlled experiment.  

PubMed

It remains controversial whether maximal effort attained by high external resistance is required to optimize muscle adaptation to strengthening exercise. Here, we compared different training protocols reaching maximal effort with either high-resistance (HImax, 80% of 1-repetition maximum [1RM]) or low-resistance (LOmax, ?40% 1RM). Thirty-six young volunteers were randomly assigned to 9 weeks of leg extension training at either HImax (1 set of 10-12 repetitions at 80% 1RM), LO (1 set of 10-12 repetitions at 40% 1RM, no maximal effort), or LOmax (1 set of 10-12 repetitions at 40% 1RM, preceded [no rest] by 60 repetitions at 20-25% 1RM). Knee extension 1RM was measured preintervention and postintervention and before the 7th, 13th, and 19th training sessions. Preintervention and postintervention, knee extensor static (PTstat) and dynamic (PTdyn) peak torque, maximal work (MW), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat were recorded with a Biodex dynamometer. All the groups showed a significant increase in 1RM, with a greater improvement in HImax from the 13th session on (p < 0.05). The HImax was the only group that significantly increased PTstat (+7.4 ± 8.1%, p = 0.01). The LOmax showed a significantly greater increase in S20 (+6.0 ± 3.2%), PTdyn (+9.8 ± 5.6%), and MW (+15.1 ± 10.6%) than both HImax and LO (p = 0.044 for S20, p = 0.030 for PTdyn, p = 0.025 for MW) and was the only group that increased in S40 (+7.7 ± 9.7%, p = 0.032). In conclusion, significant differences between HImax and LOmax on force-velocity characteristics of the knee extensors were found, although maximal effort was achieved in both training regimens. Thus, LOmax may not be considered as a replacement for HImax but rather as an alternative with different training-specific adaptations. PMID:22692123

Van Roie, Evelien; Bautmans, Ivan; Boonen, Steven; Coudyzer, Walter; Kennis, Eva; Delecluse, Christophe

2013-04-01

55

Exercise  

MedlinePLUS

... better bladder and bowel function, less fatigue and depression, a more positive attitude, and increased participation in social activities. Since 1996, several additional studies have confirmed the benefits of exercise. Inactivity in people with or without MS can ...

56

Exercise  

MedlinePLUS

... part of any spondylitis program, along with good posture habits and medication to reduce pain and stiffness. ... spondylitis exercise program will help you maintain good posture, flexibility and eventually help to lessen pain. In ...

57

Isokinetic Hamstrings: Quadriceps Ratios in Intercollegiate Athletes.  

ERIC Educational Resources Information Center

|Compared the differences in the concentric hamstrings to quadriceps (H:Q) ratio among athletes in different sports at three velocities. Measurement of H:Q ratio of both knees among male and female college athletes indicated that the H:Q ratio increased as velocity increased. No differences existed for the H:Q ratio for sport or side of body. (SM)|

Rosene, John M.; Fogarty, Tracey D.; Mahaffey, Brian L.

2001-01-01

58

Exercise  

Microsoft Academic Search

Many athletes, especially female athletes and participants in endurance and aesthetic sports and sports with weight classes, are chronically energy deficient. This energy deficiency impairs performance, growth and health. Reproductive disorders in female athletes are caused by low energy availability (defined as dietary energy intake minus exercise energy expenditure), perhaps specifically by low carbohydrate availability, and not by the stress

F A Hellebrandt

1940-01-01

59

Measurement of quadriceps endurance by fNIRS  

NASA Astrophysics Data System (ADS)

In this paper, the changes in muscle deoxygenation trends during a sustained isometric quadriceps (chair squat/half squat) endurance exercise were evaluated among twelve male subjects and the relationship between muscle oxygenation and endurance times was investigated by means of functional near-infrared spectroscopy (fNIRS). Neuromuscular activation and predictions of muscle performance decrements during extended fatiguing task was investigated by means of surface electromyography (sEMG). The results of the study showed that in the subjects who maintained exercise longer than five minutes (group 1), mean Hb recovery time (33 [sec.]) was 37.4% less than the others (group 2, 52.7 [sec.]). Also mean HbO2 decline amplitude (2.53 [a.u.] in group 1 and 2.07 [a.u.] in group 2) and oxy decline amplitude (8.4 [a.u.] in group 1 and 3.04 [a.u.] in group 2) in the beginning of squat exercise are found to be 22.6% and 176.9% bigger in these group. For the EMG parameters, mean slope of MNF and MDF decline are found to be 57.5% and 42.2% bigger in magnitude in group 2 which indicates higher degree of decrement in mean and median frequencies although their mean squat duration time is less. This indicates higher index of fatigue for this group. It is concluded that training leads to altered oxygenation and oxygen extraction capability in the exercising muscle and investigated fNIRS parameters could be used for endurance evaluation.

Erdem, Devrim; ?ayli, Ömer; Karahan, Mustafa; Akin, A.

2006-03-01

60

Isometric exercise (image)  

MedlinePLUS

Isometric exercise works muscles and strengthens bone. Increased muscle mass elevates metabolism, which in turn burns fat. Strength training is also called anaerobic exercise, as opposed to aerobic, because ...

61

Self-regulatory skills usage strengthens the relations of self-efficacy for improved eating, exercise, and weight in the severely obese: toward an explanatory model.  

PubMed

Lack of success with behavioral weight-management treatments indicates a need for a better understanding of modifiable psychological correlates. Adults with class 2 and 3 obesity (N = 183; Mean(BMI) = 42.0 kg/m(2)) volunteered for a 26-week nutrition and exercise treatment, based on social cognitive theory, that focused on self-efficacy and self-regulation applied to increasing cardiovascular exercise and fruit and vegetable consumption. Improved self-efficacy for controlled eating significantly predicted increased fruit and vegetable consumption (R(2) = .15). Improved self-efficacy for exercise significantly predicted increased exercise (R(2) = .46). When changes in self-regulatory skill usage were stepped into the 2 previous equations, the variances accounted for significantly increased. Increases in fruit and vegetable consumption and exercise significantly predicted weight loss (R(2) = .38). Findings suggest that behavioral theory should guide research on weight-loss treatment, and a focus on self-efficacy and self-regulatory skills applied to specific nutrition and exercise behaviors is warranted. PMID:21895423

Annesi, James J

2011-07-01

62

Stimulated and voluntary fatiguing contractions of quadriceps femoris differently disturb postural control.  

PubMed

Muscle fatigue affects muscle strength and postural control. However, it is not known whether impaired postural control after fatiguing muscular exercise depends on the nature of the muscle contraction. To answer this question, the present study analyzes changes in postural control after two fatiguing exercises of equal duration and intensity but that induced different magnitudes of strength loss. The effects of fatiguing contractions of the femoris quadriceps were compared for voluntary muscular contraction (VOL) and neuromuscular electrical stimulation (ES) on muscle strength and postural control. Seventeen subjects completed these two fatiguing exercises. Maximal voluntary contraction (MVC) and postural control were recorded using an isokinetic dynamometer and a force platform that recorded the center of foot pressure. Recordings were performed before and after the completion of both fatiguing tasks. Results indicate that, after a fatiguing exercise, the ES exercise affected MVC more than the VOL exercise. Inversely, postural control was disturbed more after VOL exercise than after ES exercise. In conclusion, postural control disturbance is influenced by the nature of the muscular contraction (voluntary vs. non-voluntary) and the type of the motor unit solicited (tonic vs. phasic) rather than by the magnitude of strength loss. PMID:20417250

Paillard, Thierry; Maitre, Julien; Chaubet, Vincent; Borel, Liliane

2010-04-22

63

Stimulated and voluntary fatiguing contractions of quadriceps femoris similarly disturb postural control in the bipedal stance.  

PubMed

The aim of this work was to compare the effects of fatigue of the quadriceps femoris after fatiguing voluntary contractions (VOL) and fatiguing neuromuscular electrical stimulation (ES) on bipedal postural control. Nineteen active male subjects (22.2 ± 1.7 years) completed these two fatiguing exercises. Isometric maximal voluntary contraction (MVC) and postural control were recorded using an ergometer and a force platform that registered the center of foot pressure (COP). We analyzed the COP surface, the mean COP velocity and the spectral power density given by the wavelet transform. Recordings were performed before (PRE condition) and after the completion of each fatiguing task (immediately POST condition, after a 5 min recovery POST 5 condition). In POST condition, the ES exercise affected MVC more than the VOL exercise. However, bipedal postural control was similarly deteriorated for both exercises. In POST 5 condition, for both fatiguing exercises, muscle strength and postural control did not recover their initial level. These results suggest that the postural control disturbance could not be distinguished for the two fatiguing exercises in the bipedal stance. In addition, the recovery speeds of postural control and muscle strength abilities did not differ for the ES exercise and the VOL exercise. PMID:21922258

Chaubet, Vincent; Maitre, Julien; Cormery, Bruno; Paillard, Thierry

2011-09-16

64

Eccentric Strengthening for Chronic Lateral Epicondylosis  

PubMed Central

Background: Effective treatments for chronic lateral epicondylosis have not been studied adequately. Eccentric overload exercises have been used with success for other chronic tendinopathy, mainly Achilles and patellar. Hypothesis/Purpose: To compare a wrist extensor eccentric strengthening exercise program with a wrist extensor stretching/modality program for the treatment of chronic lateral epicondylosis. The authors hypothesized that the eccentric strengthening program would produce more favorable results than a stretching/modality program. Study Design: Prospective randomized controlled trial. Methods: Twenty-eight adults with lateral epicondylosis of greater than 4 weeks’ duration were randomized to an eccentric strengthening group or a stretching group. Exercises were taught by a physical therapist, and participants performed most of the exercises on their own at home. Pain scores with visual analog scale from 0 to 100 were obtained at baseline and then at 4, 8, 12, 16, and 20 weeks after the start of the exercise program. Results: Both groups improved their pain scores from baseline to the 4-week time point, followed by nonsignificant further decreases in pain scores thereafter. No statistically significant differences were found between the eccentric strengthening group and stretching groups at any follow-up time point. Conclusions: Despite previous reports documenting favorable results with eccentric exercises for other tendinopathy, the authors were unable to show any statistical advantage to eccentric exercises for lateral epicondylosis during these periods compared with local modalities and stretching exercises.

Wen, Dennis Y.; Schultz, Brian J.; Schaal, Bob; Graham, Scott T.; Kim, Byung Sung

2011-01-01

65

Development and delivery of an exercise intervention for rheumatoid arthritis: strengthening and stretching for rheumatoid arthritis of the hand (SARAH) trial.  

PubMed

This paper describes the development and implementation of a hand exercise intervention for rheumatoid arthritis (RA) as part of a large multi-centred randomised controlled trial in a U.K. National Health Service (NHS) setting. Participants are eligible if diagnosed with RA according to American College of Rheumatology criteria, have a history of disease activity, functional deficit or impairment in the hand and/or wrist, and have been on a stable medication regime for at least 3 months. The intervention development was informed by the current evidence base, published guidelines, clinician and expert opinion, and a pilot study. The exercise programme targets known, potentially modifiable physical impairments of the hand with 5 exercise sessions and a home exercise component over a 12 week period. The intervention will be provided to 240 participants along with usual care. A further 240 will receive usual care only as part of the control arm. Specific details of the treatments delivered are described. [ISRCTN no: 89936343]. PMID:22507362

Heine, P J; Williams, M A; Williamson, E; Bridle, C; Adams, J; O'Brien, A; Evans, D; Lamb, S E

2012-06-01

66

Differential effect of knee extension isometric training on the different muscles of the quadriceps femoris in humans  

Microsoft Academic Search

This study determined the effects of a short period of knee isometric training on the quadriceps muscles accessible to surface\\u000a electromyography (EMG). For this purpose, a training (n=9) and a control (n=7) group were tested on five identical occasions at 1?week intervals during 4?weeks. The training group exercised three times\\u000a a week by making isometric knee extensions at 80% of

Giuseppe Rabita; Chantal Pérot; Ghislaine Lensel-Corbeil

2000-01-01

67

Bilateral simultaneous rupture of the quadriceps tendons.  

PubMed

Bilateral simultaneous rupture of the quadriceps tendons is very rare and occurred in an 82-year-old man. This may be the fifth case to have been reported in the English literature. Only minor stress on extensor mechanisms preceded the ruptures. Interrupted mattress sutures restored muscle continuity and function. A "pull-out" wire system was not used for protection of healing muscles because adequate amount of tissue mass was available for approximation. Excellent results require intensive postoperative physical therapy. Old age of the patient should not be a deterrent to surgical treatment in carefully selected individuals. PMID:657630

Siwek, K W; Rao, J P

68

Quadriceps myofibrosis. A complication of intramuscular injections.  

PubMed

Cases of fibrofatty replacement of the quadriceps muscles following repeated intramuscular injections into the thighs of infants and young children are being reported with increasing frequency. In such cases, the knee shows progressive painless limitation of flexion, habitual dislocation of the patella, or both. The recommended treatment is surgical release, done early before secondary adaptive changes occur in the soft tissues, cartilage, and bones comprising the joint. Full flexion should be obtained at the time of surgery. In children, the lag in extension that follows extensive release will usually disappear spontaneously. PMID:7351417

Alvarez, E V; Munters, M; Lavine, L S; Manes, H; Waxman, J

1980-01-01

69

Bilateral rectus femoris intramuscular haematoma following simultaneous quadriceps strain in an athlete: a case report  

PubMed Central

Introduction Bilateral rectus femoris haematoma following a simultaneous strain of the quadriceps muscles is a very rare condition. Case presentation We report the case of a 21-year-old Greek Caucasian female rowing athlete who was injured on both thighs. She complained of pain and inability to walk. Physical examination revealed tenderness over the thighs and restriction of knee movement. The result of a roentgenogram was normal, and there was no evidence of fracture or patella displacement. Magnetic resonance imaging revealed haematoma formation in both the rectus femoris muscles. The diameters of the left and right haematomas within the muscles were 6 cm and 5 cm, respectively. Therapeutic approaches included compression bandages, ice application, rest, elevation, and administration of muscle relaxant drugs. Active stretching and isometric exercises were performed after three days. The patient was able to walk using crutches two days after the initiation of treatment. On the seventh day, she had regained her full ability to walk without crutches. Non-steroidal anti-inflammatory drugs were administered on the fifth day and continued for one week. Six weeks later, she had pain-free function and the result of magnetic resonance imaging was normal. She was able to resume her training programme and two weeks later, she returned to her previous sport activities and competitions. Conclusion There are references in the literature regarding the occurrence of unilateral quadriceps haematomas following strain and bilateral quadriceps tendon rupture in athletes. Simultaneous bilateral rectus femoris haematomas after a muscle strain is a rare condition. It must be diagnosed early. The three phases of treatment are rest, knee mobilization, and restoration of quadriceps function.

2010-01-01

70

Abdominal muscle and quadriceps strength in chronic obstructive pulmonary disease  

Microsoft Academic Search

Background: Quadriceps muscle weakness is common in chronic obstructive pulmonary disease (COPD) but is not observed in a small hand muscle (adductor pollicis). Although this could be explained by reduced activity in the quadriceps, the observation could also be explained by anatomical location of the muscle or fibre type composition. However, the abdominal muscles are of a similar anatomical and

W D-C Man; N S Hopkinson; F Harraf; D Nikoletou; M I Polkey; J Moxham

2005-01-01

71

Simultaneous bilateral quadriceps tendon rupture while playing basketball  

Microsoft Academic Search

Simultaneous bilateral quadriceps tendon rupture is an uncommon injury in healthy people and only a few cases have been reported in athletes. This is the first report of a patient with simultaneous bilateral quadriceps tendon rupture incurred while playing basketball. The injury was surgically repaired and the patient had a good functional outcome.

M Shah; N Jooma

2002-01-01

72

Inhibition of the quadriceps muscles in elite male volleyball players  

Microsoft Academic Search

Inhibition of the quadriceps muscles was assessed in 13 elite male volleyball players using the interpolated twitch technique. This technique involves applying an electrical stimulus to the voluntarily contracted quadriceps muscles to estimate the number of motor units not fully activated during the contraction. Knee extensor moments and muscle inhibition were measured during isometric contractions at knee angles of 30

E. Suter; W. Werzog

1998-01-01

73

Diagnosis and management of quadriceps strains and contusions  

PubMed Central

Injuries to the quadriceps muscle group occur frequently in sports and athletic activities. Muscle strains and contusions constitute the majority of these injuries. The clinical presentation and assessment of quadriceps strains and contusions are reviewed along with discussion of appropriate imaging used in diagnosis. Treatment protocols for acute injuries are reviewed including rehabilitation techniques frequently utilized during recovery. Special consideration is given to discussing the criteria for return to sports for athletes after injury. Myositis ossificans is a potentially disabling complication from quadriceps contusions and risk factors, prevention, and treatment are reviewed.

2010-01-01

74

Characterization of the human quadriceps muscle in active elders  

Microsoft Academic Search

Stevens JE, Binder-Macleod S, Snyder-Mackler L. Characterization of the human quadriceps muscle in active elders. Arch Phys Med Rehabil 2001;82:973-8. Objective: To compare muscle activation deficits and muscle physiology in older versus younger adults. Design: A maximal volitional isometric contraction of the quadriceps muscle with burst-superimposition was used to assess strength and activation. In addition, force-frequency testing during fresh, fatigue,

Jennifer E. Stevens; Stuart Binder-Macleod; Lynn Snyder-Mackler

2001-01-01

75

Diagnosis and management of quadriceps strains and contusions  

Microsoft Academic Search

Injuries to the quadriceps muscle group occur frequently in sports and athletic activities. Muscle strains and contusions\\u000a constitute the majority of these injuries. The clinical presentation and assessment of quadriceps strains and contusions are\\u000a reviewed along with discussion of appropriate imaging used in diagnosis. Treatment protocols for acute injuries are reviewed\\u000a including rehabilitation techniques frequently utilized during recovery. Special consideration

Joel M. Kary

2010-01-01

76

The Protonics Knee Brace Unloads the Quadriceps Muscles in Healthy Subjects  

PubMed Central

Objective: The Protonics brace is a functional resistance brace designed for rehabilitative use in patients with patellofemoral pain syndrome. Our objective was to determine whether the Protonics brace altered quadriceps muscle activity or knee mechanics in healthy subjects. Design and Setting: We used a within-subjects design in a laboratory setting. Subjects: Nineteen recreationally active college students (10 females, 9 males; age = 22.6 ± 2.8 years; height = 172 ± 9.0 cm, mass = 69.7 ± 12.5 kg) with no history of patellofemoral pain syndrome. Measurements: A standard-length Protonics brace was fit to each subject's leg. Surface electromyography of the vastus medialis obliquus, vastus lateralis, and rectus femoris muscles was recorded during a lateral step-down exercise. Lower extremity kinematics and ground reaction force were assessed during stair descent. Subjects performed both tasks under 4 conditions: no brace and brace with low, medium, and high resistance. Electromyography values were normalized to a maximum voluntary isometric contraction. The brace moment was determined by passive testing in an isokinetic dynamometer. Changes in the subject's muscular knee-extension moment were determined by subtracting the extension moment provided by the brace from the total knee-extension moment calculated from motion and force data using an inverse dynamics approach. Results: Vastus medialis obliquus activity in the brace at the low- and medium-resistance settings was significantly lower than that measured without the brace. Vastus lateralis activity while wearing the brace at medium resistance was significantly less than in the absence of the brace. Regardless of brace setting, vastus medialis obliquus and vastus lateralis activity in the descending phase of the exercise was less than during the ascending phase. A significant interaction was noted between brace setting and phase of the step-down exercise for rectus femoris activity. Significantly less activity was seen in the descending phase than in the ascending phase. Post hoc testing indicated that, in the descending phase, less activity was demonstrated with the brace at the medium and high settings than at the low setting. Muscle activity at the high setting and activity at low resistance were also significantly less than when the brace was not worn in the ascending phase. Knee flexion and extension moment during stair descent were significantly less at the higher resistance settings. Conclusions: Wearing the Protonics brace at moderate or high resistance during the lateral step-down exercise produced less quadriceps activity compared with not wearing the brace. The knee extensor mechanism was unloaded when the brace was worn during stair descent. These findings indicate that the Protonics brace may unload the quadriceps and therefore decrease the load on the patellofemoral joint.

Piazza, Stephen J.; Hertel, Jay

2004-01-01

77

The Protonics Knee Brace Unloads the Quadriceps Muscles in Healthy Subjects.  

PubMed

OBJECTIVE: The Protonics brace is a functional resistance brace designed for rehabilitative use in patients with patellofemoral pain syndrome. Our objective was to determine whether the Protonics brace altered quadriceps muscle activity or knee mechanics in healthy subjects. DESIGN AND SETTING: We used a within-subjects design in a laboratory setting. SUBJECTS: Nineteen recreationally active college students (10 females, 9 males; age = 22.6 +/- 2.8 years; height = 172 +/- 9.0 cm, mass = 69.7 +/- 12.5 kg) with no history of patellofemoral pain syndrome. MEASUREMENTS: A standard-length Protonics brace was fit to each subject's leg. Surface electromyography of the vastus medialis obliquus, vastus lateralis, and rectus femoris muscles was recorded during a lateral step-down exercise. Lower extremity kinematics and ground reaction force were assessed during stair descent. Subjects performed both tasks under 4 conditions: no brace and brace with low, medium, and high resistance. Electromyography values were normalized to a maximum voluntary isometric contraction. The brace moment was determined by passive testing in an isokinetic dynamometer. Changes in the subject's muscular knee-extension moment were determined by subtracting the extension moment provided by the brace from the total knee-extension moment calculated from motion and force data using an inverse dynamics approach. RESULTS: Vastus medialis obliquus activity in the brace at the low- and medium-resistance settings was significantly lower than that measured without the brace. Vastus lateralis activity while wearing the brace at medium resistance was significantly less than in the absence of the brace. Regardless of brace setting, vastus medialis obliquus and vastus lateralis activity in the descending phase of the exercise was less than during the ascending phase. A significant interaction was noted between brace setting and phase of the step-down exercise for rectus femoris activity. Significantly less activity was seen in the descending phase than in the ascending phase. Post hoc testing indicated that, in the descending phase, less activity was demonstrated with the brace at the medium and high settings than at the low setting. Muscle activity at the high setting and activity at low resistance were also significantly less than when the brace was not worn in the ascending phase. Knee flexion and extension moment during stair descent were significantly less at the higher resistance settings. CONCLUSIONS: Wearing the Protonics brace at moderate or high resistance during the lateral step-down exercise produced less quadriceps activity compared with not wearing the brace. The knee extensor mechanism was unloaded when the brace was worn during stair descent. These findings indicate that the Protonics brace may unload the quadriceps and therefore decrease the load on the patellofemoral joint. PMID:15085211

Earl, Jennifer E.; Piazza, Stephen J.; Hertel, Jay

2004-03-01

78

An exercise professional led, community based, dietary and exercise programme for knee osteoarthritis.  

PubMed

NICE guidance stipulates exercise and weight loss as 'Core' treatments for Osteoarthritis (OA). Typically, NHS physiotherapists and dieticians deliver these treatments within the secondary health care setting. Given increasing demands placed upon secondary health care professionals, we conducted a novel, community based, registered exercise professional led, exercise and dietary intervention in obese patients with established knee OA, to evaluate its efficacy and potentially widespread use within the National Exercise Referral Scheme in Wales. 81 patients (BMI<30) with knee OA were invited (mean age 57 y, BMI 39.5 kg/m(2)) from Orthopaedic, Rheumatology and Primary care settings. 58 patients declined to take part. 1 patient was excluded at assessment due to medical concerns. The pilot was a 16 week dietary and exercise programme delivered in the community setting. Patients performed 2 x1 hour per week of a 10-station exercise carousel incorporating aerobic and resistance exercise aimed at quadriceps and hamstring strengthening. 1 hour per week of dietary education was given, using Public Health Wales' 'Foodwise for Life' programme, and 3 sessions of practical cooking skills over 16 weeks. Primary outcome measures were the Oxford Knee Score (OKS); Quality of Life (QoL) (EQ-5D+EQ-VAS); physical function (6 minute walk test (6MWT) and 30 second sit-stand (30 s s-s)). Secondary measures; body weight; resting Blood Pressure(BP); resting heart rate (RHR). 18 patients completed the 16 week programme. Improvements were seen in OKS (p=0.048), 6MWT (p<0.001), 30 s s-s (p<0.001), EQ-VAS (p=0.01), weight (p=0.001) and systolic BP (p<0.001). No significant improvements were seen in diastolic BP (p=0.96), RHR (p=0.11) and EQ-5D (p=0.11). This pilot suggests a community based, exercise professional led intervention for patients with knee OA as a clinically effective therapeutic resource for health professionals. PMID:24159139

Evans, D; Gibbons, D; Hazard, N; Williams, R; Jones, A; Martin, R

2013-11-01

79

Sex differences in quadriceps strength in OA.  

PubMed

The purposes of this study were to determine 1) whether sex differences in quadriceps torque and isotonic power persist when controlling for muscle volume (i.?e., torque/muscle volume and power/muscle volume) in participants with knee osteoarthritis (OA) and 2) the factors responsible for potential sex differences. Isometric torque, isotonic power (the product of torque and velocity, measured at 10, 20, 30, 40 and 50% maximal voluntary contraction; MVC) and maximal unloaded velocity were assessed in men (n=16, mean age=62.1 ± 7.2) and women (n=17, mean age=60.4 ± 4.3) with knee OA. Torque and power were normalized to muscle volume. The interpolated twitch technique was used to measure voluntary activation (VA) and evoked twitch and torque-frequency characteristics were measured to obtain information about muscle fibre distribution. Torque and power at all loads were significantly lower in women (p<0.05). Sex differences in power were reduced by 50% when controlling for muscle volume but were still significant at 10-40% MVC (p<0.05). No differences in VA, torque-frequency properties or time-to-peak tension of the evoked twitch were observed (p>0.05). These results suggest that only minor sex differences in torque and power persist when controlling for muscle volume. As VA and contractile property differences were not observed, other factors seem to be responsible. PMID:22706942

Berger, M J; McKenzie, C A; Chess, D G; Goela, A; Doherty, T J

2012-06-15

80

A method of repair of late quadriceps rupture.  

PubMed

Delayed treatment of a quadriceps rupture is an infrequent but difficult situation. The fibrous degeneration and muscle retraction and subsequent hiatus present a challenging technical problem. A 54-year-old laborer with a 7-week quadriceps rupture was treated by a method that seems not to have been previously reported. At surgery there was a 9-cm gap that could not be approximated by either a Bunnell suture, or Codvilla lengthening of Scuderi inverted triangle. Repair was successfully accomplished by transposing the inner one-third of the patellar tendon. The tendon was split longitudinally and separated from the medial and lateral aspects in a distal to proximal direction with an osteoperiosteal flap. This was proximally sutured across the gap in the quadriceps mechanism. Eighteen months postoperatively there was no extension lag with knee range of motion of 0 degrees-125 degrees and good power. PMID:7371293

Chekofsky, K M; Spero, C R; Scott, W N

81

Sports Massage after Eccentric Exercise  

Microsoft Academic Search

Background: The use of sports massage is very common in the athletic community. However, only a few studies have shown any therapeutic effect of massage.Hypothesis: Sports massage can improve the recovery after eccentric exercise.Study Design: Prospective randomized clinical trial.Methods: Sixteen subjects performed 300 maximal eccentric contractions of the quadriceps muscle bilaterally. Massage was given to 1 leg, whereas the other

Sven Jönhagen; Paul Ackermann; Tommy Eriksson; Tönu Saartok; Per A. F. H. Renström

2004-01-01

82

Strain within the anterior cruciate ligament during hamstring and quadriceps activity  

Microsoft Academic Search

The objectives of this study were to measure strain in the ACL during simulated: (1) hamstring activity alone, (2) quadriceps activity alone, and (3) simultaneous quadriceps and hamstring activity. Seven knee speci mens removed from cadavers were studied. Heavy sutures applied to load cells were attached to the hamstring and quadriceps tendons. Loads were then applied manually (hamstrings) and\\/or with

P. Renström; S. W. Arms; T. S. Stanwyck; R. J. Johnson; M. H. Pope

1986-01-01

83

Reliability of surface EMG during sustained contractions of the quadriceps  

Microsoft Academic Search

The purpose of this study was to determine test–retest reliability for median frequency (MDF) and amplitude of surface EMG during sustained fatiguing contractions of the quadriceps. Twenty-two healthy subjects (11 males and 11 females) were tested on two days held one week apart. Surface EMG was recorded from rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) during sustained

S. Mathur; J. J. Eng; D. L. MacIntyre

2005-01-01

84

Myogenic regulatory factor response to resistance exercise volume in skeletal muscle  

Microsoft Academic Search

This study examined the impact of resistance exercise volume on myoD and myogenin in rodent quadriceps muscle. Six-month-old\\u000a male Sprague–Dawley rats (316 ± 2 g) performed either low-volume (LV; 10 sets × 10 contractions) or high-volume (HV; 20 sets × 10\\u000a contractions) resistance exercise at 75% one-repetition maximum. Muscles were analyzed for myogenin and myoD mRNA and protein\\u000a expression 6, 12, 24 and 48 h post-exercise. In red quadriceps

Micah J. Drummond; Robert K. Conlee; Gary W. Mack; Sterling Sudweeks; G. Bruce Schaalje; Allen C. Parcell

2010-01-01

85

Quadriceps Activation Failure After Anterior Cruciate Ligament Rupture Is Not Mediated by Knee Joint Effusion  

PubMed Central

STUDY DESIGN Descriptive prospective cohort study. OBJECTIVES To investigate the relationships between knee joint effusion, quadriceps activation, and quadriceps strength. These relationships may help clinicians better identify impaired quadriceps activation. BACKGROUND After anterior cruciate ligament (ACL) injury, the involved quadriceps may demonstrate weakness. Experimental data have shown that quadriceps activation and strength may be directly mediated by intracapsular joint pressure created by saline injection. An inverse relationship between quadriceps activation and the amount of saline injected has been reported. This association has not been demonstrated for traumatic effusion. We hypothesized that traumatic joint effusion due to ACL rupture and postinjury quadriceps strength would correlate well with quadriceps activation, allowing clinicians to use effusion and strength measurement as a surrogate for electrophysiological assessment of quadriceps activation. METHODS Prospective data were collected on 188 patients within 100 days of ACL injury (average, 27 days) referred from a single surgeon. A complete clinical evaluation of the knee was performed, including ligamentous assessment and assessment of range of motion and effusion. Quadriceps function was electrophysiologically assessed using maximal volitional isometric contraction and burst superimposition techniques to quantify both strength and activation. RESULTS Effusion grade did not correlate with quadriceps central activation ratio (CAR) (zero effusion: mean ± SD CAR, 93.5% ± 5.8%; trace effusion: CAR, 93.8% ± 9.5%; 1+ effusion: CAR, 94.0% ± 7.5%; 2+/3+ effusion: CAR, 90.6% ± 11.1%). These values are lower than normative data from healthy subjects (CAR, 98% ± 3%). CONCLUSION Joint effusion after ACL injury does not directly mediate quadriceps activation failure seen after injury. Therefore, it should not be used as a clinical substitute for electrophysiological assessment of quadriceps activation. Patients presenting to physical therapy after ACL injury should be treated with high-intensity neuromuscular electrical stimulation to help normalize this activation.

LYNCH, ANDREW D.; LOGERSTEDT, DAVID S.; AXE, MICHAEL J.; SNYDER-MACKLER, LYNN

2013-01-01

86

Lactate content and pH in muscle samples obtained after dynamic exercise  

Microsoft Academic Search

Analyzes were made on muscle samples taken from the lateral part of the m. quadriceps femoris of man (lactate, pyruvate, and pH) on venous blood (lactate, pyruvate) and on capillary blood (pH). Samples were taken at rest, immediately after termination of dynamic exercise and during 20 min recovery from exhaustive dynamic exercise.

K. Sahlin; R. C. Harris; B. Nylind; E. Hultman

1976-01-01

87

Intra- and interday reliability of voluntary and electrically stimulated isometric contractions of the quadriceps femoris.  

PubMed

The reliability of voluntary and electrically stimulated isometric contractions of m. quadriceps femoris of male participants (n=10; age 30±8years; height 1.79±0.05m; body mass 79.4±8.3kg) was investigated using ratio limits of agreement (LoA) on a time scale common to examine recovery from muscle damaging exercise. No systematic changes in reliability occurred over time (baseline versus 2, 24, 48, and 72h). Maximal voluntary contraction (MVC) and interpolated twitch technique (ITT) showed no mean bias (P>0.05) with 95% LoA of ±12.7 and ±5.4, respectively. Resting twitch and potentiated doublet peak force showed no mean bias (P>0.05). However, 95% LoA were smaller for the doublet (±13.9) than the twitch (±32.0). Twitch and doublet rates showed similar trends. Ratio of low (20Hz) to high (50Hz) frequency forces showed no mean bias (P>0.05) and 95% LoA of (±9.2). However, there was significant mean bias (P<0.05) and wider 95% LoA for peak force, contraction and relaxation parameters of the low and high frequency forces. In conclusion, MVC, ITT, potentiated doublet and the ratio of low to high frequency forces are recommended to most reliably examine functional muscle recovery between 2 and 72h after damaging exercise. PMID:23571022

Blacker, S D; Fallowfield, J L; Willems, M E T

2013-04-06

88

Quadriceps wasting and physical inactivity in patients with COPD.  

PubMed

Quadriceps weakness is an important complication of advanced chronic obstructive pulmonary disease (COPD) but few data exist concerning muscle bulk in early disease. We hypothesised that quadriceps bulk, measured by ultrasound rectus femoris cross-sectional area (USRF(CSA)), would be reduced in mild, as well as advanced, COPD compared with controls, and would correlate with physical activity. 161 patients with stable COPD and 40 healthy subjects had a measurement of USRF(CSA) and wore a multisensor armband to record physical activity. USRF(CSA) was reduced in Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I patients compared with healthy subjects (p=0.0002). Stage II-IV patients had reduced USRF(CSA) (p<0.0001) compared with controls but were not significantly different from those with stage I disease. Physical activity level was reduced in stage I (p=0.002) and stage II-IV disease compared with controls. Using regression analysis, physical activity level was independently associated with USRF(CSA) in stage I (p=0.01) but not stage II-IV disease, where residual volume to total lung capacity ratio was the only independent predictor of physical activity level. Quadriceps wasting exists in patients with mild, as well as advanced, COPD, and is independently associated with physical inactivity in GOLD stage I disease. The identification of these patients may guide early lifestyle and therapeutic interventions. PMID:22362854

Shrikrishna, Dinesh; Patel, Mehul; Tanner, Rebecca J; Seymour, John M; Connolly, Bronwen A; Puthucheary, Zudin A; Walsh, Simon L F; Bloch, Susannah A; Sidhu, Paul S; Hart, Nicholas; Kemp, Paul R; Moxham, John; Polkey, Michael I; Hopkinson, Nicholas S

2012-02-23

89

Quadriceps femoris muscle fatigue in patients with knee osteoarthritis  

PubMed Central

The purpose of this study was to characterize quadriceps femoris muscle fatigue of both lower extremities in patients with knee osteoarthritis (OA). Sixty-two subjects (mean age 68.2 years, standard deviation [SD] ± 7.9 years) with knee OA participated in the study. Significantly higher knee pain was reported in the involved knee than in the contralateral knee, as determined by a visual analog scale. Significant differences were demonstrated between the lower extremities in terms of maximal voluntary isometric contraction, in favor of the less involved leg (P = 0.0001). In contrast, the degree of fatigue of the quadriceps femoris muscle, as measured by the decrement in force production following ten repeated contractions, was significantly higher in the contralateral leg (P = 0.0002). Furthermore, normalization of the fatigue results to the first contraction yielded a similar result (P < 0.0001). Similar results were noted when analysis was performed separately for subjects whose involvement was unilateral or bilateral. The results indicate that, irrespective of the initial strength of contraction, the rate of muscle fatigue in the contralateral leg is significantly higher than in the involved leg. Hypotheses for these unexpected results are suggested. Rehabilitation of patients with knee OA should focus on increasing quadriceps muscle strength and endurance for both lower extremities.

Elboim-Gabyzon, M; Rozen, N; Laufer, Y

2013-01-01

90

Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans.  

PubMed

We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to approximately 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly (P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly (P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow. PMID:20507965

Athanasopoulos, Dimitris; Louvaris, Zafeiris; Cherouveim, Evgenia; Andrianopoulos, Vasilis; Roussos, Charis; Zakynthinos, Spyros; Vogiatzis, Ioannis

2010-05-27

91

Effect of Knee Position on Quadriceps Muscle Force Steadiness and Activation Strategies  

PubMed Central

Introduction This study investigated the effect of knee position on quadriceps force steadiness and activation strategies. Methods Quadriceps force steadiness was evaluated in twenty-two volunteers at two knee positions by testing their ability to regulate submaximal force. Muscle activation strategies were studied in both time and frequency domains using surface electromyography. Results Quadriceps force fluctuations and the associated agonist and antagonist activity were significantly higher at 90° than at 30° of flexion (P < 0.05). The quadriceps median frequency recorded at 30° was significantly higher than at 90° of flexion (P < 0.05). Regression analyses revealed that force steadiness was related to quadriceps activation and median frequency (P < 0.001), but not to hamstring coactivation (P > 0.05). Discussion The results indicate that knee position significantly affects quadriceps force steadiness and activation strategies. This finding may have important implications for designing a force control testing protocol and interpreting test results.

Krishnan, Chandramouli; Allen, Eric J.; Williams, Glenn N.

2010-01-01

92

Creatine Loading, Resistance Exercise Performance, and Muscle Mechanics.  

ERIC Educational Resources Information Center

Examined whether creatine (CR) monohydrate loading would alter resistance exercise performance, isometric strength, or in vivo contractile properties of the quadriceps femoris muscle compared with placebo loading in resistance-trained athletes. Overall, CR loading did not provide an ergogenic benefit for the unilateral dynamic knee extension…

Stevenson, Scott W.; Dudley, Gary A.

2001-01-01

93

Creatine Loading, Resistance Exercise Performance, and Muscle Mechanics.  

ERIC Educational Resources Information Center

|Examined whether creatine (CR) monohydrate loading would alter resistance exercise performance, isometric strength, or in vivo contractile properties of the quadriceps femoris muscle compared with placebo loading in resistance-trained athletes. Overall, CR loading did not provide an ergogenic benefit for the unilateral dynamic knee extension…

Stevenson, Scott W.; Dudley, Gary A.

2001-01-01

94

Restoration of quadriceps femoris function with a dynamic microsurgical free latissimus dorsi muscle transfer.  

PubMed

Loss of knee extension caused by quadriceps femoris muscle disruption can be a disabling injury. Attempts at reconstructing the large muscle deficit after oncological resections of the quadriceps have previously had some success using a dynamic free latissimus dorsi muscle transfer. This concept proved to be similarly valuable after a gunshot wound to the thigh resulted in an isolated loss of the quadriceps mechanism. A reinnervated latissimus dorsi muscle bridging the quadriceps muscle gap proved to have active contraction and permitted full active knee extension, demonstrating the value of this muscle also for restoration of function after traumatic injuries. PMID:14676706

Hallock, Geoffrey G

2004-01-01

95

Simultaneous rupture of bilateral quadriceps tendon and rotator cuff tear: a case report.  

PubMed

This is a case report of a patient who sustained both a bilateral quadriceps tendon rupture and a complete rotator cuff tear. Overuse is a known risk factor for rotator cuff tears, but this case suggests that it can also be a risk factor for quadriceps tendon rupture. PMID:23155972

Chen, H T

2012-03-01

96

An evaluation of the relationship between vitamin d status and quadriceps strength in patients with copd: a cross sectional study  

Microsoft Academic Search

BackgroundQuadriceps muscle weakness is a well-defined characteristic of chronic obstructive pulmonary disease (COPD). Vitamin D deficiency has been shown to be highly prevalent in COPD but its association with quadriceps strength in this group is unknown.ObjectivesTo investigate the effects of Vitamin D status on quadriceps strength. To validate measurements of quadriceps strength by handheld dynamometer (HHD) against the gold standard

J Fenn; A Martineau; J Wai Yee; K Islam; C Griffiths; N Maffulli; D Morrissey

2011-01-01

97

Patellar eversion does not adversely affect quadriceps recovery following total knee arthroplasty.  

PubMed

Although avoiding patellar eversion during a total knee arthroplasty (TKA) has theoretical benefit in quadriceps recovery, there has been paucity of supportive objective clinical results. We prospectively designed the study whether TKA without patellar eversion has better quadriceps recovery in an objective, dynamometer study. Seventy-two knees undergoing TKA with midvastus approach were randomized into two groups according to patellar eversion or not. Clinical data and objective quadriceps recovery using a dynamometer were investigated preoperatively and postoperative at 6weeks, 3months, 6months and 1year. There were no statistical differences between two groups throughout the follow-up periods in recovery of quadriceps force or power and clinical data. Choosing to evert patella during TKA using midvastus approach would not adversely affect postoperative quadriceps recovery. PMID:23153598

Umrani, Salil P; Cho, Kye-Youl; Kim, Kang-Il

2012-11-12

98

Muscle blood flow and flow heterogeneity during exercise studied with positron emission tomography in humans  

Microsoft Academic Search

Blood flow is the main regulator of skeletal muscle's oxygen supply, and several studies have shown heterogeneous blood flow\\u000a among and within muscles. However, it remains unclear whether exercise changes the heterogeneity of flow in exercising human\\u000a skeletal muscle. Muscle blood flow and spatial flow heterogeneity were measured simultaneously in exercising and in the contralateral\\u000a resting quadriceps femoris (QF) muscle

Kari K. Kalliokoski; Jukka Kemppainen; Kirsti Larmola; Teemu O. Takala; Pauliina Peltoniemi; Airi Oksanen; Ulla Ruotsalainen; Claudio Cobelli; Juhani Knuuti; Pirjo Nuutila

2000-01-01

99

Post-exercise alcohol ingestion exacerbates eccentric-exercise induced losses in performance.  

PubMed

The effect of acute alcohol intake on muscular performance in both the exercising and non-exercising legs in the days following strenuous eccentric exercise was investigated to ascertain whether an interaction between post-exercise alcohol use and muscle damage causes an increase in damage-related weakness. Ten healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed either a beverage containing 1 g of ethanol per kg bodyweight ethanol (as vodka and orange juice; ALC) or a non-alcoholic beverage (OJ). At least 2 weeks later they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed the other beverage. Measurement of peak and average peak isokinetic (concentric and eccentric) and isometric torque produced by the quadriceps of both exercising and non-exercising legs was made before and 36 and 60 h post-exercise. Greatest decreases in exercising leg performance were observed at 36 h with losses of 28.7, 31.9 and 25.9% occurring for OJ average peak isometric, concentric, and eccentric torques, respectively. However, average peak torque loss was significantly greater in ALC with the same performance measures decreasing by 40.9, 42.8 and 44.8% (all p < 0.05). Performance of the non-exercising leg did not change significantly under either treatment. Therefore, consumption of moderate amounts of alcohol after damaging exercise magnifies the loss of force associated with strenuous eccentric exercise. This weakness appears to be due to an interaction between muscle damage and alcohol rather than the systemic effects of acute alcohol consumption. PMID:20012446

Barnes, Matthew J; Mündel, Toby; Stannard, Stephen R

2009-12-11

100

A randomised clinical trial of the efficacy of drop squats or leg extension/leg curl exercises to treat clinically diagnosed jumper's knee in athletes: pilot study  

PubMed Central

Objectives—To compare the therapeutic effect of two different exercise protocols in athletes with jumper's knee. Methods—Randomised clinical trial comparing a 12 week programme of either drop squat exercises or leg extension/leg curl exercises. Measurement was performed at baseline and after six and 12 weeks. Primary outcome measures were pain (visual analogue scale 1–10) and return to sport. Secondary outcome measures included quadriceps and hamstring moment of force using a Cybex II isokinetic dynamometer at 30°/second. Differences in pain response between the drop squat and leg extension/curl treatment groups were assessed by 2 (group) x 3 (time) analysis of variance. Two by two contingency tables were used to test differences in rates of return to sport. Analysis of variance (2 (injured versus non-injured leg) x 2 (group) x 3 (time)) was also used to determine differences for secondary outcome measures. Results—Over the 12 week intervention, pain diminished by 2.3 points (36%) in the leg extension/curl group and 3.2 points (57%) in the squat group. There was a significant main effect of both exercise protocols on pain (p<0.01) with no interaction effect. Nine of 10 subjects in the drop squat group returned to sporting activity by 12 weeks, but five of those subjects still had low level pain. Six of nine of the leg extension/curl group returned to sporting activity by 12 weeks and four patients had low level pain. There was no significant difference between groups in numbers returning to sporting activity. There were no differences in the change in quadriceps or hamstring muscle moment of force between groups. Conclusions—Progressive drop squats and leg extension/curl exercises can reduce the pain of jumper's knee in a 12 week period and permit a high proportion of patients to return to sport. Not all patients, however, return to sport by that time. Key Words: knee; patellar tendon; tendinopathy; tendinosis; eccentric strengthening; strength training

Cannell, L; Taunton, J; Clement, D; Smith, C; Khan, K

2001-01-01

101

Emergency department diagnosis of a quadriceps intramuscular loculated abscess/pyomyositis using dynamic compression bedside ultrasonography  

PubMed Central

Introduction A 73-year-old man with a past medical history of myelodysplastic syndrome and recent chemotherapy presented to the emergency department with a 1-week history of progressively increasing left thigh pain and swelling. His physical examination revealed left anterolateral diffuse thigh swelling with no erythema or warmth to palpation. The anterolateral quadriceps was markedly tender to palpation. Emergency department bedside dynamic compression ultrasonography that was performed on the left anterolateral thigh revealed a quadriceps intramuscular abscess with loculated yet movable pus. Conclusion Bedside dynamic compression ultrasonography can assist the emergency or critical care physician in the diagnosis of quadriceps intramuscular abscess or pyomyositis.

2013-01-01

102

Influence of resistance and aerobic exercise on hunger, circulating levels of acylated ghrelin, and peptide YY in healthy males  

Microsoft Academic Search

ABSTRACT Resistance (muscle strengthening) exercise is a ,key component ,of exercise ,recommendations ,for weight,control yet very little is known ,about the effects of resistance ,exercise on appetite. We

David R Broom; Rachel L Batterham; James A King; David J Stensel

2008-01-01

103

Preferential quadriceps activation in female athletes with incremental increases in landing intensity.  

PubMed

The purpose of this study was to identify alterations in preparatory muscle activation patterns across different drop heights in female athletes. Sixteen female high school volleyball players performed the drop vertical jump from three different drop heights. Surface electromyography of the quadriceps and hamstrings were collected during the movement trials. As the drop height increased, muscle activation of the quadriceps during preparatory phase also increased (p < .05). However, the hamstrings activation showed no similar increases relative to drop height. Female athletes appear to preferentially rely on increased quadriceps activation, without an increase in hamstrings activation, with increased plyometric intensity. The resultant decreased activation ratio of the hamstrings relative to quadriceps before landing may represent altered dynamic knee stability and may contribute to the increased risk of ACL injury in female athletes. PMID:21844610

Ford, Kevin R; Myer, Gregory D; Schmitt, Laura C; Uhl, Timothy L; Hewett, Timothy E

2011-08-01

104

Exercise intention, age and stress predict increased qigong exercise adherence.  

PubMed

Adherence to exercise is paramount if desired health effects are to be achieved. Drop-out rates in excess of 50% have been reported, with the intensity of the exercise performed frequently blamed. Qigong is a low-intensity mind-body technique that may offer an alternative to more intense modes of exercise. The aim of this study was therefore, to determine if exercise motives, exercise intention, age, stress and energy levels predict adherence to qigong exercise. Participants (n=87) were assessed by self-rated retrospective physical activity behavior, by performed qigong exercise and concentration level, and by sport motivation scale, planned behavior questionnaire, and stress and energy scale. Exercise intention, age and stress predicted exercise frequency (R(2)=.29); when level of concentration (a non-baseline assessment) was included as a predictor, prediction strength increased (R(2)=.38). Results suggest that health-professionals who are aiming to secure activity adherence and exercise frequency, should focus on strengthening the individual's intention to exercise, promoting a calm energy state before commencement of exercise, and encouraging a heightened level of concentration during exercise. PMID:19329057

Jouper, John; Hassmén, Peter

2008-12-03

105

Creatine kinase, myosin heavy chains and magnetic resonance imaging after eccentric exercise  

Microsoft Academic Search

The aim of this study was to examine the relationship between myosin heavy chain (MHC) release as a specific marker of slow-twitch muscle fibre breakdown and magnetic resonance imaging (MRI) of skeletal muscle injury after eccentric exercise. The effects of a single series of 70 high-intensity eccentric contractions of the quadriceps femoris muscle group (single leg) on plasma concentrations of

Stephan Sorichter; Johannes Mair; Arnold Koller; Erich Muller; Christian Kremser; Werner Judmaier; Christian Haid; Charles Calzolari; Bernd Puschendorf

2001-01-01

106

Development of an indoor rowing machine with manual FES controller for total body exercise in paraplegia  

Microsoft Academic Search

Concept 2 indoor rowing machine (Concept 2 Inc., USA) was modified for functional electrical stimulation (FES) rowing exercise in paraplegia. A new seating system provides trunk stability and constrains the leg motion to the sagittal plane. A 4-channel electrical stimulator activates the quadriceps and hamstrings in Drive and Recovery phases of the rowing cycle, respectively. Two force-sensing resistors (FSR) on

Rahman Davoodi; Brian J. Andrews; Garry D. Wheeler; Robert Lederer

2002-01-01

107

Unilateral Lower Limb Injury: Its Long-Term Effects on Quadriceps, Hamstring, and Plantarflexor Muscle Strength  

Microsoft Academic Search

Holder-Powell HM, Rutherford OM. Unilat- eral lower limb injury: its long-term effects on quadriceps, hamstring, and plantarflexor muscle strength. Arch Phys Med Rehabil 1999;80:717-720. Objective: To ascertain if long-term deficits in quadriceps, hamstring, and plantarflexor muscle strength remain after unilateral lower-limb musculoskeletal injury and to quantify whether improvements in performance continue once a subject concludes rehabilitation and returns to everyday

Heather M. Holder-Powell; Olga M. Rutherford

108

Differences in quadriceps muscle strength and fatigue between lean and obese subjects  

Microsoft Academic Search

The present study aimed to compare quadriceps femoris muscle strength and fatigue between obese (grade II and III) and nonobese\\u000a adults. Ten obese (mean age: 25 years; mean BMI: 41 kg\\/m²) and ten lean (mean age: 27 years; mean BMI: 23 kg\\/m²) men were\\u000a tested. Quadriceps muscle fatigue was quantified as the (percent) torque loss during a voluntary isokinetic (50 maximal contractions\\u000a at 180°\\/s)

Nicola A. Maffiuletti; Marc Jubeau; Urs Munzinger; Mario Bizzini; Fiorenza Agosti; Alessandra De Col; Claudio L. Lafortuna; Alessandro Sartorio

2007-01-01

109

Simultaneous Bilateral Quadriceps Tendon Rupture in a Patient with Chronic Renal Failure  

PubMed Central

Bilateral quadriceps tendon rupture is an unusual injury, but may be encountered in patients with various chronic diseases after minor trauma. This article presents a case of bilateral quadriceps tendon rupture of a 38-year-old woman with chronic renal failure. Surgical repair was performed using a bone tunnel technique with a nonabsorbable suture and a suture anchor. Postoperative magnetic resonance imaging confirmed complete healing of the repair site, and clinically active extension with 120 degrees of range of motion was achieved.

Kim, Byung Soo; Kim, Yong Wook; Song, Eun Kyoo; Kang, Kyung Do; Kim, Hyung Nam

2012-01-01

110

Strength and physiological response to exercise in patients with chronic fatigue syndrome  

PubMed Central

OBJECTIVE—To measure strength, aerobic exercise capacity and efficiency, and functional incapacity in patients with chronic fatigue syndrome (CFS) who do not have a current psychiatric disorder.?METHODS—Sixty six patients with CFS without a current psychiatric disorder, 30 healthy but sedentary controls, and 15 patients with a current major depressive disorder were recruited into the study. Exercise capacity and efficiency were assessed by monitoring peak and submaximal oxygen uptake, heart rate, blood lactate, duration of exercise, and perceived exertion during a treadmill walking test. Strength was measured using twitch interpolated voluntary isometric quadriceps contractions. Symptomatic measures included physical and mental fatigue, mood, sleep, somatic amplification, and functional incapacity.?RESULTS—Compared with sedentary controls, patients with CFS were physically weaker, had a significantly reduced exercise capacity, and perceived greater effort during exercise, but were equally unfit. Compared with depressed controls, patients with CFS had significantly higher submaximal oxygen uptakes during exercise, were weaker, and perceived greater physical fatigue and incapacity. Multiple regression models suggested that exercise incapacity in CFS was related to quadriceps muscle weakness, increased cardiovascular response to exercise, and body mass index. The best model of the increased exercise capacity found after graded exercise therapy consisted of a reduction in submaximal heart rate response to exercise.?CONCLUSIONS—Patients with CFS were weaker than sedentary and depressed controls and as unfit as sedentary controls. Low exercise capacity in patients with CFS was related to quadriceps muscle weakness, low physical fitness, and a high body mass ratio. Improved physical fitness after treatment was associated with increased exercise capacity. These data imply that physical deconditioning helps to maintain physical disability in CFS and that a treatment designed to reverse deconditioning helps to improve physical function.??

Fulcher, K.; White, P.

2000-01-01

111

The effect of beta-blockade on plasma potassium concentrations and muscle excitability following static exercise  

Microsoft Academic Search

The effects of ?-blockade on plasma [K+], muscle excitability and force during fatiguing exercise were examined. Nine healthy males (mean age 22.3±1.7 yr) performed\\u000a a 3-min fatigue protocol that consisted of a sustained submaximal contraction (30% of the maximal voluntary contraction, MVC)\\u000a of the right quadriceps muscle. Subjects performed the exercise after treatment with either placebo, ?1-selective (metoprolol, 100 mg) or an

Karen Unsworth; A. Hicks; Robert McKelvie

1998-01-01

112

Altered mitochondrial regulation in quadriceps muscles of patients with COPD.  

PubMed

Evidence exists for locomotor muscle impairment in patients with chronic obstructive pulmonary disease (COPD), including fiber type alterations and reduced mitochondrial oxidative capacity. In this study high-resolution respirometry was used to quantify oxygen flux in permeabilized fibres from biopsies of the vastus lateralis muscle in patients with COPD and compared to healthy control subjects. The main findings of this study were that (i) routine state 2 respiration was higher in COPD; (ii) state 3 respiration in the presence of ADP was similar in both groups with substrate supply of electrons to complex I (COPD 38·28 ± 3·58 versus control 42·85 ± 3·10 pmol s(-1) mg tissue(-1) ), but O(2) flux with addition of succinate was lower in COPD patients (COPD 63·72 ± 6·33 versus control 95·73 ± 6·53 pmol s(-1) mg tissue(-1) ); (iii) excess capacity of cytochrome c oxidase in COPD patients was only ~50% that of control subjects. These results indicate that quadriceps muscle mitochondrial function is altered in patients with COPD. The regulatory mechanisms underlying these functional abnormalities remain to be uncovered. PMID:21091605

Naimi, Ashley I; Bourbeau, Jean; Perrault, Helene; Baril, Jacinthe; Wright-Paradis, Cynthia; Rossi, Amanda; Taivassalo, Tanja; Sheel, A William; Rabøl, Rasmus; Dela, Flemming; Boushel, Robert

2010-11-22

113

Exercise behaviors after burn injury.  

PubMed

The purpose of this study was to investigate exercise behaviors in adult burn survivors and to identify barriers to exercise in this population. A two-page questionnaire developed by the authors was administered on a single occasion to adults attending the ambulatory burns clinic at a metropolitan hospital. Data from 68 adult burn survivors were analyzed. Within this cohort, 59% of subjects reported exercising several times per week or more and the remaining 41% exercised once per week or less. There was no correlation among exercise frequency and age, TBSA, or hospital length of stay. Walking was the most common type of exercise, and subjects reported lower compliance with stretching and strengthening exercises. Physical condition and motivation were identified as the main barriers to exercise. Although this preliminary study reveals that a higher proportion of burn survivors engage in exercise compared with their healthy counterparts, a substantial number are exercising just once per week or less, below the recommended guidelines to improve physical fitness. Physical and occupational therapists play an important role in providing exercise prescription and education, as well as addressing barriers to exercise in burn survivors. The potential for further research into physical activity across all domains of life using a validated questionnaire is identified. PMID:23816997

Baldwin, Jennifer; Li, Frank

114

Biomechanics of front and back squat exercises  

Microsoft Academic Search

Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee.

A A Braidot; M H Brusa; F E Lestussi; G P Parera

2007-01-01

115

Effects of Directional Exercise on Lingual Strength  

ERIC Educational Resources Information Center

|Purpose: To examine the application of known muscle training principles to tongue strengthening exercises and to answer the following research questions: (a) Did lingual strength increase following 9 weeks of training? (b) Did training conducted using an exercise moving the tongue in one direction result in strength changes for tongue movements…

Clark, Heather M.; O'Brien, Katy; Calleja, Aimee; Corrie, Sarah Newcomb

2009-01-01

116

Peripheral muscle endurance and the oxidative profile of the quadriceps in patients with COPD  

PubMed Central

Background: Based on previously reported changes in muscle metabolism that could increase susceptibility to fatigue, we speculated that patients with chronic obstructive pulmonary disease (COPD) have reduced quadriceps endurance and that this will be correlated with the proportion of type I muscle fibres and with the activity of oxidative enzymes. Methods: The endurance of the quadriceps was evaluated during an isometric contraction in 29 patients with COPD (mean (SE) age 65 (1) years; forced expiratory volume in 1 second 37 (3)% predicted) and 18 healthy subjects of similar age. The electrical activity of the quadriceps was recorded during muscle contraction as an objective index of fatigue. The time at which the isometric contraction at 60% of maximal voluntary capacity could no longer be sustained was used to define time to fatigue (TF). Needle biopsies of the quadriceps were performed in 16 subjects in both groups to evaluate possible relationships between TF and markers of muscle oxidative metabolism (type I fibre proportion and citrate synthase activity). Results: TF was lower in patients with COPD than in controls (42 (3) v 80 (7) seconds; mean difference 38 seconds (95% CI 25 to 50), p<0.001). Subjects in both groups had evidence of electrical muscle fatigue at the end of the endurance test. In both groups significant correlations were found between TF and the proportion of type I fibres and citrate synthase activity. Conclusion: Isometric endurance of the quadriceps muscle is reduced in patients with COPD and the muscle oxidative profile is significantly correlated with muscle endurance.

Allaire, J; Maltais, F; Doyon, J; Noel, M; LeBlanc, P; Carrier, G; Simard, C; Jobin, J

2004-01-01

117

Maximum oxygen uptake corrected for skeletal muscle mass accurately predicts functional improvements following exercise training in chronic heart failure  

Microsoft Academic Search

Background: Skeletalmusclemassandpeakoxygenuptakeareimportantpredictorsoffunctionalstatusandoutcomeinpatientswithstable chronic heart failure. Aims: To assess changes in skeletal muscle mass and peak oxygen uptake following an exercise training program. Methods: Thirty-six patients with moderate stable chronic heart failure were randomly allocated to either a bicycle ergometer (bike) or functional electrical muscle stimulators (FES) applied to quadriceps and gastrocnemius muscles to be used daily for six weeks. Dual-energy

John P. LeMaitre; Stuart Harris; Jim Hannan; Keith A. A. Fox; Martin A. Denvir

2006-01-01

118

Changes in ventilation related to changes in electromyograph activity during repetitive bouts of isometric exercise in simulated sailing  

Microsoft Academic Search

This study examined the control of ventilation during repetitive bouts of isometric exercise in simulated sailing. Eight male sailors completed four successive 3-min bouts of similar isometric effort on a dinghy simulator, bouts were separated by 15-s rest intervals. Quadriceps muscle integrated electromyograph activity (iEMG) was recorded during each bout and expressed as a percentage of activity during maximal voluntary

I. Vogiatzis; N. C. Spurway; S. Jennett; J. Wilson; J. Sinclair

1996-01-01

119

The time-course of voluntary and electrically evoked muscle performance during and after stretch-shortening exercise is different  

Microsoft Academic Search

The aim of the study was to establish the dynamics of maximal voluntary contraction force (MVCF), height of drop jump (DJ) and electrically evoked quadriceps muscle force at different stimulation frequencies during and after 100 DJs (stretch- shortening exercise, SSE). Healthy untrained men (n = 11; age = 21.8 ± 1.7 years) participated in the study. DJs were performed with

Albertas Skurvydas; Gediminas Mamkus; Dalia Mickeviciene; Nerijus Masiulis; Vytautas Streckis

2007-01-01

120

Medial Quadriceps Tendon-Femoral Ligament: Surgical Anatomy and Reconstruction Technique to Prevent Patella Instability  

PubMed Central

Detailed anatomic dissections of the deep medial knee retinaculum have shown a consistent prominent anatomic structure extending from the distal deep quadriceps tendon to the adductor tubercle region, forming a distinct medial quadriceps tendon–femoral ligament (MQTFL). Reconstruction of this anatomic structure has yielded consistent medial stabilization of the patellofemoral joint without drilling into the patella over more than 3 years in patients with recurrent patella instability and dislocation. Results are similar to those of MPFL reconstruction but with reduced risk of patella fracture, a known and serious complication of MPFL reconstruction. The reconstruction graft is secured at the anatomic femoral origin of the MQTFL and brought under the vastus medialis such that it may be woven and attached to the deep distal medial quadriceps tendon to provide a secure, reliable reproduction of the MQTFL and excellent stabilization of the patellofemoral joint without risk of patella fracture.

Fulkerson, John P.; Edgar, Cory

2013-01-01

121

Reconstruction of quadriceps tendon with Achilles tendon allograft in older children with congenital dislocation of the knee  

Microsoft Academic Search

This is a case report of two children with congenital dislocation of the knee. They have been treated surgically with Z-lengthening of the quadriceps tendon and additional reconstruction of the quadriceps tendon with Achilles tendon allograft to fill in the remaining average 6 cm gap of the tendon. The patients were two girls, 6 and 9 years old. One of them had

Yetkin Söyüncü; Ercan M?hç?; Haluk Özcanl?; Merter Özenci; Feyyaz Aky?ld?z; A. Turan Ayd?n

2006-01-01

122

Bilateral simultaneous rupture of the quadriceps tendon in an adult amateur tennis player.  

PubMed

Bilateral simultaneous quadriceps tendon rupture is a relatively rare injury, requiring prompt diagnosis and surgical repair. It is more common in patients older than 50 years and is usually associated with underlying metabolic or inflammatory diseases. Its occurrence is very rare in healthy individuals. We report a case of bilateral quadriceps tendon rupture in a healthy young adult that occurred while he was playing tennis. This patient presented with acute knee swellings, total inability to extend the legs, and a palpable gap above the patella. PMID:16484878

Katz, Tiberin; Alkalay, Daphna; Rath, Ehud; Atar, Dan; Sukenik, Shaul

2006-02-01

123

Dynamic electromyography after cruciate-retaining total knee arthroplasty revealed a threefold quadriceps demand compared with the contralateral normal knee.  

PubMed

Quadriceps functional impairment accounts for a considerable amount of morbidity after knee replacement. Cruciate-retaining total knee arthroplasty (CR-TKA) may predispose to increased quadriceps demand. We compared bilateral relative quadriceps effort in seven patients with successful unilateral CR-TKA at least 2years after surgery. Dynamic electromyography (EMG) recorded quadriceps activity during walking recorded simultaneously with gait analysis using IDEEA. There was greater EMG activity for the operated knees, both in amplitude (43.08±26.47 vs. 16.02±5.38, P=.0355), and the area under the curve (7231.1±3869.8 vs. 2547.3±1007.9, P=.0267). The onset and duration of muscle activity were similar for both knees (P=.74). CR-TKA demonstrated threefold EMG activity and muscle effort during normal walking. The study suggested that quadriceps functional deficiency is associated with CR-TKA. PMID:23265273

Lester, D Kevin; Shantharam, Rohini; Zhang, Kuan

2012-12-21

124

Effects of isometric strength training on quadriceps muscle properties in over 55 year olds  

Microsoft Academic Search

Changes in strength, speed and size of the quadriceps muscle have been investigated in elderly men and women after 6 months of isometric strength training. We have also indirectly investigated the role of metabolites as a stimulus for muscle hypertrophy by studying two training protocols. One thigh was trained using short, intermittent contractions (IC), while the other trained using long,

L. Welsh; O. M. Rutherford

1996-01-01

125

Intra- and intermuscular variation in human quadriceps femoris architecture assessed in vivo  

Microsoft Academic Search

Despite the functional importance of the human quadriceps femoris in movements such as running, jumping, lifting and climbing, and the known effects of muscle architecture on muscle function, no research has fully described the complex architecture of this muscle group. We used ultrasound imaging techniques to measure muscle thickness, fascicle angle and fascicle length at multiple regions of the four

Anthony J. Blazevich; Nicholas David Gill; Shi Zhou

2006-01-01

126

Contraction characteristics of the human quadriceps muscle during percutaneous electrical stimulation  

Microsoft Academic Search

Percutaneous electrical stimulation was used to study the force response of the quadriceps muscle. The normal frequency dependence of force was investigated in muscles at rest and after fatiguing contractions. A comparison between force response during fatigue induced by electrical stimulation at different frequencies and by voluntary work suggested equal changes in contractility, irrespective of the fatigue-inducing procedure. In fresh

M. Bergstriim; E. Hultman

1990-01-01

127

Morphometric analyses of normal pediatric brachial biceps and quadriceps muscle tissue  

PubMed Central

Summary Pediatric normal brachial biceps (14 specimens) and quadriceps muscles (14 specimens) were studied by immunohistochemistry to quantify fiber-type, diameter and distribution, capillary density, presence of inflammatory cells (CD3, CD20, CD68) and expression of neonatal myosin and MHC class 1 proteins. Brachial biceps showed more fast-twitch fibers and lower capillary/fiber ratio than quadriceps. The mean diameter of both fiber types was smaller in biceps than quadriceps. Fast-fibers were smaller than slow-fibers, and capillary/fiber ratio was <1.0 in both muscles. Fiber size and capillary/fiber ratio increased with age. Normal limits for infiltrating haematopoietic cells were <4 T lymphocytes, or CD68+ cells, very few B cells, <6 neonatal myosin positive fibers, and no fibers MHC class 1 positive in one ×20 field, for both muscles. The present comparison of quantitative findings between brachial biceps and quadriceps may allow standardization of the assessment of pathological changes in both pediatric muscles.

Sallum, Adriana M.E.; Varsani, Hemlata; Holton, Janice L.; Marie, Suely K.N.; Wedderburn, Lucy R.

2013-01-01

128

Eccentric and concentric torque-velocity characteristics of the quadriceps femoris in man  

Microsoft Academic Search

Summary  The primary purpose of this investigation was to study the eccentric and concentric torque-velocity characteristics of the quadriceps femoris in man using a recently developed combined isometric, concentric and eccentric controlled velocity dynamometer (the SPARK System). A secondary purpose was to compare the method error associated with maximal voluntary concentric and eccentric torque output over a range of testing velocities.

Stephen H. Westing; Jan Y. Seger; Eddy Karlson; Björn Ekblom

1988-01-01

129

Fatigue effects on quadriceps and hamstrings activation in dancers performing drop landings.  

PubMed

Fatigue may reduce a dancer's ability to maintain the muscle synergies required for stable human movement. Therefore, fatigue presents as a potential risk factor for injury in dancers. Activation patterns of the quadriceps and hamstrings muscle groups in athletic populations have been consistently reported to alter in response to fatigue during landing tasks. It is unknown whether dancers demonstrate similar muscle activation patterns, nor if dancers respond to fatiguing protocols, with regard to muscle activation, in the same manner as their athletic counter-parts. The purpose of this study was to assess quadriceps and hamstrings activation levels in a cohort of dancers performing drop landings before and after completion of a dance-specific fatigue protocol, the High Intensity Dance Performance Fitness Test. Quadriceps and hamstrings co-contraction ratios significantly increased between pre- and post-fatigue conditions in a similar fashion to that reported in the literature. Therefore, the neuromuscular activation of the knee extensors and flexors in dancers changed in response to the dance-specific fatiguing protocol. Furthermore, quadriceps and hamstrings co-contraction ratios were substantially greater than previously reported in other athletic populations, due to low hamstrings activation levels. Future investigation of dancer biomechanical adaptations to fatigue would be beneficial to further examine the potential implications for injury risk. PMID:24069945

McEldowney, Kasey M; Hopper, Luke S; Etlin-Stein, Hannah; Redding, Emma

2013-01-01

130

Bilateral rectus femoris intramuscular haematoma following simultaneous quadriceps strain in an athlete: a case report  

Microsoft Academic Search

INTRODUCTION: Bilateral rectus femoris haematoma following a simultaneous strain of the quadriceps muscles is a very rare condition. CASE PRESENTATION: We report the case of a 21-year-old Greek Caucasian female rowing athlete who was injured on both thighs. She complained of pain and inability to walk. Physical examination revealed tenderness over the thighs and restriction of knee movement. The result

Konstantinos Natsis; Christos Lyrtzis; Georgios Noussios; Efthymia Papathanasiou; Nikolaos Anastasopoulos; Trifon Totlis

2010-01-01

131

Morphometric analyses of normal pediatric brachial biceps and quadriceps muscle tissue.  

PubMed

Pediatric normal brachial biceps (14 specimens) and quadriceps muscles (14 specimens) were studied by immunohistochemistry to quantify fiber-type, diameter and distribution, capillary density, presence of inflammatory cells (CD3, CD20, CD68) and expression of neonatal myosin and MHC class 1 proteins. Brachial biceps showed more fast-twitch fibers and lower capillary/fiber ratio than quadriceps. The mean diameter of both fiber types was smaller in biceps than quadriceps. Fast-fibers were smaller than slow-fibers, and capillary/fiber ratio was < 1.0 in both muscles. Fiber size and capillary / fiber ratio increased with age. Normal limits for infiltrating haematopoietic cells were <4 T lymphocytes, or CD68+ cells, very few B cells, < 6 neonatal myosin positive fibers, and no fibers MHC class 1 positive in one x20 field, for both muscles. The present comparison of quantitative findings between brachial biceps and quadriceps may allow standardization of the assessment of pathological changes in both pediatric muscles. PMID:23392619

Sallum, Adriana M E; Varsani, Hemlata; Holton, Janice L; Marie, Suely K N; Wedderburn, Lucy R

2013-02-08

132

Core Exercises: Why You Should Strengthen Your Core Muscles  

MedlinePLUS

... and don'ts of proper technique see all in Strength training Sports nutrition (3) Performance-enhancing drugs: Know the risks ... on the playing field or in daily activities. In fact, most sports and other physical activities depend on stable core ...

133

Quadriceps oxygenation changes during walking and running on a treadmill  

NASA Astrophysics Data System (ADS)

Vastus lateralis muscle oxygenation was investigated on volunteers as well as muscular dystrophy patients during a walking test, and on volunteers during a free running by a continuous wave near infrared instrument. The data were analyzed using an oxygenation index independent on pathlength changes. Walking did not significantly affect the oxygenation of volunteers and patients. A relative deoxygenation was found only during free running indicating an unbalance between oxygen supply and tissue oxygen extraction. Preliminary measurements of exercising muscle oxygen saturation were performed by a 110 MHz frequency-domain, multisource instrument.

Quaresima, Valentina; Pizzi, Assunta; de Blasi, Roberto A.; Ferrari, Adriano; de Angelis, Marco; Ferrari, Marco

1995-04-01

134

Exercise Prescription.  

ERIC Educational Resources Information Center

|If exercise programs are to become effective in producing the desired results, then the correct exercise prescription must be applied. Four variables should be controlled in the prescription of exercise: (a) type of activity, (b) intensity, (c) duration, and (d) frequency. The long-term prescription of exercise involves the use of a (a) starter…

Ribisl, Paul M.

135

Abdominal muscle fatigue following exercise in chronic obstructive pulmonary disease  

PubMed Central

Background In patients with chronic obstructive pulmonary disease, a restriction on maximum ventilatory capacity contributes to exercise limitation. It has been demonstrated that the diaphragm in COPD is relatively protected from fatigue during exercise. Because of expiratory flow limitation the abdominal muscles are activated early during exercise in COPD. This adds significantly to the work of breathing and may therefore contribute to exercise limitation. In healthy subjects, prior expiratory muscle fatigue has been shown itself to contribute to the development of quadriceps fatigue. It is not known whether fatigue of the abdominal muscles occurs during exercise in COPD. Methods Twitch gastric pressure (TwT10Pga), elicited by magnetic stimulation over the 10th thoracic vertebra and twitch transdiaphragmatic pressure (TwPdi), elicited by bilateral anterolateral magnetic phrenic nerve stimulation were measured before and after symptom-limited, incremental cycle ergometry in patients with COPD. Results Twenty-three COPD patients, with a mean (SD) FEV1 40.8(23.1)% predicted, achieved a mean peak workload of 53.5(15.9) W. Following exercise, TwT10Pga fell from 51.3(27.1) cmH2O to 47.4(25.2) cmH2O (p = 0.011). TwPdi did not change significantly; pre 17.0(6.4) cmH2O post 17.5(5.9) cmH2O (p = 0.7). Fatiguers, defined as having a fall TwT10Pga ? 10% had significantly worse lung gas transfer, but did not differ in other exercise parameters. Conclusions In patients with COPD, abdominal muscle but not diaphragm fatigue develops following symptom limited incremental cycle ergometry. Further work is needed to establish whether abdominal muscle fatigue is relevant to exercise limitation in COPD, perhaps indirectly through an effect on quadriceps fatigability.

2010-01-01

136

Exerciser for softball pitchers  

US Patent & Trademark Office Database

An exerciser for softball pitchers who are especially strengthening the muscles in the shoulder and arm of the user. The exerciser has a base which may be attached to a fixed frame member. A rotatable arm is held by the base, and a brake pad and shoe assembly is affixed between the rotatable arm and the base. The amount of pressure between the brake pads and the brake shoe is adjustable. A curved arm is held by the arm-support member, and a flexible line is attached at its remote end. The flexible line is about one-half the length of the curved arm. The curved arm may be rotated 360.degree. around the base.

Finch; Douglas W. (La Mirada, CA)

1993-01-12

137

Simultaneous rupture of the quadriceps tendon with contralateral patellar tendon rupture: an unusual case and a review of the literature  

Microsoft Academic Search

Simultaneous rupture of quadriceps tendon with contralateral patellar tendon is very rare. There are only two case reports\\u000a in English literature. We report the case of a healthy 41-year-old female with simultaneous rupture of her left quadriceps\\u000a tendon and right patellar tendon. There were no known precipitating factors for this injury. Surgical repair and early rehabilitation\\u000a achieved satisfactory outcome.

A. Jalgaonkar; A. Rafee; O. Haddo; S. Sarkar

2008-01-01

138

Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis  

PubMed Central

Objective To determine whether there is sufficient evidence to conclude that exercise interventions are more effective than no exercise control and to compare the effectiveness of different exercise interventions in relieving pain and improving function in patients with lower limb osteoarthritis. Data sources Nine electronic databases searched from inception to March 2012. Study selection Randomised controlled trials comparing exercise interventions with each other or with no exercise control for adults with knee or hip osteoarthritis. Data extraction Two reviewers evaluated eligibility and methodological quality. Main outcomes extracted were pain intensity and limitation of function. Trial sequential analysis was used to investigate reliability and conclusiveness of available evidence for exercise interventions. Bayesian network meta-analysis was used to combine both direct (within trial) and indirect (between trial) evidence on treatment effectiveness. Results 60 trials (44 knee, two hip, 14 mixed) covering 12 exercise interventions and with 8218 patients met inclusion criteria. Sequential analysis showed that as of 2002 sufficient evidence had been accrued to show significant benefit of exercise interventions over no exercise control. For pain relief, strengthening, flexibility plus strengthening, flexibility plus strengthening plus aerobic, aquatic strengthening, and aquatic strengthening plus flexibility, exercises were significantly more effective than no exercise control. A combined intervention of strengthening, flexibility, and aerobic exercise was also significantly more effective than no exercise control for improving limitation in function (standardised mean difference ?0.63, 95% credible interval ?1.16 to ?0.10). Conclusions As of 2002 sufficient evidence had accumulated to show significant benefit of exercise over no exercise in patients with osteoarthritis, and further trials are unlikely to overturn this result. An approach combining exercises to increase strength, flexibility, and aerobic capacity is likely to be most effective in the management of lower limb osteoarthritis. The evidence is largely from trials in patients with knee osteoarthritis. Protocol registration PROSPERO (www.crd.york.ac.uk/prospero/) No CRD42012002267.

2013-01-01

139

Segmental stabilization and muscular strengthening in chronic low back pain - a comparative study  

PubMed Central

OBJECTIVE: To contrast the efficacy of two exercise programs, segmental stabilization and strengthening of abdominal and trunk muscles, on pain, functional disability, and activation of the transversus abdominis muscle (TrA), in individuals with chronic low back pain. DESIGN: Our sample consisted of 30 individuals, randomly assigned to one of two treatment groups: segmental stabilization, where exercises focused on the TrA and lumbar multifidus muscles, and superficial strengthening, where exercises focused on the rectus abdominis, abdominus obliquus internus, abdominus obliquus externus, and erector spinae. Groups were examined to discovere whether the exercises created contrasts regarding pain (visual analogical scale and McGill pain questionnaire), functional disability (Oswestry disability questionnaire), and TrA muscle activation capacity (Pressure Biofeedback Unit ?=? PBU). The program lasted 6 weeks, and 30?minute sessions occurred twice a week. Analysis of variance was used for inter? and intra?group comparisons. The significance level was established at 5%. RESULTS: As compared to baseline, both treatments were effective in relieving pain and improving disability (p<0.001). Those in the segmental stabilization group had significant gains for all variables when compared to the ST group (p<0.001), including TrA activation, where relative gains were 48.3% and ?5.1%, respectively. CONCLUSION: Both techniques lessened pain and reduced disability. Segmental stabilization is superior to superficial strengthening for all variables. Superficial strengthening does not improve TrA activation capacity.

Franca, Fabio Renovato; Burke, Thomaz Nogueira; Hanada, Erica Sato; Marques, Amelia Pasqual

2010-01-01

140

Bonds that strengthen under force  

Microsoft Academic Search

While the adhesive strength of most receptor-ligand interactions is exponentially reduced if strained, some receptor-ligand complexes exist that strengthen under force which is the hallmark of catch bonds. Although the existence of catch bonds was theoretically predicted, the first experimental demonstrations of their existence were given only recently, i.e. for the bacterial adhesin FimH that is located at the tip

Viola Vogel

2006-01-01

141

Effects of fatiguing isometric and isotonic exercise on resisted and unresisted reaction time components  

Microsoft Academic Search

Summary  Fractionated resisted and unresisted RT for a knee-extension task was assessed on 12 male subjects over a 10-day treatment period. The first 4 days were baseline days and were designed to stabilize all RT values as well as strength measures. For the next 6 days the subjects were alternately administered isometric and isotonic exercise designed to fatigue the quadriceps musculature.

Alfred F. Morris

1977-01-01

142

Acute effects of static stretching on peak torque and the hamstrings-to-quadriceps conventional and functional ratios.  

PubMed

Recent evidence has shown acute static stretching may decrease hamstring-to-quadriceps (H:Q) ratios. However, the effects of static stretching on the functional H:Q ratio, which uses eccentric hamstrings muscle actions, have not been investigated. This study examined the acute effects of hamstrings and quadriceps static stretching on leg extensor and flexor concentric peak torque (PT), leg flexor eccentric PT, and the conventional and functional H:Q ratios. Twenty-two women (mean ± SD age=20.6 ± 1.9 years; body mass=64.6 ± 9.1 kg; height=164.5 ± 6.4 cm) performed three maximal voluntary unilateral isokinetic leg extension, flexion, and eccentric hamstring muscle actions at the angular velocities of 60 and 180°/s before and after a bout of hamstrings, quadriceps, and combined hamstrings and quadriceps static stretching, and a control condition. Two-way repeated measures ANOVAs (time × condition) were used to analyze the leg extension, flexion, and eccentric PT as well as the conventional and functional H:Q ratios. Results indicated that when collapsed across velocity, hamstrings-only stretching decreased the conventional ratios (P<0.05). Quadriceps-only and hamstrings and quadriceps stretching decreased the functional ratios (P<0.05). These findings suggested that stretching may adversely affect the conventional and functional H:Q ratios. PMID:21672027

Costa, P B; Ryan, E D; Herda, T J; Walter, A A; Defreitas, J M; Stout, J R; Cramer, J T

2011-06-15

143

Sleep On It: How Snoozing Strengthens Memories  

MedlinePLUS

... disclaimer . Subscribe Sleep On It How Snoozing Strengthens Memories When you learn something new, the best way ... sleep on it. That’s because sleeping helps strengthen memories you’ve formed throughout the day. It also ...

144

Cardiovascular benefits of exercise.  

PubMed

Regular physical activity during leisure time has been shown to be associated with better health outcomes. The American Heart Association, the Centers for Disease Control and Prevention and the American College of Sports Medicine all recommend regular physical activity of moderate intensity for the prevention and complementary treatment of several diseases. The therapeutic role of exercise in maintaining good health and treating diseases is not new. The benefits of physical activity date back to Susruta, a 600 BC physician in India, who prescribed exercise to patients. Hippocrates (460-377 BC) wrote "in order to remain healthy, the entire day should be devoted exclusively to ways and means of increasing one's strength and staying healthy, and the best way to do so is through physical exercise." Plato (427-347 BC) referred to medicine as a sister art to physical exercise while the noted ancient Greek physician Galen (129-217 AD) penned several essays on aerobic fitness and strengthening muscles. This article briefly reviews the beneficial effects of physical activity on cardiovascular diseases. PMID:22807642

Agarwal, Shashi K

2012-06-22

145

Arthrogenic Muscle Response of the Quadriceps and Hamstrings With Chronic Ankle Instability  

PubMed Central

Context: An arthrogenic muscle response (AMR) of the soleus and peroneal muscles has been previously demonstrated in individuals with chronic ankle instability (CAI), but the presence of AMR in muscles acting on joints proximal to unstable ankles has not been previously explored. Objective: To determine if AMR is present in the quadriceps and hamstrings muscles of those with and without unilateral CAI. Design: Case control. Setting: University research laboratory. Patients or Other Participants: Twenty subjects with unilateral CAI (12 males, 8 females: age = 19.9 ± 3.7 years; height = 170.3 ± 15.6 cm; mass = 78.0 ± 23.1 kg) and 21 controls (16 males, 5 females: age = 23.2 ± 5.4 years; height = 173.9 ± 12.7 cm; mass = 87.2 ± 24.6 kg) with no previous ankle injuries. Main Outcome Measure(s): The central activation ratio (CAR), a measure of motoneuron pool excitability during maximal voluntary isometric contraction, for the hamstrings and quadriceps muscles was measured in both limbs using the superimposed burst technique. Results: The CAI group demonstrated quadriceps CARs that were significantly larger in their involved limbs (.87 ± .09), as compared with their uninvolved limbs (.84 ± .08), whereas no significant side-to-side difference was seen in the control group (sham involved = .80 ± .11, sham uninvolved = .81 ± .11). When values from both the involved and uninvolved limbs were averaged, the hamstrings CAR was significantly lower for the CAI group (.94 ± .03) than for the control group (.96 ± .03). Conclusions: Arthrogenic inhibition of the hamstrings muscles bilaterally and facilitation of the quadriceps muscle ipsilateral to the involved limb were noted in subjects with unilateral CAI. Motoneuron pool excitability appears to be altered in muscles that act on joints proximal to the ankle in those with unilateral CAI.

Sedory, Edward J; McVey, Eric D; Cross, Kevin M; Ingersoll, Christopher D; Hertel, Jay

2007-01-01

146

Continuous Femoral Nerve Blocks: Decreasing Local Anesthetic Concentration to Minimize Quadriceps Femoris Weakness  

PubMed Central

Background Whether decreasing the local anesthetic concentration during a continuous femoral nerve block results in less quadriceps weakness remains unknown. Methods Preoperatively, bilateral femoral perineural catheters were inserted in patients undergoing bilateral knee arthroplasty (n = 36) at a single clinical center. Postoperatively, right-sided catheters were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 mL/h; bolus 4 mL) or 0.4% (basal 3 mL/h; bolus 1 mL), with the left catheter receiving the alternative concentration/rate in an observer- and subject-masked fashion. The primary endpoint was the maximum voluntary isometric contraction of the quadriceps femoris muscles the morning of postoperative day 2. Equivalence of treatments would be concluded if the 95% confidence interval for the difference fell within the interval of ?20% to 20%. Secondary endpoints included active knee extension, passive knee flexion, tolerance to cutaneous electrical current applied over the distal quadriceps tendon, dynamic pain scores, opioid requirements, and ropivacaine consumption. Results Quadriceps maximum voluntary isometric contraction for limbs receiving 0.1% ropivacaine was a mean (SD) of 13 (8) N·m, versus 12 (8) N·m for limbs receiving 0.4% [intra-subject difference of 3 (40) percentage points; 95% CI ?10 to 17; p = 0.63]. Because the 95% confidence interval fell within prespecified tolerances, we conclude that the effect of the two concentrations were equivalent. Similarly, there were no statistically significant differences in secondary endpoints. Conclusions For continuous femoral nerve blocks, we found no evidence that local anesthetic concentration and volume influence block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Bauer, Maria; Wang, Lu; Onibonoje, Olusegun K.; Parrett, Chad; Sessler, Daniel I.; Mounir-Soliman, Loran; Zaky, Sherif; Krebs, Viktor; Buller, Leonard T.; Donohue, Michael C.; Stevens-Lapsley, Jennifer E.; Ilfeld, Brian M.

2012-01-01

147

The relationship between plasma potassium, muscle membrane excitability and force following quadriceps fatigue  

Microsoft Academic Search

To examine the simultaneous changes in plasma [K+], muscle excitability and force during fatigue, ten male adults (mean age = 22 ± 0.5 years) held an isometric contraction\\u000a of their right quadriceps muscle at an intensity of 30% maximum voluntary contraction (MVC) for 3 min. Femoral venous and\\u000a brachial arterial [K+] were determined from serial samples drawn before, during, and

A. Hicks; R. McKelvie; J. O’Brien

1996-01-01

148

Relaxation and force during fatigue and recovery of the human quadriceps muscle: relations to metabolite changes  

Microsoft Academic Search

Force and relaxation were measured during electrical stimulation of the quadriceps muscle of 14 volunteers. Stimulation produced 51.2 s of intermittent ischaemic contractions either as 16 3.2-s tetani or as 64 0.8-s tetani. Changes during recovery were followed for 180 s. On 8 subjects muscle biopsies were taken during work and after the rest period for determination of ATP, phosphocreatine

M. Bergström; E. Hultman

1991-01-01

149

A dynamic warm-up model increases quadriceps strength and hamstring flexibility.  

PubMed

Research suggests that static stretching can negatively influence muscle strength and power and may result in decreased functional performance. The dynamic warm-up (DWU) is a common alternative to static stretching before physical activity, but there is limited research investigating the effects of a DWU. The purpose of this study was to compare the acute effects of a DWU and static stretching warm-up (SWU) on muscle flexibility, strength, and vertical jump using a randomized controlled trial design. Forty-five volunteers were randomly assigned into a control (CON), SWU, or DWU group. All participants rode a stationary bicycle for 5 minutes and completed a 10-minute warm-up protocol. During this protocol, the DWU group performed dynamic stretching and running, the SWU group performed static stretching, and the CON group rested. Dependent variables were measured immediately before and after the warm-up protocol. A digital inclinometer measured flexibility (degrees) for the hamstrings, quadriceps, and hip flexor muscles. An isokinetic dynamometer measured concentric and eccentric peak torque (N·m/kg) for the hamstrings and quadriceps. A force plate was used to measure vertical jump height (meters) and power (watts). In the DWU group, there was a significant increase in hamstring flexibility (pretest: 26.4 ± 13.5°, posttest: 16.9 ± 9.4°; p < .0001) and eccentric quadriceps peak torque (pretest: 2.49 ± 0.83 N·m/kg, posttest: 2.78 ± 0.69 N·m/kg; p = 0.04). The CON and SWU did not significantly affect any flexibility, strength, or vertical jump measures (p > 0.05). The DWU significantly improved eccentric quadriceps strength and hamstrings flexibility, whereas the SWU did not facilitate any positive or negative changes in muscle flexibility, strength, power, or vertical jump. Therefore, the DWU may be a better preactivity warm-up choice than an SWU. PMID:22446678

Aguilar, Alain J; DiStefano, Lindsay J; Brown, Cathleen N; Herman, Daniel C; Guskiewicz, Kevin M; Padua, Darin A

2012-04-01

150

Concentric and eccentric strength profile of quadriceps and hamstrings in healthy volleyball players  

Microsoft Academic Search

BackgroundLower-extremity strength profile can be used in injury prevention, conditioning and rehabilitation of volleyball players.ObjectivesThe goals were: (1) to describe the concentric and eccentric quadriceps (Q) and hamstrings (H) muscle function in volleyball players, (2) to evaluate the differences in Q and H strength, strength ratios and bilateral strength asymmetry among age groups, playing positions and playing levels, (3) to

V Hadzic; E Dervisevic; M Veselko

2011-01-01

151

An in vivo rodent model of contraction-induced injury in the quadriceps muscle.  

PubMed

Most animal studies of muscle contractile function utilise the anterior or posterior crural muscle (dorsiflexors and plantarflexors, respectively). An advantage to using these muscles is that the common fibular and tibial nerves are readily accessible, while the small size of the crural muscles is a disadvantage. Working with small muscles not only makes some in vivo imaging and the muscle testing techniques more challenging, but also provides limited amounts of tissue to study. The purpose of this study was to describe a new animal muscle injury model in the quadriceps that results in a significant and reproducible loss of force. The thigh of Sprague Dawley rats (N=5) and C57BL/10 mice (N=5) was immobilised and the ankle was attached to a custom-made lever arm. The femoral nerve was stimulated using subcutaneous electrodes and injury was induced using 50 lengthening ("eccentric") contractions through a 70° arc of knee motion. This protocol produces a significant and reproducible injury, with comparable susceptibility to injury in the rats and mice. This novel model shows that the quadriceps muscle provides a means to study whole muscle contractility, injury, and recovery in vivo. In addition to the usual benefits of an in vivo model, the larger size of the quadriceps facilitates in vivo imaging and provides a significant increase in the amount of tissue available for histology and biochemistry studies. A controlled muscle injury in the quadriceps also allows one to study a muscle, with mixed fibre types, which is extremely relevant to gait in humans and quadruped models. PMID:22001505

Pratt, Stephen J P; Lawlor, Michael W; Shah, Sameer B; Lovering, Richard M

2011-10-14

152

Force enhancement during and following muscle stretch of maximal voluntarily activated human quadriceps femoris  

Microsoft Academic Search

Force enhancement during and following muscle stretch has been observed for electrically and voluntarily activated human muscle.\\u000a However, especially for voluntary contractions, the latter observation has only been made for adductor pollicis and the ankle\\u000a joint muscles, but not for large muscles like quadriceps femoris. Therefore, the aim of this study was to investigate the\\u000a effects of active muscle stretch

Daniel Hahn; Wolfgang Seiberl; Ansgar Schwirtz

2007-01-01

153

The influence of maximal isometric activity on twitch and H -reflex potentiation, and quadriceps femoris performance  

Microsoft Academic Search

The possibility of post-activation potentiation (PAP), enhanced neuromuscular performance following prior contractile activity,\\u000a has received considerable attention but with little assessment of physiological changes. Maximum twitch force and H-reflex amplitude can be used to quantify the effect of prior activity, and may account for any PAP. Quadriceps femoris maximum\\u000a twitch force (twitch potentiation, TP), the EMG Hmax\\/Mmax ratio and associated

Jonathan P. Folland; Tomoyoshi Wakamatsu; Marius S. Fimland

2008-01-01

154

Carnosine and anserine concentrations in the quadriceps femoris muscle of healthy humans  

Microsoft Academic Search

Summary  The content of anserine and carnosine in the lateral portion of the quadriceps femoris muscle of 50 healthy, human subjects has been studied. Anserine was undetectable in all muscle samples examined. Muscle carnosine values for the group conformed to a normal distribution with a mean (SD) value of 20.0 (4.7) mmol · kg–1 of dry muscle mass. The concentration of

A. F. Mannion; P. M. Jakeman; M. Dunnett; R. C. Harris; P. L. T. Willan

1992-01-01

155

Quadriceps fat pad edema: significance on magnetic resonance images of the knee  

Microsoft Academic Search

Objective  While clinically reading magnetic resonance (MR) images of the knees we have occasionally noted edema within the suprapatellar\\u000a fat pad, with mass effect both on the suprapatellar joint recess posteriorly, and on the quadriceps tendon anteriorly. This\\u000a MR appearance is analogous to Hoffa’s disease described in the infrapatellar fat pad. We sought to evaluate the frequency\\u000a and pattern of this

Nogah Shabshin; Mark E. Schweitzer; William B. Morrison

2006-01-01

156

Exercise Headaches  

MedlinePLUS

Exercise headaches Basics In-Depth Resources Reprints A single copy of this article may be reprinted for personal, noncommercial use only. Exercise headaches By Mayo Clinic staff Original Article: http:// ...

157

Compulsive Exercise  

MedlinePLUS

... overdoing it for almost anyone. Much like with eating disorders, many people who engage in compulsive exercise do ... compulsive exercising doesn't have to accompany an eating disorder, the two often go hand in hand. In ...

158

Functional Plyometric Exercises for the Throwing Athlete  

PubMed Central

In this article we provide athletic health care professionals with a variety of functional strengthening exercises to use in improving the muscular strength of the throwing athlete's shoulder. Upper extremity functional plyometric exercise in sport-specific patterns can be an important component of a throwing athlete's rehabilitation. We discuss several plyometric exercises, using the Inertial Exercise System, the Plyo-ball, and the Theraband. Proper use of these exercises can facilitate a safe and progressive rehabilitation program for the injured, throwing athlete. After the athlete has successfully completed the functional plyometric exercises, a throwing progression can be initiated. ImagesFig 1.Fig 2.Fig 3.Fig 4.Fig 5.Fig 6.Fig 7.Fig 8.Fig 9.Fig 10.Fig 11.Fig 12.Fig 13.Fig 14.Fig 15.

Pezzullo, David J.; Karas, Steven; Irrgang, James J

1995-01-01

159

An in vivo analysis of the effect of transcutaneous electrical stimulation of the quadriceps and hamstrings on anterior cruciate ligament deformation  

Microsoft Academic Search

Transcutaneous electrical muscle stimulation (TEMS) has been advocated as a method to rehabilitate the postoperative ACL repaired\\/reconstructed lower ex tremity. Isolated quadriceps contraction can potentially disrupt the ACL repair\\/reconstruction; to minimize this risk simultaneous quadriceps and hamstring stimulation has been used. This study measured the in vivo defor mation of the ACL during TEMS of the quadriceps and hamstrings.Six legs

Christopher C. Kain; John A. McCarthy; Steve Arms; Malcolm H. Pope; J. Richard Steadman; Paul R. Manske; Robert A. Shively

1988-01-01

160

Analysis of the effect of horseback riding exercise equipment on the human body  

Microsoft Academic Search

The purpose of this study was to investigate the effect of indoor horseback riding exercise equipment on the human body. Subjects performed horseback riding exercise using Slim-Rider. We used human body effect methods to analyze the exercise effect. We classified the effects into flexibility, muscle strengthening, and muscular reaction. Twenty male and 20 female subjects were included. They had no

Seung-Rok Kang; Gu-Young Jung; Dong-An Moon; Song-Sik Choi; Jung-Ja Kim; Tae-Kyu Kwon

2012-01-01

161

Exercise addiction.  

PubMed

This article examines the nature of exercise addiction. It presents a broad, congruent and discerning narrative literature review with the aim of providing a deeper understanding of the condition 'exercise addiction', including symptoms and options for treatment. In addition, guidelines are provided with respect to 'healthy' levels of exercise. Criteria used for determining the eligibility of studies evaluated in the review included the provision of relevant information in studies identified using pertinent search terms. The review highlights some of the key distinctions between healthy levels of exercise and exercise addiction. The findings suggest that an individual who is addicted to exercise will continue exercising regardless of physical injury, personal inconvenience or disruption to other areas of life including marital strain, interference with work and lack of time for other activities. 'Addicted' exercisers are more likely to exercise for intrinsic rewards and experience disturbing deprivation sensations when unable to exercise. In contrast, 'committed' exercisers engage in physical activity for extrinsic rewards and do not suffer severe withdrawal symptoms when they cannot exercise. Exercisers must acquire a sense of life-balance while embracing an attitude conducive to sustainable long-term physical, psychological and social health outcomes. Implementation of recommendations by the Canadian Society for Exercise Physiology, which states that all apparently healthy adults between 18 and 64 years of age should accumulate at least 150 minutes of moderate (5 or 6 on a scale of 0-10) to vigorous (7 or 8 on a scale of 0-10) intensity aerobic physical activity per week in bouts of 10 minutes or more, also expressed as 30 minutes per day distributed over 5 days per week, would be a good start. PMID:23329605

Landolfi, Emilio

2013-02-01

162

Rethinking health research capacity strengthening.  

PubMed

Health research capacity strengthening (HRCS) is a strategy implemented worldwide to improve the ability of developing countries to tackle the persistent and disproportionate burdens of disease they face. Drawing on a review of existing HRCS literature and our experiences over the course of an HRCS project in Vietnam, we summarise major challenges to the HRCS enterprise at the interpersonal, institutional and macro levels. While over the course of several decades of HRCS initiatives many of these challenges have been well documented, we highlight several considerations that remain underarticulated. We advance critical considerations of the HRCS enterprise by discussing (1) how the organisation of US public health funding shapes the ecology of knowledge production in low- and middle-income country contexts, (2) the barriers US researchers face to effectively collaborate in capacity strengthening for research-to-policy translation, and (3) the potential for unintentional negative consequences if HRCS efforts are not sufficiently reflexive about the limitations of dominant paradigms in public health research and intervention. PMID:23651463

Vasquez, Emily E; Hirsch, Jennifer S; Giang, Le Minh; Parker, Richard G

2013-05-07

163

Exercise at Home  

MedlinePLUS

... Health Information > Healthy Lifestyle > Exercise > Exercise at Home Exercise at Home Exercise and staying active are an ... plans to begin exercising with your doctor. Posture Exercises Better poster means better breathing and movement. Axial ...

164

Group III and IV muscle afferents contribute to ventilatory and cardiovascular response to rhythmic exercise in humans  

PubMed Central

We investigated the role of somatosensory feedback on cardioventilatory responses to rhythmic exercise in five men. In a double-blind, placebo-controlled design, subjects performed the same leg cycling exercise (50/100/150/325 ± 19 W, 3 min each) under placebo conditions (interspinous saline, L3–L4) and with lumbar intrathecal fentanyl impairing central projection of spinal opioid receptor-sensitive muscle afferents. Quadriceps strength was similar before and after fentanyl administration. To evaluate whether a cephalad migration of fentanyl affected cardioventilatory control centers in the brain stem, we compared resting ventilatory responses to hypercapnia (HCVR) and cardioventilatory responses to arm vs. leg cycling exercise after each injection. Similar HCVR and minor effects of fentanyl on cardioventilatory responses to arm exercise excluded direct medullary effects of fentanyl. Central command during leg exercise was estimated via quadriceps electromyogram. No differences between conditions were found in resting heart rate (HR), ventilation [minute ventilation (V?e)], or mean arterial pressure (MAP). Quadriceps electromyogram, O2 consumption (V?o2), and plasma lactate were similar in both conditions at the four steady-state workloads. Compared with placebo, a substantial hypoventilation during fentanyl exercise was indicated by the 8–17% reduction in V?e/CO2 production (V?co2) secondary to a reduced breathing frequency, leading to average increases of 4–7 Torr in end-tidal Pco2 (P < 0.001) and a reduced hemoglobin saturation (?3 ± 1%; P < 0.05) at the heaviest workload (?90% maximal V?o2) with fentanyl. HR was reduced 2–8%, MAP 8–13%, and ratings of perceived exertion by 13% during fentanyl vs. placebo exercise (P < 0.05). These findings demonstrate the essential contribution of muscle afferent feedback to the ventilatory, cardiovascular, and perceptual responses to rhythmic exercise in humans, even in the presence of unaltered contributions from other major inputs to cardioventilatory control.

Blain, Gregory M.; Proctor, Lester T.; Sebranek, Joshua J.; Pegelow, David F.; Dempsey, Jerome A.

2010-01-01

165

Knee Exercises  

MedlinePLUS

... to keep knees healthy and prevent further injury. Strength Strengthening the muscles that support your knee will ... are right for you. Start slowly. Building muscle strength takes time. As you get stronger, gradually increase ...

166

The effects of high-fat diet, branched-chain amino acids and exercise on female C57BL/6 mouse Achilles tendon biomechanical properties  

PubMed Central

Objectives The goals of this study were: 1) to determine if high-fat diet (HFD) feeding in female mice would negatively impact biomechanical and histologic consequences on the Achilles tendon and quadriceps muscle; and 2) to investigate whether exercise and branched-chain amino acid (BCAA) supplementation would affect these parameters or attenuate any negative consequences resulting from HFD consumption. Methods We examined the effects of 16 weeks of 60% HFD feeding, voluntary exercise (free choice wheel running) and BCAA administration in female C57BL/6 mice. The Achilles tendons and quadriceps muscles were removed at the end of the experiment and assessed histologically and biomechanically. Results HFD feeding significantly decreased the Achilles tendon modulus without histological alterations. BCAA administration significantly decreased the stiffness of Achilles tendons in the exercised normal diet mice. Exercise partially ameliorated both the weight gain and glucose levels in the HFD-fed mice, led to a significant decrease in the maximum load of the Achilles tendon, and an increase in the average fibril diameter of the quadriceps femoris muscle. There were significant correlations between body weight and several biomechanical properties, demonstrating the importance of controlling obesity for maintaining healthy tendon properties. Conclusions In summary, this study showed a significant impact of obesity and body weight on tendon biomechanical properties with limited effects of exercise and BCAAs. Cite this article: Bone Joint Res 2013;2:186–92.

Boivin, G. P.; Platt, K. M.; Corbett, J.; Reeves, J.; Hardy, A. L.; Elenes, E. Y.; Charnigo, R. J.; Hunter, S. A.; Pearson, K. J.

2013-01-01

167

Prevalence of Muscle-Strengthening Activities in Women: The WIN Study.  

PubMed

Background: Aerobic and muscle-strengthening activities are related to morbidities and mortality. Resistance exercise/strength training items are included in national surveys, but the manner in which muscle-strengthening activity is queried varies among these surveys. Purpose: The purpose of this study was to use different self-report measures to examine the prevalence of meeting the 2008 Physical Activity Guidelines for Americans regarding muscle-strengthening activities among women. Methods: We surveyed 606 community-dwelling women at 4 points in time across a 1.5- to 3-year time period to determine whether the respondents met the national physical activity guidelines for performing muscle-strengthening activities ??2 days per week. Results: Results were consistent across time but depended on the manner in which the question was asked. If asked to reflect over the past month or a general question about the typical number of days engaged, approximately 40% of women reported engaging in ??2 days per week of resistance exercise/strength training. However, when reports were obtained weekly for 13 weeks, only approximately 18% of respondents met the guidelines. Conclusion: Results indicate that the timing and nature of questioning can substantially influence the self-reported prevalence of muscle-strengthening physical activities for community-dwelling women. PMID:24051534

Vingren, Jakob L; Morrow, James R; Trudelle-Jackson, Elaine; Mathew, Merly T

2013-09-01

168

Adaptive Force Regulation of Muscle Strengthening Rehabilitation Device With Magnetorheological Fluids  

PubMed Central

In rehabilitation from neuromuscular trauma or injury, strengthening exercises are often prescribed by physical therapists to recover as much function as possible. Strengthening equipment used in clinical settings range from low-cost devices, such as sandbag weights or elastic bands to large and expensive isotonic and isokinetic devices. The low-cost devices are incapable of measuring strength gains and apply resistance based on the lowest level of torque that is produced by a muscle group. Resistance that varies with joint angle can be achieved with isokinetic devices in which angular velocity is held constant and variable torque is generated when the patient attempts to move faster than the device but are ineffective if a patient cannot generate torque rapidly. In this paper, we report the development of a versatile rehabilitation device that can be used to strengthen different muscle groups based on the torque generating capability of the muscle that changes with joint angle. The device is low cost, is smaller than other commercially available machines, and can be programmed to apply resistance that is unique to a particular patient and that will optimize strengthening. The core of the device, a damper with smart magnetorheological fluids, provides passive exercise force. A digital adaptive control is capable of regulating exercise force precisely following the muscle strengthening profile prescribed by a physical therapist. The device could be programmed with artificial intelligence to dynamically adjust the target force profile to optimize rehabilitation effects. The device provides both isometric and isokinetic strength training and can be developed into a small, low-cost device that may be capable of providing optimal strengthening in the home.

Dong, Shufang; Lu, Ke-Qian; Sun, Jian Qiao; Rudolph, Katherine

2008-01-01

169

Laser strengthening of tool steels  

NASA Astrophysics Data System (ADS)

This paper presents results of SEM, microhardness, residual stress (measured using Weissman-Philips method) and abrasion resistance examination of a surface layer of the tools steels remelted with a laser beam. Laser remelting of the tool steels provides strengthening an increase of the surface layer as a result of formation of highly refined, nonequilibrium products of the austenite transformation. There is obtained an increase of microhardness and abrasion resistance of the surface layer in relation to traditionally heat treated steels. The influence of the tempering temperature after a laser hardening on the distribution and the residual stresses values was also examined. The values of the stresses decrease with the distance from the surface treated. Tempering steels after a laser treatment led to decreased values of the residual stresses by about 30 to 50 MPa.

Adamiak, Stanislaw; Bochnowski, Wojciech; Dziedzic, Andrzej

2007-02-01

170

Exercise intolerance.  

PubMed

Patients with heart failure and normal EF have severe chronic exercise intolerance. The pathophysiology of exercise intolerance in this syndrome is incompletely understood, but as in systolic heart failure, it is likely multifactorial. Current data suggest that important contributors include decreased LV diastolic compliance, decreased aortic distensibility, exaggerated exercise systolic blood pressure, relative chronotropic incompetence, and possibly anemia and skeletal muscle remodeling. Because it is a primary determinant of quality of life, can be quantified objectively, is reproducible, and is modifiable, exercise intolerance is an attractive therapeutic target. PMID:16115516

Kitzman, Dalane W

171

Measurements of the quadriceps femoris function after meniscus refixation at the stable athlete’s knee  

Microsoft Academic Search

Introduction  The purpose of this study was to monitor the muscular changes regarding the isokinetic strength and torque pattern of the\\u000a quadriceps femoris at the stable athlete’s knee after meniscus tear refixation.\\u000a \\u000a \\u000a \\u000a Materials and methods  Therefore 15 athletes (10 male, 5 female) performing recreational or competitional sports at least five times a week before\\u000a injury were retrospectively examined in the average 2.5 years

T. Stein; A. P. Mehling; K. Jost; T. C. Auhuber; A. Jäger

2009-01-01

172

Localized pigmented villonodular synovitis: arthroscopic treatment of a lesion arising from the quadriceps tendon sheath.  

PubMed

Pigmented villonodular synovitis (PVNS) is a rare benign proliferative growth of synovium of obscure etiology with a wide spectrum of clinical presentation. Localized PVNS, also known as giant cell tumor of the tendon sheath, is even more uncommon. Localized PVNS of the knee is a rare, idiopathic condition presenting with symptoms that can mimic other intra-articular pathologies. The condition is usually monoarticular, the knee being the most commonly affected joint. We report a rare case of PVNS arising from the quadriceps tendon sheath. It was successfully treated with arthroscopic intralesional excision. At 18 months' follow-up, there has been no recurrence. PMID:17418347

Kakarala, Gopikrishna; Peddu, Praveen; Lahoti, Om

2006-10-16

173

Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation  

Microsoft Academic Search

We hypothesize that application of an unopposed quadriceps force coupled with an impulsive ground reaction force may induce anterior cruciate ligament (ACL) injury. This situation is similar to landing from a jump if only the quadriceps muscle is active; an unlikely but presumably dangerous circumstance. The purpose of this study was to test our hypothesis using in vitro simulation of

Javad Hashemi; Ryan Breighner; Taek-Hyun Jang; Naveen Chandrashekar; Stephen Ekwaro-Osire; James R. Slauterbeck

2010-01-01

174

Early Neuromuscular Electrical Stimulation to Improve Quadriceps Muscle Strength After Total Knee Arthroplasty: A Randomized Controlled Trial  

PubMed Central

Background The recovery of quadriceps muscle force and function after total knee arthroplasty (TKA) is suboptimal, which predisposes patients to disability with increasing age. Objective The purpose of this investigation was to evaluate the efficacy of quadriceps muscle neuromuscular electrical stimulation (NMES), initiated 48 hours after TKA, as an adjunct to standard rehabilitation. Design This was a prospective, longitudinal randomized controlled trial. Methods Sixty-six patients, aged 50 to 85 years and planning a primary unilateral TKA, were randomly assigned to receive either standard rehabilitation (control) or standard rehabilitation plus NMES applied to the quadriceps muscle (initiated 48 hours after surgery). The NMES was applied twice per day at the maximum tolerable intensity for 15 contractions. Data for muscle strength, functional performance, and self-report measures were obtained before surgery and 3.5, 6.5, 13, 26, and 52 weeks after TKA. Results At 3.5 weeks after TKA, significant improvements with NMES were found for quadriceps and hamstring muscle strength, functional performance, and knee extension active range of motion. At 52 weeks, the differences between groups were attenuated, but improvements with NMES were still significant for quadriceps and hamstring muscle strength, functional performance, and some self-report measures. Limitations Treatment volume was not matched for both study arms; NMES was added to the standard of care treatment. Furthermore, testers were not blinded during testing, but used standardized scripts to avoid bias. Finally, some patients reached the maximum stimulator output during at least one treatment session and may have tolerated more stimulation. Conclusions The early addition of NMES effectively attenuated loss of quadriceps muscle strength and improved functional performance following TKA. The effects were most pronounced and clinically meaningful within the first month after surgery, but persisted through 1 year after surgery.

Balter, Jaclyn E.; Wolfe, Pamela; Eckhoff, Donald G.; Kohrt, Wendy M.

2012-01-01

175

GNE mutations in an American family with quadriceps-sparing IBM and lack of mutations in s-IBM.  

PubMed

Analysis for GNE mutations was performed in an American, non-Iranian Jewish, family with quadriceps-sparing inclusion body myopathy (QS-IBM) and in 11 patients with sporadic IBM (s-IBM). Two novel nonallosteric site missense mutations were found in the QS-IBM kinship. No mutations were identified in s-IBM patients. After 8 years of follow-up and severe disease progression, the quadriceps muscle in the QS-IBM patient remains strong despite subclinical involvement documented with repeat MRI and muscle biopsy. PMID:12473769

Vasconcelos, Olavo M; Raju, Raghavan; Dalakas, Marinos C

2002-12-10

176

Exercise caution.  

PubMed

A recent study into the effects of structured physical exercise for people diagnosed with depression claimed that it did not help. The findings attracted huge media coverage that may have made it harder to persuade patients with depression to take exercise. PMID:22930958

Trueland, Jennifer

177

Mutations spectrum of GNE in hereditary inclusion body myopathy sparing the quadriceps.  

PubMed

Hereditary Inclusion Body Myopathy (HIBM) is a unique group of neuromuscular disorders characterized by adult onset and a typical muscle pathology. We have recently identified the gene encoding for a bifunctional enzyme, UDP-N-acetylglucosamine 2 epimerase/N-acetylmannosamine kinase (GNE), as the mutated gene in the prototype form of the disease presenting quadriceps sparing, particularly common in Middle Eastern Jews. Interestingly, we have identified the homozygous M712T Middle Eastern Jewish mutation also in two unrelated Middle Eastern Moslem families. We have also evaluated the involvement of GNE in several families from worldwide non-Jewish ethnic origins presenting symptoms similar to the Middle Eastern HIBM prototype. A total of 14 GNE mutations were identified (one nonsense and 13 missense), of which six are novel: an homozygous missense mutation in a consanguineous family from Italy and in a non consanguineous family from USA, and distinct compound heterozygotes in families from Germany, Italy, Ireland, Bahamas, USA and East India. This study brings to 17 the number of reported GNE mutations in quadriceps sparing myopathy, occurring either in the epimerase or the kinase domain of the enzyme. The mechanism leading to this unique phenotype still remains to be elucidated. PMID:12497639

Eisenberg, Iris; Grabov-Nardini, Gil; Hochner, Hagit; Korner, Mira; Sadeh, Menachem; Bertorini, Tulio; Bushby, Kate; Castellan, Claudio; Felice, Kevin; Mendell, Jerry; Merlini, Luciano; Shilling, Christopher; Wirguin, Itshak; Argov, Zohar; Mitrani-Rosenbaum, Stella

2003-01-01

178

Influence of Local Cooling on Proprioceptive Acuity in the Quadriceps Muscle  

PubMed Central

Objective: To test the influence of cooling on proprioceptive acuity as reflected in the ability to discriminate weights. Design and Setting: Participants were trained to perform a weight-discrimination task. Their ability to correctly report small increments in weight was compared before and after local cooling (a 20-minute application of a crushed-ice pack) of the quadriceps muscle group. Data were collected at a university research laboratory. Subjects: Twenty young, physically active adults (undergraduate students; 14 men, 6 women; mean age, 22.1 ± 2.6 years). Measurements: We calculated overall performance in the weight-discrimination task (percentage of discrimination correct) for each participant to estimate the differential threshold (ie, minimal increment in weight that yields a probability of 75% correct responses). Results: Before local cooling, participants discriminated increments in the order of 4% to 10% from the standard weight (mean threshold, 0.17 ± 0.06 kg). After local cooling, the discriminative performance remained, on average, very similar to that seen before cooling (mean threshold, 0.17 ± 0.08 kg; paired t test: t = 0.24, P = .81). Only a small group of participants (n = 5) showed evidence of a decreased ability to discriminate weight after cooling. Conclusions: The perception of force signals required for weight discrimination does not appear to be affected by local cooling of the quadriceps muscle group. This finding provides additional evidence for the relative safety of cold applications and their effect on proprioceptive perceptual abilities.

Estephan, Lorein; Legendre, Martine; Sulpher, Stephanie

2001-01-01

179

Influence of Local Cooling on Proprioceptive Acuity in the Quadriceps Muscle.  

PubMed

OBJECTIVE: To test the influence of cooling on proprioceptive acuity as reflected in the ability to discriminate weights. DESIGN AND SETTING: Participants were trained to perform a weight-discrimination task. Their ability to correctly report small increments in weight was compared before and after local cooling (a 20-minute application of a crushed-ice pack) of the quadriceps muscle group. Data were collected at a university research laboratory. SUBJECTS: Twenty young, physically active adults (undergraduate students; 14 men, 6 women; mean age, 22.1 +/- 2.6 years). MEASUREMENTS: We calculated overall performance in the weight-discrimination task (percentage of discrimination correct) for each participant to estimate the differential threshold (ie, minimal increment in weight that yields a probability of 75% correct responses). RESULTS: Before local cooling, participants discriminated increments in the order of 4% to 10% from the standard weight (mean threshold, 0.17 +/- 0.06 kg). After local cooling, the discriminative performance remained, on average, very similar to that seen before cooling (mean threshold, 0.17 +/- 0.08 kg; paired t test: t = 0.24, P =.81). Only a small group of participants (n = 5) showed evidence of a decreased ability to discriminate weight after cooling. CONCLUSIONS: The perception of force signals required for weight discrimination does not appear to be affected by local cooling of the quadriceps muscle group. This finding provides additional evidence for the relative safety of cold applications and their effect on proprioceptive perceptual abilities. PMID:12937450

Tremblay, François; Estephan, Lorein; Legendre, Martine; Sulpher, Stéphanie

2001-06-01

180

Reconstruction of the medial patellofemoral ligament using a quadriceps tendon graft: a case series.  

PubMed

This study assessed medial patellofemoral ligament reconstruction using a partial-thickness quadriceps tendon graft in 14 knees in 13 patients. Nine patients were available for follow-up after a minimum of 24 months. Final patient evaluation was performed an average of 42 months postoperatively (range, 28-65 months). Primary outcome measure was occurrence of patellar dislocation postoperatively, and outcomes were quantified using the Kujala questionnaire and Crosby and Insall criteria. Postoperatively, no patient reported patellar dislocation. Using Crosby and Insall criteria, good or excellent results were achieved in 100% of patients. Mean Kujala score was 91.9. Postoperatively, all patients reported their knee was improved. These findings indicate medial patellofemoral ligament reconstruction with a quadriceps tendon graft is effective in preventing patellar dislocation and improving quality of life. However, patients should be counseled this procedure is indicated primarily for the treatment of recurrent instability, and postoperative relief of anterior knee pain is inconsistent. Level of Evidence: Level IV, Case Series. PMID:19292257

Dopirak, Ryan; Adamany, Damon; Bickel, Brent; Steensen, Robert

2008-03-01

181

Quadriceps function assessment using an incremental test and magnetic neurostimulation: a reliability study.  

PubMed

We investigated the reliability of a test assessing quadriceps strength, endurance and fatigability in a single session. We used femoral nerve magnetic stimulation (FMNS) to distinguish central and peripheral factors of neuromuscular fatigue. We used a progressive incremental loading with multiple assessments to limit the influence of subject's cooperation and motivation. Twenty healthy subjects (10 men and 10 women) performed the test on two different days. Maximal voluntary strength and evoked quadriceps responses via FMNS were measured before, after each set of 10 submaximal isometric contractions (5-s on/5-s off; starting at 10% of maximal voluntary strength with 10% increments), immediately and 30min after task failure. The test induced progressive peripheral (41±13% reduction in single twitch at task failure) and central fatigue (3±7% reduction in voluntary activation at task failure). Good inter-day reliability was found for the total number of submaximal contractions achieved (i.e. endurance index: ICC=0.83), for reductions in maximal voluntary strength (ICC>0.81) and evoked muscular responses (i.e. fatigue index: ICC>0.85). Significant sex-differences were also detected. This test shows good reliability for strength, endurance and fatigability assessments. Further studies should be conducted to evaluate its feasibility and reliability in patients. PMID:23265662

Bachasson, Damien; Millet, Guillaume Y; Decorte, Nicolas; Wuyam, Bernard; Levy, Patrick; Verges, Samuel

2012-12-20

182

Strengthening the public health system.  

PubMed Central

Although the American public health system has made major contributions to life expectancy for residents of this country over the past century, the system now faces more complex health problems that require comprehensive approaches and increased capacity, particularly in local and State public health agencies. To strengthen the public health system, concerted action is needed to meet these five critical needs: First, the knowledge base of public health workers needs to be supplemented through on-the-job training and continuing education programs. To this end, self-study courses will be expanded, and a network of regional training centers will be established throughout the country. Second, communities need dynamic leadership from public health officials and their agencies. To enhance leadership skills and expand the leadership role of public health agencies, focused personal leadership development activities, including a Public Health Leadership Institute, and national conferences will provide a vision of the future role of public health agencies. Third, local and State public health agencies need access to data on the current health status of the people in their communities and guidance from the nation's public health experts. To improve access to information resources, state-of-the-art technologies will be deployed to create integrated information and communication systems linking all components of the public health system. Fourth, local and State agencies need disease prevention and health promotion plans that target problems and develop strategies and the capacity to address them.(ABSTRACT TRUNCATED AT 250 WORDS)

Roper, W L; Baker, E L; Dyal, W W; Nicola, R M

1992-01-01

183

Exercise-induced knee joint laxity in distance runners.  

PubMed Central

The objectives of this study were to evaluate the effect of exercise on knee joint laxity. If exercise induced laxity is physiological, incorporation of this quality into a ligament replacement material would be indicated. Twenty recreational long distance runners average age 41 (range 24 to 50 yr) were tested before and immediately after 30 minutes of running. Using a computerized goniometer type instrument (Acufex KSS), knee flexion, axial tibial rotation and anterior-posterior tibial displacement were simultaneously recorded, while the runners underwent tests of static as well as dynamic knee joint laxity. At 30 degrees of knee flexion, a maximum increase of 16 per cent in mean total anterior-posterior laxity post-exercise was found. At the examination 30 minutes post-exercise, laxity at 30 degrees of knee flexion was still increased. However, laxity at 90 degrees of knee flexion had decreased to pre-exercise levels or below. Anterior tibial displacement, recorded during eccentric quadriceps activity (0 to 90 degrees of knee flexion) with weights attached to the foot, showed a maximum of 18 per cent increase in total anterior-posterior laxity post-exercise. It is suggested that the laxity increase is caused in part by a true ligamentous laxity increase, and in part by a decreased resting tone of the fatigued muscles.

Johannsen, H V; Lind, T; Jakobsen, B W; Kr?ner, K

1989-01-01

184

Exercise and age  

MedlinePLUS

Age and exercise ... It's never too late to start exercising. Exercise has benefits at any age. Don't worry if you've never exercised, or if you stopped exercising for some reason. Being physically ...

185

A low dose of alcohol does not impact skeletal muscle performance after exercise-induced muscle damage.  

PubMed

Moderate, acute alcohol consumption after eccentric exercise has been shown to magnify the muscular weakness that is typically associated with exercise-induced muscle damage (EIMD). As it is not known whether this effect is dose-dependent, the aim of this study was to investigate the effect of a low dose of alcohol on EIMD-related losses in muscular performance. Ten healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed either a beverage containing 0.5 g of alcohol per kg bodyweight (as vodka and orange juice) or an isocaloric, isovolumetric non-alcoholic beverage. At least 2 weeks later, they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed the other beverage. Measurement of peak and average peak isokinetic (concentric and eccentric) and isometric torque produced by the quadriceps was made before and 36 and 60 h post-exercise. Significant decreases in all measures of muscular performance were observed over time under both conditions (all P < 0.05); however, no difference between treatments was evident at any of the measured time points (all P > 0.05). Therefore, consumption of a low dose of alcohol after damaging exercise appears to have no effect on the loss of force associated with strenuous eccentric exercise. PMID:20878178

Barnes, Matthew J; Mündel, Toby; Stannard, Stephen R

2010-09-28

186

Alpha-sarcoglycan deficiency featuring exercise intolerance and myoglobinuria.  

PubMed

An 8-year-old boy was referred for recent onset of easy fatigue. He showed hyperCKemia and mild scapular winging. Muscle biopsy on the quadriceps muscle demonstrated slight fibre size variability. Dystrophin was normally distributed, carnitine palmitoyl transferase and glycolytic enzymes had normal activities. In the following years the patient developed exercise intolerance and myoglobinuria. Immunohistochemistry showed marked reduction of alpha-sarcoglycan, confirmed by Western blotting. Molecular analysis revealed compound heterozygosity with Arg284Cys and Glu137Lys substitutions, corresponding to nucleotide changes C850 T and G409 A in the gene. At present the patient, 20 years old, shows mild proximal weakness with prominent involvement of the paraspinal muscles, dorsal kyphosis and lumbar hyperlordosis. Exercise intolerance and myoglobinuria, already described in Becker muscular dystrophy, should be also considered among the possible presentations of sarcoglycan deficiencies. PMID:12075495

Mongini, T; Doriguzzi, C; Bosone, I; Chiadò-Piat, L; Hoffman, E P; Palmucci, L

2002-04-01

187

Muscle strengthening and physical conditioning to reduce impairment and disability in chronic stroke survivors  

Microsoft Academic Search

Objective: To evaluate the impact of a program of muscle strengthening and physical conditioning on impairment and disability in chronic stroke subjects.Design: A randomized pretest and posttest control group, followed by a single-group pretest and posttest design.Subjects: Thirteen community-dwelling stroke survivors of at least 9 months.Intervention: A 10-week (3 days\\/week) program consisting of a warm-up, aerobic exercises, lower extremity muscle

Luci Fuscaldi Teixeira-Salmela; Sandra Jean Olney; Sylvie Nadeau; Brenda Brouwer

1999-01-01

188

Effect of regular exercise on health and disease.  

PubMed

It is known for a long time that exercise increases physical adequacy, has beneficial effects on the general health condition as well as a playing preventing role against various disease states. To decrease the risk of disease and maintain good health, the natural defense system of the organism needs to be strengthened. It is thought that in addition to increasing the body's resistance to disease through the strengthening of the immune system, decreases the convalescence time, increases work efficiency and improves the sportive performance of the individual all which would contribute positively to the national economy. The positive effects of regular exercising of aerobic nature such as strengthening of the immune system, protection against diseases as well as its positive effects on quality of life will help to emphasize the importance of physical exercise and improve the general view of sports by society. PMID:16264392

Karacabey, Kursat

2005-10-01

189

Comparison of Lower Body Specific Resistance Training on the Hamstring to Quadriceps Strength Ratios in Men and Women  

ERIC Educational Resources Information Center

In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional…

Dorgo, Sandor; Edupuganti, Pradeep; Smith, Darla R.; Ortiz, Melchor

2012-01-01

190

Dynamic control and conventional strength ratios of the quadriceps and hamstrings in subjects with anterior cruciate ligament deficiency  

Microsoft Academic Search

The hamstrings:quadriceps muscle strength ratio has been used as an indicator of normal balance between the knee flexors and extensors. A more functional approach to this strength ratio would be to compare opposite muscle actions of antagonistic muscle groups. The dynamic strength control ratio (DSCR) should give a more appropriate measure relating to knee function. There is a lack of

C. D. Hole; G. H. Smith; J. Hammond; A. Kumar; J. Saxton; T. Cochrane

2000-01-01

191

Eccentric and concentric isokinetic moment characteristics in the quadriceps and hamstrings of the chronic isolated posterior cruciate ligament injured knee  

Microsoft Academic Search

OBJECTIVE: Functional strength deficits associated with chronic isolated posterior cruciate ligament (PCL) insufficiency have received limited attention in the literature. The purpose of this study was to determine the eccentric and concentric isokinetic moment characteristics of the quadriceps and hamstrings in a sample of patients with isolated PCL injury. METHODS: Eccentric and concentric mean average and average peak moments were

C. L. MacLean; J. E. Taunton; D. B. Clement; W. Regan

1999-01-01

192

Effect of a Periodized Power Training Program on the Functional Performances and Contractile Properties of the Quadriceps in Sprinters  

ERIC Educational Resources Information Center

Our purpose was to compare the effect of a periodized preparation consisting of power endurance training and high-intensity power training on the contractile properties of the quadriceps muscle and functional performances in well trained male sprinters (n = 7). After 4 weeks of high-intensity power training, 60-m sprint running time improved by an…

Kamandulis, Sigitas; Skurvydas, Albertas; Brazaitis, Marius; Stanislovaitis, Aleksas; Duchateau, Jacques; Stanislovaitiene, Jurate

2012-01-01

193

Running injuries and hamstring and quadriceps weakness and balance: A case?control study in male runners  

Microsoft Academic Search

This is a case?control study on the relationship between strength of the hamstrings and quadriceps muscle and running injuries. Sixteen male runners, who had sustained a medically treated running injury during the year prior to this study, were matched for weekly running distance and age with 16 male noninjured control runners. All subjects were fit at the time of measurement.

Willem Van Mechelen; Hynek Hlobil; Martin H. G. Rep; Wico Strobos; Han C. G. Kemper

1994-01-01

194

Effect of a Periodized Power Training Program on the Functional Performances and Contractile Properties of the Quadriceps in Sprinters  

ERIC Educational Resources Information Center

|Our purpose was to compare the effect of a periodized preparation consisting of power endurance training and high-intensity power training on the contractile properties of the quadriceps muscle and functional performances in well trained male sprinters (n = 7). After 4 weeks of high-intensity power training, 60-m sprint running time improved by…

Kamandulis, Sigitas; Skurvydas, Albertas; Brazaitis, Marius; Stanislovaitis, Aleksas; Duchateau, Jacques; Stanislovaitiene, Jurate

2012-01-01

195

Comparison of Lower Body Specific Resistance Training on the Hamstring to Quadriceps Strength Ratios in Men and Women  

ERIC Educational Resources Information Center

|In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional…

Dorgo, Sandor; Edupuganti, Pradeep; Smith, Darla R.; Ortiz, Melchor

2012-01-01

196

Seismological Exercises  

NSDL National Science Digital Library

This homework exercise, which was designed for an undergraduate level geology class at Tulane University, asks the student to make evaluations about the Loma Prieta Earthquake and other earthquakes using seismograms, time travel curves, maps and other information.

Nelson, Stephen

197

Compulsive Exercise  

MedlinePLUS

... diets, and for some, this may develop into eating disorders such as anorexia and bulimia. And some people ... exercise, especially when it is combined with an eating disorder, can cause serious and permanent health problems, and ...

198

Clinical outcomes after repair of quadriceps tendon rupture: a systematic review.  

PubMed

The existing evidence regarding the management of quadriceps tendon rupture remains obscure. The aim of the current review is to investigate the characteristics, the different techniques employed and to analyse the clinical outcomes following surgical repair of quadriceps tendon rupture. An Internet based search of the English literature of the last 25 years was carried out. Case reports and non-clinical studies were excluded. The methodological quality of the included studies was assessed using the Coleman Methodology Score. All data regarding mechanism and site of rupture, type of treatment, time elapsed between diagnosis and repair, patients' satisfaction, clinical outcome, return to pre-injury activities, complications and recurrence rates were extracted and analysed. Out of 474 studies identified, 12 met the inclusion criteria. The average of Coleman Methodology Score was 50.46/100. In total 319 patients were analysed with a mean age of 57 years (16-85). The mean time of follow-up was 47.5 months (3 months to 24 years). The most common mechanism of injury was simple fall (61.5%). Spontaneous ruptures were reported in 3.2% of cases. The most common sites of tear were noted between 1cm and 2 cm of the superior pole of the patella and, in the older people, at the osseotendinous junction. The most frequently used repair technique was patella drill holes (50% of patients). Simple sutures were used in mid-substance ruptures. Several reinforcement techniques were employed in case of poor quality or retraction of the torn ends of tendon. The affected limb was immobilised in a cast for a period of 3-10 weeks. Quadriceps muscular atrophy and muscle strength deficit were present in most of the cases. Worst results were noted in delayed repairs. Reported complications included heterotopic ossifications in 6.9% of patients, deep venous thrombosis or pulmonary embolism in 2.5%, superficial infection in 1.2% and deep infection in 1.1%. It appears that the type of surgical repair does not influence the clinical results. The majority of the studies reported good or excellent ROM and return to the pre-injury activities. The overall rate of re-rupture was 2%. PMID:22959496

Ciriello, Vincenzo; Gudipati, Suribabu; Tosounidis, Theodoros; Soucacos, P N; Giannoudis, Peter V

2012-09-07

199

Adaptations to high-intensity intermittent exercise in rodents  

PubMed Central

In humans, exercise-induced plasma volume (PV) expansion is typically associated with an increase in plasma albumin content, due in part to an increase in hepatic albumin synthesis. We tested the ability of a 12-day high-intensity intermittent exercise protocol to induce an increase in PV in rodents. Since albumin synthesis is transcriptionally regulated, we tested the hypothesis that exercise training would induce an increase in hepatic albumin gene expression. Fifty adult male Sprague-Dawley rats weighing between 245 and 350 g were randomly assigned to one of five groups: cage control (CC), sham exercise (sham), continuous moderate-intensity exercise training (MI), high-intensity intermittent exercise training (HI), or a single day of HI training (1-HI). Twenty-four hours after the last training session, rats were anesthetized. PV was determined, and the liver was removed, flash frozen, and stored for later analysis. Citrate synthase (CS) activity of the red quadriceps muscle, a marker of aerobic adaptation, increased with training (MI and HI) and in response to 1-HI (P < 0.05). We did not see a significant exercise-induced PV expansion as PV averaged 23.6 ± 2.7 ml/kg body wt in the CC group and 26.6 ± 1.3 ml/kg body wt in the HI group (P > 0.05). However, hepatic albumin mRNA expression, as determined by real-time PCR, increased 2.9 ± 0.4- and 4.1 ± 0.4-fold after MI and HI, respectively, compared with CC. A single bout of HI (1-HI) did not alter hepatic albumin mRNA expression. These data demonstrate an increase in both CS activity and hepatic albumin gene expression with 12 days of aerobic exercise training in the rodent with a rapid (within 24 h) adaptation in the skeletal muscle to high-intensity intermittent exercise.

Bexfield, Nathan A.; Parcell, Allen C.; Nelson, W. Bradley; Foote, Kristopher M.; Mack, Gary W.

2009-01-01

200

Bonds that strengthen under force  

NASA Astrophysics Data System (ADS)

While the adhesive strength of most receptor-ligand interactions is exponentially reduced if strained, some receptor-ligand complexes exist that strengthen under force which is the hallmark of catch bonds. Although the existence of catch bonds was theoretically predicted, the first experimental demonstrations of their existence were given only recently, i.e. for the bacterial adhesin FimH that is located at the tip of type I fimbriae of E. coli and for p-selectin. In a major collaborative effort, we studied the structural origin by which the FimH-mannose bond is switched by force to a high binding state. Mutational studies were thereby combined with steered molecular dynamic simulations to decipher how force might affect protein conformation. Force-activation of FimH leads to a complex `stick-and-roll' bacterial adhesion behavior in which E. coli preferentially rolls over mannosylated surfaces at low shear but increasingly sticks firmly as the shear is increased. Interesting similarities are further seen if comparing the structural mechanisms by which liganded FimH and liganded integrins are switched to a high binding state. This comparison was made possible by docking fibronectin's 10^th type III module (fnIII10) to ?V?3 integrin. ?V?3 can switch from the ``closed'' ?V?3 integrin headpiece to the ``open'' conformation by opening the hinge angle between the ?A domain and the hybrid domain of the ?-integrin. The ``open'' state has been implicated by many experimental laboratories to correspond to the activated state of integrins. W. E. Thomas, E. Trintchina, M. Forero, V. Vogel, E. Sokurenko, Bacterial adhesion to target cells enhanced by shear-force, Cell, 109 (2002) 913. W. E. Thomas, L. M. Nilsson, M. Forero, E. V. Sokurenko, V. Vogel, Shear-dependent `stick-and-roll' adhesion of type 1 fimbriated Escherichia coli, Molecular Microbiology 53 (2004) 1545. W. Thomas, M. Forero, O. Yakovenko, L. Nilsson, P. Vicini, E. Sokurenko, V. Vogel, Catch Bond Model Derived from Allostery Explains Force-Activated Bacterial Adhesion, Biophys. J, in press E. Puklin-Faucher, M. Gao, K. Schulten, V. Vogel, How the opening of the ?A/hybrid domain hinge angle in the ?v?3 integrin headpiece is regulated by the liganded MIDAS conformation and by ligand-mediated mechanical force, submitted.

Vogel, Viola

2006-03-01

201

MuRF-1 and Atrogin-1 Protein Expression and Quadriceps Fiber Size and Muscle Mass in Stable Patients with COPD.  

PubMed

Abstract Introduction: Animal studies demonstrate the importance of the E3 ubiquitin ligases, Muscle RING-Finger Protein 1 (MuRF-1) and atrogin-1, in muscle protein degradation during acute muscle atrophy. Small clinical studies suggest MuRF-1 and atrogin-1 expression in the quadriceps muscle is also increased in stable patients with Chronic Obstructive Pulmonary Disease compared to controls. However, it remains unclear whether these ligases have a role in maintaining a muscle-wasted state in COPD patients. Methods: 32 stable COPD patients (16 with a low fat-free mass index (FFMI), 16 with a normal FFMI) and 15 controls underwent lung function and quadriceps strength tests and a percutaneous quadriceps biopsy. Quadriceps MuRF-1 and atrogin-1 protein were quantified with western blotting. Quadriceps fiber cross-sectional area (CSA) and fiber proportions were determined by immunohistochemistry on muscle sections. MuRF-1 and atrogin-1 levels were compared between COPD patients with and without a low FFMI, and between patients and controls, and correlations between MuRF-1 and atrogin-1 levels and quadriceps fiber CSA in the patients were investigated. Results: Atrogin-1 protein levels were lower in patients than controls, but similar in patients with a low and normal FFMI. MuRF-1 levels did not differ between any groups. MuRF-1 and atrogin-1 levels were not associated with quadriceps fiber CSA or quadriceps strength in patients. Conclusions: Chronic upregulation of ubiquitin ligases was not evident in the quadriceps muscle of stable COPD patients with a low muscle mass. This does not exclude the possibility of transient increases in ubiquitin ligases during acute catabolic episodes. PMID:23844868

Natanek, Samantha A; Riddoch-Contreras, Joanna; Marsh, Gemma S; Hopkinson, Nicholas S; Moxham, John; Man, William D-C; Kemp, Paul R; Polkey, Michael I

2013-07-11

202

Development of a Dispersion-Strengthened Superalloy.  

National Technical Information Service (NTIS)

Two methods were compared for preparing oxide-dispersion-strengthened superalloys. Alloy powders containing dispersed oxides were prepared by the selective reduction of spray-dried mixtures and also by vapor deposition of matrix metal onto dispersoid part...

R. F. Cheney W. Scheithauer

1967-01-01

203

Manufacturing Methods for Dispersion Strengthened Copper.  

National Technical Information Service (NTIS)

Oxide-strengthened copper forms were processed from powders prepared by spray drying, calcining, and selective hydrogen reduction. The powders were compacted, sintered, and hot consolidated. Two major problems were encountered in the preparation of consol...

N. E. Kopatz W. Scheithauer R. F. Cheney

1970-01-01

204

Strengthening mechanisms of tungsten powder reinforced uranium  

SciTech Connect

Tungsten powder reinforced uranium exhibits a three-fold increase in yield strength due to precipitation hardening. The tungsten-rich interphase precipitates form at moving phase boundaries during slow cooling. Further increases in yield strength, attained with increasing tungsten content, are due to composite strengthening; this is verified by increasing elastic modulus with increasing tungsten content. Age hardening behavior is observed, with strengthening occurring at aging temperatures low in the alpha phase. Aging higher in alpha gives initial strengthening followed by rapid overaging. Beta phase aging results in a very soft structure with precipitates visible optically. Wrought material exhibits significant strain hardening as well as composite strengthening due to elongation of the tungsten particles. 7 refs., 15 figs., 4 tabs.

Lewis, M.A.K.; Hill, M.A.; Rollett, A.D.; Dunn, P.S.; Mortensen, A. (Los Alamos National Lab., NM (USA); Massachusetts Inst. of Tech., Cambridge, MA (USA))

1989-01-01

205

Do Twin Boundaries Always Strengthen Metal Nanowires?  

PubMed Central

It has been widely reported that twin boundaries strengthen nanowires regardless of their morphology—that is, the strength of nanowires goes up as twin spacing goes down. This article shows that twin boundaries do not always strengthen nanowires. Using classical molecular dynamics simulations, the authors show that whether twin boundaries strengthen nanowires depends on the necessary stress for dislocation nucleation, which in turn depends on surface morphologies. When nanowires are circular cylindrical, the necessary stress of dislocation nucleation is high and the presence of twin boundaries lowers this stress; twin boundaries soften nanowires. In contrast, when nanowires are square cylindrical, the necessary stress of dislocation nucleation is low, and a higher stress is required for dislocations to penetrate twin boundaries; they strengthen nanowires.

2009-01-01

206

Dispersion Strengthening of Lead by Coprecipitation.  

National Technical Information Service (NTIS)

The report describes a method of dispersion strengthening lead using the coprecipitation method. Reagent grade chemicals were reacted to precipitate lead and aluminum compounds which were roasted to oxides and hydrogen reduced to form mixtures of lead pow...

D. H. Desy M. M. Tilman R. L. Crosby

1971-01-01

207

Do exercise motives predict obligatory exercise?  

PubMed

Few studies have examined whether factors predicting obligatory exercise differ by gender. 303 participants completed the Obligatory Exercise Questionnaire and the Reason for Exercise Inventory. All variables correlated significantly. However, the correlation between exercising for fitness and obligatory exercise was significantly stronger in women than men. In women, obligatory exercise was predicted by exercising to improve body tone, fitness, and to enhance mood; in men, obligatory exercise was predicted by exercising to improve body tone, enjoyment, and perceived attractiveness. Implications for treatment are discussed. PMID:22365798

Pritchard, Mary E; Beaver, Jessica L

2011-11-26

208

Trunk muscle action compensates for reduced quadriceps force during walking after total knee arthroplasty.  

PubMed

Patients with total knee arthroplasty (TKA) frequently exhibit changes in gait biomechanics post-surgery, including decreased ranges of joint motion and changes in joint loading; however, the actions of the lower-limb muscles in generating joint moments and accelerating the center of mass (COM) during walking are yet to be described. The aim of the present study was to evaluate differences in lower-limb joint kinematics, muscle-generated joint moments, and muscle contributions to COM accelerations in TKA patients and healthy age-matched controls when both groups walk at the same speed. Each TKA patient was fitted with a posterior-stabilized total knee replacement and underwent patellar resurfacing. Three-dimensional gait analysis and subject-specific musculoskeletal modeling were used to determine lower-limb and trunk muscle forces and muscle contributions to COM accelerations during the stance phase of gait. The TKA patients exhibited a 'quadriceps avoidance' gait pattern, with the vasti contributing significantly less to the extension moment developed about the knee during early stance (p=0.036). There was a significant decrease in the contribution of the vasti to the vertical acceleration (support) (p=0.022) and forward deceleration of the COM (braking) (p=0.049) during early stance; however, the TKA patients compensated for this deficiency by leaning their trunks forward. This significantly increased the contribution of the contralateral back extensor muscle (erector spinae) to support (p=0.030), and that of the contralateral back rotators (internal and external obliques) to braking (p=0.004). These findings provide insight into the biomechanical causes of post-operative gait adaptations such as 'quadriceps avoidance' observed in TKA patients. PMID:23206902

Li, Katherine; Ackland, David C; McClelland, Jodie A; Webster, Kate E; Feller, Julian A; de Steiger, Richard; Pandy, Marcus G

2012-12-01

209

Low frequency fatigue in human quadriceps is fatigue dependent and not task dependent.  

PubMed

It is well accepted that a low intensity/long duration isometric contraction induces more low frequency fatigue (LFF) compared to a high-intensity/short-duration contraction. However, previous reports examined the intensity/duration of the contraction but did not control the level of fatigue when concluding fatigue is task dependent. The purpose of this study was to determine whether a long duration/low intensity fatiguing contraction would induce greater LFF than a short duration/high-intensity contraction when the quadriceps muscle was fatigued to similar levels. Eighteen healthy male subjects performed quadriceps contractions sustained at 35% and 65% of maximal voluntary contraction (MVC) on separate days, until the tasks induced a similar amount of fatigue (force generating capacity=45% MVC). Double pulse torque to single pulse torque ratio (D/S ratio) was obtained before, immediately and 5min after fatigue along with the electromyographic (EMG) signal from vastus medialis (VM) and rectus femoris (RF). The D/S ratio significantly (p<0.05) increased by 8.7+/-8.5% (mean+/-SD) and 10.2+/-9.2% after 35% and 65% tasks, respectively, and remained elevated 5min into recovery; however, there was no significant difference in ratio between the two sessions immediately or 5min post-fatigue (p>0.05) even though the endurance time for the 35% fatigue task (124+/-39.68s) was significantly longer (p=0.05) than that of the 65% task (63+/-17.73s). EMG amplitude and median power frequency (MPF) analysis also did not reveal any significant differences between these two sessions after fatigue. These findings indicate that LFF fatigue is fatigue dependent as well as task intensity/duration dependent. These findings assist us in understanding task dependency and muscle fatigue. PMID:17157533

Iguchi, Masaki; Baldwin, Kris; Boeyink, Charles; Engle, Carol; Kehoe, Michael; Ganju, Anish; Messaros, Andrew J; Shields, Richard K

2006-12-08

210

An Artificial Tendon to Connect the Quadriceps Muscle to the Tibia  

PubMed Central

No permanent, reliable artificial tendon exists clinically. Our group developed the OrthoCoupler™ device as a versatile connector, fixed at one end to a muscle, and adaptable at the other end to inert implants such as prosthetic bones or to bone anchors. The objective of this study was to evaluate four configurations of the device to replace the extensor mechanism of the knee in goats. Within muscle, the four groups had: (A) needle-drawn uncoated bundles, (B) needle-drawn coated bundles, (C) barbed uncoated bundles, and (D) barbed coated bundles. The quadriceps tendon, patella, and patellar tendon were removed from the right hind limb in 24 goats. The four groups (n=6 for each) were randomly assigned to connect the quadriceps muscle to the tibia (with a bone plate). Specimens were collected from each operated leg and contralateral unoperated controls both for mechanical testing and histology at 90 days post-surgery. In strength testing, maximum forces in the operated leg (vs. unoperated control) were 1288±123 N (vs. 1387±118 N) for group A, 1323±144 N (vs. 1396±779 N) for group B, 930±125 N (vs. 1337±126 N) for group C, and 968±109 N (vs. 1528±146 N) for group D (mean ± SEM). The strengths of the OrthoCoupler™ legs in the needled device groups were equivalent to unoperated controls (p=0.6), while both barbed device groups had maximum forces significantly lower than their controls (p=0.001). We believe this technology will yield improved procedures for clinical challenges in orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.

Melvin, Alan; Litsky, Alan; Mayerson, Joel; Stringer, Keith; Melvin, David; Juncosa-Melvin, Natalia

2011-01-01

211

Peripheral fatigue limits endurance exercise via a sensory feedback-mediated reduction in spinal motoneuronal output.  

PubMed

This study sought to determine whether afferent feedback associated with peripheral muscle fatigue inhibits central motor drive (CMD) and thereby limits endurance exercise performance. On two separate days, eight men performed constant-load, single-leg knee extensor exercise to exhaustion (85% of peak power) with each leg (Leg1 and Leg2). On another day, the performance test was repeated with one leg (Leg1) and consecutively (within 10 s) with the other/contralateral leg (Leg2-post). Exercise-induced quadriceps fatigue was assessed by reductions in potentiated quadriceps twitch-force from pre- to postexercise (?Qtw,pot) in response to supramaximal magnetic femoral nerve stimulation. The output from spinal motoneurons, estimated from quadriceps electromyography (iEMG), was used to reflect changes in CMD. Rating of perceived exertion (RPE) was recorded during exercise. Time to exhaustion (?9.3 min) and exercise-induced ?Qtw,pot (?51%) were similar in Leg1 and Leg2 (P > 0.5). In the consecutive leg trial, endurance performance of the first leg was similar to that observed during the initial trial (?9.3 min; P = 0.8); however, time to exhaustion of the consecutively exercising contralateral leg (Leg2-post) was shorter than the initial Leg2 trial (4.7 ± 0.6 vs. 9.2 ± 0.4 min; P < 0.01). Additionally, ?Qtw,pot following Leg2-post was less than Leg2 (33 ± 3 vs 52 ± 3%; P < 0.01). Although the slope of iEMG was similar during Leg2 and Leg2-post, end-exercise iEMG following Leg2-post was 26% lower compared with Leg2 (P < 0.05). Despite a similar rate of rise, RPE was consistently ?28% higher throughout Leg2-post vs. Leg2 (P < 0.05). In conclusion, this study provides evidence that peripheral fatigue and associated afferent feedback limits the development of peripheral fatigue and compromises endurance exercise performance by inhibiting CMD. PMID:23722705

Amann, Markus; Venturelli, Massimo; Ives, Stephen J; McDaniel, John; Layec, Gwenael; Rossman, Matthew J; Richardson, Russell S

2013-05-30

212

Kegel Exercise Tips  

MedlinePLUS

... to know about Bladder Control for Women Kegel Exercise Tips What are Kegel exercises? To do Kegel exercises, you just squeeze your ... help with your bladder control. How do you exercise your pelvic muscles? Find the right muscles. Try ...

213

The effects of hip muscle strengthening on knee load, pain, and function in people with knee osteoarthritis: a protocol for a randomised, single-blind controlled trial  

PubMed Central

Background Lower limb strengthening exercises are an important component of the treatment for knee osteoarthritis (OA). Strengthening the hip abductor and adductor muscles may influence joint loading and/or OA-related symptoms, but no study has evaluated these hypotheses directly. The aim of this randomised, single-blind controlled trial is to determine whether hip abductor and adductor muscle strengthening can reduce knee load and improve pain and physical function in people with medial compartment knee OA. Methods/Design 88 participants with painful, radiographically confirmed medial compartment knee OA and varus alignment will be recruited from the community and randomly allocated to a hip strengthening or control group using concealed allocation stratified by disease severity. The hip strengthening group will perform 6 exercises to strengthen the hip abductor and adductor muscles at home 5 times per week for 12 weeks. They will consult with a physiotherapist on 7 occasions to be taught the exercises and progress exercise resistance. The control group will be requested to continue with their usual care. Blinded follow up assessment will be conducted at 12 weeks after randomisation. The primary outcome measure is the change in the peak external knee adduction moment measured during walking. Questionnaires will assess changes in pain and physical function as well as overall perceived rating of change. An intention-to-treat analysis will be performed using linear regression modelling and adjusting for baseline outcome values and other demographic characteristics. Discussion Results from this trial will contribute to the evidence regarding the effect of hip strengthening on knee loads and symptoms in people with medial compartment knee OA. If shown to reduce the knee adduction moment, hip strengthening has the potential to slow disease progression. Trial Registration Australia New Zealand Clinical Trials Registry ACTR12607000001493

Bennell, Kim L; Hunt, Michael A; Wrigley, Tim V; Hunter, David J; Hinman, Rana S

2007-01-01

214

Effects of prior exercise on oxygen uptake and phosphocreatine kinetics during high-intensity knee-extension exercise in humans  

PubMed Central

A prior bout of high-intensity square-wave exercise can increase the temporal adaptation of pulmonary oxygen uptake () to a subsequent bout of high-intensity exercise. The mechanisms controlling this adaptation, however, are poorly understood. We therefore determined the dynamics of intramuscular [phosphocreatine] ([PCr]) simultaneously with those of in seven males who performed two consecutive bouts of high-intensity square-wave, knee-extensor exercise in the prone position for 6 min with a 6 min rest interval. A magnetic resonance spectroscopy (MRS) transmit-receive surface coil under the quadriceps muscle allowed estimation of [PCr]; was measured breath-by-breath using a custom-designed turbine and a mass spectrometer system. The kinetics of the second exercise bout were altered compared with the first such that (a) not only was the instantaneous rate of change (at a given level of ) greater but the phase II ? was also reduced – averaging 46.6 ± 6.0 s (bout 1) and 40.7 ± 8.4 s (bout 2) (mean ± s.d.) and (b) the magnitude of the later slow component was reduced. This was associated with a reduction of, on average, 16.1 % in the total exercise-induced [PCr] decrement over the 6 min of the exercise, of which 4.0 % was due to a reduction in the slow component of [PCr]. There was no discernable alteration in the initial rate of [PCr] change. The prior exercise, therefore, changed the multi-compartment behaviour towards that of functionally first-order dynamics. These observations demonstrate that the responses relative to the work rate input for high-intensity exercise are non-linear, as are, it appears, the putative phosphate-linked controllers for which [PCr] serves as a surrogate.

Rossiter, H B; Ward, S A; Kowalchuk, J M; Howe, F A; Griffiths, J R; Whipp, B J

2001-01-01

215

Exercise for fitness does not decrease the muscular inactivity time during normal daily life.  

PubMed

The time spent in sedentary behaviors has been shown to be independent of exercise in epidemiological studies. We examined within an individual whether exercise alters the time of muscular inactivity within his/her normal daily life. Quadriceps and hamstring muscle electromyographic activities and heart rate were measured during 1 to 6 days of normal daily living of ordinary people. Of 84 volunteers measured, 27 (15 men, 12 women, 40.7 years?±?16.5 years) fulfilled the criteria of having at least 1 day with and 1 day without exercise for fitness (total of 87 days analyzed, 13.0?h?±?2.5?h/day). Reported exercises varied from Nordic walking to strength training and ball games lasting 30?min-150?min (mean 83?min?±?30?min). Exercise increased the time spent at moderate-to-vigorous muscle activity (6%?±?4% to 9%?±?6%, P?exercise (not significant). Duration of exercise correlated positively to the increase in moderate-to-vigorous muscle activity time (r?=?0.312, P?exercise for fitness, regardless of its duration, does not decrease the inactivity time during normal daily life. This is possible by slight modifications in daily nonexercise activities. PMID:22417280

Finni, T; Haakana, P; Pesola, A J; Pullinen, T

2012-03-15

216

Stimulated and voluntary fatiguing contractions of quadriceps femoris differently disturb postural control  

Microsoft Academic Search

Muscle fatigue affects muscle strength and postural control. However, it is not known whether impaired postural control after fatiguing muscular exercise depends on the nature of the muscle contraction. To answer this question, the present study analyzes changes in postural control after two fatiguing exercises of equal duration and intensity but that induced different magnitudes of strength loss. The effects

Thierry Paillard; Julien Maitre; Vincent Chaubet; Liliane Borel

2010-01-01

217

Extraversion and Exercise Addiction  

Microsoft Academic Search

Extraversion has been suggested as a factor associated with addiction. This claim was tested in relation to exercise addiction. Twelve exercise addicts were compared with 12 nonaddicted individuals who were committed to regular exercise and with 12 nonexercising individuals drawn from the same student population. Addicted exercisers did not differ from nonaddicted exercisers in extraversion, although exercisers as a group

Sarah Mathers; Michael B. Walker

1999-01-01

218

Interval training guidance system with music and wireless group exercise motivations  

Microsoft Academic Search

Interval training is a well known exercise protocol which helps strengthen and improve one's cardiovascular fitness. It interleaves high intensity exercises with rest periods. Despite the known benefits, proper scheduling and completion of interval training routines are not easy to perform. For example, without expensive equipment such as a treadmill, there is almost no way to figure out one's speed

Myung-kyung Suh; Kyujoong Lee; Ani Nahapetian; Majid Sarrafzadeh

2009-01-01

219

Flooding Exercises  

NSDL National Science Digital Library

This homework exercise, developed for an undergraduate geology course at Tulane University, leads students through the steps involved in determining the probability that a flood of a given discharge will occur in any given year. Students retrieve discharge data from U.S. Geological Services Internet sites for Dry Creek, LA, Rapid Creek, SD and Red River, ND to make their calculations.

Nelson, Stephen

220

Noninvasive detection of change in skeletal muscle oxygenation during incremental exercise with near-infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Near infrared spectroscopy (NIRS) has been developed as a non-invasive method to assess O2 delivery, O2 consumption and blood flow, in diverse local muscle groups at rest and during exercise. The aim of this study was to investigate local O2 consumption in exercising muscle by use of near-infrared spectroscopy (NIRS). Ten elite athletes of different sport items were tested in rest and during step incremental load exercise. Local variations of quadriceps muscles were investigated with our wireless NIRS blood oxygen monitor system. The results show that the changes of blood oxygen relate on the sport items, type of muscle, kinetic capacity et al. These results indicate that NIRS is a potential useful tool to detect local muscle oxygenation and blood flow profiles; therefore it might be easily applied for evaluating the effect of athletes training.

Liu, Fang; Luo, Qingming; Xu, Guodong; Li, Pengcheng

2003-12-01

221

Reconstruction of quadriceps tendon with Achilles tendon allograft in older children with congenital dislocation of the knee.  

PubMed

This is a case report of two children with congenital dislocation of the knee. They have been treated surgically with Z-lengthening of the quadriceps tendon and additional reconstruction of the quadriceps tendon with Achilles tendon allograft to fill in the remaining average 6 cm gap of the tendon. The patients were two girls, 6 and 9 years old. One of them had an operative treatment previously with a tendon lengthening procedure and it was failed and the other patient was untreated before. Preoperatively, untreated case was unable to walk. The other patient was limping. None of them was able to flex their knees beyond the neutral extension position. Postoperatively, both patients were able to walk and the knees were reduced to a range of motion of 0 degrees -95 degrees of flexion. The mean follow-up time was 20 months. PMID:16758235

Söyüncü, Yetkin; Mihçi, Ercan; Ozcanli, Haluk; Ozenci, Merter; Akyildiz, Feyyaz; Aydin, A Turan

2006-06-07

222

Comparison of lower body specific resistance training on the hamstring to quadriceps strength ratios in men and women.  

PubMed

In this study, we compared hamstring (H) and quadriceps (Q) strength changes in men and women, as well as changes in conventional and functional H:Q ratios following an identical 12-week resistance training program. An isokinetic dynamometer was used to assess 14 male and 14 female participants before and after the intervention, and conventional and functional H:Q ratios were calculated. Hamstring strength improved similarly in men and women, but improvement in quadriceps strength was significantly greater in men, while women showed only modest improvements. For the conventional and functional H:Q ratios, women showed significantly greater improvements than men. Both men and women were able to exceed the commonly recommended 0.6 conventional and 1.0 functional H:Q ratios after the 12-week lower-body resistance training program. PMID:22808699

Dorgo, Sandor; Edupuganti, Pradeep; Smith, Darla R; Ortiz, Melchor

2012-06-01

223

Treatment of Knee Arthrofibrosis and Quadriceps Insufficiency after Patellar Tendon Repair: A Case Report Including Use of the Graston Technique  

PubMed Central

Arthrofibrosis of the knee is a surgical complication that can limit range of motion, inhibit muscle activity, and decrease patient function. Optimal conservative treatment has not been well established in the literature, leaving a clinician with limited evidence for treatment planning. Described here is part of the rehabilitative course of care for a patient with arthrofibrotic limitations after a mid-substance patellar tendon repair with augmentation. Marked limitations in knee flexion range of motion and quadriceps activity were addressed using the Graston Technique to deal with soft-tissue adhesions; traditional physical therapy care was also provided. Clear improvement in range of motion and quadriceps activity and function was noted over the course of 5 treatments during 1 month. Treatment process and clinical reasoning are offered to promote understanding and to facilitate future inquiry.

Black, Douglass W.

2010-01-01

224

Adaptive control of functional neuromuscular stimulation-induced knee extension exercise.  

PubMed

An automated system for exercising the paralyzed quadriceps muscles of spinal cord injured patients using functional neuromuscular stimulation (FNS) has been developed. It induces smooth concentric and eccentric contractions in both limbs to enable bilateral 70 degree knee extensions in an asynchronous pattern. External load resistance is applied at the ankle level to "overload" the muscles and bring about training effects. The system uses adaptive control methods to adjust FNS current output (threshold level and the ramp slope) to the quadriceps muscles to maintain performance as the muscles fatigue. Feedback control signals for limb movement and knee extension angle are used to continuously adjust the FNS current parameters so that the external load is moved through the preset zero to 70 degree angle range. Typically, the threshold current level and the FNS current increase as the muscles fatigue to maintain performance with repetitive contractions. Fatigue is defined as the inability to extend the knee to 50 percent of the 70 degree target angle. When this occurs, FNS is automatically terminated for the fatigued leg, while the functioning leg continues to exercise. The automated nature of this system appears to be advantageous as compared to a manually operated system for subject safety, convenience, and uniformity of exercise bouts. Simulated safety problems, such as hyperextension of the knee joint, open circuitry, muscle spasms, and low battery power, were successfully detected by the logic circuitry, and the system followed appropriate safety procedures to minimize risk. PMID:1941644

Ezenwa, B N; Glaser, R M; Couch, W; Figoni, S F; Rodgers, M M

1991-01-01

225

Boron strengthening in FeAl  

SciTech Connect

The effect of boron on the strength of B2-structured FeAl is considered as a function of composition, grain size and temperature. Boron does not affect the concentrations of antisite atoms or vacancies present, with the former increasing and the latter decreasing with increasing deviation from the stoichiometric composition. When vacancies are absent, the strength increase per at. % B per unit lattice strain, {Delta}{sigma}/({Delta}c x {epsilon}) increases with increasing aluminum concentration, but when vacancies are present (>45 at. % Al), {Delta}{sigma}/({Delta}c x {epsilon}) decreases again. Boron increases grain size strengthening in FeAl. B strengthening is roughly independent of temperature up to the yield strength peak but above the point, when diffusion-assisted deformation occurs, boron strengthening increases dramatically.

Baker, I.; Li, X.; Xiao, H.; Klein, O.; Nelson, C. [Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering; Carleton, R.L.; George, E.P. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1998-11-01

226

Quadriceps strength, inter-extremity difference (IED) and joint status in adult persons with severe haemophilia in different age stages.  

PubMed

Quadriceps weakness seems to be a hallmark in adult persons with severe haemophilia (PWH). The purpose of this study was to compare PWH and non-haemophilic controls in different age stages with reference to joint status and quadriceps strength. Further aims were to examine the extent of strength-specific inter-extremity-difference (IED) and the prevalence of abnormal IED (AIED). A total of 106 adults with severe haemophilia (H) and 80 controls (C) had undergone an orthopaedic examination for classification of knee and ankle status using the WFH score. Quadriceps strength was evaluated unilaterally as well as bilaterally with a knee extensor device. Each group was divided into four age-related subgroups (HA/CA: 18-29, HB/CB: 30-39, HC/CC: 40-49, HD/CD: 50-70; in years). H presented a worse knee and ankle status than C indicated by higher WFH scores (P < 0.01). Regarding the age-matched subgroups only HB showed higher knee scores than CB (P < 0.05). The ankles were clinically more affected in HB-HD compared with those in age-matched controls (P < 0.05). H showed lower quadriceps strength than C (P < 0.05). In addition, all subgroups of H presented lower strength (HA: 10-17, HB: 19-23, HC: 35-36, HD: 53-61; in%, P < 0.05). IED was higher in H than in C [H: 12.0 (5.3/32.2) vs. C: 7.1 (2.9/10.9); Median (quartiles) in%, P < 0.001] and increased with age in H. We discovered an AIED in 35% of H. These findings highlight the importance for the early implementation of preventive and rehabilitative muscle training programmes in the comprehensive treatment of PWH. PMID:23051604

Brunner, A; Stäuber, F; Göhler, S; Czepa, D; Krüger, S; Wendel, M; Seuser, A; Hilberg, T

2012-10-11

227

M. Quadriceps femoris of Man, a muscle with an unusual enzyme activity pattern of energy supplying metabolism in mammals  

Microsoft Academic Search

1.The following enzyme activities were estimated in needle-biopsy samples of the lateral part of the human quadriceps femoris muscle: triosephosphate dehydrogenase (TPDH), lactate dehydrogenase (LDH), NAD: glycerol-3-phosphate dehydrogenase (GPDH), hexokinase (HK), NAD: malate dehydrogenase (MDH), citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase.2.Although the enzyme activities in muscle of women were lesser than in those of men, no difference was found in

Arno?t Bass; Karel Vondra; Ratmír Rath; Václav Vítek

1975-01-01

228

Effects of Supplemental Carbohydrate Ingestion During Superimposed Electromyostimulation Exercise in Elite Weight Lifters.  

PubMed

ABSTRACT: The purpose of this investigation was to test the effects of carbohydrate supplementation on blood parameters and force output during superimposed electromyostimulation (SEMS) single leg isometric contractions. We hypothesized that carbohydrate ingestion prior and during muscle contractions would lead to greater glucose availability and greater total force output for the session. Six elite resistance trained male subjects participated in a randomized, counterbalanced, double blind study. Subjects were randomly assigned to placebo (PL) or carbohydrate (CHO). Subjects in CHO consumed 1 g carbohydrate•kg body mass loading dose and 0.17 g carbohydrate•kg body mass every six min during exercise protocol. PL received an equal volume of a solution made of saccharin/aspartame. Exercise protocol consisted of repeated 20 s isometric contractions of quadriceps muscle at 50% maximal voluntary contraction followed by 40 s rest until failure occurred. Importantly, quadriceps maximal voluntary contraction with SEMS was performed in beginning and then every 5 min during the last 3 s of isometric contractions throughout the exercise protocol. Venous blood samples were taken pre-, immediately post-, and at 5 min post- exercise and analyzed for glucose, nonesterified fatty acids, and glycerol. Our results indicate that CHO ingestion increased (p < 0.05) plasma glucose, but no significant differences (p > 0.05) were detected for nonesterified fatty acids or glycerol. Importantly, total force output during exercise protocol was higher (p < 0.05) in CHO compared to PL. Therefore, our data suggest that CHO supplementation prior to and during exercise may be beneficial for individuals performing high-volume resistance training. PMID:23442284

Wax, Benjamin; Kavazis, Andreas N; Brown, Stanley P; Webb, Heather E

2013-02-25

229

Effect of a simulated soccer match on the functional hamstrings-to-quadriceps ratio in amateur female players.  

PubMed

The purpose of this study was to investigate the effect of a simulated soccer test on the functional hamstrings-to-quadriceps ratio (H(ecc) :?Q(con)) in female soccer players. Fourteen amateur players (age, 26.1?±?4.6 years; height, 168?±?12?cm; body mass, 62.7?±?5.5?kg; body fat, 23.7?±?2.2%) performed the modified Loughborough Intermittent Shuttle Test (modified LIST). Isokinetic strength assessments of the hamstrings and quadriceps on the dominant and non-dominant legs at 120°/s were performed before and immediately after the modified LIST. H(ecc) :?Q(con) was calculated as the ratio of the peak eccentric torque of the hamstrings to the peak concentric torque of the quadriceps. A two-way univariate analysis of variance was used to assess the effect of time and leg dominance on H(ecc)?:?Q(con). The main results showed that the modified LIST led to a significant decrease in H(ecc)?:?Q(con) in the dominant (-14.1%) and non-dominant legs (-8.0%) (P?=?0.02). However, this decrease was not significantly different between dominant and non-dominant legs (P?=?0.42). These results reflect a greater risk of hamstrings tears and ACL sprains at the end of soccer matches. PMID:22107131

Delextrat, A; Baker, J; Cohen, D D; Clarke, N D

2011-11-23

230

Effect of a high intensity quadriceps fatigue protocol on knee joint mechanics and muscle activation during gait in young adults.  

PubMed

The purpose of this study was to determine the effect of impaired quadriceps function on knee joint biomechanics and neuromuscular function during gait. Surface electromyograms, three-dimensional motion and ground reaction forces were collected during gait before and after 20 healthy adults completed a high intensity quadriceps fatigue protocol. Pattern recognition techniques were utilized to examine changes in amplitude and temporal characteristics of all gait variables. The fatigue protocol resulted in decreased knee extensor torque generation and quadriceps median power frequencies for 18 of 20 participants (p < 0.05). The gait data from these 18 participants was analyzed. The knee external rotation angle increased (p < 0.05), the net external flexion and external rotation moments decreased (p < 0.05), and the net external adduction moment increased (p < 0.05). Post-fatigue changes in periarticular muscle activation patterns were consistent with the biomechanical changes, but were not significantly altered. Even for this low demand task of walking the knee motion and loading characteristics were altered following a high intensity fatigue protocol in a manner that may place the knee joint at greater risk for joint pathology and injury. PMID:21573776

Murdock, Gillian Hatfield; Hubley-Kozey, Cheryl L

2011-05-15

231

Bone Mechanotransduction May Require Augmentation in Order to Strengthen the Senescent Skeleton  

PubMed Central

Physical exercise is thought to hold promise as a non-invasive countermeasure against skeletal fragility arising from post-menopausal and age-related osteoporosis. Importantly, mechanical loading and exercise are capable of increasing bone size via periosteal expansion, which by far, is the most effective means of strengthening the structure of a given bone. The focus of this review was to therefore explore whether exercise has the potential to increase periosteal modeling and bone size in the senescent skeleton. A survey of exercise trials in humans suggests that exercise interventions that enhance periosteal modeling in the young skeleton fail to do the same in the elderly skeleton. Underlying this ineffectiveness, in vitro studies indicate that aging lowers basal levels of cell function and degrades bone mechanotransduction at a variety of levels from altered second messenger signaling to gene expression driving proliferation and/or differentiation. Given these age-related alterations, the ultimate efficacy of an exercise intervention may depend upon concurrent supplementation that directly address deficits in signaling and/or cell function. In this context, in vivo animal models of mechanical loading that simulate the muted periosteal adaptation in the elderly hold potential to examine the efficacy of countermeasures. Preliminary in vivo experiments suggest that pharmacologically counteracting age-related deficits in cellular function can restore exercise induced periosteal modeling in the senescent skeleton to levels observed in young animals. If the safety and efficacy of this strategy were to be confirmed for human use, it would enable the utilization of exercise as a viable countermeasure against skeletal fragility at senescence.

Srinivasan, Sundar; Gross, Ted S.; Bain, Steven D.

2012-01-01

232

Glutathione homeostasis in response to exercise training and nutritional supplements  

Microsoft Academic Search

Glutathione plays a central role in the maintenance of tissue antioxidant defenses and in the regulation of redox sensitive signal transduction. In muscle cells, the level and redox status of GSH regulates activity of the redox sensitive transcription factor NF-?B. Physical exercise may cause oxidation of GSH in tissues such as the blood, skeletal muscle and liver. Endurance training strengthened

Chandan K. Sen

1999-01-01

233

Augmenting Exercise Systems with Virtual Exercise Environment  

Microsoft Academic Search

Adhering to an exercise program is a challenge for everybody who wants to build a healthier body and lifestyle through physical\\u000a exercise. We have developed an Virtual Exercise Environment (VEE) that augments stationary exercise equipment with virtual\\u000a reality techniques to make exercising more enjoyable. Our VEE system consists of a recording system to capture video, distance\\u000a and incline data about

Wei Xu; Jaeheon Jeong; Jane Mulligan

2009-01-01

234

Strengthening the K12 Teacher Workforce  

NSDL National Science Digital Library

Recent national reports, calling attention to the need to increase and enrich the nation's science and engineering talent pool, are placing an increased emphasis on expanding and strengthening the teacher workforce. This article offers information about and links to NSF initiatives in STEM teacher improvement and recruitment.

Prival, Joan

2007-10-24

235

Methods of Strengthening Existing Highway Bridges.  

National Technical Information Service (NTIS)

The report details the results of a study of the various methods of strengthening highway bridges. The initial task in the study was a thorough review of pertinent international literature to determine the methods currently being used and to discover inno...

F. W. Klaiber K. F. Dunker T. J. Wipf W. W. Sanders

1987-01-01

236

Strengthening 4-H Program Communication through Technology  

ERIC Educational Resources Information Center

|Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

Robideau, Kari; Santl, Karyn

2011-01-01

237

Strengthening Educational Leadership; The ISLLC Standards.  

ERIC Educational Resources Information Center

|Begun in 1994, the Interstate School Leaders Licensure Consortium operates under the aegis of the Council of Chief State School Officers and the National Policy Board for Educational Administration. ISLLC builds on research about skillful administrative leadership and emerging societal and educational perspectives. Standards will strengthen

Murphy, Joseph; Shipman, Neil; Pearlman, Mari

1997-01-01

238

Strengthening Family Practices for Latino Families  

ERIC Educational Resources Information Center

This study examined the effectiveness of a culturally adapted Strengthening Families Program (SFP) for Latinos to reduce risks for alcohol and drug use in children. Latino families, predominantly Puerto Rican, with a 9- to 12-year-old child and a parent(s) with a substance abuse problem participated in the study. Pre- and post-tests were conducted…

Chartier, Karen G.; Negroni, Lirio K.; Hesselbrock, Michie N.

2010-01-01

239

Strengthening 4-H Program Communication through Technology  

ERIC Educational Resources Information Center

Advances in technology are transforming how youth and parents interact with programs. The Strengthening 4-H Communication through Technology project was implemented in eight county 4-H programs in Northwest Minnesota. This article outlines the intentional process used to effectively implement technology in program planning. The project includes:…

Robideau, Kari; Santl, Karyn

2011-01-01

240

Strengthening the Nation by Narrowing the Gap  

ERIC Educational Resources Information Center

|A 2007 report by Jobs for the Future concluded that the United States "has miles to go to eliminate racial and ethnic disparities in degree production, strengthen the domestic workforce to meet demand for higher skills and knowledge, and remain internationally competitive." That the United States must educate more of its citizens for an…

Handel, Stephen; Montoya, James

2009-01-01

241

Strengthening Language Experiences for Children through Fingerplays.  

ERIC Educational Resources Information Center

|Fingerplays--brief stories that rhyme and can be dramatized by using the fingers--are an old activity for children that can be traced in Indian lore to a time before Columbus. Today, fingerplays delight and fascinate young children and provide a variety of learning opportunities. Fingerplays can provide a source for strengthening language…

Baker, Betty Ruth

242

Strengthening the Nation by Narrowing the Gap  

ERIC Educational Resources Information Center

A 2007 report by Jobs for the Future concluded that the United States "has miles to go to eliminate racial and ethnic disparities in degree production, strengthen the domestic workforce to meet demand for higher skills and knowledge, and remain internationally competitive." That the United States must educate more of its citizens for an…

Handel, Stephen; Montoya, James

2009-01-01

243

The impact of foot position on electromyographical activity of the superficial quadriceps muscles during leg extension.  

PubMed

This study investigated variations in electromyographic (EMG) responses of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) due to foot position during leg extension. Twenty-four men and women (23.67 +/= 4.02 years) performed 8 repetitions at 70% of 8 repetition maximum with their leg medially rotated, laterally rotated, and neutral. Repeated-measures analyses of variance indicated that the highest normalized root mean square (NrmsEMG) for the VM and VL occurred with medial rotation, and the highest NrmsEMG for the RF occurred with lateral rotation. Significant NrmsEMG increases and median power frequency decreases occurred across repetitions regardless of foot position. Therefore, medial rotation produced the greatest muscle activation for the VL and VM, whereas lateral rotation produced the greatest activation in the RF. These findings are applicable to athletes or bodybuilders who are seeking to selectively increase either the size or performance of a specific muscle of the quadriceps group. PMID:16437818

Stoutenberg, Mark; Pluchino, Alessandra P; Ma, Fangchao; Hoctor, Jennifer E; Signorile, Joseph F

2005-11-01

244

Creatine supplementation does not decrease oxidative stress and inflammation in skeletal muscle after eccentric exercise.  

PubMed

Thirty-six male rats were used; divided into 6 groups (n = 6): saline; creatine (Cr); eccentric exercise (EE) plus saline 24 h (saline + 24 h); eccentric exercise plus Cr 24 h (Cr + 24 h); eccentric exercise plus saline 48 h (saline + 48 h); and eccentric exercise plus Cr 48 h (Cr + 48 h). Cr supplementation was administered as a solution of 300 mg · kg body weight(-1) · day(-1) in 1 mL water, for two weeks, before the eccentric exercise. The animals were submitted to one downhill run session at 1.0 km · h(-1) until exhaustion. Twenty-four and forty-eight hours after the exercise, the animals were killed, and the quadriceps were removed. Creatine kinase levels, superoxide production, thiobarbituric acid reactive substances (TBARS) level, carbonyl content, total thiol content, superoxide dismutase, catalase, glutathione peroxidase, interleukin-1b (IL-1?), nuclear factor kappa B (NF-kb), and tumour necrosis factor (TNF) were analysed. Cr supplementation neither decreases Cr kinase, superoxide production, lipoperoxidation, carbonylation, total thiol, IL-1?, NF-kb, or TNF nor alters the enzyme activity of superoxide dismutase, catalase, and glutathione peroxides in relation to the saline group, respectively (P < 0.05). There are positive correlations between Cr kinase and TBARS and TNF-? 48 hours after eccentric exercise. The present study suggests that Cr supplementation does not decrease oxidative stress and inflammation after eccentric contraction. PMID:23560674

Silva, Luciano A; Tromm, Camila B; Da Rosa, Guilherme; Bom, Karoliny; Luciano, Thais F; Tuon, Talita; De Souza, Cláudio T; Pinho, Ricardo A

2013-04-05

245

Structural Assessment of Externally Strengthened Bridge Deck Panels  

NASA Astrophysics Data System (ADS)

Deteriorated concrete bridge decks are strengthened with external bonding technique using either steel plate or various FRPs to enhance the decreased load carrying capacity and serviceability. But the failure characteristics of bridge decks strengthened with various materials can be changed according to mechanical properties of strengthening materials or strengthening scheme as well as the strengthening amount. In this paper, strengthening effect of deck strengthened with carbon fiber sheets, glass fiber sheets or steel plates is compared. And the theoretical load carrying capacity are evaluated using yield line theory and punching shear model properly modified for the strengthened RC member. The panels strengthened with sheet type FRP materials failed more often in a ductile mode, indicating that the failure developed after the rebar yielded.

Sim, Jongsung; Oh, Hongseob; Meyer, Christian

2006-03-01

246

Inhibition of ?-adrenergic tone disturbs the distribution of blood flow in the exercising human limb.  

PubMed

The role of neuronal regulation of human cardiovascular function remains incompletely elucidated, especially during exercise. Here we, by positron emission tomography, monitored tissue-specific blood flow (BF) changes in nine healthy young men during femoral arterial infusions of norepinephrine (NE) and phentolamine. At rest, the ?-adrenoceptor agonist NE reduced BF by ~40%, similarly in muscles (from 3.2 ± 1.9 to 1.4 ± 0.3 ml·min(-1)·100 g(-1) in quadriceps femoris muscle), bone (from 1.1 ± 0.4 to 0.5 ± 0.2 ml·min(-1)·100 g(-1)) and adipose tissue (AT) (from 1.2 ± 0.7 to 0.7 ± 0.3 ml·min(-1)·100 g(-1)). During exercise, NE reduced exercising muscle BF by ~16%. BF in AT was reduced similarly as rest. The ?-adrenoceptor antagonist phentolamine increased BF similarly in the different muscles and other tissues of the limb at rest. During exercise, BF in inactive muscle was increased 3.4-fold by phentolamine compared with exercise without drug, but BF in exercising muscles was not influenced. Bone and AT (P = 0.055) BF were also increased by phentolamine in the exercise condition. NE increased and phentolamine decreased oxygen extraction in the limb during exercise. We conclude that inhibition of ?-adrenergic tone markedly disturbs the distribution of BF and oxygen extraction in the exercising human limb by increasing BF especially around inactive muscle fibers. Moreover, although marked functional sympatholysis also occurs during exercise, the arterial NE infusion that mimics the exaggerated sympathetic nerve activity commonly seen in patients with cardiovascular disease was still capable of directly limiting BF in the exercising leg muscles. PMID:23666670

Heinonen, Ilkka; Wendelin-Saarenhovi, Maria; Kaskinoro, Kimmo; Knuuti, Juhani; Scheinin, Mika; Kalliokoski, Kari K

2013-05-10

247

Strengthening mechanisms of an Al-Mg-Sc-Zr alloy  

Microsoft Academic Search

As a step toward developing an Al-Mg-Sc-Zr alloy for use up to 200 °C, the mechanisms responsible for alloy strengthening were identified for Al-6Mg-2Sc-1Zr (wt%) (Al-6.7Mg-1.2Sc-0.3Zr (at%)). The current work quantifies the active strengthening mechanisms at room temperature and explicitly considers solid solution strengthening, grain boundary strengthening, and Al3(Sc,Zr) precipitate strengthening. Existing strengthening models, together with data from microstructural characterization

K. L. Kendig; D. B. Miracle

2002-01-01

248

Exercise and Asthma  

MedlinePLUS

... Allergies & Asthma > Exercise and Asthma Health Issues Listen Exercise and Asthma Article Body Almost every child (and ... children more likely to develop asthma. How does exercise cause asthma symptoms? The symptoms of asthma are ...

249

Exercise-Induced Bronchoconstriction  

MedlinePLUS

Share | « Back to A to Z Listing Exercise-Induced Bronchoconstriction Exercise-Induced Bronchoconstriction, (EIB), often known as exercise-induced asthma, is a narrowing of the airways causing difficulty moving air out ...

250

Parkinson's Disease: Exercise  

MedlinePLUS

... healthy living for everyone. However, for people with PD exercise is not only healthy, but a vital ... exercise could actually help slow the progression of PD? Learn more about the neuroprotective benefits of exercise ...

251

Exercise and Physical Activity  

MedlinePLUS

... exercise videos/DVDs made for older people. • Add music to the exercises if it helps the person with Alzheimer’s disease. Dance to the music if possible. • Break exercises into simple, easy-to- ...

252

Diabetes and Exercise  

MedlinePLUS

... aerobic exercise include walking, jogging, aerobic dance or bicycling. If you have problems with the nerves in ... stress on your feet. These exercises include swimming, bicycling, rowing or chair exercises. No matter what kind ...

253

Altered cell metabolism in tissues of the knee joint in a rabbit model of Botulinum toxin A-induced quadriceps muscle weakness.  

PubMed

Quadriceps muscle weakness is frequently associated with knee injuries in sports. The influence of quadriceps weakness on knee joint homeostasis remains undefined. We hypothesized that quadriceps weakness will lead to tissue-specific alterations in the cell metabolism of tissues of the knee. Quadriceps weakness was induced with repetitive injections of Botulinum toxin A in six 1-year-old New Zealand White rabbits for 6 months. Five additional animals served as controls with injections of saline/dextrose. Muscle weakness was assessed by muscle wet mass, isometric knee extensor torque, and histological morphology analysis. Cell metabolism was assessed for patellar tendon, medial and lateral collateral ligament, and medial and lateral meniscus by measuring the total RNA levels and specific mRNA levels for collagen I, collagen III, MMP-1, MMP-3, MMP-13, TGF-?, biglycan, IL-1, and bFGF by reverse transcription and polymerase chain reaction. While the total RNA levels did not change, tissue-specific mRNA levels were lower for relevant anabolic and catabolic molecules, indicating potential changes in tissue mechanical set points. Quadriceps weakness may lead to adaptations in knee joint tissue cell metabolism by altering a subset of anabolic and catabolic mRNA levels corresponding to a new functional and metabolic set point for the knee that may contribute to the high injury rate of athletes with muscle weakness. PMID:21496109

Leumann, A; Longino, D; Fortuna, R; Leonard, T; Vaz, M A; Hart, D A; Herzog, W

2011-04-18

254

Strengthening Bridges with Prestressed CFRP Strips  

NASA Astrophysics Data System (ADS)

Limitation of bridge's carrying bearing capacity due to aging and deterioration is a common problem faced by road administration and drivers. Rehabilitation of bridges including strengthening may be applied in order to maintain or upgrade existing bridge parameters. The case studies of strengthening of two small bridges with high modulus prestressed CFRP strips have been presented in the paper. The first one - reinforced concrete slab bridge - and the other - composite steel-concrete girder bridge - have been successfully upgraded with quite new technology. In both cases the additional CFRP reinforcement let increasing of bridge carrying capacity from 15 till 40 metric tons. The CFRP strip prestressing system named Neoxe Prestressing System (NPS), developed by multi-disciplinary team and tested at full scale in Rzeszow University of Technology, has been also described in the paper.

Siwowski, Tomasz; ?ó?towski, Piotr

2012-06-01

255

Process for strengthening silicon based ceramics  

DOEpatents

A process for strengthening silicon based ceramic monolithic materials and omposite materials that contain silicon based ceramic reinforcing phases that requires that the ceramic be exposed to a wet hydrogen atmosphere at about 1400.degree. C. The process results in a dense, tightly adherent silicon containing oxide layer that heals, blunts , or otherwise negates the detrimental effect of strength limiting flaws on the surface of the ceramic body.

Kim, Hyoun-Ee (Oak Ridge, TN); Moorhead, A. J. (Knoxville, TN)

1993-01-01

256

The Strengthening Effect of Percutaneous Vertebroplasty  

Microsoft Academic Search

AIM: To examine whether single-needle vertebroplasty is effective in strengthening vertebrae.MATERIALS AND METHODS: Four adjacent intact lumbar vertebrae were removed from each of nine adult post-mortem subjects. One or two vertebra of each set was injected with low viscosity acrylic bone cement using a single-track posterolateral approach. Vertebral strength was measured during constant rate axial compression.RESULTS: Single-needle injection delivered different

J. R. DEAN; K. T. ISON; P. GISHEN

2000-01-01

257

Process for strengthening silicon based ceramics  

DOEpatents

A process for strengthening silicon based ceramic monolithic materials and composite materials that contain silicon based ceramic reinforcing phases that requires that the ceramic be exposed to a wet hydrogen atmosphere at about 1400{degrees}C. The process results in a dense, tightly adherent silicon containing oxide layer that heals, blunts, or otherwise negates the detrimental effect of strength limiting flaws on the surface of the ceramic body.

Kim, Hyoun-Ee; Moorhead, A.J.

1991-03-07

258

Technical note: double tibial tunnel using quadriceps tendon in anterior cruciate ligament reconstruction.  

PubMed

To avoid complications related to the use of patellar tendon and hamstring (semitendinosus and gracilis) tendon and to create a more anatomic reconstruction, we present a new technique based on the use of quadriceps tendon placed in a single half femoral tunnel and double tibial tunnels. The graft, harvested by a central longitudinal incision, possesses the following characteristics: (1) a bone plug 20 mm long and 10 mm in diameter; (2) a tendon component 7 to 8 cm long, 10 mm wide, and 8 mm thick; and (3) division of the tendon longitudinally into 2 bundles while maintaining the patellar insertion. Every bundle has a width and thickness of approximately 5 mm and 8 mm, respectively. The total length of the graft is 9 to 10 cm. A 10-mm half femoral tunnel is drilled through a low anteromedial portal with the knee flexed at 120 degrees. A suture loop is left in place in the half tunnel. A double tibial tunnel is drilled in a convergent manner (from outside to inside) obtaining an osseous bridge between the 2 tunnels. Two suture loops are passed trough the tibial tunnels and retrieved in a plastic cannula (10 mm) positioned in the anteromedial portal to allow the passage of the 2 bundles in the tibial tunnels. The suture loop left in the half tunnel permits the transportation of the bone plug in the femoral tunnel. Fixation is achieved by an interference screw at the femoral side and by 2 absorbable interference screws (1 for each tunnel). The advantages of this technique are a more cross-sectional area (80 mm(2)), greater bone-tendon interface, and a more anatomic reconstruction. Theoretically, easier bone incorporation, decreased windshield wiper and bungee effect, fewer donor site problems, and less tunnel enlargement can also be possible. PMID:10882460

Pederzini, L; Adriani, E; Botticella, C; Tosi, M

2000-07-01

259

Effect of cyclic preconditioning on the tensile properties of human quadriceps tendons and patellar ligaments.  

PubMed

Preconditioning of soft tissues has become a common procedure in tensile testing to assess the history dependence of these viscoelastic materials. To our knowledge, this is the first study comparing tensile properties of soft tissues-before and after cyclic preconditioning with high loads. Sixteen quadriceps tendon-bone (QT-B) complexes and 16 patellar ligament-bone (PL-B) complexes from a young population (mean age 24.9 +/- 4.4 years) were loaded to failure with a deformation rate of 1 mm/s. Half of the QT-B and the PL-B complexes underwent 200 uniaxial preconditioning cycles from 75 to 800 N at 0.5 Hz before ultimate failure loading. High-load preconditioning was made possible by the development of a highly reliable and easy-to-use cryofixation device to attach the free tendon end. PL-B complexes were more influenced by preconditioning than the QT-B complexes. Ultimate failure load, stiffness at 200 N and stiffness at 800 N were significantly higher for PL-B complexes after preconditioning, while the structural properties of QT-B complexes exhibited no significant alterations. The values of the mechanical properties like Young's modulus at 200 N and 800 N were much higher for both preconditioned specimen groups. In addition, ultimate stress was augmented by preconditioning for PL-B complexes. Hysteresis and creep effects were highest during the first few loading cycles. More than 160 cycles were needed to reach a steady state. Beyond 160 cycles there was no further creep, and hysteresis was almost constant. Creep values were 2.2% of the initial testing length for the QT-B and 3.2% of the initial testing length for the PL-B complexes. The effect of cyclic preconditioning seems to be caused by progressive fiber recruitment and by alterations of the interstitial fluid milieu. PMID:9608465

Schatzmann, L; Brunner, P; Stäubli, H U

1998-01-01

260

Quadriceps neuromuscular function and self-reported functional ability in knee osteoarthritis.  

PubMed

The purposes of this study were to determine 1) the relationships of self-reported function scores in patients with knee osteoarthritis (OA) to both maximal isometric torque and to isotonic power at a variety of loads, and 2) the degree to which muscle volume (MV) or voluntary activation (VA) are associated with torque and power measures in this population. Isometric maximal voluntary contraction (MVC) torque and isotonic power [performed at loads corresponding to 10, 20, 30, 40, and 50% MVC, and a minimal load ("Zero Load")] were measured in 40 participants with knee OA. Functional ability was measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function subscale. MV was determined with magnetic resonance imaging, and VA was measured with the interpolated twitch technique. In general, power measured at lower loads (Zero Load and 10-30% MVC, r(2) = 0.21-0.28, P < 0.05) predicted a greater proportion of the variance in function than MVC torque (r(2) = 0.18, P < 0.05), with power measured at Zero Load showing the strongest association (r(2) = 0. 28, P < 0.05). MV was the strongest predictor of MVC torque and power measures in multiple regression models (r(2) = 0.42-0.72). VA explained only 6% of the variance in MVC torque and was not significantly associated with power at any load (P > 0.05). Quadriceps MVC torque and power are associated with self-reported function in knee OA, but muscle power at lower loads is more predictive of function than MVC torque. The variance in MVC torque and power between participants is due predominantly to differences in MV and has little to do with deficits in VA. PMID:22604883

Berger, M J; McKenzie, C A; Chess, D G; Goela, A; Doherty, T J

2012-05-17

261

Strengthening care of injured children globally  

PubMed Central

Abstract Part of the solution to the growing problem of child injury is to strengthen the care that injured children receive. This paper will point out the potential health gains to be made by doing this and will then review recent advances in the care of injured children in individual institutions and countries. It will discuss how these individual efforts have been aided by increased international attention to trauma care. Although there are no major, well-funded global programmes to improve trauma care, recent guidance documents developed by WHO and a broad network of collaborators have stimulated increased global attention to improving planning and resources for trauma care. This has in turn led to increased attention to strengthening trauma care capabilities in countries, including needs assessments and implementation of WHO recommendations in national policy. Most of these global efforts, however, have not yet specifically addressed children. Given the special needs of the injured child and the high burden of injury-related death and disability among children, clearly greater emphasis on childhood trauma care is needed. Trauma care needs assessments being conducted in a growing number of countries need to focus more on capabilities for care of injured children. Trauma care policy development needs to better encompass childhood trauma care. More broadly, the growing network of individuals and groups collaborating to strengthen trauma care globally needs to engage a broader range of stakeholders who will focus on and champion the improvement of care for injured children.

Abantanga, Francis; Goosen, Jacques; Joshipura, Manjul; Juillard, Catherine

2009-01-01

262

Strengthening of Rural Bridges Using Rapid-Installation FRP Technology.  

National Technical Information Service (NTIS)

Three bridges were strengthened using an innovative method developed at University of Missouri Rolla. It consists of strengthening reinforced concrete members using Fiber Reinforced Polymer (FRP) laminates, having high bearing and longitudinal strengths, ...

A. Nanni A. Rizzo N. Galati

2007-01-01

263

Strengthening Peace Through Civil Society Initiatives at the Community Level.  

National Technical Information Service (NTIS)

This report describes the activities implemented and the financial status of the Program for Strengthening Peace in Colombia during the last quarter of the second year. This period also represents the final report of the Strengthening Peace Through Civil ...

2012-01-01

264

Non-exercising muscle metabolism during exercise  

Microsoft Academic Search

Glycogen decrements have been observed in non-exercising muscles during exercise. We therefore investigated whether the degraded glycogen was retained within the muscle in the form of glycolytic intermediates, or whether it was effluxed from the non-exercising muscles. For these studies a suspension harness was used to unload the hindlimb muscles at rest and during exercise [McDermott et al. (1987) J

John C. McDermott; Geoffrey C. B. Elder; A. Bonen

1991-01-01

265

Influence of infrapatellar and suprapatellar straps on quadriceps muscle activity and onset timing during the body-weight squat.  

PubMed

The use of knee braces for the treatment of patellofemoral pain syndrome (PFPS) is widely documented, yet the mechanism by which such braces alleviate knee pain remains unclear. This study attempted to clarify this issue by simplifying the brace to the level of only straps. The effectiveness of an infrapatellar strap for PFPS remains controversial, and the use of a suprapatellar strap has not yet been studied. Quadriceps muscle activity and onset timing parameters were measured with surface electromyography (EMG) during a body-weight squat in 19 healthy subjects during 4 different knee-strapping conditions (infra, supra, both, and none). No differences in normalized mean or peak EMG activity in any part of the quadriceps were found. The onset timing of the vastus lateralis (VL) was significantly delayed when using an infrapatellar strap (p < 0.05) or both straps (p < 0.05) and marginally delayed when using a suprapatellar strap (p < 0.10) in comparison with the no-strap (control) condition. No differences in the vastus medialis oblique (VMO) onset timing or VMO-VL onset timing difference were found among the strapping conditions, although an improvement in timing was noted with the suprapatellar condition. The results provide novel evidence that the application of an infrapatellar strap, suprapatellar strap, or both straps improves quadriceps muscle timing imbalances by delaying VL onset. Because the largest delay in VL onset occurred when wearing both straps, the combined application of an infrapatellar and suprapatellar strap may be the most beneficial in managing patellofemoral pain. Knee straps, unlike braces, are cost effective, nonrestrictive, and can be universally fitted to any knee and based on the results deserve further study in the patellofemoral pain population. PMID:21912298

Straub, Rachel K; Cipriani, Daniel J

2012-07-01

266

Specific training improves skeletal muscle mitochondrial calcium homeostasis after eccentric exercise.  

PubMed

There is limited understanding of the mitochondrial adaptation following repeated eccentric exercise bouts, a model resulting in muscle adaptation known as the repeat bout effect. It was hypothesized that downhill training would reduce mitochondrial calcium content (MCC) post an acute eccentric bout with concurrent improvements in mitochondrial respiratory function. Thirty-four Sprague-Dawley rats were divided into four groups: control (N), control with acute eccentric exercise (N (ecc)), trained control (X) and trained with acute eccentric exercise (X (ecc)). Training for X and X (ecc) consisted of 30 min per day for five consecutive days of downhill treadmill running. The acute eccentric exercise bout was a -14° treadmill exercise for 90 min performed 2 weeks after the training period. Animals were killed 48 h post-exercise. Isolated mitochondria from the red quadriceps allowed for the measure of mitochondrial respiratory indices and MCC. Calpain activity and heat shock protein 72 expression (HSP72) were also measured. MCC dramatically increased following the acute bout of eccentric exercise in N (ecc) (p < 0.001), but did not change in X (ecc). Mitochondrial respiratory function tended to be slightly depressed in N (ecc) (state 3 respiration, p = 0.053; respiratory control ratio, p = 0.098) and unaltered in X (ecc). Previous training altered the calpain and heat shock protein response to an acute bout of eccentric exercise. The results suggest that downhill exercise training improves mitochondrial calcium homeostasis following an acute bout of prolonged eccentric exercise and may stabilize mitochondrial respiratory function. These improvements coincide with a reduction in calpain activity and heat shock protein upregulation. PMID:22777498

Rattray, Ben; Thompson, Martin; Ruell, Patricia; Caillaud, Corinne

2012-07-10

267

Effect of fluid ingestion on neuromuscular function during prolonged cycling exercise  

PubMed Central

Objectives: To investigate the effects of fluid ingestion on neuromuscular function during prolonged cycling exercise. Methods: Eight well trained subjects exercised for 180 minutes in a moderate environment at a workload requiring ?60% maximal oxygen uptake. Two conditions, fluid (F) and no fluid (NF) ingestion, were investigated. Results: During maximal voluntary isometric contraction (MVC), prolonged cycling exercise reduced (p<0.05) the maximal force generating capacity of quadriceps muscles (after three hours of cycling) and root mean square (RMS) values (after two hours of cycling) with no difference between the two conditions despite greater body weight loss (p<0.05) in NF. The mean power frequency (MPF) for vastus lateralis muscle was reduced (p<0.05) and the rate of force development (RFD) was increased (p<0.05) only during NF. During cycling exercise, integrated electromyographic activity and perceived exertion were increased in both conditions (p<0.05) with no significant effect of fluid ingestion. Conclusions: The results suggest that fluid ingestion did not prevent the previously reported decrease in maximal force with exercise duration, but seems to have a positive effect on some indicators of neuromuscular fatigue such as mean power frequency and rate of force development during maximal voluntary contraction. Further investigations are needed to assess the effect of change in hydration on neural mechanisms linked to the development of muscular fatigue during prolonged exercise.

Vallier, J; Grego, F; Basset, F; Lepers, R; Bernard, T; Brisswalter, J

2005-01-01

268

Rapid hamstrings/quadriceps strength capacity in professional soccer players with different conventional isokinetic muscle strength ratios.  

PubMed

Muscle strength imbalance can be an important factor in hamstrings muscle strain. A hamstrings/quadriceps (H/Q) strength ratio based on concentric peak torque values (Hcon:Qcon) has traditionally been used to describe the potential for knee-joint destabilization. Because certain standard actions in soccer are explosive, the analysis of the H/Q strength ratio based on the rate of torque development (Hrtd:Qrtd) might also be useful in the evaluation of joint stability. The objective of this study was to compare the Hrtd:Qrtd between professional soccer players with heterogeneous values of Hcon:Qcon. Thirty-nine professional soccer players took part in the following procedures on different days: 1) Familiarization session with the isokinetic dynamometer, and 2) Two maximal isometric actions and five maximal concentric actions at 60°·s(-1) for hamstrings (H) and quadriceps (Q). Participants were ranked according to their Hcon:Qcon ratio. The median third was excluded to form a high torque group (HTG), and a low torque group (LTG). Peak isometric (H) and concentric (H and Q) torques and rate of torque development (H) were significantly greater in the HTG group. Similarly, Hcon:Qcon (0.68 ± 0.02 vs. 0.52 ± 0.03) and Hrtd:Qrtd (0.54 ± 0.12 vs. 0.43 ± 0.16) were significantly greater in the HTG group than in the LTG group. There was no significant correlation between Hcon:Qcon and Hrtd:Qrtd. It can be concluded that Hcon:Qcon and Hrtd:Qrtd are determined, but not fully defined, by shared putative physiological mechanisms. Thus, the physiologic and clinical significance of Hcon:Qcon and Hrtd:Qrtd to an athlete's individual evaluation might be different. Key pointsSoccer players with high (0.66-0.70) and low (0.50-0.54) conventional concentric hamstrings:quadriceps ratios (Hcon:Qcon) tend to demonstrate similar profiles (i.e., high and low, respectively) in their rate of the torque development H/Q ratio (Hrtd:Qrtd).The lack of a significant relationship between Hcon:Qcon and Hrtd:Qrtd suggests that these ratios are determined, but not fully defined, by shared putative physiological mechanisms.Preseason screening programs that monitor hamstrings:quadriceps ratios should recognize that the physiologic and clinical significance of Hcon:Qcon and Hrfd:Qrfd to an athlete's individual evaluation might be different. PMID:24149348

Greco, Camila C; Da Silva, Wendell L; Camarda, Sérgio R A; Denadai, Benedito S

2012-09-01

269

Bilateral, simultaneous, spontaneous rupture of the quadriceps tendon. A report of 3 cases and a review of the literature.  

PubMed

Bilateral, simultaneous, spontaneous rupture of the quadriceps tendon is a very rare injury. It usually occurs in the obese older patient (over 50 years). Often, patients are mistakenly treated for rheumatoid arthritis, mild strokes and even neurological paralysis. This diagnostic confusion can lead to a delay in treatment. There is often no history of significant trauma. The pathognomonic signs are a palpable suprapatellar gap and an inability to lift the straight leg. Surgical 'end to end' repair, even of delayed cases, yields satisfactory results. In none of our cases was protective additional tissue reinforcement or a pullout suture used. PMID:3049372

Dhar, S

1988-01-01

270

Effect of exercise-induced fatigue on postural control of the knee.  

PubMed

Muscle fatigue is associated with reduced power output and work capacity of the skeletal muscle. Fatigue-induced impairments in muscle function are believed to be a potential cause of increased injury rates during the latter stages of athletic competition and often occur during unexpected perturbations. However the effect of fatigue on functionally relevant, full body destabilizing perturbations has not been investigated. This study examines the effect of muscle fatigue on the activation of the quadriceps and hamstrings to fast, full body perturbations evoked by a moveable platform. Surface electromyographic (EMG) signals were recorded from the knee extensor (vastus medialis, rectus femoris, and vastus lateralis) and flexor muscles (biceps femoris and semitendinosus) of the right leg in nine healthy men during full body perturbations performed at baseline and immediately following high intensity exercise performed on a bicycle ergometer. In each condition, participants stood on a moveable platform during which 16 randomized postural perturbations (eight repetitions of two perturbation types: 8 cm forward slides, 8 cm backward slides) with varying inter-perturbation time intervals were performed over a period of 2-3 min. Maximal voluntary knee extension force was measured before and after the high intensity exercise protocol to confirm the presence of fatigue. Immediately after exercise, the maximal force decreased by 63% and 66% for knee extensors and flexors, respectively (P<0.0001). During the post-exercise postural perturbations, the EMG average rectified value (ARV) was significantly lower than the baseline condition for both the knee extensors (average across all muscles; baseline: 19.7±25.4?V, post exercise: 16.2±19.4 ?V) and flexors (baseline: 24.3±20.9 ?V, post exercise: 13.8±11.0 ?V) (both P<0.05). Moreover the EMG onset was significantly delayed for both the knee extensors (baseline: 132.7±32.9 ms, post exercise: 170.8±22.9 ms) and flexors (baseline: 139.1±38.8 ms, post exercise: 179.3±50.9 ms) (both P<0.05). A significant correlation (R(2)=0.53; P<0.05) was identified between the percent reduction of knee extension MVC and the percent change in onset time of the knee extensors post exercise. This study shows that muscle fatigue induces a reduction and delay in the activation of both the quadriceps and hamstring muscles in response to rapid destabilizing perturbations potentially reducing the stability around the knee. PMID:22366254

Hassanlouei, H; Arendt-Nielsen, L; Kersting, U G; Falla, D

2012-02-24

271

Implications of group III and IV muscle afferents for high-intensity endurance exercise performance in humans  

PubMed Central

Abstract We investigated the influence of group III/IV muscle afferents on peripheral fatigue, central motor drive (CMD) and endurance capacity during high-intensity leg-cycling. In a double-blind, placebo-controlled design, seven males performed constant-load cycling exercise (318 ± 9 W; 80% of peak power output (Wpeak)) to exhaustion under placebo conditions and with lumbar intrathecal fentanyl impairing spinal ?-opioid receptor-sensitive group III/IV muscle afferents. Peripheral fatigue was assessed via changes in pre- vs. post-exercise quadriceps force in response to supramaximal magnetic femoral nerve stimulation (?Qtw,pot). CMD was estimated via quadriceps electromyogram. To rule out a direct central effect of fentanyl, we documented unchanged resting cardioventilatory responses. Compared to placebo, significant hypoventilation during the fentanyl trial was indicated by the 9% lower /, causing a 5 mmHg increase in end-tidal and a 3% lower haemoglobin saturation. Arterial pressure and heart rate averaged 8 and 10% lower, respectively, during the fentanyl trial and these differences progressively diminished towards end-exercise. Although initially similar, the percent change in CMD was 9 ± 3% higher at end-exercise with fentanyl vs. placebo (P < 0.05). Time to exhaustion was shorter (6.8 ± 0.3 min vs. 8.7 ± 0.3 min) and end-exercise ?Qtw,pot was about one-third greater (–44 ± 2%vs.–34 ± 2%) following fentanyl vs. placebo. The rate of peripheral fatigue development was 67 ± 10% greater during the fentanyl trial (P < 0.01). Our findings suggest that feedback from group III/IV muscle afferents limits CMD but also minimizes locomotor muscle fatigue development by stimulating adequate ventilatory and circulatory responses to exercise. In the face of blocked group III/IV muscle afferents, CMD is less inhibited but O2 transport compromised and locomotor muscle fatigability is exacerbated with a combined net effect of a reduced endurance performance.

Amann, Markus; Blain, Gregory M; Proctor, Lester T; Sebranek, Joshua J; Pegelow, David F; Dempsey, Jerome A

2011-01-01

272

Strengthening public health surveillance and response using the health systems strengthening agenda in developing countries  

PubMed Central

There is increased interest in strengthening health systems for developing countries. However, at present, there is common uncertainty about how to accomplish this task. Specifically, several nations are faced with an immense challenge of revamping an entire system. To accomplish this, it is essential to first identify the components of the system that require modification. The World Health Organization (WHO) has proposed health system building blocks, which are now widely recognized as essential components of health systems strengthening. With increased travel and urbanization, the threat of emerging diseases of pandemic potential is increasing alongside endemic diseases such as human immunodeficiency virus (HIV), tuberculosis (TB), malaria, and hepatitis virus infections. At the same time, the epidemiologic patterns are shifting, giving rise to a concurrent increase in disease burden due to non-communicable diseases. These diseases can be addressed by public health surveillance and response systems that are operated by competent public health workers in core public health positions at national and sub-national levels with a focus on disease prevention. We describe two ways that health ministries in developing countries could leverage President Obama’s Global Health Initiative (GHI) to build public health surveillance and response systems using proven models for public health systems strengthening and to create the public health workforce to operate those systems. We also offer suggestions for how health ministries could strengthen public health systems within the broad health systems strengthening agenda. Existing programs (e.g., the Global Vaccine Alliance [GAVI] and the Global Fund Against Tuberculosis, AIDS, and Malaria [GFTAM]) can also adapt their current health systems strengthening programs to build sustainable public health systems.

2010-01-01

273

Bone mineral density, muscle strength, and recreational exercise in men.  

PubMed

Muscle strength has been shown to predict bone mineral density (BMD) in women. We examined this relationship in 50 healthy men who ranged in age from 28 to 51 years (average 38.3 years). BMD of the lumbar spine, proximal femur, whole body, and tibia were measured by dual-energy x-ray absorptiometry (Hologic QDR 1000W). Dynamic strength using one repetition maximum was assessed for the biceps, quadriceps, and back extensors and for the hip abductors, adductors, and flexors. Isometric grip strength was measured by dynamometry. Daily walking mileage was assessed by 9 week stepmeter records and kinematic analysis of video filming. Subjects were designated as exercisers and nonexercisers. Exercisers participated in recreational exercise at least two times each week. The results demonstrated that BMD at all sites correlated with back and biceps strength (p < 0.01 to p = 0.0001). Body weight correlated with tibia and whole-body BMD (p < 0.001); age negatively correlated with Ward's triangle BMD (p < 0.01). In stepwise multiple regressions, back strength was the only independent predictor of spine and femoral neck density (R2 = 0.27). Further, back strength was the most robust predictor of BMD at the trochanter, Ward's triangle, whole body, and tibia, although biceps strength, age, body weight, and leg strength contributed significantly to BMD at these skeletal sites, accounting for 35-52% of the variance in BMD. Exercisers and nonexercisers were similar for walking (3.97 versus 3.94 miles/day), age (37.8 versus 38.5) years, and weight (80.0 versus 77.7 kg). However, BMD and muscle strength were significantly greater in exercises than in nonexercisers.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1466254

Snow-Harter, C; Whalen, R; Myburgh, K; Arnaud, S; Marcus, R

1992-11-01

274

Exercise Is Medicine.  

ERIC Educational Resources Information Center

Suggests that exercise should be the first-line therapy for preventing and treating many common diseases; however, physicians need more training in how best to use exercise therapy. The paper explains the power of exercise and discusses how to motivate individuals to start safe, enjoyable, and life-saving exercise routines. (SM)

Elrick, Harold

1996-01-01

275

Exercise Is Medicine.  

ERIC Educational Resources Information Center

|Suggests that exercise should be the first-line therapy for preventing and treating many common diseases; however, physicians need more training in how best to use exercise therapy. The paper explains the power of exercise and discusses how to motivate individuals to start safe, enjoyable, and life-saving exercise routines. (SM)|

Elrick, Harold

1996-01-01

276

Strengthening the workforce through meaningful recognition.  

PubMed

Meaningfully recognizing the extraordinary contributions of nurses is a key element in creating and sustaining healthy work environments. Publically honoring the work of nursing reinforces those actions and behaviors that patients, families, and colleagues truly value. A multi-site research study provided a 360-degree perspective of the impact this type of acknowledgment had on strengthening the nursing workforce at 20 health care organizations who use The DAISY Award to recognize extraordinary nurses. Data analysis of 2,195 DAISY Award nominations from patients, families, and colleagues at 20 hospitals identified 22 behavioral themes associated with extraordinary nursing. PMID:23346731

Lefton, Cindy

277

Extended Healing Validation of an Artificial Tendon to Connect the Quadriceps Muscle to the Tibia: 180-day Study  

PubMed Central

Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to nonliving materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contra lateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1400± 93N (vs. 1179± 61 N), linear stiffnesses were 33± 3 N/mm (vs. 37 ± 4N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p = 0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p = 0.3). We believe this technology will yield improved procedures for clinical challenges in orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.

Melvin, Alan J.; Litsky, Alan S.; Mayerson, Joel L.; Stringer, Keith; Juncosa-Melvin, Natalia

2011-01-01

278

Isokinetic strength of the quadriceps and hamstrings and functional ability of anterior cruciate deficient knees in recreational athletes.  

PubMed Central

OBJECTIVE: To test the hypothesis that increasing the hamstrings and quadriceps (H:Q) isokinetic strength ratio will, in the short term, improve the functional ability of an anterior cruciate ligament (ACL) deficient knee. METHODS: The isokinetic muscular characteristics at a speed of 60 degrees s-1 and 180 degrees s-1 of 46 recreational athletes with an arthroscopically confirmed ACL tear were determined using the Cybex II+ isokinetic dynamometer. The variables tested included peak torque, endurance ratio, total work output, and explosive power. Functional ability was scored with the Cincinnati rating system, measuring the severity of pain and swelling, the degree of giving way, and the overall ability to walk, run, ascent and descent stairs, jump and twist. RESULTS: Among all muscular characteristics, the H:Q ratio at 180 degrees s-1 at 30 degrees of knee flexion was shown to have the highest correlation to the functional score (r = 0.6249, P < 0.001). All variables involving hamstring strength were shown to be significantly correlated to the functional ability score (P < 0.01), while none of the variables involving quadriceps strength showed significant correlation with the functional ability of the injured knee. CONCLUSIONS: The H:Q ratio is strongly correlated to the functional ability of ACL deficient knees in Chinese recreational athletes. It could be used as an additional measure to guide in the decision making process in the management of ACL deficient knees.

Li, R C; Maffulli, N; Hsu, Y C; Chan, K M

1996-01-01

279

Strengthening the Canadian alcohol advertising regulatory system.  

PubMed

Research evidence points to harmful effects from alcohol advertising among children and youth. In particular, exposure to alcohol advertising has been associated with adolescents drinking both earlier and heavier. Although current federal and provincial guidelines have addressed advertising practices to prevent underage drinking, practice has not been supported by existing policy. While protective measures such as social marketing campaigns have the potential for counteracting the effects from alcohol advertising, the effectiveness of such measures can be easily drowned out with increasing advertising activities from the alcohol industry, especially without effective regulation. Research reviewed by the European Focus on Alcohol Safe Environment (FASE) Project has identified a set of key elements that are necessary to make alcohol advertising policy measures effective at protecting children and youth from the harmful effects of alcohol marketing. Using these key elements as an evaluation framework, there are critical components in the Canadian alcohol advertising regulatory system that clearly require strengthening. To protect impressionable children and youth against the harmful effects of alcohol advertising, 13 recommendations to strengthen current alcohol advertising regulations in Canada are provided for Canadian policy-makers, advertising standard agencies, and public health groups. PMID:23618638

Heung, Carly M; Rempel, Benjamin; Krank, Marvin

2012-05-24

280

Strengthening the foundations of proliferation assessment tools.  

SciTech Connect

Robust and reliable quantitative proliferation assessment tools have the potential to contribute significantly to a strengthened nonproliferation regime and to the future deployment of nuclear fuel cycle technologies. Efforts to quantify proliferation resistance have thus far met with limited success due to the inherent subjectivity of the problem and interdependencies between attributes that lead to proliferation resistance. We suggest that these limitations flow substantially from weaknesses in the foundations of existing methodologies--the initial data inputs. In most existing methodologies, little consideration has been given to the utilization of varying types of inputs--particularly the mixing of subjective and objective data--or to identifying, understanding, and untangling relationships and dependencies between inputs. To address these concerns, a model set of inputs is suggested that could potentially be employed in multiple approaches. We present an input classification scheme and the initial results of testing for relationships between these inputs. We will discuss how classifying and testing the relationship between these inputs can help strengthen tools to assess the proliferation risk of nuclear fuel cycle processes, systems, and facilities.

Rexroth, Paul E.; Saltiel, David H.; Rochau, Gary Eugene; Cleary, Virginia D.; Ng, Selena (AREVA NC, Paris, France); Greneche, Dominique (AREVA NC, Paris, France); Giannangeli, Don (Texas A& M University, College Station, TX); Charlton, William S. (Texas A& M University, College Station, TX); Ford, David (Texas A& M University, College Station, TX)

2007-09-01

281

Development of Strengthened Bundle High Temperature Superconductors  

SciTech Connect

In the process of developing high temperature superconducting (HTS) transmission cables, it was found that mechanical strength of the superconducting tape is the most crucial property that needs to be improved. It is also desirable to increase the current carrying capacity of the conductor so that fewer layers are needed to make the kilo-amp class cables required for electric utility usage. A process has been developed by encapsulating a stack of Bi-2223/Ag tapes with a silver or non-silver sheath to form a strengthened bundle superconductor. This process was applied to HTS tapes made by the Continuous Tube Forming and Filling (CTFF) technique pursued by Plastronic Inc. and HTS tapes obtained from other manufacturers. Conductors with a bundle of 2 to 6 HTS tapes have been made. The bundled conductor is greatly strengthened by the non-silver sheath. No superconductor degradation as compared to the sum of the original critical currents of the individual tapes was seen on the finished conductors.

Lue, J.W.; Lubell, M.S. [Oak Ridge National Lab., TN (United States); Demko, J.A. [Oak Ridge Inst. for Science and Education, TN (United States); Tomsic, M. [Plastronic, Inc., Troy, OH (United States); Sinha, U. [Southwire Company, Carollton, GA (United States)

1997-12-31

282

Strengthening health research capacity from within Samoa.  

PubMed

This article reflects on the challenges of strengthening health research capacity from within Samoa. It examines the status of health research and related curricula in Samoa and discusses the outcomes of a new postgraduate applied social and health research methods course taught in Samoa for the first time from 5 January to 12 February 2010 by the Department of Preventive and Social Medicine, University of Otago in collaboration with the Centre for Samoan Studies, National University of Samoa. The article argues that collaborative health research courses such as this methods paper can fill a curriculum gap in New Zealand and Samoa and contribute directly toward strengthening Samoa health research capacity in ways that benefit both Samoa and New Zealand. This initiative can be a flagship for strategies operating from within Samoa that can build real win-win type partnerships. These can be ably led by Samoans for the ultimate development of an affordable and sustainable quality health and education infrastructure for Samoa. PMID:21169603

Suaalii-Sauni, Tamasailau; Aiavao, Fulisia; Faafeu-Hope, Eseta; Sopoaga, Tai; Paul, Charlotte; Righarts, Antoinette; McCool, Judith; Kirifi-Alai, Tofilau Nina; Hill, Philip; Fuatai, Fonoti Lafitai I

2011-01-01

283

Strengthening public health surveillance and response using the health systems strengthening agenda in developing countries  

Microsoft Academic Search

There is increased interest in strengthening health systems for developing countries. However, at present, there is common uncertainty about how to accomplish this task. Specifically, several nations are faced with an immense challenge of revamping an entire system. To accomplish this, it is essential to first identify the components of the system that require modification. The World Health Organization (WHO)

Peter Nsubuga; Okey Nwanyanwu; John N Nkengasong; David Mukanga; Murray Trostle

2010-01-01

284

Writing Strengthens Orthography and Alphabetic-Coding Strengthens Phonology in Learning to Read Chinese  

ERIC Educational Resources Information Center

Learning to write words may strengthen orthographic representations and thus support word-specific recognition processes. This hypothesis applies especially to Chinese because its writing system encourages character-specific recognition that depends on accurate representation of orthographic form. We report 2 studies that test this hypothesis in…

Guan, Connie Qun; Liu, Ying; Chan, Derek Ho Leung; Ye, Feifei; Perfetti, Charles A.

2011-01-01

285

Exercisers' identities and exercise dependence: the mediating effect of exercise commitment.  

PubMed

The purpose of this study was to examine the associations of exercise identity, exercise commitment, exercise dependence, and, particularly, the mediating effects of exercise commitment on the relationship between exercise identity and exercise dependence. 253 Taiwanese regular exercisers completed measures, including the Exercise Dependence Scale-Revised, the Exercise Identity Scale, the Exercise Commitment Scale, and the Godin Leisure Time Exercise Questionnaire. Results showed that exercise identity, exercise dependence, and two types of exercise commitment were moderately to highly correlated. Furthermore, structural equation modelling indicated that a "have to" commitment partially mediated the relationship between exercise identity and exercise dependence. Based on the mediating role of a "have to" commitment, the findings are particularly informative to exercise instructors and for exercise program managers. PMID:23265023

Lu, Frank Jing-Horng; Hsu, Eva Ya-Wen; Wang, Junn-Ming; Huang, Mei-Yao; Chang, Jo-Ning; Wang, Chien-Hsin

2012-10-01

286

Physiological benefits of exercise in artificial gravity: A broadband countermeasure to space flight related deconditioning  

NASA Astrophysics Data System (ADS)

Current countermeasures to space flight related physiological deconditioning have not been sufficiently effective. We believe that a comprehensive countermeasure is the combination of intermittent centrifugation (artificial gravity) and exercise. We aim to test the long-term effectiveness of this combination in terms of fitness benefits. As a first-order determination of effectiveness, subjects participated in an eight-week exercise program. Three times per week, they exercised using a stair-stepper on a short-radius (2 m) centrifuge spinning at 30 RPM, maintaining a target heart rate that was systematically increased over the exercise period. During the sessions, foot forces and stepping cadence, heart rate, and perceived exertion were measured. Before and after the eight-week exercise program, measurements included: body fat percentage, bone mineral content, quadriceps extension strength, push-ups endurance, stepping cadence for a given heart rate, and maximum stepping endurance. We find that stair-stepping on a centrifuge is safe and comfortable. Preliminary fitness results indicate that stair-stepping on a centrifuge may be effective in improving aerobic fitness, body composition, and strength. These results indicate that such a combination may also be effective as a countermeasure to space flight deconditioning.

Edmonds, Jessica L.; Jarchow, Thomas; Young, Laurence R.

2008-07-01

287

Imbalance in SOD/CAT activities in rat skeletal muscles submitted to treadmill training exercise.  

PubMed

The association between physical exercise and oxidative damage in the skeletal musculature has been the focus of many studies in literature, but the balance between superoxide dismutase and catalase activities and its relation to oxidative damage is not well established. Thus, the aim of the present study was to investigate the association between regular treadmill physical exercise, oxidative damage and antioxidant defenses in skeletal muscle of rats. Fifteen male Wistar rats (8-12 months) were randomly separated into two groups (trained n=9 and untrained n=6). Trained rats were treadmill-trained for 12 weeks in progressive exercise (velocity, time, and inclination). Training program consisted in a progressive exercise (10 m/min without inclination for 10 min/day). After 1 week the speed, time and inclination were gradually increased until 17 m/min at 10% for 50 min/day. After the training period animals were killed, and gastrocnemius and quadriceps were surgically removed to the determination of biochemical parameters. Lipid peroxidation, protein oxidative damage, catalase, superoxide dismutase and citrate synthase activities, and muscular glycogen content were measured in the isolated muscles. We demonstrated that there is a different modulation of CAT and SOD in skeletal muscle in trained rats when compared to untrained rats (increased SOD/CAT ratio). TBARS levels were significantly decreased and, in contrast, a significant increase in protein carbonylation was observed. These results suggest a non-described adaptation of skeletal muscle against exercise-induced oxidative stress. PMID:17011801

Pinho, Ricardo A; Andrades, Michael E; Oliveira, Marcos R; Pirola, Aline C; Zago, Morgana S; Silveira, Paulo C L; Dal-Pizzol, Felipe; Moreira, José Cláudio F

2006-08-24

288

Changes in transmission in the pathway of heteronymous spinal recurrent inhibition from soleus to quadriceps motor neurons during movement in man  

Microsoft Academic Search

Summary H reflexes were induced in the human quadriceps muscle by electrical stimulation of the femoral nerve. The reflexes were conditioned by prior stimulation of the inferior soleus nerve. The conditioning stimulus produced an inhibition of long duration (>20 ms). The threshold of this inhibition was at zero soleus motor discharge and the inhibition scaled with soleus motor discharge. It

J. F. Iles; Joanne Pardoe

1999-01-01

289

Mechanisms of quadriceps muscle weakness in knee joint osteoarthritis: the effects of prolonged vibration on torque and muscle activation in osteoarthritic and healthy control subjects  

PubMed Central

Introduction A consequence of knee joint osteoarthritis (OA) is an inability to fully activate the quadriceps muscles, a problem termed arthrogenic muscle inhibition (AMI). AMI leads to marked quadriceps weakness that impairs physical function and may hasten disease progression. The purpose of the present study was to determine whether ?-loop dysfunction contributes to AMI in people with knee joint OA. Methods Fifteen subjects with knee joint OA and 15 controls with no history of knee joint pathology participated in this study. Quadriceps and hamstrings peak isometric torque (Nm) and electromyography (EMG) amplitude were collected before and after 20 minutes of 50 Hz vibration applied to the infrapatellar tendon. Between-group differences in pre-vibration torque were analysed using a one-way analysis of covariance, with age, gender and body mass (kg) as the covariates. If the ?-loop is intact, vibration should decrease torque and EMG levels in the target muscle; if dysfunctional, then torque and EMG levels should not change following vibration. One-sample t tests were thus undertaken to analyse whether percentage changes in torque and EMG differed from zero after vibration in each group. In addition, analyses of covariance were utilised to analyse between-group differences in the percentage changes in torque and EMG following vibration. Results Pre-vibration quadriceps torque was significantly lower in the OA group compared with the control group (P = 0.005). Following tendon vibration, quadriceps torque (P < 0.001) and EMG amplitude (P ?0.001) decreased significantly in the control group but did not change in the OA group (all P > 0.299). Hamstrings torque and EMG amplitude were unchanged in both groups (all P > 0.204). The vibration-induced changes in quadriceps torque and EMG were significantly different between the OA and control groups (all P < 0.011). No between-group differences were observed for the change in hamstrings torque or EMG (all P > 0.554). Conclusions ?-loop dysfunction may contribute to AMI in individuals with knee joint OA, partially explaining the marked quadriceps weakness and atrophy that is often observed in this population.

2011-01-01

290

Mood changes following exercise.  

PubMed

26 participants completed a mood measure to assess anger, confusion, depression, fatigue, tension, and vigor immediately before and immediately after two exercise sessions. Analysis showed significant mood enhancement for each exercise session. Follow-up univariate results indicated that Depressed mood scores were reduced significantly and Fatigue scores increased significantly following the first exercise session. Scores after the second exercise session indicated that Depressed mood decreased significantly. There was no interaction. Results lend support for the notion that exercise reduces depressed mood scores. It is suggested that researchers should consider the mechanisms that produce changes in mood following exercise. PMID:12081273

Lane, Andrew M; Crone-Grant, Diane; Lane, Helen

2002-06-01

291

Steps for strengthening the health education profession.  

PubMed

Since its founding in 1950, the Society for Public Health Education (SOPHE) has evolved in response to the changing needs of both the public and the profession. This SOPHE Presidential Address provides a brief review of SOPHE's history and the legacy of its achievements over some 60 years. It also describes how new challenges being created by the pending organizational realignment between SOPHE and the American Association for Health Education, which promises to further unify the profession, along with changing American community demographics, can provide an opportunity for SOPHE to strengthen the health education profession by becoming more inclusive and further redefining Dorothy Nyswander's concept of the "Open Society" and the role health educators play as agents of change. PMID:23027771

Perales, Daniel

2012-10-01

292

Exoplanet HD 209458b (Osiris): Evaporation Strengthened  

NASA Astrophysics Data System (ADS)

Following reanalysis of Hubble Space Telescope observations of primary transits of the extrasolar planet HD 209458b at Ly?, Ben-Jaffel claims that no sign of evaporation is observed. Here we show that, in fact, this new analysis is consistent with the one of Vidal-Madjar and coworkers, and supports the detection of evaporation. The apparent disagreement is mainly due to the disparate wavelength ranges that are used to derive the transit absorption depth. Vidal-Madjar derives a 15% +/- 4% absorption depth during transit over the core of the stellar Ly? line (from -130 to +100 km s-1), and this result agrees with the 8.9% +/- 2.1% absorption depth reported by Ben-Jaffel from a slightly expanded data set but over a larger wavelength range (+/-200 km s-1). These measurements agree also with the 5% +/- 2% absorption reported by Vidal-Madjar over the whole Ly? line from independent, lower resolution data. We show that stellar Ly? variability is unlikely to significantly affect those detections. The H I atoms must necessarily have velocities above the escape velocities and/or be outside the Roche lobe, given the lobe shape and orientation. Absorption by H I in HD 209458b's atmosphere has thus been detected with different data sets, and now with independent analyses. All these results strengthen the concept of evaporating hot Jupiters, as well as the modeling of this phenomenon. Because the escape of H atoms is strengthened in this paper, we renew our proposal to use the nickname ``Osiris'' for the planet HD 209458b, which loses mass like the Egyptian god.

Vidal-Madjar, A.; Lecavelier des Etangs, A.; Désert, J.-M.; Ballester, G. E.; Ferlet, R.; Hébrard, G.; Mayor, M.

2008-03-01

293

Local bone mineral density, muscle strength, and exercise in adolescent boys: a comparative study of two groups with different muscle strength and exercise levels.  

PubMed

The primary objective of the present study was to evaluate the impact of physical activity and muscle strength on bone mineral density (BMD) of the tuberositas tibiae in adolescent boys. Two groups with different exercise levels were compared. The high activity group consisted of 20 subjects (age 15.9 +/- 0.3) from a junior ice hockey team. The reference group consisted of 24 volunteers (age 15.9 +/- 0.3) not training for more than 3 hours per week. The groups were matched for age, weight, and pubertal stage. BMDs (g/cm2) of the tuberositas tibiae and proximal tibia were measured using dual energy X-ray absorptiometry. Quadriceps strength was significantly higher in the high activity group (P < 0.01). Univariate correlations were measured between tuberositas tibiae BMD and pubertal stage, weight, height, BMI, fat mass, lean body mass, quadriceps strength, and hamstrings strength in the high activity group and the reference group, respectively. Quadriceps strength was estimated to be the best significant predictor of BMD of the tuberositas tibiae in the reference group. A multivariate analysis confirmed this result. In the high activity group, there was no significant predictor of BMD of the tuberositas tibiae. There was no significant difference in BMD at this site when comparing the two groups. However, five of the boys in the high activity group had a former history of Mb Osgood-Schlatter with a significantly lower BMD of the tuberositas tibiae than the rest of the boys in that group. After exclusion of these boys, the remaining 15 boys were matched against 20 boys from the reference group using the previous criteria. These 15 boys then showed a significantly higher BMD of the tuberositas tibiae (P < 0.05) but not of the proximal tibia than the 20 boys in the reference group. In conclusion, this study demonstrates site-specific increments of tuberositas tibiae BMD in adolescent ice hockey players unless they are affected by the negative effects on BMD by Mb Osgood-Schlatter. These increments seem primarily to be associated with forceful muscle contractions related to high quadriceps strength and not greater weight-bearing loading. Muscle strength seems to positively affect BMD of the tuberositas tibiae in adolescents, but only up to a certain level, above which additional muscle strength has no effect. PMID:8661480

Nordström, P; Nordström, G; Thorsen, K; Lorentzon, R

1996-06-01

294

Seismic strengthening of RC structures with exterior shear walls  

Microsoft Academic Search

.  Vulnerable buildings and their rehabilitation are important problems for earthquake regions. In recent decades the goal of\\u000a building rehabilitation and strengthening has gained research attention and numerous techniques have been developed to achieve\\u000a this. However, most of these strengthening techniques disturb the occupants, who must vacate the building during renovation.\\u000a In this study, a new strengthening alternative for RC structures,

HASAN KAPLAN; SALIH YILMAZ; NIHAT CETINKAYA; ERGIN ATIMTAY

2011-01-01

295

Continuous Femoral Nerve Blocks: Varying Local Anesthetic Delivery Method (Bolus versus Basal) to Minimize Quadriceps Motor Block while Maintaining Sensory Block  

PubMed Central

Background Whether the method of local anesthetic administration for continuous femoral nerve blocks —basal infusion versus repeated hourly bolus doses —influences block effects remains unknown. Methods Bilateral femoral perineural catheters were inserted in volunteers (n = 11). Ropivacaine 0.1% was administered through both catheters concurrently: a 6-h continuous 5 ml/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. The primary endpoint was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at Hour 6. Secondary end points included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation 2 cm medial to the distal quadriceps tendon in the 22 h following local anesthetic administration initiation. Results Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for limbs receiving 0.1% ropivacaine as repeated bolus doses between baseline and Hour 6 (paired t test P = 0.91). Intrasubject comparisons (left vs. right) reflected a lack of difference as well: the mean basal-bolus difference in quadriceps MVIC at Hour 6 was ?1.1% (95% CI ?22.0 to 19.8%). The similarity did not reach our a priori threshold for concluding equivalence, which was the 95% CI falling within ± 20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration. Conclusions This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration —basal infusion versus repeated bolus doses —influences continuous femoral nerve block effects to a clinically significant degree.

Charous, Matthew T.; Madison, Sarah J.; Suresh, J.; Sandhu, NavParkash S.; Loland, Vanessa J.; Mariano, Edward R.; Donohue, Michael C.; Dutton, Pascual H.; Ferguson, Eliza J.; Ilfeld, Brian M.

2011-01-01

296

Continuous Femoral Nerve Blocks: The Impact of Catheter Tip Location Relative to the Femoral Nerve (Anterior Versus Posterior) on Quadriceps Weakness and Cutaneous Sensory Block  

PubMed Central

Background During a continuous femoral nerve block, the influence of catheter tip position relative to the femoral nerve on infusion characteristics remains unknown. Methods We inserted bilateral femoral perineural catheters in volunteers (ultrasound-guided, needle in-plane). Subjects’ dominant side was randomized to have the catheter tip placed either anterior or posterior to the femoral nerve. The contralateral limb received the alternative position. Ropivacaine 0.1% was administered through both catheters concurrently for 6 hours (4 mL/h). Outcome measures included the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle and tolerance to cutaneous electrical current over to the distal quadriceps tendon. Measurements were performed at Hour 0 (baseline), and on the hour until Hour 9, as well as Hour 22. The primary endpoint was the MVIC of the quadriceps at Hour 6. Results As a percentage of the baseline measurement, quadriceps MVIC for limbs with anterior (n=16) and posterior (n=16) catheter tip placement did not differ to a statistically significant degree at Hour 6 (mean [SD] 29% [26] vs. 30% [28], respectively; 95% CI: ?22% to 20%; p=0.931), or at any other time point. However, the maximum tolerance to cutaneous electrical current was higher in limbs with anterior compared to posterior catheter tip placement at Hour 6 (20 [23] vs. 6 [4] mA, respectively; 95% CI: 1 mA to 27 mA; p=0.035), as well as at Hours 1, 7, 8, and 9 (p<0.04). Conclusions This study documents the significant (70–80%) quadriceps femoris weakness induced by a continuous femoral nerve block infusion at a relatively low dose of ropivacaine (4 mg/h) delivered through a perineural catheter located both anterior and posterior to the femoral nerve. In contrast, an anterior placement increases cutaneous sensory block compared with a posterior insertion, without a concurrent relative increase in motor block.

Ilfeld, Brian M.; Loland, Vanessa J.; Sandhu, NavParkash S.; Suresh, Preetham J.; Bishop, Michael J.; Donohue, Michael C.; Ferguson, Eliza J.; Madison, Sarah J.

2012-01-01

297

EMG evaluation of hip adduction exercises for soccer players: implications for exercise selection in prevention and treatment of groin injuries.  

PubMed

INTRODUCTION: Exercise programmes are used in the prevention and treatment of adductor-related groin injuries in soccer; however, there is a lack of knowledge concerning the intensity of frequently used exercises. OBJECTIVE: Primarily to investigate muscle activity of adductor longus during six traditional and two new hip adduction exercises. Additionally, to analyse muscle activation of gluteals and abdominals. MATERIALS AND METHODS: 40 healthy male elite soccer players, training >5 h a week, participated in the study. Muscle activity using surface electromyography (sEMG) was measured bilaterally for the adductor longus during eight hip adduction strengthening exercises and peak EMG was normalised (nEMG) using an isometric maximal voluntary contraction (MVC) as reference. Furthermore, muscle activation of the gluteus medius, rectus abdominis and the external abdominal obliques was analysed during the exercises. RESULTS: There were large differences in peak nEMG of the adductor longus between the exercises, with values ranging from 14% to 108% nEMG (p<0.0001). There was a significant difference between legs in three of the eight exercises (35-48%, p<0.0001). The peak nEMG results for the gluteals and the abdominals showed relatively low values (5-48% nEMG, p<0.001). CONCLUSIONS: Specific hip adduction exercises can be graded by exercise intensity providing athletes and therapists with the knowledge to select appropriate exercises during different phases of prevention and treatment of groin injuries. The Copenhagen Adduction and the hip adduction with an elastic band are dynamic high-intensity exercises, which can easily be performed at any training facility and could therefore be relevant to include in future prevention and treatment programmes. PMID:23511698

Serner, Andreas; Jakobsen, Markus Due; Andersen, Lars Louis; Hölmich, Per; Sundstrup, Emil; Thorborg, Kristian

2013-03-19

298

Acute alcohol consumption aggravates the decline in muscle performance following strenuous eccentric exercise.  

PubMed

This study investigated the effects of acute moderate alcohol intake on muscular performance during recovery from eccentric exercise-induced muscle damage. Eleven healthy males performed 300 maximal eccentric contractions of the quadriceps muscles of one leg on an isokinetic dynamometer. They then consumed a beverage containing 1g/kg bodyweight ethanol (as vodka and orange juice) (ALC). On another occasion they performed an equivalent bout of eccentric exercise on the contralateral leg after which they consumed an isocaloric quantity of orange juice (OJ). Measurement of maximal isokinetic (concentric and eccentric) and isometric torque produced across the knee, plasma creatine kinase (CK) concentrations and muscle soreness were made before and at 36 and 60h following each exercise bout. All measures of muscle performance were significantly reduced at 36 and 60h post-exercise compared to pre-exercise measures (all p<0.05). The greatest decreases in peak strength were observed at 36h with losses of 12%, 28% and 19% occurring for OJ isometric, concentric, and eccentric contractions, respectively. However, peak strength loss was significantly greater in ALC with the same performance measures decreasing by 34%, 40% and 34%, respectively. Post-exercise plasma creatine kinase activity and ratings of muscle soreness were not different between conditions (both p>0.05). These results indicate that consumption of even moderate amounts of alcohol following eccentric-based exercise magnifies the normally observed losses in dynamic and static strength. Therefore, to minimise exercise related losses in muscle function and expedite recovery, participants in sports involving eccentric muscle work should avoid alcohol-containing beverages in the post-event period. PMID:19230764

Barnes, Matthew J; Mündel, Toby; Stannard, Stephen R

2009-02-20

299

Structural improvement of strengthened deck panels with externally bonded plates  

SciTech Connect

Concrete bridge decks require eventual replacement and rehabilitation due to decreasing load-carrying capacity. This paper compares different strengthening design procedures that improve the usability and structural performance of bridge decks. The failure characteristics of bridge decks strengthened with various materials such as carbon fiber sheet, glass fiber sheet, steel plate, and grid CFRP and GFRP are analyzed, and the theoretical load-carrying capacities are evaluated using traditional beam and yield line theory, and punching shear analysis. The strengthening materials increase the punching shear strength of the deck and change the failure mode of the strengthened panel.

Sim, Jongsung [Department of Civil and Environmental Engineering, Hanyang University, 1271 Sa1-dong, Ansan 425-791 (Korea, Republic of); Oh, Hongseob [Department of Civil and Environmental Engineering, Hanyang University, 1271 Sa1-dong, Ansan 425-791 (Korea, Republic of)]. E-mail: opera69@chollian.net

2005-07-01

300

Hypnotically Assisted Diaphragmatic Exercises in the Treatment of Stuttering: A Preliminary Investigation  

Microsoft Academic Search

This preliminary study investigates the combined effect of intensive hypnotherapy and diaphragmatic exercises in the management of stuttering. Fifty-nine clients with stuttering were trained to practice abdominal weightlifting to strengthen their respiratory muscles and to improve their diaphragmatic movements. The weightlifting exercises involved lifting a dumbbell (2.0–4.0 kg) with the abdomen for 2 hours daily for 8 consecutive days. Hypnotherapy

Yalcin Kaya; Assen Alladin

2012-01-01

301

The effects of left-hand exercises on beginning upper string performers' intonation and facility  

Microsoft Academic Search

The purpose of the study was to examine how beginning upper string instrumentalists' performance facility and intonation accuracy was affected by left-hand exercises. Specifically, do beginning upper string instrumentalists' perform with more accurate intonation and facility when left-hand strengthening and stretching exercises were utilized?Sixty beginning upper string violinists and violists, with less than three years playing experience and from three

Jeannine Mongeon

2004-01-01

302

Boolean Raster Well Exercise  

NSDL National Science Digital Library

Enrique Gomezdelcampo, Bowling Green State University Summary This is a paper and pencil exercise using boolean raster grids. The exercise gives students a better understanding of how the GIS software works. ...

Gomezdelcampo, Enrique

303

Drill and exercise manual.  

National Technical Information Service (NTIS)

The Drill and Exercise Manual establishes the organization, responsibilities, and methodology for developing, conducting, and evaluating drills and exercises at Los Alamos National Laboratory. The procedures established in this manual will ensure that DOE...

G. W. Bequette

1992-01-01

304

Exercise and Physical Fitness  

MedlinePLUS

... Increase your chances of living longer Fitting regular exercise into your daily schedule may seem difficult at ... fine. The key is to find the right exercise for you. It should be fun and should ...

305

Home-Based Exercise  

MedlinePLUS

... Surgical Procedures Types of Vestibular Disorders Home-based Exercise What is a Home VRT program? During vestibular ... is little clinical evidence for its effectiveness. What exercises can I do when I don't have ...

306

Diet and Exercise Tips  

MedlinePLUS

... en Español About Otolaryngology ENT History Diet and Exercise Tips Excessive body weight contributes to snoring and ... Health Statistics concludes that 35 percent of adults exercise regularly (more than 6 of 10 don’t), ...

307

Exercise for Seniors  

MedlinePLUS

Exercise and physical activity are good for just about everyone, including older adults. There are four main ... jogging, dancing, swimming, and biking are examples. Strength exercises make your muscles stronger. Lifting weights or using ...

308

Diet and Exercise  

MedlinePLUS

... Types Risk Factors Prevention & Early Detection Diet And Exercise Transplant recipients need to be aware of the ... help arrange for counseling and other support services. Exercise After a Transplant Most people are weak after ...

309

Diabetes and exercise  

MedlinePLUS

Exercise is an important part of managing your diabetes. It can help you lose weight, if you are overweight. It also helps prevent weight gain. Exercise helps lower your blood sugar without medicines . It ...

310

Anxiety, Depression, and Exercise  

Microsoft Academic Search

Experimental and clinical investigations of the effects of acute and chronic exercise on state anxiety or tension and depression are reviewed. Proposed explanations for the association of exercise with improved mood states are also discussed.

Patricia M. Mihevic

1981-01-01

311

Clinical Applications for Exercise.  

ERIC Educational Resources Information Center

|Patients with chronic conditions such as coronary artery disease, hypertension, diabetes, and obesity might benefit from prescribed exercise. Although exercise does not reverse pathologic changes, it may play a role in disease management. (JD)|

Goldstein, David

1989-01-01

312

Simultaneous chronic rupture of quadriceps tendon and contra-lateral patellar tendon in a patient affected by tertiary hyperparatiroidism  

PubMed Central

Spontaneous ruptures of the extensor mechanism of the knee are very rare. They tend to increase considerably in patients with metabolic diseases such as chronic renal failure, hyperparathyroidism, diabetes, gout, and systemic lupus erythematosus. The reported case regards a 48-year-old man with chronic, spontaneous and simultaneous quadriceps, and contra-lateral patellar tendon rupture. The patient suffered from chronic renal failure and for the past year from tertiary hyperparathyroidism. Ruptured tendons were repaired and both knee were evaluated monthly for the next 12 months. Good functional recovery was achieved on both knees without relapse. This case emphasizes the importance of long-term high parathyroid hormone level in the etiology of tendons ruptures.

Grecomoro, Giuseppe; Martorana, Umberto

2008-01-01

313

Simultaneous chronic rupture of quadriceps tendon and contra-lateral patellar tendon in a patient affected by tertiary hyperparatiroidism.  

PubMed

Spontaneous ruptures of the extensor mechanism of the knee are very rare. They tend to increase considerably in patients with metabolic diseases such as chronic renal failure, hyperparathyroidism, diabetes, gout, and systemic lupus erythematosus. The reported case regards a 48-year-old man with chronic, spontaneous and simultaneous quadriceps, and contra-lateral patellar tendon rupture. The patient suffered from chronic renal failure and for the past year from tertiary hyperparathyroidism. Ruptured tendons were repaired and both knee were evaluated monthly for the next 12 months. Good functional recovery was achieved on both knees without relapse. This case emphasizes the importance of long-term high parathyroid hormone level in the etiology of tendons ruptures. PMID:19384613

Grecomoro, Giuseppe; Camarda, Lawrence; Martorana, Umberto

2008-05-01

314

Writing Strengthens Orthography and Alphabetic-Coding Strengthens Phonology in Learning to Read Chinese  

Microsoft Academic Search

Learning to write words may strengthen orthographic representations and thus support word-specific recognition processes. This hypothesis applies especially to Chinese because its writing system encourages character-specific recognition that depends on accurate representation of orthographic form. We report 2 studies that test this hypothesis in adult learners of Chinese. In those studies, the researchers 1st compared the effects of an online

Connie Qun Guan; Ying Liu; Derek Ho Leung Chan; Feifei Ye; Charles A. Perfetti

2011-01-01

315

Extra articular arthroscopic release in post-traumatic stiff knees: a prospective study of endoscopic quadriceps and patellar release.  

PubMed

Knee stiffness due to mismanaged trauma is still common in underdeveloped countries. Many patients with distal femoral fractures, patellar injuries or other local trauma present with intra-articular and extra-articular adhesions between the quadriceps and anterior femur. Nineteen knees with post trauma stiffness due to combined intra- and extra- articular aetiology were taken up for arthroscopic aided release after failing an aggressive physiotherapy protocol. Ultrasound was used to identify the extra-articular adhesions. The intra-articular part of the release was done by a standard protocol involving the release of all infrapatellar, suprapatellar and gutter adhesions, and then the extra-articular proximal adhesions were released by using special long periosteal elevators and arthroscopic scissors. We were able to release the adhesions as high as 9 inches above the patella, and in one case bony ankylosis between the patella and the femur was arthroscopically osteotomised (after 11 years of stiffness). Delay before surgery averaged 2.7 years (6 months-11.3 years). Mean active flexion at one year follow-up improved from 27.3 degrees to 119.3 degrees (average increase: 92 degrees). Mean preoperative extension lag reduced from 6 degrees to 1 degrees postoperatively. No CPM machine was available, and patients had to undergo daily manual and assisted therapy, with appropriate analgesia. Overall patient satisfaction was excellent; one patient developed a supracondylar fracture (infected old fracture with bone loss and severe contracture) and was retrospectively a wrong case selection. Arthroscopic aided quadriceps adhesion release is a good option in cases of neglected trauma; results are excellent even without sophisticated CPM machines, and the periosteal elevators needed are cheap and indigenous. PMID:16152854

Dhillon, Mandeep S; Panday, Awadesh K; Aggarwal, Sameer; Nagi, Onkar N

2005-04-01

316

Extended healing validation of an artificial tendon to connect the quadriceps muscle to the Tibia: 180-day study.  

PubMed

Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to non-living materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contralateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1,400 ± 93 N (vs. 1,179 ± 61 N), linear stiffnesses were 33 ± 3 N/mm (vs. 37 ± 4 N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p=0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p=0.3). We believe this technology will yield improved procedures for clinical challenges in orthopedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction. PMID:22179930

Melvin, Alan J; Litsky, Alan S; Mayerson, Joel L; Stringer, Keith; Juncosa-Melvin, Natalia

2011-12-16

317

Stretch Band Exercise Program  

ERIC Educational Resources Information Center

This article discusses how to use stretch bands for improving total body fitness and quality of life. A stretch band exercise program offers a versatile and inexpensive option to motivate participants to exercise. The authors suggest practical exercises that can be used in physical education to improve or maintain muscular strength and endurance,…

Skirka, Nicholas; Hume, Donald

2007-01-01

318

Drill and exercise manual  

SciTech Connect

The Drill and Exercise Manual establishes the organization, responsibilities, and methodology for developing, conducting, and evaluating drills and exercises at Los Alamos National Laboratory. The procedures established in this manual will ensure that DOE Order 5500.3A requirements for a coordinated program if drills and exercises as an integral part of emergency management are met.

Bequette, G.W.

1992-07-01

319

Exercise Prescription for Health  

Microsoft Academic Search

Many exercise scientists describe physical activity programs as either exercise for health or exercise for fitness. Data on the dose-response gradient for the relation of physical activity or physical fitness to health and function are reviewed herein to examine this hypothesis. This conceptualization is refuted in this paper. Moderate amounts and moderate intensities of activity or fitness are associated with

Steven N. Blair

1995-01-01

320

Japanese Radio Exercises. Revised.  

ERIC Educational Resources Information Center

|This unit focuses on Japanese radio exercises which became popular in Japan just after World War II and are still used among students and workers in companies to help raise morale and form group unity. The exercises reflect the general role of exercise in Japanese culture--to serve as a symbol of unity and cooperation among the Japanese, as well…

Young, Jocelyn

321

Rotator Cuff Exercises  

MedlinePLUS

... rotator cuff--the part that helps with circular motion). These exercises should not cause you pain. If you feel any pain, stop exercising. Start again with a lighter weight. Look at the pictures with each exercise so you can use the ...

322

Strengthening of Square Reinforced Concrete Plates with Fiber Reinforced Plastics  

Microsoft Academic Search

This paper presents a reasonable numerical model for reinforced concrete structures strengthened by FRP. Proper constitutive models are introduced to simulate the nonlinear behaviors of reinforced concrete and FRP. The finite element program ABAQUS is used to perform the nonlinear failure analysis of the discussed problems. The validity of proposed material models is verified with experimental data and some strengthening

Fu-Ming Lin; Hsuan-Teh Hu

2004-01-01

323

Effect of CFRP plate length strengthening continuous steel beam  

Microsoft Academic Search

This paper focused on behavior of beam strengthened with CFRP plate and effect of strengthening length. The simply supported steel beam tested in previous work was modeled using ANSYS finite element software, The same parameters as the experimental data were used to model the steel beam in FEA. Characteristic points on the load–deflection response curve predicted using finite element analysis

Majid Mohammed Ali Kadhim

324

Torsional Behavior of Reinforced Concrete Beams Strengthened with FRP Composites  

Microsoft Academic Search

Fiber Reinforced Polymer (FRP) as an external reinforcement is used extensively to address the strength requirements related to flexure and shear in structural systems. But the strengthening of members subjected to torsion is yet to be explored. In this paper, the behavior and performance of reinforced concrete members strengthened with externally bonded Glass FRP (GFRP) sheets subjected to pure torsion

Saravanan Panchacharam; Abdeldjelil Belarbi

325

Creep behaviour of CFRP-strengthened reinforced concrete beams  

Microsoft Academic Search

The strengthening of reinforced concrete structures with externally bonded fibre reinforced polymer (FRP) laminates has shown excellent performance and, as a result, this technology is rapidly replacing steel plate bonding techniques. The numerous studies that have been carried out to date on FRP-strengthened concrete elements have mainly focussed on the static and short-term responses; very little work has been done

G. Al Chami; M. Thériault; K. W. Neale

2009-01-01

326

Youth Development and Family Strengthening: A Study of Emerging Connections.  

ERIC Educational Resources Information Center

|This study investigated the ways in which youth organizations support families, highlighting the role of youth organizations in strengthening youth and their families; what youth organizations need to know and do to enhance their prospects for successfully supporting/strengthening youth and their families; and the type of external supports and…

Cahill, Michele; DuPree, Sharon; Pitts, Linda; Thomases, Jean

327

Fire insulation schemes for FRP-strengthened concrete slabs  

Microsoft Academic Search

In recent years, widespread deterioration of civil infrastructure has been a catalyst for the application of externally bonded fiber reinforced polymer (FRP) sheets for reinforcement or strengthening of concrete structures. However, the performance of these FRP strengthening systems in fire is a serious concern, and this represents a critical obstacle to the widespread implementation of FRP repair techniques in buildings.

Brea Williams; Luke Bisby; Venkatesh Kodur; Mark Green; Ershad Chowdhury

2006-01-01

328

Strengthening families to support children affected by HIV and AIDS  

Microsoft Academic Search

This paper provides an overview of the arguments for the central role of families, defined very broadly, and we emphasise the importance of efforts to strengthen families to support children affected by HIV and AIDS. We draw on work conducted in the Joint Learning Initiative on Children and AIDS's Learning Group 1: Strengthening Families, as well as published data and

Linda M. Richter; Lorraine Sherr; Michele Adato; Mark Belsey; Upjeet Chandan; Chris Desmond; Scott Drimie; Mary Haour-Knipe; Victoria Hosegood; Jose Kimou; Sangeetha Madhavan; Vuyiswa Mathambo; Angela Wakhweya

2009-01-01

329

Supporting Teachers, Strengthening Families: A Model Child Abuse Prevention Approach  

ERIC Educational Resources Information Center

This article talks about a model child abuse prevention approach called, "Supporting Teachers, Strengthening Families." It is NAEYC's professional development initiative to help early childhood educators play leading roles in preventing child abuse and neglect through family strengthening efforts. It focuses on six strategies that high-quality…

Olson, Maril

2007-01-01

330

Oxide Dispersion-Strengthened Ferritic Alloys. Dy Data Sheet.  

National Technical Information Service (NTIS)

This publication gives the available data on the DY dispersion-strengthened ferritic alloys developed at C.E.N./S.C.K. Mol, Belgium. DY is a Fe-Cr-Mo ferritic alloy, strengthened by addition of yttrium oxide and of titanium leading to the formation of Chi...

P. van Asbroeck

1976-01-01

331

Exercise for Better Health  

NSDL National Science Digital Library

In this activity you will learn about components of a basic exercise program. You will also find some tips for making exercise a regular part of your life. Finally you will create a simple exercise program that includes the FIT formula. Doggonit!! You really wanted to just sit on the couch, watch another TV program, and eat a bag of chips. Your conscience, on the other hand, is telling you that you really need to get some exercise. What will you do? Hopefully, you are thinking seriously about some exercise. There are ...

2005-12-01

332

Wallace Creek Field Exercises  

NSDL National Science Digital Library

This site contains model class exercises which instructors may find useful as class assignments to accompany class trips to the Wallace Creek site. These exercises are designed for college-level students who have had some background in geology and a general background of fault mechanics and earthquake geology. Particular questions in these exercises requires the students to conduct certain exercises or participate in appropriate discussions regarding geomorphology and slip rates. Five figures necessary to complete certain parts of the exercises are available for downloading.

333

Strengthening of solidified dilute tailings slurry  

SciTech Connect

Tailings produced during mineral processing contain up to 75% or more water and are pumped into settling ponds for disposal. They often become a pollution source due to acid generation. While tailings have been used in underground backfill, the use is very limited at present. This paper presents research results on direct solidification and strengthening of the dilute tailings slurry without dewatering. Two types of tailings were tested at water/binder ratios of up to 4.5 using a special high-water binder. Adequate strength was achieved by solidifying the tailings as is. To further improve the strength, sands and fly ash were used as reinforcement materials or partial replacement of the binder. For oil sands tailings, the 3-day strength was increased by up to 114% with 10--15% additives. For hard rock tailings, up to 30% strength gain was achieved with 15% fly ash addition, and the strength was increased by up to 36% at 10% binder replacement and no strength reduction was observed at 20--25% replacement. These results indicate that higher strength can be achieved with the proper amount of additives and that the backfill process can be simplified and the operation cost reduced.

Zou, D.H.; Li, L.P. [Dalhousie Univ., Halifax, NS (Canada). Dept. Mining and Metallurgical Engineering

1999-01-01

334

Manual Physical Therapy, Cervical Traction, and Strengthening Exercises in Patients With Cervical Radiculopathy: A Case Series  

Microsoft Academic Search

Study Design: A case series of consecutive patients with cervical radiculopathy. Background: A multitude of physical therapy interventions have been proposed to be effective in the management of cervical radiculopathy. However, outcome studies using consistent treatment approaches on a well-defined sample of patients are lacking. The purpose of this case series is to describe the outcomes of a consecutive series

Joshua A. Cleland; Julie M. Whitman; Julie M. Fritz; Jessica A. Palmer

2005-01-01

335

Evidence-informed management of chronic low back pain with lumbar extensor strengthening exercises.  

PubMed

The management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of to The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this supplement were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP. PMID:18164458

Mayer, John; Mooney, Vert; Dagenais, Simon

336

Evidence-informed management of chronic low back pain with lumbar extensor strengthening exercises  

Microsoft Academic Search

Editors' prefaceThe management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions

John Mayer; Vert Mooney; Simon Dagenais

2008-01-01

337

Effect of low-intensity back exercise on quality of life and back extensor strength in patients with osteoporosis: a randomized controlled trial  

Microsoft Academic Search

Summary  Randomized controlled study in 80 postmenopausal women with osteoporosis was conducted to investigate the effect of a home-based,\\u000a simple, low-intensity exercise. Low-intensity back-strengthening exercise was effective in improving the quality of life and\\u000a back extensor strength.\\u000a \\u000a \\u000a \\u000a Introduction and hypothesis  Back-strengthening exercise is effective in increasing back extensor strength and decreasing risk of vertebral fractures.\\u000a We hypothesized that a home-based, simple, low-intensity

M. Hongo; E. Itoi; M. Sinaki; N. Miyakoshi; Y. Shimada; S. Maekawa; K. Okada; Y. Mizutani

2007-01-01

338

Skeletal muscle metabolism during exercise in patients with chronic heart failure.  

PubMed Central

OBJECTIVE: To investigate the metabolic response of skeletal muscle to exercise in patients with chronic heart failure and determine its relation to central haemodynamic variables. SETTING: University hospital in Sweden. PARTICIPANTS: 16 patients in New York Heart Association class II-III and 10 healthy controls. MAIN OUTCOME MEASURES: Skeletal muscle biopsies were obtained from the quadriceps muscle at rest and at submaximal and maximal exercise. Right sided heart catheterisation was performed in eight patients. RESULTS: The patients had lower maximal oxygen consumption than the control group (13.2 (2.9) v 26.8 (4.4) ml/kg/min, P < 0.001). They had reduced activities of citrate synthetase (P < 0.05) and 3-hydroxyacyl-CoA dehydrogenase (P < 0.05) compared with the controls. At maximal exercise adenosine triphosphate (P < 0.05), creatine phosphate (P < 0.01), and glycogen (P < 0.01) were higher whereas glucose (P < 0.001) and lactate (P < 0.06) were lower in the patients than in the controls. Citrate synthetase correlated inversely with skeletal muscle lactate at submaximal exercise (r = -0.90, P < 0.003). No correlations between haemodynamic variables and skeletal muscle glycogen, glycolytic intermediates, and adenosine nucleotides during exercise were found. CONCLUSION: Neither skeletal muscle energy compounds nor lactate accumulation were limiting factors for exercise capacity in patients with chronic heart failure. The decreased activity of oxidative enzymes may have contributed to the earlier onset of anaerobic metabolism, but haemodynamic variables seemed to be of lesser importance for skeletal muscle metabolism during exercise.

Schaufelberger, M.; Eriksson, B. O.; Held, P.; Swedberg, K.

1996-01-01

339

Electromyographic muscle activity in curl-up exercises with different positions of upper and lower extremities.  

PubMed

The purpose of the study was to evaluate the electromyographic (EMG) activity of muscles in curl-up exercises depending on the position of the upper and lower extremities. From the perspective of biomechanics, different positions of the extremities result in shifting the center of gravity and changing muscular loads in abdominal strength exercises. The subjects of the research were 3 healthy students (body mass 53-56 kg and height 163-165 cm) with no history of low back pain or abdominal surgery. Subjects completed 18 trials for each of the 9 exercises (static curl-up with 3 positions of the upper and 3 position of the lower extremities). The same experiment with the same subjects was conducted on the next day. The EMG activity of rectus abdominis (RA), erector spinae (ES), and quadriceps femoris-long head (rectus femoris [RF]) was examined during the exercises. The surface electrical activity was recorded for the right and left sides of each muscle. The raw data for each muscle were rectified and integrated. The statistical analysis showed that changing the position of upper extremities in the examined exercises affects the EMG activity of RA and ES but does not significantly affect the EMG activity of RF. Additionally, it was found that curl-up exercises with the upper extremities extended behind the head and the lower extremities flexed at 90° in the hip and knee joints involve RA with the greatest intensity, whereas curl-up exercises with the upper extremities extended along the trunk and the lower extremities flexed at 90° in the hip and knee joints involve RA with the lowest intensity. PMID:20940638

Rutkowska-Kucharska, Alicja; Szpala, Agnieszka

2010-11-01

340

How the principles of exercise physiology influence pelvic floor muscle training  

Microsoft Academic Search

Clinicians have used pelvic floor muscle training as a behavioral treatment for urinary incontinence for the past 50 years. Various protocols for training these muscles have been tested. Evidence has shown that strengthening the pelvic floor muscle can diminish, and sometimes eliminate, involuntary urine loss. The purpose of this article is to describe the principles of exercise physiology and the

Vicki Y. Johnson

2001-01-01

341

Acute Effect on Power Output of Alternating an Agonist and Antagonist Muscle Exercise During Complex Training  

Microsoft Academic Search

The efficient coordination of agonist and antagonist muscles is one of the important early adaptations in resistance training responsible for large increases in strength. Weak antagonist muscles may limit speed of movement; consequently, strengthening them leads to an increase in agonist muscle movement speed. However, the effect of combining agonist and antagonist muscle exercises into a power training session has

Daniel Baker; Robert U. Newton

2005-01-01

342

Pediatric endurance and limb strengthening for children with cerebral palsy (PEDALS) - a randomized controlled trial protocol for a stationary cycling intervention  

PubMed Central

Background In the past, effortful exercises were considered inappropriate for children with spastic cerebral palsy (CP) due to concern that they would escalate abnormalities including spasticity and abnormal movement patterns. Current scientific evidence indicates that these concerns were unfounded and that therapeutic interventions focused on muscle strengthening can lead to improved functional ability. However, few studies have examined the potential benefits of cardiorespiratory fitness exercises in this patient population. Methods/design The rationale and design of a randomized controlled trial examining the effects of a stationary cycling intervention for children with CP are outlined here. Sixty children with spastic diplegic CP between the ages of 7 and 18 years and Gross Motor Function Classification System (GMFCS) levels of I, II, or III will be recruited for this study. Participants will be randomly assigned to either an intervention (cycling) or a control (no cycling) group. The cycling intervention will be divided into strengthening and cardiorespiratory endurance exercise phases. During the strengthening phase, the resistance to lower extremity cycling will be progressively increased using a uniquely designed limb-loaded mechanism. The cardiorespiratory endurance phase will focus on increasing the intensity and duration of cycling. Children will be encouraged to exercise within a target heart rate (HR) range (70 – 80% maximum HR). Thirty sessions will take place over a 10–12 week period. All children will be evaluated before (baseline) and after (follow-up) the intervention period. Primary outcome measures are: knee joint extensor and flexor moments, or torque; the Gross Motor Function Measure (GMFM); the 600 Yard Walk-Run test and the Thirty-Second Walk test (30 sec WT). Discussion This paper presents the rationale, design and protocol for Pediatric Endurance and Limb Strengthening (PEDALS); a Phase I randomized controlled trial evaluating the efficacy of a stationary cycling intervention for children with spastic diplegic cerebral palsy.

Fowler, Eileen G; Knutson, Loretta M; DeMuth, Sharon K; Sugi, Mia; Siebert, Kara; Simms, Victoria; Azen, Stanley P; Winstein, Carolee J

2007-01-01

343

Exercise-induced bronchoconstriction.  

PubMed

Exercise-induced asthma, or more appropriately, exercise-induced bronchoconstriction (EIB), occurs in 80 to 90% of individuals with asthma and in approximately 11% of the general population without asthma. EIB is characterised by post-exercise airways obstruction resulting in reductions in forced expiratory volume in 1 second (FEV(1)) of greater than 10% compared with pre-exercise values. The mechanism of EIB remains elusive, although both cooling and drying of airways play prominent roles. Cold, dry inhaled air during exercise or voluntary hyperventilation is the most potent stimulus for EIB. Inflammatory mediators play central roles in causing the post-exercise airways obstruction. Diagnosis of EIB requires the use of an exercise test. The exercise can be a field or laboratory based test, but should be of relatively high intensity (80 to 90% of maximal heart rate) and duration (at least 5 to 8 minutes). Pre- and post-exercise pulmonary function should be compared, and post exercise pulmonary function determined over 20 to 30 minutes for characterisation of EIB. A pre- to post-exercise drop in FEV(1) of greater than 10% is abnormal. Approaches to treatment of EIB include both nonpharmacological and pharmacological strategies. A light exercise warm up prior to moderate to heavy exercise reduces the severity of EIB. More recently, studies have supported a role for dietary salt as a modifier of the severity of EIB, suggesting that salt restrictive diets should reduce symptoms of EIB. Short acting, inhaled beta(2)-agonists constitute the most used prophylactic treatment for EIB. However, antileukotriene agents are emerging as effective, well tolerated, long-term treatments for EIB. PMID:12149043

Gotshall, Robert W

2002-01-01

344

Prediction of Obligatory Exercise by Exercise-Related Imagery  

Microsoft Academic Search

Obligatory exercise is a compulsive behavior pattern in which exercise dominates daily life at the expense of other activities and lack of exercise produces withdrawal symptoms. This study examined the hypothesis that obligatory exercise is motivated similarly to eating disorders (cf. S. P. Coen & B. M. Ogles, 1993) and would be predicted by appearance-related imagery. Obligatory exercise (J. K.

Wendy M. Rodgers; Craig R. Hall; Chris M. Blanchard; Krista J. Munroe

2001-01-01

345

Congenital total absence of the quadriceps muscle and patella: a case report with computed tomography scan and three-dimensional reconstructions.  

PubMed

In this study, we present three-dimensional computed tomography (CT) scan image findings of a case with congenital total absence of the quadriceps muscle and patella and partial absence of the sartorius muscle, which caused fixed flexion contracture of the knee joint. Physical examination, radiography, three-dimensional CT scan, and chromosome analysis of the patient were done. On physical examination, the knee joint was at 85 degree fixed flexion contracture. Radiographic views demonstrated soft tissue defects around left femur. Chromosome analysis was normal. CT scan showed total absence of the quadriceps femoris muscle and patella. Congenital absence of the extensor mechanism and patella are very rare anomalies. This case differed from other patellar aplasia or dysplasia syndromes with the presence of fixed flexion knee contracture and aplasia of the extensor mechanism. PMID:22146563

Oner, Mithat; Halici, Mehmet; Guney, Ahmet

2013-07-01

346

Does the peak torque of the hamstring and quadriceps muscles affect the knee laxity measurements in male patients with anterior cruciate ligament rupture?  

Microsoft Academic Search

The aim of the study was to examine whether the peak torque of the hamstring and quadriceps muscles affects the anterior\\u000a knee laxity measurements in male patients. The study comprised 45 male patients who had a chronic unilateral anterior cruciate\\u000a ligament (ACL) rupture. Preoperatively, one experienced physiotherapist performed all the KT-1000 examinations. The anterior\\u000a displacement was registered at 89 Newton.

Ninni Sernert; Jüri Kartus; Kristina Köhler; Lars Ejerhed; Sveinbjörn Brandsson; Jon Karlsson

2000-01-01

347

The time course and magnitude of blood flow changes in the human quadriceps muscles following isometric contraction.  

PubMed Central

Blood velocities in the human femoral artery were measured using pulsed bidirectional Doppler-ultrasound equipment before, during and after single isometric contractions of the quadriceps muscle group. After contraction periods lasting more than 20 s (long) and of tensions from 10% up to 75% of maximal voluntary contraction (m.v.c.), an increase in blood velocities of seven to eight times the resting level was observed. Estimated maximal volume flow to the whole leg during the post-contraction hyperaemic phase calculated from these blood velocity measurements and vessel diameter (measured with echo-ultrasound equipment) was in two of the subjects 2.4 l/min (female) and 4.4 l/min (male), respectively. In the latter, this estimate fitted very well with results obtained using a venous thermo-dilution method. When using computer tomography to estimate the volume of the quadriceps muscle group, the calculated maximum flow to this muscle group in the post-contraction hyperaemic phase was approximately 175 (female) and 185 (male) ml/min. 100 ml muscle, respectively. This was about forty times the estimated resting volume flow to this muscle of 4.7 (female) and 4.5 (male) ml/min. 100 ml muscle. The length of the post-contraction hyperaemia after short (less than 10 s) contraction periods was 12-13 s, by which time velocities had reached 25% above the precontraction level. After long contractions, the corresponding values were 23-25 s. By contrast, previous plethysmographic observations by others indicate that postcontraction hyperaemias following long contractions last 10-15 min. There was a marked difference between the times taken to reach maximal velocity in the hyperaemic phase when comparing short and long contractions. Maximal velocity was reached four to six cardiac cycles following short periods of contraction but during the very first heart beat after long periods of contractions. The present observations are compatible with the hypothesis that locally released metabolites or hormones play a dominant role in the regulation of the post-contraction hyperaemia. Since during the short contraction periods maximal velocity was reached only after some seconds, whereas with the longer contraction periods it was reached during the first heart beat, it is suggested that these metabolites are released at some distance from the resistance vessels and that some time is needed for diffusion.

Wesche, J

1986-01-01

348

Motor unit recruitment when neuromuscular electrical stimulation is applied over a nerve trunk compared with a muscle belly: quadriceps femoris.  

PubMed

Neuromuscular electrical stimulation (NMES) can be delivered over a nerve trunk or muscle belly and both can generate contractions through peripheral and central pathways. Generating contractions through peripheral pathways is associated with a nonphysiological motor unit recruitment order, which may limit the efficacy of NMES rehabilitation. Presently, we compared recruitment through peripheral and central pathways for contractions of the knee extensors evoked by NMES applied over the femoral nerve vs. the quadriceps muscle. NMES was delivered to evoke 10 and 20% of maximum voluntary isometric contraction torque 2-3 s into the NMES (time(1)) in two patterns: 1) constant frequency (15 Hz for 8 s); and 2) step frequency (15-100-15 Hz and 25-100-25 Hz for 3-2-3 s, respectively). Torque and electromyographic activity recorded from vastus lateralis and medialis were quantified at the beginning (time(1)) and end (time(2); 6-7 s into the NMES) of each pattern. M-waves (peripheral pathway), H-reflexes, and asynchronous activity (central pathways) during NMES were quantified. Torque did not differ regardless of NMES location, pattern, or time. For both muscles, M-waves were ?7-10 times smaller and H-reflexes ?8-9 times larger during NMES over the nerve compared with over the muscle. However, unlike muscles studied previously, neither torque nor activity through central pathways were augmented following 100 Hz NMES, nor was any asynchronous activity evoked during NMES at either location. The coefficient of variation was also quantified at time(2) to determine the consistency of each dependent measure between three consecutive contractions. Torque, M-waves, and H-reflexes were most variable during NMES over the nerve. In summary, NMES over the nerve produced contractions with the greatest recruitment through central pathways; however, considering some of the limitations of NMES over the femoral nerve, it may be considered a good complement to, as opposed to a replacement for, NMES over the quadriceps muscle for maintaining muscle quality and reducing contraction fatigue during NMES rehabilitation. PMID:22556395

Bergquist, A J; Wiest, M J; Collins, D F

2012-05-03

349

OXIDE DISPERSION-STRENGTHENED HEAT EXCHANGER TUBING  

SciTech Connect

Oxide dispersion strengthened (ODS) alloys (e.g. the INCOLOY{reg_sign} MA956 alloy) are known for their excellent high temperature properties and are prime candidate materials for the construction of very high temperature heat exchangers that will be used in Vision 21 power plants. The main limitation of these materials is their poor weldability. Commercially available ODS tubing also tends to exhibit relatively poor circumferential creep strength due to current processing practices resulting in a fine grain size in the transverse direction. Thus far, these two characteristics of the ODS tubing have restricted its use to mostly non-pressure containing applications. The objectives of this program are to develop: (a) an MA956 tube with sufficient circumferential creep strength for long term use as heat exchanger tubing for very high temperatures; (b) a welding technique(s) for producing adequate joints between an MA956 tube and an MA956 tube, and an MA956 tube and an INCONEL 601 tube; (c) the bending strain limits, below which recrystallization will not occur in a MA956 tube during normal operation; and (d) the high temperature corrosion limits for the MA956 alloy with respect to working-fluid side and fireside environments. Also, this program seeks to generate data for use by heat exchanger designers and the ASME Boiler and Pressure Vessel Code, and perform an analysis of the mechanical property, tube bending, and corrosion data in order to determine the implications on the design of a very high temperature heat exchanger (T>1093 C/2000 F). After one year, work is currently being conducted on increasing the circumferential strength of a MA956 tube, developing joining techniques for this material, determining the tube bending strain limits, and establishing the high temperature corrosion parameters for the MA956 alloy in environments expected to be present in Vision 21 power plants. Work in these areas will is continuing into the next fiscal year, with success anticipated to produce innovative developments that will allow the reliable use of ODS alloys for heat exchanger tubing, as well as a variety of applications previously not possible with metallic materials.

Harper, Mark A.

2001-11-06

350

Fault Zone Strengthening and Tectonic Reactivation (Invited)  

NASA Astrophysics Data System (ADS)

Tectonic reactivation of geologic faults occurs commonly and for a wide range of spatiotemporal scales and rock types. Fault reactivation may involve weakening processes during periods of tectonic inactivity and/or it may represent the slow pace of fault zone restrengthening, such that faults remain weaker than their surroundings for long time scales. The geometric and structural complexity of tectonic fault zones suggests that fault zone maturity and mineralogy, among other variables, may play a role in determining the conditions under which reactivation occurs. Laboratory experiments focused on frictional processes can offer insight on fault reactivation in the brittle crust via evaluation of frictional healing and weakening. Indeed, many such studies have been conducted to evaluate fault healing in the context of the seismic cycle, which requires that faults restrengthen (heal) between earthquakes. Frictional healing, as evidenced by increasing static friction during quasi-stationary contact, is considered the most likely mechanism of interseismic and dynamic fault strengthening, and there is good agreement between laboratory-based friction laws and field observations of fault healing in some cases. Laboratory observations show that the frictional yield stress increases linearly with log time and that the rate of frictional healing varies with shear stress, chemical environment, mineralogy, and temperature. For quartzofeldspathic rocks the healing rate (expressed as a change in friction coefficient per decade change in waiting time, measured in seconds) ranges from 0.01-0.1, depending on temperature. If these rates extend to geologic time scales, they imply that faults will still be weaker, in a Coulomb-Mohr sense, than their surroundings even after >>108 years. That is, if the coefficient of fault friction goes up by 0.05 per decade in time, and if we start at 0.6, then the effective friction coefficient would be ~1.35 after 108 years. This value is below the strength of intact rock assuming typical values of cohesion and internal friction. This is clearly a very simplified view, but if provides a starting point for discussing fault healing and reactivation. In this talk, I draw on results from studies of frictional healing and stick-slip to address the issue of tectonic fault reactivation.

Marone, C.

2009-12-01

351

Dietary antioxidants and exercise  

Microsoft Academic Search

Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary

SCOTT K. POWERS; KEITH C. DERUISSEAU; John Quindry; KARYN L. HAMILTON

2004-01-01

352

Exercise and Memory  

NSDL National Science Digital Library

This activity (on page 2 of the PDF) is a full inquiry investigation into the effects of exercise on short term memory. Groups of learners will set a baseline score with an initial memory test. Then they split into two teams, one participating in physical exercise while the other remains sedentary. After ten minutes, both teams take another memory test to tabulate and graph score changes. Relates to linked video, DragonflyTV: Exercise and Memory.

Twin Cities Public Television, Inc.

2005-01-01

353

Understanding Exercise Dependence  

Microsoft Academic Search

Exercise dependence represents a condition in which an individual exercises excessively, often to the detriment of his or\\u000a her physical and psychological health and wellbeing. Despite substantial investigation of this phenomenon, researchers have\\u000a only recently developed conceptually sound diagnostic criteria for exercise dependence, and have yet to determine a suitably\\u000a convincing mechanism or explanation for its onset and development. Likewise,

Jeremy Adams

2009-01-01

354

Exercise and freedom  

Microsoft Academic Search

Why do most people fail to exercise regularly? In light of theory and research, this paper shows that fitness activity is an affront to people’s sense of freedom; thus, it becomes a freedom-killing and leisure-killing activity. People fail to exercise because they cannot overcome the issue of freedom about exercise. Further, unlike other leisure activities, fitness activity also fails to

Seppo E. Iso-Ahola

2009-01-01

355

Exercise and children's health.  

PubMed

Every child and adolescent needs exercise, which is a risk-free investment for current and future health. Physicians can help parents and children understand the importance of exercise and help them select safe, enjoyable, age-appropriate activities. This article discusses current literature regarding exercise and its effects on children's health, including nutrition and cardiovascular issues. It also reviews the epidemiology and treatment of injuries in young athletes, including preventative measures. PMID:12831683

Lou, Julia E; Ganley, Theodore J; Flynn, John M

2002-12-01

356

Exercise for the Overweight Patient.  

ERIC Educational Resources Information Center

Exercise can help patients maintain lean body mass during weight loss. Although exercise is not extremely useful in shedding excess pounds, it helps keep off weight lost through calorie restriction. This article discusses the specifics of exercise prescription, types of exercise, motivation to exercise, and special problems such as diabetes. (SM)

Work, Janis A.

1990-01-01

357

Exercise for the Overweight Patient.  

ERIC Educational Resources Information Center

|Exercise can help patients maintain lean body mass during weight loss. Although exercise is not extremely useful in shedding excess pounds, it helps keep off weight lost through calorie restriction. This article discusses the specifics of exercise prescription, types of exercise, motivation to exercise, and special problems such as diabetes. (SM)|

Work, Janis A.

1990-01-01

358

Addition of synchronous whole-body vibration to body mass resistive exercise causes little or no effects on muscle damage and/or inflammation.  

PubMed

The purpose of this study was to determine if a moderate intensity whole-body vibration (WBV) body mass resistive exercise session causes additional muscle damage, soreness and inflammation compared to the same exercise session without vibration (NoV). Ten recreationally active male university students completed two separate 24 h study periods incorporating an exercise session with WBV or NoV. Muscle torque was measured (at 0, 60, and 240°·s angular velocities), soreness (10 point scale) in the upper [UE (triceps)] and lower [LE (quadriceps)] extremities, and muscle inflammation markers (interleukin 1?, 6, 10) were measured at 4 time points (pre-exercise, immediately post-exercise, 4 h post, and 24 h post). Diet was controlled. Compared to NoV, WBV increased (P<0.01) muscle soreness at 24 h post-exercise in both the UE (2.2±1.7 vs 0.6±0.9) and LE (2.0±1.5 vs 0.7±0.7). Muscle torque was decreased immediately post-exercise (P<0.05) in the UE and LE at 0°·s and in the UE at 240°·s, but there was no difference between exercise treatments. The exercise session caused significant but small increases in IL-1? and IL-6 but with no differences between exercise treatments. IL-10 was increased with WBV (2.9±2.0 to 3.6±1.9 pg·ml; P<0.03). These data suggest the addition of WBV to exercise has little effect on muscle function/damage, soreness, or inflammation. PMID:23615482

Hazell, Tom J; Olver, T Dylan; Hamilton, Craig D; Lemon, Peter W R

2013-04-23

359

Exercise and Fibromyalgia  

MedlinePLUS

... Articles Español Acupuncture Advocacy Alternative Therapies Animals Chiropractic Depression Diagnosis Disability Doctor-Patient Relationship Exercise Fibrofog Finances Goal Setting Hands-on Therapies Holidays ...

360

Exercise in hypertrophic cardiomyopathy.  

PubMed

The risk of sudden cardiac death (SCD) associated with vigorous athletic competition in individuals with hypertrophic cardiomyopathy (HCM) is well documented, and is the basis for recommended exclusion from competitive sports independent of other risk factors. Although SCD risk with recreational exercise is less well defined, published guidelines for participation in recreational sports, based on a consensus of expert opinion, offer a valuable framework for counseling patients. Exercise stress testing is an important diagnostic and prognostic tool in the evaluation of HCM patients, providing an objective measure of functional capacity, physiologic hemodynamic responses to stress, presence of ischemia, and provocable left ventricular outflow tract obstruction. The value of cardiopulmonary exercise testing in HCM is less well studied than in the heart failure population, but can be used to set a safe target for exercise intensity as part of an individualized exercise prescription. The long-term effects of exercise on HCM pathophysiology are largely theoretical at this stage. Potential harmful effects of fatiguing exercise include prolonged contractile dysfunction resulting from microvascular ischemia and energetic compromise. Conversely, several animal studies have shown that voluntary exercise prevents or reverses many pathologic features of HCM, including those related to apoptosis and energetics. Substantial evidence for health-promoting benefits of exercise in the general population, in addition to promising safety and efficacy data in patients with chronic heart failure, emphasizes the need to attain a reasonable balance between potential risks and benefits of aerobic fitness in individuals with HCM. PMID:20559999

Day, Sharlene M

2009-10-14

361

Shear Strengthening of Pretensioned Prestressed Concrete Composite Flexural Members.  

National Technical Information Service (NTIS)

Strengthening is required due to inadequacy which typically results from a poor design, a change in usage, or a change in design loads. Prestressed composite beams require special attention in connection with their behavior in horizontal shear at the comp...

R. Aboutaha N. Burns

1991-01-01

362

Strategy to Protect and Strengthen Development in Southern Africa.  

National Technical Information Service (NTIS)

This paper offers an overarching strategy for the United States (U.S.) and USAFRICOM in protecting and strengthening social economic development in central and southern Africa. First, this paper provides a background of the recent and current political co...

R. K. Carlson

2009-01-01

363

Postal Service Needs to Strengthen Controls Over Employee Overtime.  

National Technical Information Service (NTIS)

To strengthen controls over overtime expenditures, the Postal Service needs to: (1) Include planned overtime in its budget and work-hour reports; (2) Periodically determine whether overtime work can be done on straight time; (3) Determine the reasons for ...

1983-01-01

364

Doctor's Eye Contact Strengthens Bond with Patient, Study Finds  

MedlinePLUS

... on this page, please enable JavaScript. Doctor's Eye Contact Strengthens Bond With Patient, Study Finds Study used ... that suggests patients like doctors who make eye contact and think they're more empathetic. "The goal ...

365

Strengthening Board - Staff Collaboration in Community Mental Health Programs.  

National Technical Information Service (NTIS)

A continuing education program for selected mental health professionals and board members is designed to strengthen, board - staff collaboration in development and interpretation of community health programs. The program is sponsored by the School of Soci...

D. W. Rieman

1976-01-01

366

Strengthening Methodology for Lightly Reinforced Concrete Frames-I.  

National Technical Information Service (NTIS)

An analytical method for evaluating the inelastic dynamic structural response of lightly reinforced concrete (RC) frames strengthened by infilled shear walls was developed. The method consists of the development of hysteresis failure models for existing a...

D. R. Todd H. S. Lew L. T. Phan

1993-01-01

367

Parents Anonymous (SM): Strengthening Families. Juvenile Justice Bulletin.  

National Technical Information Service (NTIS)

Problems arising within the family may lead to problem behaviors with adverse consequences for children and communities. Strengthening families is a fundamental principle of OJJDP's Comprehensive Strategy for Serious, Violent, and Chronic Juvenile Offende...

L. Pion-Berlin T. Rafael

1999-01-01

368

Tests of reinforced concrete beams strengthened with wire rope units  

Microsoft Academic Search

This paper presents a simple unbonded-type shear strengthening procedure for reinforced concrete structures with wire rope units. Fifteen beams were tested to failure in shear, repaired, strengthened using the proposed wire rope units, and then retested. The main variables investigated were the shear span-to-depth ratio, and the prestressing force, orientation and spacing of wire rope units. The shear strength of

S. Y. Kim; K. H. Yang; H. Y. Byun; A. F. Ashour

2007-01-01

369

Leptin and exercise.  

PubMed

Short-term exercise (<60 min) studies suggest that leptin concentrations are not acutely affected in healthy males and females. Most reports of reductions in serum leptin may be attributed to circadian rhythms or hemoconcentration. For long-term (> or =60 min) exercise, a reduction in leptin concentrations reported from 1 to 3 hr of running or cycling has been attributed to diurnal reduction in circulating leptin, independent of exercise. Exercise that produces a sufficient energy imbalance (kilocalorie intake versus kilocalorie expenditure) suppresses 24-hr mean and amplitude of the diurnal rhythm of leptin in women. Suppression of leptin concentrations may be counterbalanced by feeding and may explain consistent reports of reductions in leptin concentrations following extreme bouts of exercise such as marathons or ultramarathons. In addition, leptin concentrations are reduced 48 hr after long-term aerobic exercise and long-term resistance exercise is associated with delayed leptin reduction 9 hr postexercise. Training studies have documented that short-term exercise training (< or =12 weeks) does not affect leptin levels, with the exception of patients with type 2 diabetes. Exercise training protocols that result in reduced fat mass will lower leptin concentrations, thus, most investigators have reported leptin concentrations after accounting for fat loss. There are disparate findings concerning long-term (>12 weeks) training studies, with a number of studies finding no effect of training on leptin concentrations other than effects induced by fat loss, and other studies finding reductions in leptin concentrations after accounting for fat loss. Exercise training-induced reductions in leptin levels have been attributed to alterations in energy balance, improvements in insulin sensitivity, alterations in lipid metabolism, and unknown factors. Hormone replacement does not seem to affect leptin adaptations to training. Patients with type 2 diabetes show delayed effects of short-term resistance exercise on leptin concentrations, reduced leptin levels with long-term training, and appear to be more sensitive to training-induced leptin adaptations than other populations. PMID:12324651

Kraemer, Robert R; Chu, Hongnan; Castracane, V Daniel

2002-10-01

370

Exercise and diabetes.  

PubMed

Diet and exercise form the foundation of a healthy lifestyle. These are especially important for people living with diabetes mellitus, as they are the most practical non-pharmacological means by which patients may significantly improve their blood glucose levels. Exercise increases insulin sensitivity (both short and long term), lowers blood sugar levels, reduces body fat and improves cardiovascular (CV) function. Because of this, exercise offers enormous benefit to patients with diabetes. Blood glucose levels can significantly drop during and after physical activities, due to the increased utilisation of glucose as a fuel during exercise and the up-regulation of glucose transport into working muscles. Therefore, patients (especially those with type 1 diabetes) must account for the effects of exercise and adjust their medications and nutrition accordingly. Improvements in real-time continuous glucose monitoring and optimisation of basal insulin dosing may offer significant benefit to preventing hypoglycaemia in patients with type 1 diabetes who regularly exercise. Diverse exercise programmes and devices can also assist patients in monitoring their activities as well as motivating them to achieve their exercise goals. For patients with type 1 diabetes, questions such as how much, how long, how strenuous and what kind of exercise must be addressed in order for healthcare professionals to offer maximum benefit to their patients. Additionally, since patients with type 2 diabetes often have other significant co-morbidities such as obesity and CV disease, care providers must evaluate each patient's risk factors before designing an exercise programme. Several publications in the last year have addressed these issues and may serve as a valuable resource to provide safe and effective recommendations to patients and their healthcare providers. To be included in the Exercise and Diabetes chapter for the 2010 YEARBOOK, we reviewed leading peer-reviewed manuscripts that were published in the period July 2009 to June 2010. PubMed was used in the initial screening of articles. PMID:21323815

Zisser, H; Gong, P; Kelley, C M; Seidman, J S; Riddell, M C

2011-02-01

371

Relationship between quadriceps femoris muscle volume and muscle torque at least 18 months after anterior cruciate ligament reconstruction.  

PubMed

The purpose of this study was to evaluate motor unit recruitment in the quadriceps femoris (QF) after anterior cruciate ligament (ACL) rupture and repair. Subjects included 24 patients at ? 18 months after ACL reconstruction and 22 control subjects with no history of knee injury. A series of cross-sectional magnetic resonance images were obtained to compare the QF of patients' injured side with that of their uninjured sides and that of uninjured control subjects. Muscle torque per muscle volume was calculated as isokinetic peak torque divided by QF muscle volume (cm(3)). The mean muscle torque per unit volume of the injured side of patients was not significantly different from that of the uninjured side or control subjects (one-way ANOVA) Results of the present study were contrary to the results of a previous study that evaluated patients at ? 12 months after ACL reconstruction. The present study found that high-threshold motor unit recruitment was restored at ? 18 months after ACL reconstruction. Thus, clinicians must develop techniques that increase the recruitment of high-threshold motor units in the QF from the period immediately after the injury until approximately 18 months after ACL reconstruction. PMID:21599756

Konishi, Y; Oda, T; Tsukazaki, S; Kinugasa, R; Fukubayashi, T

2011-05-23

372

Acute effects of static and dynamic stretching on hamstring eccentric isokinetic strength and unilateral hamstring to quadriceps strength ratios.  

PubMed

The main purposes of this study were to investigate the acute effects of static and dynamic lower limb stretching routines: (a) on peak torque, total external work and joint angle at peak torque of the hamstrings during maximal eccentric isokinetic leg flexion; (b) on unilateral hamstring to quadriceps (H/Q) strength ratios; as well as (c) to determine whether static and dynamic routines elicit similar responses. A total of 49 active adults completed the following intervention protocols in a randomised order on separate days: (a) non-stretching (control condition), (b) static stretching, and (c) dynamic stretching. After the stretching or control intervention, eccentric isokinetic peak torque, the angle of peak torque and total external work were assessed with participants prone at 1.04 and 3.14 rad · s(-1). Unilateral strength ratios of the knee were also recorded. Measures were compared via a fully-within-groups factorial analysis of variance (ANOVA). There were no main effects for eccentric isokinetic peak torque, angle of peak torque, total external work and unilateral H/Q strength ratios. The results suggest that dynamic and static stretching has no influence on eccentric strength profile and unilateral H/Q strength ratios and hence both forms of stretching do not reduce these two primary risk factors for muscle injury. PMID:23230900

Ayala, Francisco; De Ste Croix, Mark; Sainz De Baranda, Pilar; Santonja, Fernando

2012-12-12

373

Quadriceps keystone island flap for radical inguinal lymphadenectomy: a reliable locoregional island flap for large groin defects.  

PubMed

Background:? Radical inguinal lymphadenectomy (RIL) for bulky metastatic melanoma and non-melanoma skin cancers of the inguinal region, while shown to improve morbidity and survival oncologically, can result in substantial morbidity from wound complications. Skin defects cannot be closed primarily and the substantial dead space predisposes to seroma, wound dehiscence and infection. Despite the clear need for reconstructive options, extended series describing reconstruction of large inguinal defects in this setting have not been reported. Methods:? A prospectively entered, retrospectively reviewed study of 20 consecutive patients undergoing quadriceps keystone island flaps (QKIF) for the closure of complicated inguinal defects is described. Results:? There was 100% flap survival, with no partial or complete flap losses. A reduction in wound breakdown/dehiscence from reported rates was seen, with four patients (20%) having wound breakdown, compared to double that rate in reported series. Other wound complications comprised six patients (30%) with mild wound infections, seven patients (35%) with seromas and two patients (10%) with haematomas. Conclusion:? The QKIF is an effective means of reconstructing inguinal defects after RIL, particularly in high-risk patients, and is technically simpler than other reconstructive techniques advocated for this purpose. Furthermore, the QKIF offers patients with advanced disease (where management is primarily palliative) a potentially improved quality of life with reduced operative morbidity. PMID:22507632

Behan, Felix C; Paddle, Alenka; Rozen, Warren M; Ye, Xuan; Speakman, David; Findlay, Michael W; Henderson, Michael A

2011-05-17

374

Change in knee kinematics during gait after eccentric isokinetic training for quadriceps in subjects submitted to anterior cruciate ligament reconstruction.  

PubMed

Knee kinematics after anterior cruciate ligament (ACL) reconstruction is of interest in studies evaluating the effect of training programs. Many studies have addressed knee flexion/extension but not valgus/varus movements. Considering that joint stability is a major concern in ACL reconstruction surgery, movements occurring in the frontal plane of the knee also deserve attention. Knee extensor torque was analyzed by an isokinetic dynamometer and the angular amplitudes and velocities of flexion/extension and valgus/varus movements were analyzed by goniometry during gait 9 months after ACL reconstruction. The analysis was repeated after 3 months of eccentric isokinetic training of the quadriceps in five patients. The gait pattern was also recorded for 10 healthy controls. The knee extensor torque and flexion/extension range of movement during gait increased significantly after training. However, an unexpectedly increased valgus, most pronounced during the swing phase, which may imply adverse effects on the knee, was also observed in the ACL reconstructed knee. The recorded valgus angles may however be overestimated due to crosstalk. Thus, the extent of the increased valgus, as well as the mechanisms involved and the functional and clinical implications, need clarification before eccentric training after ACL reconstruction can be generally recommended. PMID:16337796

Coury, H J C G; Brasileiro, J S; Salvini, T F; Poletto, P R; Carnaz, L; Hansson, G A

2005-12-07

375

Candidate Exercise Technologies and Prescriptions.  

National Technical Information Service (NTIS)

This slide presentation reviews potential exercise technologies to counter the effects of space flight. It includes a overview of the exercise countermeasures project, a review of some of the candidate exercise technologies being considered and a few of t...

L. H. Loerch

2010-01-01

376

77 FR 52742 - Public Meeting-Strengthening the National Medical Device Postmarket Surveillance System; Request...  

Federal Register 2010, 2011, 2012, 2013

...Strengthening the National Medical Device Postmarket Surveillance System...Strengthening the National Medical Device Postmarket Surveillance System...public feedback regarding the medical device postmarket surveillance...

2012-08-30

377

Insulin therapy and exercise.  

PubMed

Medical nutrition therapy and physical exercise are the cornerstones of the diabetes management. Patients with type 1 DM always need exogenous insulin administration, recently available in the form of insulin analogs. In type 2 DM, characterized by increased insulin resistance and progressive decline of the beta-cell function, various antidiabetic medications are used. Most of the subjects with type 2 DM will finally need insulin. The main site of insulin action is the skeletal muscle, while the liver is the main site of glucose storage in the form of glycogen. With the modern diabetes therapies it is possible to rapidly reach and maintain normoglycemia in both types of DM but with the cost of higher incidence of hypoglycemia, especially related to exercise. Regular physical exercise causes a lot of beneficial effects in healthy as well as diabetic subjects of all age groups. In type 1 DM physical exercise is a fundamental element for both physical and mental development. In type 2 DM it has a main role in diabetes control. The increased hepatic glucose production and the increased muscular glucose uptake during exercise are closely interrelated in all exercise intensities. In diabetes mellitus there is a disturbed energy substrate use during exercise leading to either hypo- or hyperglycemia. The influence of low or moderate intensity aerobic exercise on diabetes control has been well studied. The inappropriately high insulinemia combined with the low glucose levels can lead to severe hypoglycemia if proper measures are not taken. Prolonged exercise can also predispose to decreased glucose counter regulation. It is better for the type 1 diabetic subject to postpone the exercise session in very high (>300 mg/dl) or very low (<70 mg/dl) BG levels. Every insulin treated subject is recommended to be checked for any existing diabetic complication before the start of every exercise program. Glucose measurement with glucose meters or sometimes with Continuous Glucose Monitoring System (CGMS) must be made before, during and most importantly after the end of the exercise session. It is recommended either to reduce or suspend the previous insulin dose depending on the insulin regime or to receive extra carbohydrates before, during or after the exercise session or both. Subjects with type 1 DM may participate at almost all the competitive sports if precautions are taken. These measures must be individualized and readjusted, even empirically. In very high intensity exercise (about 80% of VO(2 max)) or when high intensity exercise follows a low intensity one, there is a tendency of the BG to increase due to excessive circulating catecholamines necessitating postexercise short acting insulin. In anaerobic or resistance exercise lactic acid is produced. This exercise type is recommended for people in whom aerobic exercise is contraindicated. These two exercise types can be combined. The incidence of hypoglycemia or hyperglycemia in specific forms of resistance exercise as well as the appropriate insulin dose adjustment are not well studied. In conclusion all exercise types are beneficial for both types of diabetes. PMID:21864755

Kourtoglou, Georgios I

2011-08-01

378

Contralateral muscle fatigue in human quadriceps muscle: evidence for a centrally mediated fatigue response and cross-over effect  

Microsoft Academic Search

The purpose of this investigation was to examine the effects of voluntary muscular fatigue in one lower limb and determine whether a ‘cross-over’ of fatigue is evident in the contralateral limb. Twenty-eight subjects (13 males and 15 females) performed a series of voluntary and evoked isometric contractions of both the dominant (exercised) and non-dominant (non-exercised) leg extensor muscles, prior to

Jodie Rattey; Peter G. Martin; Derek Kay; Jack Cannon; Frank E. Marino

2006-01-01

379

Exercise through Menopause.  

ERIC Educational Resources Information Center

|Menopause is associated with many different health effects and symptoms. This paper explains that regular exercise can play a critical role in protecting health and battling the increased risk of cardiovascular disease, osteoporosis, pelvic floor atrophy, and joint stiffness associated with menopause. Exercise programs for menopausal women should…

Stuhr, Robyn M.

2002-01-01

380

Muscle growth and exercise  

Microsoft Academic Search

This paper first reviews muscle growth and then considers the influence of exercise in growth. Knowledge about how muscle cells grow and some factors that may influence the growth pattern are discussed first since these effects must be considered before the influence of exercise becomes clear. Growth of muscle can occur in three ways: (1) by an increase in muscle

A. M. Pearson

1990-01-01

381

Neurobiology of Exercise  

Microsoft Academic Search

Voluntary physical activity and exercise training can favorably influence brain plasticity by facilitating neurogenerative, neuroadaptive, and neuroprotective processes. At least some of the processes are mediated by neurotrophic factors. Motor skill training and regular exercise enhance executive functions of cognition and some types of learning, including motor learning in the spinal cord. These adaptations in the central nervous system have

Rod K. Dishman; Hans-Rudolf Berthoud; Frank W. Booth; Carl W. Cotman; V. Reggie Edgerton; Monika R. Fleshner; Simon C. Gandevia; Fernando Gomez-Pinilla; Benjamin N. Greenwood; Charles H. Hillman; Arthur F. Kramer; Barry E. Levin; Timothy H. Moran; Amelia A. Russo-Neustadt; John D. Salamone; Jacqueline D. Van Hoomissen; Charles E. Wade; David A. York; Michael J. Zigmond

2006-01-01

382

Exercise Against Depression.  

ERIC Educational Resources Information Center

|Physical activity is useful for preventing and easing depression symptoms. When prescribing exercise as an adjunct to medication and psychotherapy, physicians must consider each patient's individual circumstances. Hopelessness and fatigue can make physical exercise difficult. A feasible, flexible, and pleasurable program has the best chance for…

Artal, Michal; Sherman, Carl

1998-01-01

383

Lab Exercises for Kinesiology.  

ERIC Educational Resources Information Center

This monograph presents descriptions of various exercises and athletic activities with a kinesiological and biomechanical analysis of the muscle systems involved. It is intended as examples of laboratory activities and projects in a college course in kinesiology. A listing of the required laboratory exercises precedes the examples. Specific…

Mills, Brett D.; And Others

384

Lab Exercises for Kinesiology.  

ERIC Educational Resources Information Center

|This monograph presents descriptions of various exercises and athletic activities with a kinesiological and biomechanical analysis of the muscle systems involved. It is intended as examples of laboratory activities and projects in a college course in kinesiology. A listing of the required laboratory exercises precedes the examples. Specific…

Mills, Brett D.; And Others

385

Exercise Against Depression.  

ERIC Educational Resources Information Center

Physical activity is useful for preventing and easing depression symptoms. When prescribing exercise as an adjunct to medication and psychotherapy, physicians must consider each patient's individual circumstances. Hopelessness and fatigue can make physical exercise difficult. A feasible, flexible, and pleasurable program has the best chance for…

Artal, Michal; Sherman, Carl

1998-01-01

386

Realism in Exercises.  

National Technical Information Service (NTIS)

The purpose of this study was to examine the process of command post exercises and the logistics realism associated with them. The research had several objectives: to identify problems in obtaining realism in exercises; to pose possible solutions to the p...

S. J. Hagel

1989-01-01

387

Osteoarthritis, osteoporosis, and exercise.  

PubMed

With the aging of the work force, occupational health nurses must prepare for encounters with clients who are challenged by osteoarthritis or osteoporosis. Clients should be encouraged to exercise safely to promote functioning at home and work. This article reviews recent literature on the benefits of exercise for workers with osteoarthritis, osteoporosis, or both. PMID:22938810

Garrison, Deborah

2012-09-01

388

Exercise in the cold  

Microsoft Academic Search

Exercising in the cold is not an attractive option for many athletes; however, defining what represents cold is difficult and is not standard for all events. If the exercise is prolonged and undertaken at a moderate intensity, environmental temperatures around 11°C can be an advantage. If the intensity is lower than this value and the individual does not generate sufficient

Myra Nimmo

2004-01-01

389

Exercise and functional foods  

PubMed Central

Appropriate nutrition is an essential prerequisite for effective improvement of athletic performance, conditioning, recovery from fatigue after exercise, and avoidance of injury. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. In addition, several natural food components have been found to show physiological effects, and some of them are considered to be useful for promoting exercise performance or for prevention of injury. However, these foods should only be used when there is clear scientific evidence and with understanding of the physiological changes caused by exercise. This article describes various "functional foods" that have been reported to be effective for improving exercise performance or health promotion, along with the relevant physiological changes that occur during exercise.

Aoi, Wataru; Naito, Yuji; Yoshikawa, Toshikazu

2006-01-01

390

Exercise and functional foods.  

PubMed

Appropriate nutrition is an essential prerequisite for effective improvement of athletic performance, conditioning, recovery from fatigue after exercise, and avoidance of injury. Nutritional supplements containing carbohydrates, proteins, vitamins, and minerals have been widely used in various sporting fields to provide a boost to the recommended daily allowance. In addition, several natural food components have been found to show physiological effects, and some of them are considered to be useful for promoting exercise performance or for prevention of injury. However, these foods should only be used when there is clear scientific evidence and with understanding of the physiological changes caused by exercise. This article describes various "functional foods" that have been reported to be effective for improving exercise performance or health promotion, along with the relevant physiological changes that occur during exercise. PMID:16749944

Aoi, Wataru; Naito, Yuji; Yoshikawa, Toshikazu

2006-06-05

391

Exercise interventions: defusing the world's osteoporosis time bomb.  

PubMed

Osteoporosis is a major public health problem, affecting millions of people worldwide. The associated health care costs are growing in parallel with increases in elderly populations, and it is expected that the number of osteoporotic fractures will double over the next 50 years. The best way to address osteoporosis is prevention. Some interventions to maximize and preserve bone mass have multiple health benefits and are cost-effective. For example, modifications to diet and lifestyle can help to prevent osteoporosis, and could potentially lead to a significant decrease in fracture rates; and exercise is a valuable adjunct to programmes aimed at alleviating the risks and symptoms of osteoporosis. Practising exercise at a young age helps maximize the mineral density of bones while they are still growing and maturing, and continuing to excercise minimizes bone loss later in life. Not only does exercise improve bone health, it also increases muscle strength, coordination, balance, flexibility and leads to better overall health. Walking, aerobic exercise, and t'ai chi are the best forms of exercise to stimulate bone formation and strengthen the muscles that help support bones. Encouraging physical activity at all ages is therefore a top priority to prevent osteoporosis. PMID:14758410

Kai, Ming Chan; Anderson, Mary; Lau, Edith M C

2004-01-20

392

VASP involvement in force-mediated adherens junction strengthening  

PubMed Central

Strengthening of cell-matrix adhesions in response to applied force has been well-documented. However, while implied by various lines of evidence, the force-mediated strengthening of cell-cell adhesions has not been directly demonstrated. In the current study, we present results consistent with force strengthening in adherens junctions, obtained by application of different force profiles to VE-cadherin coated magnetic beads attached to endothelial cells. When force is ramped from a low to high value over time, fewer beads detach than with the immediate application of high force. Cells treated with cytochalasin D or lacking Ena/VASP activity show similar levels of detachment relative to controls, but force strengthening is lost. Further, cells overexpressing VASP show stronger adhesion in response to low and high force, but adhesion weakening in response to ramped forces. These results indicate that force-mediated adhesion strengthening occurs in endothelial adherens junctions and that dynamic VASP activity is necessary for this process.

Kris, Anita; Kamm, Roger D.; Sieminski, Alisha L.

2008-01-01

393

Exercise induced pulmonary vasoconstriction.  

PubMed Central

Pulmonary vascular resistance normally falls or remains unchanged during exercise. Seven children with pulmonary hypertension were exercised during cardiac catheterisation after operative correction of ventricular septal defect (6) and truncus arteriosus (1). Except for the presence of moderate pulmonary hypertension, resting haemodynamics in these seven children were similar to those of normal children of equal age, but during exercise the postoperative patients showed a rise rather than a fall (+2% vs -18%) in total pulmonary vascular resistance. Two of the seven children had a substantial increase in pulmonary arteriolar resistance during exercise (from 509 to 715 dyne s cm-5 in one patient and from 606 to 828 dyne s cm-5 in the other). These two patients did not differ from normal children in respect of arterial or mixed venous oxygen saturations or of pH with exercise, nor was left atrial pressure related to the rise in pulmonary resistance. These two patients, however, had only a small rise in cardiac output during exercise (6.8% and 43.1%) in spite of a substantial increase in oxygen consumption (121% and 373%). One of the patients with exercise-induced pulmonary vasoconstriction had an 82% increase in resting pulmonary vascular resistance over a five year period subsequent to her first exercise study. Analysis of these data, and those previously reported, suggests that exercise induced pulmonary vasoconstriction may occur in 10 to 25% of patients who survive correction of certain congenital cardiac defects. The vasoconstriction cannot be attributed to abnormal changes in blood gases or left atrial pressure, and may be an early sign of progressive pulmonary hypertension.

Kulik, T J; Bass, J L; Fuhrman, B P; Moller, J H; Lock, J E

1983-01-01

394

Geologic Mapping Exercise  

NSDL National Science Digital Library

This exercise is designed to simulate how a basic geological investigation of a site takes place. A basic geological investigation includes familiarizing yourself with the unconsolidated sediments, rocks, structural geology, and groundwater present at your site. As part of this exercise you will have to properly identify a variety of rock types and sediments, create maps that represent data you collected at each location, and complete a basic report of your findings (optional). Once completed, this exercise should give students a basic understanding of how the various concepts used throughout the semester are applied in the real world in the form of a geological investigation.

Smith, Andrew

395

Isokinetic hamstrings-to-quadriceps peak torque ratio: the influence of sport modality, gender, and angular velocity.  

PubMed

The purpose of this study was to determine differences in hamstrings-to-quadriceps (H/Q) peak torque ratios evaluated at different angular velocities between men and women who participate in judo, handball or soccer. A total of 166 athletes, including 58 judokas (26 females and 32 males), 39 handball players (22 females and 17 males), and 69 soccer players (17 females and 52 males), were evaluated using an isokinetic dynamometer. The H/Q isokinetic peak torque ratios were calculated at angular velocities of 1.05 rad · s?¹ and 5.23 rad · s?¹. In the analysis by gender, female soccer players produced lower H/Q peak torque ratios at 1.05 rad · s?¹ than males involved in the same sport. However, when H/Q peak torque ratio was assessed at 5.23 rad · s?¹, there were no significant differences between the sexes. In the analysis by sport, there were no differences among females at 1.05 rad · s?¹. In contrast, male soccer players had significantly higher H/Q peak torque ratios than judokas (66 ± 12% vs. 57 ± 14%, respectively). Female handball players produced significantly lower peak torque ratios at 5.23 rad · s?¹ than judokas or soccer players, whereas males presented no ratio differences among sports At 5.23 rad · s?¹. In the analysis by velocity, women's muscular ratios assessed at 1.05 rad · s?¹ were significantly lower than at 5.23 rad · s?¹ for all sports; among men, only judokas presented lower ratios at 1.05 rad · s?¹ than at 5.23 rad · s?¹. The present results suggest that sport modality and angular velocity influence the isokinetic strength profiles of men and women. PMID:22364375

Andrade, Marilia Dos Santos; De Lira, Claudio Andre Barbosa; Koffes, Fabiana De Carvalho; Mascarin, Naryana Cristina; Benedito-Silva, Ana Amélia; Da Silva, Antonio Carlos

2012-01-01

396

Molecular profiles of Quadriceps muscle in myostatin-null mice reveal PI3K and apoptotic pathways as myostatin targets  

PubMed Central

Background Myostatin (MSTN), a member of the TGF-? superfamily, has been identified as a negative regulator of skeletal muscle mass. Inactivating mutations in the MSTN gene are responsible for the development of a hypermuscular phenotype. In this study, we performed transcriptomic and proteomic analyses to detect altered expression/abundance of genes and proteins. These differentially expressed genes and proteins may represent new molecular targets of MSTN and could be involved in the regulation of skeletal muscle mass. Results Transcriptomic analysis of the Quadriceps muscles of 5-week-old MSTN-null mice (n = 4) and their controls (n = 4) was carried out using microarray (human and murine oligonucleotide sequences) of 6,473 genes expressed in muscle. Proteomic profiles were analysed using two-dimensional gel electrophoresis coupled with mass spectrometry. Comparison of the transcriptomic profiles revealed 192 up- and 245 down- regulated genes. Genes involved in the PI3K pathway, insulin/IGF pathway, carbohydrate metabolism and apoptosis regulation were up-regulated. Genes belonging to canonical Wnt, calcium signalling pathways and cytokine-receptor cytokine interaction were down-regulated. Comparison of the protein profiles revealed 20 up- and 18 down-regulated proteins spots. Knockout of the MSTN gene was associated with up-regulation of proteins involved in glycolytic shift of the muscles and down-regulation of proteins involved in oxidative energy metabolism. In addition, an increased abundance of survival/anti-apoptotic factors were observed. Conclusion All together, these results showed a differential expression of genes and proteins related to the muscle energy metabolism and cell survival/anti-apoptotic pathway (e.g. DJ-1, PINK1, 14-3-3? protein, TCTP/GSK-3?). They revealed the PI3K and apoptotic pathways as MSTN targets and are in favour of a role of MSTN as a modulator of cell survival in vivo.

Chelh, Ilham; Meunier, Bruno; Picard, Brigitte; Reecy, Mark James; Chevalier, Catherine; Hocquette, Jean-Francois; Cassar-Malek, Isabelle

2009-01-01

397

DESIGN OF CONTINUOUS FRP-STRENGTHENED CONCRETE STRUCTURES ALLOWING MOMENT REDISTRIBUTION  

Microsoft Academic Search

The use of fiber-reinforced polymer (FRP) composites is now a widely-accepted solution for the strengthening of reinforced concrete structures. FRP strengthening schemes offer many well- documented benefits for the retrofit of many existing concrete buildings and bridges. However, the main drawback in using FRP for such purposes is the reduction in ductility that the strengthened structure displays after strengthening. This

Tim Ibell; Pedro Silva

398

Effects of acute exercise on attenuated vagal baroreflex function during bed rest.  

PubMed

We measured carotid baroreceptor-cardiac reflex responses in six healthy men, 24 h before and 24 h after a bout of leg exercise during 6 degrees head-down bed rest to determine if depressed vagal baroreflex function associated with exposure to microgravity environments could be reversed by a single exposure to acute intense exercise. Baroreflex responses were measured before bed rest and on day 7 of bed rest. An exercise bout consisting of dynamic and isometric actions of the quadriceps at graded speeds and resistances was performed on day 8 of bed rest and measurements of baroreflex response were repeated 24 h later. Vagally-mediated cardiac responses were provoked with ramped neck pressure-suction sequences comprising pressure elevations to +40 mm Hg, followed by serial, R-wave triggered 15 mm Hg reductions, to -65 mm Hg. Baroreceptor stimulus-cardiac response relationships were derived by plotting each R-R interval as a function of systolic pressure less the neck chamber pressure applied during the interval. Compared with pre-bed rest baseline measurements, 7 d of bed rest decreased the gain (maximum slope) of the baroreflex stimulus-response relationship by 16.8 +/- 3.4% (p < 0.05). On day 9 of bed rest, 24 h after exercise, the maximum slope of the baroreflex stimulus-response relationship was increased (p < 0.05) by 10.7 +/- 3.7% above pre-bed rest levels and 34.3 +/- 7.9% above bed rest day 7. Our data verify that vagally-mediated baroreflex function is depressed by exposure to simulated microgravity and demonstrate that this effect can be acutely reversed by exposure to a single bout of intense exercise. PMID:1445165

Convertino, V A; Doerr, D F; Guëll, A; Marini, J F

1992-11-01

399

Menstrual cycle, exercise and health  

Microsoft Academic Search

Exercise training can have an impact on the menstrual cycle. If the exercise load is great enough it can lead to irregular or even the complete absence of menses, which has implications for reproductive health. Conversely, the menstrual cycle can affect exercise performance. Disruptions in hormonal balance throughout the menstrual cycle have been implicated in altered muscular strength, exercise endurance

Ellen A. Dawson; Thomas Reilly

2009-01-01

400

Embryo recovery from exercised mares  

Microsoft Academic Search

The effect of exercise on mare reproductive efficiency was evaluated by comparing rates of embryo recovery from mares assigned to either an exercise regimen or a non-exercise (control) regimen. Exercised mares were worked daily for 30min under average ambient conditions of >30°C and >50% humidity. Mares were inseminated during estrus and subjected to uterine flush for embryo recovery on d

C. J. Mortensen; Y. H. Choi; K. Hinrichs; N. H. Ing; D. C. Kraemer; S. G. Vogelsang; M. M. Vogelsang

2009-01-01

401

Effects of Estrogen Fluctuation during the Menstrual Cycle on the Response to Stretch-Shortening Exercise in Females  

PubMed Central

The aim of this study was to investigate whether variation in estrogen levels during the menstrual cycle influences susceptibility to exercise-induced muscle damage after stretch-shortening cycle exercise. Physically active women (n = 18; age = 20.2 ± 1.7?yr) participated in this research. The subjects performed one session of 100 maximal drop jumps on day 1 or 2 of the follicular phase and another identical session on day 1 or 2 of the ovulatory phase; the order of the sessions was randomized. Quadriceps femoris muscle peak torque evoked by electrical stimulation and maximal voluntary contraction, muscle pain, and CK activity were measured before and at various times up to 72?h after exercise. It was found that the high estrogen level during the ovulatory phase might be related to an earlier return to baseline muscle strength after strenuous stretch-shortening cycle exercise in that phase compared with the follicular phase. The estrogen effect appears to be highly specific to the damaged site because the differences in most EIMD markers (CK, soreness, and low-frequency fatigue) between the two menstrual cycle phases were small.

Sipaviciene, Saule; Daniuseviciute, Laura; Kliziene, Irina; Kamandulis, Sigitas; Skurvydas, Albertas

2013-01-01

402

Heat treatment for dispersion strengthened aluminum-base alloy  

SciTech Connect

A method is described for treating mechanically alloyed aluminum base alloys to increase stress corrosion resistance after heating of the aluminum-base alloy to a temperature between about 100 C and 150 C comprising the steps of: shaping a dispersion strengthened aluminum-base alloy consisting essentially of by weight percent about 0.5 to 3 lithium and about 0.5 to 7 magnesium to form an object of substantially final form; and heat treating said object strengthened aluminum-base alloy at a temperature and at least a minimum time sufficient to increase stress corrosion cracking resistance to at least 27 days in accordance with ASTM G44-88 for conditions arising from said dispersion strengthened aluminum-base alloy being exposed to temperatures between about 100 C and 150 C.

Crum, J.R.; Schelleng, R.D.; McEwen, J.; Weber, J.H.

1993-08-31

403

Seismic Strengthening of Carpentry Joints in Traditional Timber Structures  

SciTech Connect

The static and dynamic behavior of timber structures largely depends on their connections. In traditional timber construction, elements are usually connected with carpentry joints based on contact pressure and friction, often with only minor reinforcement generically intended to avoid disassembling. In current practice, interventions for the upgrading of carpentry joints are mainly based on empirical knowledge according to tradition. Often they produce a general strengthening of the connection, but are not specific for the case of seismic action. Strengthening on heuristic bases may be only partially effective or possibly disproportioned. The behavior of the carpentry joints most used in roof structures is examined. The birdsmouth joint, connecting rafters to the tie beam, has been studied first, characterizing its behavior numerically and experimentally in monotonic and cyclic conditions. Other forms of the rafter-to-tie connection, the double notch joint and the case of parallel rafters, are discussed. Some general criteria for the seismic strengthening of these joints are presented.

Parisi, Maria A.; Cordie, Cinzia [Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milano (Italy); Piazza, Maurizio [Universita degli studi di Trento, via Mesiano 77, 38050 Trento (Italy)

2008-07-08

404

Tetraspanin CD151 regulates ?6?1 integrin adhesion strengthening  

PubMed Central

The tetraspanin CD151 molecule associates specifically with laminin-binding integrins, including ?6?1. To probe strength of ?6?1-dependent adhesion to laminin-1, defined forces (0–1.5 nN) were applied to magnetic laminin-coated microbeads bound to NIH 3T3 cells. For NIH 3T3 cells bearing wild-type CD151, adhesion strengthening was observed, as bead detachment became more difficult over time. In contrast, mutant CD151 (with the C-terminal region replaced) showed impaired adhesion strengthening. Static cell adhesion to laminin-1, and detachment of beads coated with fibronectin or anti-?6 antibody were all unaffected by CD151 mutation. Hence, CD151 plays a key role in selectively strengthening ?6?1 integrin-mediated adhesion to laminin-1.

Lammerding, Jan; Kazarov, Alexander R.; Huang, Hayden; Lee, Richard T.; Hemler, Martin E.

2003-01-01

405

Adventures in Exercise Physiology  

NSDL National Science Digital Library

The author altered the format of an exercise physiology course from traditional lecture to emphasizing daily reading quizzes and group problem-solving activities. The SALGains evaluation was used to compare the two approaches and significant improvements

Fitzpatrick, Kathleen A.

2004-09-01

406

Adjustable aquatic exercise device  

US Patent & Trademark Office Database

This new and unique adjustable cantilevered aquatic exercise device offers a clean modern appearing device for exercising on the side of a swimming pool or from the end of a diving board. By mounting two extension arms to two horizontal support arms connected and mounted to the pool deck surface by mounting plates, angle-mounting brackets or slid over the end of the diving board, a single exercise bar may be relocated between pluralities of orifices on the extension arms to achieve a wide variety of elevations to exercise at the side of a swimming pool. This device can be pivoted back from the edge of the pool and remains completely out of the water when in use, not requiring the need to be constructed from expensive materials, and may be finished with a wide variety of rust preventative and cushioned coatings.

Checketts; Stanley J. (Providence, UT)

2008-03-18

407

Rotator cuff exercises  

MedlinePLUS

... torn due to overuse or injury See also: Rotator cuff problems These injuries often lead to pain, weakness, and stiffness when you use your shoulder. A key part in your recovery is starting exercises to make the muscles and ...

408

Depression and Exercise  

Microsoft Academic Search

With the efficacy of antidepressants under a question mark, many depressed patients are turning to common sense remedies such as exercise. Increasing activity not only has physical effects that lift a depressive mood: it can be fun as well.

Jerome Sarris; David J Kavanagh; Robert U Newton

2008-01-01

409

Physical Activity (Exercise)  

MedlinePLUS

Home > Publications > Our publications > Our publications Publications Physical activity (exercise) fact sheet How can physical activity improve my health? How much physical activity should I do? How much physical activity do ...

410

Exercises in Applied Geochemistry  

ERIC Educational Resources Information Center

|Reviews exercises in the analysis of samples and interpretations of results from the geochemical survey portion of a three year teacher education program in geology presented at Salisbury College of Advanced Education. (SL)|

Shackleton, W. G.

1977-01-01

411

Exercise and pregnancy.  

PubMed

Exercise is an important component of a healthy lifestyle and, as such, is recommended during pregnancy. However, the response to exercise of both the expectant mother and fetus varies depending on the fitness level of the woman. The response to exercise is also affected by the known musculoskeletal and physiologic changes associated with pregnancy, such as increased ligament laxity, weight gain, change in the center of gravity, and carpal tunnel syndrome. Although the physiologic responses of the pregnant woman and fetus have been well studied, the literature contains comparatively few studies investigating response to exercise. When performed properly, activities such as aerobics, impact and nonimpact activities, resistance training, and swimming may be beneficial during pregnancy. PMID:19652032

DeMaio, Marlene; Magann, Everett F

2009-08-01

412

Oxide-dispersion strengthening of porous powder metalurgy parts  

DOEpatents

Oxide dispersion strengthening of porous metal articles includes the incorporation of dispersoids of metallic oxides in elemental metal powder particles. Porous metal articles, such as filters, are fabricated using conventional techniques (extrusion, casting, isostatic pressing, etc.) of forming followed by sintering and heat treatments that induce recrystallization and grain growth within powder grains and across the sintered grain contact points. The result is so-called "oxide dispersion strengthening" which imparts, especially, large increases in creep (deformation under constant load) strength to the metal articles.

Judkins, Roddie R. (Knoxville, TN)

2002-01-01

413

Mechanical properties of oxide dispersion strengthened (ODS) molybdenum alloys  

SciTech Connect

Oxide dispersion strengthened molybdenum, Mo-ODS, developed by a proprietary powder metallurgy process, exhibits a creep rupture life at 0.65T{sub m} (1,600 C) of three to five orders of magnitude greater than unalloyed molybdenum, while maintaining ductile fracture behavior at temperatures significantly below room temperature. In comparison, the creep rupture life of the Mo-50Re solid solution strengthened alloy at 1,600 C is only an order of magnitude greater than unalloyed molybdenum. The results of microstructural characterization and thermal stability and mechanical property testing are discussed.

Bianco, R.; Buckman, R.W. Jr.

1998-03-01

414

Plume Delineation Exercise  

NSDL National Science Digital Library

This exercise is designed to develop students ability to synthesize subsurface data and develop a model to explain a local groundwater contamination issue. Based on their groundwater model, they will make predictions as to location of the source area and the location of any potential human health risk. The exercise requires basic contour mapping skill, simple mathematical problem solving skills and a knowledge of Darcy's Law. Has minimal/no quantitative component

Lev, Steven

415

Exercise and Rehabilitation  

Microsoft Academic Search

Most people in the UK and US do not get enough exercise. Children are not exercising asmuch as their parents or grandparents\\u000a did, and this is partly due to less emphasis placed on competitive sports in schools, today’s sedentary, lazy lifestyle of\\u000a watching TV and playing computer and video games, and less opportunities to participate in team sports.

Clive Handler; Gerry Coghlan

416

Inverted Trough Case Exercise  

NSDL National Science Digital Library

This exercise flollows the progression of a winter weather event across the Central Plains states beginning 1200 UTC on 7 March 1999. Each forecast question is accompanied by Eta model data and includes a forecast discussion by Phil Schumacher, NWS Sioux Falls, South Dakota. This exercise compliments the Webcast, Inverted Troughs and their Associated Precipitation Regimes, based on a presentation by Phil Schumacher at the MSC Winter Weather Course, December 2002, in Boulder Colorado.

Spangler, Tim

2004-01-01

417

PULMONARY CIRCULATION AT EXERCISE  

PubMed Central

The pulmonary circulation is a high flow and low pressure circuit, with an average resistance of 1 mmHg.min.L?1 in young adults, increasing to 2.5 mmHg.min.L?1 over 4–6 decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20–25 mmHg threshold associated with interstitial lung edema and altered ventilation/perfusion relationships. Pulmonary artery pressures of 40–50 mmHg, which can be achieved at maximal exercise, may correspond to the extreme of tolerable right ventricular afterload. Distension of capillaries that decrease resistance may be of adaptative value during exercise, but this is limited by hypoxemia from altered diffusion/perfusion relationships. Exercise in hypoxia is associated with higher pulmonary vascular pressures and lower maximal cardiac output, with increased likelihood of right ventricular function limitation and altered gas exchange by interstitial lung edema. Pharmacological interventions aimed at the reduction of pulmonary vascular tone have little effect on pulmonary vascular pressure-flow relationships in normoxia, but may decrease resistance in hypoxia, unloading the right ventricle and thereby improving exercise capacity. Exercise in patients with pulmonary hypertension is associated with sharp increases in pulmonary artery pressure and a right ventricular limitation of aerobic capacity. Exercise stress testing to determine multipoint pulmonary vascular pressures-flow relationships may uncover early stage pulmonary vascular disease.

NAEIJE, R; CHESLER, N

2012-01-01

418

Exercise and multiple sclerosis.  

PubMed

The pathophysiology of multiple sclerosis (MS) is characterised by fatigue, motor weakness, spasticity, poor balance, heat sensitivity and mental depression. Also, MS symptoms may lead to physical inactivity associated with the development of secondary diseases. Persons with MS are thus challenged by their disability when attempting to pursue an active lifestyle compatible with health-related fitness. Although exercise prescription is gaining favour as a therapeutic strategy to minimise the loss of functional capacity in chronic diseases, it remains under-utilised as an intervention strategy in the MS population. However, a growing number of studies indicate that exercise in patients with mild-to-moderate MS provides similar fitness and psychological benefits as it does in healthy controls. We reviewed numerous studies describing the responses of selected MS patients to acute and chronic exercise compared with healthy controls. All training studies reported positive outcomes that outweighed potential adverse effects of the exercise intervention. Based on our review, this article highlights the role of exercise prescription in the multidisciplinary approach to MS disease management for improving and maintaining functional capacity. Despite the often unpredictable clinical course of MS, exercise programmes designed to increase cardiorespiratory fitness, muscle strength and mobility provide benefits that enhance lifestyle activity and quality of life while reducing risk of secondary disorders. Recommendations for the evaluation of cardiorespiratory fitness, muscle performance and flexibility are presented as well as basic guidelines for individualised exercise testing and training in MS. Special considerations for exercise, including medical management concerns, programme modifications and supervision, in the MS population are discussed. PMID:15575796

White, Lesley J; Dressendorfer, Rudolph H

2004-01-01

419

Effect of exercise intensities on free fatty acid uptake in whole-body organs measured with (123)I-BMIPP-SPECT.  

PubMed

Our purpose was to evaluate the effects of exercise intensities on free fatty acid (FFA) uptake in skeletal muscles, myocardium and liver among humans using (123)I-labeled 15-(p-iodophenyl)-3-(R,S)-methyl-pentadecanoic acid ((123)I-BMIPP) and single photon emission computed tomography technique (SPECT). Six untrained male subjects were studied after 35 min of ergometer bicycle exercise at 40, 70 and 80% maximal aerobic power (VO(2max)) One subject was studied as resting control. SPECT scan was done 40 min after (123)I-BMIPP injection. Mean fractional uptake (FU) in quadriceps femoris muscle (QF) were 0.029 +/- 0.001, 0.029 +/- 0.002 and 0.025 +/- 0.002% at 40, 70 and 80% VO(2max), respectively. FU of QF at 40 and 70% VO(2max) were significantly higher than those of 80% VO(2max). Mean FU into myocardium were 0.048 +/- 0.002, 0.052 +/- 0.004 and 0.050 +/- 0.003% and those in liver were 0.033 +/- 0.002, 0.032 +/- 0.002 and 0.034 +/- 0.003% at each loads, respectively. Any significant changes were not suggestive in liver and myocardium after exercise. Mean FU (the mean values of all exercise intensity) at exercise is 2.86, 0.96 and 0.71 times higher than those at rest in QF, myocardium and liver. These results suggest: (1) in skeletal muscles, energy requirements at above lactate threshold at high exercise intensity predominantly depend upon other intramuscular energy substrates, (2) there is possibility of energy compensation by other substrates in myocardium at higher exercise intensity, (3) FFA uptake in liver might decrease after exercise; however, the influence of exercise intensities is not suggested. PMID:18654795

Kitada, Koji; Kubota, Kazuo; Nagatomi, Ryoichi; Itoh, Masatoshi; Tashiro, Manabu; Fukuda, Hiroshi; Masud, Mehedi; Fujimoto, Toshihiko

2008-07-25

420

Exercise and food factors.  

PubMed

Habitual exercise is beneficial to health as it improves metabolism, reduces the risk of cardiovascular disease, and maintains the immune system. Appropriate nutrition contributes to acceleration of health promotion due to exercise. Recommended daily allowance is elevated by physical activity and intake of various food factors such carbohydrates, proteins, vitamins, minerals, and other phytochemicals is required to avoid their shortage. Additional dietary food factors are effective not only in supplementation to satisfy the allowance but also in further acceleration of the benefits of fitness. Dietary nutrition is also important to maintain active function in the elderly by preventing aging-induced muscle atrophy and avoiding intense exercise-induced disorders. Recently, several food components have been found to show physiological effects, and some of them are considered to be useful for promoting or alternating the beneficial effects of exercise, maintaining homeostasis, and preventing muscle aging. However, some of these food factors should only be used when there is clear scientific evidence. Also, it is important to understand the physiological changes caused by exercise to use them correctly. This article describes various food factors that have been reported to be effective for improving health promotion, along with the relevant physiological changes that occur during exercise. PMID:19367119

Aoi, Wataru

2009-04-07

421

Exercise, Heart and Health  

PubMed Central

Regular physical activity provides a variety of health benefits, including improvement in cardiopulmonary or metabolic status, reduction of the risk of coronary artery disease or stroke, prevention of cancer, and decrease in total mortality. Exercise-related cardiac events are occasionally reported during highly competitive sports activity or vigorous exercises. However, the risk of sudden death is extremely low during vigorous exercise, and habitual vigorous exercise actually decreases the risk of sudden death during exercise. The cause of sudden death is ischemic in older subjects (?35 years old), while cardiomyopathies or genetic ion channel diseases are important underlying pathology in younger (<35 years old) victims. The subgroup of patients who are particularly at higher risk of exercise-related sudden death may be identified in different ways, such as pre-participation history taking, physical examination and/or supplementary cardiac evaluation. Limitations exist because current diagnostic tools are not sufficient to predict a coronary artery plaque with potential risk of disruption and/or an acute thrombotic occlusion. Proper and cost-effective methods for identification of younger subjects with cardiac structural problems or genetic ion channel diseases are still controversial.

2011-01-01

422

Electromyographical Comparison of Four Common Shoulder Exercises in Unstable and Stable Shoulders  

PubMed Central

This study examines if electromyographic (EMG) amplitude differences exist between patients with shoulder instability and healthy controls performing scaption, prone horizontal abduction, prone external rotation, and push-up plus shoulder rehabilitation exercises. Thirty nine subjects were categorized by a single orthopedic surgeon as having multidirectional instability (n = 10), anterior instability (n = 9), generalized laxity (n = 10), or a healthy shoulder (n = 10). Indwelling and surface electrodes were utilized to measure EMG activity (reported as a % of maximum voluntary isometric contraction (MVIC)) in various shoulder muscles during 4 common shoulder exercises. The exercises studied effectively activated the primary musculature targeted in each exercise equally among all groups. The serratus anterior generated high activity (50–80% MVIC) during a push-up plus, while the infraspinatus and teres major generated moderate-to-high activity (30–80% MVIC) during both the prone horizontal and prone external rotation exercises. Scaption exercise generated moderate activity (20–50% MVIC) in both rotator cuff and scapular musculature. Clinicians should feel confident in prescribing these shoulder-strengthening exercises in patients with shoulder instability as the activation levels are comparable to previous findings regarding EMG amplitudes and should improve the dynamic stabilization capability of both rotator cuff and scapular muscles using exercises designed to address glenohumeral joint instability.

Sciascia, Aaron; Kuschinsky, Nina; Nitz, Arthur J.; Mair, Scott D.; Uhl, Tim L.

2012-01-01

423

Electromyographical comparison of four common shoulder exercises in unstable and stable shoulders.  

PubMed

This study examines if electromyographic (EMG) amplitude differences exist between patients with shoulder instability and healthy controls performing scaption, prone horizontal abduction, prone external rotation, and push-up plus shoulder rehabilitation exercises. Thirty nine subjects were categorized by a single orthopedic surgeon as having multidirectional instability (n = 10), anterior instability (n = 9), generalized laxity (n = 10), or a healthy shoulder (n = 10). Indwelling and surface electrodes were utilized to measure EMG activity (reported as a % of maximum voluntary isometric contraction (MVIC)) in various shoulder muscles during 4 common shoulder exercises. The exercises studied effectively activated the primary musculature targeted in each exercise equally among all groups. The serratus anterior generated high activity (50-80% MVIC) during a push-up plus, while the infraspinatus and teres major generated moderate-to-high activity (30-80% MVIC) during both the prone horizontal and prone external rotation exercises. Scaption exercise generated moderate activity (20-50% MVIC) in both rotator cuff and scapular musculature. Clinicians should feel confident in prescribing these shoulder-strengthening exercises in patients with shoulder instability as the activation levels are comparable to previous findings regarding EMG amplitudes and should improve the dynamic stabilization capability of both rotator cuff and scapular muscles using exercises designed to address glenohumeral joint instability. PMID:22919499

Sciascia, Aaron; Kuschinsky, Nina; Nitz, Arthur J; Mair, Scott D; Uhl, Tim L

2012-08-07

424

The effects of McKenzie and Brunkow exercise program on spinal mobility comparative study.  

PubMed

This study encompassed 64 participants with symptoms of low back pain, 33 in McKenzie group and 31 in Brunkow group. Patients attended exercise program daily and they were asked to do the same exercise at home--five times a day in series of 5 to 10 repetition each time, depending of stage of disease and pain intensity. All patients were assessed for the spinal motion, before and after the treatment. All parameters for spinal movements showed improvement after exercising McKenzie program for lower back pain with a significant difference of p<0.01 for all motions. Also, in Brunkow group, all of the parameters showed statistically significant improvement at the end of treatment in relation to pre-treatment values, with significant difference of p<0.01 for all motions. Statistically comparison between McKenzie and Brunkow difference in score at the end of the treatment showed statistically significant improvement in McKenzie group, for extension, right and left side flexion, while flexion score didn't show statistically significant difference. McKenzie exercises seemed to be more effective than Brunkow exercises for improvement in spinal motion. Both, McKenzie and Brunkow exercises can be used for spinal mobility improvement in patients with lower back pain, but is preferable to use McKenzie exercises first, to decrease the pain and increase spinal mobility, and then Brunkow exercises to strengthen the paravertebral muscles. PMID:15628984

Muji? Skiki?, Emela; Trebinjac, Suad; Sakota, Slavica; Avdi?, Dijana

2004-02-01

425

Effets des ? 2-mimétiques inhalés, à doses thérapeutiques et juxtathérapeutiques, sur la force et la fatigabilité du quadriceps  

Microsoft Academic Search

Aims. – To evaluate the effects induced by the inhalation of mimetic beta on the muscular force.Synthesis of facts. – Increasing incidence of exercise-induced bronchoconstriction is observed in endurance athletes. This study refers to the potentially undue benefits of treatment used for this condition by ?2-agonists. High doses of these medications (p. o., 4 mg per pill) provide beneficial effects on

B. Wuyam; N. Decorte; I. Vivodtzev; V. Bricout; A. Favre-Juvin; M. Guinot; P. Flore

2005-01-01

426

Using Technology in Early Childhood Environments to Strengthen Cultural Connections  

ERIC Educational Resources Information Center

This article will discuss the use of technology with young children to strengthen cultural connections. A brief discussion of the use of technology in the field of Early Childhood Education and a brief discussion of diversity and cultural issues is followed by specific ways in which technology can be utilized to help young children understand…

Meadows, Mikki

2004-01-01

427

Promoting Competition to Strengthen Economic Growth in Belgium  

Microsoft Academic Search

Prices for many goods and services in Belgium are higher than in other countries, reflecting generally weak competitive pressures. The government has recently introduced several reforms to strengthen the competition policy framework. Nevertheless, to reap the full benefits of competitive markets, past reforms should be complemented with a number of further measures. The powers of the Competition Authority can still

Tomasz Kozluk

2009-01-01

428

Strengthening families through early intervention in high HIV prevalence countries  

Microsoft Academic Search

Families have been at the forefront of the response to the HIV\\/AIDS epidemic in high-prevalence countries. They have also borne the greatest costs associated with the epidemic, including impoverishment, which has strained their capacity to care for vulnerable members. Within this context, there is consensus that strengthening the capacity of families to care for children is one of the most

U. Chandan; L. Richter

2009-01-01

429

Strengthening of structures using carbon fibre\\/epoxy composites  

Microsoft Academic Search

Innovations in manufacturing and new technologies are based upon new materials and upon new applications which use materials already employed in other industries. This paper shows how high-performance fibre-reinforced composites, utilized for the last 25 years by the aircraft and space industries, may be employed to strengthen existing structures for civil engineering purposes.

U. Meier

1995-01-01

430

Development of Dispersion-Strengthened Nickel-Base Sheet Alloys.  

National Technical Information Service (NTIS)

Dispersion-Strengthened Ni-15Mo-ThO2 sheet was rolled from plate which was made by pressing, canning and extruding powders prepared by spray drying and selective reduction. Good ThO2 dispersions and strongly developed crystallographic textures were both n...

R. F. Cheney W. Scheithauer

1970-01-01

431

Fixing Steel Braced Frames to Concrete Structures for Earthquake Strengthening  

Microsoft Academic Search

Steel braced frames are widely used to upgrade concrete structures for earthquake loads. They are used both to strengthen the structure and to increase its ductility. In order to transfer the horizontal shear loads from the concrete structure to the steel braced frame, a reliable connection between the two is essential. It must be able to transfer the full capacity

Gilbert Balbuena; Jakob Kunz

432

Strengthening College Opportunity and Performance: Federal, State and Institutional Leadership  

ERIC Educational Resources Information Center

Leaders in all sectors--government, business, philanthropy--are calling on American colleges and universities to enroll and graduate more students to bolster the nation's economic competitiveness and to enhance its standard of living. The urgency of strengthening college opportunity informed President Obama's articulation of what amounts to a…

National Center for Public Policy and Higher Education, 2010

2010-01-01

433

Dilatant strengthening as a mechanism for slow slip events  

Microsoft Academic Search

The mechanics of slow slip events (SSE) in subduction zones remain unresolved. We suggest that SSE nucleate in areas of unstable friction under drained conditions, but as slip accelerates dilatancy reduces pore pressure p quenching instability. Competition between dilatant strengthening and thermal pressurization may control whether slip is slow or fast. We model SSE with 2-D elasticity, rate-state friction, and

Paul Segall; Allan M. Rubin; Andrew M. Bradley; James R. Rice

2010-01-01

434

Strengthening At-Risk and Homeless Young Mothers and Children  

ERIC Educational Resources Information Center

|The Strengthening At Risk and Homeless Young Mothers and Children Initiative, funded by the Conrad N. Hilton Foundation, aims to improve the housing, health, and development of homeless and at-risk young families. This article describes the services provided in four program sites (Pomona, CA; Antelope Valley, CA; Minneapolis, MN; and Chicago, IL)…

Medeiros, Debra; Vaulton, Wendy

2010-01-01

435

Brief Strategic Family Therapy. Family Strengthening Series. Juvenile Justice Bulletin.  

ERIC Educational Resources Information Center

|It is widely accepted that an increase in delinquency and violence is rooted in a number of interrelated social problems such as child abuse, alcohol and drug abuse, and youth conflict and aggression. Family strategies and interventions have been designed in an attempt to strengthen the role of the family within the community as a means to combat…

Robbins, Michael S.; Szapocznik, Jose

436

Shaking Table Tests Validating Two Strengthening Interventions on Masonry Buildings  

Microsoft Academic Search

Masonry buildings constitute quite often a precious cultural heritage for our cities. In order to future generations can enjoy this heritage, thence, effective projects of protection should be developed against all the anthropical and natural actions which may irreparably damage old masonry buildings. However, the strengthening interventions on these constructions have to respect their authenticity, without altering the original conception,

Gerardo de Canio; Giuseppe Muscolino; Alessandro Palmeri; Massimo Poggi; Paolo Clemente

2008-01-01

437

INNOVATIVE TECHNIQUE FOR STRENGTHENING RC BEAMS USING HYBRID FRP  

Microsoft Academic Search

In the last two decades, use of advanced composite materials such as Fiber Reinforced Polymers, (FRP), in strengthening reinforced concrete, (RC), structural elements have been increasing. Researches and design guidelines concluded that externally bonded FRP could increase the capacity of RC elements efficiently. However, the linear stress-strain characteristics of FRP up to failure and lack of yield plateau have a

Abdelhady Hosny; Hamdy Shaheen; Amr Abdelrahman

438

Performance of reinforced concrete beams strengthened by hybrid FRP laminates  

Microsoft Academic Search

In the last two decades, the use of advanced composite materials such as Fiber Reinforced Polymers (FRP) in strengthening reinforced concrete (RC) structural elements has been increasing. Research and design guidelines concluded that externally bonded FRP could increase the capacity of RC elements efficiently. However, the linear stress–strain characteristics of FRP up to failure and lack of yield plateau have

Abdelhady Hosny; Hamdy Shaheen; Amr Abdelrahman; Tamer Elafandy

2006-01-01

439

Strengthening Grief Support for Adolescents Coping with a Peer's Death  

ERIC Educational Resources Information Center

|This article offers suggestions for strengthening school-based grief support following an adolescent's death. Such interventions must be considered within the context of: (a) development during adolescence; (b) the role of peers in adolescent development; and (c) the fact that an adolescent peer's death is a non-normative life crisis in developed…

Balk, David E.; Zaengle, Donna; Corr, Charles A.

2011-01-01