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Sample records for knee extension isometric

  1. Effects of trunk stability on isometric knee extension muscle strength measurement while sitting.

    PubMed

    Hirano, Masahiro; Gomi, Masahiro; Katoh, Munenori

    2016-09-01

    [Purpose] This study aimed to investigate the effect of trunk stability on isometric knee extension muscle strength measurement while sitting by performing simultaneous measurements with a handheld dynamometer (HHD) and an isokinetic dynamometer (IKD) in the same seated condition. [Subjects and Methods] The subjects were 30 healthy volunteers. Isometric knee extension muscle strength was simultaneously measured with a HHD and an IKD by using an IKD-specific chair. The measurement was performed twice. Measurement instrument variables and the number of measurements were examined by using the analysis of variance and correlation tests. [Results] The measurement instrument variables and the number of measurements were not significantly different. The correlation coefficients between the HHD and IKD measurements were ≥0.96. [Conclusion] Isometric knee extension muscle strength measurement using the HHD in the sitting position resulted in a lower value than that using the IKD, presumably because of the effect of trunk stability on the measurement. In the same seated posture with trunk stability, no significant difference in measurement values was observed between the HHD and IKD. The present findings suggest that trunk stability while seated during isometric knee extension muscle strength measurement influenced the HHD measurement.

  2. Isometric knee extension force measured using a handheld dynamometer with and without belt-stabilization.

    PubMed

    Bohannon, Richard W; Kindig, Jeffrey; Sabo, Gregory; Duni, Allison E; Cram, Peter

    2012-10-01

    Although evidence suggests that tester strength limits the magnitude of isometric force that can be measured using a handheld dynamometer (HHD), previous studies have not investigated the actual limits of force magnitude that can be measured by trained testers when a belt is or is not used to stabilize the dynamometer. Therefore, the primary aims of this study were to determine: 1) the magnitude of knee extension forces that could be measured with a HHD with and without belt-stabilization and 2) the relationship between tester characteristics and knee extension strength measured with and without belt-stabilization. The characteristics of 20 trained testers (10 men, 10 women) were determined. Thereafter, they measured isometric knee extension strength using the MicroFET HHD with and without belt-stabilization. Paired t-tests were used to compare maximal knee extension forces under two conditions. Pearson product-moment correlations were calculated to determine the relationship between tester characteristics and knee extension forces measured under the two conditions. Knee extension forces (Newtons) measured using the HHD without belt-stabilization (470.6 ± 179.8) were significantly lower (t= -7.968, p<0.001) than those measured with belt-stabilization (866.9 ± 131.7). Pearson correlations between tester characteristics and knee extension forces measured with no belt-stabilization were all statistically significant (p ≤ 0.002); however, the correlations were not statistically significant under the belt-stabilization condition. The forces that can be measured with a HHD are higher than those suggested by previous researchers. By rectifying limitations imposed by tester strength, use of a belt allows very high knee extension forces to be measured.

  3. Mechanical correction of dynamometer moment for the effects of segment motion during isometric knee-extension tests.

    PubMed

    Tsaopoulos, Dimitrios E; Baltzopoulos, Vasilios; Richards, Paula J; Maganaris, Constantinos N

    2011-07-01

    The purpose of this study was to determine the effect of dynamometer and joint axis misalignment on measured isometric knee-extension moments using inverse dynamics based on the actual joint kinematic information derived from the real-time X-ray video and to compare the errors when the moments were calculated using measurements from external anatomical surface markers or obtained from the isokinetic dynamometer. Six healthy males participated in this study. They performed isometric contractions at 90° and 20° of knee flexion, gradually increasing to maximum effort. For the calculation of the actual knee-joint moment and the joint moment relative to the knee-joint center, determined using the external marker, two free body diagrams were used of the Cybex arm and the lower leg segment system. In the first free body diagram, the mean center of the circular profiles of the femoral epicondyles was used as the knee-joint center, whereas in the second diagram, the joint center was assumed to coincide with the external marker. Then, the calculated knee-joint moments were compared with those measured by the dynamometer. The results indicate that 1) the actual knee-joint moment was different from the dynamometer recorded moment (difference ranged between 1.9% and 4.3%) and the moment calculated using the skin marker (difference ranged between 2.5% and 3%), and 2) during isometric knee extension, the internal knee angle changed significantly from rest to the maximum contraction state by about 19°. Therefore, these differences cannot be neglected if the moment-knee-joint angle relationship or the muscle mechanical properties, such as length-tension relationship, need to be determined.

  4. Increase in rate of force development with skin cooling during isometric knee extension.

    PubMed

    Shimose, Ryota; Ushigome, Nobuyuki; Tadano, Chigaya; Sugawara, Hitoshi; Yona, Masae; Matsunaga, Atsuhiko; Muro, Masuo

    2014-12-01

    Rate of force development (RFD) plays an important role when performing rapid and forceful movements. Cold-induced afferent input with transient skin cooling (SC) can modulate neural drive. However, the relationship between RFD and SC is unknown. The purpose of this study was to investigate whether SC increases RFD during isometric knee extension. Fifteen young healthy men (25 ± 8 yrs old) contracted their quadriceps muscle as fast and forcefully as possible with or without SC. Skin cooling was administered to the front of the thigh. Torque and electromyographic activity were measured simultaneously. Peak torque was not affected by SC. Skin cooling induced a significant increase in RFD at the phase 0-30 and 0-50 ms. The root mean square of the electromyography of vastus medialis, rectus femoris and vastus lateralis at the phases 0-30-50-100 ms increased significantly or tended to increase with SC. These results suggest that SC may increase neural drive and improve RFD in the very early phases of contraction.

  5. Knee extension isometric torque production differences based on verbal motivation given to introverted and extroverted female children.

    PubMed

    McWhorter, J Wesley; Landers, Merrill; Young, Daniel; Puentedura, E Louie; Hickman, Robbin A; Brooksby, Candi; Liveratti, Marc; Taylor, Lisa

    2011-08-01

    To date, little research has been conducted to test the efficacy of different forms of motivation based on a female child's personality type. The purpose of this study was to evaluate the ability of female children to perform a maximal knee extension isometric torque test with varying forms of motivation, based on the child's personality type (introvert vs. extrovert). The subjects were asked to perform a maximal isometric knee extension test under three different conditions: 1) with no verbal motivation, 2) with verbal motivation from the evaluator only, and 3) with verbal motivation from a group of their peers and the evaluator combined. A 2×3 mixed ANOVA was significant for an interaction (F 2,62=17.530; p<0.0005). Post hoc testing for the introverted group showed that scores without verbal motivation were significantly higher than with verbal motivation from the evaluator or the evaluator plus the peers. The extroverted group revealed that scores with verbal motivation from the evaluator or the evaluator plus the peers were significantly higher than without verbal motivation. Results suggest that verbal motivation has a varying effect on isometric knee extension torque production in female children with different personality types. Extroverted girls perform better with motivation, whereas introverted girls perform better without motivation from others.

  6. Estimations of One Repetition Maximum and Isometric Peak Torque in Knee Extension Based on the Relationship Between Force and Velocity.

    PubMed

    Sugiura, Yoshito; Hatanaka, Yasuhiko; Arai, Tomoaki; Sakurai, Hiroaki; Kanada, Yoshikiyo

    2016-04-01

    We aimed to investigate whether a linear regression formula based on the relationship between joint torque and angular velocity measured using a high-speed video camera and image measurement software is effective for estimating 1 repetition maximum (1RM) and isometric peak torque in knee extension. Subjects comprised 20 healthy men (mean ± SD; age, 27.4 ± 4.9 years; height, 170.3 ± 4.4 cm; and body weight, 66.1 ± 10.9 kg). The exercise load ranged from 40% to 150% 1RM. Peak angular velocity (PAV) and peak torque were used to estimate 1RM and isometric peak torque. To elucidate the relationship between force and velocity in knee extension, the relationship between the relative proportion of 1RM (% 1RM) and PAV was examined using simple regression analysis. The concordance rate between the estimated value and actual measurement of 1RM and isometric peak torque was examined using intraclass correlation coefficients (ICCs). Reliability of the regression line of PAV and % 1RM was 0.95. The concordance rate between the actual measurement and estimated value of 1RM resulted in an ICC(2,1) of 0.93 and that of isometric peak torque had an ICC(2,1) of 0.87 and 0.86 for 6 and 3 levels of load, respectively. Our method for estimating 1RM was effective for decreasing the measurement time and reducing patients' burden. Additionally, isometric peak torque can be estimated using 3 levels of load, as we obtained the same results as those reported previously. We plan to expand the range of subjects and examine the generalizability of our results.

  7. Skinfold thickness affects the isometric knee extension torque evoked by Neuromuscular Electrical Stimulation

    PubMed Central

    Medeiros, Flávia V. A.; Vieira, Amilton; Carregaro, Rodrigo L.; Bottaro, Martim; Maffiuletti, Nicola A.; Durigan, João L. Q.

    2015-01-01

    BACKGROUND: Subcutaneous adipose tissue may influence the transmission of electrical stimuli through to the skin, thus affecting both evoked torque and comfort perception associated with neuromuscular electrical stimulation (NMES). This could seriously affect the effectiveness of NMES for either rehabilitation or sports purposes. OBJECTIVE: To investigate the effects of skinfold thickness (SFT) on maximal NMES current intensity, NMES-evoked torque, and NMES-induced discomfort. METHOD: First, we compared NMES current intensity, NMES-induced discomfort, and NMES-evoked torque between two subgroups of subjects with thicker (n=10; 20.7 mm) vs. thinner (n=10; 29.4 mm) SFT. Second, we correlated SFT to NMES current intensity, NMES-induced discomfort, and NMES-evoked knee extension torque in 20 healthy women. The NMES-evoked torque was normalized to the maximal voluntary contraction (MVC) torque. The discomfort induced by NMES was assessed with a visual analog scale (VAS). RESULTS: NMES-evoked torque was 27.5% lower in subjects with thicker SFT (p=0.01) while maximal current intensity was 24.2% lower in subjects with thinner SFT (p=0.01). A positive correlation was found between current intensity and SFT (r=0.540, p=0.017). A negative correlation was found between NMES-evoked torque and SFT (r=-0.563, p=0.012). No significant correlation was observed between discomfort scores and SFT (rs=0.15, p=0.53). CONCLUSION: These results suggest that the amount of subcutaneous adipose tissue (as reflected by skinfold thickness) affected NMES current intensity and NMES-evoked torque, but had no effect on discomfort perception. Our findings may help physical therapists to better understand the impact of SFT on NMES and to design more rational stimulation strategies. PMID:26647748

  8. Reliability of Concentric, Eccentric and Isometric Knee Extension and Flexion when using the REV9000 Isokinetic Dynamometer.

    PubMed

    de Carvalho Froufe Andrade, Alberto César Pereira; Caserotti, Paolo; de Carvalho, Carlos Manuel Pereira; de Azevedo Abade, Eduardo André; da Eira Sampaio, António Jaime

    2013-01-01

    The aim of this study was to assess the reliability of isokinetic and ISO knee extensor and flexor muscle strength when using the REV9000 (Technogym) isokinetic dynamometer. Moreover, the reliability of several strength imbalance indices and bilateral ratios were also examined. Twenty-four physically active healthy subjects (age 23±3 years) underwent three testing sessions, two on the same day and a third, 7 days later. All sessions proceeded in the same order: five concentric contractions at 60ºs-1 followed by an isometric contraction (5 seconds) and five eccentric contractions (60ºs-1). The results of this study showed a high reproducibility in eccentric (0.95-0.97), concentric (0.95-0.96) and isometric (0.93-0.96), isokinetic strength for knee extensor and flexor muscles, thus indicating that the REV9000 isokinetic dynamometer can be used in future sports performance studies. A low-to-moderate reliability was found in the isokinetic strength bilateral ratios while the Hamstring:Quadricep concentric ratio showed moderate reliability. The highest reliability (>0.90) was observed in the dynamic control ratio (Hamstring eccentric:Quadricep concentric) which consequently confirms that it is a more valid indicator for imbalanced reciprocal parameters and can be used in rehabilitation and sports medicine.

  9. Reliability of isometric knee extension muscle strength measurements made by a hand-held dynamometer and a belt: a comparison of two types of device.

    PubMed

    Katoh, Munenori

    2015-03-01

    [Purpose] The purpose of the present study was to compare the reliability of 2 hand-held dynamometers (HHD-1, 2) with different designs, by performing isometric knee muscle extension measurements two times each. [Subjects] The subjects were 40 young healthy adults. [Methods] The reliability of the measurements was examined using Bland-Altman analysis. [Results] Bland-Altman analysis found a fixed bias in measurements made by HHD-1 with an average limits of agreement (LOA) value of -2.1 kgf. For HHD-2, only random errors were detected, and the minimal detectable change (MDC) was 11.4 kgf. Fixed biases were observed between the two devices with an average LOA value of 2.2 kgf. When the bodyweight ratio was used, fixed biases were observed in measurements made by both devices, and the average value of LOA was -0.03 kgf/kg. The comparison of the two devices revealed only random errors, and MDC was 0.22 kgf/kg. [Conclusion] For HHD measurements using these two devices, the appropriate number of measurements is two times, and comparison of measurement values between the two devices should be avoided.

  10. Reliability of Isometric Knee Extension Muscle Strength Measurements of Healthy Elderly Subjects Made with a Hand-held Dynamometer and a Belt.

    PubMed

    Katoh, Munenori; Isozaki, Koji

    2014-12-01

    [Purpose] The purpose of this study was to examine the reliability of three isometric knee extension strength measurements (IKE) made with a hand-held dynamometer (HHD) and a belt of healthy elderly living in the community as subjects. [Subjects] The subject cohort consisted of 186 healthy elderly people, aged 65 to 79 years, living in local communities. [Methods] IKE of the leg subjects used to kick a ball was measured. IKE of each subject was measured three times using an HHD-belt at intervals of 30 seconds. The reliability of the larger of the first two measurements (LV2) as well as the third measurement (3V) was investigated. [Results] The intraclass correlation coefficients [ICC (1, 1)] for LV2 and 3V were 0.955. Bland-Altman analysis showed a fixed bias, and the limits of agreement ranged from -5.6 to 4.6. [Conclusion] The ICC results show that the test-retest reproducibility of IKE measurements of healthy elderly subjects using an HHD-belt is high. However, Bland-Altman analysis showed a fixed bias, suggesting the need for three measurements.

  11. Resistance Exercise with concurrent whole body vibration preserves isometric knee extension strength during 8 weeks of horizontal bed rest

    NASA Astrophysics Data System (ADS)

    Mulder, E. R.; Stegeman, D. F.; Gerrits, K.; Rittweger, J.; Felsenberg, D.; de Haan, A.

    2005-08-01

    Changes in the quadriceps femoris (QF) muscle with respect to anatomical cross sectional area (CSA), neural activation level and isometric maximal voluntary torque (MVT) were determined in 18 healthy men subjected to 8 weeks of horizontal bed rest (BR) with (n = 9) and without (Ctrl; n = 9) 6 days/week resistance exercise concurrent with whole body vibration (RVE). For Ctrl, mean QF CSA decreased linearly over time to a reduction of 14.3 ± 4.9% at the end of BR. For RVE, exercise during BR significantly mitigated this reduction (3.9 ± 4.4%). Prior to and seven times during BR, MVT values were obtained together with neural activation levels, the latter by means of a superimposed stimulation technique. MVT was maintained for RVE during BR, whereas for Ctrl, MVT was significantly reduced by 14.2 ± 8.1% after 8 weeks. In contrast to previous reports, the maximal voluntary activation remained unaltered for both groups throughout the study. For Ctrl, the absence of a change in neural activation might be related to the repeated testing during the bed rest, which had presumably resulted in a habituation to the task. When both groups were pooled, a significant positive correlation (R= 0.62; P < 0.01) was observed between changes in CSA and changes in MVT.

  12. Knee extension torque variability after exercise in ACL reconstructed knees.

    PubMed

    Goetschius, John; Kuenze, Christopher M; Hart, Joseph M

    2015-08-01

    The purpose of this study was to compare knee extension torque variability in patients with ACL reconstructed knees before and after exercise. Thirty two patients with an ACL reconstructed knee (ACL-R group) and 32 healthy controls (control group) completed measures of maximal isometric knee extension torque (90° flexion) at baseline and following a 30-min exercise protocol (post-exercise). Exercise included 30-min of repeated cycles of inclined treadmill walking and hopping tasks. Dependent variables were the coefficient of variation (CV) and raw-change in CV (ΔCV): CV = (torque standard deviation/torque mean x 100), ΔCV = (post-exercise - baseline). There was a group-by-time interaction (p = 0.03) on CV. The ACL-R group demonstrated greater CV than the control group at baseline (ACL-R = 1.07 ± 0.55, control = 0.79 ± 0.42, p = 0.03) and post-exercise (ACL-R = 1.60 ± 0.91, control = 0.94 ± 0.41, p = 0.001). ΔCV was greater (p = 0.03) in the ACL-R group (0.52 ± 0.82) than control group (0.15 ± 0.46). CV significantly increased from baseline to post-exercise (p = 0.001) in the ACL-R group, while the control group did not (p = 0.06). The ACL-R group demonstrated greater knee extension torque variability than the control group. Exercise increased torque variability more in the ACL-R group than control group.

  13. β-alanine supplementation improves isometric endurance of the knee extensor muscles

    PubMed Central

    2012-01-01

    Background We examined the effect of four weeks of β-alanine supplementation on isometric endurance of the knee extensors at 45% maximal voluntary isometric contraction (MVIC). Methods Thirteen males (age 23 ± 6 y; height 1.80 ± 0.05 m; body mass 81.0 ± 10.5 kg), matched for pre-supplementation isometric endurance, were allocated to either a placebo (n = 6) or β-alanine (n = 7; 6.4 g·d-1 over 4 weeks) supplementation group. Participants completed an isometric knee extension test (IKET) to fatigue, at an intensity of 45% MVIC, before and after supplementation. In addition, two habituation tests were completed in the week prior to the pre-supplementation test and a further practice test was completed in the week prior to the post-supplementation test. MVIC force, IKET hold-time, and impulse generated were recorded. Results IKET hold-time increased by 9.7 ± 9.4 s (13.2%) and impulse by 3.7 ± 1.3 kN·s-1 (13.9%) following β-alanine supplementation. These changes were significantly greater than those in the placebo group (IKET: t(11) = 2.9, p ≤0.05; impulse: t(11) = 3.1, p ≤ 0.05). There were no significant changes in MVIC force in either group. Conclusion Four weeks of β-alanine supplementation at 6.4 g·d-1 improved endurance capacity of the knee extensors at 45% MVIC, which most likely results from improved pH regulation within the muscle cell as a result of elevated muscle carnosine levels. PMID:22697405

  14. Kinesio Taping effects on knee extension force among soccer players

    PubMed Central

    Serra, Maysa V. G. B.; Vieira, Edgar R.; Brunt, Denis; Goethel, Márcio F.; Gonçalves, Mauro; Quemelo, Paulo R. V.

    2015-01-01

    Background: Kinesio Taping (KT) is widely used, however the effects of KT on muscle activation and force are contradictory. Objective: To evaluate the effects of KT on knee extension force in soccer players. Method: This is a clinical trial study design. Thirty-four subjects performed two maximal isometric voluntary contractions of the lower limbs pre, immediately post, and 24 hours after tape application on the lower limbs. Both lower limbs were taped, using K-Tape and 3M Micropore tape randomly on the right and left thighs of the participants. Isometric knee extension force was measured for dominant side using a strain gauge. The following variables were assessed: peak force, time to peak force, rate of force development until peak force, time to peak rate of force development, and 200 ms pulse. Results: There were no statistically significant differences in the variables assessed between KT and Micropore conditions (F=0.645, p=0.666) or among testing sessions (pre, post, and 24h after) (F=0.528, p=0.868), and there was no statistical significance (F=0.271, p=0.986) for interaction between tape conditions and testing session. Conclusion: KT did not affect the force-related measures assessed immediately and 24 hours after the KT application compared with Micropore application, during maximal isometric voluntary knee extension. PMID:25789557

  15. Twitch potentiation induced by stimulated and voluntary isometric contractions at various torque levels in human knee extensor muscles.

    PubMed

    Miyamoto, Naokazu; Yanai, Toshimasa; Kawakami, Yasuo

    2011-03-01

    The purpose of this study was to compare the extent of twitch potentiation (TP) after stimulated or voluntary contractions at identical intensities for the human knee extensor muscles. Isometric knee extensions of 10 s were performed at 20%, 40%, and 60% of maximal voluntary contraction (MVC) torque level, through percutaneous electrical stimulation of the quadriceps at 80 Hz or voluntary contraction. Twitch responses were evoked by stimulating the femoral nerve percutaneously with supramaximal intensity. The extent of TP after the stimulated contraction was greater than that after the voluntary contraction at the 20% MVC torque level, whereas a stimulated contraction induced a smaller extent of TP than did a voluntary contraction at contraction intensities higher than 40% MVC. We suggest that this contraction intensity dependence of differences in TP after stimulated and voluntary isometric conditioning contractions is responsible for differences in the recruitment pattern of motor units during the conditioning contractions.

  16. Effect of antagonist muscle fatigue on knee extension torque.

    PubMed

    Beltman, J G M; Sargeant, A J; Ball, D; Maganaris, C N; de Haan, A

    2003-09-01

    The effect of hamstring fatigue on knee extension torque was examined at different knee angles for seven male subjects. Before and after a dynamic flexion fatigue protocol (180 degrees s(-1), until dynamic torque had declined by 50%), maximal voluntary contraction extension torque was measured at four knee flexion angles (90 degrees, 70 degrees, 50 degrees and 30 degrees ). Maximal torque generating capacity and voluntary activation of the quadriceps muscle were determined using electrical stimulation. Average rectified EMG of the biceps femoris was determined. Mean dynamic flexion torque declined by 48+/-11%. Extensor maximal voluntary contraction torque, maximal torque generating capacity, voluntary activation and average rectified EMG at the four knee angles were unaffected by the hamstring fatigue protocol. Only at 50 degrees knee angle was voluntary activation significantly lower (15.7%) after fatigue ( P<0.05). In addition, average rectified EMG before fatigue was not significantly influenced by knee angle. It was concluded that a fatigued hamstring muscle did not increase the maximal voluntary contraction extension torque and knee angle did not change coactivation. Three possible mechanisms may explain the results: a potential difference in recruited fibre populations in antagonist activity compared with the fibres which were fatigued in the protocol, a smaller loss in isometric torque generating capacity of the hamstring muscle than was expected from the dynamic measurements and/or a reduction in voluntary activation.

  17. Isometric and isokinetic torque curves at the knee joint.

    PubMed

    Yoon, T S; Park, D S; Kang, S W; Chun, S I; Shin, J S

    1991-03-01

    Isometric and isokinetic torques of bilateral quadriceps and hamstrings were measured with Isokinetic Rehabilitation and Testing System (Model No. Cybex 340) on 40 normal untrained subjects, 20 males and 20 females, ranging between the ages of 23 and 35 years. The mean peak isometric and isokinetic torque values of both muscle groups showed no significant differences between dominant (right) and nondominant (left) limbs in both sexes; however there were significant differences between the male and the female. As the angular velocity increased, the peak torque significantly decreased, and the point of peak torque output occurred significantly later in the range of motion for quadriceps and hamstrings (p less than 0.01). There were no significant changes in the hamstrings to quadriceps (H/Q) ratios as the angular velocity increased. However, there were significant differences of mean H/Q ratio between male and female (p less than 0.01). Height had significant positive correlation with peak isometric and isokinetic torques for both quadriceps and hamstrings (p less than 0.01). Weight was found to correlate significantly with peak isometric and isokinetic torques (p less than 0.01). The mean isometric torques were significantly higher than the mean isokinetic torques for any joint angles in both sexes (p less than .01).

  18. Knee extension strength in obese and nonobese male adolescents.

    PubMed

    Abdelmoula, Achref; Martin, Vincent; Bouchant, Antoine; Walrand, Stéphane; Lavet, Cédric; Taillardat, Michel; Maffiuletti, Nicola A; Boisseau, Nathalie; Duché, Pascale; Ratel, Sébastien

    2012-04-01

    The aim of the present study was to compare "absolute" and "relative" knee extension strength between obese and nonobese adolescents. Ten nonobese and 12 severely obese adolescent boys of similar chronological age, maturity status, and height were compared. Total body and regional soft tissue composition were determined using dual-energy X-ray absorptiometry (DXA). Knee extensors maximum voluntary contraction (MVC) torque was measured using an isometric dynamometer at a knee angle of 60° (0° is full extension). Absolute MVC torque was significantly higher in obese adolescents than in controls. However, although MVC torque expressed per unit of body mass was found to be significantly lower in obese adolescent boys, no significant difference in MVC torque was found between groups when normalized to fat-free mass. Conversely, when correcting for thigh lean mass and estimated thigh muscle mass, MVC torque was significantly higher in the obese group (17.9% and 22.2%, respectively; P <0.05). To conclude, our sample of obese adolescent boys had higher absolute and relative knee extension strength than our nonobese controls. However, further studies are required to ascertain whether or not relative strength, measured with more accurate in vivo methods such as magnetic resonance imaging, is higher in obese adolescents than in nonobese controls.

  19. Assessment of isometricity before and after total knee arthroplasty: a cadaver study.

    PubMed

    Kuster, Markus S; Jeffcote, Benjamin O; Schirm, Andreas C; Jacob, Hilaire; Nicholls, Rochelle L

    2009-10-01

    Total knee arthroplasty (TKA) relies on soft tissue to regulate joint stability after surgery. In practice, the exact balance of the gaps can be difficult to measure, and various methods including intra-operative spreaders or distraction devices have been proposed. While individual ligament strain patterns have been measured, no data exist on the isometricity of the soft tissue envelope as a whole. In this study, a novel device was developed and validated to compare isometricity in the entire soft tissue envelope for both the intact and TKA knee. A spring-loaded rod was inserted in six cadaver knee joints between the tibial shaft and the tibial plateau or tibial tray after removing a 7 mm slice of bone. The displacement of the rod during passive flexion represented variation in tissue tension around the joint. The rod position in the intact knee remained within 1 mm of its initial position between 15 degrees and 135 degrees of flexion, and within 2 mm (+/-1.2 mm) throughout the entire range of motion (0-150 degrees). After insertion of a mobile-bearing TKA, the rod was displaced a mean of 6 mm at 150 degrees (p<0.001). The results were validated using a force transducer implanted in the tibial baseplate of the TKA, which showed increased tibiofemoral force in the parts of the flexion range where the rod was most displaced. The force measurements were highly correlated with the displacement pattern of the spring-loaded rod (r=-0.338; p=0.006). A simple device has been validated to measure isometricity in the soft tissue envelope around the knee joint. Isometricity measurements may be used in the future to improve implantation techniques during TKA surgery.

  20. Muscle Damage following Maximal Eccentric Knee Extensions in Males and Females

    PubMed Central

    2016-01-01

    Aim To investigate whether there is a sex difference in exercise induced muscle damage. Materials and Method Vastus Lateralis and patella tendon properties were measured in males and females using ultrasonography. During maximal voluntary eccentric knee extensions (12 reps x 6 sets), Vastus Lateralis fascicle lengthening and maximal voluntary eccentric knee extensions torque were recorded every 10° of knee joint angle (20–90°). Isometric torque, Creatine Kinase and muscle soreness were measured pre, post, 48, 96 and 168 hours post damage as markers of exercise induced muscle damage. Results Patella tendon stiffness and Vastus Lateralis fascicle lengthening were significantly higher in males compared to females (p<0.05). There was no sex difference in isometric torque loss and muscle soreness post exercise induced muscle damage (p>0.05). Creatine Kinase levels post exercise induced muscle damage were higher in males compared to females (p<0.05), and remained higher when maximal voluntary eccentric knee extension torque, relative to estimated quadriceps anatomical cross sectional area, was taken as a covariate (p<0.05). Conclusion Based on isometric torque loss, there is no sex difference in exercise induced muscle damage. The higher Creatine Kinase in males could not be explained by differences in maximal voluntary eccentric knee extension torque, Vastus Lateralis fascicle lengthening and patella tendon stiffness. Further research is required to understand the significant sex differences in Creatine Kinase levels following exercise induced muscle damage. PMID:26986066

  1. The effects of imagery training on fast isometric knee extensor torque development.

    PubMed

    de Ruiter, Cornelis J; Hutter, Vana; Icke, Chris; Groen, Bart; Gemmink, Anne; Smilde, Hiltsje; de Haan, Arnold

    2012-01-01

    We hypothesized that imagery training would improve the fast onset of neuromuscular activation and thereby fast knee extensor isometric torque development. Forty young healthy participants, not involved in strength training, were assigned to one of four groups: physical training, imagery training, placebo training or control. The three training groups had three 15 min sessions per week for 4 weeks, with a 90 ° knee angle but were tested also at 120 °. At 90 ° knee angle, maximal torque increased (-8%) similarly in all three training groups. The torque-time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) increased (P < 0.05) after physical training (by -100%), but only at 90 °. This increase was significantly different from the delta values (change pre to post) in the control and placebo groups, whereas delta values in the imagery group were similar to those in the placebo group. The increases in TTI40 following physical training were related (r (2) = 0.81, P < 0.05) to significant increases of knee extensor rectified surface EMG at torque onset (EMG40). In conclusion, only physical training led to a knee angle specific increase of contractile impulse that was significantly different from placebo and controls and that was related to improved onset of neuromuscular activation.

  2. The Effect of Tibial Rotation on the Contribution of Medial and Lateral Hamstrings During Isometric Knee Flexion

    PubMed Central

    Jónasson, Gunnlaugur; Helgason, Andri; Ingvarsson, Þorsteinn; Kristjánsson, Arnar Már; Briem, Kristín

    2015-01-01

    Background: Selective atrophy of hamstring components may result from muscle strain or graft harvesting for anterior cruciate ligament reconstruction. Assessment and rehabilitation that specifically targets medial (MH) or lateral (LH) hamstring components may improve patient outcomes. The purpose of this study was to evaluate effects of volitional tibial rotation medially (MR) versus laterally (LR) on activation levels of MH versus LH and strength measures during isometric testing of knee flexors. Hypothesis: Muscle activation of MH and LH during knee flexor strength testing will be augmented when coupled with MR and LR of the tibia, respectively, without affecting knee flexor strength measures. Study Design: Cross-sectional laboratory study. Level of Evidence: Level 3. Methods: Surface electrodes were used to record neuromuscular activity from MH and LH of the right lower limb in 40 healthy young men and women during isometric knee flexor strength testing at 40° of knee flexion, where participants maintained concurrent volitional MR or LR of the tibia. Statistical analyses of variance included general linear models for repeated measures. Results: A significant interaction was found for tibial rotation and hamstring component variables (P < 0.01). When isometric knee flexion was coupled with LR, normalized activation levels were similar for MH and LH. When performed with MR, a significant drop in LH activation led to dissimilar activation levels of the 2 components. Significantly greater strength measures were found when isometric knee flexion was performed with concurrent LR of the tibia (P < 0.01). Both sexes demonstrated the same rotation-dependent differences. Conclusion: Coupling tibial rotation with knee flexor activities primarily affects the LH component. Clinical Relevance: Strategies involving volitional tibial rotation may be considered for specific assessment/rehabilitation of the MH or LH component. PMID:26721286

  3. Effects of series elasticity on the human knee extension torque-angle relationship in vivo.

    PubMed

    Kubo, Keitaro; Ohgo, Kazuya; Takeishi, Ryuichi; Yoshinaga, Kazunari; Tsunoda, Naoya; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-12-01

    The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110 degrees). The elongation of the tendon and aponeurosis of the vastus lateralis muscle was directly measured by ultrasonography, while the participants performed ramp isometric knee extensions to the voluntary maximum at 800 of knee angle. There was no significant difference in the torque value between 50 degrees and 100 degrees, although there was variation in the shape of the "torque-angle" relationship. The variability in the torque-angle curve was not affected by the activation level of agonist and antagonist muscles and the moment arm length. The ratio of torque at 1000 compared to that at 50 degrees was significantly (r(2) = 18-23 %) correlated to the maximal elongation and strain (to initial length) of the tendon structures. These results suggest that increased compliance of tendon structures of the knee extensors may contribute to variations in the torque-angle curves of the knee extensors.

  4. No Critical Peripheral Fatigue Threshold during Intermittent Isometric Time to Task Failure Test with the Knee Extensors

    PubMed Central

    Froyd, Christian; Beltrami, Fernando G.; Millet, Guillaume Y.; Noakes, Timothy D.

    2016-01-01

    It has been proposed that group III and IV muscle afferents provide inhibitory feedback from locomotor muscles to the central nervous system, setting an absolute threshold for the development of peripheral fatigue during exercise. The aim of this study was to test the validity of this theory. Thus, we asked whether the level of developed peripheral fatigue would differ when two consecutive exercise trials were completed to task failure. Ten trained sport students performed two exercise trials to task failure on an isometric dynamometer, allowing peripheral fatigue to be assessed 2 s after maximal voluntary contraction (MVC) post task failure. The trials, separated by 8 min, consisted of repeated sets of 10 × 5-s isometric knee extension followed by 5-s rest between contractions. In each set, the first nine contractions were performed at a target force at 60% of the pre-exercise MVC, while the 10th contraction was a MVC. MVC and evoked force responses to supramaximal electrical femoral nerve stimulation on relaxed muscles were assessed during the trials and at task failure. Stimulations at task failure consisted of single stimulus (SS), paired stimuli at 10 Hz (PS10), paired stimuli at 100 Hz (PS100), and 50 stimuli at 100 Hz (tetanus). Time to task failure for the first trial (12.84 ± 5.60 min) was longer (P < 0.001) than for the second (5.74 ± 1.77 min). MVC force was significantly lower at task failure for both trials compared with the pre-exercise values (both P < 0.001), but there were no differences in MVC at task failure in the first and second trials (P = 1.00). However, evoked peak force for SS, PS100, and tetanus were all reduced more at task failure in the second compared to the first trial (P = 0.014 for SS, P < 0.001 for PS100 and tetanus). These results demonstrate that subjects do not terminate exercise at task failure because they have reached a critical threshold in peripheral fatigue. The present data therefore question the existence of a

  5. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  6. Investigation of Cervical Fleksor and Extensor Muscle Activation During Isometric Neck Extension Applied by Therraband

    PubMed Central

    Önal, Sercan; Can, Filiz; Yakut, Yavuz; Baltacı, Gül

    2014-01-01

    Objectives: Therrabands are commonly used for resistive exercises, streching and stabilization exercises and also isometric exercises. However, principles of practice of therrabands are mostly focused on exercise variety. Likewise it is only given point to exercise variety during therrabands’ usage at cervical region. Nevertheless, for effective usage of therrabands and for proper assessment of effectiveness response, it is necessary to know the amount of resistance being given or muscle activation response against the resistance given. The aim of this study was to compare activations of cervical flexor and extensor muscles during isometric extension exercise against the resistance of therraband in healthy individuals. Methods: 14 healthy subjects (8 female,6 male)aged between 19-32 have been included in the study. Subjects with neck problems, systemic diseases, history of trauma or operation were excluded. Neck isometric exercises with therraband was 2 sets with 2 minutes’ intervals and EMG records have been taken during exercises. After preparation of the skin, surface electrodes placed on the motor points of sternocleidomastoideus(SCM) and erector spinae(ES) muscles. After taking the average of 3 measures, the first 10 seconds of muscular activations were recorded. The average of integrated EMG(iEMG) values of each records was used for statistical data. Independent T test and Mann Whitney U test were used for the analysis of findings. Results: There was no significant difference between the right ES and left ES’s mean iEMG during isometric neck extension against therraband (p=0.06). Although there was no difference between right SCM and right ES muscles action potentials(t=-0.895; p=0.379), there was a significant difference between left SCM and left ES muscles’ action potentials (z= -2.435; p=0.01). When all the right and left SCM and ES muscle activations were compared, a significant difference was detected in favour of ES muscles ( t= -2.133; p= 0

  7. IS PAIN IN ONE KNEE ASSOCIATED WITH ISOMETRIC MUSCLE STRENGTH IN THE CONTRALATERAL LIMB? - DATA FROM THE OSTEOARTHRITIS INITIATIVE (OAI)

    PubMed Central

    Steidle, E.; Wirth, W.; Glass, N.; Ruhdorfer, A.; Cotofana, S.; Eckstein, F.; Segal, N. A.

    2014-01-01

    Objective Knee pain and muscle weakness confer risk for knee osteoarthritis incidence and progression. The purpose of this study was to determine whether unilateral knee pain influences contralateral thigh muscle strength. Design Of 4796 Osteoarthritis Initiative participants, 224 (mean±SD age 63.9±8.9 years) cases could be matched to a control. Cases were defined as having unilateral knee pain (numerical rating scale (NRS)≥4/10; ≥infrequent pain) and one pain-free knee (NRS 0–1; ≤infrequent pain; WOMAC≤1). Controls were defined as having bilaterally pain-free knees (NRS 0–1; ≤infrequent pain; WOMAC≤1). Maximal isometric muscle strength [N] was compared between limbs in participants with unilateral pain (cases), and between pain-free limbs of cases and controls. Results Knee extensor/flexor strength in pain-free limbs of cases was lower than in bilaterally pain-free controls (−5.5%/–8.4%; p=0.043/p=0.022). Within cases, maximum extensor/flexor strength was significantly lower in the painful than in the pain-free limb (−6.4%/4.1%; p<0.0001/p=0.015). Conclusions These results suggest that strength in limbs without knee pain is associated with the pain status of the contralateral knee. The strength difference between unilateral pain-free cases and matched bilateral pain-free controls was similar to that between limbs in persons with unilateral knee pain. Lower strength due to contralateral knee pain might be centrally mediated. PMID:25768069

  8. Functional imaging of muscle oxygenation and oxygen consumption in the knee extensor muscles during isometric contractions by spatially resolved near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Kek, Khai Jun; Miyakawa, Takahiro; Kudo, Nobuki; Yamamoto, Katsuyuki

    2007-02-01

    In this study, we showed that exercise type- and intensity-dependent regional differences in muscle oxygenation and oxygen consumption rate (Vo II) of the knee extensor muscles could be imaged in real time with a multi-channel spatially resolved near-infrared spectroscopy (SR-NIRS) imaging device. Healthy subjects performed isometric knee extension exercise for 30 s (without- or with-leg-press action) at different exercise intensities [10%, 40% and 70% of maximum voluntary contraction (MVC)]. "Separation-type" probes were attached to the skin over the major knee extensor muscles: vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). Placement of the probes enabled simultaneously measurement of 12 sites over a skin area of about 30 cm2 (temporal resolution = 0.25 s). Local Vo II of each muscle, resting Vo II (Vo II, rest) and recovery Vo II (Vo II, rec ), were determined with arterial occlusion before the start and after the end of contraction, respectively. There was no significant difference between the values of Vo II rest, in the muscles. However, during knee extension exercise without-leg-press action, Vo II rec, value of the RF was significantly greater than the values of the VL and VM at all exercise intensities. In contrast, during exercise with-leg-press action, Vo II rec, values of the RF and VM were greater than those of the VL, especially during exercise at 40% and 70% MVC. In summary, the regional differences in muscle oxygenation and Vo II of the knee extensor muscles, probably due to the differences in relative contributions of muscles to exercise and in muscle architecture, were imaged using SR-NIRS.

  9. Acute Improvement of Vertical Jump Performance After Isometric Squats Depends on Knee Angle and Vertical Jumping Ability.

    PubMed

    Tsoukos, Athanasios; Bogdanis, Gregory C; Terzis, Gerasimos; Veligekas, Panagiotis

    2016-08-01

    Tsoukos, A, Bogdanis, GC, Terzis, G, and Veligekas, P. Acute improvement of vertical jump performance after isometric squats depends on knee angle and vertical jumping ability. J Strength Cond Res 30(8): 2250-2257, 2016-This study examined the acute effects of maximum isometric squats at 2 different knee angles (90 or 140°) on countermovement jump (CMJ) performance in power athletes. Fourteen national-level male track and field power athletes completed 3 main trials (2 experimental and 1 control) in a randomized and counterbalanced order 1 week apart. Countermovement jump performance was evaluated using a force-plate before and 15 seconds, 3, 6, 9, and 12 minutes after 3 sets of 3 seconds maximum isometric contractions with 1-minute rest in between, from a squat position with knee angle set at 90 or 140°. Countermovement jump performance was improved compared with baseline only in the 140° condition by 3.8 ± 1.2% on the 12th minute of recovery (p = 0.027), whereas there was no change in CMJ height in the 90° condition. In the control condition, there was a decrease in CMJ performance over time, reaching -3.6 ± 1.2% (p = 0.049) after 12 minutes of recovery. To determine the possible effects of baseline jump performance on subsequent CMJ performance, subjects were divided into 2 groups ("high jumpers" and "low jumpers"). The baseline CMJ values of "high jumpers" and "low jumpers" differed significantly (CMJ: 45.1 ± 2.2 vs. 37.1 ± 3.9 cm, respectively, p = 0.001). Countermovement jump was increased only in the "high jumpers" group by 5.4 ± 1.4% (p = 0.001) and 7.4 ± 1.2% (p = 0.001) at the knee angles of 90 and 140°, respectively. This improvement was larger at the 140° angle (p = 0.049). Knee angle during isometric squats and vertical jumping ability are important determinants of the acute CMJ performance increase observed after a conditioning activity.

  10. Effects of hand and knee positions on muscular activity during trunk extension exercise with the Roman chair.

    PubMed

    Park, Se-yeon; Yoo, Won-gyu

    2014-12-01

    This experimental study was performed to investigate the effects of hand and knee positions on muscular activity during back extension exercises with the Roman chair. Eighteen asymptomatic male amateur athletes performed four prone back extension exercises with two hand positions (crossed-arms and behind-the-head), and two knee positions (extended knee and 90° flexed knee). Surface electromyography (sEMG) was performed to collect data from the lower trapezius (LT), latissimus dorsi (LD), erector spinae in the T12 paraspinal region (ES-T12), erector spinae at the L3 level (ES-L3), gluteus maximus (GM), and biceps femoris (BF). Two-way repeated analysis of variance with two within-subject factors (two hand positions and two knee positions) was used to determine the significance of differences between the exercise conditions, and which hand and knee positions resulted in greater activation with exercise variation. The root mean square sEMG values were normalized using the maximum voluntary isometric contraction (MVIC) and represented as the % of the maximum EMG (%mEMG). There was no significant interaction between knee and hand positions in the %mEMG data. The results showed that the hand position affected the normalized activation of LT; the behind-the-head position resulted in significantly greater muscle activation than the crossed-arms hand position (P<0.05). The activations of the LD, ES-T10, ES-L4, and GM were greater in the 90° flexed-knee position compared to the extended-knee position (P<0.05). Although back extension exercise using the Roman chair has been shown to effectively activate the extensor musculature, our results indicated that changing the knee and hand positions could activate specific muscles differently. To achieve greater activation of trunk extensor muscle during extension exercise with the Roman chair, the flexed-knee position is a useful means of increasing resistance.

  11. Co-contraction Recruitment and Spinal Load During Isometric Trunk Flexion and Extension

    PubMed Central

    Granata, Kevin P.; Lee, Patrick E.; Franklin, Timothy C.

    2006-01-01

    Background. Pushing and pulling tasks account for 20% of occupational low-back injury claims. Primary torso muscle groups recruited during pushing tasks include rectus abdominis and the external obliques. However, analyses suggest that antagonistic co-contraction of the para spinal muscles is necessary to stabilize the spine during flexion exertions. The study quantified co-contraction and spinal load differences during isometric flexion and extension exertions. The goal was to provide insight into the mechanisms requiring greater co-contraction during trunk flexion exertions compared to extension exertions. Methods. Electromyographic (EMG) signals were recorded from the trunk muscles of healthy volunteers during isometric trunk flexion and extension exertions. A biomechanical model was implemented to estimate total muscle force from the measured EMG and trunk moment data. A similar model estimated the muscle forces necessary to achieve equilibrium while minimizing the sum of squared muscle forces. The difference in these forces represented co-contraction. Spinal load attributed to co-contraction was computed. Results. Average co-contraction during flexion exertions was approximately twice the value of co-contraction during extension, i.e. 28% and 13% of total muscle forces respectively. Co-contraction accounted for up to 47% of the total spinal load during flexion exertions. Consequently, spinal compression during the flexion tasks was nearly 50% greater than during extension exertions despite similar levels of trunk moment. Interpretation. Co-contraction must be considered when evaluating spinal load during pushing exertions. Results underscore the need to consider neuromuscular control of spinal stability when evaluating the biomechanical risks. PMID:16154249

  12. Effects of prolonged vibration to vastus intermedius muscle on force steadiness of knee extensor muscles during isometric force-matching task.

    PubMed

    Saito, Akira; Ando, Ryosuke; Akima, Hiroshi

    2016-12-01

    Afferent inputs from Ia fibers in muscle spindles are essential for the control of force and prolonged vibration has been applied to muscle-tendon units to manipulate the synaptic input from Ia afferents onto α-motor neurons. The vastus intermedius (VI) reportedly provides the highest contribution to the low-level knee extension torque among the individual synergists of quadriceps femoris (QF). The purpose of the present study was to examine the effect of prolonged vibration to the VI on force steadiness of the QF. Nine healthy men (25.1±4.3years) performed submaximal force-matching task of isometric knee extension for 15s before and after mechanical vibration to the superficial region of VI for 30min. Target forces were 2.5%, 10%, and 30% of maximal voluntary contraction (MVC), and force steadiness was determined by the coefficient of variation (CV) of force. After the prolonged VI vibration, the CV of force at 2.5%MVC was significantly increased, but CVs at 10% and 30%MVCs were not significantly changed. The present study concluded that application of prolonged vibration to the VI increased force fluctuations of the QF during a very low-level force-matching task.

  13. Isometric fatigue patterns in time and time-frequency domains of triceps surae muscle in different knee positions.

    PubMed

    Pereira, Glauber Ribeiro; de Oliveira, Liliam Fernandes; Nadal, Jurandir

    2011-08-01

    The occurrence of fatigue in triceps surae (TS) muscles during sustained plantar flexion contraction is investigated by means of the RMS electromyogram (EMG) and the instantaneous median frequency (IMF) of the short time Fourier transform (STFT). Six male subjects realized a 40% maximal plantar flexion isometric voluntary contraction until fatigue in two knee positions. Electrodes were positioned on gastrocnemius medialis, gastrocnemius lateralis and soleus muscles. The torque (TO) and EMG signals were synchronized. The RMS and the median of the IMF values were obtained, respectively, for each 250 ms and 1s windows of signal. Each signal was segmented into 10 epochs, from which the mean values of IMF, RMS and TO were obtained and submitted to linear regressions to determine parameter trends. Friedman test with the Dunn's post hoc were used to test for differences among muscles activation for each knee position and among slopes of regression curves, as well as to observe changes in TS RMS values over time. The results indicate different activation strategies with the knee extended (KE) in contrast to knee flexed (KF). With the KE, the gastrocnemii showed typical fatigue behavior with significant (p<0.05) IMF reductions and RMS increases over time, while soleus showed concomitant RMS and IMF increases (p<0.05) suggesting an increased soleus contribution to the torque production. With KF, the gastrocnemii were under activated, increasing the role of soleus. Thus, time-frequency analysis represented an important tool for TS muscular fatigue evaluation, allowing differentiates the role of soleus muscle.

  14. Can a finite set of knee extension in supine position be used for a knee functional examination?

    PubMed

    Marin, F; Sangeux, M; Charleux, F; Ho Ba Tho, M-C; Dürselen, L

    2006-01-01

    The kinematic magnetic resonance imaging technique has been developed to provide a functional examination of the knee. Technical limitations require this examination to be performed in supine position, and the knee motion is represented by an assembly of static positions at different knee angles. However, the main knee function is to support the body weight and perform continuous motion, e.g. parallel squat. Our study quantified the knee kinematics of 20 healthy subjects in different motion conditions (finite and continuous) and in different mechanical conditions (continuous unloaded and continuous loaded). We evaluated the angular and localisation difference of a finite helical axis of the knee motion for parallel squat, continuous knee extension in supine position and the finite set of knee extension in supine position. We found large inter-individual dispersion. The majority of subjects had equivalent knee kinematics between continuous knee extension and the finite set of knee extension in supine position, but not between continuous knee extension in supine position and the parallel squat. Therefore, results from a functional examination of a finite set of knee extensions in supine position do not represent the knee motion in a parallel squat. Our results suggest that functional examination of the knee from magnetic resonance imaging do not necessarily reflect the physiological kinematics of the knee. Further investigation should focus on a new magnetic resonance imaging acquisition protocol that allows image acquisition during weight bearing or includes a special device which reproduces the loaded condition.

  15. The effects of electrical stimulation combined with continuous passive motion versus isometric exercise on symptoms, functional capacity, quality of life and balance in knee osteoarthritis: randomized clinical trial.

    PubMed

    Tok, Fatih; Aydemir, Koray; Peker, Fatma; Safaz, Ismail; Taşkaynatan, Mehmet Ali; Ozgül, Ahmet

    2011-02-01

    The aim of this study was to evaluate effects of electrical stimulation combined with continuous passive motion (CPM-ES) versus isometric exercise on symptoms, functional capacity, quality of life, muscle strength, knee and thigh circle measurements, and balance in knee osteoarthritis (OA). This is a randomized clinical trial. The study was done in Gulhane Military Medical Academy (GMMA) Rehabilitation Center. Forty patients with knee OA were included in this study. Participants were randomly assigned to two groups: 20 patients placed in Group 1 were treated with conventional physical therapy and CPM-ES combination; 20 patients in Group 2 were treated with conventional physical therapy and isometric exercise. Therapies were applied 3 weeks, 5 days per week. The following main outcome measures were done: values of pain (VAS was used), WOMAC, SF-36, knee and thigh circle measurements, isokinetic tests, dynamic and static balance tests were determined at baseline and after the treatment. There were no statistically significant differences in the tested variables between the groups for post-treatment values. Dynamic and static balance test improved statistically strongly significantly in both groups. The findings of this study demonstrate that knee OA patients could improve their balance function in both static and dynamic conditions after CPM-ES combination or isometric exercise therapy. The improvement might prevent knee OA patients from falling down and increase their sense of security during physical activities.

  16. Effects of Series Elasticity on the Human Knee Extension Torque-Angle Relationship in Vivo

    ERIC Educational Resources Information Center

    Kubo, Keitaro; Ohgo, Kazuya; Takeishi, Ryuichi; Yoshinaga, Kazunari; Tsunoda, Naoya; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2006-01-01

    The purpose of this study was to investigate the effects of series elasticity on the torque-angle relationship of the knee extensors in vivo. Forty-two men volunteered to take part in the present study. The participants performed maximal voluntary isometric contractions at eight knee-joint angles (40, 50, 60, 70, 80, 90, 100, 110[degree]). The…

  17. Effect of stretching on agonist-antagonist muscle activity and muscle force output during single and multiple joint isometric contractions.

    PubMed

    McBride, J M; Deane, R; Nimphius, S

    2007-02-01

    Eight moderately active male subjects where tested for peak force in an isometric knee extension test and peak force and rate of force development in an isometric squat test. Both tests where performed at a 100 degrees knee angle and average integrated electromyography (IEMG) was measured from the vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) muscles. Subjects performed the two conditions, stretching (S) or control (C) in a randomized order. Subjects where tested for baseline strength measures in both the isometric knee extension and isometric squat and then either stretched or sat quietly for 10 min. Following S or C subjects where then tested at six time points. Following S peak force in the isometric knee extension was significantly (P < or = 0.05) less than C at 1, 2, 8 and 16 min post. No significant difference in peak force was found between S and C in the isometric squat. However, following S the rate of force development in the isometric squat was significantly less than C at immediately post. No significant differences where observed in IEMG of the VM or VL between S and C in either the isometric knee extension or isometric squat. However, IEMG significantly decreased in the BF at 1 min post after S in comparison with C in both the isometric knee extension and isometric squat. Stretching appears to decrease muscle force output in a single joint isometric contraction and rate of force development in a multiple joint isometric contraction. Possible changes in agonist-antagonist muscle activity patterns need to be further examined.

  18. An Investigation into Reliability of Knee Extension Muscle Strength Measurements, and into the Relationship between Muscle Strength and Means of Independent Mobility in the Ward: Examinations of Patients Who Underwent Femoral Neck Fracture Surgery

    PubMed Central

    Katoh, Munenori; Kaneko, Yoshihiro

    2014-01-01

    [Purpose] The purpose of the present study was to investigate the reliability of isometric knee extension muscle strength measurement of patients who underwent femoral neck fracture surgery, as well as the relationship between independent mobility in the ward and knee muscle strength. [Subjects] The subjects were 75 patients who underwent femoral neck fracture surgery. [Methods] We used a hand-held dynamometer and a belt to measure isometric knee extension muscle strength three times, and used intraclass correlation coefficients (ICCs) to investigate the reliability of the measurements. We used a receiver operating characteristic curve to investigate the cutoff values for independent walking with walking sticks and non-independent mobility. [Results] ICCs (1, 1) were 0.9 or higher. The cutoff value for independent walking with walking sticks was 0.289 kgf/kg on the non-fractured side, 0.193 kgf/kg on the fractured side, and the average of both limbs was 0.238 kgf/kg. [Conclusion] We consider that the test-retest reliability of isometric knee extension muscle strength measurement of patients who have undergone femoral neck fracture surgery is high. We also consider that isometric knee extension muscle strength is useful for investigating means of independent mobility in the ward. PMID:24567667

  19. Drop-Landing Performance and Knee-Extension Strength After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Kuenze, Christopher M.; Foot, Nathaniel; Saliba, Susan A.; Hart, Joseph M.

    2015-01-01

    Context Individuals with a history of anterior cruciate ligament reconstruction (ACLR) are at greater risk of reinjury and developing early-onset osteoarthritis due to persistent abnormal joint loading. Real-time clinical assessment tools may help identify patients experiencing abnormal movement patterns after ACLR. Objective To compare performance on the Landing Error Scoring System (LESS) between participants with ACLR and uninjured control participants and to determine the relationship between LESS score and knee-extension strength in these participants. Design Controlled laboratory study. Setting Research laboratory. Patients or Other Participants Forty-six recreationally active participants, consisting of 22 with ACLR (12 men, 10 women; age = 22.5 ± 5.0 years, height = 172.8 ± 7.2 cm, mass = 74.2 ± 15.6 kg, body mass index = 24.6 ± 4.0) and 24 healthy control participants (12 men, 12 women; age = 21.7 ± 3.6 years, height = 168.0 ± 8.8 cm, mass = 69.2 ± 13.6 kg, body mass index = 24.3 ± 3.2) were enrolled. Main Outcome Measure(s) Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and LESS scores were measured during a single testing session. We compared LESS scores between groups using a Mann-Whitney U test and the relationships between LESS scores and normalized knee-extension MVIC torque using Spearman ρ bivariate correlations. Results The ACLR participants had a greater number of LESS errors (6.0 ± 3.6) than healthy control participants (2.8 ± 2.2; t44 = −3.73, P = .002). In ACLR participants, lower normalized knee-extension MVIC torque in the injured limb (ρ = −0.455, P = .03) was associated with a greater number of landing errors. Conclusions Participants with ACLR displayed more errors while landing. The occurrence of landing errors was negatively correlated with knee-extension strength, suggesting that weaker participants had more landing errors. Persistent quadriceps weakness commonly

  20. The relationship of force output characteristics during a sit-to-stand movement with lower limb muscle mass and knee joint extension in the elderly.

    PubMed

    Yamada, Takayoshi; Demura, Shinichi

    2010-01-01

    This study examined the reliability of ground reaction force (GRF) parameters during sit-to-stand (STS) movements and the relationships between the GRF parameters and lower limb muscle mass and knee extension muscle strength. Fifty elderly females performed an STS movement twice from a chair adjusted to their knee height and the GRF, lower limb muscle mass and isometric knee extension muscle strength were measured. Reliabilities of GRF parameters were high (intra-class correlation coefficient=ICC=0.70-0.95). Parameters on force output during trunk flexion phase (ground reaction force at hip-lift off, sum of force output between beginning of STS movement and hip-lift off) differed significantly between trials, but their effect sizes were small (0.15-0.23). GRF parameters during hip-lift off and knee-hip joint extension phases significantly correlated with knee extension strength (|r|=0.29-0.64) but not lower limb muscle mass. In conclusion, the reliability of GRF during STS movement is good in hip-lift off and knee-hip joint extension phases and these phases relate significantly with lower limb muscle function. These two phases are useful for evaluation of leg muscle function of the elderly.

  1. Comparison of different passive knee extension torque-angle assessments.

    PubMed

    Freitas, Sandro R; Vaz, João R; Bruno, Paula M; Valamatos, Maria J; Mil-Homens, Pedro

    2013-11-01

    Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to which reliability may be affected by the position of the subjects is also unclear. Therefore, we conducted an analysis of the intra- and inter-session reliability of two methods of assessing passive knee extension: (A) a 2D kinematic analysis coupled to a custom-made device that enabled the direct measurement of resistance to stretch and (B) an isokinetic dynamometer used in two testing positions (with the non-tested thigh either flexed at 45° or in the neutral position). The intra-class correlation coefficients (ICCs) of torque, the slope of the torque-angle curve, and the parameters of the mathematical model that were fit to the torque-angle data for the above conditions were measured in sixteen healthy male subjects (age: 21.4 ± 2.1 yr; BMI: 22.6 ± 3.3 kg m(-2); tibial length: 37.4 ± 3.4 cm). The results found were: (1) methods A and B led to distinctly different torque-angle responses; (2) passive torque-angle relationship and stretch tolerance were influenced by the position of the non-tested thigh; and (3) ICCs obtained for torque were higher than for the slope and for the mathematical parameters that were fit to the torque-angle curve. In conclusion, the measurement method that is used and the positioning of subjects can influence the passive knee extension torque-angle outcome.

  2. Isometric knee extensor fatigue following a Wingate test: peripheral and central mechanisms.

    PubMed

    Fernandez-del-Olmo, M; Rodriguez, F A; Marquez, G; Iglesias, X; Marina, M; Benitez, A; Vallejo, L; Acero, R M

    2013-02-01

    Central and peripheral fatigue have been explored during and after running or cycling exercises. However, the fatigue mechanisms associated with a short maximal cycling exercise (30 s Wingate test) have not been investigated. In this study, 10 volunteer subjects performed several isometric voluntary contractions using the leg muscle extensors before and after two bouts of cycling at 25% of maximal power output and two bouts of Wingate tests. Transcranial magnetic stimulation (TMS) and electrical motor nerve stimulation (NM) were applied at rest and during the voluntary contractions. Maximal voluntary contraction (MVC), voluntary activation (VA), twitch amplitude evoked by electrical nerve stimulation, M wave and motor potential evoked by TMS (MEP) were recorded. MVC, VA and twitch amplitude evoked at rest by NM decreased significantly after the first and second Wingate tests, indicating central and peripheral fatigue. MVC and VA, but not the twitch amplitude evoked by NM, recovered before the second Wingate test. These results suggest that the Wingate test results in a decrease in MVC associated with peripheral and central fatigue. While the peripheral fatigue is associated with an intramuscular impairment, the central fatigue seems to be the main reason for the Wingate test-induced impairment of MVC.

  3. Knee Extension Range of Motion at 4 Weeks Is Related to Knee Extension Loss at 12 Weeks After Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Noll, Sarah; Garrison, J. Craig; Bothwell, James; Conway, John E.

    2015-01-01

    Background: The anterior cruciate ligament (ACL) is commonly torn, and surgical reconstruction is often required to allow a patient to return to their prior level of activity. Avoiding range of motion (ROM) loss is a common goal, but little research has been done to identify when ROM loss becomes detrimental to a patient’s future function. Purpose: To determine whether there is a relationship between early knee side-to-side extension difference after ACL reconstruction and knee side-to-side extension difference at 12 weeks. The hypothesis was that early (within the first 8 weeks) knee side-to-side extension difference will be predictive of knee side-to-side extension difference seen at 12 weeks. Study Design: Cohort study; Level of evidence, 3. Methods: Knee side-to-side extension difference measures were taken on 74 patients undergoing ACL reconstruction rehabilitation at the initial visit and 4, 8, and 12 weeks postoperatively. Visual analog scores (VAS) and International Knee Documentation Committee (IKDC) scores were also recorded at these time frames. Results: There was a strong relationship between knee extension ROM at 4 and 12 weeks (r = 0.639, P < .001) and 8 and 12 weeks (r = 0.742, P < .001). When the variables of knee extension ROM at initial visit and 4 and 8 weeks were entered into a regression analysis, the predictor variable explained 61% (R2 = 0.611) of variance for knee extension ROM at 12 weeks, with 4 weeks (R2 = 0.259) explaining the majority of this variance. Conclusion: This study found that a patient’s knee extension at 4 weeks was strongly correlated with knee extension at 12 weeks. Clinical Relevance: This information may be useful for clinicians treating athletic patients who are anxious for return to sport by providing them an initial goal to work toward in hopes of ensuring successful rehabilitation of their knee. PMID:26675061

  4. Influence of obstructive sleep apnea syndrome in the fluctuation of the submaximal isometric torque of knee extensors in patients with early-grade osteoarthritis

    PubMed Central

    Silva, Andressa; Mello, Marco T.; Serrão, Paula R.; Luz, Roberta P.; Bittencourt, Lia R.; Mattiello, Stela M.

    2015-01-01

    OBJECTIVE: The aim of this study was to investigate whether obstructive sleep apnea (OSA) alters the fluctuation of submaximal isometric torque of the knee extensors in patients with early-grade osteoarthritis (OA). METHOD: The study included 60 male volunteers, aged 40 to 70 years, divided into four groups: Group 1 (G1) - Control (n=15): without OA and without OSA; Group 2 (G2) (n=15): with OA and without OSA; Group 3 (G3) (n=15): without OA and with OSA; and Group 4 (G4) (n=15) with OA and with OSA. Five patients underwent maximal isometric contractions of 10 seconds duration each, with the knee at 60° of flexion to determine peak torque at 60°. To evaluate the fluctuation of torque, 5 submaximal isometric contractions (50% of maximum peak torque) of 10 seconds each, which were calculated from the standard deviation of torque and coefficient of variation, were performed. RESULTS: Significant differences were observed between groups for maximum peak torque, while G4 showed a lower value compared with G1 (p=0.005). Additionally, for the average torque exerted, G4 showed a lower value compared to the G1 (p=0.036). However, no differences were found between the groups for the standard deviation (p=0.844) and the coefficient of variation (p=0.143). CONCLUSION: The authors concluded that OSA did not change the parameters of the fluctuation of isometric submaximal torque of knee extensors in patients with early-grade OA. PMID:26443974

  5. Isokinetic strength during knee flexion and extension in elite fencers.

    PubMed

    Poulis, I; Chatzis, S; Christopoulou, K; Tsolakis, Ch

    2009-06-01

    The relation of leg preference and muscular strength in elite fencers was examined. The dominant and nondominant extensor and flexor muscles of 30 elite fencers (M age = 18.2 yr., SD = 2.0 yr.; M height = 173 cm, SD=7.4 cm; M weight = 62.7 kg, SD=8.9 kg), who were members of the Greek national team, and 14 healthy, young, sedentary adults (8 men, 6 women; M age 23.4 yr., SD = 1.9; M height = 169 cm, SD = 10.5 cm; M weight = 66.3 kg, SD = 9.9) were tested for concentric isokinetic contraction at slow (30 to 60 degrees/sec.) and fast (240 degrees/sec.) angular velocities. Significant multivariate differences were found between groups for knee extension, angle of knee extension, knee flexion, and flexor/extensor peak torque ratio. In contrast, no significant difference was found between the dominant and nondominant legs. There was no significant difference in the flexor/extensor peak torque ratio among any of the concentric angular velocities tested. These findings suggest that long-term training in fencing influences the strength characteristics of the lower limbs.

  6. Fatigue reduces the complexity of knee extensor torque fluctuations during maximal and submaximal intermittent isometric contractions in man

    PubMed Central

    Pethick, Jamie; Winter, Samantha L; Burnley, Mark

    2015-01-01

    Neuromuscular fatigue increases the amplitude of fluctuations in torque output during isometric contractions, but the effect of fatigue on the temporal structure, or complexity, of these fluctuations is not known. We hypothesised that fatigue would result in a loss of temporal complexity and a change in fractal scaling of the torque signal during isometric knee extensor exercise. Eleven healthy participants performed a maximal test (5 min of intermittent maximal voluntary contractions, MVCs), and a submaximal test (contractions at a target of 40% MVC performed until task failure), each with a 60% duty factor (6 s contraction, 4 s rest). Torque and surface EMG signals were sampled continuously. Complexity and fractal scaling of torque were quantified by calculating approximate entropy (ApEn), sample entropy (SampEn) and the detrended fluctuation analysis (DFA) scaling exponent α. Fresh submaximal contractions were more complex than maximal contractions (mean ± SEM, submaximal vs. maximal: ApEn 0.65 ± 0.09 vs. 0.15 ± 0.02; SampEn 0.62 ± 0.09 vs. 0.14 ± 0.02; DFA α 1.35 ± 0.04 vs. 1.55 ± 0.03; all P < 0.005). Fatigue reduced the complexity of submaximal contractions (ApEn to 0.24 ± 0.05; SampEn to 0.22 ± 0.04; DFA α to 1.55 ± 0.03; all P < 0.005) and maximal contractions (ApEn to 0.10 ± 0.02; SampEn to 0.10 ± 0.02; DFA α to 1.63 ± 0.02; all P < 0.01). This loss of complexity and shift towards Brownian-like noise suggests that as well as reducing the capacity to produce torque, fatigue reduces the neuromuscular system's adaptability to external perturbations. PMID:25664928

  7. The ability of male and female clinicians to effectively test knee extension strength using manual muscle testing.

    PubMed

    Mulroy, S J; Lassen, K D; Chambers, S H; Perry, J

    1997-10-01

    It has been suggested that the accuracy of manual muscle testing is dependent on examiner strength. Our purpose was to relate male and female clinicians' upper extremity strength to their ability to challenge the quadriceps and detect weakness in patients using manual muscle testing. Quadriceps muscles of seven men and 12 women with postpoliomyelitis were tested manually by a male and female clinician while forces were recorded with a hand-held dynamometer. Patients' maximal isometric knee extension force was recorded with a Lido dynamometer and clinicians' maximal vertical push force was recorded with the hand-held dynamometer. Manual muscle testing forces, patient maximum quadriceps forces, and examiner push forces were compared with repeated measures analysis of variance. Female examiners' maximal vertical push force (235.7 +/- 54.3 N) was not significantly different from either female or male patients' maximal quadriceps force (166.8 +/- 66.7 N and 341.6 +/- 123.7 N) but was only 60% and 40% of the isometric knee extension forces generated by a group of normal women and men. Male examiners were significantly stronger (357.0 +/- 93.4 N) than the female but not the male patients and produced 90% and 60% of the normal isometric quadriceps forces for women and men. Examiners gave appropriate grades in 30 of 38 tests. Examiner strength limits detection of moderate quadriceps weakness with manual resistance. Most of the muscle test grades, however, were appropriate, given the examiner's upper extremity strength. Clinicians using manual muscle testing should determine their maximal vertical push force and the extent of weakness they can detect.

  8. The effectiveness of posterior knee capsulotomies and knee extension osteotomies in crouched gait in children with cerebral palsy.

    PubMed

    Taylor, Daveda; Connor, Justin; Church, Chris; Lennon, Nancy; Henley, John; Niiler, Tim; Miller, Freeman

    2016-11-01

    Crouched gait is common in children with cerebral palsy (CP), and there are various treatment options. This study evaluated the effectiveness of single-event multilevel surgery including posterior knee capsulotomy or distal femoral extension osteotomy to correct knee flexion contracture in children with CP. Gait analyses were carried out to evaluate gait preoperatively and postoperatively. Significant improvements were found in physical examination and kinematic measures, which showed that children with CP and crouched gait who develop knee flexion contractures can be treated effectively using single-event multilevel surgery including a posterior knee capsulotomy or distal femoral extension osteotomy.

  9. Knee extension and flexion: MR delineation of normal and torn anterior cruciate ligaments

    SciTech Connect

    Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru; Anno, Izumi; Itai, Yuji

    1996-03-01

    Our goal was to assess the effect of joint position of semiflexed and extended knees in MR delineation of the anterior cruciate ligament (ACL). With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semiflexed position (average 45{degrees} of flexion) within the magnet bore. Sets of oblique sagittal MR images were obtained for both extended and flexed knee positions. Thirty-two knees with intact ACLs and 43 knees with arthroscopically proven ACL tears were evaluated. Two observers compared paired MR images of both extended and flexed positions and rated them by a relative three point scale. Anatomic correlation in MR images was obtained by a cadaveric knee with incremental flexion. The MR images of flexed knees were more useful than of extended knees in 53% of the case reviews of femoral attachments and 36% of reviews of midportions of normal ACLs. Compared with knee extensions, the MR images for knee flexion provided better clarity in 48% of reviews of disrupted sites and 52% of residual bundles of torn ACLs. Normal ACL appeared taut in the knee extension and lax in semiflexion. Compared with MR images of knees in extension, MR images of knees in flexion more clearly delineate the femoral side of the ligament with wider space under the intercondylar roof and with decreased volume-averaging artifacts, providing superior visualization of normal and torn ACLs. 13 refs., 7 figs., 1 tab.

  10. Perioperative Rehabilitation Using a Knee Extension Device and Arthroscopic Debridement in the Treatment of Arthrofibrosis

    PubMed Central

    Biggs-Kinzer, Angie; Murphy, Brian; Shelbourne, K. Donald; Urch, Scott

    2010-01-01

    Background: Arthrofibrosis is a postoperative complication of intra-articular knee surgery that can be difficult to treat. Evidence suggests that maximizing knee range of motion may improve outcomes in patients with arthrofibrosis who undergo arthroscopic debridement. Hypothesis: Patients who achieve greater knee range of motion will have better subjective scores. Study Design: Retrospective case series analysis. Methods: A review of records was performed for 33 patients with arthrofibrosis who underwent knee arthroscopy and scar resection coupled with perioperative rehabilitation to maximize knee range of motion. Patient demographics and preoperative and postoperative range of motion measurements were extracted from the records. The International Knee Documentation Committee (IKDC) Subjective Knee Form was administered to assess pain, activity, and knee function. Patients performed a preoperative and postoperative rehabilitation program utilizing a knee extension device to maximize knee extension. Results: According to the IKDC range of motion criteria, 27 of 33 patients achieved normal knee extension, and 14 of 33 achieved normal knee flexion at a mean of 8.6 months after surgery. Patients with normal knee motion had a mean IKDC Subjective Knee Form score of 72.6 ± 13.6, which was significantly higher than patients who did not achieve normal motion (P = .04). Overall, mean IKDC Subjective Knee Form scores improved from 45.3 ± 16.7 preoperatively to 67.1 ± 18.0 postoperatively (P < .01) at a mean of 14.7 months after surgery. Conclusions: Perioperative rehabilitation that emphasizes restoration of normal knee range of motion appears to improve outcomes in patients with arthrofibrosis who undergo arthroscopic scar resection. In support of our hypothesis, patients who achieved greater knee range of motion had better subjective knee scores. PMID:23015970

  11. Greater glucose uptake heterogeneity in knee muscles of old compared to young men during isometric contractions detected by [(18)F]-FDG PET/CT.

    PubMed

    Rudroff, Thorsten; Kindred, John H; Benson, John-Michael; Tracy, Brian L; Kalliokoski, Kari K

    2014-01-01

    We used positron emission tomography/computed tomography (PET/CT) and [(18)F]-FDG to test the hypothesis that glucose uptake (GU) heterogeneity in skeletal muscles as a measure of heterogeneity in muscle activity is greater in old than young men when they perform isometric contractions. Six young (26 ± 6 years) and six old (77 ± 6 years) men performed two types of submaximal isometric contractions that required either force or position control. [(18)F]-FDG was injected during the task and PET/CT scans were performed immediately after the task. Within-muscle heterogeneity of knee muscles was determined by calculating the coefficient of variation (CV) of GU in PET image voxels within the muscles of interest. The average GU heterogeneity (mean ± SD) for knee extensors and flexors was greater for the old (35.3 ± 3.3%) than the young (28.6 ± 2.4%) (P = 0.006). Muscle volume of the knee extensors were greater for the young compared to the old men (1016 ± 163 vs. 598 ± 70 cm(3), P = 0.004). In a multiple regression model, knee extensor muscle volume was a predictor (partial r = -0.87; P = 0.001) of GU heterogeneity for old men (R (2) = 0.78; P < 0.001), and MVC force predicted GU heterogeneity for young men (partial r = -0.95, P < 0.001). The findings demonstrate that GU is more spatially variable for old than young men and especially so for old men who exhibit greater muscle atrophy.

  12. Knee-Extension Training with a Single-Joint Hybrid Assistive Limb during the Early Postoperative Period after Total Knee Arthroplasty in a Patient with Osteoarthritis

    PubMed Central

    Sugaya, Hisashi; Kubota, Shigeki; Onishi, Mio; Kanamori, Akihiro; Sankai, Yoshiyuki; Yamazaki, Masashi

    2016-01-01

    The knee range of motion is an important outcome of total knee arthroplasty (TKA). According to previous studies, the knee range of motion temporarily decreases for approximately 1 month after TKA due to postoperative pain and quadriceps dysfunction following surgical invasion into the knee extensor mechanism. We describe our experience with a knee-extension training program based on a single-joint hybrid assistive limb (HAL-SJ, Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after TKA. HAL-SJ is a wearable robot suit that facilitates the voluntary control of knee joint motion. A 76-year-old man underwent HAL-SJ-based knee-extension training, which enabled him to perform knee function training during the acute phase after TKA without causing increased pain. Thus, he regained the ability to fully extend his knee postoperatively. HAL-SJ-based knee-extension training can be used as a novel post-TKA rehabilitation modality. PMID:27774330

  13. EFFECT OF DIFFERENT FOAM ROLLING VOLUMES ON KNEE EXTENSION FATIGUE

    PubMed Central

    Neto, Victor Gonçalves Corrêa

    2016-01-01

    Background Foam rolling (FR) is a common intervention utilized for the purpose of acutely increasing range-of-motion without subsequent decreases in performance. FR is characterized as an active technique which subject performs upon themselves. Thus, it is believed that the accumulated fatigue can influence whether the task can be continued. Purpose To analyze the effect of different foam rolling volumes on fatigue of the knee extensors. Methods Twenty-five recreationally active females (age 27.7 ± 3.56 y, height 168.4 ± 7.1 cm, weight 69.1 ± 10.2 kg) were recruited for the study. The experiment involved three sets of knee extensions with a pre-determined 10 repetition maximum load to concentric failure. Then, subjects performed the control (CONT) and foam rolling (FR) conditions. FR conditions consisted of different anterior thigh rolling volumes (60-, 90-, and 120-seconds) which were performed during the inter-set rest period. After that, the fatigue index was calculated and compared between each experimental condition. Fatigue index indicates how much (%) resistance the subjects experienced, calculated by the equation: (thidset/firstset) x 100. Results Fatigue index was statistically significantly greater (greater fatigue resistance) for CONT compared to FR90 (p = 0.001) and FR120 (p = 0.001). Similarly, higher fatigue resistance was observed for FR60 when compared to FR120 (p = 0.048). There were no significant differences between the other conditions (p > 0.005). Conclusion The finding of foam rolling fatigue index decline (less fatigue resistance) as compared to control conditions may have implications for foam rolling prescription and implementation, in both rehabilitation and athletic populations. For the purposes of maximum repetition performance, foam rolling should not be applied to the agonist muscle group between sets of knee extensions. Moreover, it seems that volumes greater than 90-seconds are detrimental to the

  14. Lifestyle-Related Factors Contributing to Decline in Knee Extension Strength among Elderly Women: A Cross-Sectional and Longitudinal Cohort Study

    PubMed Central

    Kojima, Narumi; Kim, Miji; Saito, Kyoko; Yoshida, Hideyo; Yoshida, Yuko; Hirano, Hirohiko; Obuchi, Shuichi; Shimada, Hiroyuki; Suzuki, Takao; Kim, Hunkyung

    2015-01-01

    This cross-sectional and 4-year longitudinal cohort study aimed to clarify how various lifestyle-related variables affect knee extension strength in elderly Japanese women. The participants were community-dwelling women (n = 575) living in the Itabashi Ward of Tokyo, Japan aged 75–85 years at baseline (in 2008) who returned for a follow-up examination 4 years later (in 2012). Maximum isometric knee extension strength in the dominant leg was measured during comprehensive medical check-ups at baseline and follow-up. Interviews with participants included questions on their history of 11 diseases and lifestyle-related factors such as physical activity as well as dietary, smoking, and drinking habits. Cross-sectional and longitudinal analyses yielded inconsistent results regarding the associations between lifestyle-related factors and knee extension strength. While going out more frequently and regular physical exercise positively affected baseline knee extension strength, they did not affect knee extension strength in the longitudinal analysis. The longitudinal analysis revealed that more frequent intake of soy products or green and yellow vegetables at baseline decreased age-related knee extension strength decline. The inconsistent results from the cross-sectional and longitudinal analyses indicate that conducting both types of analyses is crucial for researching this type of subject. The present study demonstrates that the age-related decline in muscle strength is lower in those who frequently eat soy products or green and yellow vegetables. Thus, recommending higher intake of soy products, and green and yellow vegetables for the elderly might help maintain their muscle health. PMID:26177292

  15. Percutaneous quadriceps tendon pie-crusting release of extension contracture of the knee.

    PubMed

    Liu, H X; Wen, H; Hu, Y Z; Yu, H C; Pan, X Y

    2014-05-01

    To release extension contracture of the knee, the authors used a minimally invasive technique: percutaneous quadriceps tendon pie-crusting release. Percutaneous pie-crusting release was performed using an 18-gauge needle to puncture the stiff fibrous band of the distal and lateral quadriceps tendon under maximum knee flexion. Quadriceps contracture was gradually released by multiple needle punctures. A knee brace was prescribed for one week and knee flexion exercises were performed on the first postoperative day. This technique was performed in seven post-traumatic stiff knees and five stiff total knee arthroplasties. Mean maximum flexion increased from 37° preoperatively to 50° after arthrolysis and 107(o) after pie-crusting. At a mean follow-up of eight months, mean maximum flexion was 103°. There were no major complications. The technique of quadriceps tendon pie-crusting release is a simple, minimally invasive and effective treatment for knee extension contracture.

  16. The Effects of Hamstring Stretching on Leg Rotation during Knee Extension.

    PubMed

    Kimura, Atsushi

    2013-06-01

    [Purpose] This study investigated the effects of hamstring stretching on leg rotation during active knee extension. [Subjects] Subjects were 100 bilateral legs of 50 healthy women without articular disease. [Methods] Hamstring hardness, leg rotation and muscle activities of the knee extensors during active knee extension were measured before and after hamstring stretching. [Results] Hamstring hardness was significantly decreased after hamstring stretching. The leg rotation angle, variation in leg rotation angle, variation in leg external rotation angle, and muscle activities of the vastus lateralis and rectus femoris were significantly increased after hamstring stretching. A moderate positive correlation was found between variation in leg rotation and variation in muscle hardness in hamstring. [Conclusion] Leg rotation during active knee extension was increased by hamstring stretching. Hamstring stretching would be effective as a pretreatment for restoring proper leg rotation when knee extension is conducted as a therapeutic exercise.

  17. [Sincerity of effort: isokinetic evaluation of knee extension].

    PubMed

    Colombo, R; Demaiti, G; Sartorio, F; Orlandini, D; Vercelli, S; Ferriero, G

    2008-01-01

    The aim of this study was to find a reliable method to evaluate the sincerity of the muscular maximal effort performed in a dynamometric isokinetic test of knee flexion-extension. The coefficient of variation of the peak torque (CV) and 3 new indices were analysed: (1) the average coefficient of variation calculated on the complete peak torque curve (CVM); (2) the slope of the regression line in an endurance test (PRR); (3) the correlation coefficient of the peak torques in the same endurance test (CCR). Twenty healthy subjects underwent assessment in two different trials, maximal (MX) and 50% submaximal (SMX), with 20 minutes of rest between trials. Each trial consisted of 4 tests, each of 3 repetitions, at angular speed of 30, 180, 30, and 180 degrees/s, respectively, and 1 test of 15 repetitions at 240 degrees/s. Our findings confirmed the ability of CV to detect a high percentage of sincere efforts: at 30 degrees/s Sensibility (Sns)=100% and Specificity (Spc)=70%; at 180 degrees/s Sns=75%, Spc=95%. The 3 new indices here proposed showed high characteristics of Sns and Spc, generally better than those of CV. CVM showed at 180 degrees/s Sns=90% and Spc=100%, while at 30 degrees/s Sns=90%, Spc=75%. PRR was the best index identifying all the efforts, except one (Sns=100%, Spc=95%). The CCR coefficient showed Sns and Spc values both of 90%.

  18. Quasi-stiffness of the knee joint in flexion and extension during the golf swing.

    PubMed

    Choi, Ahnryul; Sim, Taeyong; Mun, Joung Hwan

    2015-01-01

    Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment-angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment-angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery.

  19. Skeletal muscle oxygen uptake in obese patients: functional evaluation by knee-extension exercise.

    PubMed

    Lazzer, Stefano; Salvadego, Desy; Porcelli, Simone; Rejc, Enrico; Agosti, Fiorenza; Sartorio, Alessandro; Grassi, Bruno

    2013-08-01

    We hypothesized, in a group of obese women (OB), a more significant impairment of aerobic metabolism during knee extension (KE) exercise vs. that described during cycle ergometer exercise, lending support to the role of skeletal muscles in limiting exercise tolerance in OB. Eleven OB (age 29.5 ± 5.5 years, body mass index 43.2 ± 5.4 kg m(-2)) and 10 non-obese controls (CTRL) women were tested. Fat-free mass of a lower-limb (FFMLL) was assessed by a densitometer. Heart rate (HR) and pulmonary O2 uptake (VO2) were determined during incremental exercise tests to voluntary exhaustion carried out on a custom-built KE ergometer and on a cycle ergometer (CE). FFMLL and maximal isometric force of KE muscles were higher in OB vs. CTRL (+42.4 and +46.2 %, respectively). Peak work rate was significantly lower in OB (-18.4 %) vs. CTRL in CE, but not in KE. Expressed in mL min(-1), peak VO2 was not different in OB vs. CTRL in CE and in KE. After it was divided per unit of FFM involved in the exercises, peak VO2 was significantly lower in OB vs. CTRL, both for CE (-19 %) and KE (-33 %). Expressed per unit of exercising muscle mass, peak oxidative function is impaired in OB. The impairment is more pronounced after limitations related to cardiovascular O2 delivery are reduced. In OB muscle hypertrophy and the increased muscle force allow to preserve exercise tolerance during aerobic exercises carried out by relatively small muscle masses.

  20. In vivo knee laxity in flexion and extension: a radiographic study in 30 older healthy subjects.

    PubMed

    Heesterbeek, P J C; Verdonschot, N; Wymenga, A B

    2008-01-01

    In order to determine how "tight" a total knee prosthesis should be implanted, it is important to know the amount of laxity in a healthy knee. The objective of this study was to determine knee laxity in extension and flexion in healthy, non-arthritic knees of subjects similar in age to patients undergoing a total knee arthroplasty and to provide guidelines for the orthopaedic surgeon in his attempt to restore the stability of an osteoarthritic knee to normal. Thirty healthy subjects (15 male, 15 female), mean age 62 (SD 6.4) years, were included in the study. For each subject one, randomly selected, knee was stressed in extension and in 70 degrees flexion (15 Nm). Varus and valgus laxity were measured on radiographs. The passive range of motion and active flexion was assessed. Mean valgus laxity in extension was 2.3 degrees (SD 0.9, range 0.2 degrees -4.1 degrees ). In extension mean varus laxity was 2.8 degrees (SD 1.3, range 0.6 degrees -5.4 degrees ). In flexion, mean valgus laxity was 2.5 degrees (SD 1.5, range 0.0 degrees -6.0 degrees ) and mean varus laxity was 3.1 degrees (SD 2.0, range 0.1 degrees -7.0 degrees ). Varus and valgus knee laxity in extension and in flexion were comparable. This study shows that the normal knee in this age group has an inherent degree of varus-valgus laxity. Whether the results of the present study can be used to optimise the total knee arthroplasty implantation technique requires further investigation.

  1. An in vivo study of the effect of distal femoral resection on passive knee extension.

    PubMed

    Smith, Conrad K; Chen, Justin A; Howell, Stephen M; Hull, Maury L

    2010-10-01

    A previous study showed that 1 mm of distal femoral resection restored knee extension 4.5°. We determined the relationship with a more accurate measurement technique. Twenty-six subjects treated with total knee arthroplasty were studied. Digital photographs of the extended knee with and without 1.5 and 3.0 mm thick augments placed between the femoral component and distal femur were analyzed, and knee extension was measured. One millimeter of distal femoral resection restored 1.8° of extension that is less correction than the previous study reported. Because an attempt to correct a 10° extension deficit by resecting the distal femur could require 5 mm or more of bone removal that moves the joint line too proximal, we recommend exploring other techniques before resecting the femur.

  2. Preliminary analysis of knee stress in Full Extension Landing

    PubMed Central

    Makinejad, Majid Davoodi; Abu Osman, Noor Azuan; Wan Abas, Wan Abu Bakar; Bayat, Mehdi

    2013-01-01

    OBJECTIVE: This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height. METHODS: The impact time and loads were measured via inverse dynamic analysis of free landing without knee flexion from three different heights (25, 50 and 75 cm), using five subjects with an average body mass index of 18.8. Three-dimensional data were developed from computed tomography scans and were reprocessed with modeling software before being imported and analyzed by finite element analysis software. The whole leg was considered to be a fixed middle-hinged structure, while impact loads were applied to the femur in an upward direction. RESULTS: Straight landing exerted an enormous amount of pressure on the knee joint as a result of the body's inability to utilize the lower extremity muscles, thereby maximizing the threat of injury when the load exceeds the height-safety threshold. CONCLUSIONS: The researchers conclude that extended-knee landing results in serious deformation of the meniscus and cartilage and increases the risk of bone-to-bone contact and serious knee injury when the load exceeds the threshold safety height. This risk is considerably greater than the risk of injury associated with walking downhill or flexion landing activities. PMID:24141832

  3. Hand-held dynamometry in patients with haematological malignancies: Measurement error in the clinical assessment of knee extension strength

    PubMed Central

    Knols, Ruud H; Aufdemkampe, Geert; de Bruin, Eling D; Uebelhart, Daniel; Aaronson, Neil K

    2009-01-01

    Background Hand-held dynamometry is a portable and inexpensive method to quantify muscle strength. To determine if muscle strength has changed, an examiner must know what part of the difference between a patient's pre-treatment and post-treatment measurements is attributable to real change, and what part is due to measurement error. This study aimed to determine the relative and absolute reliability of intra and inter-observer strength measurements with a hand-held dynamometer (HHD). Methods Two observers performed maximum voluntary peak torque measurements (MVPT) for isometric knee extension in 24 patients with haematological malignancies. For each patient, the measurements were carried out on the same day. The main outcome measures were the intraclass correlation coefficient (ICC ± 95%CI), the standard error of measurement (SEM), the smallest detectable difference (SDD), the relative values as % of the grand mean of the SEM and SDD, and the limits of agreement for the intra- and inter-observer '3 repetition average' and the 'highest value of 3 MVPT' knee extension strength measures. Results The intra-observer ICCs were 0.94 for the average of 3 MVPT (95%CI: 0.86–0.97) and 0.86 for the highest value of 3 MVPT (95%CI: 0.71–0.94). The ICCs for the inter-observer measurements were 0.89 for the average of 3 MVPT (95%CI: 0.75–0.95) and 0.77 for the highest value of 3 MVPT (95%CI: 0.54–0.90). The SEMs for the intra-observer measurements were 6.22 Nm (3.98% of the grand mean (GM) and 9.83 Nm (5.88% of GM). For the inter-observer measurements, the SEMs were 9.65 Nm (6.65% of GM) and 11.41 Nm (6.73% of GM). The SDDs for the generated parameters varied from 17.23 Nm (11.04% of GM) to 27.26 Nm (17.09% of GM) for intra-observer measurements, and 26.76 Nm (16.77% of GM) to 31.62 Nm (18.66% of GM) for inter-observer measurements, with similar results for the limits of agreement. Conclusion The results indicate that there is acceptable relative reliability for

  4. Bilateral Medial Tibiofemoral Joint Stiffness in Full Extension and 20° of Knee Flexion

    PubMed Central

    Aronson, Patricia A; Rijke, Arie M; Ingersoll, Christopher D

    2008-01-01

    Context: The valgus stress test is used clinically to assess injury to the medial knee structures in 2 positions: full extension and some degree of flexion. The amount of flexion used to “isolate” the medial collateral ligament is not consistent in the literature, but most studies have shown that stiffness of the ligaments was consistent between the limbs. Objective: To determine (1) if the stiffness of the medial knee structures was the same bilaterally, and (2) if the stiffness was different in full extension compared with 20° of knee flexion. Design: Criterion standard, before-after design. Setting: University research laboratory. Patients or Other Participants: Both knees of 45 healthy and active volunteers (26 females, 19 males; age  =  23.2 ± 3.96 years, height  =  170.6 ± 7.75 cm, mass  =  74.2 ± 15.14 kg) were studied. Intervention(s): A valgus force of 60 N was applied to the lateral aspect of both knees in full extension and in 20° of flexion. Main Outcome Measure(s): The slope of the force-strain line of the medial knee during a valgus force was calculated using the LigMaster arthrometer. Results: Slope means in full extension were 16.1 ± 3.3 (right knee) and 15.8 ± 3.1(left knee). Means for 20° of flexion were 12.2 ± 3.1 (right) and 11.7 ± 2.8 (left). Stiffness was greater when the knee was in full extension versus 20° of flexion (t44  =  12.04, P < .001). No difference was noted between the slopes of the 2 knees in extension (t44  =  0.74, P  =  .46) or in flexion (t44  =  1.2, P  =  .27). Conclusions: These findings support the use of the contralateral knee as a control. Further, the valgus stress test should be performed in full extension and in some degree of flexion to assess the different restraining structures of the medial tibiofemoral joint. PMID:18345340

  5. Treatment for flexion contracture of the knee during Ilizarov reconstruction of tibia with passive knee extension splint.

    PubMed

    Kwan, M K; Penafort, R; Saw, A

    2004-12-01

    Joint stiffness is one of the complications of limb procedure. It developes as a result of failure of knee flexors to lengthen in tandem with the bone, especially when there is inadequate physical therapy to provide active and passive mobilization of the affected joint. We are reporting four patients who developed fixed flexion contracture of their knees during bone lengthening procedure for the tibia with Ilizarov external fixator. Three of them were treated for congenital pseudoarthrosis and one was for fibular hemimelia. None of them were able to visit the physiotherapist even on a weekly basis. A splint was constructed from components of Ilizarov external fixator and applied on to the existing frame to passively extend the affected knee. Patients and their family members were taught to perform this exercise regularly and eventually near complete correction were achieved. With this result, we would like to recommend the use of this "Passive Knee Extension Splint" to avoid knee flexion Contracture during limb lengthening procedures with Ilizarov external fixators.

  6. Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

    PubMed

    Miyamoto, N; Hirata, K; Kanehisa, H

    2017-01-01

    The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion.

  7. Multijoint kinetic chain analysis of knee extension during the soccer instep kick.

    PubMed

    Naito, Kozo; Fukui, Yosuke; Maruyama, Takeo

    2010-04-01

    Although previous studies have shown that motion-dependent interactions between adjacent segments play an important role in producing knee extension during the soccer instep kick, detailed knowledge about the mechanisms underlying those interactions is lacking. The present study aimed to develop a 3-D dynamical model for the multijoint kinetic chain of the instep kick in order to quantify the contributions of the causal dynamical factors to the production of maximum angular velocity during knee extension. Nine collegiate soccer players volunteered to participate in the experiment and performed instep kicking movements while 3-D positional data and the ground reaction force were measured. A dynamical model was developed in the form of a linked system containing 8 segments and 18 joint rotations, and the knee extension/flexion motion was decomposed into causal factors related to muscular moment, gyroscopic moment, centrifugal force, Coriolis force, gravity, proximal endpoint linear acceleration, and external force-dependent terms. The rapid knee extension during instep kicking was found to result almost entirely from kicking leg centrifugal force, trunk rotation muscular moment, kicking leg Coriolis force, and trunk rotation gyroscopic-dependent components. Based on the finding that rapid knee extension during instep kicking stems from multiple dynamical factors, it is suggested that the multijoint kinetic chain analysis used in the present study is more useful for achieving a detailed understanding of the cause of rapid kicking leg movement than the previously used 2-D, two-segment kinetic chain model. The present results also indicated that the centrifugal effect due to the kicking hip flexion angular velocity contributed substantially to the generation of a rapid knee extension, suggesting that the adjustment between the kicking hip flexion angular velocity and the leg configuration (knee flexion angle) is more important for effective instep kicking than other

  8. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY: A RANDOMIZED CROSS-OVER STUDY

    PubMed Central

    Wilquin, Lousia; Jakobsen, Thomas Linding; Holsgaard-Larsen, Anders; Bandholm, Thomas

    2017-01-01

    Background Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase agonist muscle activity, especially if the exercise is conducted using rapid muscle contractions. Purpose The purpose of this study was to examine if patients with total knee arthroplasty could perform rapid knee-extensions using a 10 RM load four to eight weeks after surgery, and the degree to which rapid knee-extensions were associated with greater voluntary quadriceps muscle activity during an experimental strength training session, compared to that elicited using slow knee-extensions. Study Design A randomized cross-over study. Methods Twenty-four patients (age 66.5) 4-8 weeks post total knee arthroplasty randomly performed one set of five rapid, and one set of five slow knee-extensions with the operated leg, using a load of their 10 repetition maximum, while surface electromyography recordings were obtained from the vastus medialis and lateralis of the quadriceps muscle. Results Data from 23 of the 24 included patients were analyzed. Muscle activity was significantly higher during rapid knee-extensions (120.2% [10th-90th percentile: 98.3-149.1]) compared to slow knee-extensions (106.0% [88.8-140.8]) for the vastus lateralis (p<0.01), but not for the vastus medialis (120.8% [90.4-134.0]) and (121.8% [93.0-133.0]) (p = 0.17), respectively. Slow and rapid knee-extensions were performed at a median angular velocity of 19.7 degrees/sec (13.7-24.4) and 51.4 degrees/sec (28.9-63.1), respectively Conclusion Four to eight weeks after their total knee arthroplasty, the patients in the present study were able to conduct rapid knee-extensions according to the experimental protocol with an approximately doubled angular velocity compared to slow knee-extensions. This was associated with

  9. Isometric strength and steadiness adaptations of the knee extensor muscles to level and downhill treadmill walking in older adults.

    PubMed

    Gault, Mandy Lucinda; Willems, Mark Elizabeth Theodorus

    2013-04-01

    An ageing related decline in muscle strength and steadiness decreases quality of life and increases the risk for falls. Downhill treadmill walking (DTW) may enhance muscle strength and steadiness in older adults. Eighteen healthy older adults (age: 67 ± 4, body mass: 75 ± 14 kg) completed 12-weeks of level treadmill walking (LTW, 0 %, n = 8) or DTW (-10 %, n = 10) (30 min, 3 days per week) at a self-selected walking speed (re-adjusted in week 4 and 8). Maximal voluntary isometric force (MVIF) and electromyography (EMG) of the m. quadriceps femoris (QF) were measured at baseline, 4, 8 and 12 weeks. Steadiness of submaximal (5, 10 and 20 % MVIF) isometric contractions (i.e. coefficient of variation of the force signal) and EMG of QF were measured at baseline and 12 weeks. Baseline MVIF of LTW (340 ± 112 N) and DTW (368 ± 128 N) increased equally by 14 ± 6 and 5 ± 6 % (p < 0.05). Steadiness at 5 %MVIF improved following 12 weeks of LTW (baseline: 0.04 ± 0.01; 12 weeks: 0.03 ± 0.01) and DTW (baseline: 0.04 ± 0.02; 12 weeks: 0.03 ± 0.01 (p < 0.05). EMG root mean square of m. vastus lateralis during MVIF increased by 38 % following 12 weeks of LTW only (p < 0.05). The potential implications for an exercise modality, such as DTW, with a lower oxygen demand, to improve muscle strength could serve as a rehabilitative countermeasure for older adults.

  10. IMPROVEMENTS IN KNEE EXTENSION STRENGTH ARE ASSOCIATED WITH IMPROVEMENTS IN SELF-REPORTED HIP FUNCTION FOLLOWING ARTHROSCOPY FOR FEMOROACETABULAR IMPINGEMENT SYNDROME

    PubMed Central

    Ellis, Thomas J.; Amesur, Ajit K.; Hewett, Timothy E.; Di Stasi, Stephanie

    2016-01-01

    Background Recovery of strength is critical for return to sport, and is a known predictor of functional outcomes in post-surgical orthopedic populations. Muscle weakness is a known impairment in patients with femoroacetabular impingement syndrome (FAIS) but whether improvements in muscle strength after arthroscopy are associated with improved hip function is unknown. Hypothesis/Purpose To examine the relationships between changes in hip and thigh muscle strength and self-reported function in athletes undergoing arthroscopy for FAIS. Study Design Single cohort descriptive and correlational study Methods Twenty-eight athletes underwent strength testing and completed the Hip Outcome Score Activities of Daily Living (HOS-ADL) and Sports (HOS-S) subscales prior to and six months after surgery. Isokinetic knee extension and flexion strength were measured using a Biodex dynamometer at 60 °/s and 300 °/s. Isometric hip abduction strength was measured using a custom dynamometer. Changes in strength, limb symmetry, and HOS scores were assessed using paired t-tests. Spearman's rank correlations were used to examine relationships between change in involved limb strength and change in HOS scores. Results Subjects were tested an average of 32 days before and 178 days after surgery. HOS-ADL and HOS-S subscales improved by a mean of 19.0 ± 21.1 and 23.8 ± 31.9, respectively, over time (p < 0.001). Hip abduction strength did not increase over time in either limb (p ≥ 0.27). Involved limb knee flexion and extension strength did not increase significantly over time (p-values: 0.10-0.48) with the exception of knee extension at 300 °/s (p = 0.04). Uninvolved limb knee extension strength at both velocities and knee flexion strength at 60 °/s improved significantly over time (p < 0.012). Increases in knee extension strength (60 °/s) of the involved limb were significantly correlated with improvements on the HOS-ADL (r = 0.431; 0 = 0

  11. Greater Hip Extension but Not Hip Abduction Explosive Strength Is Associated With Lesser Hip Adduction and Knee Valgus Motion During a Single-Leg Jump-Cut

    PubMed Central

    Cronin, Baker; Johnson, Samuel T.; Chang, Eunwook; Pollard, Christine D.; Norcross, Marc F.

    2016-01-01

    Background: The relationships between hip abductor and extensor strength and frontal plane hip and knee motions that are associated with anterior cruciate ligament injury risk are equivocal. However, previous research on these relationships has evaluated relatively low-level movement tasks and peak torque rather than a time-critical strength measure such as the rate of torque development (RTD). Hypothesis: Females with greater hip abduction and extension RTD would exhibit lesser frontal plane hip and knee motion during a single-leg jump-cutting task. Study Design: Descriptive laboratory study. Methods: Forty recreationally active females performed maximal isometric contractions and single-leg jump-cuts. From recorded torque data, hip extension and abduction RTD was calculated from torque onset to 200 ms after onset. Three-dimensional motion analysis was used to quantify frontal plane hip and knee kinematics during the movement task. For each RTD measure, jump-cut biomechanics were compared between participants in the highest (high) and lowest (low) RTD tertiles. Results: No differences in frontal plane hip and knee kinematics were identified between high and low hip abduction RTD groups. However, those in the high hip extension RTD group exhibited lower hip adduction (high, 3.8° ± 3.0°; low, 6.5° ± 3.0°; P = .019) and knee valgus (high, –2.5° ± 2.3°; low, –4.4° ± 3.2°; P = .046) displacements during the jump-cut. Conclusion: In movements such as cutting that are performed with the hip in a relatively abducted and flexed position, the ability of the gluteus medius to control hip adduction may be compromised. However, the gluteus maximus, functioning as a hip abductor, may take on a pivotal role in controlling hip adduction and knee valgus motion during these types of tasks. Clinical Relevance: Training with a specific emphasis on increasing explosive strength of the hip extensors may be a means through which to improve frontal plane hip and knee

  12. Voluntary Movement Frequencies in Submaximal One- and Two-Legged Knee Extension Exercise and Pedaling

    PubMed Central

    Stang, Julie; Wiig, Håvard; Hermansen, Marte; Hansen, Ernst Albin

    2016-01-01

    Understanding of behavior and control of human voluntary rhythmic stereotyped leg movements is useful in work to improve performance, function, and rehabilitation of exercising, healthy, and injured humans. The present study aimed at adding to the existing understanding within this field. To pursue the aim, correlations between freely chosen movement frequencies in relatively simple, single-joint, one- and two-legged knee extension exercise were investigated. The same was done for more complex, multiple-joint, one- and two-legged pedaling. These particular activities were chosen because they could be considered related to some extent, as they shared a key aspect of knee extension, and because they at the same time were different. The activities were performed at submaximal intensities, by healthy individuals (n = 16, thereof eight women; 23.4 ± 2.7 years; 1.70 ± 0.11 m; 68.6 ± 11.2 kg). High and fair correlations (R-values of 0.99 and 0.75) occurred between frequencies generated with the dominant leg and the nondominant leg during knee extension exercise and pedaling, respectively. Fair to high correlations (R-values between 0.71 and 0.95) occurred between frequencies performed with each of the two legs in an activity, and the two-legged frequency performed in the same type of activity. In general, the correlations were higher for knee extension exercise than for pedaling. Correlations between knee extension and pedaling frequencies were of modest occurrence. The correlations between movement frequencies generated separately by each of the legs might be interpreted to support the following working hypothesis, which was based on existing literature. It is likely that involved central pattern generators (CPGs) of the two legs share a common frequency generator or that separate frequency generators of each leg are attuned via interneuronal connections. Further, activity type appeared to be relevant. Thus, the apparent common rhythmogenesis for the two legs appeared

  13. Minimization of the knee shear joint load in leg-extension equipment.

    PubMed

    Biscarini, A

    2008-10-01

    We developed an analytical biomechanical model for leg-extension equipment and the associated knee-extension/flexion exercises. The shear component, phi(t), of the tibiofemoral joint load was calculated taking into account all the fundamental elements of the equipment mechanics (resistance pad placement, cam/pulley system geometry, selected weight stack, etc.) and the instantaneous values of the relevant kinematical parameters (knee-flexion angle (theta(f)), angular velocity, and angular acceleration). The optimal distance (a(R))(OPT) between the knee-flexion/extension axis and the resistance pad placement point was derived by minimizing phi(t). (a(R))(OPT) is nearly independent of joint angular velocity and, for appreciably high resistance torques, becomes nearly independent of resistance level and cam/pulley geometry: for theta(f)>40 degrees , phi(t) is minimized by placing the resistance pad distally along the lower leg; for theta(f)knee-extension phase and distally during knee-flexion phase (0.17 mknee angular accelerations and hamstrings co-contractions, not predictable in advance, the value of (a(R))(OPT) obtained neglecting these effects still represents a good compromise for joint protection. This work establishes the rational basis for the design and clinical use of a leg-extension equipment that minimizes phi(t).

  14. Absolute reliability of isokinetic knee flexion and extension measurements adopting a prone position.

    PubMed

    Ayala, F; De Ste Croix, M; Sainz de Baranda, P; Santonja, F

    2013-01-01

    The main purpose of this study was to determine the absolute and relative reliability of isokinetic peak torque (PT), angle of peak torque (APT), average power (PW) and total work (TW) for knee flexion and extension during concentric and eccentric actions measured in a prone position at 60, 180 and 240° s(-1). A total of 50 recreational athletes completed the study. PT, APT, PW and TW for concentric and eccentric knee extension and flexion were recorded at three different angular velocities (60, 180 and 240° s(-1)) on three different occasions with a 72- to 96-h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CV(TE)), percentage change in the mean (ChM) and relative reliability with intraclass correlations (ICC(3,1)). For both the knee extensor and flexor muscle groups, all strength data (except APT during knee flexion movements) demonstrated moderate absolute reliability (ChM < 3%; ICCs > 0·70; and CV(TE) < 20%) independent of the knee movement (flexion and extension), type of muscle action (concentric and eccentric) and angular velocity (60, 180 and 240° s(-1)). Therefore, the current study suggests that the CV(TE) values reported for PT (8-20%), APT (8-18%) (only during knee extension movements), PW (14-20%) and TW (12-28%) may be acceptable to detect the large changes usually observed after rehabilitation programmes, but not acceptable to examine the effect of preventative training programmes in healthy individuals.

  15. Characteristics associated with improved knee extension after strength training for individuals with cerebral palsy and crouch gait.

    PubMed

    Steele, K M; Damiano, D L; Eek, M N; Unger, M; Delp, S L

    2012-01-01

    Muscle weakness may contribute to crouch gait in individuals with cerebral palsy, and some individuals participate in strength training programs to improve crouch gait. Unfortunately, improvements in muscle strength and gait are inconsistent after completing strength training programs. The purpose of this study was to examine changes in knee extensor strength and knee extension angle during walking after strength training in individuals with cerebral palsy who walk in crouch gait and to determine subject characteristics associated with these changes. A literature review was performed of studies published since January 2000 that included strength training, three-dimensional motion analysis, and knee extensor strength measurements for individuals with cerebral palsy. Three studies met these criteria and individual subject data was obtained from the authors for thirty crouch gait subjects. Univariate regression analyses were performed to determine which of ten physical examination and motor performance variables were associated with changes in strength and knee extension during gait. Change in knee extensor strength ranged from a 25% decrease to a 215% increase, and change in minimum knee flexion angle during gait ranged from an improvement of 9° more knee extension to 15° more knee flexion. Individuals without hamstring spasticity had greater improvement in knee extension after strength training. Hamstring spasticity was associated with an undesired increase in knee flexion during walking. Subject-specific factors such as hamstring spasticity may be useful for predicting which subjects will benefit from strength training to improve crouch gait.

  16. Trapezoid supracondylar femoral extension osteotomy for knee flexion contractures in patients with haemophilia.

    PubMed

    Mortazavi, S M J; Heidari, P; Esfandiari, H; Motamedi, M

    2008-01-01

    Flexion deformity of the haemophilic knee is a considerable cause of disability and may need to be managed surgically in severe cases. We have used a trapezoid supracondylar femoral extension osteotomy to correct severe knee flexion deformity. Nine severe haemophilic patients with contractures >30 degrees that were unresponsive to conservative measures underwent 11 trapezoid osteotomies. The angle of deformity was measured using anteroposterior and lateral knee X-ray films at maximum extension. Factor levels of 80-100% were achieved before the operation. A trapezoid osteotomy of the distal femur bone was performed using a lateral approach. The frontal plane angular deformity (if any) was corrected at the same time. The osteotomy site was fixed using an Arbeitsgemeinschaft für Osteo synthesefragen (AO) condylar blade plate. Following surgery, the knee was supported by a plaster splint at 20 degrees of flexion. Physiotherapy was started on third postoperative day and continued three times a week. There was no serious complication. The deformities were corrected in all of the patients and the mean range of motion increased form 68.6 degrees to 98.1 degrees . Bleeding episodes decreased in all four knees which had a bleeding score of 3 before surgery. Using the Orthopaedic Advisory Committee of the World Federation of Haemophilia scores, nine good and two fair results were obtained. All patients regained the ability to walk for both short and long distance without any aid, climb the stairs, bath, and use public transportation. Trapezoid supracondylar femoral extension osteotomy should be considered in the surgical management of severe haemophilic flexion deformity of the knee joint.

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

    PubMed

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

    1991-01-01

    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.

  18. Defining the knee joint flexion-extension axis for purposes of quantitative gait analysis: an evaluation of methods.

    PubMed

    Schache, Anthony G; Baker, Richard; Lamoreux, Larry W

    2006-08-01

    Minimising measurement variability associated with hip axial rotation and avoiding knee joint angle cross-talk are two fundamental objectives of any method used to define the knee joint flexion-extension axis for purposes of quantitative gait analysis. The aim of this experiment was to compare three different methods of defining this axis: the knee alignment device (KAD) method, a method based on the transepicondylar axis (TEA) and an alternative numerical method (Dynamic). The former two methods are common approaches that have been applied clinically in many quantitative gait analysis laboratories; the latter is an optimisation procedure. A cohort of 20 subjects performed three different functional tasks (normal gait; squat; non-weight bearing knee flexion) on repeated occasions. Three-dimensional hip and knee angles were computed using the three alternative methods of defining the knee joint flexion-extension axis. The repeatability of hip axial rotation measurements during normal gait was found to be significantly better for the Dynamic method (p<0.01). Furthermore, both the variance in the knee varus-valgus kinematic profile and the degree of knee joint angle cross-talk were smallest for the Dynamic method across all functional tasks. The Dynamic method therefore provided superior results in comparison to the KAD and TEA-based methods and thus represents an attractive solution for orientating the knee joint flexion-extension axis for purposes of quantitative gait analysis.

  19. Knee extension fatigue attenuates repeated force production of the elbow flexors.

    PubMed

    Halperin, Israel; Aboodarda, Saied J; Behm, David G

    2014-01-01

    Non-local muscle fatigue has been demonstrated with unilateral activities, where fatiguing one limb alters opposite limb forces. Fewer studies have examined if non-local fatigue occurs with unrelated muscles. The purpose of this study was to investigate if knee extensors fatigue alters elbow flexors force and electromyography (EMG) activity. Eighteen males completed a control and fatiguing session (randomised). Blood lactate was initially sampled followed by three maximal voluntary contractions (MVC) with the elbow flexors and two with the knee extensors. Thereafter, subjects either sat (control) or performed five sets of bilateral dynamic knee extensions to exhaustion using a load equal to the dominant limb MVC (1-min rest between sets). Immediately afterwards, subjects were assessed for blood lactate and unilateral knee extensors MVC, and after 1 min performed a single unilateral elbow flexor MVC. Two minutes later, subjects performed 12 unilateral elbow flexor MVCs (5 s contraction/10 s rest) followed by a third blood lactate test. Compared to control, knee extensor force dropped by 35% (p < 0.001; ES = 1.6) and blood lactate increased by 18% (p < 0.001; ES = 2.8). Elbow flexor forces were lower after the fatiguing protocol only during the last five MVCs (p < 0.05; ES = ∼ 0.58; ∼ 5%). No changes occurred between conditions in EMG. Elbow flexor forces significantly decreased after knee extensors fatigue. The effect was revealed during the later stages of the repeated MVCs protocol, demonstrating that non-local fatigue may have a stronger effect on repeated rather than on single attempts of maximal force production.

  20. Influence of angular velocity on vastus lateralis and rectus femoris oxygenation dynamics during knee extension exercises.

    PubMed

    Denis, Romain; Wilkinson, Jennifer; De Vito, Giuseppe

    2011-09-01

    The purpose of this study was to investigate whether changes in angular velocity would alter vastus lateralis (VL) and rectus femoris (RF) oxygenation status during maximal isokinetic knee extension exercises. Eleven recreationally active male participants randomly performed ten maximal knee extensions at 30, 60, 120 and 240° s(-1). Tissue oxygenation index (TOI) and total haemoglobin concentration ([tHb]) were acquired from the VL and RF muscles by means of near-infrared spectroscopy (NIRS). Breath-by-breath pulmonary oxygen consumption (VO(2p)) was recorded throughout the tests. Peak torque and VO(2p) significantly decreased as a function of velocity (P<0·05). Interestingly, RF and VL TOI significantly increased as a function of velocity (P<0·05), whereas [tHb] significantly decreased as a function of velocity (P<0·05). A greater number of muscle fibre recruited at slow velocity, where the torque and VO(2p) were the highest, might explain the lower VL and RF TOI observed herein. Furthermore, the increase in local blood flow (suggested by [tHb] changes) during isokinetic knee extension exercises performed at slow angular velocity might have been induced by a higher intramuscular pressure during the contraction phases as well as a greater microcirculatory vasodilatation during relaxation phases. Implementing slow-velocity isokinetic exercises in rehabilitation or other training programmes could delay the short-term anoxia generated by such exercises and result in muscle metabolism enhancement.

  1. Within- and between-session reliability of the maximal voluntary knee extension torque and activation.

    PubMed

    Park, Jihong; Hopkins, J Ty

    2013-01-01

    A ratio between the torque generated by maximal voluntary isometric contraction (MVIC) and exogenous electrical stimulus, central activation ratio (CAR), has been widely used to assess quadriceps function. To date, no data exist regarding between-session reliability of this measurement. Thirteen neurologically sound volunteers underwent three testing sessions (three trials per session) with 48 hours between-session. Subjects performed MVICs of the quadriceps with the knee locked at 90° flexion and the hip at 85°. Once the MVIC reached a plateau, an electrical stimulation from superimposed burst technique (SIB: 125 V with peak output current 450 mA) was manually delivered and transmitted directly to the quadriceps via stimulating electrodes. CAR was calculated by using the following equation: CAR = MVIC torque/MVIC + SIB torque. Intraclass correlation coefficients (ICC) were calculated within- (ICC((2,1))) and between-session (ICC((2,k))) for MVIC torques and CAR values. Our data show that quadriceps MVIC and CAR are very reliable both within- (ICC((2,1)) = 0.99 for MVIC; 0.94 for CAR) and between-measurement sessions (ICC((2,k)) = 0.92 for MVIC; 0.86 for CAR) in healthy young adults. For clinical research, more data of the patients with pathological conditions are required to ensure reproducibility of calculation of CAR.

  2. Development of estimation system of knee extension strength using image features in ultrasound images of rectus femoris

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroki; Watanabe, Tsuneo; Fukuoka, Daisuke; Terabayashi, Nobuo; Hara, Takeshi; Muramatsu, Chisako; Fujita, Hiroshi

    2016-04-01

    The word "Locomotive syndrome" has been proposed to describe the state of requiring care by musculoskeletal disorders and its high-risk condition. Reduction of the knee extension strength is cited as one of the risk factors, and the accurate measurement of the strength is needed for the evaluation. The measurement of knee extension strength using a dynamometer is one of the most direct and quantitative methods. This study aims to develop a system for measuring the knee extension strength using the ultrasound images of the rectus femoris muscles obtained with non-invasive ultrasonic diagnostic equipment. First, we extract the muscle area from the ultrasound images and determine the image features, such as the thickness of the muscle. We combine these features and physical features, such as the patient's height, and build a regression model of the knee extension strength from training data. We have developed a system for estimating the knee extension strength by applying the regression model to the features obtained from test data. Using the test data of 168 cases, correlation coefficient value between the measured values and estimated values was 0.82. This result suggests that this system can estimate knee extension strength with high accuracy.

  3. Identifying the Functional Flexion-extension Axis of the Knee: An In-Vivo Kinematics Study

    PubMed Central

    Yin, Li; Chen, Kaining; Guo, Lin; Cheng, Liangjun; Wang, Fuyou; Yang, Liu

    2015-01-01

    Purpose This study aimed to calculate the flexion-extension axis (FEA) of the knee through in-vivo knee kinematics data, and then compare it with two major anatomical axes of the femoral condyles: the transepicondylar axis (TEA) defined by connecting the medial sulcus and lateral prominence, and the cylinder axis (CA) defined by connecting the centers of posterior condyles. Methods The knee kinematics data of 20 healthy subjects were acquired under weight-bearing condition using bi-planar x-ray imaging and 3D-2D registration techniques. By tracking the vertical coordinate change of all points on the surface of femur during knee flexion, the FEA was determined as the line connecting the points with the least vertical shift in the medial and lateral condyles respectively. Angular deviation and distance among the TEA, CA and FEA were measured. Results The TEA-FEA angular deviation was significantly larger than that of the CA-FEA in 3D and transverse plane (3.45° vs. 1.98°, p < 0.001; 2.72° vs. 1.19°, p = 0.002), but not in the coronal plane (1.61° vs. 0.83°, p = 0.076). The TEA-FEA distance was significantly greater than that of the CA-FEA in the medial side (6.7 mm vs. 1.9 mm, p < 0.001), but not in the lateral side (3.2 mm vs. 2.0 mm, p = 0.16). Conclusion The CA is closer to the FEA compared with the TEA; it can better serve as an anatomical surrogate for the functional knee axis. PMID:26039711

  4. Does the Q − H index show a stronger relationship than the H:Q ratio in regard to knee pain during daily activities in patients with knee osteoarthritis?

    PubMed Central

    Fujita, Remi; Matsui, Yasumoto; Harada, Atsushi; Takemura, Marie; Kondo, Izumi; Nemoto, Tetsuya; Sakai, Tadahiro; Hiraiwa, Hideki; Ota, Susumu

    2016-01-01

    [Purpose] The purpose of this study was to elucidate the relationship between knee muscle strength and knee pain in activities of daily living, based on consideration of the difference between extension and flexion strength (Q − H) and the hamstring:quadriceps (H:Q) ratio in patients with knee osteoarthritis. [Subjects and Methods] The participants were 78 females with knee osteoarthritis, and a total of 133 knees that had not been treated surgically were the targets of this research. The legs were divided according to dominance. Isometric knee extension and flexion muscle strength and knee pain during activities of daily living were measured. The H:Q ratio (flexion/extension muscle strength) and the difference between extension and flexion strength, (extension muscle strength/weight) minus (flexion muscle strength/weight), that is, Q − H, were calculated. The correlation between these indices and the knee pain score during activities of daily living was investigated. [Results] Greater knee pain during activities of daily living was related to lower knee extension muscle strength and Q − H in both the dominant and nondominant legs. Knee flexion muscle strength and the H:Q ratio were not significantly correlated with knee pain during any activities of daily living. [Conclusion] Knee extension muscle strength and Q − H were found to be significantly correlated with knee pain during activities of daily living, whereas the H:Q ratio was not. PMID:28174444

  5. Effects of vascular occlusion on muscular endurance in dynamic knee extension exercise at different submaximal loads.

    PubMed

    Wernbom, Mathias; Augustsson, Jesper; Thomeé, Roland

    2006-05-01

    Strength training with low load under conditions of vascular occlusion has been proposed as an alternative to heavy-resistance exercise in the rehabilitation setting, when large forces acting upon the musculoskeletal system are unwanted. Little is known, however, about the relative intensity at which occlusion of blood flow significantly reduces dynamic muscular endurance and, hence, when it may increase the training effect. The purpose of this study was to investigate endurance during dynamic knee extension at different loads with and without cuff occlusion. Sixteen subjects (20-45 years of age) with strength-training experience were recruited. At 4 test sessions, the subjects performed unilateral knee extensions to failure with and without a pressure cuff around the thigh at 20, 30, 40, and 50% of their 1 repetition maximum (1RM). The pressure cuff was inflated to 200 mm Hg during exercise with occlusion. Significant differences in the number of repetitions performed were found between occluded and nonoccluded conditions for loads of 20, 30, and 40% of 1RM (p < 0.01) but not for the 50% load (p = 0.465). Thus, the application of a pressure cuff around the thigh appears to reduce dynamic knee extension endurance more at a low load than at a moderate load. These results may have implications regarding when it could be useful to apply a tourniquet in order to increase the rate of fatigue and perhaps also the resulting training effect. However, the short- and long-term safety of training under ischemic conditions needs to be addressed in both healthy and less healthy populations. Furthermore, the high acute pain ratings and the delayed-onset muscle soreness associated with this type of training may limit its potential use to highly motivated individuals.

  6. Isometric embeddings of polyhedra

    NASA Astrophysics Data System (ADS)

    Minemyer, Barry

    An indefinite metric polyhedron is a triple (X, T, g) where X is a topological space, T is a simplicial triangulation of X with edge set E, and g is a function from E to the reals. g assigns to each k-dimensional simplex S a unique quadratic form on Rk, denoted by G(S). An indefinite metric polyhedron is called a Euclidean polyhedron if the form G(S) is positive definite for every simplex S. Rpq denotes R p + q endowed with the inner product of signature (p, q). Our first result is that every compact n-dimensional indefinite metric polyhedron with vertex set V admits a simplicial isometric embedding into Rqq where q = max{d, 2n + 1} and d = max{deg(v) | v is in V}. We can use the compact case to extend to the non-compact case, but only if we assume that d = max{deg(v) | v is in V} is less than infinity. Specifically, every (non-compact) indefinite metric polyhedron admits a simplicial isometric embedding into Rpp where p = 2q(d3 - d2 + d + 1) and q and d are defined as above. Finally we use results of Akopyan and Greene to prove that every n-dimensional indefinite metric polyhedron admits a piecewise linear isometric embedding into Rn2n. In Chapter 2 we prove that every short (1-Lipschitz) map from an n-dimensional Euclidean polyhedron into EN is epsilon close to a pl isometric embedding (for anyepsilon > 0) provided N ≥ 3n. We can relax the dimensionality of the Euclidean space to 2n + 1 if we allow our map to be continuous instead of pl. These results are extensions of a result due to Akopyan. We provide a detailed proof of Akopyan's Theorem, as the only currently available proof is in Russian. The remaining results in this work are applications of our continuous isometric embedding theorem above. This result is used to prove that every Pro-Euclidean space of rank at most n admits an isometric embedding into E2n + 1. The result, as well as a theorem due to Bridson, also allows for an approximate isometric embedding theorem for geodesic metric spaces with

  7. Discrepancy between femoral and capillary blood flow kinetics during knee extension exercise.

    PubMed

    Schlup, S J; Ade, C J; Broxterman, R M; Barstow, T J

    2015-12-01

    Capillary blood flow (QCAP) kinetics have previously been shown to be significantly slower than femoral artery (QFA) kinetics following the onset of dynamic knee extension exercise. If the increase in QCAP does not follow a similar time course to QFA, then a substantial proportion of the available blood flow is not distributed to the working muscle. One possible explanation for this discrepancy is that blood flow also increases to the nonworking lower leg muscles. Therefore, the present study aimed to determine if a reduction in lower limb blood flow, via arterial occlusion below the knee, alters the kinetics of QFA and QCAP during knee extension exercise, and thus provide insight into the potential mechanisms controlling the rapid increase in QFA. Subjects performed a ramp max test to determine the work rate at which gas exchange threshold (GET) occurred. At least four constant work rate trials with and without below-knee occlusion were conducted at work rates eliciting ∼ 80% GET. Pulmonary gas exchange, near-infrared spectroscopy and QFA measurements were taken continuously during each exercise bout. Muscle oxygen uptake (VO2m) and deoxy[hemoglobin+myoglobin] were used to estimate QCAP. There was no significant difference between the uncuffed and cuffed conditions in any response (P>0.05). The mean response times (MRT) of QFA were 18.7 ± 14.2s (uncuffed) and 24.6 ± 14.9s (cuffed). QCAP MRTs were 51.8 ± 23.4s (uncuffed) and 56.7 ± 23.2s (cuffed), which were not significantly different from the time constants (τ) of VO2m (39.7 ± 23.2s (uncuffed) and 46.3 ± 24.1s (cuffed). However, the MRT of QFA was significantly faster (P<0.05) than the MRT of QCAP and τVO2m. τVO2m and MRT QCAP were significantly correlated and estimated QCAP kinetics tracked VO2m following exercise onset. Cuffing below the knee did not significantly change the kinetics of QFA, QCAP or VO2m, although an effect size of 1.02 suggested that a significant effect on QFA may have been hidden

  8. Voluntary breathing increases corticospinal excitability of lower limb muscle during isometric contraction.

    PubMed

    Shirakawa, Kazuki; Yunoki, Takahiro; Afroundeh, Roghayyeh; Lian, Chang-Shun; Matsuura, Ryouta; Ohtsuka, Yoshinori; Yano, Tokuo

    2015-10-01

    The aim of the present study was to determine the effects of voluntary breathing on corticospinal excitability of a leg muscle during isometric contraction. Seven subjects performed 5-s isometric knee extension at the intensity of 10% of maximal voluntary contraction (10% MVC). During the 10% MVC, the subjects were instructed to breath normally (NORM) or to inhale (IN) or exhale (OUT) once as fast as possible. Motor-evoked potentials (MEPs) induced by transcranialmagnetic stimulation in the right vastus lateralis (VL) during the 10% MVC were recorded and compared during the three breathing tasks. MEPs in IN and OUT were significantly higher than that in NORM. Effort sense of breathing was significantly higher in IN and OUT than in NORM. There was a significant positive correlation between MEP and effort sense of breathing. These results suggest that activation of the breathing-associated cortical areas with voluntary breathing is involved in the increase in corticospinal excitability of the VL during isometric contraction.

  9. The Isokinetic and Electromyographic Assessment of Knee Muscles Strength in the Short- and Long-Term Type 2 Diabetes

    PubMed Central

    Askary-Ashtiani, Ahmadreza; Ghanjal, Ali; Motaqi, Monireh; Meftahi, Gholam Hossein; Hatef, Boshra; Niknam, Hoda

    2016-01-01

    Background Type 2 diabetes (T2DM) patients are subject to muscle weakness. Objectives The aim of the study was an assessment of electromyographic (EMG) activity of knee muscles during isometric maximal voluntary contraction in the different disease durations of T2DM. Methods Eighteen patients with less than 10 years and twelve patients with more than 10 years of T2DM were compared with nineteen matched healthy control subjects. EMG of flexor and extensor muscles of knee concurrently with isometric maximal peak torque of knee flexion and extension at 75 degrees of knee flexion were recorded in three groups. Results Isometric maximal peak torque of extension and root mean squared (RMS) of vastus lateralis and medial hamstring in the healthy control was significantly higher than both patient groups. Whenever the maximal isometric peak flexion torque was not significantly different between groups, the mean power frequency (MPF) of flexor muscles especially medial hamstrings were higher in the short-term T2DM than healthy control groups. The two factors, gender and age, had significant effect on maximal peak torque and RMS of knee muscles. Conclusions EMG could show the effect of T2DM, gender and age on knee muscles activity. It seems that the medial hamstring was the most sensitive muscle of knee compartment to show the effect of T2DM and difference of short and long-term T2DM in EMG study. PMID:28144413

  10. Effect of Anterior Tibiofemoral Glides on Knee Extension during Gait in Patients with Decreased Range of Motion after Anterior Cruciate Ligament Reconstruction

    PubMed Central

    Hunt, Michael A.; Di Ciacca, Stephen R.; Jones, Ian C.; Padfield, Beverley

    2010-01-01

    ABSTRACT Purpose: The purpose of this preliminary investigation was to evaluate the effect of anterior tibiofemoral glides on maximal knee extension and selected spatiotemporal characteristics during gait in patients with knee extension deficits after anterior cruciate ligament (ACL) reconstruction. Methods: Twelve patients with knee-extension deficits after recent ACL reconstructions underwent quantitative gait analyses immediately before and after 10 minutes of repeated anterior tibiofemoral glides on the operative limb, and again after a 10-minute seated rest period. Results: Maximum knee extension during stance phase of the operative limb significantly increased immediately after the treatment (mean increase: 2.0°±4.1°, 95% CI: 0.6°–3.3°). Maximum knee extension decreased after the 10-minute rest period (mean decrease: 0.9°±1.8°, 95% CI: −0.1°–1.8°), although the decrease was not statistically significant. Small increases in operative limb step length, stride length, and gait speed were observed after the rest period compared to baseline values only. Conclusions: A single session of anterior tibiofemoral glides increases maximal knee extension during the stance phase of gait in patients with knee-extension deficits. Increases in knee extension are small and short-lived, however, suggesting that continued activity is required to maintain the observed improvements. PMID:21629602

  11. Exercise in children with joint hypermobility syndrome and knee pain: a randomised controlled trial comparing exercise into hypermobile versus neutral knee extension

    PubMed Central

    2013-01-01

    Background Knee pain in children with Joint Hypermobility Syndrome (JHS) is traditionally managed with exercise, however the supporting evidence for this is scarce. No trial has previously examined whether exercising to neutral or into the hypermobile range affects outcomes. This study aimed to (i) determine if a physiotherapist-prescribed exercise programme focused on knee joint strength and control is effective in reducing knee pain in children with JHS compared to no treatment, and (ii) whether the range in which these exercises are performed affects outcomes. Methods A prospective, parallel-group, randomised controlled trial conducted in a tertiary hospital in Sydney, Australia compared an 8 week exercise programme performed into either the full hypermobile range or only to neutral knee extension, following a minimum 2 week baseline period without treatment. Randomisation was computer-generated, with allocation concealed by sequentially numbered opaque sealed envelopes. Knee pain was the primary outcome. Quality of life, thigh muscle strength, and function were also measured at (i) initial assessment, (ii) following the baseline period and (iii) post treatment. Assessors were blinded to the participants’ treatment allocation and participants blinded to the difference in the treatments. Results Children with JHS and knee pain (n=26) aged 7-16 years were randomly assigned to the hypermobile (n=12) or neutral (n=14) treatment group. Significant improvements in child-reported maximal knee pain were found following treatment, regardless of group allocation with a mean 14.5 mm reduction on the visual analogue scale (95% CI 5.2 – 23.8 mm, p=0.003). Significant differences between treatment groups were noted for parent-reported overall psychosocial health (p=0.009), specifically self-esteem (p=0.034), mental health (p=0.001) and behaviour (p=0.019), in favour of exercising into the hypermobile range (n=11) compared to neutral only (n=14). Conversely, parent

  12. Ischemic Preconditioning Enhances Muscle Endurance during Sustained Isometric Exercise.

    PubMed

    Tanaka, D; Suga, T; Tanaka, T; Kido, K; Honjo, T; Fujita, S; Hamaoka, T; Isaka, T

    2016-07-01

    Ischemic preconditioning (IPC) enhances whole-body exercise endurance. However, it is poorly understood whether the beneficial effects originate from systemic (e. g., cardiovascular system) or peripheral (e. g., skeletal muscle) adaptations. The present study examined the effects of IPC on local muscle endurance during fatiguing isometric exercise. 12 male subjects performed sustained isometric unilateral knee-extension exercise at 20% of maximal voluntary contraction until failure. Prior to the exercise, subjects completed IPC or control (CON) treatments. During exercise trial, electromyography activity and near-infrared spectroscopy-derived deoxygenation in skeletal muscle were continuously recorded. Endurance time to task failure was significantly longer in IPC than in CON (mean±SE; 233±9 vs. 198±9 s, P<0.001). Quadriceps electromyography activity was not significantly different between IPC and CON. In contrast, deoxygenation dynamics in the quadriceps vastus lateralis muscle was significantly faster in IPC than in CON (27.1±3.4 vs. 35.0±3.6 s, P<0.01). The present study found that IPC can enhance muscular endurance during fatiguing isometric exercise. Moreover, IPC accelerated muscle deoxygenation dynamics during the exercise. Therefore, we suggest that the origin of beneficial effects of IPC on exercise performance may be the enhanced mitochondrial metabolism in skeletal muscle.

  13. A Maximum Muscle Strength Prediction Formula Using Theoretical Grade 3 Muscle Strength Value in Daniels et al.'s Manual Muscle Test, in Consideration of Age: An Investigation of Hip and Knee Joint Flexion and Extension

    PubMed Central

    Matsumura, Masashi; Ichikawa, Kazuna; Takei, Hitoshi

    2017-01-01

    This study attempted to develop a formula for predicting maximum muscle strength value for young, middle-aged, and elderly adults using theoretical Grade 3 muscle strength value (moment fair: Mf)—the static muscular moment to support a limb segment against gravity—from the manual muscle test by Daniels et al. A total of 130 healthy Japanese individuals divided by age group performed isometric muscle contractions at maximum effort for various movements of hip joint flexion and extension and knee joint flexion and extension, and the accompanying resisting force was measured and maximum muscle strength value (moment max, Mm) was calculated. Body weight and limb segment length (thigh and lower leg length) were measured, and Mf was calculated using anthropometric measures and theoretical calculation. There was a linear correlation between Mf and Mm in each of the four movement types in all groups, excepting knee flexion in elderly. However, the formula for predicting maximum muscle strength was not sufficiently compatible in middle-aged and elderly adults, suggesting that the formula obtained in this study is applicable in young adults only. PMID:28133549

  14. A Maximum Muscle Strength Prediction Formula Using Theoretical Grade 3 Muscle Strength Value in Daniels et al.'s Manual Muscle Test, in Consideration of Age: An Investigation of Hip and Knee Joint Flexion and Extension.

    PubMed

    Usa, Hideyuki; Matsumura, Masashi; Ichikawa, Kazuna; Takei, Hitoshi

    2017-01-01

    This study attempted to develop a formula for predicting maximum muscle strength value for young, middle-aged, and elderly adults using theoretical Grade 3 muscle strength value (moment fair: Mf )-the static muscular moment to support a limb segment against gravity-from the manual muscle test by Daniels et al. A total of 130 healthy Japanese individuals divided by age group performed isometric muscle contractions at maximum effort for various movements of hip joint flexion and extension and knee joint flexion and extension, and the accompanying resisting force was measured and maximum muscle strength value (moment max, Mm ) was calculated. Body weight and limb segment length (thigh and lower leg length) were measured, and Mf was calculated using anthropometric measures and theoretical calculation. There was a linear correlation between Mf and Mm in each of the four movement types in all groups, excepting knee flexion in elderly. However, the formula for predicting maximum muscle strength was not sufficiently compatible in middle-aged and elderly adults, suggesting that the formula obtained in this study is applicable in young adults only.

  15. Test-retest reliability of wavelet - and Fourier based EMG (instantaneous) median frequencies in the evaluation of back and hip muscle fatigue during isometric back extensions.

    PubMed

    Coorevits, Pascal; Danneels, Lieven; Cambier, Dirk; Ramon, Herman; Druyts, Hans; Karlsson, J Stefan; De Moor, Georges; Vanderstraeten, Guy

    2008-10-01

    The present study aimed at assessing the test-retest reliability of wavelet - and Fourier derived (instantaneous) median frequencies of surface electromyographic (EMG) measurements of back and hip muscles during isometric back extensions. Twenty healthy subjects (10 males and 10 females) performed a modified Biering-Sørensen test on two separate days, with a 1-week interval between the two tests. Surface EMG measurements were bilaterally performed from the latissimus dorsi, the thoracic and lumbar parts of the longissimus thoracis, the thoracic and lumbar parts of the iliocostalis lumborum, the multifidus, the gluteus maximus and the biceps femoris. In addition, three-dimensional kinematic data were recorded of the subjects' lumbar vertebrae. The (instantaneous) median frequencies were calculated from the EMG signals using continuous wavelet (IMDF) - and short-time Fourier transforms (MDF). Linear regressions performed on the IMDF and MDF data as a function of time yielded slopes (IMDF(slope) and MDF(slope)) and intercepts (IMDF(init) and MDF(init)) of the regression lines. Test-retest reliability was assessed on the normalized slopes and intercept parameters by means of intraclass correlation coefficients (ICC) and standard errors of measurements expressed as percentages of the mean values (% SEM). The results of IMDF(slope) and MDF(slope) parameters indicated ICCs for back and hip muscles between .443 and .727 for IMDF(slope), values between .273 and .734 for MDF(slope), % SEM between 7.6% and 58.9% for IMDF(slope) and % SEM between 8.2% and 25.3% for MDF(slope), respectively. The ICCs for IMDF(init) and MDF(init) parameters varied between .376 and .907 for IMDF(init) and between .383 and .883 for MDF(init), and % SEM ranged from 2.7% to 6.3% for IMDF(init) and from 2.6% to 4.7% for MDF(init), respectively. These results indicate that both wavelet - and Fourier based (instantaneous) median frequency parameters generally are reliable in the analysis of back and

  16. Acute effects of blood flow restriction on muscle activity and endurance during fatiguing dynamic knee extensions at low load.

    PubMed

    Wernbom, Mathias; Järrebring, Rickard; Andreasson, Mikael A; Augustsson, Jesper

    2009-11-01

    The purpose of this study was to investigate muscle activity and endurance during fatiguing low-intensity dynamic knee extension exercise with and without blood flow restriction. Eleven healthy subjects with strength training experience performed 3 sets of unilateral knee extensions with no relaxation between repetitions to concentric torque failure at 30% of the 1 repetition maximum. One leg was randomized to exercise with cuff occlusion and the other leg to exercise without occlusion. The muscle activity in the quadriceps was recorded with electromyography (EMG). Ratings of perceived exertion (RPE) and acute pain were collected immediately, and delayed onset muscle soreness (DOMS) was rated before and at 24, 48, and 72 hours after exercise. The results demonstrated high EMG levels in both experimental conditions, but there were no significant differences regarding maximal muscle activity, except for a higher EMG in the eccentric phase in set 3 for the nonoccluded condition (p = 0.005). Significantly more repetitions were performed with the nonoccluded leg in every set (p < 0.05). The RPE and acute pain ratings were similar, but DOMS was higher in the nonoccluded leg (p < 0.05). We conclude that blood flow restriction during low-intensity dynamic knee extension decreases the endurance but does not increase the maximum muscle activity compared with training without restriction when both regimes are performed to failure. The high levels of muscle activity suggest that performing low-load dynamic knee extensions in a no-relaxation manner may be a useful method in knee rehabilitation settings when large forces are contraindicated. However, similarly to fatiguing blood flow restricted exercise, this method is associated with ischemic muscle pain, and thus its applications may be limited to highly motivated individuals.

  17. Tissue temperature transients in resting contra-lateral leg muscle tissue during isolated knee extension.

    PubMed

    Kenny, Glen P; Reardon, Frank D; Ducharme, Michel B; Reardon, Mark L; Zaleski, Wytek

    2002-12-01

    This study was designed to evaluate the role of non-active tissue in the retention and dissipation of heat during and following intense isolated muscle activity. Six subjects performed an incremental isotonic test (constant angular velocity, increases in force output) on a KIN-COM isokinetic apparatus to determine their maximal oxygen consumption during single knee extensions (VO2sp). In a subsequent session, a thin wire multi-sensor temperature probe was inserted into the left vastus medialis under ultrasound guidance at a specific internal marker. The deepest temperature sensor (tip, Tmu10) was located approximately 10 mm from the femur and deep femoral artery with 2 additional sensors located at 15 (Tmu25) and 30 (Tmu40) mm from the tip. Implant site was midway between and medial to a line joining the anterior superior iliac spine and base of patella. Esophageal temperature (Tes) temperature was measured as an index of core temperature. Subjects rested in a supine position for 60 min followed by 30 min of seated rest in an ambient condition of 22 degree C. Subjects then performed 15 min of isolated single right knee extensions against a dynamic resistance on a KIN COM corresponding to 60% of VO2sp at 60 degree x sec(-1). Exercise was followed by 60 min of seated rest. Resting Tes was 37 degree C while Tmu10, Tmu25, and Tmu40 were 36.58, 36.55 and 36.45 degree C, respectively. Exercise resulted in a Tes increase of 0.31 C above pre-exercise resting. Tmu of the non-exercising leg increased 0.23, 0.19 and 0.09 degree C for Tmu10, Tmu25, and Tmu40, respectively. While Tes decreased to baseline values within approximately 15 min of end-exercise, Tmu10 reached resting values following approximately 40 min of recovery. These results suggest that during isolated muscle activity, convective heat transfer by the blood to non-active muscle tissue may have a significant role in maintaining resting core temperature.

  18. Biceps femoris and semitendinosus tendon/aponeurosis strain during passive and active (isometric) conditions.

    PubMed

    Kellis, Eleftherios

    2016-02-01

    The purpose of this study was to quantify strain and elongation of the long head of the biceps femoris (BFlh) and the semitendinosus (ST) tendon/aponeurosis. Forty participants performed passive knee extension trials from 90° of knee flexion to full extension (0°) followed by ramp isometric contractions of the knee flexors at 0°, 45° and 90° of knee flexion. Two ultrasound probes were used to visualize the displacement of BFlh and ST tendon/aponeurosis. Three-way analysis of variance designs indicated that: (a) Tendon/aponeurosis (passive) elongation and strain were higher for the BFlh than the ST as the knee was passively extended (p<0.05), (b) contraction at each angular position was accompanied by a smaller BFlh tendon/aponeurosis (active) strain and elongation than the ST at higher levels of effort (p<0.05) and (c) combined (passive and active) strain was significantly higher for the BFlh than ST during ramp contraction at 0° but the opposite was observed for the 45° and 90° flexion angle tests (p<0.05). Passive elongation of tendon/aponeurosis has an important effect on the tendon/aponeurosis behavior of the hamstrings and may contribute to a different loading of muscle fibers and tendinous tissue between BFlh and ST.

  19. Residual force enhancement during multi-joint leg extensions at joint- angle configurations close to natural human motion.

    PubMed

    Paternoster, Florian Kurt; Seiberl, Wolfgang; Hahn, Daniel; Schwirtz, Ansgar

    2016-03-21

    The isometric steady-state forces following lengthening are greater than those produced at the same muscle length and activation level but without prior lengthening. Although residual force enhancement (RFE) has been investigated across a range of conditions, its relevance for daily human movement is still poorly understood. We aimed to study RFE in a setup imitating daily activity, i.e., submaximal activation of the lower extremity's muscles with slightly flexed knee joints comparable to human walking. A motor-driven leg press dynamometer was used for randomly arranged purely isometric and isometric-eccentric-isometric contractions. Thirteen subjects performed multi-joint leg extensions, which were feedback-controlled at 30% of maximum voluntary vastus lateralis activation. Isometric-eccentric-isometric contractions incorporated a stretch from 30° to 50° knee flexion, while isometric contractions were performed at 50° knee flexion. Isometric contractions following stretch and purely isometric reference contractions were performed at 50° knee flexion. Kinematics, forces, and muscular activity were measured using 3D optical motion tracking, force plates, and surface EMG of 9 lower limb muscles of the right leg and joint torques were calculated by inverse dynamics. Variables of standardization (EMG, joint angles) showed no differences between contraction conditions. Eight of 13 subjects showed RFE of up to 24.8±32.5% for external forces and joint torques. Because the remaining 5 non-responders failed to produce enhanced forces during the stretch, we believe that RFE is functionally relevant for muscle function comparable to everyday human motion but only if there is enhanced force during stretch that sufficiently triggers mechanisms underlying RFE.

  20. Slope of the lateral density function of extensive air showers around the knee region as an indicator of shower age

    NASA Astrophysics Data System (ADS)

    Dey, Rajat K.; Dam, Sandip

    2016-11-01

    Analyzing simulated extensive air shower (EAS) events generated with the Monte Carlo code CORSIKA, this paper critically studies the characteristics of lateral distribution of electrons in EAS around the knee energy region of the energy spectrum of primary cosmic rays. The study takes into account the issue of the lateral shower age parameter as an indicator of the stage of development of showers in the atmosphere. The correlation of the lateral shower age parameter with other EAS observables is examined, using simulated data in the context of its possible use in a multi-parameter study of EAS, with a view to obtaining information about the nature of the shower initiating primaries at sea level EAS experiments. It is shown that the observed slope of the lateral density function in the 3-dimensional plot, at least for the KASCADE data, supports the idea of a transition from light to heavy mass composition around the knee.

  1. Validity and reliability of a low-cost digital dynamometer for measuring isometric strength of lower limb.

    PubMed

    Romero-Franco, Natalia; Jiménez-Reyes, Pedro; Montaño-Munuera, Juan A

    2016-11-24

    Lower limb isometric strength is a key parameter to monitor the training process or recognise muscle weakness and injury risk. However, valid and reliable methods to evaluate it often require high-cost tools. The aim of this study was to analyse the concurrent validity and reliability of a low-cost digital dynamometer for measuring isometric strength in lower limb. Eleven physically active and healthy participants performed maximal isometric strength for: flexion and extension of ankle, flexion and extension of knee, flexion, extension, adduction, abduction, internal and external rotation of hip. Data obtained by the digital dynamometer were compared with the isokinetic dynamometer to examine its concurrent validity. Data obtained by the digital dynamometer from 2 different evaluators and 2 different sessions were compared to examine its inter-rater and intra-rater reliability. Intra-class correlation (ICC) for validity was excellent in every movement (ICC > 0.9). Intra and inter-tester reliability was excellent for all the movements assessed (ICC > 0.75). The low-cost digital dynamometer demonstrated strong concurrent validity and excellent intra and inter-tester reliability for assessing isometric strength in the main lower limb movements.

  2. Functional impairment of skeletal muscle oxidative metabolism during knee extension exercise after bed rest

    PubMed Central

    Salvadego, Desy; Lazzer, Stefano; Marzorati, Mauro; Porcelli, Simone; Rejc, Enrico; Šimunič, Bostjan; Pišot, Rado; di Prampero, Pietro Enrico

    2011-01-01

    A functional evaluation of skeletal muscle oxidative metabolism during dynamic knee extension (KE) incremental exercises was carried out following a 35-day bed rest (BR) (Valdoltra 2008 BR campaign). Nine young male volunteers (age: 23.5 ± 2.2 yr; mean ± SD) were evaluated. Pulmonary gas exchange, heart rate and cardiac output (by impedance cardiography), skeletal muscle (vastus lateralis) fractional O2 extraction, and brain (frontal cortex) oxygenation (by near-infrared spectroscopy) were determined during incremental KE. Values at exhaustion were considered “peak”. Peak heart rate (147 ± 18 beats/min before vs. 146 ± 17 beats/min after BR) and peak cardiac output (17.8 ± 3.3 l/min before vs. 16.1 ± 1.8 l/min after BR) were unaffected by BR. As expected, brain oxygenation did not decrease during KE. Peak O2 uptake was lower after vs. before BR, both when expressed as liters per minute (0.99 ± 0.17 vs. 1.26 ± 0.27) and when normalized per unit of quadriceps muscle mass (46.5 ± 6.4 vs. 56.9 ± 11.0 ml·min−1·100 g−1). Skeletal muscle peak fractional O2 extraction, expressed as a percentage of the maximal values obtained during a transient limb ischemia, was lower after (46.3 ± 12.1%) vs. before BR (66.5 ± 11.2%). After elimination, by the adopted exercise protocol, of constraints related to cardiovascular O2 delivery, a decrease in peak O2 uptake and muscle peak capacity of fractional O2 extraction was found after 35 days of BR. These findings suggest a substantial impairment of oxidative function at the muscle level, “downstream” with respect to bulk blood flow to the exercising muscles, that is possibly at the level of blood flow distribution/O2 utilization inside the muscle, peripheral O2 diffusion, and intracellular oxidative metabolism. PMID:21921243

  3. The functional anatomy of the iliotibial band during flexion and extension of the knee: implications for understanding iliotibial band syndrome.

    PubMed

    Fairclough, John; Hayashi, Koji; Toumi, Hechmi; Lyons, Kathleen; Bydder, Graeme; Phillips, Nicola; Best, Thomas M; Benjamin, Mike

    2006-03-01

    Iliotibial band (ITB) syndrome is a common overuse injury in runners and cyclists. It is regarded as a friction syndrome where the ITB rubs against (and 'rolls over') the lateral femoral epicondyle. Here, we re-evaluate the clinical anatomy of the region to challenge the view that the ITB moves antero-posteriorly over the epicondyle. Gross anatomical and microscopical studies were conducted on the distal portion of the ITB in 15 cadavers. This was complemented by magnetic resonance (MR) imaging of six asymptomatic volunteers and studies of two athletes with acute ITB syndrome. In all cadavers, the ITB was anchored to the distal femur by fibrous strands, associated with a layer of richly innervated and vascularized fat. In no cadaver, volunteer or patient was a bursa seen. The MR scans showed that the ITB was compressed against the epicondyle at 30 degrees of knee flexion as a consequence of tibial internal rotation, but moved laterally in extension. MR signal changes in the patients with ITB syndrome were present in the region occupied by fat, deep to the ITB. The ITB is prevented from rolling over the epicondyle by its femoral anchorage and because it is a part of the fascia lata. We suggest that it creates the illusion of movement, because of changing tension in its anterior and posterior fibres during knee flexion. Thus, on anatomical grounds, ITB overuse injuries may be more likely to be associated with fat compression beneath the tract, rather than with repetitive friction as the knee flexes and extends.

  4. The contribution of leg press and knee extension strength and power to physical function in people with knee osteoarthritis: A cross-sectional study.

    PubMed

    Tevald, Michael A; Murray, Amanda M; Luc, Brittney; Lai, Kafai; Sohn, David; Pietrosimone, Brian

    2016-12-01

    The purposes of this study were to 1) determine the additional contributions of leg press and knee extensor power, over and above that of strength, to the performance of physical function tasks in people with knee osteoarthritis, and 2) compare the ability of bilateral leg press to unilateral knee extensor strength and power to predict functional task performance.

  5. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task.

    PubMed

    Laubacher, Marco; Aksöz, Efe A; Binder-Macleod, Stuart; Hunt, Kenneth J

    2016-06-13

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable.

  6. Strain and elongation of the vastus lateralis aponeurosis and tendon in vivo during maximal isometric contraction.

    PubMed

    Stafilidis, Savvas; Karamanidis, Kiros; Morey-Klapsing, Gaspar; Demonte, Gianpiero; Brüggemann, Gert-Peter; Arampatzis, Adamantios

    2005-06-01

    The strain and elongation of the vastus lateralis (VL) tendon, tendon plus aponeurosis, and aponeurosis were examined during maximal voluntary contractions on a Biodex-dynamometer (knee angle 115 degrees , hip angle 140 degrees ) in 12 sprinters. Following a warm-up phase, the subjects were instructed to perform a gradual maximal knee extension and hold it for about 3 s. The kinematics of the leg were recorded using a Vicon 512 system with eight cameras operating at 120 Hz. Ultrasonography images were taken simultaneously from the VL myotendinous junction and the mid lateral part of the VL muscle belly. During the maximal isometric knee extensions, the knee joint rotated (13.6+/-5.9 degrees ), leading to an overestimation of the elongation of the tendinous tissues. After correcting for this, the maximal elongation of the VL tendon examined at the myotendinous junction was lower (P<0.05) than the maximal elongation of the VL tendon plus aponeurosis examined at the muscle belly (15 vs. 27 mm, respectively). The maximal estimated strains of the tendon, tendon plus aponeurosis, and aponeurosis showed no statistical differences (8+/-2%, 8+/-1%, and 7+/-2%, respectively, P>0.05). It is concluded that the strains of the human VL tendon, VL tendon plus aponeurosis, and VL aponeurosis, as estimated in vivo by two dimensional ultrasound during maximal isometric contractions, do not differ from each other. The displacement measured at a cross point in the VL muscle belly is significantly greater than that measured at the VL myotendinous junction.

  7. Leg extension test, sEMG and vibratory stimuli to assess functional recovery following knee joint surgery

    PubMed Central

    Foti, Calogero; Laurini, Alessandro; Tiberti, Simone; Carli, Giancarlo; Tsarpela, Olga; Adamidis, Kostas; Bonifazi, Marco; Giombini, Arrigo; Tihanyi, Joszef; von Duvillard, Serge; De Vita, Marilena; Bosco†, Carmelo

    2012-01-01

    Summary Objective: the purpose of this study was to introduce new procedure to determine the magnitude of functional recovery after knee surgery. Design: we compared the performance in the leg extension test and the response in the sEMG activity to vibration in the operated to the non-operated leg. Thirty-eight patients with knee operation and 14 healthy subjects participated in these experiments. Results: during leg extension test, the mechanical power of the operated leg showed a lower value (P<0.001) than the contralateral one, while no differences were noted in the sEMG activity. The sEMG activity during vibration treatment was higher in the operated compared to non-operated leg (P<0.001). It has been suggested that the reduced motility trigger functional adaptations that are exhibited via the vibration test. Conclusions: results of our study suggest that combination of vibration and sEMG recordings may detect the impairment as well as monitoring progress of the rehabilitation programs. PMID:23738286

  8. Effects of Proprioceptive Neuromuscular Facilitation Stretching and Kinesiology Taping on Pelvic Compensation During Double-Knee Extension

    PubMed Central

    Lee, Seung-Woong; Lee, Jung-Hoon

    2015-01-01

    Shortened hamstrings are likely to restrict the anterior pelvic tilt and induce a slumped posture due to the posterior pelvic tilt. This study was conducted to compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and modified anterior pelvic tilt taping (APTT) on hamstring shortness-associated pelvic compensation while executing seated double-knee extension. Male college students (28 healthy young adults; mean age: 21.4 ± 2.1 years) with hamstring shortness were recruited as study subjects and randomly assigned to either the PNF stretching group (control group) or the APTT group (experimental group). In all the subjects, changes in the movement distance of the centre of gluteal pressure (COGP) as well as rectus abdominis (RA) and semitendinosus (SEM) muscle activities were measured during seated double-knee extension while the respective intervention method was applied. Both groups showed significant decreases in COGP distance and RA muscle activity compared with their respective baseline values (p < 0.05), however, no significant changes were observed in SEM muscle activity. We can infer that not only a direct intervention on the hamstring, such as PNF stretching, but also a modified APTT-mediated pelvic intervention may be used as a method for reducing pelvic compensation induced by hamstring shortness. PMID:26839606

  9. Characteristics of isometric and dynamic strength loss following eccentric exercise-induced muscle damage.

    PubMed

    Byrne, C; Eston, R G; Edwards, R H

    2001-06-01

    Angle-specific isometric strength and angular velocity-specific concentric strength of the knee extensors were studied in eight subjects (5 males and 3 females) following a bout of muscular damaging exercise. One hundred maximal voluntary eccentric contractions of the knee extensors were performed in the prone position through a range of motion from 40 degrees to 140 degrees (0 degrees = full extension) at 1.57 rads(-1). Isometric peak torque was measured whilst seated at 10 degrees and 80 degrees knee flexion, corresponding to short and optimal muscle length, respectively. Isokinetic concentric peak torque was measured at 0.52 and 3.14 rad x s(-1). Plasma creatine kinase (CK) activity was also measured from a fingertip blood sample. These measures were taken before, immediately after and on days 1, 2, 4, and 7 following the eccentric exercise. The eccentric exercise protocol resuited in a greater relative loss of strength (P< 0.05) at short muscle length (76.3 +/- 2.5% of pre-exercise values) compared to optimal length (82.1 +/- 2.7%). There were no differences in the relative strength loss between isometric strength at optimal length and isokinetic concentric strength at 0.52 and 3.14 rad x s(-1). CK activity was significantly elevated above baseline at days 4 (P < 0.01) and 7 (P < 0.01). The greater relative strength loss at short muscle length appeared to persist throughout the seven-day testing period and provides indirect evidence of a shift in the angle-torque relationship towards longer muscle lengths. The results lend partial support to the popping sarcomere hypothesis of muscle damage, but could also be explained by an impairment of activation at short muscle lengths.

  10. 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 ...

  11. Cortical activity differs between position- and force-control knee extension tasks.

    PubMed

    Poortvliet, Peter C; Tucker, Kylie J; Finnigan, Simon; Scott, Dion; Sowman, Paul; Hodges, Paul W

    2015-12-01

    Neural control differs between position- and force-control tasks as evident from divergent effects of fatigue and pain. Unlike force-control tasks, position-control tasks focus on a postural goal to maintain a joint angle. Cortical involvement is suggested to be less during postural control, but whether this differs between position- and force-control paradigms remains unclear. Coherence estimates the functional communication between spatially distinct active regions within the cortex (cortico-cortical coherence; CCC) and between the cortex and muscles (corticomuscular coherence; CMC). We investigated whether cortical involvement differed between force-control and more posturally focused, position-control tasks. Seventeen adults performed position- and force-control knee extensor efforts at a submaximal load (10 % maximum voluntary contraction). Surface electromyography was recorded from the right knee extensor and flexor muscles and brain activity using electroencephalography (EEG). CCC and CMC in the beta (13-30 Hz) and gamma (30-45 Hz) frequency bands were calculated between combinations of intra- and inter-hemispheric pairs of electrodes, and between four EEG electrodes that approximated the left motor cortical area, and right knee extensor EMG, respectively. Differences in EEG power and muscle activity were also calculated. CCC was greater across distributed regions in the force-control task. Beta EEG power in the left hemisphere was higher for the position-control task. Although averaged CMC data differed between tasks, there was no task difference for individual CMC data. Muscle activity and force did not differ between tasks. The results demonstrate differential cortical contributions to control force- versus position-control tasks. This might contribute to differences in performance outcomes of these tasks that have been shown previously.

  12. Simultaneous Knee Extensor Muscle Action Induces an Increase in Voluntary Force Generation of Plantar Flexor Muscles.

    PubMed

    Suzuki, Takahito; Shioda, Kohei; Kinugasa, Ryuta; Fukashiro, Senshi

    2017-02-01

    Suzuki, T, Shioda, K, Kinugasa, R, and Fukashiro, S. Simultaneous knee extensor muscle action induces an increase in voluntary force generation of plantar flexor muscles. J Strength Cond Res 31(2): 365-371, 2017-Maximum activation of the plantar flexor muscles is required for various sporting activities that involve simultaneous plantar flexion and knee extension. During a multi-joint movement, activation of the plantar flexor muscles is affected by the activity of the knee extensor muscles. We hypothesized that coactivation of the plantar flexor muscles and knee extensor muscles would result in a higher plantar flexion torque. To test this hypothesis, 8 male volunteers performed maximum voluntary isometric action of the plantar flexor muscles with and without isometric action of the knee extensor muscles. Surface electromyographic data were collected from 8 muscles of the right lower limb. Voluntary activation of the triceps surae muscles, evaluated using the interpolated twitch technique, significantly increased by 6.4 percentage points with intentional knee extensor action (p = 0.0491). This finding is in line with a significant increase in the average rectified value of the electromyographic activity of the vastus lateralis, fibularis longus, and soleus muscles (p = 0.013, 0.010, and 0.045, respectively). The resultant plantar flexion torque also significantly increased by 11.5% of the predetermined maximum (p = 0.031). These results suggest that higher plantar flexor activation coupled with knee extensor activation facilitates force generation during a multi-joint task.

  13. The functional anatomy of the iliotibial band during flexion and extension of the knee: implications for understanding iliotibial band syndrome

    PubMed Central

    Fairclough, John; Hayashi, Koji; Toumi, Hechmi; Lyons, Kathleen; Bydder, Graeme; Phillips, Nicola; Best, Thomas M; Benjamin, Mike

    2006-01-01

    Iliotibial band (ITB) syndrome is a common overuse injury in runners and cyclists. It is regarded as a friction syndrome where the ITB rubs against (and ‘rolls over’) the lateral femoral epicondyle. Here, we re-evaluate the clinical anatomy of the region to challenge the view that the ITB moves antero-posteriorly over the epicondyle. Gross anatomical and microscopical studies were conducted on the distal portion of the ITB in 15 cadavers. This was complemented by magnetic resonance (MR) imaging of six asymptomatic volunteers and studies of two athletes with acute ITB syndrome. In all cadavers, the ITB was anchored to the distal femur by fibrous strands, associated with a layer of richly innervated and vascularized fat. In no cadaver, volunteer or patient was a bursa seen. The MR scans showed that the ITB was compressed against the epicondyle at 30° of knee flexion as a consequence of tibial internal rotation, but moved laterally in extension. MR signal changes in the patients with ITB syndrome were present in the region occupied by fat, deep to the ITB. The ITB is prevented from rolling over the epicondyle by its femoral anchorage and because it is a part of the fascia lata. We suggest that it creates the illusion of movement, because of changing tension in its anterior and posterior fibres during knee flexion. Thus, on anatomical grounds, ITB overuse injuries may be more likely to be associated with fat compression beneath the tract, rather than with repetitive friction as the knee flexes and extends. PMID:16533314

  14. Muscle activation and blood flow do not explain the muscle length-dependent variation in quadriceps isometric endurance.

    PubMed

    Kooistra, R D; de Ruiter, C J; de Haan, A

    2005-03-01

    We investigated the role of central activation in muscle length-dependent endurance. Central activation ratio (CAR) and rectified surface electromyogram (EMG) were studied during fatigue of isometric contractions of the knee extensors at 30 and 90 degrees knee angles (full extension = 0 degree). Subjects (n = 8) were tested on a custom-built ergometer. Maximal voluntary isometric knee extension with supramaximal superimposed burst stimulation (three 100-mus pulses; 300 Hz) was performed to assess CAR and maximal torque capacity (MTC). Surface EMG signals were obtained from vastus lateralis and rectus femoris muscles. At each angle, intermittent (15 s on 6 s off) isometric exercise at 50% MTC with superimposed stimulation was performed to exhaustion. During the fatigue task, a sphygmomanometer cuff around the upper thigh ensured full occlusion (400 mmHg) of the blood supply to the knee extensors. At least 2 days separated fatigue tests. MTC was not different between knee angles (30 degrees : 229.6 +/- 39.3 N.m vs. 90 degrees: 215.7 +/- 13.2 N.m). Endurance times, however, were significantly longer (P < 0.05) at 30 vs. 90 degrees (87.8 +/- 18.7 vs. 54.9 +/- 12.1 s, respectively) despite the CAR not differing between angles at torque failure (30 degrees: 0.95 +/- 0.05 vs. 90 degrees: 0.96 +/- 0.03) and full occlusion of blood supply to the knee extensors. Furthermore, rectified surface EMG values of the vastus lateralis (normalized to prefatigue maximum) were also similar at torque failure (30 degrees : 56.5 +/- 12.5% vs. 90 degrees : 58.3 +/- 15.2%), whereas rectus femoris EMG activity was lower at 30 degrees (44.3 +/- 12.4%) vs. 90 degrees (69.5 +/- 25.3%). We conclude that differences in endurance at different knee angles do not find their origin in differences in central activation and blood flow but may be a consequence of muscle length-related differences in metabolic cost.

  15. The effective mechanical advantage of a.L. 129-1a for knee extension.

    PubMed

    Sylvester, Adam D; Mahfouz, Mohamed R; Kramer, Patricia Ann

    2011-09-01

    The functional significance of shape differences between modern human and australopithecine distal femora remains unclear. Here, we examine the morphological component of the effective mechanical advantage (EMA) of the quadriceps muscle group in a sample of hominins that includes the fossil A.L. 129-1a (Australopithecus afarensis) and modern humans. Quadriceps muscle moment arms were calculated from three-dimensional computer models of specimens through a range of knee flexion. All hominins were compared using the same limb positions to allow us to examine, in isolation, the morphological component of the lengths of the pertinent moment arms. After taking into account the differences in bicondylar angle, the morphological component of the EMA was calculated as the ratio of the quadriceps muscle and ground reaction force moment arms. Our analyses reveal that A.L. 129-1a would have possessed a morphological component of the quadriceps muscle EMA expected for a hominin of its body mass.

  16. Reduced activation in isometric muscle action after lengthening contractions is not accompanied by reduced performance fatigability

    PubMed Central

    Seiberl, W.; Hahn, D.; Paternoster, F. K.

    2016-01-01

    After active lengthening contractions, a given amount of force can be maintained with less muscle activation compared to pure isometric contractions at the same muscle length and intensity. This increase in neuromuscular efficiency is associated with mechanisms of stretch-induced residual force enhancement. We hypothesized that stretch-related increase in neuromuscular efficiency reduces fatigability of a muscle during submaximal contractions. 13 subjects performed 60 s isometric knee extensions at 60% of maximum voluntary contraction (MVC) with and without prior stretch (60°/s, 20°). Each 60 s trial was preceded and followed by neuromuscular tests consisting of MVCs, voluntary activation (VA) and resting twitches (RT), and there was 4 h rest between sets. We found a significant (p = 0.036) 10% reduction of quadriceps net-EMG after lengthening compared to pure isometric trials. However, increase in neuromuscular efficiency did not influence the development of fatigue. Albeit we found severe reduction of MVC (30%), RT (30%) and VA (5%) after fatiguing trials, there were no differences between conditions with and without lengthening. As the number of subjects showing no activation reduction increased with increasing contraction time, intensity may have been too strenuous in both types of contractions, such that a distinction between different states of fatigue was not possible anymore. PMID:27966620

  17. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task

    PubMed Central

    Laubacher, Marco; Aksöz, Efe A.; Binder-Macleod, Stuart; Hunt, Kenneth J.

    2016-01-01

    Spatially distributed sequential stimulation (SDSS) has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES) in the application of functional electrical stimulation (FES). This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14). Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak) were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s). The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively). With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively) but of longer activation time (p=0.096). The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable. PMID:27478563

  18. Is the Modified Tardieu Scale in Semi-Standing Position Better Associated with Knee Extension and Hamstring Activity in Terminal Swing than the Supine Tardieu?

    ERIC Educational Resources Information Center

    Faber, Irene R.; Nienhuis, Bart; Rijs, Nique P. A. M.; Geurts, Alexander C. H.; Duysens, Jacques

    2008-01-01

    The aim of this study was to investigate whether the modified Tardieu scale (MTS) in a semi-standing position, used for the assessment of hamstrings spasticity, was better associated with knee extension and hamstrings activity in terminal swing than the MTS in a supine position in children with cerebral palsy (CP). Seven children diagnosed with…

  19. The validity of an assessment of maximum angular velocity of knee extension (KE) using a gyroscope.

    PubMed

    Arai, Takeshi; Obuchi, Shuichi; Shiba, Yoshitaka; Omuro, Kazuya; Inaba, Yasuko; Kojima, Motonaga

    2012-01-01

    Although it is more important to assess the muscular power of the lower extremities than the strength, no simplified method for doing so has been found. The aim of this study was to assess the validity of the assessment of the angular velocity of KE using a gyroscope. Participants included 105 community-dwelling older people (55 women, 50 men, age ± standard deviation (SD) 75±5.3). Pearson correlation coefficients and Spearman rank-correlation coefficients were used to examine the relationships between the angular velocity of KE and functional performance measurements, a self-efficacy scale and health-related quality of life (HRQOL). The data from the gyroscope were significantly correlated with some physical functions such as muscle strength (r=0.304, p<0.01), and walking velocity (r=0.543, p<0.001). In addition, the joint angular velocity was significantly correlated with self-efficacy (r=0.219-0.329, p<0.01-0.05) and HRQOL (r=0.207-0.359, p<0.01-0.05). The absolute value of the correlation coefficient of angular velocity tended to be greater than that of the muscle strength for mobility functions such as walking velocity and the timed-up-and-go (TUG) test. In conclusion, it was found that the assessment of the angular velocity of the knee joint using a gyroscope could be a feasible and meaningful measurement in the geriatrics field.

  20. Comparison of skin sympathetic nerve responses to isometric arm and leg exercise.

    PubMed

    Ray, Chester A; Wilson, Thad E

    2004-07-01

    Measurement of skin sympathetic nerve activity (SSNA) during isometric exercise has been previously limited to handgrip. We hypothesized that isometric leg exercise due to the greater muscle mass of the leg would elicit greater SSNA responses than arm exercise because of presumably greater central command and muscle mechanoreceptor activation. To compare the effect of isometric arm and leg exercise on SSNA and cutaneous end-organ responses, 10 subjects performed 2 min of isometric knee extension (IKE) and handgrip (IHG) at 30% of maximal voluntary contraction followed by 2 min of postexercise muscle ischemia (PEMI) in a normothermic environment. SSNA was recorded from the peroneal nerve. Cutaneous vascular conductance (laser-Doppler flux/mean arterial pressure) and electrodermal activity were measured within the field of cutaneous afferent discharge. Heart rate and mean arterial pressure significantly increased by 16 +/- 3 and 23 +/- 3 beats/min and by 22 +/- 2 and 27 +/- 3 mmHg from baseline during IHG and IKE, respectively. Heart rate and mean arterial pressure responses were significantly greater during IKE compared with IHG. SSNA increased significantly and comparably during IHG and IKE (52 +/- 20 and 50 +/- 13%, respectively). During PEMI, SSNA and heart rate returned to baseline, whereas mean arterial pressure remained significantly elevated (Delta12 +/- 2 and Delta13 +/- 2 mmHg from baseline for IHG and IKE, respectively). Neither cutaneous vascular conductance nor electrodermal activity was significantly altered by either exercise or PEMI. These results indicate that, despite cardiovascular differences in response to IHG and IKE, SSNA responses are similar at the same exercise intensity. Therefore, the findings suggest that relative effort and not muscle mass is the main determinant of exercise-induced SSNA responses in humans.

  1. Computational biomechanics of knee joint in open kinetic chain extension exercises.

    PubMed

    Mesfar, W; Shirazi-Adl, A

    2008-02-01

    Open kinetic chain (OKC) extension exercises are commonly performed to strengthen quadriceps muscles and restore joint function in performance enhancement programs, in exercise therapies and following joint reconstruction. Using a validated 3D nonlinear finite element model, the detailed biomechanics of the entire joint in OKC extension exercises are investigated at 0, 30, 60 and 90 degrees joint angles. Two loading cases are simulated; one with only the weight of the leg and the foot while the second considers also a moderate resistant force of 30 N acting at the ankle perpendicular to the tibia. The presence of the 30 N markedly influences the results both in terms of the magnitude and the trend. The resistant load substantially increases the required quadriceps, patellar tendon, cruciate ligaments and joint contact forces, especially at near 90 degrees angles with the exception of ACL force that is increased at 0 degrees angle. At post-ACL reconstruction period or in the joint with ACL injury, the exercise should preferably be avoided at near full extension positions under large resistant forces.

  2. Measurement of knee joint gaps without bone resection: "physiologic" extension and flexion gaps in total knee arthroplasty are asymmetric and unequal and anterior and posterior cruciate ligament resections produce different gap changes.

    PubMed

    Nowakowski, Andrej Maria; Majewski, Martin; Müller-Gerbl, Magdalena; Valderrabano, Victor

    2012-04-01

    General agreement is that flexion and extension gaps should be equal and symmetrical in total knee arthroplasty (TKA) procedures. However, comparisons using a standard TKA approach to normal knee joints that have not undergone bone resection are currently unavailable. Since bony preparation can influence capsule and ligament tension, our purpose was to perform measurements without this influence. Ten normal cadaveric knees were assessed using a standard medial parapatellar TKA approach with patellar subluxation. Gap measurements were carried out twice each alternating 100 and 200 N per compartment using a prototypical force-determining ligament balancer without the need for bony resection. Initial measurements were performed in extension, followed by 908 of flexion. The ACL was then resected, and finally the PCL was resected, and measurements were carried out in an analogous fashion. In general, the lateral compartment could be stretched further than the medial compartment, and the corresponding flexion gap values were significantly larger. ACL resection predominantly increased extension gaps, while PCL resection increased flexion gaps. Distraction force of 100 N per compartment appeared adequate; increasing to 200 N did not improve the results.

  3. A comparison of volume-equated knee extensions to failure, or not to failure, upon rating of perceived exertion and strength adaptations.

    PubMed

    Fisher, James Peter; Blossom, Dominic; Steele, James

    2016-02-01

    The present study aimed to compare the effects of repetition duration-, volume-, and load-matched resistance training to muscular failure (MMF) or not to muscular failure (NMF) on maximal voluntary isometric knee extensor strength. This design also allowed testing of the efficacy of "5×5" training. Nine recreationally active males (age, 21.4 ± 1.2 years; height, 1.79 ± 0.07 m; weight, 78.4 ± 7.1 kg) performed unilateral resistance training at 80% of maximal torque at 2×/week for 6 weeks. Using their nondominant leg, participants performed 5 sets of 5 repetitions (NMF). Using their dominant leg, participants performed 25 repetitions in as few sets as possible (MMF). All repetitions were performed at a pace of 2 s concentric, 1 s isometric pause, and 2 s eccentric with a 2-min rest interval between sets. Analyses identified significant pre- to post-intervention strength increases for both MMF and NMF, with effect sizes (ESs) of 2.01 and 1.65, respectively, with no significant differences between conditions (p > 0.05). Peak and mean ratings of perceived exertion (RPEs) were significantly higher for MMF compared with NMF conditions (p < 0.0001), and a tendency for significantly higher RPE values reported for later sets for the NMF condition. Total training time per session was significantly longer for NMF compared with MMF (p < 0.001). The present study suggests that in untrained participants, resistance training NMF produces equivocally the same strength increases as training to MMF when volume-matched. However, resistance training to MMF appears to be a more time-efficient protocol and may produce greater strength gains as indicated by a larger ES.

  4. The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Unilateral Knee Extension Eccentric Exercise.

    PubMed

    Legault, Zachary; Bagnall, Nicholas; Kimmerly, Derek S

    2015-10-01

    The study aimed to examine the effects that L-glutamine supplementation has on quadriceps muscle strength and soreness ratings following eccentric exercise. It was hypothesized that glutamine ingestion would quicken the recovery rate of peak force production and decrease muscle soreness ratings over a 72-hr recovery period. Sixteen healthy participants (8♀/8♂; 22 ± 4 years) volunteered in a double-blind, randomized, placebo-controlled crossover study. Supplement conditions consisted of isoenergetic placebo (maltodextrin, 0.6 g·kg-1·day-1) and L-glutamine (0.3 g·kg-1·day-1 + 0.3 g·kg-1·day-1 maltodextrin) ingestion once per day over 72 hr. Knee extensor peak torque at 0°, 30°, and 180° per second and muscle soreness were measured before, immediately following, 24, 48, and 72 hr posteccentric exercise. Eccentric exercise consisted of 8 sets (10 repetitions/set) of unilateral knee extension at 125% maximum concentric force with 2-min rest intervals. L-glutamine resulted in greater relative peak torque at 180°/sec both immediately after (71 ± 8% vs. 66 ± 9%), and 72 hr (91 ± 8% vs. 86 ± 7%) postexercise (all, p < .01). In men, L-glutamine produced greater (p < .01) peak torques at 30°/ sec postexercise. Men also produced greater normalized peak torques at 30°/sec (Nm/kg) in the L-glutamine condition than women (all, p < .05). In the entire sample, L-glutamine resulted in lower soreness ratings at 24 (2.8 ± 1.2 vs. 3.4 ± 1.2), 48 (2.6 ± 1.4 vs. 3.9 ± 1.2), and 72 (1.7 ± 1.2 vs. 2.9 ± 1.3) hr postexercise (p < .01). The L-glutamine supplementation resulted in faster recovery of peak torque and diminished muscle soreness following eccentric exercise. The effect of L-glutamine on muscle force recovery may be greater in men than women.

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

    PubMed Central

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

    2011-01-01

    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 < 0.05), whereas the coefficient of variation was highest in VL (VL vs VI, p < 0.05). Coefficient of variation between the mean values of the four 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

  6. Knee Power Is an Important Parameter in Understanding Medial Knee Joint Load in Knee Osteoarthritis

    PubMed Central

    Calder, Kristina M; Acker, Stacey M; Arora, Neha; Beattie, Karen A; Callaghan, Jack P; Adachi, Jonathan D; Maly, Monica R

    2014-01-01

    Objective To determine the extent to which knee extensor strength and power explain variance in knee adduction moment (KAM) peak and impulse in clinical knee osteoarthritis (OA). Methods Fifty-three adults (mean ± SD age 61.6 ± 6.3 years, 11 men) with clinical knee OA participated. The KAM waveform was calculated from motion and force data and ensemble averaged from 5 walking trials. The KAM peak was normalized to body mass (Nm/kg). The mean KAM impulse reflected the mean total medial knee load during stride (Nm × seconds). For strength, the maximum knee extensor moment attained from maximal voluntary isometric contractions (MVIC) was normalized to body mass (Nm/kg). For power, the maximum knee extensor power during isotonic contractions, with the resistance set at 25% of MVIC, was normalized to body mass (W/kg). Covariates included age, sex, knee pain on the Knee Injury and Osteoarthritis Outcome Score, gait speed, and body mass index (BMI). Relationships of the KAM peak and impulse with strength and power were examined using sequential stepwise forward linear regressions. Results Covariates did not explain variance in the KAM peak. While extensor strength did not, peak knee extensor power explained 8% of the variance in the KAM peak (P = 0.02). Sex and BMI explained 24% of the variance in the KAM impulse (P < 0.05). Sex, BMI, and knee extensor power explained 31% of the variance in the KAM impulse (P = 0.02), with power contributing 7% (P < 0.05). Conclusion Knee extensor power was more important than isometric knee strength in understanding medial knee loads during gait. PMID:24920175

  7. Knee angle-dependent oxygen consumption of human quadriceps muscles during maximal voluntary and electrically evoked contractions.

    PubMed

    Kooistra, R D; de Ruiter, C J; de Haan, A

    2008-01-01

    Fatigability and muscle oxygen consumption (mVO(2)) during sustained voluntary isometric knee extensions are less at extended (30 degrees knee angle; 0 degrees , full extension) versus flexed knee angles (90 degrees). This lower energy consumption may partially result from lower neural activation at extended knee angles. We hypothesized a smaller difference in mVO(2) between extended and flexed knee angles during electrical stimulation, which guaranteed maximal activation, than during maximal voluntary contractions (MVC). In eight healthy young males, MVC extension torque was obtained at 30 degrees, 60 degrees and 90 degrees knee angles. mVO(2) of the rectus femoris (RF), vastus lateralis (VL) and medialis muscle was measured using near-infrared spectroscopy during tetanic (10 s) and maximal voluntary (15 s) contractions (MVC(15)). For electrically induced contractions, steady state mVO(2) was reached at similar (P > 0.05) times after torque onset (4.6 +/- 0.7 s) at all knee angles. In contrast, during MVC(15) at 30 degrees mVO(2) was reached at 7.1 +/- 1.1 s, significantly later compared to 60 degrees and 90 degrees knee angles. The knee angle dependent differences in mVO(2) were not lower in electrically induced contractions (as hypothesised) but were similar as in voluntary contractions. Normalized mVO(2) at 30 degrees (percentage 90 degrees knee angle) was 79.0 +/- 9.4% (across muscles) for electrically induced and 79.5 +/- 7.6% (across muscles) for voluntary contractions (P < 0.05). We conclude that the slower onset of mVO(2) during voluntary effort at 30 degrees may have been due to a lower maximal activation. However, because steady state mVO(2) both during electrically induced and voluntary contractions was approximately 20% less at extended versus flexed knee angles, the causes for the lower mVO(2) must reside within the muscle itself.

  8. Skeletal muscle ATP turnover by 31P magnetic resonance spectroscopy during moderate and heavy bilateral knee extension

    PubMed Central

    Cannon, Daniel T; Bimson, William E; Hampson, Sophie A; Bowen, T Scott; Murgatroyd, Scott R; Marwood, Simon; Kemp, Graham J; Rossiter, Harry B

    2014-01-01

    During constant-power high-intensity exercise, the expected increase in oxygen uptake () is supplemented by a  slow component (), reflecting reduced work efficiency, predominantly within the locomotor muscles. The intracellular source of inefficiency is postulated to be an increase in the ATP cost of power production (an increase in P/W). To test this hypothesis, we measured intramuscular ATP turnover with 31P magnetic resonance spectroscopy (MRS) and whole-body during moderate (MOD) and heavy (HVY) bilateral knee-extension exercise in healthy participants (n = 14). Unlocalized 31P spectra were collected from the quadriceps throughout using a dual-tuned (1H and 31P) surface coil with a simple pulse-and-acquire sequence. Total ATP turnover rate (ATPtot) was estimated at exercise cessation from direct measurements of the dynamics of phosphocreatine (PCr) and proton handling. Between 3 and 8 min during MOD, there was no discernable (mean ± SD, 0.06 ± 0.12 l min−1) or change in [PCr] (30 ± 8 vs. 32 ± 7 mm) or ATPtot (24 ± 14 vs. 17 ± 14 mm min−1; each P = n.s.). During HVY, the was 0.37 ± 0.16 l min−1 (22 ± 8%), [PCr] decreased (19 ± 7 vs. 18 ± 7 mm, or 12 ± 15%; P < 0.05) and ATPtot increased (38 ± 16 vs. 44 ± 14 mm min−1, or 26 ± 30%; P < 0.05) between 3 and 8 min. However, the increase in ATPtot (ΔATPtot) was not correlated with the during HVY (r2 = 0.06; P = n.s.). This lack of relationship between ΔATPtot and , together with a steepening of the [PCr]– relationship in HVY, suggests that reduced work efficiency during heavy exercise arises from both contractile (P/W) and mitochondrial sources (the O2 cost of ATP resynthesis; P/O). PMID:25281731

  9. A new isometric quadriceps-strengthening exercise using EMG-biofeedback

    PubMed Central

    Kesemenli, Cumhur C; Sarman, Hakan; Baran, Tuncay; Memisoglu, Kaya; Binbir, Ismail; Savas, Yilmaz; Isik, Cengiz; Boyraz, Ismail; Koc, Bunyamin

    2014-01-01

    A new isometric contraction quadriceps-strengthening exercise was developed to restore the quadriceps strength lost after knee surgery more rapidly. This study evaluated the results of this new method. Patients were taught to perform the isometric quadriceps-strengthening exercise in the unaffected knee in the supine position, and then they performed it in the affected knee. First, patients were taught the classical isometric quadriceps-strengthening exercise, and then they were taught our new alternative method: “pull the patella superiorly tightly and hold the leg in the same position for 10 seconds”. Afterward, the quadriceps contraction was evaluated using a non-invasive Myomed 932 EMG-biofeedback device (Enraf-Nonius, The Netherlands) with gel-containing 48 mm electrodes (Türklab, The Turkey) placed on both knees. The isometric quadriceps-strengthening exercise performed using our new method had stronger contraction than the classical method (P < 0.01). The new method involving pulling the patella superiorly appears to be a better choice, which can be applied easily, leading to better patient compliance and greater quadriceps force after arthroscopic and other knee surgeries. PMID:25356122

  10. Effect of increased maxillo-mandibular relationship on isometric strength in TMD patients with loss of vertical dimension of occlusion.

    PubMed

    Abduljabbar, T; Mehta, N R; Forgione, A G; Clark, R E; Kronman, J H; Munsat, T L; George, P

    1997-01-01

    The effect on isometric strength of the shoulders and limbs while biting in habitual occlusion, on a bite-elevating appliance and on a placebo appliance was analyzed. Twenty female volunteer patients, presenting with temporomandibular pain dysfunction syndrome and obvious loss of vertical dimension, served as subjects. All were weaker to the manual application of the isometric Deltoid Press (IDP) when biting, as opposed to maintaining the mandible in an unsupported rest position. Two intraoral appliances were fabricated for each subject: a bite-elevating appliance (BEA) set by a functional criterion of peak strength to the IDP and a placebo appliance which did not interfere with occlusion but was "set" with a mock IDP procedure. Testing was carried out by the Neuromuscular Research Testing Laboratory of the Neurology Department of Tufts New England Medical Center. Testing was independent of the dentist who fabricated and set the appliances. A standard neuromuscular test with the Maximal Voluntary Isometric Contraction apparatus was used to assess strength of right and left shoulder, elbow and knee flexion and extension as is routinely performed with all neuromuscular disease patients. Twelve strength tests were carried out for each of three conditions: 1. Baseline-biting in habitual occlusion; 2. Elevated-biting on the BEA; and 3. Placebo-biting with the placebo appliance inserted. The order of conditions 2 and 3 was counterbalanced without knowledge of the subjects. Twelve repeated measures ANOVAs (each subject as their own control) were conducted for each of the 12 strength measures. All F-tests indicated a significant main effect for treatment differences (p < 0.0001). Mean strength biting on the BEA was consistantly greater (p < 0.001) than Baseline or Placebo strength. Baseline and Placebo condition were equivalent. These findings confirmed previous observations at this TMD Center: individuals with loss of vertical dimension of occlusion respond to a bite

  11. Older men are more fatigable than young when matched for maximal power and knee extension angular velocity is unconstrained.

    PubMed

    Dalton, Brian H; Power, Geoffrey A; Paturel, Justin R; Rice, Charles L

    2015-06-01

    The underlying factors related to the divergent findings of age-related fatigue for dynamic tasks are not well understood. The purpose here was to investigate age-related fatigability and recovery between a repeated constrained (isokinetic) and an unconstrained velocity (isotonic) task, in which participants performed fatiguing contractions at the velocity (isokinetic) or resistance (isotonic) corresponding with maximal power. To compare between tasks, isotonic torque-power relationships were constructed prior to and following both fatiguing tasks and during short-term recovery. Contractile properties were recorded from 9 old (~75 years) and 11 young (~25 years) men during three testing sessions. In the first session, maximal power was assessed, and sessions 2 and 3 involved an isokinetic or an isotonic concentric fatigue task performed until maximal power was reduced by 40 %. Compared with young, the older men performed the same number of contractions to task failure for the isokinetic task (~45 contractions), but 20 % fewer for the isotonic task (p < 0.05). Regardless of age and task, maximal voluntary isometric contraction strength, angular velocity, and power were reduced by ~30, ~13, and ~25 %, respectively, immediately following task failure, and only isometric torque was not recovered fully by 10 min. In conclusion, older men are more fatigable than the young when performing a repetitive maximal dynamic task at a relative resistance (isotonic) but not an absolute velocity (isokinetic), corresponding to maximal power.

  12. Relationships between Isometric Muscle Strength, Gait Parameters, and Gross Motor Function Measure in Patients with Cerebral Palsy

    PubMed Central

    Shin, Hyung-Ik; Sung, Ki Hyuk; Chung, Chin Youb; Lee, Kyoung Min; Lee, Seung Yeol; Lee, In Hyeok

    2016-01-01

    Purpose This study investigated the correlation between isometric muscle strength, gross motor function, and gait parameters in patients with spastic cerebral palsy and to find which muscle groups play an important role for gait pattern in a flexed knee gait. Materials and Methods Twenty-four ambulatory patients (mean age, 10.0 years) with spastic cerebral palsy who were scheduled for single event multilevel surgery, including distal hamstring lengthening, were included. Preoperatively, peak isometric muscle strength was measured for the hip flexor, hip extensor, knee flexor, and knee extensor muscle groups using a handheld dynamometer, and three-dimensional (3D) gait analysis and gross motor function measure (GMFM) scoring were also performed. Correlations between peak isometric strength and GMFM, gait kinematics, and gait kinetics were analyzed. Results Peak isometric muscle strength of all muscle groups was not related to the GMFM score and the gross motor function classification system level. Peak isometric strength of the hip extensor and knee extensor was significantly correlated with the mean pelvic tilt (r=-0.588, p=0.003 and r=-0.436, p=0.033) and maximum pelvic obliquity (r=-0.450, p=0.031 and r=-0.419, p=0.041). There were significant correlations between peak isometric strength of the knee extensor and peak knee extensor moment in early stance (r=0.467, p=0.021) and in terminal stance (r=0.416, p=0.043). Conclusion There is no correlation between muscle strength and gross motor function. However, this study showed that muscle strength, especially of the extensor muscle group of the hip and knee joints, might play a critical role in gait by stabilizing pelvic motion and decreasing energy consumption in a flexed knee gait. PMID:26632404

  13. Runner's Knee

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Runner's Knee KidsHealth > For Teens > Runner's Knee A A A ... told he had runner's knee. What Is Runner's Knee? Runner's knee is the term doctors use for ...

  14. Knee pain

    MedlinePlus

    Pain - knee ... Knee pain can have different causes. Being overweight puts you at greater risk for knee problems. Overusing your knee can trigger knee problems that cause pain. If you have a history of arthritis, it ...

  15. Trunk biomechanics and its association with hip and knee kinematics in patients with and without patellofemoral pain.

    PubMed

    Nakagawa, Theresa Helissa; Maciel, Carlos Dias; Serrão, Fábio Viadanna

    2015-02-01

    Patellofemoral pain (PFP) is a common lower extremity condition observed in sports clinics. Recently, it has been suggested that trunk motion could affect hip and knee biomechanics in the frontal plane. Thus, the purpose of the study was compare trunk kinematics, strength and muscle activation between people with PFP and healthy participants. In addition, the associations among trunk biomechanics, hip and knee kinematics were analysed. Thirty people with PFP and thirty pain-free individuals participated. The peak ipsilateral trunk lean, hip adduction, and knee abduction were evaluated with an electromagnetic tracking system, and the surface electromyographic signals of the iliocostalis and external oblique muscle were recorded during single-leg squats. Trunk extension and trunk flexion with rotation isometric strength and side bridge tests were quantified using a handheld dynamometer. Compared with the control group, the PFP group demonstrated increased ipsilateral trunk lean, hip adduction and knee abduction (p = 0.02-0.04) during single-leg squat accompanied with decreased trunk isometric strength (p = < 0.001-0.009). There was no between-group difference in trunk muscle activation. Only in the control group, ipsilateral trunk lean was significantly correlated with hip adduction (r = -0.66) and knee abduction (r = 0.49); also, the side bridge test correlated with knee abduction (r = -0.51). Differences in trunk, hip and knee biomechanics were found in people with PFP. No relationship among trunk, hip and knee biomechanics was found in the PFP group, suggesting that people with PFP show different movement patterns compared to the control group.

  16. Quadriceps Rate of Force Development affects Gait and Function in People with Knee Osteoarthritis

    PubMed Central

    Winters, Joshua D.; Rudolph, Katherine S.

    2014-01-01

    Objective Quadriceps weakness exists in people with knee osteoarthritis (OA) but other muscle factors like rate of force development (RFD) may also be affected by knee OA. The purpose of this study was to determine if people with knee OA have deficits in quadriceps RFD, determine if quadriceps RFD would improve predicting knee joint power absorption and generation during free and fast walking, and determine if RFD would improve predicting functional outcomes. Methods 26 subjects with knee OA and 23 healthy control subjects performed maximal voluntary isometric strength (MVIC) and RFD measures of the quadriceps. Subjects also underwent a 3-D motion analysis of both self-selected free and self-selected fast walking speeds. Joint kinetics were calculated from inverse dynamics. Results RFD was not different by group (p=0.763), however the OA subjects generated the highest peak RFD at a lower %MVIC (p=0.008). Controls walked significantly faster at both free and fast walking speeds (p=0.001, p=0.029). Knee angles at heel strike and peak knee extension were lower (p=0.004, p=0.027) in the OA group. During fast walking knee power generation was higher in Controls (p=0.028). MVIC and force of highest peak RFD predicted KOOS ADL score in the OA subjects, but only MVIC predicted stair climbing time. Conclusions The submaximal force at which peak RFD occurs plays a significant role in knee joint power as well as functional measures in the OA subjects, providing further evidence that factors other than maximal strength are also important in people with knee OA. PMID:24240535

  17. Angle- and gender-specific quadriceps femoris muscle recruitment and knee extensor torque.

    PubMed

    Pincivero, Danny M; Salfetnikov, Yuliya; Campy, Robert M; Coelho, Alan J

    2004-11-01

    The objectives were to examine knee angle-, and gender-specific knee extensor torque output and quadriceps femoris (QF) muscle recruitment during maximal effort, voluntary contractions. Fourteen young adult men and 15 young adult women performed three isometric maximal voluntary contractions (MVC), in a random order, with the knee at 0 degrees (terminal extension), 10 degrees, 30 degrees, 50 degrees, 70 degrees, and 90 degrees flexion. Knee extensor peak torque (PT), and average torque (AT) were expressed in absolute (N m), relative (N m kg(-1)) and allometric-modeled (N m kg(-n)) units. Vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle EMG signals were full-wave rectified and integrated over the middle 3 s of each contraction, averaged over the three trials at each knee angle, and normalized to the activity recorded at 0 degrees. Muscle recruitment efficiency was calculated as the ratio of the normalized EMG of each muscle to the allometric-modeled average torque (normalized to the values at 0 degrees flexion), and expressed as a percent. Men generated significantly greater knee extensor PT and AT than women in absolute, relative and allometric-modeled units. Absolute and relative PT and AT were significantly highest at 70 degrees, while allometric-modeled values were observed to increase significantly across knee joint angles 10-90 degrees. VM EMG was significantly greater than the VL and RF muscles across all angles, and followed a similar pattern to absolute knee extensor torque. Recruitment efficiency improved across knee joint angles 10-90 degrees and was highest for the VL muscle. VM recruitment efficiency improved more than the VL and RF muscles across 70-90 degrees flexion. The findings demonstrate angle-, and gender-specific responses of knee extensor torque to maximal-effort contractions, while superficial QF muscle recruitment was most efficient at 90 degrees, and less dependent on gender.

  18. 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

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

    2001-01-01

    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

  19. REHABILITATION AND FUNCTIONAL OUTCOMES AFTER EXTENSIVE SURGICAL DEBRIDEMENT OF A KNEE INFECTED BY FUSOBACTERIUM NECROPHORUM: A CASE REPORT

    PubMed Central

    Briggs, Matthew S.; Kegelmeyer, Deborah K.; Kloos, Anne D.

    2013-01-01

    Background and Purpose: Joint infection is a rare but serious complication after knee injury that should be part of a physical therapist's differential diagnosis. This case report presents the care of a 17 year‐old female athlete with septic arthritis from a Fusobacterium infection after sustaining a right lateral meniscus tear. Joint pathology combined with the aggressive infectious agent led to arthrofibrosis of her knee joint and resultant activity limitations and participation restrictions. The purpose of this case report is to highlight a rare and unique pathology, the serious effects that a joint infection can have on musculoskeletal function, and the challenges encountered during the rehabilitation process. Case Description: The subject was a 17 year‐old volleyball player who injured her right knee while playing volleyball. Within 7 days, the subject developed a severe joint infection that spread into surrounding gluteal, quadriceps, and gastrocnemius musculature. The infection was surgically debrided eight times during a 10‐week inpatient hospital stay. A manipulation under anesthesia was performed to restore range of motion in her knee joint. Outpatient physical therapy was initiated 4 days later in order to restore musculoskeletal function. Outcome: Over eight months of physical therapy services were utilized to address the impairments and activity limitations caused by her joint dysfunction. She met her physical therapy goals and made significant improvements on the Knee Outcome Survey and the Lower Extremity Functional Scale. Success in physical therapy and completion of additional strength training exercise allowed this subject to return to competitive softball at the club level during her freshman year of college. Discussion: Though rare after musculoskeletal injury, joint infection can lead to soft tissue damage, partial or complete degradation of articular cartilage, and arthrofibrosis causing significant disability. Physical therapists must

  20. Effects of Lumbosacral Manipulation on Isokinetic Strength of the Knee Extensors and Flexors in Healthy Subjects: A Randomized, Controlled, Single-Blind Crossover Trial

    PubMed Central

    Sanders, Grant D.; Nitz, Arthur J.; Abel, Mark G.; Symons, T. Brock; Shapiro, Robert; Black, W. Scott; Yates, James W.

    2015-01-01

    Objective The purpose of this study was to investigate the effect of manual manipulations targeting the lumbar spine and/or sacroiliac joint on concentric knee extension and flexion forces. Torque production was measured during isometric and isokinetic contractions. Methods This was a randomized, controlled, single-blind crossover design with 21 asymptomatic, college-aged subjects who had never received spinal manipulation. During 2 separate sessions, subjects’ peak torques were recorded while performing maximal voluntary contractions on an isokinetic dynamometer. Isometric knee extension and flexion were recorded at 60° of knee flexion, in addition to isokinetic measurements obtained at 60°/s and 180°/s. Baseline measurements were acquired before either treatment form of lumbosacral manipulation or sham manipulation, followed by identical peak torque measurements within 5 and 20 minutes posttreatment. Data were analyzed with a repeated measures analysis of variance. Results A statistically significant difference did not occur between the effects of lumbosacral manipulation or the sham manipulation in the percentage changes of knee extension and flexion peak torques at 5 and 20 minutes posttreatment. Similar, nonsignificant results were observed in the overall percentage changes of isometric contractions (spinal manipulation 4.0 ± 9.5 vs sham 1.2 ± 6.3, P = .067), isokinetic contractions at 60°/s (spinal manipulation − 4.0 ± 14.2 vs sham − 0.3 ± 8.2, P = .34), and isokinetic contractions at 180°/s (spinal manipulation − 1.4 ± 13.9 vs sham − 5.5 ± 20.0, P = .18). Conclusion The results of the current study suggest that spinal manipulation does not yield an immediate strength-enhancing effect about the knee in healthy, college-aged subjects when measured with isokinetic dynamometry. PMID:26793035

  1. Isometric push and pull strengths of young Taiwanese males.

    PubMed

    Chen, Yi-Lang; Lee, Yu-Chi; Hsu, Tin-Chi

    2011-01-01

    This study recruited 30 young Taiwanese males to determine the horizontally maximum isometric pushing and pulling strengths under 16 exertion heights and four handle-foot horizontal distances. This study shows that isometric push and pull strengths as measured on a simulated frictional floor condition in Taiwanese hypermarkets were markedly lower than previous tests using high-traction flooring or anchoring participant's feet. Pushing strengths were always higher than pulling in all 64 task combinations, whereas no significant differences were present at heights of 30-60 cm. When considering maximum push and pull force demands, the optimal heights for such activities would be 50-90 cm (approximately ranged from the knee to hip position). The push and pull strength profiles identified in this study must be used appropriately, considering the real task situations.

  2. Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

    PubMed

    Saito, Akira; Akima, Hiroshi

    2013-12-01

    It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG-force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles.

  3. Whole-body vibration does not influence knee joint neuromuscular function or proprioception.

    PubMed

    Hannah, R; Minshull, C; Folland, J P

    2013-02-01

    This study examined the acute effects of whole-body vibration (WBV) on knee joint position sense and indices of neuromuscular function, specifically strength, electromechanical delay and the rate of force development. Electromyography and electrically evoked contractions were used to investigate neural and contractile responses to WBV. Fourteen healthy males completed two treatment conditions on separate occasions: (1) 5 × 1 min of unilateral isometric squat exercise on a synchronous vibrating platform [30 Hz, 4 mm peak-to-peak amplitude] (WBV) and (2) a control condition (CON) of the same exercise without WBV. Knee joint position sense (joint angle replication task) and quadriceps neuromuscular function were assessed pre-, immediately-post and 1 h post-exercise. During maximum voluntary knee extensions, the peak force (PF(V)), electromechanical delay (EMD(V)), rate of force development (RFD(V)) and EMG of the quadriceps were measured. Twitch contractions of the knee extensors were electrically evoked to assess EMD(E) and RFD(E). The results showed no influence of WBV on knee joint position, EMD(V), PF(V) and RFD(V) during the initial 50, 100 or 150 ms of contraction. Similarly, electrically evoked neuromuscular function and neural activation remained unchanged following the vibration exercise. A single session of unilateral WBV did not influence any indices of thigh muscle neuromuscular performance or knee joint proprioception.

  4. Mechanics of the knee. A study of joint and muscle load with clinical applications.

    PubMed

    Nisell, R

    1985-01-01

    The load moment of force about the knee joint during machine milking and when lifting a 12.8 kg box was quantified using a computerized static sagittal plane body model. Surface electromyography of quadriceps and hamstrings muscles was normalized and expressed as a percentage of an isometric maximum voluntary test contraction. Working with straight knees and the trunk flexed forwards induced extending knee load moments of maximum 55 Nm. Lifting the box with flexed knees gave flexing moments of 50 Nm at the beginning of the lift, irrespective of whether the burden was between or in front of the feet. During machine milking, a level difference between operator and cow of 0.70 m - 1.0 m significantly lowered the knee extending moments. To quantify the force magnitudes acting in the tibio-femoral and patello-femoral joints, a local biomechanical model of the knee was developed using a combination of cadaver knee dissections and lateral knee radiographs of healthy subjects. The moment arm of the knee extensor was significantly shorter for women than for men, which resulted in higher knee joint forces in women if the same moment was produced. A diagram for quantifying patellar forces was worked out. The force magnitudes given by the knee joint biomechanical model correlated well with experimentally forces measured by others. During the parallel squat in powerlifting, the maximum flexing knee load moment was estimated to 335-550 Nm when carrying a 382.5 kg burden and the in vivo force of a complete quadriceps tendon-muscle rupture to between 10,900 and 18,300 N. During isokinetic knee extension, the tibio-femoral compressive force reached peak magnitudes of 9 times body weight and the anteroposterior shear force was close to 1 body weight at knee angles straighter than 60 degrees, indicating that high forces stress the anterior cruciate ligament. A proximal resistance pad position decreased the shear force considerably, and this position is recommended in early

  5. [Studies of the neuromuscular system of the knee joint].

    PubMed

    Börnert, K; Dippold, A

    1990-02-01

    The paper analysis the therapeutic effects of isometric training and electromechanic therapy (EMT) of the quadriceps muscles on subjects. The effects of the training practised with the knee joint bent was to be compared with previous results of training with the knee joint stretched. 36 subjects were trained and the increase in strength was measured with the help of a strain gauge dynamometer. Again a marked superiority of the EMT over sole isometric training could be demonstrated. More over, the results showed that the increase of the isometric maximal strength following an EMT is not influenced by the position of the angle of the joint.

  6. Training-related changes in the EMG-moment relationship during isometric contractions: Further evidence of improved control of muscle activation in strength-trained men?

    PubMed

    Amarantini, David; Bru, Bertrand

    2015-08-01

    The possibility of using electromyography (EMG) to track muscle activity has raised the question of its relationship with the effort exerted by the muscles around the joints. However, the EMG-moment relationship is yet to be fully defined, and increasing knowledge of this topic could contribute to research in motor control and to the development of EMG-based algorithms and devices. With regards the training-related adaptations at the peripheral and central level, the present study investigated the effect of strength training on EMG-moment relationship. Our aim was to clarify its nature and gain further understanding of how morphological and neural factors may affect its form. The EMG-moment relationship was determined during knee flexion and extension isometric contractions performed by strength-trained male athletes and untrained male participants. The results showed that strength training induced linearity of the EMG-moment relationship concomitantly with enhanced maximum force production capacity and decreased co-activation of knee agonist-antagonist muscle pair. These results clarified discordant results regarding the linear or curved nature of the EMG-moment in isometric conditions and suggested that the remarkable linearity of the EMG-moment found in trained participants could indicate improved control of muscle activation.

  7. Monitoring muscle metabolic indexes by time-domain near-infrared spectroscopy during knee flex-extension induced by functional electrical stimulation

    NASA Astrophysics Data System (ADS)

    Ferrante, Simona; Contini, Davide; Spinelli, Lorenzo; Pedrocchi, Alessandra; Torricelli, Alessandro; Molteni, Franco; Ferrigno, Giancarlo; Cubeddu, Rinaldo

    2009-07-01

    A noninvasive methodology, combining functional electrical stimulation and time-domain near-infrared spectroscopy (TD-NIRS), is developed to verify whether stroke-altered muscular metabolism on postacute patients. Seven healthy subjects and nine postacute stroke patients undergo a protocol of knee flex-extension induced by quadricep electrical stimulation. During the protocol, TD-NIRS measurements are performed on both rectus femoris to investigate whether significant differences arise between able-bodied and stroke subjects and between patients' paretic and healthy legs. During baseline, metabolic parameters do not show any significant differences among subjects. During stimulation, paretic limbs produce a knee angle significantly lower than healthy legs. During recovery, patients' healthy limbs show a metabolic behavior correlated to able-bodied subjects. Instead, the correlation between the metabolic behavior of the paretic and able-bodied legs allows the definition of two patients' subgroups: one highly correlated (R>0.87) and the other uncorrelated (R<0.08). This grouping reflects the patient functional condition. The results obtained on the most impaired patients suggest that stroke does not produce any systemic consequences at the muscle, but the metabolic dysfunction seems to be local and unilateral. It is crucial to enlarge the sample size of the two subgroups before making these preliminary results a general finding.

  8. Comparison of elasticity of human tendon and aponeurosis in knee extensors and ankle plantar flexors in vivo.

    PubMed

    Kubo, Keitaro; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2005-05-01

    The purposes of this study were to compare the elasticity of tendon and aponeurosis in human knee extensors and ankle plantar flexors in vivo and to examine whether the maximal strain of tendon was correlated to that of aponeurosis. The elongation of tendon and aponeurosis during isometric knee extension (n = 23) and ankle plantar flexion (n = 22), respectively, were determined using a real-time ultrasonic apparatus, while the participants performed ramp isometric contractions up to voluntary maximum. To calculate the strain values from the measured elongation, we measured the respective length of tendon and aponeurosis. For the knee extensors, the maximal strain of aponeurosis (12.1 +/- 2.8 %) was significantly greater than that of the patella tendon (8.3 +/- 2.4 %), p < 0.001. On the contrary, the maximal strain of Achilles tendon (5.9 +/- 1.4 %) was significantly greater than that of aponeurosis in ankle plantar flexors (2.7 +/- 1.4 %), p < 0.001. Furthermore, for both knee extensors and ankle plantar flexors there was no significant correlation between maximal strain of tendon and aponeurosis. These results would be important for understanding the different roles of tendon and aponeurosis during human movements and for more accurate muscle modeling.

  9. Effects of Low-Impact Dance on Blood Biochemistry, Bone Mineral Density, the Joint Range of Motion of Lower Extremities, Knee Extension Torque, and Fall in Females.

    PubMed

    Wu, Hui Ying; Tu, Jui Hung; Hsu, Chin Hsing; Tsao, Te Hung

    2016-01-01

    The effect of low-impact dance on blood metabolites, the joint range of motion (ROM) of the lower extremities, knee extension torque, bone mass density (BMD), the number of falls, and the confidence to perform daily activities (Modified Falls Efficacy Scale [MFES]) was examined in older sedentary women (age: 59 ± 4 years) before and after a 16-week intervention. Results showed that the average score for the MFES, some parameters of blood chemistry, and joint ROM were significantly improved after low-impact intervention. In addition to improvements in blood lipids and body fat percentages, the increases shown in the parameters regarding the lower extremities may contribute to confidence in performing common daily activities in older women, although the number of falls did not significantly differ between the two groups during the 16-week period.

  10. The influence of familiarization sessions on the stability of ramp and ballistic isometric torque in older adults.

    PubMed

    Wallerstein, Lilian F; Barroso, Renato; Tricoli, Valmor; Mello, Marco T; Ugrinowitsch, Carlos

    2010-10-01

    Ramp isometric contractions determine peak torque (PT) and neuromuscular activation (NA), and ballistic contractions can be used to evaluate rate of torque development (RTD) and electrical mechanical delay (EMD). The purposes of this study were to assess the number of sessions required to stabilize ramp and ballistic PT and to compare PT and NA between contractions in older adults. Thirty-five older men and women (age 63.7 ± 3.7 yr, body mass 64.3 ± 10.7 kg, height 159.2 ± 6.6 cm) performed 4 sessions of unilateral ramp and ballistic isometric knee extension, 48 hr apart. PT significantly increased (main time effect p < .05) from the first to the third session, with no further improvements thereafter. There was a trend toward higher PT in ballistic than in ramp contractions. No difference between contraction types on EMG values was observed. Therefore, the authors suggest that 3 familiarization sessions be performed to correctly assess PT. In addition, PT, NA, RTD, and EMD can be assessed with ballistic contraction in older adults.

  11. Influence of aging on isometric muscle strength, fat-free mass and electromyographic signal power of the upper and lower limbs in women

    PubMed Central

    Amaral, Josária F.; Alvim, Felipe C.; Castro, Eliane A.; Doimo, Leonice A.; Silva, Marcus V.; Novo, José M.

    2014-01-01

    Background Aging is a multifactorial process that leads to changes in the quantity and quality of skeletal muscle and contributes to decreased levels of muscle strength. Objective This study sought to investigate whether the isometric muscle strength, fat-free mass (FFM) and power of the electromyographic (EMG) signal of the upper and lower limbs of women are similarly affected by aging. Method The sample consisted of 63 women, who were subdivided into three groups (young (YO) n=33, 24.7±3.5 years; middle age (MA) n=15, 58.6±4.2 years; and older adults (OA). n=15, 72.0±4.2 years). Isometric strength was recorded simultaneously with the capture of the electrical activity of the flexor muscles of the fingers and the vastus lateralis during handgrip and knee extension tests, respectively. FFM was assessed using dual-energy X-ray absorptiometry. Results The handgrip strength measurements were similar among groups (p=0.523), whereas the FFM of the upper limbs was lower in group OA compared to group YO (p=0.108). The RMSn values of the hand flexors were similar among groups (p=0.754). However, the strength of the knee extensors, the FFM of the lower limbs and the RMSn values of the vastus lateralis were lower in groups MA (p=0.014, p=0.006 and p=0.013, respectively) and OA (p=0.000, p=0.000 and p<0.000, respectively) compared to group YO. Conclusions The results of this study demonstrate that changes in isometric muscle strength in MLG and electromyographic activity of the lower limbs are more pronounced with the aging process of the upper limb. PMID:24676705

  12. Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men

    NASA Technical Reports Server (NTRS)

    Shaffer-Bailey, M.; Greenleaf, J. E.; Hutchinson, T. M.

    1996-01-01

    PURPOSE: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. METHODS: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degree.s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees.s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1+/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degree C) treatments. RESULTS: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54+/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml.6 h(-1)) was 28% greater (p < 0.05) than that of 975 +/- 139 ml.6 h(-1) with HDT. Muscular endurance (total work; maximal flexion-extension of the non-dominant knee at 180 degrees.s(-1) for 30 s) was not different between AC and the WI or HDT treatments. Shoulder-, knee-, and ankle-joint strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees.s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (delta = -6%, p < 0.05) with WI; and AC torques (180 degrees.s(-1), 260 +/- 19 Nm) decreased to 236 +/- 15 Nm (delta = -9%, p < 0.01) with HDT, and to 235 +/- 19 Nm (delta = -10%, p < 0.01) with WI. CONCLUSION: Thus, the total body hypohydration threshold level for shoulder- and ankle-joint strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees.s(-1) and lighter (180 degrees.s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after

  13. [Long-term results of proximal osteocartilaginous autografts in extensive cartilagenous destruction of the knee. Apropos of 5 cases].

    PubMed

    Maynou, C; Mestdagh, H; Beltrand, E; Petroff, E; Dubois, H

    1998-06-01

    Five patients with a large defect in the articular cartilage at the knee joint were treated by transplantation of an autogenic osteochondral fragment. The graft was harvested from the posterior portion of the ipsilateral femoral condyle in 4 cases of osteochondritis dissecans, and from the lateral third of the patella pedicled on the patellar ligament in one case of posttraumatic necrotic collapse of the lateral tibial plateau. One patient underwent concomitant high tibial osteotomy. Two months postoperatively bony union was achieved in all cases but in one case, the grafted articular cartilage did not survive after weight bearing because of an overlooked varus deformity. At the follow-up examination (8 to 20 years) all 5 patients were asymptomatic ; the range of flexion was somewhat restricted (120 degrees) ; roentgenogram revealed slight narrowing of the articular space or at least flattening of the grafted zone and subchondral osteosclerosis. At arthroscopic exploration, the grafted zones were recognizable from the surrounding cartilage, and histologic examination of their border revealed fibrocartilage and proliferating vessels; late gonarthrosis might ensue over time. Therefore the procedure should be performed only in large osteochondral defects where neither reattachment of a loose body, nor hemiarthroplasty, nor isolated osteotomy are suitable and before degenerative changes have developed. Morever any associated varus deformity requires concomitant correction by high tibial osteotomy to relieve stress from the graft.

  14. Evolution of knee kinematics three months after total knee replacement.

    PubMed

    Alice, Bonnefoy-Mazure; Stéphane, Armand; Yoshisama, Sagawa Junior; Pierre, Hoffmeyer; Domizio, Suvà; Hermes, Miozzari; Katia, Turcot

    2015-02-01

    In patients with debilitating knee osteoarthritis, total knee replacement is the most common surgical procedure. Numerous studies have demonstrated that knee kinematics one year after total knee replacement are still altered compared to the healthy joint. However, little is known regarding impairments and functional limitations of patients several months after total knee replacement. The aim of this study was to describe the evolution of the knee gait kinematic in patients with knee osteoarthritis before and three months after a total knee replacement. Ninety patients who were to undergo total knee replacement were included in this study. Twenty-three subjects were recruited as the control group. Three-dimensional gait analysis was performed before and three months after surgery. The spatio-temporal parameters and three-dimensional knee kinematics for the operated limb were evaluated during a comfortable gait and compared between groups (the before and after surgery groups and the control group). Three months after surgery, patients always walk with a slower gait velocity and lower knee flexion-extension movements compared to the control group. However, a degree of progress was observed in term of the stride and step length, gait velocity and knee alignment in the coronal plane. Our results suggest that the disability is still significant for most patients three months after total knee replacement. A better understand of the impairments and functional limitations following surgery would help clinicians design rehabilitation programs. Moreover, patients should be informed that rehabilitation after total knee replacement is a long process.

  15. Effects of weight lifting training combined with plyometric exercises on physical fitness, body composition, and knee extension velocity during kicking in football.

    PubMed

    Perez-Gomez, Jorge; Olmedillas, Hugo; Delgado-Guerra, Safira; Ara, Ignacio; Vicente-Rodriguez, German; Ortiz, Rafael Arteaga; Chavarren, Javier; Calbet, Jose A L

    2008-06-01

    The effects of a training program consisting of weight lifting combined with plyometric exercises on kicking performance, myosin heavy-chain composition (vastus lateralis), physical fitness, and body composition (using dual-energy X-ray absorptiometry (DXA)) was examined in 37 male physical education students divided randomly into a training group (TG: 16 subjects) and a control group (CG: 21 subjects). The TG followed 6 weeks of combined weight lifting and plyometric exercises. In all subjects, tests were performed to measure their maximal angular speed of the knee during in-step kicks on a stationary ball. Additional tests for muscle power (vertical jump), running speed (30 m running test), anaerobic capacity (Wingate and 300 m running tests), and aerobic power (20 m shuttle run tests) were also performed. Training resulted in muscle hypertrophy (+4.3%), increased peak angular velocity of the knee during kicking (+13.6%), increased percentage of myosin heavy-chain (MHC) type IIa (+8.4%), increased 1 repetition maximum (1 RM) of inclined leg press (ILP) (+61.4%), leg extension (LE) (+20.2%), leg curl (+15.9%), and half squat (HQ) (+45.1%), and enhanced performance in vertical jump (all p < or = 0.05). In contrast, MHC type I was reduced (-5.2%, p < or = 0.05) after training. In the control group, these variables remained unchanged. In conclusion, 6 weeks of strength training combining weight lifting and plyometric exercises results in significant improvement of kicking performance, as well as other physical capacities related to success in football (soccer).

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

    PubMed Central

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

    2001-01-01

    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 τ 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. PMID:11711581

  17. Dynamic Frequency Analyses of Lower Extremity Muscles during Sit-To-Stand Motion for the Patients with Knee Osteoarthritis

    PubMed Central

    Suzuki, Kentaro; Yagi, Masahide

    2016-01-01

    Objective Muscle activities during the sit-to-stand motion (STS) are characterized by coordinated movements between hip extensors and knee extensors. However, previous reports regarding the STS and lower extremity muscle activities have focused on some quantitative assessment, but little qualitative research. This study aimed to examine the muscle activities of the lower extremity both quantitatively and qualitatively. Methods Study participants included 13 patients with knee osteoarthritis (knee OA) and 11 age-matched asymptomatic controls. The task was STS from a chair with a height-adjustable seat. EMG activities were acquired using surface electromyogram. The root mean square signals normalized as a percentage of maximum voluntary isometric contraction values (RMS%MVC) and the mean power frequency (MPF) were calculated. Results During STS, knee OA patients had increased RMS%MVC of the vastus medialis and raised MPF of the rectus femoris before buttocks-off. Conclusion These findings suggest that STS of knee OA patients not only increased relative muscle activity of the vastus medialis, but also enlisted the rectus femoris in knee extension to improve muscle contraction force by activating more type II fibers to accomplish buttocks-off. PMID:26807578

  18. Assessing the accuracy of subject-specific, muscle-model parameters determined by optimizing to match isometric strength.

    PubMed

    DeSmitt, Holly J; Domire, Zachary J

    2016-12-01

    Biomechanical models are sensitive to the choice of model parameters. Therefore, determination of accurate subject specific model parameters is important. One approach to generate these parameters is to optimize the values such that the model output will match experimentally measured strength curves. This approach is attractive as it is inexpensive and should provide an excellent match to experimentally measured strength. However, given the problem of muscle redundancy, it is not clear that this approach generates accurate individual muscle forces. The purpose of this investigation is to evaluate this approach using simulated data to enable a direct comparison. It is hypothesized that the optimization approach will be able to recreate accurate muscle model parameters when information from measurable parameters is given. A model of isometric knee extension was developed to simulate a strength curve across a range of knee angles. In order to realistically recreate experimentally measured strength, random noise was added to the modeled strength. Parameters were solved for using a genetic search algorithm. When noise was added to the measurements the strength curve was reasonably recreated. However, the individual muscle model parameters and force curves were far less accurate. Based upon this examination, it is clear that very different sets of model parameters can recreate similar strength curves. Therefore, experimental variation in strength measurements has a significant influence on the results. Given the difficulty in accurately recreating individual muscle parameters, it may be more appropriate to perform simulations with lumped actuators representing similar muscles.

  19. Metabolically assessed muscle fibre recruitment in brief isometric contractions at different intensities.

    PubMed

    Beltman, J G M; de Haan, A; Haan, H; Gerrits, H L; van Mechelen, W; Sargeant, A J

    2004-08-01

    This study investigated the recruitment of type I, IIA and IIAX fibres after seven isometric contractions at 40, 70 and 100% maximal voluntary knee extension torque (MVC, 1 s on/1 s off). Biopsies of the vastus lateralis muscle were collected from seven subjects at rest and immediately post-exercise. Fibre fragments were dissected from the freeze-dried samples and characterized as type I, IIA and IIAX using mATPase staining. Phosphocreatine (PCr) and creatine (Cr) content were measured in the remaining part of characterized fibres. A decline in the ratio of PCr to Cr (PCr/Cr) was used as an indication of activation. The mean peak torques were, respectively, 39 (2), 72 (2) and 87 (6)% MVC. Cumulative distributions of type I and IIA fibres were significantly shifted to lower PCr/Cr ratios at all intensities (Kolmogorov-Smirnov test, P<0.05). The cumulative distribution of type IIAX fibres showed a significant leftward shift only at 87% MVC ( P<0.05). A hierarchical order of fibre activation with increasing intensity of exercise was found, with some indication of rate coding for type I and IIA fibres. Evidence for activation of type IIAX fibres was only found at 87% MVC.

  20. Ocular hemodynamics during isometric exercise.

    PubMed

    Kiss, B; Dallinger, S; Polak, K; Findl, O; Eichler, H G; Schmetterer, L

    2001-01-01

    The autoregulatory capacity of the human retina is well documented, but the pressure-flow relationship of the human choroid is still a matter of controversy. Recent data, using laser Doppler flowmetry to measure choroidal blood flow, indicate that the choroid has some autoregulatory potential, whereas most data using other techniques for the assessment of choroidal hemodynamics indicate that the choroidal pressure-flow curve is linear. We used a new laser interferometric technique to characterize choroidal blood flow during isometric exercise. Twenty healthy subjects performed squatting for 6 min during normocapnia and during inhalation of 5% CO2 and 95% air. Ocular fundus pulsation amplitude, flow velocities in the ophthalmic artery, intraocular pressure, and systemic hemodynamics were measured in 2-min intervals. To gain information on choroidal blood flow fundus pulsation amplitude was corrected for changes in flow pulsatility using data from the ophthalmic artery and for changes in pulse rate. Ocular perfusion pressure was calculated from mean arterial pressure and intraocular pressure. The ocular pressure-flow relationship was calculated by sorting data according to ascending ocular perfusion pressure values. In a pilot study in 6 healthy subjects comparable ocular pressure flow relationships were obtained when choroidal blood flow was assessed with the method described above and with laser Doppler flowmetry. In the main study isometric exercise caused a significant increase in mean arterial pressure (56%, P < 0.001), pulse rate (84%, P < 0.001), and intraocular pressure (37%, P 0.004), but decreased fundus pulsation amplitude (-36%, P < 0.001). Significant deviations from baseline choroidal blood flow were observed only at ocular perfusion pressures >69% during normocapnia and 70% during hypercapnia. Our data indicate that during isometric exercise the choroid has a high capacity to keep blood flow constant despite changes in perfusion pressure and that this

  1. Dynamic splinting for knee flexion contracture following total knee arthroplasty: a case report.

    PubMed

    Finger, Eric; Willis, F Buck

    2008-12-29

    Total Knee Arthroplasty operations are increasing in frequency, and knee flexion contracture is a common pathology, both pre-existing and post-operative. A 61-year-old male presented with knee flexion contracture following a total knee arthroplasty. Physical therapy alone did not fully reduce the contracture and dynamic splinting was then prescribed for daily low-load, prolonged-duration stretch. After 28 physical therapy sessions, the active range of motion improved from -20 degrees to -12 degrees (stiff knee still lacking full extension), and after eight additional weeks with nightly wear of dynamic splint, the patient regained full knee extension, (active extension improved from -12 degrees to 0 degrees ).

  2. Knee Bursitis

    MedlinePlus

    ... make a diagnosis of knee bursitis during a physical exam. Your doctor will inspect your knee by: Comparing the condition of both knees, particularly if only one is painful Gently pressing on different areas of your knee to detect warmth, swelling and the source of pain Carefully moving ...

  3. [Plea for accelerated rehabilitation after ligament plasty of the knee by a bone-patellar tendon-bone graft].

    PubMed

    Boileau, P; Rémi, M; Lemaire, M; Rousseau, P; Desnuelle, C; Argenson, C

    1999-09-01

    Knee rehabilitation after ACL repair with bone-tendon-bone graft is still controversial. While there was a tendency to protect the graft and the donor site in the eighties, actual tendency is to propose more aggressive, so called accelerated rehabilitation protocol. An extensive analysis of the literature shows that this accelerated rehabilitation is justified because of histologic, biomechanic, surgical and clinical arguments. This accelerated rehabilitation is based on seven reasons, at least: 1) the necrosis of the graft, initially observed in animals, does not seem to be as important in humans as demonstrated by histological studies after in vivo biopsies; 2) the use of solid bone-tendon-bone graft, whose resistance is maximum in the early post-operative period and is superior to the resistance of the ACL; 3) the more precise positioning (more "isometric") because of optic magnification allowed by arthroscopy; 4) the absence of graft impingement, routinely controlled, because of a more posterior tibial placement of the graft and the eventual notch-plasty; 5) the solid and confident fixation of the graft because of interference screws; 6) anterior knee pain are less important when early constraints are applied on the knee; 7) finally, undisciplined and demanding patients who refuse all protection for the graft and the donor site, have good and stable results regarding stability of the knees. Early constraints on the knee after bone-tendon-bone graft and interference fixation give better tolerance on the extension mechanism without compromising integrity of the graft and knee stability. Appropriate level of constraints on the ACL graft and the donor site guides the collagenic reorganisation process. Early restoration of normal hyperextension, decreased knee pain and maintenance of muscular trophicity, allowing patients to go back to sport at 4 months, are the most evident benefits of this accelerated rehabilitation. These considerations cannot be applied to the

  4. The use of the isometric squat as a measure of strength and explosiveness.

    PubMed

    Bazyler, Caleb D; Beckham, George K; Sato, Kimitake

    2015-05-01

    The isometric squat has been used to detect changes in kinetic variables as a result of training; however, controversy exists in its application to dynamic multijoint tasks. Thus, the purpose of this study was to further examine the relationship between isometric squat kinetic variables and isoinertial strength measures. Subjects (17 men, 1-repetition maximum [1RM]: 148.2 ± 23.4 kg) performed squats 2 d · wk(-1) for 12 weeks and were tested on 1RM squat, 1RM partial squat, and isometric squat at 90° and 120° of knee flexion. Test-retest reliability was very good for all isometric measures (intraclass correlation coefficients > 0.90); however, rate of force development 250 milliseconds at 90° and 120° seemed to have a higher systematic error (relative technical error of measurement = 8.12%, 9.44%). Pearson product-moment correlations indicated strong relationships between isometric peak force at 90° (IPF 90°) and 1RM squat (r = 0.86), and IPF 120° and 1RM partial squat (r = 0.79). Impulse 250 milliseconds (IMP) at 90° and 120° exhibited moderate to strong correlations with 1RM squat (r = 0.70, 0.58) and partial squat (r = 0.73, 0.62), respectively. Rate of force development at 90° and 120° exhibited weak to moderate correlations with 1RM squat (r = 0.55, 0.43) and partial squat (r = 0.32, 0.42), respectively. These findings demonstrate a degree of joint angle specificity to dynamic tasks for rapid and peak isometric force production. In conclusion, an isometric squat performed at 90° and 120° is a reliable testing measure that can provide a strong indication of changes in strength and explosiveness during training.

  5. Kinesiologic measurements of functional performance before and after geometric total knee replacemtn: one-year follow-up of twenty cases.

    PubMed

    Collopy, M C; Murray, M P; Gardner, G M; DiUlio, R A; Gore, D R

    1977-01-01

    Kinesiologic measurements were made in patients with severe arthritis before and after geometric total knee replacements to evaluate the nature, rate and extent of change in their functional ability. Preoperatively, patients with rheumatoid arthritis functioned at lower levels than patients with osteoarthritis. Most patients with rheumatoid arthritis improved steadily after surgery, while progress of those with osteoarthritis was often irregular. The group with rheumatoid arthritis improved more than those with osteoarthritis, but they did not generally reach the functional level attained by the patients with osteoarthritis, and neither group reached the lower limits of normal variability 1 year postoperatively. On the average, both groups gained knee extensions, lost knee flexion, and gained isometric knee flexor muscle strength postoperatively. Every patient with osteoarthritis lost extensor muscle strength 1 year after surgery, while most with rheumatoid arthritis gained. During quiet standing, most patients had straighter knees postoperatively and bore a greater percent of body weight on the operated limb. Patients with rheumatoid arthritis improved more than patients with osteoarthritis in the type and amount of force applied to canes and crutches. Most patients walked faster postoperatively, took longer and more rapid steps, improved the pattern of knee motion used, and had smoother forward, lateral and vertical head motion.

  6. Tibia valga morphology in osteoarthritic knees: importance of preoperative full limb radiographs in total knee arthroplasty.

    PubMed

    Alghamdi, Ahmed; Rahmé, Michel; Lavigne, Martin; Massé, Vincent; Vendittoli, Pascal-André

    2014-08-01

    Osteoarthritis of the knee is associated with deformities of the lower limb. Tibia valga is a contributing factor to lower limb alignment in valgus knees. We evaluated 97 valgus knees and 100 varus knees. Long-leg films were taken in weight bearing with both knees in full extension. For valgus knees, 52 knees (53%) had a tibia valga deformity. Average tibia valgus deformation was 5.0°. For varus knees, there was only 1 case of tibia valga (1%), with a deformation of 2.5°. The aim of this study was to assess the prevalence of primary tibia valga in valgus and varus knees and understand how it affects our approach to total knee arthroplasty (TKA). We recommend having full-leg length films when planning for TKA in valgus knees.

  7. Neuromuscular fatigue following isometric contractions with similar torque time integral.

    PubMed

    Rozand, V; Cattagni, T; Theurel, J; Martin, A; Lepers, R

    2015-01-01

    Torque time integral (TTI) is the combination of intensity and duration of a contraction. The aim of this study was to compare neuromuscular alterations following different isometric sub-maximal contractions of the knee extensor muscles but with similar TTI. Sixteen participants performed 3 sustained contractions at different intensities (25%, 50%, and 75% of Maximal Voluntary Contraction (MVC) torque) with different durations (68.5±33.4 s, 35.1±16.8 s and 24.8±12.9 s, respectively) but similar TTI value. MVC torque, maximal voluntary activation level (VAL), M-wave characteristics and potentiated doublet amplitude were assessed before and immediately after the sustained contractions. EMG activity of the vastus lateralis (VL) and -rectus femoris (RF) muscles was recorded during the sustained contractions. MVC torque reduction was similar in the 3 conditions after the exercise (-23.4±2.7%). VAL decreased significantly in a similar extent (-3.1±1.3%) after the 3 sustained contractions. Potentiated doublet amplitude was similarly reduced in the 3 conditions (-19.7±1.5%), but VL and RF M-wave amplitudes remained unchanged. EMG activity of VL and RF muscles increased in the same extent during the 3 contractions (VL: 54.5±40.4%; RF: 53.1±48.7%). These results suggest that central and peripheral alterations accounting for muscle fatigue are similar following isometric contractions with similar TTI. TTI should be considered in the exploration of muscle fatigue during sustained isometric contractions.

  8. Oxygen cost of dynamic or isometric exercise relative to recruited muscle mass

    PubMed Central

    Elder, Christopher P; Mahoney, Edward T; Black, Christopher D; Slade, Jill M; Dudley, Gary A

    2006-01-01

    Background Oxygen cost of different muscle actions may be influenced by different recruitment and rate coding strategies. The purpose of this study was to account for these strategies by comparing the oxygen cost of dynamic and isometric muscle actions relative to the muscle mass recruited via surface electrical stimulation of the knee extensors. Methods Comparisons of whole body pulmonary Δ V˙ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuWGwbGvgaGaaaaa@2DEA@O2 were made in seven young healthy adults (1 female) during 3 minutes of dynamic or isometric knee extensions, both induced by surface electrical stimulation. Recruited mass was quantified in T2 weighted spin echo magnetic resonance images. Results The Δ V˙ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuWGwbGvgaGaaaaa@2DEA@O2 for dynamic muscle actions, 242 ± 128 ml • min-1 (mean ± SD) was greater (p = 0.003) than that for isometric actions, 143 ± 99 ml • min-1. Recruited muscle mass was also greater (p = 0.004) for dynamic exercise, 0.716 ± 282 versus 0.483 ± 0.139 kg. The rate of oxygen consumption per unit of recruited muscle (V˙O2RM MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacuqGwbGvgaGaaiabb+eapnaaBaaaleaacqaIYaGmdaahaaadbeqaaiabbkfasjabb2eanbaaaSqabaaaaa@32B0@) was similar in dynamic and isometric exercise (346 ± 162 versus 307 ± 198 ml • kg-1 • min-1; p = 0.352), but the V˙O2RM MathType@MTEF@5

  9. Serratus Anterior and Lower Trapezius Muscle Activities During Multi-Joint Isotonic Scapular Exercises and Isometric Contractions.

    PubMed

    Tsuruike, Masaaki; Ellenbecker, Todd

    2014-11-14

    Context :  Proper scapular function during humeral elevation, such as upward rotation, external rotation, and posterior tilting of the scapula, is necessary to prevent shoulder injury. However, the appropriate intensity of rehabilitation exercise for the periscapular muscles has yet to be clarified. Objective :  To identify the serratus anterior, lower trapezius, infraspinatus, and posterior deltoid muscle activities during 2 free-motion exercises using 3 intensities and to compare these muscle activities with isometric contractions during quadruped shoulder flexion and external rotation and abduction of the glenohumeral joint. Design :  Cross-sectional study. Setting :  Health Science Laboratory. Patients or Other Participants :  A total of 16 uninjured, healthy, active, male college students (age = 19.5 ± 1.2 years, height = 173.1 ± 6.5 cm, weight = 68.8 ± 6.6 kg). Main Outcome Measure(s) :  Mean electromyographic activity normalized by the maximal voluntary isometric contraction was analyzed across 3 intensities and 5 exercises. Intraclass correlation coefficients were calculated for electromyographic activity of the 4 muscles in each free-motion exercise. Results :  Significant interactions in electromyographic activity were observed between intensities and exercises (P < .05). The quadruped shoulder-flexion exercise activated all 4 muscles compared with other exercises. Also, the modified robbery free-motion exercise activated the serratus anterior, lower trapezius, and infraspinatus compared with the lawn-mower free-motion exercise. However, neither exercise showed a difference in posterior deltoid electromyographic activity. Conclusions :  Three intensities exposed the nature of the periscapular muscle activities across the different exercises. The free-motion exercise in periscapular muscle rehabilitation may not modify serratus anterior, lower trapezius, and infraspinatus muscle activities unless knee-joint extension is limited.

  10. Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Proposed orthotic knee joint locks and unlocks automatically, at any position within range of bend angles, without manual intervention by wearer. Includes tang and clevis, locks whenever wearer transfers weight to knee and unlocks when weight removed. Locking occurs at any angle between 45 degrees knee bend and full extension.

  11. Knee pain, knee injury, knee osteoarthritis & work.

    PubMed

    Dulay, Gurdeep S; Cooper, C; Dennison, E M

    2015-06-01

    Symptomatic knee osteoarthritis (OA) can be viewed as the end result of a molecular cascade which ensues after certain triggers occur and ultimately results in irreversible damage to the articular cartilage. The clinical phenotype that knee OA can produce is variable and often difficult to accurately predict. This is further complicated by the often poor relationship between radiographic OA and knee pain. As a consequence, it can be difficult to compare studies that use different definitions of OA. However, the literature suggests that while there are multiple causes of knee OA, two have attracted particular attention over recent years; occupation related knee OA and OA subsequent to previous knee injury. The evidence of a relationship, and the strength of this association, is discussed in this chapter.

  12. Knee injuries and Alpine skiing. Treatment and rehabilitation.

    PubMed

    Paletta, G A; Warren, R F

    1994-06-01

    central third of the patella tendon using a bone-tendon-bone autograft. Postoperative rehabilitation employs a functional staged approach, requiring vigilant supervision by the surgeon. Isolated posterior cruciate ligament (PCL) injury is rare in skiing, constituting less than 1% of all knee injuries in most series. Careful physical examination must be employed to rule out associated arcuate ligament complex injury and more complex patterns of instability. Most isolated PCL injuries are treated nonoperatively with a programme of initial immobilisation in extension, ice, protected weight-bearing, early range-of-motion exercises and progressive isometric strengthening.(ABSTRACT TRUNCATED AT 400 WORDS)

  13. Dissociation between the time courses of femoral artery blood flow and pulmonary VO2 during repeated bouts of heavy knee extension exercise in humans.

    PubMed

    Fukuba, Yoshiyuki; Ohe, Yukie; Miura, Akira; Kitano, Asami; Endo, Masako; Sato, Hironori; Miyachi, Motohiko; Koga, Shunsaku; Fukuda, Osamu

    2004-05-01

    It has frequently been demonstrated that prior heavy cycling exercise facilitates pulmonary O(2) kinetics at the onset of subsequent heavy exercise. This might be due to improved muscle perfusion via acidosis-induced vasodilating effects. However, it is difficult to measure the blood flow (BF) to the working muscles (via the femoral artery) during cycling exercise. We therefore selected supine knee extension (KE) exercise as an alternative, and investigated whether the faster O(2) kinetics in the 2nd bout was matched by proportionally faster BF kinetics to the exercising muscle. Nine healthy subjects (aged 21-44 years) volunteered to participate in this study. The protocol consisted of two consecutive 6-min KE exercise bouts in a supine position (work rate: 70-75% of peak power) separated by a 6-min baseline rest (EX1 to EX2). During the protocol, a pulsed Doppler ultrasound technique was utilized to continuously measure the BF in the right femoral artery. The protocol was repeated at least 6 times to characterize the precise kinetics. In agreement with previous studies using cycling exercise, the O(2) kinetics in the 2nd bout were facilitated compared with that in the 1st bout [mean +/-s.d. of the 'effective' time constant (tau): EX1, 68.6 +/- 15.9, versus EX2, 58.0 +/- 14.4 s. Phase II-tau: EX1, 48.7 +/- 9.0, versus EX2, 41.2 +/- 13.3 s. Empirical index of the slow component (Delta O(2(6-3))): EX1, 78 +/- 44, versus EX2, 57 +/- 36 ml min(-1) (P < 0.05)]. However, no substantial difference was observed for the facilitation of the femoral artery BF response to the 1st and 2nd exercise bouts [i.e. the 'effective'tau of the femoral artery BF: EX1, 40.8 +/- 16.9, versus EX2, 39.0 +/- 17.1 s (P > 0.05)]. It was concluded that the faster pulmonary O(2) kinetics during heavy KE exercise following prior heavy exercise was not associated with a similar modulation in the BF to the working muscles.

  14. Nonuniform Weakness in the Paretic Knee and Compensatory Strength Gains in the Nonparetic Knee Occurs after Stroke

    PubMed Central

    Lomaglio, Melanie J.; Eng, Janice J.

    2015-01-01

    Background This study was designed to quantify torque production at different joint angles in the paretic and non-paretic knee joints of individuals with stroke. Methods Extension and flexion torques were measured at 6 angles of the knee joint and normalized to peak torque in 19 subjects with stroke and 19 controls. Results Paretic knee extension torque was lower than controls when the knee was positioned near extension. In contrast, nonparetic knee extension and flexion torques were higher than controls when the knee was positioned near full flexion. Conclusions The paretic knee extensors demonstrated exaggerated weakness at short muscle lengths and the nonparetic knee extensors and flexors demonstrated selective strength gains. Clinicians should therefore consider paretic knee extensor strengthening near full extension and promote symmetrical use of the legs to prevent compensatory overuse of the non-paretic leg. PMID:18946213

  15. [Physical activity for knee osteoarthritis.

    PubMed

    Nagao, Masashi; Ishijima, Muneaki; Kaneko, Haruka; Takazawa, Yuji; Ikeda, Hiroshi; Kaneko, Kazuo

    Elder populations have been increasing in Japan and estimated 24 million people have knee osteoarthritis(OA). Recently, people have diverse sociological background and demand for participating sports has been growing. People may participate sports to prevent some diseases such as locomotive syndrome. According to the recent studies, excessive high impact sports increase the risk of OA, while daily life exercise decrease the risk. Epidemiological approach demonstrated that reduced knee extension muscle strength increases the risk of OA. We reviewed and discussed the recent topics including efficacy of physical therapy for knee OA and how much sports activities could be beneficial after knee surgery.

  16. Custom Knee Device for Knee Contractures After Internal Femoral Lengthening.

    PubMed

    Bhave, Anil; Shabtai, Lior; Ong, Peck-Hoon; Standard, Shawn C; Paley, Dror; Herzenberg, John E

    2015-07-01

    The development of knee flexion contractures is among the most common problems and complications associated with lengthening the femur with an internal device or external fixator. Conservative treatment strategies include physical therapy, serial casting, and low-load prolonged stretching with commercially available splinting systems. The authors developed an individually molded, low-cost custom knee device with polyester synthetic conformable casting material to treat knee flexion contractures. The goal of this study was to evaluate the results of treatment with a custom knee device and specialized physical therapy in patients who had knee flexion contracture during femoral lengthening with an intramedullary lengthening femoral nail. This retrospective study included 23 patients (27 limbs) who underwent femoral lengthening with an internal device for the treatment of limb length discrepancy. All patients had a knee flexion contracture raging from 10° to 90° during the lengthening process and were treated with a custom knee device and specialized physical therapy. The average flexion contracture before treatment was 36°. The mean amount of lengthening was 5.4 cm. After an average of 3.8 weeks of use of the custom knee device, only 2 of 27 limbs (7.5%) had not achieved complete resolution of the flexion contracture. The average final extension was 1.4°. Only 7 of 27 limbs (26%) required additional soft tissue release. The custom knee device is an inexpensive and effective method for treating knee flexion contracture after lengthening with an internal device.

  17. Model-Based Estimation of Knee Stiffness

    PubMed Central

    Pfeifer, Serge; Vallery, Heike; Hardegger, Michael; Riener, Robert; Perreault, Eric J.

    2013-01-01

    During natural locomotion, the stiffness of the human knee is modulated continuously and subconsciously according to the demands of activity and terrain. Given modern actuator technology, powered transfemoral prostheses could theoretically provide a similar degree of sophistication and function. However, experimentally quantifying knee stiffness modulation during natural gait is challenging. Alternatively, joint stiffness could be estimated in a less disruptive manner using electromyography (EMG) combined with kinetic and kinematic measurements to estimate muscle force, together with models that relate muscle force to stiffness. Here we present the first step in that process, where we develop such an approach and evaluate it in isometric conditions, where experimental measurements are more feasible. Our EMG-guided modeling approach allows us to consider conditions with antagonistic muscle activation, a phenomenon commonly observed in physiological gait. Our validation shows that model-based estimates of knee joint stiffness coincide well with experimental data obtained using conventional perturbation techniques. We conclude that knee stiffness can be accurately estimated in isometric conditions without applying perturbations, which presents an important step towards our ultimate goal of quantifying knee stiffness during gait. PMID:22801482

  18. RELIABILITY AND VALIDITY OF A MODIFIED ISOMETRIC DYNAMOMETER IN THE ASSESSMENT OF MUSCULAR PERFORMANCE IN INDIVIDUALS WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

    PubMed Central

    de Vasconcelos, Rodrigo Antunes; Bevilaqua-Grossi, Débora; Shimano, Antonio Carlos; Paccola, Cleber Jansen; Salvini, Tânia Fátima; Prado, Christiane Lanatovits; Junior, Wilson A. Mello

    2015-01-01

    Objectives: The aim of this study was to evaluate the reliability and validity of a modified isometric dynamometer (MID) in performance deficits of the knee extensor and flexor muscles in normal individuals and in those with ACL reconstructions. Methods: Sixty male subjects were invited to participate of the study, being divided into three groups with 20 subjects each: control group (GC), group of individuals with ACL reconstruction with patellar tendon graft (GTP, and group of individuals with ACL reconstruction with hamstrings graft (GTF). All individuals performed isometric tests in the MID, muscular strength deficits collected were subsequently compared to the tests performed on the Biodex System 3 operating in the isometric and isokinetic mode at speeds of 60°/s and 180o/s. Intraclass ICC correlation calculations were done in order to assess MID reliability, specificity, sensitivity and Kappa's consistency coefficient calculations, respectively, for assessing the MID's validity in detecting muscular deficits and intra- and intergroup comparisons when performing the four strength tests using the ANOVA method. Results: The modified isometric dynamometer (MID) showed excellent reliability and good validity in the assessment of the performance of the knee extensor and flexor muscles groups. In the comparison between groups, the GTP showed significantly greater deficits as compared to the GTF and GC groups. Conclusion: Isometric dynamometers connected to mechanotherapy equipments could be an alternative option to collect data concerning performance deficits of the extensor and flexor muscles groups of the knee in subjects with ACL reconstruction. PMID:27004175

  19. Time course of neuromuscular adaptations to knee extensor eccentric training.

    PubMed

    Baroni, B M; Rodrigues, R; Franke, R A; Geremia, J M; Rassier, D E; Vaz, M A

    2013-10-01

    This study investigated the chronology of neural and morphological adaptations to knee extensor eccentric training and their contribution to strength gains in isometric, concentric and eccentric muscle actions. 20 male healthy subjects performed a 12-week eccentric training program on an isokinetic dynamometer, and neuromuscular evaluations of knee extensors were performed every 4 weeks. After 12 training weeks, significant increases were observed for: isometric (24%), concentric (15%) and eccentric (29%) torques; isometric (29%) and eccentric (33%) electromyographic activity; muscle thickness (10%) and anatomical cross-sectional area (19%). Eccentric and isometric torques increased progressively until the end of the program. Concentric torque and muscle mass parameters increased until the eighth training week, but did not change from this point to the twelfth training week. Eccentric and isometric activation increased at 4 and 8 training weeks, respectively, while no change was found in concentric activation. These results suggest that: 1) the relative increment in concentric strength was minor and does not relate to neural effects; 2) eccentric and isometric strength gains up to 8 training weeks are explained by the increased neural activation and muscle mass, whereas the increments in the last 4 training weeks seem to be associated with other mechanisms.

  20. Differences in proprioception, muscle force control and comfort between conventional and new-generation knee and ankle orthoses.

    PubMed

    Marchini, A; Lauermann, S P; Minetto, M A; Massazza, G; Maffiuletti, N A

    2014-06-01

    The aim of this study was to compare muscle force control and proprioception between conventional and new-generation experimental orthoses. Sixteen healthy subjects participated in a single-blind controlled trial in which two different types of orthosis were applied to the dominant knee or ankle, while the following variables were evaluated: muscle force control (accuracy), joint position sense, kinesthesia, static balance as well as subjective outcomes. The use of experimental orthoses resulted in better force accuracy during isometric knee extensions compared to conventional orthoses (P=0.005). Moreover, the use of experimental orthoses resulted in better force accuracy during concentric (P=0.010) and eccentric (P=0.014) ankle plantar flexions and better knee joint kinesthesia in the flexed position (P=0.004) compared to conventional orthoses. Subjective comfort (P<0.001) and preference scores were higher with experimental orthoses compared to conventional ones. In conclusion, orthosis type affected static and dynamic muscle force control, kinesthesia, and perceived comfort in healthy subjects. New-generation experimental knee and ankle orthoses may thus be recommended for prophylactic joint bracing during physical activity and to improve the compliance for orthosis use, particularly in patients who require long-term bracing.

  1. Methodology to Customize Maximal Isometric Forces for Hill-Type Muscle Models.

    PubMed

    Dal Maso, Fabien; Begon, Mickaël; Raison, Maxime

    2017-02-01

    One approach to increasing the confidence of muscle force estimation via musculoskeletal models is to minimize the root mean square error (RMSE) between joint torques estimated from electromyographic-driven musculoskeletal models and those computed using inverse dynamics. We propose a method that reduces RMSE by selecting subsets of combinations of maximal voluntary isometric contraction (MVIC) trials that minimize RMSE. Twelve participants performed 3 elbow MVIC in flexion and in extension. An upper-limb electromyographic-driven musculoskeletal model was created to optimize maximum muscle stress and estimate the maximal isometric force of the biceps brachii, brachialis, brachioradialis, and triceps brachii. Maximal isometric forces were computed from all possible combinations of flexion-extension trials. The combinations producing the smallest RMSE significantly reduced the normalized RMSE to 7.4% compared with the combination containing all trials (9.0%). Maximal isometric forces ranged between 114-806 N, 64-409 N, 236-1511 N, and 556-3434 N for the brachii, brachialis, brachioradialis, and triceps brachii, respectively. These large variations suggest that customization is required to reduce the difference between models and actual participants' maximal isometric force. While the smallest previously reported RMSE was 10.3%, the proposed method reduced the RMSE to 7.4%, which may increase the confidence of muscle force estimation.

  2. Radiological analysis on femoral tunnel positioning between isometric and anatomical reconstructions of the anterior cruciate ligament☆☆☆

    PubMed Central

    Vieira, Rodrigo Barreiros; de Pinho Tavares, Leonardo Augusto; Pace Lasmar, Rodrigo Campos; da Cunha, Fernando Amaral; de Melo Lisboa, Lucas Araujo

    2014-01-01

    Objective the aim of this study was to radiologically evaluate the femoral tunnel position in anterior cruciate ligament (ACL) reconstructions using the isometric and anatomical techniques. Methods a prospective analytical study was conducted on patients undergoing ACL reconstruction by means of the isometric and anatomical techniques, using grafts from the knee flexor tendons or patellar tendon. Twenty-eight patients were recruited during the immediate postoperative period, at the knee surgery outpatient clinic of FCMMG-HUSJ. Radiographs of the operated knee were produced in anteroposterior (AP) view with the patient standing on both feet and in lateral view with 30° of flexion. The lines were traced out and the distances and angles were measured on the lateral radiograph to evaluate the sagittal plane. The distance from the center of the screw to the posterior cortical bone of the lateral condyle was measured and divided by the Blumensaat line. In relation to the height of the screw, the distance from the center of the screw to the joint surface of the lateral condyle of the knee was measured. On the AP radiograph, evaluating the coronal plane, the angle between the anatomical axis of the femur and a line traced at the center of the screw was measured. Results with regard to the p measurement (posteriorization of the interference screw), the tests showed that the p-value (0.4213) was greater than the significance level used (0.05); the null hypothesis was not rejected and it could be stated that there was no statistically significant difference between the anatomical and isometric techniques. With regard to the H measurement (height of the screw in relation to the lower cortical bone of the knee), the p-value observed (0.0006) was less than the significance level used (0.05); the null hypothesis was rejected and it could be stated that there was a statistically significant difference between the anatomical and isometric techniques. It can be concluded that the

  3. Alpine Skiing With total knee ArthroPlasty (ASWAP): muscular adaptations.

    PubMed

    Rieder, F; Kösters, A; Wiesinger, H-P; Dorn, U; Hofstaedter, T; Fink, C; Seynnes, O R; Müller, E

    2015-08-01

    This study investigated the effectiveness of recreational skiing as an intervention to improve quadriceps muscle architecture, strength, and antagonistic co-activation in patients with unilateral total knee arthroplasty (TKA). Hence, patients with TKA were assigned to either an intervention group (IG) or control group (CG). The IG completed a 12-week guided skiing program whereas the CG was instructed not to change their daily routines for the same period and was not allowed to ski. Before, after the intervention/after an 8-week retention period m. rectus femoris (RF) cross-sectional area (CSA), m. vastus lateralis muscle thickness, fascicle length, and pennation angle were measured with ultrasonography, while isometric (90° knee angle) knee extension, flexion torque and m. biceps femoris co-activation were assessed on an isokinetic dynamometer in 26 patients. There were significant and stable increases in RF CSA for the operated (10%; P < 0.05) and non-operated leg (12%; P < 0.01) after the training period in the IG whereas no changes were observed for the CG (all P > 0.05). There were no significant effects for other parameters (all P > 0.05). Overall, the skiing intervention was successful in increasing muscle mass in TKA older patients.

  4. The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve

    PubMed Central

    Corbi, Francisco; Fuentes, Juan Pedro; Fernández-Fernández, Jaime

    2016-01-01

    Abstract The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg) were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation). Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p < 0.05). Low to moderate correlations were also found between serve velocity and wrist, elbow and shoulder flexion – extension, leg and back extension and shoulder external rotation (r = 0.36 – 0.53; p = 0.377 – 0.054). Bivariate and multivariate models for predicting serve velocity were developed, with shoulder flexion and internal rotation explaining 55% of the variance in serve velocity (r = 0.74; p < 0.001). The maximum isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion. PMID:28149411

  5. The Relationship Between Maximum Isometric Strength and Ball Velocity in the Tennis Serve.

    PubMed

    Baiget, Ernest; Corbi, Francisco; Fuentes, Juan Pedro; Fernández-Fernández, Jaime

    2016-12-01

    The aims of this study were to analyze the relationship between maximum isometric strength levels in different upper and lower limb joints and serve velocity in competitive tennis players as well as to develop a prediction model based on this information. Twelve male competitive tennis players (mean ± SD; age: 17.2 ± 1.0 years; body height: 180.1 ± 6.2 cm; body mass: 71.9 ± 5.6 kg) were tested using maximum isometric strength levels (i.e., wrist, elbow and shoulder flexion and extension; leg and back extension; shoulder external and internal rotation). Serve velocity was measured using a radar gun. Results showed a strong positive relationship between serve velocity and shoulder internal rotation (r = 0.67; p < 0.05). Low to moderate correlations were also found between serve velocity and wrist, elbow and shoulder flexion - extension, leg and back extension and shoulder external rotation (r = 0.36 - 0.53; p = 0.377 - 0.054). Bivariate and multivariate models for predicting serve velocity were developed, with shoulder flexion and internal rotation explaining 55% of the variance in serve velocity (r = 0.74; p < 0.001). The maximum isometric strength level in shoulder internal rotation was strongly related to serve velocity, and a large part of the variability in serve velocity was explained by the maximum isometric strength levels in shoulder internal rotation and shoulder flexion.

  6. Jumper's Knee (Patellar Tendonitis)

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Jumper's Knee KidsHealth > For Teens > Jumper's Knee A A A ... continued damage to the knee. How Does the Knee Work? To understand how jumper's knee happens, it ...

  7. Knee arthroscopy - series (image)

    MedlinePlus

    ... knee problems such as: a torn knee disc (meniscus) a damaged knee bone (patella) a damaged ligament ... surgeon can see the ligaments, the knee disc (meniscus), the knee bone (patella), the lining of the ...

  8. Prediction of three dimensional maximum isometric neck strength.

    PubMed

    Fice, Jason B; Siegmund, Gunter P; Blouin, Jean-Sébastien

    2014-09-01

    We measured maximum isometric neck strength under combinations of flexion/extension, lateral bending and axial rotation to determine whether neck strength in three dimensions (3D) can be predicted from principal axes strength. This would allow biomechanical modelers to validate their neck models across many directions using only principal axis strength data. Maximum isometric neck moments were measured in 9 male volunteers (29±9 years) for 17 directions. The 3D moments were normalized by the principal axis moments, and compared to unity for all directions tested. Finally, each subject's maximum principal axis moments were used to predict their resultant moment in the off-axis directions. Maximum moments were 30±6 N m in flexion, 32±9 N m in lateral bending, 51±11 N m in extension, and 13±5 N m in axial rotation. The normalized 3D moments were not significantly different from unity (95% confidence interval contained one), except for three directions that combined ipsilateral axial rotation and lateral bending; in these directions the normalized moments exceeded one. Predicted resultant moments compared well to the actual measured values (r2=0.88). Despite exceeding unity, the normalized moments were consistent across subjects to allow prediction of maximum 3D neck strength using principal axes neck strength.

  9. Determinants of skin sympathetic nerve responses to isometric exercise.

    PubMed

    Wilson, Thad E; Dyckman, Damian J; Ray, Chester A

    2006-03-01

    Exercise-induced increases in skin sympathetic nerve activity (SSNA) are similar between isometric handgrip (IHG) and leg extension (IKE) performed at 30% of maximal voluntary contraction (MVC). However, the precise effect of exercise intensity and level of fatigue on this relationship is unclear. This study tested the following hypotheses: 1) exercise intensity and fatigue level would not affect the magnitude of exercise-induced increase in SSNA between IHG and IKE, and 2) altering IHG muscle mass would also not affect the magnitude of exercise-induced increase in SSNA. In protocol 1, SSNA (peroneal microneurography) was measured during baseline and during the initial and last 30 s of isometric exercise to volitional fatigue in 12 subjects who randomly performed IHG and IKE bouts at 15, 30, and 45% MVC. In protocol 2, SSNA was measured in eight subjects who performed one-arm IHG at 30% MVC with the addition of IHG of the contralateral arm in 10-s intervals for 1 min. Exercise intensity significantly increased SSNA responses during the first 30 s of IHG (34+/-13, 70+/-11, and 92+/-13% change from baseline) and IKE (30+/-17, 69+/-12, and 76+/-13% change from baseline) for 15, 30, and 45% MVC. During the last 30 s of exercise to volitional fatigue, there were no significant differences in SSNA between exercise intensities or limb. SSNA did not significantly change between one-arm and two-arm IHG. Combined, these data indicate that exercise-induced increases in SSNA are intensity dependent in the initial portion of isometric exercise, but these differences are eliminated with the development of fatigue. Moreover, the magnitude of exercise-induced increase in SSNA responses is not dependent on either muscle mass involved or exercising limb.

  10. Quadriceps Inhibition After Repetitive Lumbar Extension Exercise in Persons With a History of Low Back Pain

    PubMed Central

    Hart, Joseph M; Fritz, Julie M; Kerrigan, D. Casey; Saliba, Ethan N; Gansneder, Bruce M; Ingersoll, Christopher D

    2006-01-01

    Context: A neuromuscular relationship exists between the lumbar extensor and quadriceps muscles during fatiguing exercise. However, this relationship may be different for persons with low back pain (LBP). Objective: To compare quadriceps inhibition after isometric, fatiguing lumbar extension exercise between persons with a history of LBP and control subjects. Design: A 2 × 3 factorial, repeated-measures, time-series design with independent variables of group (persons with a history of LBP, controls) and time (baseline, postexercise set 1, postexercise set 2). Setting: University research laboratory. Patients or Other Participants: Twenty-five subjects with a history of LBP were matched by sex, height, and mass to 25 healthy control subjects. Intervention(s): Electromyography median frequency indexed lumbar paraspinal muscular fatigue while subjects performed 2 sets of isometric lumbar extension exercise. Subjects exercised until a 15% downward shift in median frequency for the first set and a 25% shift for the second set were demonstrated. Main Outcome Measure(s): Knee extension force was measured while subjects performed an isometric maximal quadriceps contraction. During this maximal effort, a percutaneous electric stimulus was applied to the quadriceps, causing a transient, supramaximal increase in force output. We used the ratio between the 2 forces to estimate quadriceps inhibition. Quadriceps electromyographic activity was recorded during the maximal contractions to compare median frequencies over time. Results: Both groups exhibited significantly increased quadriceps inhibition after the first (12.6% ± 10.0%, P < .001) and second (15.2% ± 9.7%, P < .001) exercise sets compared with baseline (9.6% ± 9.3%). However, quadriceps inhibition was not different between groups. Conclusions: Persons with a history of LBP do not appear to be any more or less vulnerable to quadriceps inhibition after fatiguing lumbar extension exercise. PMID:17043693

  11. Runner's Knee

    MedlinePlus

    ... name just two. It's the most common overuse injury among runners, but it can also strike other athletes who do activities that require a lot of knee bending, such as biking, jumping, or skiing. Runner's knee happens when the kneecap (patella) tracks incorrectly over a ...

  12. Low-intensity eccentric contractions attenuate muscle damage induced by subsequent maximal eccentric exercise of the knee extensors in the elderly.

    PubMed

    Chen, Trevor C; Tseng, Wei-Chin; Huang, Guan-Ling; Chen, Hsin-Lian; Tseng, Kou-Wei; Nosaka, Kazunori

    2013-04-01

    This study investigated whether low-intensity eccentric contractions of the knee extensors would attenuate the magnitude of muscle damage induced by maximal eccentric exercise of the same muscle performed 7 days later using elderly individuals. Healthy older men (66.4 ± 4.6 years) were assigned to control or experimental (Exp) group (n = 13 per group). The control group performed six sets of ten maximal eccentric contractions (MaxECC) of the knee extensors of non-dominant leg. The Exp group performed six sets of ten low-intensity eccentric contractions of the knee extensors on a leg extension machine by lowering a weight of 10 % maximal voluntary isometric knee extension strength (10 %ECC) 7 days prior to MaxECC. Changes in maximal voluntary isokinetic concentric torque (MVC-CON), angle at peak torque, range of motion (ROM), upper thigh circumference, muscle soreness, plasma creatine kinase activity and myoglobin (Mb) concentration and B-mode ultrasound echo-intensity before and for 5 days after MaxECC were compared between groups by a mixed factor ANOVA. No significant changes in any variables were observed following 10 %ECC. Following MaxECC, all variables changed significantly, and changes in all variables except for angle at peak torque were significantly different between groups. MVC-CON and ROM decreased smaller and recovered faster (P < 0.05) for Exp than control group, and changes in other variables were smaller (P < 0.05) for Exp group compared with control group. These results suggest that preconditioning knee extensor muscles with low-intensity eccentric contractions was effective for attenuating muscle damage induced by subsequent MaxECC of the knee extensors for elderly individuals.

  13. Prosthetic knee design by simulation

    SciTech Connect

    Hollerbach, K; Hollister, A

    1999-07-30

    Although 150,000 total knee replacement surgeries are performed annually in North America, current designs of knee prostheses have mechanical problems that include a limited range of motion, abnormal gait patterns, patellofemoral joint dysfunction, implant loosening or subsidence, and excessive wear. These problems fall into three categories: failure to reproduce normal joint kinematics, which results in altered limb function; bone-implant interface failure; and material failure. Modern computer technology can be used to design, prototype, and test new total knee implants. The design team uses the full range of CAD-CAM to design and produce implant prototypes for mechanical and clinical testing. Closer approximation of natural knee kinematics and kinetics is essential for improved patient function and diminished implant loads. Current knee replacement designs are based on 19th Century theories that the knee moves about a variable axis of rotation. Recent research has shown, however, that knee motion occurs about two fixed, offset axes of rotation. These aces are not perpendicular to the long axes of the bones or to each other, and the axes do not intersect. Bearing surfaces of mechanisms that move about axes of rotation are surfaces of revolution of those axes which advanced CAD technology can produce. Solids with surfaces of revolution for the two axes of rotation for the knee have been made using an HP9000 workstation and Structural Ideas Master Series CAD software at ArthroMotion. The implant's CAD model should closely replicate movements of the normal knee. The knee model will have a range of flexion-extension (FE) from -5 to 120 degrees. Movements include varus, valgus, internal and external rotation, as well as flexion and extension. The patellofemoral joint is aligned perpendicular to the FE axis and replicates the natural joint more closely than those of existing prostheses. The bearing surfaces will be more congruent than current designs and should

  14. Comparison of knee gait kinematics of workers exposed to knee straining posture to those of non-knee straining workers.

    PubMed

    Gaudreault, Nathaly; Hagemeister, Nicola; Poitras, Stéphane; de Guise, Jacques A

    2013-06-01

    Workers exposed to knee straining postures, such as kneeling and squatting, may present modifications in knee gait kinematics that can make them vulnerable to osteoarthritis. In this study, knee kinematics of workers exposed to occupational knee straining postures (KS workers) were compared to those of non-knee straining (non-KS) workers. Eighteen KS workers and 20 non-KS workers participated in the study. Three-dimensional gait kinematic data were recorded at the knee using an electromagnetic motion tracking system. The following parameters were extracted from flexion/extension, adduction/abduction and internal/external rotation angle data and used for group comparisons: knee angle at initial foot contact, peak angles, minimal angles and angle range during the entire gait cycle. Group comparisons were performed with Student t-tests. In the sagittal plane, KS workers had a greater knee flexion angle at initial foot contact, a lower peak knee flexion angle during the swing phase and a lower angle range than non-KS workers (p<0.05). In the frontal plane, all parameters indicated that KS workers had their knees more adducted than non-KS workers. External/internal rotation range was greater for KS workers. This study provides new knowledge on work related to KS postures and knee kinematics. The results support the concept that KS workers might exhibit knee kinematics that are different from those of non-KS workers.

  15. Light: Isometric Casing with Lens, South Elevation, North Elevation, Top ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Light: Isometric Casing with Lens, South Elevation, North Elevation, Top Plan, Base Plan; Fresnel Lens: Isometric, Elevation, Plan - Fort Washington, Fort Washington Light, Northeast side of Potomac River at Fort Washington Park, Fort Washington, Prince George's County, MD

  16. Postactivation Potentiation Biases Maximal Isometric Strength Assessment

    PubMed Central

    Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Oliveira, Thiago Pires; Assumpção, Claudio de Oliveira; Greco, Camila Coelho; Cardozo, Adalgiso Croscato; Denadai, Benedito Sérgio

    2014-01-01

    Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s−1versus 727 ± 158 N·m·s−1), and RMS (59.1 ± 12.2% RMSMAX  versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables. PMID:25133157

  17. Feedforward consequences of isometric contractions: effort and ventilation.

    PubMed

    Luu, Billy L; Smith, Janette L; Martin, Peter G; McBain, Rachel A; Taylor, Janet L; Butler, Jane E

    2016-08-01

    The onset of voluntary muscle contractions causes rapid increases in ventilation and is accompanied by a sensation of effort. Both the ventilatory response and perception of effort are proportional to contraction intensity, but these behaviors have been generalized from contractions of a single muscle group. Our aim was to determine how these relationships are affected by simultaneous contractions of multiple muscle groups. We examined the ventilatory response and perceived effort of contraction during separate and simultaneous isometric contractions of the contralateral elbow flexors and of an ipsilateral elbow flexor and knee extensor. Subjects made 10-sec contractions at 25, 50, and 100% of maximum during normocapnia and hypercapnia. For simultaneous contractions, both muscle groups were activated at the same intensities. Ventilation was measured continuously and subjects rated the effort required to produce each contraction. As expected, ventilation and perceived effort increased proportionally with contraction intensity during individual contractions. However, during simultaneous contractions, neither ventilation nor effort reflected the combined muscle output. Rather, the ventilatory response was similar to when contractions were performed separately, and effort ratings showed a small but significant increase for simultaneous contractions. Hypercapnia at rest doubled baseline ventilation, but did not affect the difference in perceived effort between separate and simultaneous contractions. The ventilatory response and the sense of effort at the onset of muscle activity are not related to the total output of the motor pathways, or the working muscles, but arise from cortical regions upstream from the motor cortex.

  18. Astym® Therapy for the Management of Recalcitrant Knee Joint Stiffness after Total Knee Arthroplasty.

    PubMed

    Bhave, Anil; Corcoran, James; Cherian, Jeffery J; Mont, Michael A

    2016-01-01

    Knee stiffness is a common complication after total knee arthroplasty (TKA). Despite studies published on the surgical management of reduced range of motion (ROM) after TKA, there is limited evidence on the nonoperative management of joint and soft tissue imbalances possibly contributing to reduced knee ROM. This report assesses changes in ROM, pain, function, and patellar tendon length after Astym® joint mobilization use. A 38-year-old male professional skier had a right TKA 3 months before presentation with 2 subsequent manipulations under anesthesia secondary to persistent knee stiffness. He had patellar baja on radiograph, a reduced arc of ROM, reduced patellar mobility and muscular extensibility, and pain to palpation along the patellar tendon. He had 12 visits of physical therapy with the use of Astym®, patellar mobilization, and tibio-femoral mobilizations with movement. The patient also used a customized knee device at home for prolonged knee extension stretching. The patient was treated for 12 visits, along with home use of customized bracing for knee extension. Significant improvements were seen in pain, function, and ROM. He returned to work full-time, ambulated prolonged distances, and negotiated stairs pain-free. He also demonstrated resolution of patellar baja radiographically. Conservative management of recalcitrant knee joint stiffness after primary TKA can be effective in restoring knee mobility and reducing pain and activity limitation. A multimodal approach using Astym® treatment, customized knee bracing, and targeted joint mobilization can be effective in resolving knee joint stiffness.

  19. Physiological response to submaximal isometric contractions of the paravertebral muscles

    NASA Technical Reports Server (NTRS)

    Jensen, B. R.; Jorgensen, K.; Hargens, A. R.; Nielsen, P. K.; Nicolaisen, T.

    1999-01-01

    STUDY DESIGN: Brief (30-second) isometric trunk extensions at 5%, 20%, 40%, 60%, and 80% of maximal voluntary contraction (MVC) and 3 minutes of prolonged trunk extension (20% MVC) in erect position were studied in nine healthy male subjects. OBJECTIVES: To investigate the intercorrelation between intramuscular pressure and tissue oxygenation of the paravertebral muscles during submaximal isometric contractions and further, to evaluate paravertebral electromyogram and intramuscular pressure as indicators of force development. SUMMARY OF BACKGROUND DATA: Local physiologic responses to muscle contraction are incompletely understood. METHODS: Relative oxygenation was monitored with noninvasive near-infrared spectroscopy, intramuscular pressure was measured with a transducer-tipped catheter, and surface electromyogram was monitored at three recording sites. RESULTS: The root mean square amplitudes of the paravertebral electromyogram (L4, left and right; T12, right) and intramuscular pressure measured in the lumbar multifidus muscle at L4 increased with greater force development in a curvilinear manner. A significant decrease in the oxygenation of the lumbar paravertebral muscle in response to muscle contraction was found at an initial contraction level of 20% MVC. This corresponded to a paravertebral intramuscular pressure of 30-40 mm Hg. However, during prolonged trunk extension, no further decrease in tissue oxygenation was found compared with the tissue oxygenation level at the end of the brief contractions, indicating that homeostatic adjustments (mean blood pressure and heart rate) over time were sufficient to maintain paravertebral muscle oxygen levels. CONCLUSION: At a threshold intramuscular pressure of 30-40 mm Hg during muscle contraction, oxygenation in the paravertebral muscles is significantly reduced. The effect of further increase in intramuscular pressure on tissue oxygenation over time may be compensated for by an increase in blood pressure and heart

  20. The effect of short-term isometric training on core/torso stiffness.

    PubMed

    Lee, Benjamin; McGill, Stuart

    2016-09-26

    "Core" exercise is a basic part of many physical training regimens with goals ranging from rehabilitation of spine and knee injuries to improving athletic performance. Core stiffness has been proposed to perform several functions including reducing pain by minimising joint micro-movements, and enhancing strength and speed performance. This study probes the links between a training approach and immediate but temporary changes in stiffness. Passive and active stiffness was measured on 24 participants; 12 having little to no experience in core training (inexperienced), and the other 12 being athletes experienced to core training methods; before and after a 15 min bout of isometric core exercises. Passive stiffness was assessed on a "frictionless" bending apparatus and active stiffness assessed via a quick release mechanism. Short-term isometric core training increased passive and active stiffness in most directions for both inexperienced and experienced participants, passive left lateral bend among experienced participants being the exception (P < 0.05). There was no difference between the inexperienced and experienced groups. The results confirm that the specific isometric training exercise approach tested here can induce immediate changes in core stiffness, in this case following a single session. This may influence performance and injury resilience for a brief period.

  1. Relationship between knee alignment and the electromyographic activity of quadriceps muscles in patients with knee osteoarthritis

    PubMed Central

    Lim, Seong Hoon; Hong, Bo Young; Oh, Jee Hae; Lee, Jong In

    2015-01-01

    [Purpose] We evaluated the relationship between knee alignment and the electromyographic (EMG) activity of the vastus medialis (VM) to the vastus lateralis (VL) muscles in patients with knee osteoarthritis (OA) in a cross-sectional study. [Subjects and Methods] Forty subjects with knee OA were assessed by anatomic radiographic knee alignment and the VM/VL ratio was calculated. Surface EMG from both the VM and VL muscles were evaluated during maximal isometric contraction at 60° knee flexion. Simultaneously, peak quadriceps torque was assessed using an isokinetic dynamometer. Subjects were categorized into low, moderate, and high varus groups according to knee malalignment. The peak quadriceps torque and VM/VL ratio across groups, and their relationships with varus malalignment were analyzed. [Results] All subjects had medial compartment OA and the VM/VL ratio of all subjects was 1.31 ± 0.28 (mean ± SD). There were no significant differences in the peak quadriceps torque or VM/VL ratios across the groups nor were there any significant relationships with varus malalignment. [Conclusion] The VM/VL ratio and peak quadriceps torque were not associated with the severity of knee varus malalignment. PMID:25995602

  2. Correlation between architectural variables and torque in the erector spinae muscle during maximal isometric contraction.

    PubMed

    Cuesta-Vargas, Antonio; González-Sánchez, Manuel

    2014-01-01

    This study analysed whether a significant relationship exists between the torque and muscle thickness and pennation angle of the erector spinae muscle during a maximal isometric lumbar extension with the lumbar spine in neutral position. This was a cross-sectional study in which 46 healthy adults performed three repetitions for 5 s of maximal isometric lumbar extension with rests of 90 s. During the lumbar extensions, bilateral ultrasound images of the erector spinae muscle (to measure pennation angle and muscle thickness) and torque were acquired. Reliability test analysis calculating the internal consistency (Cronbach's alpha) of the measure, correlation between pennation angle, muscle thickness and torque extensions were examined. Through a linear regression the contribution of each independent variable (muscle thickness and pennation angle) to the variation of the dependent variable (torque) was calculated. The results of the reliability test were: 0.976-0.979 (pennation angle), 0.980-0.980 (muscle thickness) and 0.994 (torque). The results show that pennation angle and muscle thickness were significantly related to each other with a range between 0.295 and 0.762. In addition, multiple regression analysis showed that the two variables considered in this study explained 68% of the variance in the torque. Pennation angle and muscle thickness have a moderate impact on the variance exerted on the torque during a maximal isometric lumbar extension with the lumbar spine in neutral position.

  3. Knee Injuries

    MedlinePlus

    ... keeping it from bending outward. anterior cruciate ligament (ACL): The ACL connects your femur to your tibia at the ... Common knee sprains usually involve damage to the ACL and/or MCL. The most serious sprains involve ...

  4. Knee MRI

    MedlinePlus

    ... of the knee uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of ... scans, MRI does not utilize ionizing radiation. Instead, radio waves redirect alignment of hydrogen atoms that naturally exist ...

  5. Knee Dislocations

    PubMed Central

    Schenck, Robert C.; Richter, Dustin L.; Wascher, Daniel C.

    2014-01-01

    Background: Traumatic knee dislocation is becoming more prevalent because of improved recognition and increased exposure to high-energy trauma, but long-term results are lacking. Purpose: To present 2 cases with minimum 20-year follow-up and a review of the literature to illustrate some of the fundamental principles in the management of the dislocated knee. Study Design: Review and case reports. Methods: Two patients with knee dislocations who underwent multiligamentous knee reconstruction were reviewed, with a minimum 20-year follow-up. These patients were brought back for a clinical evaluation using both subjective and objective measures. Subjective measures include the following scales: Lysholm, Tegner activity, visual analog scale (VAS), Short Form–36 (SF-36), International Knee Documentation Committee (IKDC), and a psychosocial questionnaire. Objective measures included ligamentous examination, radiographic evaluation (including Telos stress radiographs), and physical therapy assessment of function and stability. Results: The mean follow-up was 22 years. One patient had a vascular injury requiring repair prior to ligament reconstruction. The average assessment scores were as follows: SF-36 physical health, 52; SF-36 mental health, 59; Lysholm, 92; IKDC, 86.5; VAS involved, 10.5 mm; and VAS uninvolved, 2.5 mm. Both patients had excellent stability and were functioning at high levels of activity for their age (eg, hiking, skydiving). Both patients had radiographic signs of arthritis, which lowered 1 subject’s IKDC score to “C.” Conclusion: Knee dislocations have rare long-term excellent results, and most intermediate-term studies show fair to good functional results. By following fundamental principles in the management of a dislocated knee, patients can be given the opportunity to function at high levels. Hopefully, continued advances in the evaluation and treatment of knee dislocations will improve the long-term outcomes for these patients in the

  6. Effect of Preactivation on Torque Enhancement by the Stretch-Shortening Cycle in Knee Extensors

    PubMed Central

    Fukutani, Atsuki; Misaki, Jun; Isaka, Tadao

    2016-01-01

    The stretch-shortening cycle is one of the most interesting topics in the field of sport sciences, because the performance of human movement is enhanced by the stretch-shortening cycle (eccentric contraction). The purpose of the present study was to examine whether the influence of preactivation on the torque enhancement by stretch-shortening cycle in knee extensors. Twelve men participated in this study. The following three conditions were conducted for knee extensors: (1) concentric contraction without preactivation (CON), (2) concentric contraction with eccentric preactivation (ECC), and (3) concentric contraction with isometric preactivation (ISO). Muscle contractions were evoked by electrical stimulation to discard the influence of neural activity. The range of motion of the knee joint was set from 80 to 140 degrees (full extension = 180 degrees). Angular velocities of the concentric and eccentric contractions were set at 180 and 90 degrees/s, respectively. In the concentric contraction phase, joint torques were recorded at 85, 95, and 105 degrees, and they were compared among the three conditions. In the early phase (85 degrees) of concentric contraction, the joint torque was larger in the ECC and ISO conditions than in the CON condition. However, these clear differences disappeared in the later phase (105 degrees) of concentric contraction. The results showed that joint torque was clearly different among the three conditions in the early phase whereas this difference disappeared in the later phase. Thus, preactivation, which is prominent in the early phase of contractions, plays an important role in torque enhancement by the stretch-shortening cycle in knee extensors. PMID:27414804

  7. Effect of long-term isometric training on core/torso stiffness.

    PubMed

    Lee, Benjamin C Y; McGill, Stuart M

    2015-06-01

    Although core stiffness enhances athletic performance traits, controversy exists regarding the effectiveness of isometric vs. dynamic core training methods. This study aimed to determine whether long-term changes in stiffness can be trained, and if so, what is the most effective method. Twenty-four healthy male subjects (23 ± 3 years; 1.8 ± 0.06 m; 77.5 ± 10.8 kg) were recruited for passive and active stiffness measurements before and after a 6-week core training intervention. Twelve subjects (22 ± 2 years; 1.8 ± 0.08 m; 78.3 ± 12.3 kg) were considered naive to physical and core exercise. The other 12 subjects (24 ± 3 years; 1.8 ± 0.05 m; 76.8 ± 9.7 kg) were Muay Thai athletes (savvy). A repeated-measures design compared core training methods (isometric vs. dynamic, with a control group) and subject training experience (naive vs. savvy) before and after a 6-week training period. Passive stiffness was assessed on a "frictionless" bending apparatus and active stiffness assessed through a quick release mechanism. Passive stiffness increased after the isometric training protocol. Dynamic training produced a smaller effect, and as expected, there was no change in the control group. Active stiffness did not change in any group. Comparisons between subject and training groups did not reveal any interactions. Thus, an isometric training approach was superior in terms of enhancing core stiffness. This is important since increased core stiffness enhances load bearing ability, arrests painful vertebral micromovements, and enhances ballistic distal limb movement. This may explain the efficacy reported for back and knee injury reduction.

  8. The effects of isometric wall squat exercise on heart rate and blood pressure in a normotensive population.

    PubMed

    Goldring, Natalie; Wiles, Jonathan D; Coleman, Damian

    2014-01-01

    The isometric wall squat could be utilised in home-based training aimed at reducing resting blood pressure, but first its suitability must be established. The aim of this study was to determine a method of adjusting wall squat intensity and explore the cardiovascular responses. Twenty-three participants performed one 2 minute wall squat on 15 separate occasions. During the first ten visits, ten different knee joint angles were randomly completed from 135° to 90° in 5° increments; five random angles were repeated in subsequent visits. Heart rate and blood pressure (systolic, diastolic and mean arterial pressure) were measured. The heart rate and blood pressure parameters produced significant inverse relationships with joint angle (r at least -0.80; P < 0.05), demonstrating that wall squat intensity can be adjusted by manipulating knee joint angle. Furthermore, the wall squat elicited similar cardiovascular responses to other isometric exercise modes that have reduced resting blood pressure (135° heart rate: 76 ± 10 beats ∙ min(-1); systolic: 134 ± 14 mmHg; diastolic: 76 ± 6 mmHg and 90° heart rate: 119 ± 20 beats ∙ min(-1); systolic: 196 ± 18 mmHg; diastolic: 112 ± 13 mmHg). The wall squat may have a useful role to play in isometric training aimed at reducing resting blood pressure.

  9. Improved Automatically Locking/Unlocking Orthotic Knee Joint

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1995-01-01

    Proposed orthotic knee joint improved version of one described in "Automatically Locking/Unlocking Orthotic Knee Joint" (MFS-28633). Locks automatically upon initial application of radial force (wearer's weight) and unlocks automatically, but only when all loads (radial force and bending) relieved. Joints lock whenever wearer applies weight to knee at any joint angle between full extension and 45 degree bend. Both devices offer increased safety and convenience relative to conventional orthotic knee joints.

  10. Hiking physiology and the "quasi-isometric" concept.

    PubMed

    Spurway, Neil C

    2007-08-01

    The literature indicates that the heart rate of a planing-dinghy sailor, in winds of 4 - 5 m . s(-1), is in the range seen in aerobic athletes, yet oxygen consumption (VO(2)) is roughly half that of the same individual cycling at that heart rate. Thus, although upper-body dynamic activity is a contributing factor, the dominant physiological demand must be the "quasi-isometric" stress on the lower-body anterior muscles - especially the quadriceps, which appears to impose 40 - 50% of the total oxygen demand in a typical hiking posture. Therefore, a non-trivial part of the sailor's fitness training should involve sustained quadriceps stress. Estimates of this stress on water vary widely in the literature, but about 25 - 30% maximal voluntary contraction (MVC) tallies with endurance times recorded both in the literature and in an outline of new work reported here. Muscle blood flow is restricted under such a load, but not occluded. Laser Doppler measurements of femoral blood flow on a leg-extension ergometer found similar values during 10 - 30% MVC, much less at 40%, and marked hyperaemia on relaxation from 20% MVC or more - implying metabolic debt. Adding low-amplitude alternating leg movements while holding the same overall load stationary, and therefore increasing only internal not external work, further elevates blood flow and VO(2) both during and after exercise. Femoral-vein lactate concentration is also higher after these movements. Speculations that unusually dynamic lower-body movements by elite sailors might assist hiking endurance are not supported by these findings. Nevertheless, afloat or ashore, capillary lactate concentrations hardly ever exceed 5 mmol . l(-1), even during the post-exercise surge - challenging assumptions that the quadriceps had been profoundly anaerobic while under load. On the contrary, it appears that aerobic metabolism contributes substantially, if not completely, to energy supply. A preliminary comparison of elite sailors with

  11. KNEE-JOINT LOADING IN KNEE OSTEOARTHRITIS: INFLUENCE OF ABDOMINAL AND THIGH FAT

    PubMed Central

    Messier, Stephen P.; Beavers, Daniel P.; Loeser, Richard F.; Carr, J. Jeffery; Khajanchi, Shubham; Legault, Claudine; Nicklas, Barbara J.; Hunter, David J.; DeVita, Paul

    2014-01-01

    Purpose Using three separate models that included total body mass, total lean and total fat mass, and abdominal and thigh fat as independent measures, we determined their association with knee-joint loads in older overweight and obese adults with knee osteoarthritis (OA). Methods Fat depots were quantified using computed tomography and total lean and fat mass determined with dual energy x-ray absorptiometry in 176 adults (age = 66.3 yr., BMI = 33.5 kg·m−2) with radiographic knee OA. Knee moments and joint bone-on-bone forces were calculated using gait analysis and musculoskeletal modeling. Results Higher total body mass was significantly associated (p ≤ 0.0001) with greater knee compressive and shear forces, compressive and shear impulses (p < 0.0001), patellofemoral forces (p< 0.006), and knee extensor moments (p = 0.003). Regression analysis with total lean and total fat mass as independent variables revealed significant positive associations of total fat mass with knee compressive (p = 0.0001), shear (p < 0.001), and patellofemoral forces (p = 0.01) and knee extension moment (p = 0.008). Gastrocnemius and quadriceps forces were positively associated with total fat mass. Total lean mass was associated with knee compressive force (p = 0.002). A regression model that included total thigh and total abdominal fat found both were significantly associated with knee compressive and shear forces (p ≤ 0.04). Thigh fat was associated with the knee abduction (p = 0.03) and knee extension moment (p = 0.02). Conclusions Thigh fat, consisting predominately of subcutaneous fat, had similar significant associations with knee joint forces as abdominal fat despite its much smaller volume and could be an important therapeutic target for people with knee OA. PMID:25133996

  12. Knee Menisci.

    PubMed

    Bryceland, James Kevin; Powell, Andrew John; Nunn, Thomas

    2017-04-01

    The menisci of the knees are semicircular fibrocartilaginous structures consisting of a hydrophilic extracellular matrix containing a network of collagen fibers, glycoproteins, and proteoglycans maintained by a cellular component. The menisci are responsible for more than 50% of load transmission across the knee and increase joint congruity thereby also aiding in fluid film lubrication of the joint. In the United Kingdom, meniscal tears are the most common form of intra-articular knee injury and one of the commonest indications for orthopedic intervention. The management of these injuries is dependent on the location within the meniscus (relative to peripheral blood supply) and the pattern of tear. Removal of meniscus is known to place the knee at increased risk of osteoarthritis; therefore repair of meniscal tears is preferable. However, a significant proportion of tears are irreparable and can only be treated by partial or even complete meniscectomy. More recent studies have shown encouraging results with meniscal replacement in this situation, though further work is required in this area.

  13. Gap balancing in total knee arthroplasty.

    PubMed

    Bottros, John; Gad, Bishoy; Krebs, Viktor; Barsoum, Wael K

    2006-06-01

    It is well known that the success of total knee arthroplasty is collectively dependent on the proper recreation of the joint line, appropriate soft tissue balancing, and respectful management of the extensor mechanism. One of the most decisive factors within the surgeon's control is the reestablishment of proper knee kinematics through both medial-lateral and flexion-extension ligamentous balancing. This can be accomplished only by a comprehensive intraoperative evaluation in full flexion, mid flexion, and full extension to minimize potential gap mismatches. Most of the discussion will focus on this aspect of soft tissue balancing, but this does not undermine the importance of the other aforementioned principles of successful knee arthroplasty.

  14. Maximal force during eccentric and isometric actions at different elbow angles.

    PubMed

    Linnamo, V; Strojnik, V; Komi, P V

    2006-04-01

    The purpose of this study was to examine a course of force potentiation and/or inhibition during maximal voluntary eccentric action. Maximal voluntary force (MVC) of elbow flexion of ten healthy male volunteers was measured during isometric and isokinetic eccentric action starting from 80 degrees or 110 degrees and ending at 140 degrees elbow angle. Surface EMG was recorded from biceps brachii (BB) and brachioradialis (BR) muscles. Maximal voluntary eccentric force during the first 10 degrees of the movement was higher (P<0.001) than the maximal voluntary isometric preactivation force both in 80 degrees and in 110 degrees starting position at all three velocities (1, 2, and 4 rad s(-1)). The relative force potentiation was velocity dependent being smallest at the lowest stretching speed (P<0.01). Average EMG (aEMG) of BB and BR decreased as the joint angle increased both in eccentric and in isometric actions but the decrease in aEMG towards extension was somewhat higher in eccentric actions as compared to isometric. It was concluded that the force measured during the first 10 degrees of eccentric contraction always exceeded the maximal voluntary isometric preactivation force regardless of the joint angle or of the movement velocity. When maximal voluntary preactivation preceded the stretch, the relative force potentiation seemed to be greater at higher stretching velocities (velocity dependent) while at lower preactivation levels, the velocity dependence was not observed. Decreased muscle activation and lower maximal voluntary force towards the end of the movement suggested inhibition during maximal voluntary eccentric actions.

  15. Efficacy of multimodal, systematic non-surgical treatment of knee osteoarthritis for patients not eligible for a total knee replacement: a study protocol of a randomised controlled trial

    PubMed Central

    Skou, Soren Thorgaard; Roos, Ewa M; Laursen, Mogens Berg; Rathleff, Michael Skovdal; Arendt-Nielsen, Lars; Simonsen, Ole; Rasmussen, Sten

    2012-01-01

    Introduction It is recommended that non-operative treatment of knee osteoarthritis (KOA) should be individually tailored and include multiple treatment modalities. Despite these recommendations, no one has yet investigated the efficacy of combining several non-surgical treatment modalities in a randomised controlled study. The purpose of this randomised controlled study is to examine if an optimised, combined non-surgical treatment programme results in greater improvements in pain, function and quality of life in comparison with usual care in patients with KOA who are not eligible for total knee arthroplasty (TKA). Methods and analysis This study will include 100 consecutive patients from the North Denmark Region not eligible for TKA with radiographic KOA (K-L grade ≥1) and mean pain during the previous week of ≤60 mm (0–100). The participants will be randomised to receive either a 12-week non-surgical treatment programme consisting of patient education, exercise, diet, insoles, paracetamol and/or NSAIDs or usual care (two information leaflets containing information on KOA and advice regarding the above non-surgical treatment). The primary outcome will be the change from baseline to 12 months on the self-report questionnaire Knee Injury and Osteoarthritis Outcome Score (KOOS)4 defined as the average score for the subscale scores for pain, symptoms, activities of daily living and quality of life. Secondary outcomes include the five individual KOOS subscale scores, pain on a 100 mm Visual Analogue Scale, EQ-5D, self-efficacy, pain pressure thresholds, postural control and isometric knee flexion and knee extension strength. Ethics and dissemination This study was approved by the local Ethics Committee of The North Denmark Region (N-20110085) and the protocol conforms to the principles of the Declaration of Helsinki. Data collection will be completed by April 2014. Publications will be ready for submission in the summer of 2014. Trial registration number

  16. Techniques for assessing knee joint pain in arthritis

    PubMed Central

    Neugebauer, Volker; Han, Jeong S; Adwanikar, Hita; Fu, Yu; Ji, Guangchen

    2007-01-01

    The assessment of pain is of critical importance for mechanistic studies as well as for the validation of drug targets. This review will focus on knee joint pain associated with arthritis. Different animal models have been developed for the study of knee joint arthritis. Behavioral tests in animal models of knee joint arthritis typically measure knee joint pain rather indirectly. In recent years, however, progress has been made in the development of tests that actually evaluate the sensitivity of the knee joint in arthritis models. They include measurements of the knee extension angle struggle threshold, hind limb withdrawal reflex threshold of knee compression force, and vocalizations in response to stimulation of the knee. A discussion of pain assessment in humans with arthritis pain conditions concludes this review. PMID:17391515

  17. The Adaptive Range of 1/f Isometric Force Production

    ERIC Educational Resources Information Center

    Sosnoff, Jacob J.; Valantine, Andrew D.; Newell, Karl M.

    2009-01-01

    The adaptive range of 1/f dynamics in isometric force output was investigated. Participants produced isometric force to targets with predictable demands (constant and sinusoidal) and 1/f noise waveforms (white, pink, brown, and black) that also varied in the frequency bandwidth represented in the force signal (0-4 Hz, 0-8 Hz, and 0-12 Hz). The…

  18. Isometric deformations of planar quadrilaterals with constant index

    SciTech Connect

    Zaputryaeva, E S

    2014-05-31

    We consider isometric deformations (motions) of polygons (so-called carpenter's rule problem) in the case of self-intersecting polygons with the additional condition that the index of the polygon is preserved by the motion. We provide general information about isometric deformations of planar polygons and give a complete solution of the carpenter's problem for quadrilaterals. Bibliography: 17 titles.

  19. Isometric deformations of planar quadrilaterals with constant index

    NASA Astrophysics Data System (ADS)

    Zaputryaeva, E. S.

    2014-05-01

    We consider isometric deformations (motions) of polygons (so-called carpenter's rule problem) in the case of self-intersecting polygons with the additional condition that the index of the polygon is preserved by the motion. We provide general information about isometric deformations of planar polygons and give a complete solution of the carpenter's problem for quadrilaterals. Bibliography: 17 titles.

  20. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... scanners can perform the exam without stopping.) A computer makes several images of the body area. These ...

  1. Knee pain (image)

    MedlinePlus

    ... front of the knee can be due to bursitis, arthritis, or softening of the patella cartilage as ... knee. Overall knee pain can be due to bursitis, arthritis, tears in the ligaments, osteoarthritis of the ...

  2. Total Knee Replacement

    MedlinePlus

    ... stability. The long thigh muscles give the knee strength. All remaining surfaces of the knee are covered ... physical examination. This will assess knee motion, stability, strength, and overall leg alignment. • X-rays. These images ...

  3. Knee joint replacement

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002974.htm Knee joint replacement To use the sharing features on this page, please enable JavaScript. Knee joint replacement is a surgery to replace a knee ...

  4. Water on the Knee

    MedlinePlus

    ... your knee joint. Some people call this condition "water on the knee." A swollen knee may be ... Choose low-impact exercise. Certain activities, such as water aerobics and swimming, don't place continuous weight- ...

  5. Knee joint functional range of movement prior to and following total knee arthroplasty measured using flexible electrogoniometry.

    PubMed

    Myles, Christine M; Rowe, Philip J; Walker, Colin R C; Nutton, Richard W

    2002-08-01

    The functional ranges of movement of the knee were investigated in a group of patients with knee osteoarthritis (n = 42, mean age 70 years) before, 4 months and at 18-24 months after total knee arthroplasty and then compared with age matched normal subjects (n = 20, mean age 67 years). Flexible electrogoniometry was used to record the maximum flexion-extension angle, the minimum flexion-extension angle and flexion-extension excursions of both knees during eleven functional activities along with the active and passive knee joint range of motion measured using a manual goniometer. Over the eleven functional activities the patients pre-operatively exhibited 28% less knee joint excursion than normal age matched subjects. By 18-24 months following total knee arthroplasty only 2% of this deficit was recovered. Statistically this recovery was only significant in level walking, slope ascent and slope descent. A greater range of movement was measured in a non-weight bearing position than was used in weight bearing functional activity. It is concluded that total knee arthroplasty gives rise to little improvement in knee motion during functional activities and that functional range of movement of the knee remains limited when compared to normal knee function for a minimum of 18 months following operation.

  6. Arthroscopic knee debridement can delay total knee replacement in painful moderate haemophilic arthropathy of the knee in adult patients.

    PubMed

    Rodriguez-Merchan, E Carlos; Gomez-Cardero, Primitivo

    2016-09-01

    The role of arthroscopic debridement of the knee in haemophilia is controversial in the literature. The purpose of this study is to describe the results of arthroscopic knee debridement (AKD), with the aim of determining whether it is possible to delay total knee replacement (TKR) for painful moderate haemophilic arthropathy of the knee in adult patients. In a 14-year period (1998-2011), AKD was performed for moderate haemophilic arthropathy of the knee in 27 patients with haemophilia A. Their average age at operation was 28.6 years (range 26-39 years). Indications for surgery were as follows: more than 90° of knee flexion, flexion deformity less than 30°, good axial alignment of the knee, good patellar alignment, and pain above >60 points in a visual analogue scale [0 (no pain) to 100 points]. Secondary haematological prophylaxis and rehabilitation (physiotherapy) was given for at least 3 months after surgery. Follow-up was for an average of 7.5 years (range 2-14 years). We assessed the clinical outcome before surgery and at the time of latest follow-up using the Knee Society pain and function scores, the range of motion, and the radiological score of the World Federation of Haemophilia. Knee Society pain scores improved from 39 preoperatively to 66 postoperatively, and function scores improved from 36 to 52. Range of motion improved on an average from -15° of extension and 90° of flexion before surgery, to -5° of extension and 110° of flexion at the last follow-up. A radiological deterioration of 2.8 points on average was found. There were two (7.4%) postoperative complications (haemarthroses resolved by joint aspiration). One patient (3.7%) required a TKR 12.5 years later. AKD should be considered in painful moderate haemophilic arthropathy of the knee in adult patients to delay TKR.

  7. Six degree-of-freedom knee joint kinematics in obese individuals with knee pain during gait

    PubMed Central

    Li, Jing-Sheng; Tsai, Tsung-Yuan; Felson, David T.; Li, Guoan; Lewis, Cara L.

    2017-01-01

    Knee joint pain is a common symptom in obese individuals and walking is often prescribed as part of management programs. Past studies in obese individuals have focused on standing alignment and kinematics in the sagittal and coronal planes. Investigation of 6 degree-of-freedom (6DOF) knee joint kinematics during standing and gait is important to thoroughly understand knee function in obese individuals with knee pain. This study aimed to investigate the 6DOF knee joint kinematics in standing and during gait in obese patients using a validated fluoroscopic imaging system. Ten individuals with obesity and knee pain were recruited. While standing, the knee was in 7.4±6.3°of hyperextension, 2.8±3.3° of abduction and 5.6±7.3° of external rotation. The femoral center was located 0.7±3.1mm anterior and 5.1±1.5mm medial to the tibial center. During treadmill gait, the sagittal plane motion, i.e., flexion/extension and anterior-posterior translation, showed a clear pattern. Specifically, obese individuals with knee pain maintained the knee in more flexion and more anterior tibial translation during most of the stance phase of the gait cycle and had a reduced total range of knee flexion when compared to a healthy non-obese group. In conclusion, obese individuals with knee pain used hyperextension knee posture while standing, but maintained the knee in more flexion during gait with reduced overall range of motion in the 6DOF analysis. PMID:28339477

  8. Knee kinetic pattern during gait and anterior knee pain before and after rehabilitation in patients with patellofemoral pain syndrome.

    PubMed

    Claudon, B; Poussel, M; Billon-Grumillier, C; Beyaert, C; Paysant, J

    2012-05-01

    Patellofemoral pain is likely due to compressive force acting on the patella related in turn to knee extension moment. The latter variable was assumed to be (i) reduced during short-distance free walking in case of patellofemoral pain syndrome and (ii) increased after therapeutic pain reduction. Peak knee extension moment at beginning of stance phase was recorded by three-dimensional gait analysis in 22 controls and in 23 patients with patellofemoral pain syndrome before and after rehabilitation of knee extensors and flexors to reduce the pain. Pain would occur mainly in stressful activities such as stair negotiation or squatting and was quantified by the anterior knee pain scale. Peak knee extension moment was significantly reduced in all the patients before treatment (n=23) compared to controls, although no one had pain during free walking. In the 17 patients who experienced significant post-rehabilitation pain reduction in their stressful activities, the peak knee extension moment was significantly reduced before treatment compared to controls and significantly increased after treatment, reaching values similar to control values. The peak knee extension moment during free walking appears to be a good kinetic variable related to a compensatory mechanism limiting or avoiding anterior knee pain and may be of interest in assessing knee dynamics alteration in patients with PFPS.

  9. Lumbosacral compression in maximal lifting efforts in sagittal plane with varying mechanical disadvantage in isometric and isokinetic modes.

    PubMed

    Kumar, S

    1994-12-01

    Nine normal male subjects (mean age 28.2 years and mean weight 72.6 kg) performed 20 standardized maximal effort lifting tasks. They were asked to perform stoop and squat lifts at half, three-quarters and full individual horizontal reach distances in mid-sagittal plane in isometric and isokinetic modes (fixed velocity 60 cm/s). Both stoop and squat lifts were initiated at the floor level and terminated at the individual's knuckle height keeping the horizontal distance constant throughout the lift. The isometric stoop lifts were performed with hip at 60 degrees and 90 degrees of flexion with hands at preselected reach distances. The isometric squat lifts were performed with knees at 90 degrees and 135 degrees of flexion with hands at similarly preselected reach distances. The force was measured using a Static Dynamic Strength Tester with load cell (SM 1000). The postures were recorded using a two-dimensional Peak Performance System with an event synchronizing unit. The load cell was sampled at 60 Hz and the video filming was done at 60 frames per second. The force and postural data were fed to a biomechanical model (Cheng and Kumar 1991) to extract external moment and lumbosacral compression. The strengths generated in different conditions were significantly different (p < 0.01). The strength variation ranged by up to 73% whereas the lumbosacral compression varied by only up to 15%. A high level of lumbosacral compression was maintained in all conditions.

  10. Knee Injuries and Disorders

    MedlinePlus

    Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt ... your life. The most common disease affecting the knee is osteoarthritis. The cartilage in the knee gradually wears away, ...

  11. Intraoperative knee anthropometrics: correlation with cartilage wear.

    PubMed

    Rooney, N; Fitzpatrick, D P; Beverland, D E

    2006-08-01

    Accurate knee morphology is of value in determining the correct sizing of prosthetic implants. Intraoperative measurement of key linear dimensional variables was carried out on 196 Caucasian knees (osteoarthritic patients: 68 male and 128 female). Of the 196 knees measured, 70 had extensive cartilage degeneration. Statistical analysis was carried out on this large sample size of data. Summary statistics and correlation coefficients between variables were determined and compared between subgroups. Male knees were on average larger than female knees. Higher correlation was found between variables for males than between variables for females. Overall, the patellar dimensions were seen to correlate least well with other anatomical variables. High correlation between femoral variables supports current femoral sizing procedure, although routine patellar resection practices are called into question. Average values for the 70 knees with extensive cartilage degeneration were significantly smaller (P < 0.01) than their counterparts for the other 126 knees. For a measurement not containing cartilage, such as femoral epicondylar width, this difference cannot be accounted for by the loss of cartilage owing to wear. This suggests that, for similar height and weight, a naturally narrower femoral epicondylar width may be associated with severe osteoarthritis.

  12. [Chronic knee joint discomfort].

    PubMed

    Wittke, R

    2005-06-23

    Chronic pain in the knee joint is frequently a sign of arthrosis in adults. This must be clearly differentiated from other knee problems. Patellofemoral stress syndrome (occurs mostly in young people) and arthritis with effusion in the knee joint after long and mostly unusual stress also allow only a reduced function of the knee joint. However, even when the knee joint is still fully functional, chronic problems could already exist: For example, for joggers, iliotibial band friction syndrome (runner's knee) or after high unphysiological stress, patellar tendinopathy (jumper's knee). These must be differentiated from pes anserinus syndrome and a plica mediopatellaris.

  13. Functional performance, maximal strength, and power characteristics in isometric and dynamic actions of lower extremities in soccer players.

    PubMed

    Requena, Bernardo; González-Badillo, Juan José; de Villareal, Eduardo Saez Saez; Ereline, Jaan; García, Inmaculada; Gapeyeva, Helena; Pääsuke, Mati

    2009-08-01

    The purposes of the present study were to determine muscle strength and power output characteristics in a group of professional soccer players and to identify their relationships with 2 functional performance tests (vertical jumping height and 15-m sprint time). Maximal strength and power indices attained against different loads in barbell back squat exercise, isometric maximal force of the knee extensor and plantar flexor muscles, isokinetic peak torque of the knee extensors muscles, vertical jumping height in squat and counter-movement jumps, and 15-m sprint time tests were assessed in 21 semiprofessional soccer players (age 20 +/- 3.8 years). Correlation analyses were performed to examine the relationship between each of these measures. The main results of the present study were that (a) maximal power in concentric half-squat exercise was attained with a load of 60% of 1 repetition maximum, representing 112% of body weight; (b) the performance in the functional tests selected was significantly related with all the half-squat variables measured, especially with loads of 75-125% of body weight; and (c) low to nonsignificant correlations were found between functional tests performance and isometric and isokinetic muscle strength measures. It was concluded that in semiprofessional soccer players (a) isometric and isokinetic muscle strength assessed in an open kinetic chain were not movement-specific enough to predict performance during a more complex movement, such as jump or sprint and (b) concentric half-squat exercise was principally related with the functional tests selected when it was performed against external loading within the range of the load in case of which the maximal power output was attained.

  14. An Investigation Into the Relationship Between Maximum Isometric Strength and Vertical Jump Performance.

    PubMed

    Thomas, Christopher; Jones, Paul A; Rothwell, James; Chiang, Chieh Y; Comfort, Paul

    2015-08-01

    Research has demonstrated a clear relationship between dynamic strength and vertical jump (VJ) performance; however, the relationship of isometric strength and VJ performance has been studied less extensively. The aim of this study was to determine the relationship between isometric strength and performance during the squat jump (SJ) and countermovement jump (CMJ). Twenty-two male collegiate athletes (mean ± SD; age = 21.3 ± 2.9 years; height = 175.63 ± 8.23 cm; body mass = 78.06 ± 10.77 kg) performed isometric midthigh pulls (IMTPs) to assess isometric peak force (IPF), maximum rate of force development, and impulse (IMP) (I100, I200, and I300). Force-time data, collected during the VJs, were used to calculate peak velocity, peak force (PF), peak power (PP), and jump height. Absolute IMTP measures of IMP showed the strongest correlations with VJ PF (r = 0.43-0.64; p ≤ 0.05) and VJ PP (r = 0.38-0.60; p ≤ 0.05). No statistical difference was observed in CMJ height (0.33 ± 0.05 m vs. 0.36 ± 0.05 m; p = 0.19; ES = -0.29) and SJ height performance (0.29 ± 0.06 m vs. 0.33 ± 0.05 m; p = 0.14; ES = -0.34) when comparing stronger to weaker athletes. The results of this study illustrate that absolute IPF and IMP are related to VJ PF and PP but not VJ height. Because stronger athletes did not jump higher than weaker athletes, dynamic strength tests may be more practical methods of assessing the relationships between relative strength levels and dynamic performance in collegiate athletes.

  15. Comparison of sympathetic nerve responses to neck and forearm isometric exercise

    NASA Technical Reports Server (NTRS)

    Steele, S. L. Jr; Ray, C. A.

    2000-01-01

    PURPOSE: Although the autonomic and cardiovascular responses to arm and leg exercise have been studied, the sympathetic adjustments to exercise of the neck have not. The purpose of the present study was twofold: 1) to determine sympathetic and cardiovascular responses to isometric contractions of the neck extensors and 2) to compare sympathetic and cardiovascular responses to isometric exercise of the neck and forearm. METHODS: Muscle sympathetic nerve activity (MSNA), mean arterial pressure (MAP), and heart rate were measured in nine healthy subjects while performing isometric neck extension (INE) and isometric handgrip (IHG) in the prone position. After a 3-min baseline period, subjects performed three intensities of INE for 2.5 min each: 1) unloaded (supporting head alone), 2) 10% maximal voluntary contraction (MVC), and 3) 30% MVC, then subjects performed two intensities (10% and 30% MVC) of IHG for 2.5 min. RESULTS: Supporting the head by itself did not significantly change any of the variables. During [NE, MAP significantly increased by 10 +/- 2 and 31 +/- 4 mm Hg and MSNA increased by 67 +/- 46 and 168 +/- 36 units/30 s for 10% and 30% MVC, respectively. IHG and INE evoked similar responses at 10% MVC, but IHG elicited higher peak MAP and MSNA at 30% MVC (37 +/- 7 mm Hg (P < 0.05) and 300 +/- 48 units/30 s (P < 0.01) for IHG, respectively). CONCLUSIONS: The data indicate that INE can elicit marked increases in MSNA and cardiovascular responses but that it evokes lower peak responses as compared to IHG. We speculate that possible differences in muscle fiber type composition, muscle mass, and/or muscle architecture of the neck and forearm are responsible for these differences in peak responses.

  16. Cutaway Isometric, Upper Chord (Compression Joint), Lower Chord (Tension Splice) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cutaway Isometric, Upper Chord (Compression Joint), Lower Chord (Tension Splice) - McConnell's Mill Bridge, Spanning Slippery Rock Creek at McConnell's Mill Road (Township Route 415), Ellwood City, Lawrence County, PA

  17. Elevations, Major Component Isometric, Propellant Flow Schematic, and External Tank ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Elevations, Major Component Isometric, Propellant Flow Schematic, and External Tank Connection to Shuttle Main Engines - Space Transportation System, Space Shuttle Main Engine, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  18. 41. OPERATING CORRIDOR PLAN AND SECTIONS, INCLUDING SOME ISOMETRIC DETAILS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. OPERATING CORRIDOR PLAN AND SECTIONS, INCLUDING SOME ISOMETRIC DETAILS. INEEL DRAWING NUMBER 200-0633-00-287-106455. FLUOR NUMBER 5775-CPP-633-P-60 - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

  19. 45. Photographic reproduction of construction drawing: "Launch Control Facility, Isometric." ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. Photographic reproduction of construction drawing: "Launch Control Facility, Isometric." - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

  20. Typing keystroke duration changed after submaximal isometric finger exercises.

    PubMed

    Joe Chang, Che-Hsu; Johnson, Peter W; Katz, Jeffrey N; Eisen, Ellen A; Dennerlein, Jack T

    2009-01-01

    A repeated-measures laboratory experiment tested whether keystroke duration during touch-typing changes after a finger performs submaximal isometric flexion exercises. Fourteen right-handed touch-typists used right ring finger to perform three 15-min exercise conditions, two isometric exercises and a no-force condition, each on a separate day. Before and after each exercise condition, typing keystroke duration and isometric force elicited by electrical stimulation were measured for right ring finger. Keystroke duration of right ring finger decreased by 5% (6 ms, P < 0.05) immediately after the exercises but not after the no-force condition. Peak isometric finger force elicited by electrical stimulation decreased by 17-26% (P < 0.05) for the flexor digitorum superficialis and decreased by 4-8% for the extensor digitorum communis after the isometric exercises. After the finger was exposed to isometric exercises, changes in typing keystroke duration coincided with changes in the physiological state of the finger flexor and extensor muscles.

  1. Position controlled Knee Rehabilitation Orthotic Device for Patients after Total Knee Replacement Arthroplasty

    NASA Astrophysics Data System (ADS)

    Wannaphan, Patsiri; Chanthasopeephan, Teeranoot

    2016-11-01

    Knee rehabilitation after total knee replacement arthroplasty is essential for patients during their post-surgery recovery period. This study is about designing one degree of freedom knee rehabilitation equipment to assist patients for their post-surgery exercise. The equipment is designed to be used in sitting position with flexion/extension of knee in sagittal plane. The range of knee joint motion is starting from 0 to 90 degrees angle for knee rehabilitation motion. The feature includes adjustable link for different human proportions and the torque feedback control at knee joint during rehabilitation and the control of flexion/extension speed. The motion of the rehabilitation equipment was set to move at low speed (18 degrees/sec) for knee rehabilitation. The rehabilitation link without additional load took one second to move from vertical hanging up to 90° while the corresponding torque increased from 0 Nm to 2 Nm at 90°. When extra load is added, the link took 1.5 seconds to move to 90° The torque is then increased from 0 Nm to 4 Nm. After a period of time, the speed of the motion can be varied. User can adjust the motion to 40 degrees/sec during recovery activity of the knee and users can increase the level of exercise or motion up to 60 degrees/sec to strengthen the muscles during throughout their rehabilitation program depends on each patient. Torque control is included to prevent injury. Patients can use the equipment for home exercise to help reduce the number of hospital visit while the patients can receive an appropriate therapy for their knee recovery program.

  2. Computational Poromechanics of Human Knee Joint

    NASA Astrophysics Data System (ADS)

    Kazemi, Mojtaba; Li, LePing

    2012-02-01

    Extensive computer modeling has been performed in the recent decade to investigate the mechanical response of the healthy and repaired knee joints. Articular cartilages and menisci have been commonly modeled as single-phase elastic materials in the previous 3D simulations. A comprehensive study considering the interplay of the collagen fibers and fluid pressurization in the tissues in situ remains challenging. We have developed a 3D model of the human knee accounting for the mechanical function of collagen fibers and fluid flow in the cartilages and menisci. An anatomically accurate structure of the human knee was used for this purpose including bones, articular cartilages, menisci and ligaments. The fluid pressurization in the femoral cartilage and menisci under combined creep loading was investigated. Numerical results showed that fluid flow and pressure in the tissues played an important role in the mechanical response of the knee joint. The load transfer in the joint was clearly seen when the fluid pressure was considered.

  3. Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study.

    PubMed

    Wentink, E C; Koopman, H F J M; Stramigioli, S; Rietman, J S; Veltink, P H

    2013-06-01

    Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.

  4. Knee Bracing: What Works?

    MedlinePlus

    ... that make knee braces claim that their products work well. Scientific studies have not completely agreed. It's not clear what the knee braces actually do. Braces often work better in the laboratory than they do in ...

  5. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  6. Preventing Knee Injuries

    MedlinePlus

    ... as a result of a twisting or pivoting motion. This injury may cause susceptibility to repeat injuries and knee instability, and therefore often requires surgery. Occasionally, a twisting or hyperextension force to the knee may result in a tibial ...

  7. Knee arthroscopy - discharge

    MedlinePlus

    ... remove it. Torn or damaged anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) Inflamed or damaged ... surgery Knee pain Meniscal allograft transplantation Patient Instructions ACL reconstruction - discharge Getting your home ready - knee or ...

  8. Microprocessor prosthetic knees.

    PubMed

    Berry, Dale

    2006-02-01

    This article traces the development of microprocessor prosthetic knees from early research in the 1970s to the present. Read about how microprocessor knees work, functional options, patient selection, and the future of this prosthetic.

  9. Knee braces - unloading

    MedlinePlus

    ... in their knees, they are referring to a type of arthritis called osteoarthritis . Osteoarthritis is caused by wear and tear inside your knee joints. Cartilage, the firm, rubbery tissue that cushions all of ...

  10. Reliability and sensitivity of a simple isometric posterior lower limb muscle test in professional football players.

    PubMed

    McCall, Alan; Nedelec, Mathieu; Carling, Christopher; Le Gall, Franck; Berthoin, Serge; Dupont, Gregory

    2015-01-01

    This study aimed (1) to determine the reliability of a simple and quick test to assess isometric posterior lower limb muscle force in professional football players and (2) verify its sensitivity to detect reductions in force following a competitive match. Twenty-nine professional football players performed a 3-s maximal isometric contraction of the posterior lower limb muscles for both legs with players lying supine. Both legs were tested using a knee angle of 90° and 30° measured on a force plate. Players were tested twice with one week between sessions to verify reliability. Sensitivity was tested following a full competitive football match. The test showed high reliability for dominant leg at 90° (CV = 4.3%, ICC = 0.95, ES = 0.15), non-dominant leg at 90° (CV = 5.4%, ICC = 0.95, ES = 0.14), and non-dominant leg at 30° (CV = 4.8%, ICC = 0.93, ES = 0.30) and good reliability for dominant leg at 30° (CV = 6.3%, ICC = 0.86, ES = 0.05). The measure was sensitive enough to detect reductions in force for dominant leg at 90° (P = 0.0006, ES > 1), non-dominant leg at 90° (P = 0.0142, ES = 1), and non-dominant leg at 30° (P = 0.0064, ES > 1) and for dominant leg at 30° (P = 0.0016, ES > 1). In conclusion, the present test represents a useful and practical field tool to determine the magnitude of match-induced fatigue of the posterior lower limb muscles and potentially to track their recovery.

  11. Total knee replacement plus physical and medical therapy or treatment with physical and medical therapy alone: a randomised controlled trial in patients with knee osteoarthritis (the MEDIC-study)

    PubMed Central

    2012-01-01

    Background There is a lack of high quality evidence concerning the efficacy of total knee arthroplasty (TKA). According to international evidence-based guidelines, treatment of knee osteoarthritis (KOA) should include patient education, exercise and weight loss. Insoles and pharmacological treatment can be included as supplementary treatments. If the combination of these non-surgical treatment modalities is ineffective, TKA may be indicated. The purpose of this randomised controlled trial is to examine whether TKA provides further improvement in pain, function and quality of life in addition to optimised non-surgical treatment in patients with KOA defined as definite radiographic OA and up to moderate pain. Methods/Design The study will be conducted in The North Denmark Region. 100 participants with radiographic KOA (K-L grade ≥2) and mean pain during the previous week of ≤ 60 mm (0–100, best to worst scale) who are considered eligible for TKA by an orthopaedic surgeon will be included. The treatment will consist of 12 weeks of optimised non-surgical treatment consisting of patient education, exercise, diet, insoles, analgesics and/or NSAIDs. Patients will be randomised to either receiving or not receiving a TKA in addition to the optimised non-surgical treatment. The primary outcome will be the change from baseline to 12 months on the Knee Injury and Osteoarthritis Outcome Score (KOOS)4 defined as the average score for the subscale scores for pain, symptoms, activities of daily living, and quality of life. Secondary outcomes include the five individual KOOS subscale scores, EQ-5D, pain on a 100 mm Visual Analogue Scale, self-efficacy, pain pressure thresholds, and isometric knee flexion and knee extension strength. Discussion This is the first randomised controlled trial to investigate the efficacy of TKA as an adjunct treatment to optimised non-surgical treatment in patients with KOA. The results will significantly contribute to evidence

  12. Examining the knee joint.

    PubMed

    Monk, Daniel

    2013-04-01

    Appropriate history taking and examination can ensure accurate diagnosis of common knee problems, and rapid and effective interventions or referral to orthopaedic specialists. This article describes the anatomy of the knee joint and discusses relevant history taking, the examination process, special tests and radiology, as well as common knee injuries and their management.

  13. Knee disarticulation after total-knee replacement.

    PubMed

    Lambregts, S A M; Hitters, W M G C

    2002-12-01

    An 89-year-old woman who had a total-knee replacement in the past, underwent a knee disarticulation of the same leg because of an ischaemic foot. Eight (8) months postoperatively the stump is fully weight-bearing and the patient is able to walk safely, using a prosthesis and a walking frame.

  14. Knee Lymphocutaneous Fistula Secondary to Knee Arthroplasty

    PubMed Central

    Pérez-de la Fuente, T.; Sandoval, E.; Alonso-Burgos, A.; García-Pardo, L.; Cárcamo, C.; Caballero, O.

    2014-01-01

    Lower limb lymphorrhea secondary to a surgical procedure is a rare but difficult-to-solve complication. In lower limb, this entity is frequently associated with vascular procedures around the inguinal area. We report on a case of a knee lymphocutaneous fistula secondary to a knee revision arthroplasty. To our knowledge, no previous reports regarding this complication have been published. PMID:25580333

  15. Post-traumatic knee stiffness: surgical techniques.

    PubMed

    Pujol, N; Boisrenoult, P; Beaufils, P

    2015-02-01

    Post-traumatic knee stiffness and loss of range of motion is a common complication of injuries to the knee area. The causes of post-traumatic knee stiffness can be divided into flexion contractures, extension contractures, and combined contractures. Post-traumatic stiffness can be due to the presence of dense intra-articular adhesions and/or fibrotic transformation of peri-articular structures. Various open and arthroscopic surgical treatments are possible. A precise diagnosis and understanding of the pathology is mandatory prior to any surgical treatment. Failure is imminent if all pathologies are not addressed correctly. From a general point of view, a flexion contracture is due to posterior adhesions and/or anterior impingement. On the other hand, extension contractures are due to anterior adhesions and/or posterior impingement. This overview will describe the different modern surgical techniques for treating post-traumatic knee stiffness. Any bony impingements must be treated before soft tissue release is performed. Intra-articular stiff knees with a loss of flexion can be treated by an anterior arthroscopic arthrolysis. Extra-articular pathology causing a flexion contracture can be treated by open or endoscopic quadriceps release. Extension contractures can be treated by arthroscopic or open posterior arthrolysis. Postoperative care (analgesia, rehabilitation) is essential to maintaining the range of motion obtained intra-operatively.

  16. HINGED CAST BRACE FOR PERSISTENT FLEXION CONTRACTURE FOLLOWING TOTAL KNEE REPLACEMENT

    PubMed Central

    Karam, Matthew D; Pugely, Andrew; Callaghan, John J; Shurr, Donald

    2011-01-01

    The reported incidence of persistent knee flexion contracture following total knee arthroplasty (TKA) has varied from 1-15 percent Various treatment modalities have been described in attempts to manage this often difficult problem. This paper describes a novel method of treatment by using a hinged cast brace (previously reported for treatment of femur fractures and knee contractures secondary to hemophilia and cerebral palsy) for use in patients with symptomatic knee flexion contractures. Application of this cast brace with frequent adjustment (every three to four days, initially) toward full extension can often improve knee extension, after physical therapy and other modalities such as extension-assist braces have failed. Care must be taken in the application and use of this device which utilizes frequent manipulations to reduce and maintain the knee flexion angle. We report two clinical cases in which this protocol was effectively used in decreasing symptomatic knee flexion contractures. PMID:22096423

  17. A new method to measure post-traumatic joint contractures in the rabbit knee.

    PubMed

    Hildebrand, Kevin A; Holmberg, Michael; Shrive, Nigel

    2003-12-01

    A new device and method to measure rabbit knee joint angles are described. The method was used to measure rabbit knee joint angles in normal specimens and in knee joints with obvious contractures. The custom-designed and manufactured gripping device has two clamps. The femoral clamp sits on a pinion gear that is driven by a rack attached to a materials testing system. A 100 N load cell in series with the rack gives force feedback. The tibial clamp is attached to a rotatory potentiometer. The system allows the knee joint multiple degrees-of-freedom (DOF). There are two independent DOF (compression-distraction and internal-external rotation) and two coupled motions (medial-lateral translation coupled with varus-valgus rotation; anterior-posterior translation coupled with flexion-extension rotation). Knee joint extension-flexion motion is measured, which is a combination of the materials testing system displacement (converted to degrees of motion) and the potentiometer values (calibrated to degrees). Internal frictional forces were determined to be at maximum 2% of measured loading. Two separate experiments were performed to evaluate rabbit knees. First, normal right and left pairs of knees from four New Zealand White (NZW) rabbits were subjected to cyclic loading. An extension torque of 0.2 Nm was applied to each knee. The average change in knee joint extension from the first to the fifth cycle was 1.9 deg +/- 1.5 deg (mean +/- sd) with a total of 49 tests of these eight knees. The maximum extension of the four left knees (tested 23 times) was 14.6 deg +/- 7.1 deg, and of the four right knees (tested 26 times) was 12.0 deg +/- 10.9 deg. There was no significant difference in the maximum extension between normal left and right knees. In the second experiment, nine skeletally mature NZW rabbits had stable fractures of the femoral condyles of the right knee that were immobilized for five, six or 10 weeks. The left knee served as an unoperated control. Loss of knee joint

  18. Reduced Maximal Force during Acute Anterior Knee Pain Is Associated with Deficits in Voluntary Muscle Activation

    PubMed Central

    Salomoni, Sauro; Tucker, Kylie; Hug, François; McPhee, Megan; Hodges, Paul

    2016-01-01

    Although maximal voluntary contraction (MVC) force is reduced during pain, studies using interpolated twitch show no consistent reduction of voluntary muscle drive. The present study aimed to test if the reduction in MVC force during acute experimental pain could be explained by increased activation of antagonist muscles, weak voluntary activation at baseline, or changes in force direction. Twenty-two healthy volunteers performed maximal voluntary isometric knee extensions before, during, and after the effects of hypertonic (pain) and isotonic (control) saline injections into the infrapatellar fat pad. The MVC force, voluntary activation, electromyographic (EMG) activity of agonist, antagonist, and auxiliary (hip) muscles, and pain cognition and anxiety scores were recorded. MVC force was 9.3% lower during pain than baseline (p < 0.001), but there was no systematic change in voluntary activation. Reduced MVC force during pain was variable between participants (SD: 14%), and was correlated with reduced voluntary activation (r = 0.90), baseline voluntary activation (r = − 0.62), and reduced EMG amplitude of agonist and antagonist muscles (all r > 0.52), but not with changes in force direction, pain or anxiety scores. Hence, reduced MVC force during acute pain was mainly explained by deficits in maximal voluntary drive. PMID:27559737

  19. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  20. In vivo determination of total knee arthroplasty kinematics

    SciTech Connect

    Komistek, Richard D; Mahfouz, Mohamed R; Bertin, Kim; Rosenberg, Aaron; Kennedy, William

    2008-01-01

    The objective of this study was to determine if consistent posterior femoral rollback of an asymmetrical posterior cruciate retaining (PCR) total knee arthroplasty was mostly influenced by the implant design, surgical technique, or presence of a well-functioning posterior cruciate ligament (PCL). Three-dimensional femorotibial kinematics was determined for 80 subjects implanted by 3 surgeons, and each subject was evaluated under fluoroscopic surveillance during a deep knee bend. All subjects in this present study having an intact PCL had a well-functioning PCR knee and experienced normal kinematic patterns, although less in magnitude than the normal knee. In addition, a surprising finding was that, on average, subjects without a PCL still achieved posterior femoral rollback from full extension to maximum knee flexion. The findings in this study revealed that implant design did contribute to the normal kinematics demonstrated by subjects having this asymmetrical PCR total knee arthroplasty.

  1. Functional status of the articularis genus muscle in individuals with knee osteoarthritis

    PubMed Central

    Saito, A.; Okada, K.; Saito, I.; Kinoshita, K.; Seto, A.; Takahashi, Y.; Shibata, K.; Sato, H.; Wakasa, M.

    2016-01-01

    Objectives: To clarify the functional status of the articularis genus muscle (AGM) in individuals with knee osteoarthritis (OA) and to analyze the muscle’s relationship with knee OA. Methods: Fifty-two individuals with knee OA (mean age, 73.4 years), 50 elderly individuals without knee OA changes (mean age, 71.2 years) and 75 young individuals (mean age, 20.2 years) were observed the AGM using ultrasonography. The thickness of the AGM, the anteroposterior distance of the suprapatellar bursa, and moving distance of the muscle insertion were measured both at rest and during isometric contraction, and values during contraction were expressed as percentages of the values at rest (%Muscle-Increase, %Bursa-Increase). Results: Muscle thickness at rest, %Muscle-Increase, %Bursa-Increase, and moving distance of the muscle insertion were significantly lower and anteroposterior distance of the suprapatellar bursa was significantly higher in the OA group than in the controls (p < 0.001, all). In the OA group, these values for the AGM were significantly correlated with knee range of motion, knee pain, and Kellgren and Lawrence grade. Conclusions: Individuals with knee OA exhibited atrophic changes and dysfunctions of the AGM, and these were associated with symptoms. Atrophic changes and dysfunctions of the AGM may be specific changes associated with knee OA. PMID:27973387

  2. Time Course of Central and Peripheral Alterations after Isometric Neuromuscular Electrical Stimulation-Induced Muscle Damage

    PubMed Central

    Fouré, Alexandre; Nosaka, Kazunori; Wegrzyk, Jennifer; Duhamel, Guillaume; Le Troter, Arnaud; Boudinet, Hélène; Mattei, Jean-Pierre; Vilmen, Christophe; Jubeau, Marc; Bendahan, David; Gondin, Julien

    2014-01-01

    Isometric contractions induced by neuromuscular electrostimulation (NMES) have been shown to result in a prolonged force decrease but the time course of the potential central and peripheral factors have never been investigated. This study examined the specific time course of central and peripheral factors after isometric NMES-induced muscle damage. Twenty-five young healthy men were subjected to an NMES exercise consisting of 40 contractions for both legs. Changes in maximal voluntary contraction force of the knee extensors (MVC), peak evoked force during double stimulations at 10 Hz (Db10) and 100 Hz (Db100), its ratio (10∶100), voluntary activation, muscle soreness and plasma creatine kinase activity were assessed before, immediately after and throughout four days after NMES session. Changes in knee extensors volume and T2 relaxation time were also assessed at two (D2) and four (D4) days post-exercise. MVC decreased by 29% immediately after NMES session and was still 19% lower than the baseline value at D4. The decrease in Db10 was higher than in Db100 immediately and one day post-exercise resulting in a decrease (−12%) in the 10∶100 ratio. On the contrary, voluntary activation significantly decreased at D2 (−5%) and was still depressed at D4 (−5%). Muscle soreness and plasma creatine kinase activity increased after NMES and peaked at D2 and D4, respectively. T2 was also increased at D2 (6%) and D4 (9%). Additionally, changes in MVC and peripheral factors (e.g., Db100) were correlated on the full recovery period, while a significant correlation was found between changes in MVC and VA only from D2 to D4. The decrease in MVC recorded immediately after the NMES session was mainly due to peripheral changes while both central and peripheral contributions were involved in the prolonged force reduction. Interestingly, the chronological events differ from what has been reported so far for voluntary exercise-induced muscle damage. PMID:25215511

  3. Highly conforming polyethylene inlays reduce the in vivo variability of knee joint kinematics after total knee arthroplasty.

    PubMed

    Daniilidis, Kiriakos; Skwara, Adrian; Vieth, Volker; Fuchs-Winkelmann, Susanne; Heindel, Walter; Stückmann, Volker; Tibesku, Carsten O

    2012-08-01

    The use of highly conforming polyethylene inlays in total knee arthroplasty (TKA) provides improved anteroposterior stability. The aim of this fluoroscopic study was to investigate the in vivo kinematics during unloaded and loaded active extension with a highly conforming inlay and a flat inlay after cruciate retaining (CR) total knee arthroplasty (TKA). Thirty one patients (50 knees) received a fixed-bearing cruciate retaining total knee arthroplasty (Genesis II, Smith & Nephew, Schenefeld, Germany) for primary knee osteoarthritis. Twenty two of them received a flat polyethylene inlay (PE), nine a deep dished PE and 19 were in the control group (physiological knees). The mean age at the time of surgery was 62 years. Dynamic examination with fluoroscopy was performed to assess the "patella tendon angle" in relation to the knee flexion angle (measure of anteroposterior translation) and the "kinematic index" (measure of reproducibility). Fluoroscopy was performed under active extension and flexion, during unloaded movement, and under full weight bearing, simulated by step climbing. No significant difference was observed between both types of polyethylene inlay designs and the physiological knee during unloaded movement. Anteroposterior (AP) instability was found during weight-bearing movement. The deep-dish inlay resulted in lower AP translation and a non-physiological rollback. Neither inlay types could restore physiological kinematics of the knee. Despite the fact that deep dished inlays reduce the AP translation, centralisation of contact pressure results in non-physiological rollback. The influence of kinematic pattern variability on clinical results warrants further investigation.

  4. Folded isometric deformations and banana-shaped seedpod.

    PubMed

    Couturier, Etienne

    2016-08-01

    Thin vegetal shells have recently been a significant source of inspiration for the design of smart materials and soft actuators. Herein is presented a novel analytical family of isometric deformations with a family of θ-folds crossing a family of parallel z-folds; it contains the isometric deformations of a banana-shaped surface inspired by a seedpod, which converts a vertical closing into either an horizontal closing or an opening depending on the location of the fold. Similarly to the seedpod, optimum shapes for opening ease are the most elongated ones.

  5. Folded isometric deformations and banana-shaped seedpod

    NASA Astrophysics Data System (ADS)

    Couturier, Etienne

    2016-08-01

    Thin vegetal shells have recently been a significant source of inspiration for the design of smart materials and soft actuators. Herein is presented a novel analytical family of isometric deformations with a family of θ-folds crossing a family of parallel z-folds; it contains the isometric deformations of a banana-shaped surface inspired by a seedpod, which converts a vertical closing into either an horizontal closing or an opening depending on the location of the fold. Similarly to the seedpod, optimum shapes for opening ease are the most elongated ones.

  6. Evaluation of total knee mechanics using a crouching simulator with a synthetic knee substitute.

    PubMed

    Lowry, Michael; Rosenbaum, Heather; Walker, Peter S

    2016-05-01

    Mechanical evaluation of total knees is frequently required for aspects such as wear, strength, kinematics, contact areas, and force transmission. In order to carry out such tests, we developed a crouching simulator, based on the Oxford-type machine, with novel features including a synthetic knee including ligaments. The instrumentation and data processing methods enabled the determination of contact area locations and interface forces and moments, for a full flexion-extension cycle. To demonstrate the use of the simulator, we carried out a comparison of two different total knee designs, cruciate retaining and substituting. The first part of the study describes the simulator design and the methodology for testing the knees without requiring cadaveric knee specimens. The degrees of freedom of the anatomic hip and ankle joints were reproduced. Flexion-extension was obtained by changing quadriceps length, while variable hamstring forces were applied using springs. The knee joint was represented by three-dimensional printed blocks on to which the total knee components were fixed. Pretensioned elastomeric bands of realistic stiffnesses passed through holes in the block at anatomical locations to represent ligaments. Motion capture of the knees during flexion, together with laser scanning and computer modeling, was used to reconstruct contact areas on the bearing surfaces. A method was also developed for measuring tibial component interface forces and moments as a comparative assessment of fixation. The method involved interposing Tekscan pads at locations on the interface. Overall, the crouching machine and the methodology could be used for many different mechanical measurements of total knee designs, adapted especially for comparative or parametric studies.

  7. Electromyography of superficial and deep neck muscles during isometric, voluntary, and reflex contractions.

    PubMed

    Siegmund, Gunter P; Blouin, Jean-Sébastien; Brault, John R; Hedenstierna, Sofia; Inglis, J Timothy

    2007-02-01

    Increasingly complex models of the neck neuromusculature need detailed muscle and kinematic data for proper validation. The goal of this study was to measure the electromyographic activity of superficial and deep neck muscles during tasks involving isometric, voluntary, and reflexively evoked contractions of the neck muscles. Three male subjects (28-41 years) had electromyographic (EMG) fine wires inserted into the left sternocleidomastoid, levator scapulae, trapezius, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles. Surface electrodes were placed over the left sternohyoid muscle. Subjects then performed: (i) maximal voluntary contractions (MVCs) in the eight directions (45 deg intervals) from the neutral posture; (ii) 50 N isometric contractions with a slow sweep of the force direction through 720 deg; (iii) voluntary oscillatory head movements in flexion and extension; and (iv) initially relaxed reflex muscle activations to a forward acceleration while seated on a sled. Isometric contractions were performed against an overhead load cell and movement dynamics were measured using six-axis accelerometry on the head and torso. In all three subjects, the two anterior neck muscles had similar preferred activation directions and acted synergistically in both dynamic tasks. With the exception of splenius capitis, the posterior and posterolateral neck muscles also showed consistent activation directions and acted synergistically during the voluntary motions, but not during the sled perturbations. These findings suggest that the common numerical-modeling assumption that all anterior muscles act synergistically as flexors is reasonable, but that the related assumption that all posterior muscles act synergistically as extensors is not. Despite the small number of subjects, the data presented here can be used to inform and validate a neck model at three levels of increasing neuromuscular-kinematic complexity: muscles generating forces

  8. 32. ISOMETRIC VIEW OF PIPING PLAN, SHOWING PATH OF CONDUIT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. ISOMETRIC VIEW OF PIPING PLAN, SHOWING PATH OF CONDUIT FROM CONTROL BUNKER TO SHIELDING TANK. F.C. TORKELSON DRAWING NUMBER 842-ARVFS-701-P-1. INEL INDEX CODE NUMBER: 075 0701 60 851 151977. - Idaho National Engineering Laboratory, Advanced Reentry Vehicle Fusing System, Scoville, Butte County, ID

  9. Near Isometric Biomass Partitioning in Forest Ecosystems of China

    PubMed Central

    Hui, Dafeng; Wang, Jun; Shen, Weijun; Le, Xuan; Ganter, Philip; Ren, Hai

    2014-01-01

    Based on the isometric hypothesis, belowground plant biomass (MB) should scale isometrically with aboveground biomass (MA) and the scaling exponent should not vary with environmental factors. We tested this hypothesis using a large forest biomass database collected in China. Allometric scaling functions relating MB and MA were developed for the entire database and for different groups based on tree age, diameter at breast height, height, latitude, longitude or elevation. To investigate whether the scaling exponent is independent of these biotic and abiotic factors, we analyzed the relationship between the scaling exponent and these factors. Overall MB was significantly related to MA with a scaling exponent of 0.964. The scaling exponent of the allometric function did not vary with tree age, density, latitude, or longitude, but varied with diameter at breast height, height, and elevation. The mean of the scaling exponent over all groups was 0.986. Among 57 scaling relationships developed, 26 of the scaling exponents were not significantly different from 1. Our results generally support the isometric hypothesis. MB scaled near isometrically with MA and the scaling exponent did not vary with tree age, density, latitude, or longitude, but increased with tree size and elevation. While fitting a single allometric scaling relationship may be adequate, the estimation of MB from MA could be improved with size-specific scaling relationships. PMID:24466149

  10. Monitoring elbow isometric contraction by novel wearable fabric sensing device

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Tao, Xiaoming; So, Raymond C. H.; Shu, Lin; Yang, Bao; Li, Ying

    2016-12-01

    Fabric-based wearable technology is highly desirable in sports, as it is light, flexible, soft, and comfortable with little interference to normal sport activities. It can provide accurate information on the in situ deformation of muscles in a continuous and wireless manner. During elbow flexion in isometric contraction, upper arm circumference increases with the contraction of elbow flexors, and it is possible to monitor the muscles’ contraction by limb circumferential strains. This paper presents a new wireless wearable anthropometric monitoring device made from fabric strain sensors for the human upper arm. The materials, structural design and calibration of the device are presented. Using an isokinetic testing system (Biodex3®) and the fabric monitoring device simultaneously, in situ measurements were carried out on elbow flexors in isometric contraction mode with ten subjects for a set of positions. Correlations between the measured values of limb circumferential strain and normalized torque were examined, and a linear relationship was found during isometric contraction. The average correlation coefficient between them is 0.938 ± 0.050. This wearable anthropometric device thus provides a useful index, the limb circumferential strain, for upper arm muscle contraction in isometric mode.

  11. Make No Bones about It: Long Bones Scale Isometrically.

    PubMed

    Sedwick, Caitlin

    2015-08-01

    Long bones are far from being simple cylinders, so how is the relative positioning of their various features maintained during growth? A new study shows that growth is isometric and that drift from the correct position is minimized. Read the Research Article.

  12. Probing disorder in isometric pyrochlore and related complex oxides

    NASA Astrophysics Data System (ADS)

    Shamblin, Jacob; Feygenson, Mikhail; Neuefeind, Joerg; Tracy, Cameron L.; Zhang, Fuxiang; Finkeldei, Sarah; Bosbach, Dirk; Zhou, Haidong; Ewing, Rodney C.; Lang, Maik

    2016-05-01

    There has been an increased focus on understanding the energetics of structures with unconventional ordering (for example, correlated disorder that is heterogeneous across different length scales). In particular, compounds with the isometric pyrochlore structure, A2B2O7, can adopt a disordered, isometric fluorite-type structure, (A, B)4O7, under extreme conditions. Despite the importance of the disordering process there exists only a limited understanding of the role of local ordering on the energy landscape. We have used neutron total scattering to show that disordered fluorite (induced intrinsically by composition/stoichiometry or at far-from-equilibrium conditions produced by high-energy radiation) consists of a local orthorhombic structural unit that is repeated by a pseudo-translational symmetry, such that orthorhombic and isometric arrays coexist at different length scales. We also show that inversion in isometric spinel occurs by a similar process. This insight provides a new basis for understanding order-to-disorder transformations important for applications such as plutonium immobilization, fast ion conduction, and thermal barrier coatings.

  13. Probing disorder in isometric pyrochlore and related complex oxides.

    PubMed

    Shamblin, Jacob; Feygenson, Mikhail; Neuefeind, Joerg; Tracy, Cameron L; Zhang, Fuxiang; Finkeldei, Sarah; Bosbach, Dirk; Zhou, Haidong; Ewing, Rodney C; Lang, Maik

    2016-05-01

    There has been an increased focus on understanding the energetics of structures with unconventional ordering (for example, correlated disorder that is heterogeneous across different length scales). In particular, compounds with the isometric pyrochlore structure, A2B2O7, can adopt a disordered, isometric fluorite-type structure, (A, B)4O7, under extreme conditions. Despite the importance of the disordering process there exists only a limited understanding of the role of local ordering on the energy landscape. We have used neutron total scattering to show that disordered fluorite (induced intrinsically by composition/stoichiometry or at far-from-equilibrium conditions produced by high-energy radiation) consists of a local orthorhombic structural unit that is repeated by a pseudo-translational symmetry, such that orthorhombic and isometric arrays coexist at different length scales. We also show that inversion in isometric spinel occurs by a similar process. This insight provides a new basis for understanding order-to-disorder transformations important for applications such as plutonium immobilization, fast ion conduction, and thermal barrier coatings.

  14. 11. Historic American Buildings Survey, PHOTOCOPY OF ISOMETRIC PORTION OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Historic American Buildings Survey, PHOTOCOPY OF ISOMETRIC PORTION OF J.M. WHITAKER'S SURVEY OF THE LIPPITT MILL, SHEET NO. 15912 DATED MARCH 22, 1913. Blue line ozalid print in the collection of the Department of Civil and Mechanical Engineering, Museum of History and Technology, the Smithsonian Institution. - Lippitt Mill, 825 Main Street, West Warwick, Kent County, RI

  15. Cooling Does Not Affect Knee Proprioception

    PubMed Central

    Ozmun, John C.; Thieme, Heather A.; Ingersoll, Christopher D.; Knight, Kenneth L.

    1996-01-01

    The effect of cooling on proprioception of the knee has not been studied extensively. In this study, we investigated the movement reproduction (timing and accuracy) aspect of proprioception. Subjects were tested under two conditions: a 20-minute application of ice and control. Proprioceptive accuracy and timing were measured by passively moving the knee, then comparing the subject's active reproduction of the passive movement. Subjects were blindfolded, then tested in three sectors of the knee's range of motion: 90° to 60°, 60° to 30°, and 30° to full extension. Ice application had no apparent effect on the subject's ability to perform accurate movement reproductions in the sectors tested. However, accuracy of the subject's final angle reproduction varied between the sectors as did the total time of the movement. One possible explanation for the difference between sectors is that different receptors are active at different points in the knee's range of motion. We conclude that cooling the knee joint for 20 minutes does not have an adverse effect on proprioception. PMID:16558379

  16. Cooling does not affect knee proprioception.

    PubMed

    Ozmun, J C; Thieme, H A; Ingersoll, C D; Knight, K L

    1996-01-01

    The effect of cooling on proprioception of the knee has not been studied extensively. In this study, we investigated the movement reproduction (timing and accuracy) aspect of proprioception. Subjects were tested under two conditions: a 20-minute application of ice and control. Proprioceptive accuracy and timing were measured by passively moving the knee, then comparing the subject's active reproduction of the passive movement. Subjects were blindfolded, then tested in three sectors of the knee's range of motion: 90 degrees to 60 degrees , 60 degrees to 30 degrees , and 30 degrees to full extension. Ice application had no apparent effect on the subject's ability to perform accurate movement reproductions in the sectors tested. However, accuracy of the subject's final angle reproduction varied between the sectors as did the total time of the movement. One possible explanation for the difference between sectors is that different receptors are active at different points in the knee's range of motion. We conclude that cooling the knee joint for 20 minutes does not have an adverse effect on proprioception.

  17. Portfolio theory of optimal isometric force production: Variability predictions and nonequilibrium fluctuation dissipation theorem

    NASA Astrophysics Data System (ADS)

    Frank, T. D.; Patanarapeelert, K.; Beek, P. J.

    2008-05-01

    We derive a fundamental relationship between the mean and the variability of isometric force. The relationship arises from an optimal collection of active motor units such that the force variability assumes a minimum (optimal isometric force). The relationship is shown to be independent of the explicit motor unit properties and of the dynamical features of isometric force production. A constant coefficient of variation in the asymptotic regime and a nonequilibrium fluctuation-dissipation theorem for optimal isometric force are predicted.

  18. Insulin and glucose responses during bed rest with isotonic and isometric exercise

    NASA Technical Reports Server (NTRS)

    Dolkas, C. B.; Greenleaf, J. E.

    1977-01-01

    The effects of daily intensive isotonic (68% maximum oxygen uptake) and isometric (21% maximum extension force) leg exercise on plasma insulin and glucose responses to an oral glucose tolerance test (OGTT) during 14-day bed-rest (BR) periods were investigated in seven young healthy men. The OGTT was given during ambulatory control and on day 10 of the no-exercise, isotonic, and isometric exercise BR periods during the 15-wk study. The subjects were placed on a controlled diet starting 10 days before each BR period. During BR, basal plasma glucose concentration remained unchanged with no exercise, but increased (P less 0.05) to 87-89 mg/100 ml with both exercise regimens on day 2, and then fell slightly below control levels on day 13. The fall in glucose content during BR was independent of the exercise regimen and was an adjustment for the loss of plasma volume. The intensity of the responses of insulin and glucose to the OGTT was inversely proportional to the total daily energy expenditure during BR. It was estimated that at least 1020 kcal/day must be provided by supplemental exercise to restore the hyperinsulinemia to control levels.

  19. Novel knee joint mechanism of transfemoral prosthesis for stair ascent.

    PubMed

    Inoue, Koh; Wada, Takahiro; Harada, Ryuchi; Tachiwana, Shinichi

    2013-06-01

    The stability of a transfemoral prosthesis when walking on flat ground has been established by recent advances in knee joint mechanisms and their control methods. It is, however, difficult for users of a transfemoral prosthesis to ascend stairs. This difficulty is mainly due to insufficient generation of extension moment around the knee joint of the prosthesis to lift the body to the next step on the staircase and prevent any unexpected flexion of the knee joint in the stance phase. Only a prosthesis with an actuator has facilitated stair ascent using a step-over-step gait (1 foot is placed per step). However, its use has issues associated with the durability, cost, maintenance, and usage environment. Therefore, the purpose of this research is to develop a novel knee joint mechanism for a prosthesis that generates an extension moment around the knee joint in the stance phase during stair ascent, without the use of any actuators. The proposed mechanism is based on the knowledge that the ground reaction force increases during the stance phase when the knee flexion occurs. Stair ascent experiments with the prosthesis showed that the proposed prosthesis can realize stair ascent without any undesirable knee flexion. In addition, the prosthesis is able to generate a positive knee joint moment power in the stance phase even without any power source.

  20. Attenuation of eccentric exercise-induced muscle damage conferred by maximal isometric contractions: a mini review

    PubMed Central

    Lima, Leonardo C. R.; Denadai, Benedito S.

    2015-01-01

    Although, beneficial in determined contexts, eccentric exercise-induced muscle damage (EIMD) might be unwanted during training regimens, competitions and daily activities. There are a vast number of studies investigating strategies to attenuate EIMD response after damaging exercise bouts. Many of them consist of performing exercises that induce EIMD, consuming supplements or using equipment that are not accessible for most people. It appears that performing maximal isometric contractions (ISOs) 2–4 days prior to damaging bouts promotes significant attenuation of EIMD symptoms that are not related to muscle function. It has been shown that the volume of ISOs, muscle length in which they are performed, and interval between them and the damaging bout influence the magnitude of this protection. In addition, it appears that this protection is not long-lived, lasting no longer than 4 days. Although no particular mechanisms for these adaptations were identified, professionals should consider applying this non-damaging stimulus before submitting their patients to unaccustomed exercised. However, it seems not to be the best option for athletes or relatively trained individuals. Future, studies should focus on establishing if ISOs protect other populations (i.e., trained individuals) or muscle groups (i.e., knee extensors) against EIMD, as well as investigate different mechanisms for ISO-induced protection. PMID:26578972

  1. Mobile Sensor Application for Kinematic Detection of the Knees

    PubMed Central

    Suputtitada, Areerat; Khovidhungij, Watcharapong

    2015-01-01

    Objective To correctly measure the knee joint angle, this study utilized a Qualisys motion capture system and also used it as the reference to assess the validity of the study's Inertial Measurement Unit (IMU) system that consisted of four IMU sensors and the Knee Angle Recorder software. The validity was evaluated by the root mean square (RMS) of different angles and the intraclass correlation coefficient (ICC) values between the Qualisys system and the IMU system. Methods Four functional knee movement tests for ten healthy participants were investigated, which were the knee flexion test, the hip and knee flexion test, the forward step test and the leg abduction test, and the walking test. Results The outcomes of the knee flexion test, the hip and knee flexion test, the forward step test, and the walking test showed that the RMS of different angles were less than 6°. The ICC values were in the range of 0.84 to 0.99. However, the leg abduction test showed a poor correlation in the measurement of the knee abduction-adduction movement. Conclusion The IMU system used in this study is a new good method to measure the knee flexion-extension movement. PMID:26361597

  2. Two-Year Incidence and Predictors of Future Knee Arthroplasty in Persons with Symptomatic Knee Osteoarthritis: Preliminary Analysis of Longitudinal Data from the Osteoarthritis Initiative

    PubMed Central

    Kong, Xiangrong; Jiranek, William A.

    2009-01-01

    Objective There is little evidence to guide physicians when discussing future likelihood of knee arthroplasty with patients who have symptomatic knee osteoarthritis. Data from Osteoarthritis Initiative (OAI) was used to determine the incidence of and predictors for knee arthroplasty. Methods OAI data were collected on a sample of 778 persons aged 45 to 79 years with symptomatic knee osteoarthritis. An extensive set of measurements were obtained at baseline and persons were followed for 2 years to identify who underwent knee arthroplasty. Random forest analysis was used to identify optimal variables that discriminate among those who did and those who did not undergo knee arthroplasty. Results The two year incidence of knee arthroplasty in the cohort was 3.7% (95%CI, 2.6%, 5.3%). Because of the low number of knee arthroplasty procedures, the predictor analysis was preliminary in nature. The analysis identified several variables that could be used to assist in identifying patients at future risk for knee arthroplasty. Conclusion For persons at high risk of knee arthroplasty, the two year incidence of knee arthroplasty is very low. The most powerful predictors were those that accounted for disease severity and functional loss. These data could assist physicians in advising patients with knee osteoarthritis on future surgical care. PMID:19419874

  3. Fatigue Effects on Knee Joint Stability During Two Jump Tasks in Women

    PubMed Central

    Ortiz, Alexis; Olson, Sharon L.; Etnyre, Bruce; Trudelle-Jackson, Elaine E.; Bartlett, William; Venegas-Rios, Heidi L.

    2010-01-01

    Dynamic knee joint stability may be affected by the onset of metabolic fatigue during sports participation that could increase the risk for knee injury. The purpose of this investigation was to determine the effects of metabolic fatigue on knee muscle activation, peak knee joint angles, and peak knee internal moments in young women during 2 jumping tasks. Fifteen women (mean age: 24.6 ± 2.6 years) participated in one nonfatigued session and one fatigued session. During both sessions, peak knee landing flexion and valgus joint angles, peak knee extension and varus/valgus internal moments, electromyographic (EMG) muscle activity of the quadriceps and hamstrings, and quadriceps/hamstring EMG cocontraction ratio were measured. The tasks consisted of a single-legged drop jump from a 40-cm box and a 20-cm, up-down, repeated hop task. The fatigued session included a Wingate anaerobic protocol followed by performance of the 2 tasks. Although participants exhibited greater knee injury–predisposing factors during the fatigued session, such as lesser knee flexion joint angles, greater knee valgus joint angles, and greater varus/valgus internal joint moments for both tasks, only knee flexion during the up-down task was statistically significant (p = 0.028). Metabolic fatigue may perhaps predispose young women to knee injuries by impairing dynamic knee joint stability. Training strength-endurance components and the ability to maintain control of body movements in either rested or fatigued situations might help reduce injuries in young women athletes. PMID:20300024

  4. Fatigue effects on knee joint stability during two jump tasks in women.

    PubMed

    Ortiz, Alexis; Olson, Sharon L; Etnyre, Bruce; Trudelle-Jackson, Elaine E; Bartlett, William; Venegas-Rios, Heidi L

    2010-04-01

    Dynamic knee joint stability may be affected by the onset of metabolic fatigue during sports participation that could increase the risk for knee injury. The purpose of this investigation was to determine the effects of metabolic fatigue on knee muscle activation, peak knee joint angles, and peak knee internal moments in young women during 2 jumping tasks. Fifteen women (mean age: 24.6 +/- 2.6 years) participated in one nonfatigued session and one fatigued session. During both sessions, peak knee landing flexion and valgus joint angles, peak knee extension and varus/valgus internal moments, electromyographic (EMG) muscle activity of the quadriceps and hamstrings, and quadriceps/hamstring EMG cocontraction ratio were measured. The tasks consisted of a single-legged drop jump from a 40-cm box and a 20-cm, up-down, repeated hop task. The fatigued session included a Wingate anaerobic protocol followed by performance of the 2 tasks. Although participants exhibited greater knee injury-predisposing factors during the fatigued session, such as lesser knee flexion joint angles, greater knee valgus joint angles, and greater varus/valgus internal joint moments for both tasks, only knee flexion during the up-down task was statistically significant (p = 0.028). Metabolic fatigue may perhaps predispose young women to knee injuries by impairing dynamic knee joint stability. Training strength-endurance components and the ability to maintain control of body movements in either rested or fatigued situations might help reduce injuries in young women athletes.

  5. Is latero-medial patellar mobility related to the range of motion of the knee joint after total knee arthroplasty?

    PubMed

    Ota, Susumu; Nakashima, Takeshi; Morisaka, Ayako; Omachi, Takaaki; Ida, Kunio; Kawamura, Morio

    2010-12-01

    Diminished range of motion (ROM) of the knee joint after total knee arthroplasty (TKA) is thought to be related to reduced patellar mobility. This has not been confirmed clinically due to a lack of quantitative methods adequate for measuring patellar mobility. We investigated the relationship between patellar mobility by a reported quantitative method and knee joint ROM after TKA. Forty-nine patients [osteoarthritis--OA: 29 knees; rheumatoid arthritis--RA: 20 knees] were examined after TKA. Respective medial and lateral patellar mobility was measured 1 and 6 months postoperatively using a patellofemoral arthrometer (PFA). Knee joint ROM was also measured in each of those 2 sessions. Although the flexion and extension of the knee joints improved significantly from 1 to 6 months after TKA, the medial and lateral patellar displacements (LPDs) failed to improve during that same period. Moreover, only the changes in knee flexion and medial patellar displacement (MPD) between the two sessions were positively correlated (r = 0.31, p < 0.05). However, our findings demonstrated that medial and lateral patellar mobility had no sufficient longitudinal relationship with knee ROM after TKA.

  6. Multiple osteochondroses of bilateral knee joints: a case report.

    PubMed

    Franceschi, Francesco; Barnaba, Simona Angela; Rojas, Mario; Gualdi, Giancarlo; Rizzello, Giacomo; Papalia, Rocco; Denaro, Vincenzo

    2007-04-01

    Knee injuries in young athletes include not only the typical adult bone injuries, ligament and cartilage, but also the growth plate lesions. Osteochondroses are idiopathic, self-limited disturbance of enchondral ossification in which a rapid growth spurt is present. The patella could be affected by two different kinds of osteochondroses: Kohler syndrome and Sinding-Larsen-Johansson. Here we are reporting the first case of simultaneous location of osteochondroses of the two ossification centers of both patella. A 9-year-old boy, competitive skater, presented a history of anterior knee pain involving both knees. Standard X-rays, axial patellar view, MRI and arthro-MR were performed. In order to follow the natural history of the pathology and the evolution of the healing, examinations at 2 years were repeated. We proposed the young skater a medical and a physiotherapeutic treatment based on unloading, isometric exercises, NSAID. As the symptoms improve a gradual return to competitive sports activity was allowed. The case mentioned above can be considered an atypical case because the patient suffered for a bilateral knee osteochondroses, involving simultaneously the primary ossification centre (Kohler syndrome) and the secondary ossification centre (Larsen syndrome) of the patella.

  7. The influence of pain on knee motion in patients with osteoarthritis undergoing total knee arthroplasty.

    PubMed

    Bennett, Damien; Hanratty, Brian; Thompson, Neville; Beverland, David E

    2009-04-01

    Pain is the predominant symptom of degenerative knee arthritis and the main reason patients undergo total knee arthroplasty (TKA). Variation in patient response to pain has proved difficult to quantify. The effect of removing pain by testing TKA patients' range of motion (ROM) before and after the administration of anesthesia has not previously been analyzed. This study objectively quantifies the effect of eliminating pain on knee joint ROM for a typical group of TKA patients with osteoarthritis. We prospectively recruited 141 patients with osteoarthritis admitted for TKA to assess the inhibitory effect of pain on ROM. Passive maximum flexion, extension, and ROM were measured preoperatively before and after administration of anesthesia (spinal anesthetic followed by femoral and sciatic regional nerve blocks). Following pain abolition, passive maximum flexion increased by an average of 13.4 degrees (SD=11.9 degrees), passive maximum extension improved by an average of 3.0 degrees (SD=4.2 degrees), and passive ROM increased by an average of 16.4 degrees (SD=13.1 degrees). The change in each parameter was statistically significant (P<.0001). Improvements in flexion (P=.01) and ROM (P=.005) were significantly greater in women. Measurements taken before anesthesia reflect knee ROM that the patient will tolerate before pain becomes the limiting factor, while measurements taken after anesthesia is achieved suggest the knee ROM possible once pain is eliminated. Abolition of pain led to significant increases in knee flexion, extension, and ROM, suggesting that pain has a significant inhibitory effect on knee motion.

  8. Patterns of knee osteoarthritis in Arabian and American knees.

    PubMed

    Hodge, W Andrew; Harman, Melinda K; Banks, Scott A

    2009-04-01

    This study illustrates differences in the cartilage degeneration in osteoarthritic knees in patients with more frequent hyperflexion activities of daily living compared with Western patients. Proximal tibial articular cartilage wear and cruciate ligament condition were assessed in Saudi Arabian and North American patients with varus osteoarthritis undergoing total knee arthroplasty. In anterior cruciate ligament (ACL) intact knees, there were significant differences in wear location, with a clearly more anterior pattern in Saudi Arabian knees. Complete ACL deficiency occurred in 25% of North American knees but only 14% of Saudi Arabian knees. These ACL-deficient knees showed the most severe cartilage wear in both groups and posterior medial wear patterns. Biomechanical descriptions of knee flexion and axial rotation during kneeling or squatting are consistent with the more pronounced anteromedial and posterolateral cartilage wear patterns observed on the Saudi Arabian knees. These observations provide insight into altered knee mechanics in 2 culturally different populations with different demands on knee flexion.

  9. Anaerobic capacity, isometric endurance, and Laser sailing performance.

    PubMed

    Vangelakoudi, A; Vogiatzis, I; Geladas, N

    2007-08-01

    Laser sailors have to tolerate fatiguing contractions of the lower-body muscles for prolonged periods. The aims of the present study were (1) to evaluate the difference between top-ranked and club sailors, in their capacity to resist fatigue during sustained isometric and maximal power exercise, and (2) to examine the relationships between the above parameters and performance on a Laser simulator and competitive racing performance according to the national ranking list. Eight Greek nationally ranked Laser sailors were compared with eight club sailors. Each sailor performed: (a) an effort to the limit of tolerance on the Laser simulator, (b) an effort to the limit of tolerance of isometric endurance for the right leg on an isokinetic dynamometer, and (c) a Wingate test of maximal lower-body anaerobic power on a cycle ergometer. In the nationally ranked sailors, isometric endurance time (mean 160 s, s = 50) and endurance time on the Laser simulator (1381 s, s = 1354) were significantly (P < 0.05) longer than in the club sailors (101 s, s = 29 and 565 s, s = 367, respectively), whereas the final minute heart rate (in both groups: 149 beats . min(-1), s = 22) and the mean arterial pressure (nationally ranked sailors: 129 mmHg, s = 16; club sailors: 120 mmHg, s = 21) on the Laser simulator were not different between groups. During the Wingate test, the nationally ranked sailors had a significantly lower index of fatigue (42%, s = 5) than the club sailors (49%, s = 6). Isometric endurance time was significantly correlated with the Wingate index of fatigue (r = -0.73; P < 0.001). The nationally ranked sailors' mean and maximal anaerobic powers were significantly correlated with their national ranking positions (r = -0.83 and -0.71, respectively). It is suggested that isometric endurance and anaerobic power are well-developed in Laser class sailors and may influence their sailing performance. Furthermore, compared with club sailors, the nationally ranked sailors are able

  10. Trunk strength and lumbar paraspinal muscle activity during isometric exercise in chronic low-back pain patients and controls.

    PubMed

    Cassisi, J E; Robinson, M E; O'Conner, P; MacMillan, M

    1993-02-01

    The purpose of this study was to describe trunk strength and lumbar paraspinal muscle activity across five angles of flexion during isometric exercise and rest in chronic low-back pain patients and control subjects. High muscle tension as measured by surface integrated electromyography is predicted by a muscle spasm model, and low muscle tension is predicted by a muscle deficiency model. Prior lumbar surgery had no affect on peak torque or maximum surface integrated electromyography data. Both groups produced greater torque and less surface integrated electromyography in more flexed positions. Chronic low-back pain patients exhibited lower peak torque and lower maximum surface integrated electromyography bilaterally during isometric extension effort across all angles. A muscle deficiency model of chronic low back pain was supported by these data and a muscle spasm model was not supported. Discriminant analyses indicated that monitoring maximum surface integrated electromyography of lumbar muscles during isometric effort facilitates classification of chronic low-back pain patients. Future directions are discussed in terms of applying psychophysiologic methods to pain rehabilitation.

  11. Patient function after a posterior stabilizing total knee arthroplasty: cam-post engagement and knee kinematics.

    PubMed

    Suggs, Jeremy F; Hanson, George R; Park, Sang Eun; Moynihan, Angela L; Li, Guoan

    2008-03-01

    Even though posterior substituting total knee arthroplasty has been widely used in surgery, how the cam-post mechanism (posterior substituting mechanism) affects knee joint kinematics and function in patients is not known. The objective of the present study was to investigate posterior femoral translation, internal tibial rotation, tibiofemoral contact, and cam-post engagement of total knee arthroplasty patients during in vivo weight-bearing flexion. Twenty-four knees with a PS TKA were investigated while performing a single leg weight-bearing lunge from full extension to maximum flexion as images were recorded using a dual fluoroscopic system. The in vivo knee position at each targeted flexion angle was reproduced using 3D TKA models and the fluoroscopic images. The kinematics of the knee was measured from the series of the total knee arthroplasty models. The cam-post engagement was determined when the surface model of the femoral cam overlapped with that of the tibial post. The mean maximum flexion angle for all the subjects was 112.5 +/- 13.1 degrees . The mean flexion angle where cam-post engagement was observed was 91.1 +/- 10.9 degrees . The femur moved anteriorly from 0 degrees to 30 degrees and posteriorly through the rest of the flexion range. The internal tibial rotation increased approximately 6 degrees from full extension to 90 degrees of flexion and decreased slightly with further flexion. Both the medial and lateral contact point moved posteriorly from 0 degrees to 30 degrees , remained relatively constant from 30 degrees to 90 degrees , and then moved further posterior from 90 degrees to maximum flexion. The in vivo cam-post engagement corresponded to increased posterior translation and reduced internal tibial rotation at high flexion of the posterior substituting total knee arthroplasty. The initial cam-post engagement was also mildly correlated with the maximum flexion angle of the knee (R = 0.51, p = 0.019). A later cam-post engagement might

  12. Interpolation function for approximating knee joint behavior in human gait

    NASA Astrophysics Data System (ADS)

    Toth-Taşcǎu, Mirela; Pater, Flavius; Stoia, Dan Ioan

    2013-10-01

    Starting from the importance of analyzing the kinematic data of the lower limb in gait movement, especially the angular variation of the knee joint, the paper propose an approximation function that can be used for processing the correlation among a multitude of knee cycles. The approximation of the raw knee data was done by Lagrange polynomial interpolation on a signal acquired using Zebris Gait Analysis System. The signal used in approximation belongs to a typical subject extracted from a lot of ten investigated subjects, but the function domain of definition belongs to the entire group. The study of the knee joint kinematics plays an important role in understanding the kinematics of the gait, this articulation having the largest range of motion in whole joints, in gait. The study does not propose to find an approximation function for the adduction-abduction movement of the knee, this being considered a residual movement comparing to the flexion-extension.

  13. Isometric exercise in the denervated heart: a Doppler echocardiographic study.

    PubMed Central

    Robson, S C; Furniss, S S; Heads, A; Boys, R J; McGregor, C; Bexton, R S

    1989-01-01

    The haemodynamic responses to isometric exercise of eight recipients of orthotopic heart transplants and eight healthy controls were studied. Each performed sustained exercise at 30% of maximal voluntary contraction for three minutes on a handgrip dynamometer. Cardiac output was measured by combined Doppler and cross sectional echocardiography before exercise and every 30 seconds during and after exercise. In the controls cardiac output and blood pressure increased significantly owing to an increase in heart rate with no change in stroke volume. In the transplant group cardiac output, heart rate, and stroke volume remained unchanged throughout exercise. In contrast with its response to dynamic exercise the denervated human heart is unable to increase cardiac output during isometric exercise. The pressor response that occurs is mediated via an increase in peripheral vascular resistance. PMID:2649119

  14. 15. "GENERAL, INSTRUMENTATION AND CONTROL SYSTEMS, ISOMETRIC." Test Area 1120. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. "GENERAL, INSTRUMENTATION AND CONTROL SYSTEMS, ISOMETRIC." Test Area 1-120. Specifications No. ENG04-353-55-72; Drawing No. 60-09-12; sheet 6 of 148; file no. 1320/57. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 4338, no change. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Leuhman Ridge near Highways 58 & 395, Boron, Kern County, CA

  15. Cervical Resistance Training: Effects on Isometric and Dynamic Strength

    DTIC Science & Technology

    2006-11-01

    report engaging in neck-specific strengthening exercises . It is generally believed that neck strengthening may result in fewer neck injuries. This study...was designed to investigate the effects of 12 wk of cervical strength training (3 d wk1) on isometric strength, dynamic strength, and hypertrophy ...for an F-16 career. Furthermore, only 26.9% of the pilots routinely performed exercises . Improvements in neck strength as a result of dynamic

  16. Exoskeletal chitin scales isometrically with body size in terrestrial insects.

    PubMed

    Lease, Hilary M; Wolf, Blair O

    2010-06-01

    The skeletal system of animals provides the support for a variety of activities and functions. For animals such as mammals, which have endoskeletons, research has shown that skeletal investment (mass) scales with body mass to the 1.1 power. In this study, we ask how exoskeletal investment in insects scales with body mass. We measured the body mass and mass of exoskeletal chitin of 551 adult terrestrial insects of 245 species, with dry masses ranging from 0.0001 to 2.41 g (0.0002-6.13 g wet mass) to assess the allometry of exoskeletal investment. Our results showed that exoskeletal chitin mass scales isometrically with dry body mass across the Insecta as M(chitin) = a M(dry) (b), where b = 1.03 +/- 0.04, indicating that both large and small terrestrial insects allocate a similar fraction of their body mass to chitin. This isometric chitin-scaling relationship was also evident at the taxonomic level of order, for all insect orders except Coleoptera. We additionally found that the relative exoskeletal chitin investment, indexed by the coefficient, a, varies with insect life history and phylogeny. Exoskeletal chitin mass tends to be proportionally less and to increase at a lower rate with mass in flying than in nonflying insects (M(flying insect chitin) = -0.56 x M(dry) (0.97); M(nonflying insect chitin) = -0.55 x M(dry) (1.03)), and to vary with insect order. Isometric scaling (b = 1) of insect exoskeletal chitin suggests that the exoskeleton in insects scales differently than support structures of most other organisms, which have a positive allometry (b > 1) (e.g., vertebrate endoskeleton, tree secondary tissue). The isometric pattern that we document here additionally suggests that exoskeletal investment may not be the primary limit on insect body size.

  17. Jumper's Knee (Patellar Tendonitis)

    MedlinePlus

    ... regularly play sports that involve a lot of repetitive jumping — like track and field (particularly high-jumping), basketball, volleyball, gymnastics, running, and soccer — can put a lot of strain on their knees. Jumper's knee can seem like a minor injury that isn't really that serious. Because of ...

  18. Tuberculosis of the knee

    PubMed Central

    Lidder, Surjit; Lang, Kathryn; Haroon, Mallick; Shahidi, Mitra; El-Guindi, Magdi

    2009-01-01

    Extrapulmonary manifestations of tuberculosis are reported in less than one in five cases with the knee affected in 8% after the spine and hip. We report a case of isolated highly erosive tuberculosis of the knee presenting in a previously fit Vietnamese woman. The difficulties of diagnosis, modalities of chemotherapeutic management, and surgical treatment are discussed. PMID:21808686

  19. Partial knee replacement

    MedlinePlus

    ... American Academy of Orthopedic Surgeons (AAOS). Treatment of osteoarthritis of the knee: Evidence-based guideline 2nd edition (summary). Rosemont, IL. ... al. American Academy of Orthopaedic Surgeons. Treatment of osteoarthritis of the knee (nonarthroplasty). J Am Acad Orthop Surg . 2009;17: ...

  20. A laterality effect in isometric and isotonic labial tracking.

    PubMed

    Sussman, H M; Westbury, J R

    1978-09-01

    Hemispheric dominance for sensorimotor control of lip activity was investigated by use of a pursuit auditory tracking task. This task involves continuous frequency matching of a computer-generated target tone and a subject-controlled cursor tone. Thirty right-handed subjects were tested under isometric lip and hand control, and 20 right-handed subjects under isotonic lip control. Subjects tracked 10 1-min trials under each laterality condition--cursor/right ear, target/left ear, and vice versa. In both experiments tracking performance was better when the lip-controlled cursor tone was presented to the right ear (hence direct contralateral route to left hemisphere). A significant (p less than 0.05) cursor/right-ear advantage was found under isometric hand-tracking. Analysis routines examined relative laterality advantages across several time intervals within each 1-min trial. Consistent lateralization scores in favor of cursor/right-ear presentations (REAs) were independent of the time interval measured. For isometric tracking, 58% of subjects having laterality advantages (p less than 0.10) revealed REAs. For isotonic tracking, 71% of subjects revealed REAs. Implications of the latter finding are discussed relative to a left hemisphere mechanism specialized to integrate movement-generated auditory feedback with dynamic kinesthetic information from the articulators.

  1. Maximum isometric lifting strengths of men in teamwork.

    PubMed

    Lee, Tzu-Hsien

    2004-01-01

    This study reexamined the additivity of maximum isometric teamwork lifting strength using experienced and height-matched young male participants. The maximum isometric lifting strength was measured for four exertion heights (45, 75, 105, and 140 cm) and four lifting styles (one-, two, three-, and four-person exertions). The results showed that actual teamwork strength could be greater or lower than the sum of individual strengths. If it was greater, the difference between the two could be either significant or nonsignificant, but if it was lower, there was no significant difference between the two. Actual teamwork strength ranged from 90.0% to 134.8% of the sum of individual strengths, indicating that experienced and height-matched participants could overcome the problem of lack of coordination in isometric teamwork lifting. The results also showed that some teamwork members, especially weaker members, might be forced to exert strengths higher than their maximum individual voluntary strengths in teamwork lifting. To avoid such overexertion in teamwork, it is recommended that the weight of the handled load be controlled and lower than the sum of all members' strengths. Additionally, members with significantly different strength abilities should not be assigned to the same team. Actual or potential applications of this research include designing member assignments in teamwork lifting tasks.

  2. Skeletal muscle transverse strain during isometric contraction at different lengths.

    PubMed

    van Donkelaar, C C; Willems, P J; Muijtjens, A M; Drost, M R

    1999-08-01

    An important assumption in 2D numerical models of skeletal muscle contraction involves deformation in the third dimension of the included muscle section. The present paper studies the often used plane strain description. Therefore, 3D muscle surface deformation is measured from marker displacements during isometric contractions at various muscle lengths. Longitudinal strains at superficial muscle fibers ( - 14 +/- 2.6% at L0, n = 57) and aponeurosis (0.8 +/- 0.9% at L0) decrease with increasing muscle length. The same holds for transverse muscle surface strains in superficial muscle fibers and aponeurosis, which are comparable at intermediate muscle length, but differ at long and short muscle length. Because transverse strains during isometric contraction change with initial muscle length, it is concluded that the effect of muscle length on muscle deformation cannot be studied in plane strain models. These results do not counteract the use of these models to study deformation in contractions with approximately - 9 % longitudinal muscle fiber strain, as transverse strain in superficial muscle fibers and in aponeurosis tissue is minimal in that case. Aponeurosis surface area change decreases with increasing initial muscle length, but muscle fiber surface area change is - 11%, independent of muscle length. Assuming incompressible muscle material, this means that strain perpendicular to the muscle surface equals 11%. Taking the relationship between transverse and longitudinal muscle fiber strain into account, it is hypothesized that superficial muscle fibers flatten during isometric contractions.

  3. Short-interval two-stage approach to primary total knee arthroplasty for acutely septic osteoarthritic knees.

    PubMed

    Hochreiter, Bettina; Strahm, Carol; Behrend, Henrik

    2016-10-01

    Treatment strategies for advanced knee osteoarthritis with coexistent joint infection are not well established. While in periprosthetic joint infection the two-stage approach has been studied extensively, only few case reports on two-stage total knee arthroplasty (TKA) for knee osteoarthritis with coexistent joint infection have been published. The purpose of this paper was to report on our method of implementing a two-stage TKA with intervening antibiotic-loaded articulating cement spacers and a short interval between first- and second-stage procedures to treat two patients with Staphylococcus aureus-infected end-stage knee osteoarthritis. Consistent infection eradication was found at a 1-year follow-up with postoperative range of motion and knee scores comparing favourably with those of other case series. Level of evidence V.

  4. Pneumatic osteoarthritis knee brace.

    PubMed

    Stamenović, Dimitrije; Kojić, Milos; Stojanović, Boban; Hunter, David

    2009-04-01

    Knee osteoarthritis is a chronic disease that necessitates long term therapeutic intervention. Biomechanical studies have demonstrated an improvement in the external adduction moment with application of a valgus knee brace. Despite being both efficacious and safe, due to their rigid frame and bulkiness, current designs of knee braces create discomfort and difficulties to patients during prolonged periods of application. Here we propose a novel design of a light osteoarthritis knee brace, which is made of soft conforming materials. Our design relies on a pneumatic leverage system, which, when pressurized, reduces the excessive loads predominantly affecting the medial compartment of the knee and eventually reverses the malalignment. Using a finite-element analysis, we show that with a moderate level of applied pressure, this pneumatic brace can, in theory, counterbalance a greater fraction of external adduction moment than the currently existing braces.

  5. Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

    PubMed Central

    Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

    2016-01-01

    Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

  6. Knee kinematics in medial osteoarthritis during in vivo weight-bearing activities.

    PubMed

    Hamai, Satoshi; Moro-oka, Taka-Aki; Miura, Hiromasa; Shimoto, Takeshi; Higaki, Hidehiko; Fregly, Benjamin J; Iwamoto, Yukihide; Banks, Scott A

    2009-12-01

    Dynamic knee kinematics were analyzed for medial osteoarthritic (OA) knees in three activities, including two types of maximum knee flexion. Continuous x-ray images of kneeling, squatting, and stair climbing motions were taken using a large flat panel detector. CT-derived bone models were used for the model registration-based 3D kinematic measurements. Three-dimensional joint kinematics and contact locations were determined using two methods: bone-fixed coordinate systems and by interrogation of CT-based bone model surfaces. The femur exhibited gradual external rotation with knee flexion for kneeling and squatting activities, and gradual internal rotation with knee extension for stair climbing. From 100 degrees to 120 degrees flexion, contact locations showed a medial pivot pattern similar to normal knees. However, knees with medial OA displayed a femoral internal rotation bias and less posterior translation when compared with normal knees. A classic screw-home movement was not observed in OA knees near extension. Decreased variability with both activities and methods of calculation were demonstrated for all three activities. In conclusion, the weight-bearing kinematics of patients with medial OA differs from normal knees. Pathological changes of the articulating surfaces and the ligaments correspond to observed abnormalities in knee kinematics.

  7. Adaptations in muscular activation of the knee extensor muscles with strength training in young and older adults.

    PubMed

    Knight, C A; Kamen, G

    2001-12-01

    The purpose of this study was to compare the extent of muscular activation during maximal voluntary knee extension contractions in old and young individuals and to examine the effects of resistance training on muscular activation in each group. The interpolated twitch technique was used to estimate muscular activation during two pre-training baseline tests, and after two and six weeks of resistance training. Throughout the study, the older group was 30% less strong than the young group (p=0.02). The training protocol was effective in both groups with overall isometric strength gains of 30 and 36% in the older (p=0.01) and young (p<0.01) groups, respectively. 10-RM training loads increased by 66% in the old group (p<0.01) and by 77% in the young group (p<0.01) throughout training. At the first baseline test, a 2% difference in muscular activation between groups (p=0.3) did not explain the large disparity in strength. Muscular activation increased by 2% in both groups throughout training (p<0.01). Despite considerably less muscular strength in the older group, muscular activation was greater than 95% of maximum and appears to be equal in both young and older individuals. Both groups demonstrated similar but small increases in muscular activation throughout training.

  8. Robotic Total Knee Arthroplasty: Surgical Assistant for a Customized Normal Kinematic Knee.

    PubMed

    Urish, Kenneth L; Conditt, Michael; Roche, Martin; Rubash, Harry E

    2016-09-01

    Although current total knee arthroplasty (TKA) is considered a highly successful surgical procedure, patients undergoing TKA can still experience substantial functional impairment and increased revision rates as compared with those undergoing total hip arthroplasty. Robotic-assisted surgery has been available clinically for almost 15 years and was developed, in part, to address these concerns. Robotic-assisted surgery aims to improve TKA by enhancing the surgeon's ability to optimize soft tissue balancing, reproduce alignment, and restore normal knee kinematics. Current systems include a robotic arm with a variety of different navigation systems with active, semi-active, or passive control. Semi-active systems have become the dominant strategy, providing a haptic window through which the surgeon consistently prepares a TKA based on preoperative planning. A review of previous designs and clinical studies demonstrates that these robotic systems decrease variability and increase precision, primarily with the mechanical axis and restoration of the joint line. Future design objectives include precise planning and consistent intraoperative execution. Preoperative planning, intraoperative sensors, augmenting surgical instrumentation, and biomimetic surfaces will be used to re-create the 4-bar linkage system in the knee. Implants will be placed so that the knee functions with a medial pivot, lateral rollback, screw home mechanism, and patellar femoral tracking. Soft tissue balancing will become more than equalizing the flexion and extension gaps and will match the kinematics to a normal knee. Together, coupled with advanced knee designs, they may be the key to a patient stating, "My knee feels like my natural knee." [Orthopedics. 2016; 39(5):e822-e827.].

  9. Tibiofemoral conformity and kinematics of rotating-bearing knee prostheses.

    PubMed

    D'Lima, D D; Trice, M; Urquhart, A G; Colwell, C W

    2001-05-01

    Increasing tibiofemoral articular conformity theoretically increases articular contact area and reduces contact stresses in total knee arthroplasty. Fixed-bearing knee designs possess relatively low tibiofemoral conformity, in part to allow tibiofemoral rotation without generating excessive stresses at the articulation or the implant-bone interface. This study analyzed knee kinematics of mobile-bearing designs in a closed chain dynamic knee extension model in posterior cruciate-retaining design with high- and low tibiofemoral conformity and posterior cruciate-substituting designs with and without rotational constraint. Overall, for all conditions, the mobile-bearing insert rotated with the femur in the presence of tibiofemoral axial rotation. In addition, the correlation of bearing rotation with femoral rotation was stronger for the high-conformity and rotationally-constrained designs than for the low-conformity designs and strongest for the posterior cruciate-retaining high-conformity condition. Changes in conformity or rotational constraint did not appear to affect femoral roll back, tibiofemoral axial rotation, or varus-valgus angulation. The results suggest that mobile-bearing inserts rotate with the femur and increasing conformity or rotational constraint in mobile-bearing design knee prostheses does not affect knee kinematics adversely, at least under closed chain knee extension conditions in vitro.

  10. Patient Self-Assessed Passive Range of Motion of the Knee Cannot Replace Health Professional Measurements.

    PubMed

    Borgbjerg, Jens; Madsen, Frank; Odgaard, Anders

    2017-03-01

    The purpose of this study was to investigate whether patients can accurately self-assess their knee passive range of motion (PROM). A picture-based questionnaire for patient self-assessment of knee PROM was developed and posted to patients. The self-assessed PROM from 58 patients was compared with surgeon-assessed PROM using a short-arm goniometer. Agreement between the measurement methods was calculated with the Bland-Altman method. We calculated the sensitivity and specificity of patient-assessed PROM in dichotomously detecting knee motion impairment in both flexion (≤ 100 degrees) and extension (≥ 10-degree flexion contracture). Surgeon- and patient-assessed knee PROM showed a mean difference (95% limits of agreement) of -2.1 degrees (-42.5 to 38.3 degrees) for flexion and -8.1 degrees (-28.8 to 12.7 degrees) for extension. The sensitivity of patient self-assessed PROM in identifying knee flexion and extension impairments was 86 and 100%, respectively, whereas its specificity was 84 and 43%, respectively. Although wide limits of agreement were observed between surgeon- and patient-assessed knee PROM, the picture-based questionnaire for patient assessment of knee ROM was found to be a valid tool for dichotomously detecting knee motion impairment in flexion (≤ 100 degrees). However, the specificity of the questionnaire for detection of knee extension impairments (≥ 10-degree flexion contracture) was low, which limits is practical utility for this purpose.

  11. Hip Strength Deficits in People With Symptomatic Knee Osteoarthritis: A Systematic Review With Meta-analysis.

    PubMed

    Deasy, Margaret; Leahy, Edmund; Semciw, Adam Ivan

    2016-08-01

    Study Design Systematic review with meta-analysis. Background A complete understanding of impairments associated with knee osteoarthritis would optimize exercise interventions for people with knee osteoarthritis. Our current understanding of hip strength deficits in this population is based on studies with conflicting findings and small samples. There is a need to systematically review and pool current evidence. Objectives To determine whether hip strength deficits exist in people with symptomatic knee osteoarthritis. Methods Electronic databases (MEDLINE, CINAHL, Embase, the Cochrane Library, and PsycINFO) were searched through February 2016. Studies comparing hip strength in people diagnosed with symptomatic knee osteoarthritis to healthy control participants were included in the review. A meta-analysis with random effects was applied to relevant data from included studies and a modified Grading of Recommendations Assessment, Development and Evaluation approach was used to evaluate the quality of evidence for each pooled analysis. Results Five studies were included in the review. Meta-analysis revealed moderate-quality evidence of weaker isometric and isokinetic hip abduction strength in people with knee osteoarthritis (moderate difference: 7% to 24% weaker) and very low-quality evidence of no difference in isometric hip adduction strength. There was very low- to moderate-quality evidence of weaker isokinetic hip strength in the remaining planes of motion (moderate to large differences: 14% to 55% weaker). Conclusion Significant hip strength deficits exist in people with knee osteoarthritis. Hip strength assessment should be considered in clinical practice and may assist with directing targeted management strategies. Level of Evidence Symptom prevalence, level 1a-. J Orthop Sports PhysTher 2016;46(8):629-639. Epub3 Jul 2016. doi:10.2519/jospt.2016.6618.

  12. Total Knee Arthroplasty in Patients with Blount Disease or Blount-Like Deformity.

    PubMed

    Natoli, Roman M; Nypaver, Chrissy M; Schiff, Adam P; Hopkinson, William J; Rees, Harold W

    2016-01-01

    Blount disease is associated with complex deformity of the proximal tibia, and some patients will develop knee osteoarthritis. Five patients (eight knees) with Blount disease or Blount-like deformity underwent total knee arthroplasty. Mean proximal tibial metaphyseal-diaphyseal angle was 20.75°. Each patient had substantial posteromedial tibial bony defects and six knees required extensive medial releases. Two knees required increased constraint at index procedure. One patient has undergone bilateral revision surgery with rotating hinge prostheses. Mean WOMAC scores were 13.5 and Knee Society scores were 212.5 at average 75.2 month follow-up. Despite technical challenges, patients with these deformities can have successful outcomes after total knee arthroplasty. Surgeons should be prepared to address posteromedial tibial bony defects and consider constrained arthroplasty at the index procedure.

  13. Advanced concepts in knee arthrodesis

    PubMed Central

    Wood, Jennifer H; Conway, Janet D

    2015-01-01

    The aim is to describe advanced strategies that can be used to diagnose and treat complications after knee arthrodesis and to describe temporary knee arthrodesis to treat infected knee arthroplasty. Potential difficult complications include nonunited knee arthrodesis, limb length discrepancy after knee arthrodesis, and united but infected knee arthrodesis. If a nonunited knee arthrodesis shows evidence of implant loosening or failure, then bone grafting the nonunion site as well as exchange intramedullary nailing and/or supplemental plate fixation are recommended. If symptomatic limb length discrepancy cannot be satisfactorily treated with a shoe lift, then the patient should undergo tibial lengthening over nail with a monolateral fixator or exchange nailing with a femoral internal lengthening device. If a united knee arthrodesis is infected, the nail must be removed. Then the surgeon has the option of replacing it with a long, antibiotic cement-coated nail. The authors also describe temporary knee arthrodesis for infected knee arthroplasty in patients who have the potential to undergo insertion of a new implant. The procedure has two goals: eradication of infection and stabilization of the knee. A temporary knee fusion can be accomplished by inserting both an antibiotic cement-coated knee fusion nail and a static antibiotic cement-coated spacer. These advanced techniques can be helpful when treating difficult complications after knee arthrodesis and treating cases of infected knee arthroplasty. PMID:25793160

  14. Effect of toe extension on EMG of triceps surae muscles during isometric dorsiflexion.

    PubMed

    Siddiqi, Ariba; Arjunan, Sridhar P; Kumar, Dinesh

    2016-12-01

    The protocol for estimating force of contraction by triceps surae (TS) muscles requires the immobilization of the ankle during dorsiflexion and plantar flexion. However, large variability in the results has been observed. To identify the cause of this variability, experiments were conducted where ankle dorsiflexion force and electromyogram (EMG) of the TS were recorded under two conditions: (i) toes were strapped and (ii) toes were unstrapped, with all other conditions such as immobilization of the ankle remaining unchanged. The root mean square (RMS) of the EMG and the force were analyzed and one-tail Student's t-test was performed for significance between the two conditions. The RMS of the EMG from TS muscles was found to be significantly higher (~55%) during dorsiflexion with toes unstrapped compared with when the toes were strapped. The torque corresponding to dorsiflexion was also higher with toes unstrapped. Our study has shown that it is important to strap the toes when measuring the torque at the ankle and EMG of the TS muscles.

  15. Knee Proprioception and Strength and Landing Kinematics During a Single-Leg Stop-Jump Task

    PubMed Central

    Nagai, Takashi; Sell, Timothy C; House, Anthony J; Abt, John P; Lephart, Scott M

    2013-01-01

    Context The importance of the sensorimotor system in maintaining a stable knee joint has been recognized. As individual entities, knee-joint proprioception, landing kinematics, and knee muscles play important roles in functional joint stability. Preventing knee injuries during dynamic tasks requires accurate proprioceptive information and adequate muscular strength. Few investigators have evaluated the relationship between knee proprioception and strength and landing kinematics. Objective To examine the relationship between knee proprioception and strength and landing kinematics. Design Cross-sectional study. Setting University research laboratory. Patients or Other Participants Fifty physically active men (age = 26.4 ± 5.8 years, height = 176.5 ± 8.0 cm, mass = 79.8 ± 16.6 kg). Intervention(s) Three tests were performed. Knee conscious proprioception was evaluated via threshold to detect passive motion (TTDPM). Knee strength was evaluated with a dynamometer. A 3-dimensional biomechanical analysis of a single-legged stop-jump task was used to calculate initial contact (IC) knee-flexion angle and knee-flexion excursion. Main Outcome Measure(s) The TTDPM toward knee flexion and extension, peak knee flexion and extension torque, and IC knee-flexion angle and knee flexion excursion. Linear correlation and stepwise multiple linear regression analyses were used to evaluate the relationships of both proprioception and strength against landing kinematics. The α level was set a priori at .05. Results Enhanced TTDPM and greater knee strength were positively correlated with greater IC knee-flexion angle (r range = 0.281–0.479, P range = .001–.048). The regression analysis revealed that 27.4% of the variance in IC knee-flexion angle could be accounted for by knee-flexion peak torque and TTDPM toward flexion (P = .001). Conclusions The current research highlighted the relationship between knee proprioception and strength and landing kinematics. Individuals with enhanced

  16. The Effects of a Prophylactic Knee Brace and Two Neoprene Knee Sleeves on the Performance of Healthy Athletes: A Crossover Randomized Controlled Trial

    PubMed Central

    Mortaza, Niyousha; Ebrahimi, Ismail; Jamshidi, Ali Ashraf; Abdollah, Vahid; Kamali, Mohammad; Abas, Wan Abu Bakar Wan; Osman, Noor Azuan Abu

    2012-01-01

    Knee injury is one of the major problems in sports medicine, and the use of prophylactic knee braces is an attempt to reduce the occurrence and/or severity of injuries to the knee joint ligament(s) without inhibiting knee mobility. The aim of the present study was to examine the effect of one recently designed prophylactic knee brace and two neoprene knee sleeves upon performance of healthy athletes. Thirty-one healthy male athletes (age = 21.2±1.5) volunteered as participants to examine the effect of prophylactic knee brace/sleeves on performance using isokinetic and functional tests. All subjects were tested in four conditions in a random order: 1. nonbraced (control) 2. using a neoprene knee sleeve 3. using a knee sleeve with four bilateral metal supports and 4. using a prophylactic knee brace. The study design was a crossover, randomized, controlled trial. Subjects completed single leg vertical jump, cross-over hop, and the isokinetic knee flexion and extension (at 60, 180, 300°/sec). Data were collected from the above tests and analyzed for jump height, cross-over hop distance, peak torque to body weight ratio and average power, respectively. Comparisons of these variables in the four testing conditions revealed no statistically significant difference (p>0.05). The selected prophylactic brace/sleeves did not significantly inhibit athletic performance which might verify that their structure and design have caused no complication in the normal function of the knee joint. Moreover, it could be speculated that, if the brace or the sleeves had any limiting effect, our young healthy athletic subjects were well able to generate a mean peak torque large enough to overcome this possible restriction. Further studies are suggested to investigate the long term effect of these prophylactic knee brace and sleeves as well as their possible effect on the adjacent joints to the knee. PMID:23185549

  17. The effects of a prophylactic knee brace and two neoprene knee sleeves on the performance of healthy athletes: a crossover randomized controlled trial.

    PubMed

    Mortaza, Niyousha; Ebrahimi, Ismail; Jamshidi, Ali Ashraf; Abdollah, Vahid; Kamali, Mohammad; Abas, Wan Abu Bakar Wan; Osman, Noor Azuan Abu

    2012-01-01

    Knee injury is one of the major problems in sports medicine, and the use of prophylactic knee braces is an attempt to reduce the occurrence and/or severity of injuries to the knee joint ligament(s) without inhibiting knee mobility. The aim of the present study was to examine the effect of one recently designed prophylactic knee brace and two neoprene knee sleeves upon performance of healthy athletes. Thirty-one healthy male athletes (age = 21.2 ± 1.5) volunteered as participants to examine the effect of prophylactic knee brace/sleeves on performance using isokinetic and functional tests. All subjects were tested in four conditions in a random order: 1. nonbraced (control) 2. using a neoprene knee sleeve 3. using a knee sleeve with four bilateral metal supports and 4. using a prophylactic knee brace. The study design was a crossover, randomized, controlled trial. Subjects completed single leg vertical jump, cross-over hop, and the isokinetic knee flexion and extension (at 60, 180, 300°/sec). Data were collected from the above tests and analyzed for jump height, cross-over hop distance, peak torque to body weight ratio and average power, respectively. Comparisons of these variables in the four testing conditions revealed no statistically significant difference (p>0.05). The selected prophylactic brace/sleeves did not significantly inhibit athletic performance which might verify that their structure and design have caused no complication in the normal function of the knee joint. Moreover, it could be speculated that, if the brace or the sleeves had any limiting effect, our young healthy athletic subjects were well able to generate a mean peak torque large enough to overcome this possible restriction. Further studies are suggested to investigate the long term effect of these prophylactic knee brace and sleeves as well as their possible effect on the adjacent joints to the knee.

  18. Probing disorder in isometric pyrochlore and related complex oxides

    DOE PAGES

    Shamblin, Jacob; Feygenson, Mikhail; Neuefeind, Joerg C; ...

    2016-02-29

    There has been an increased focus on understanding the energetics of structures that can accommodate unconventional ordering (e.g., disordered periodic arrays that appear at different length-scales). For example, the isometric pyrochlore structure, A2B2O7, forms a disordered, defect fluorite-structure, (A,B)4O7, or an aperiodic array, when exposed to extreme conditions]. The ability to accommodate disorder in its structure accounts for the tendency of some compositions to resist becoming aperiodic in high radiation fields or at high temperatures. Thus, these materials find application as host materials for immobilizing actinides, such as plutonium, fast ion conductors in solid oxide fuel cells, and thermal barriermore » coatings for gas turbine jet engines. Despite the importance of the disordering process, there has been only a limited understanding of the role of local ordering on the energetic landscape, mainly due to the use of techniques (i.e., X-ray/electron diffraction) that can only characterize the average structure over a large number unit cells and are insensitive to disorder on the oxygen sublattice. We have used neutron pair distribution functions (PDFs) to show that the disordered fluorite structure consists of a locally-ordered, orthorhombic structural unit that is repeated by a pseudo-translational symmetry, such that the ordered, orthorhombic and disordered, isometric arrays coexist at different length-scales. This disordering mechanism is a more general phenomenon in complex oxides, as PDF analysis has revealed that inversion in the isometric spinel structure, AB2O4 B(AB)O4, occurs by a similar process across the highly randomized B-site. This insight into order-disorder transformations induced intrinsically (chemical composition) or extrinsically (far from equilibrium conditions by high radiation fields) provides a new basis for understanding how modulated structures and correlated disorder at different length-scales affects the physical and

  19. Knee Conditioning Program

    MedlinePlus

    ... muscles help your knee joint absorb shock. Flexibility: Stretching the muscles that you strengthen is important for restoring range of motion and preventing injury. Gently stretching after strengthening exercises can help reduce muscle soreness ...

  20. Anterior knee pain

    MedlinePlus

    ... places extra stress on the kneecap (such as running, jumping or twisting, skiing, or playing soccer). You ... noticeable with: Deep knee bends Going down stairs Running downhill Standing up after sitting for awhile

  1. Prosthetic Knee Systems

    MedlinePlus

    ... must give support when people stand, allow smooth motion when people walk, and permit movement when people ... of knees and their options for stability and motion control would work best for them. There are ...

  2. Knee microfracture surgery

    MedlinePlus

    ... WM, Griesser MJ, Parker RD. Patellofemoral pain. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic ... ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 105. Miller RH, Azar FM. Knee injuries. In: Canale ST, ...

  3. Runners knee (image)

    MedlinePlus

    ... forces on the knee, such as a misaligned patella. Chondromalacia is treated with rest or immobilization and nonsteroidal anti-inflammatory drugs for pain. Physical therapy, especially ... alignment of the patella that cannot be corrected with therapy.

  4. Dashboard (in the) Knee

    PubMed Central

    Qureshi, AA; Green, TP

    2015-01-01

    We present the case of a 19-year-old individual presenting to an orthopaedic outpatient clinic several months following a dashboard knee injury during a road traffic accident with intermittent mechanical symptoms. Despite unremarkable examination findings and normal magnetic resonance imaging, the patient was identified subsequently as having an intra-articular plastic foreign body consistent with a piece of dashboard on arthroscopic knee assessment, the retrieval of which resulted in a complete resolution of symptoms. PMID:25723676

  5. Effectiveness of the 1RM estimation method based on isometric squat using a back-dynamometer.

    PubMed

    Demura, Shinich; Miyaguchi, Kazuyoshi; Shin, Sohee; Uchida, Yu

    2010-10-01

    This study aimed to clarify the relationships between isometric squat (IS) using a back dynamometer and 1 repetition maximum (1RM) squat for maximum force and muscle activities and to examine the effectiveness of a 1RM estimation method based on IS. The subjects were 15 young men with weight training experience (mean age 20.7 ± 0.8 years, mean height 171.3 ± 4.4 cm, mean weight 64.4 ± 8.4 kg). They performed the IS with various stance widths and squat depths. The measured data of exerted maximum force and the action potential of the agonist muscles were compared with the 1RM squat data. The exerted maximum force during IS was significantly larger in wide stance (140% shoulder width) than in narrow stance (5-cm width). The maximum force was significantly larger with decreased knee flexion. As for muscle activity, the % root mean square value of muscle electric potential of the rectus femoris and the vastus lateralis tended to be higher in wide stance. As for exerted maximum force, wide stance and parallel depth in IS showed a significant and high correlation (r = 0.73) with 1RM squat. Simple linear regression analysis revealed a significant estimated regression equation [Y = 0.992X + 30.3 (Y:1RM, X:IS)]. However, the standard error of an estimate value obtained by the regression equation was very large (11.19 kg). In conclusion, IS with wide stance and parallel depth may be useful for the estimation of 1RM squat. However, estimating a 1RM by IS using a back dynamometer may be difficult.

  6. Knee kinematics during walking at different speeds in people who have undergone total knee replacement.

    PubMed

    McClelland, Jodie A; Webster, Kate E; Feller, Julian A; Menz, Hylton B

    2011-06-01

    People who have undergone total knee replacement (TKR) experience difficulties in some daily activities including walking. Walking at faster speeds requires more knee flexion and may therefore present a greater challenge following TKR. The aim of this study was to compare the knee kinematics of patients following TKR and unimpaired controls during comfortable and fast walking speeds. Forty patients (22 women, 18 men) 12 months following TKR and 40 control participants (matched for age and sex) were assessed during walking at self-selected comfortable and fast speeds using three dimensional motion analysis. The group averages of spatiotemporal and peak kinematic characteristics in the sagittal, coronal and transverse movement planes were compared using univariate analysis of variance with walking speed as a co-variate. The TKR group walked with significantly reduced cadence (p < 0.001 at both speeds) and reduced stride length (p < 0.001 at both speeds), less knee flexion during stance and swing phases (p < 0.001 for both speeds) and less knee extension during stance phase (p < 0.024 for comfortable speed; p < 0.042 for fast speed). The TKR group also walked with less peak knee external rotation than controls at both speeds (p < 0.001 for both speeds). Both groups increased their velocity, cadence and stride length by a similar proportion when walking at fast speed. When walking at a faster speed, spatiotemporal gait parameters and knee motion are altered in a similar manner for both TKR patients and controls. However, at both walking speeds, TKR patients exhibit residual deficits 12 months following surgery.

  7. Measuring postural control during mini-squat posture in men with early knee osteoarthritis.

    PubMed

    Petrella, M; Gramani-Say, K; Serrão, P R M S; Lessi, G C; Barela, J A; Carvalho, R P; Mattiello, S M

    2017-02-06

    Studies have suggested a compromised postural control in individuals with knee osteoarthritis (OA) evidenced by larger and faster displacement of center of pressure (COP). However, quantification of postural control in the mini-squat posture performed by patients with early knee OA and its relation to muscle strength and self-reported symptoms have not been investigated. The main aim of this cross-sectional, observational, controlled study was to determine whether postural control in the mini-squat posture differs between individuals with early knee OA and a control group (CG) and verify the relation among knee extensor torque (KET) and self-reported physical function, stiffness and pain. Twenty four individuals with knee OA grades I and II (OAG) (mean age: 52.35±5.00) and twenty subjects without knee injuries (CG) (mean age: 51.40±8.07) participated in this study. Participants were assessed in postural control through a force plate (Bertec Mod. USA), which provided information about the anterior-posterior (AP) and medial-lateral (ML) COP displacement during the mini-squat, in isometric, concentric and eccentric knee extensor torque (KET) (90°/s) through an isokinetic dynamometer (BiodexMulti-Joint System3, Biodex Medical Incorporation, New York, NY, USA), and in self-reported symptoms through the WOMAC questionnaire. The main outcomes measured were the AP and ML COP amplitude and velocity of displacement; isometric, concentric, and eccentric KET and self-reported physical function, stiffness and pain. No significant differences were found between groups for postural control (p>0.05). Significant lower eccentric KET (p=0.01) and higher scores for the WOMAC subscales of pain (p=<0.001), stiffness (p=0.001) and physical function (p<0.001) were found for the OAG. Moderate and negative correlations were found between the AP COP amplitude of displacement and physical function (ρ=-0.40, p=0.02). Moderate and negative correlations were observed between the AP COP

  8. Exercise Alters Gait Pattern but Not Knee Load in Patients with Knee Osteoarthritis

    PubMed Central

    Lin, Yi-Jia; Chang, Chao-Chin; Chou, You-Cai

    2016-01-01

    Six female patients with bilateral medial knee OA and 6 healthy controls were recruited. Patients with knee OA received a 6-week physiotherapist-supervised and home-based exercise program. Outcome measures, including the Western Ontario and McMaster Universities Arthritis Index and Short Form-36 Health Survey as well as objective biomechanical indices were obtained at baseline and follow-up. After treatment, no significant difference was observed in the knee abductor moment (KAM), lever arm, and ground reaction force. We, however, observed significantly improved pain and physical function as well as altered gait patterns, including a higher hip flexor moment and hip extension angle with a faster walking speed. Although KAM was unchanged, patients with bilateral knee OA showed an improved walking speed and altered the gait pattern after 6 weeks of supervised exercise. This finding suggests that the exercise intervention improves proximal joint mechanics during walking and can be considered for patients with bilateral knee OA. Non-weight-bearing strengthening without external resistance combined with stretching exercise may be an option to improve pain and function in individuals with OA who cannot perform high resistance exercises owing to pain or other reasons. PMID:27725941

  9. Gravitational effects on human cardiovascular responses to isometric muscle contractions

    NASA Astrophysics Data System (ADS)

    Bonde-Petersen, Flemmig; Suzuki, Yoji; Sadamoto, Tomoko

    Isometric exercise induces profound cardiovascular adaptations increasing mean arterial pressure and heart rate. We investigated effects of simulated +Gz and -Gz respectively on the central and peripheral cardiovascular system. Sustained handgrip exercise was performed at 40% of maximum for 2 minutes in five subjects. This maneuver increased mean arterial pressure by 40-45 mm Hg both during head out water immersion which simulates weightlessness, as well as bedrest during -25, 0, and +25 degrees tilt from the horizontal. Lower body negative pressure (-60 mm Hg for 10 min) attenuated the response to handgrip exercise to 30 mm Hg. It also increased the heart rate minimally by about 20 beats per minute while the water immersion, as well as head up, head down and horizontal bedrest showed increments of about 50 beats per min. It was concluded that the response to isometric contraction is mediated through the high pressure baroreceptors, because similar responses were seen during stresses producing a wide variation in central venous pressure. During lower body negative pressure the increased sympathetic nervous activity itself increased resting heart rate and mean arterial pressure. The responses to static exercise were, therefore, weaker.

  10. Q-angle in patellofemoral pain: relationship with dynamic knee valgus, hip abductor torque, pain and function☆

    PubMed Central

    Almeida, Gabriel Peixoto Leão; Silva, Ana Paula de Moura Campos Carvalho e; França, Fábio Jorge Renovato; Magalhães, Maurício Oliveira; Burke, Thomaz Nogueira; Marques, Amélia Pasqual

    2016-01-01

    Objective To investigate the relationship between the q-angle and anterior knee pain severity, functional capacity, dynamic knee valgus and hip abductor torque in women with patellofemoral pain syndrome (PFPS). Methods This study included 22 women with PFPS. The q-angle was assessed using goniometry: the participants were positioned in dorsal decubitus with the knee and hip extended, and the hip and foot in neutral rotation. Anterior knee pain severity was assessed using a visual analog scale, and functional capacity was assessed using the anterior knee pain scale. Dynamic valgus was evaluated using the frontal plane projection angle (FPPA) of the knee, which was recorded using a digital camera during step down, and hip abductor peak torque was recorded using a handheld dynamometer. Results The q-angle did not present any significant correlation with severity of knee pain (r = −0.29; p = 0.19), functional capacity (r = −0.08; p = 0.72), FPPA (r = −0.28; p = 0.19) or isometric peak torque of the abductor muscles (r = −0.21; p = 0.35). Conclusion The q-angle did not present any relationship with pain intensity, functional capacity, FPPA, or hip abductor peak torque in the patients with PFPS. PMID:27069887

  11. Evaluation of potentially modifiable physical factors as predictors of health status in knee osteoarthritis patients referred for physical therapy.

    PubMed

    Gonçalves, Rui Soles; Pinheiro, João Páscoa; Cabri, Jan

    2012-08-01

    The purpose of this cross sectional study was to estimate the contributions of potentially modifiable physical factors to variations in perceived health status in knee osteoarthritis (OA) patients referred for physical therapy. Health status was measured by three questionnaires: Knee injury and Osteoarthritis Outcome Score (KOOS); Knee Outcome Survey - Activities of Daily Living Scale (KOS-ADLS); and Medical Outcomes Study - 36 item Short Form (SF-36). Physical factors were measured by a battery of tests: body mass index (BMI); visual analog scale (VAS) of pain intensity; isometric dynamometry; universal goniometry; step test (ST); timed "up and go" test (TUGT); 20-meter walk test (20MWT); and 6-minute walk test (6MWT). All tests were administered to 136 subjects with symptomatic knee OA (94 females, 42 males; age: 67.2 ± 7.1 years). Multiple stepwise regression analyses revealed that knee muscle strength, VAS of pain intensity, 6MWT, degree of knee flexion and BMI were moderate predictors of health status. In the final models, selected combinations of these potentially modifiable physical factors explained 22% to 37% of the variance in KOOS subscale scores, 40% of the variance in the KOS-ADLS scale score, and 21% to 34% of the variance in physical health SF-36 subscale scores. More research is required in order to evaluate whether therapeutic interventions targeting these potentially modifiable physical factors would improve health status in knee OA patients.

  12. Knee osteoarthritis image registration: data from the Osteoarthritis Initiative

    NASA Astrophysics Data System (ADS)

    Galván-Tejada, Jorge I.; Celaya-Padilla, José M.; Treviño, Victor; Tamez-Peña, José G.

    2015-03-01

    Knee osteoarthritis is a very common disease, in early stages, changes in joint structures are shown, some of the most common symptoms are; formation of osteophytes, cartilage degradation and joint space reduction, among others. Based on a joint space reduction measurement, Kellgren-Lawrence grading scale, is a very extensive used tool to asses radiological OA knee x-ray images, based on information obtained from these assessments, the objective of this work is to correlate the Kellgren-Lawrence score to the bilateral asymmetry between knees. Using public data from the Osteoarthritis initiative (OAI), a set of images with different Kellgren-Lawrencescores were used to determine a relationship of Kellgren-Lawrence score and the bilateral asymmetry, in order to measure the asymmetry between the knees, the right knee was registered to match the left knee, then a series of similarity metrics, mutual information, correlation, and mean squared error where computed to correlate the deformation (mismatch) of the knees to the Kellgren-Lawrence score. Radiological information was evaluated and scored by OAI radiologist groups. The results of the study suggest an association between Radiological Kellgren-Lawrence score and image registration metrics, mutual information and correlation is higher in the early stages, and mean squared error is higher in advanced stages. This association can be helpful to develop a computer aided grading tool.

  13. Explosive Strength of the Knee Extensors: The Influence of Criterion Trial Detection Methodology on Measurement Reproducibility.

    PubMed

    Dirnberger, Johannes; Wiesinger, Hans-Peter; Wiemer, Nicolas; Kösters, Alexander; Müller, Erich

    2016-04-01

    The present study was conducted to assess test-retest reproducibility of explosive strength measurements during single-joint isometric knee extension using the IsoMed 2000 dynamometer. Thirty-one physically active male subjects (mean age: 23.7 years) were measured on two occasions separated by 48-72 h. The intraclass correlation coefficient (ICC 2,1) and the coefficient of variation (CV) were calculated for (i) maximum torque (MVC), (ii) the peak rate of torque development (RTDpeak) as well as for (iii) the average rate of torque development (RTD) and the impulse taken at several predefined time intervals (0-30 to 0-300 ms); thereby explosive strength variables were derived in two conceptually different versions: on the one hand from the MVC-trial (version I), on the other hand from the trial showing the RTDpeak (version II). High ICC-values (0.80-0.99) and acceptable CV-values (1.9-8.7%) could be found for MVC as well as for the RTD and the impulse taken at time intervals of ≥100 ms, regardless of whether version I or II was used. In contrast, measurements of the RTDpeak as well as the RTD and the impulse taken during the very early contraction phase (i.e. RTD/impulse0-30ms and RTD/impulse0-50ms) showed clearly weaker reproducibility results (ICC: 0.53-0.84; CV: 7.3-16.4%) and gave rise to considerable doubts as to clinical usefulness, especially when derived using version I. However, if there is a need to measure explosive strength for earlier time intervals in practice, it is, in view of stronger reproducibility results, recommended to concentrate on measures derived from version II, which is based on the RTDpeak-trial.

  14. Extensor tendon ruptures after total knee arthroplasty.

    PubMed

    Bonnin, M; Lustig, S; Huten, D

    2016-02-01

    Extensor tendon rupture is a rare but serious complication after total knee arthroplasty (TKA) that impairs active knee extension, thereby severely affecting knee function. Surgery is usually required. Surgical options range from simple suturing to allograft reconstruction of the entire extensor mechanism and include intermediate methods such as reconstruction using neighbouring tendons or muscles, synthetic ligament implantation, and partial allograft repair. Simple suturing carries a high failure rate and should therefore be routinely combined with tissue augmentation using a neighbouring tendon or a synthetic ligament. After allograft reconstruction, outcomes are variable and long-term complications common. Salvage procedures for managing the most severe cases after allograft failure involve reconstruction using gastrocnemius or vastus flaps. Regardless of the technique used, suturing must be performed under tension, with the knee fully extended, and rehabilitation must be conducted with great caution. Weaknesses of available case-series studies include small sample sizes, heterogeneity, and inadequate follow-up duration. All treatment options are associated with substantial failure rates. The patient should be informed of this fact and plans made for a salvage option. Here, the main techniques and their outcomes are discussed, and a therapeutic strategy is suggested.

  15. NAVIGATION IN TOTAL KNEE ARTHROPLASTY

    PubMed Central

    da Mota e Albuquerque, Roberto Freire

    2015-01-01

    Navigation was the most significant advance in instrumentation for total knee arthroplasty over the last decade. It provides surgeons with a precision tool for carrying out surgery, with the possibility of intraoperative simulation and objective control over various anatomical and surgical parameters and references. Since the first systems, which were basically used to control the alignment of bone cutting referenced to the mechanical axis of the lower limb, many other surgical steps have been incorporated, such as component rotation, ligament balancing and arranging the symmetry of flexion and extension spaces, among others. Its efficacy as a precision tool with an effective capacity for promoting better alignment of the lower-limb axis has been widely proven in the literature, but the real value of optimized alignment and the impact of navigation on clinical results and the longevity of arthroplasty have yet to be established. PMID:27026979

  16. Adjustable bracing technique for the prevention of knee flexion contracture during tibial lengthening.

    PubMed

    Segev, Eitan; Hayek, Shlomo

    2003-01-01

    The authors present a simple thigh-knee brace that prevents flexion contracture during tibial lengthening. The brace is strapped to the thigh and connected to the Ilizarov frame via two simple hinges. While in the brace the knee can be mobilized for physiotherapy and locked in extension during rest.

  17. Knee joint kinematics, fixation and function related to joint area design in total knee arthroplasty.

    PubMed

    Uvehammer, J

    2001-02-01

    The aim was to study the influence of different designs of the joint area on tibial component fixation, kinematics and clinical outcome after a cemented total knee arthroplasty (TKA). The HSS score and a special questionnaire were used at the clinical examination. Conventional radiography was done to record the positioning of the implants and development of radiolucencies. The migration and inducible displacement were evaluated using radiostereometry (RSA). The kinematics of the knee during active extension was studied using dynamic RSA. In randomised and prospective studies 87 knees in 83 patients (28 male, 55 female, age 69, range 50-83) received an AMK (DePuy, Johnson & Johnson) TKA. The patients were divided into two groups. In group 1 the patients had varus/valgus deformities of < or = 5 degrees and the PCL was retained. The PCL was resected in group 2 where the patients had deformities exceeding 5 degrees and/or fixed flexion deformities of more than 10 degrees. In group 1 a flat (F, n = 20) or a concave (C, n = 20) design was implanted (study 3). In group 2 (study 4) the patients received a concave (n = 25) or a posterior-stabilised (PS, n = 22) tibial plateau. The migration of the tibial component, positioning of the prosthesis, development of radiolucencies and the clinical outcome was evaluated after 1 and 2 years. Twenty-two patients (11 F, 11 C) in group 1 (study 1) and 22 knees in 20 patients in group 2 (study 2, 11 C, 11 PS) were examined 1 year post-operatively to evaluate the kinematics of the knee. Eleven normals served as controls. During active extension of the knee the inducible displacements of the tibial component were recorded in 16 knees (15 patients). Based on successful RSA examinations 5 knees (4 F, 1 C) from group 1 and 11 knees (5 C, 6 PS) from group 2 were selected (study 5). Abnormal kinematics and especially increased AP translations compared to normals (p < 0.0005) were recorded in all designs. The concave design showed the widest

  18. The effect of gluteus medius strengthening on the knee joint function score and pain in meniscal surgery patients

    PubMed Central

    Kim, Eun-Kyung

    2016-01-01

    [Purpose] The purpose of this study was to analyze the effect of gluteus medius activity strengthening due to squat with isometric hip adduction and hip abduction in side-lying exercise on knee joint function index and pain in meniscal surgery patients. [Subjects and Methods] This study selected sample of 26 patients who had meniscal surgery more than 4 weeks ago. The patients were divided into squat with isometric hip adduction exercise group I (n=8), hip abduction in side-lying exercise group II (n=9), and combined exercise group III. The lysholm score was used to evaluate knee joint function and visual analog scale was used to evaluate pain index of knee joint. [Results] Two-way repeated measures ANOVA was used to analyze the lysholm score and visual analog scale and showed significant interaction between the groups and durations. [Conclusion] Strengthening vastus medialis oblique and gluteus medius improved functional recovery and pain reduction of knee joint in meniscal injury surgery patients. Gluteus medius strengthening exercise is essential to meniscal injury surgery patients and should be included in rehabilitation program in early stages to be conducted systematically. PMID:27821928

  19. Effects of isometric hip movements on electromyographic activities of the trunk muscles during plank exercises.

    PubMed

    Kang, Min-Hyeok; Kim, Soo-Yong; Kang, Myoung-Joo; Yoon, So-Hee; Oh, Jae-Seop

    2016-08-01

    [Purpose] The purpose of this study was to investigate the effect of isometric hip adduction and abduction on trunk muscle activity during plank exercises. [Subjects and Methods] Nineteen healthy male subjects were recruited for this study. All subjects performed the traditional plank exercise (TP), plank exercise with isometric hip adduction (PHAD), and plank exercise with isometric hip abduction (PHAB) by using an elastic band. Electromyographic (EMG) activities of the internal oblique (IO) and external oblique (EO) were measured during the 3 plank exercises by using an Electromyography system. [Results] Internal oblique and external oblique muscle activities were significantly greater during plank exercise with isometric hip adduction and plank exercise with isometric hip abduction than during traditional plank exercise. Internal oblique and external oblique muscle activities did not differ between the plank exercise with isometric hip adduction and plank exercise with isometric hip abduction conditions. [Conclusion] These findings demonstrate that loaded isometric hip movements may be a useful strategy to increase trunk muscle activity during plank exercises.

  20. [Assessment of the coronary circulation regulation by means of the so-called isometric contraction index].

    PubMed

    Urbaszek, W; Löwe, H R; Rentsch, W; Pankau, H; Günther, K

    1976-08-01

    The index of isometric contraction formed from the quotient period of isometric contraction in the erect position by period of isometric contraction in lying position gives the possibility to separate between cardially sufficient and cardially insufficient patients with adequately disturbed regulation of the cardiac circulation. The recognition of early stages of the disturbed left-ventricular function is possible. The use of an adequate exact technique in gaining the primary data is to be presumed. Corrections of the frequency of the index of isometric contraction do not improve the evidence. In the borderline region of the index of isometric contraction with values between 1.03 and 1.1 in questionable cases a further differentiation into still normal or already latent insufficient will do by the analysis of the trend of the index of isometric contraction after the application of medicaments. The determination of the change of the direction of the index of isometric contraction after peroral application of nitroglycerin would be justifiable in routine work after the recognition of the initiaction increases in patients with latent heart insufficiency, in patients with a healthy heart it decreases. The clinical value of the index of isometric contraction as a simple test of the circulatory function is highly to be estimated.

  1. Effects of isometric hip movements on electromyographic activities of the trunk muscles during plank exercises

    PubMed Central

    Kang, Min-Hyeok; Kim, Soo-Yong; Kang, Myoung-Joo; Yoon, So-Hee; Oh, Jae-Seop

    2016-01-01

    [Purpose] The purpose of this study was to investigate the effect of isometric hip adduction and abduction on trunk muscle activity during plank exercises. [Subjects and Methods] Nineteen healthy male subjects were recruited for this study. All subjects performed the traditional plank exercise (TP), plank exercise with isometric hip adduction (PHAD), and plank exercise with isometric hip abduction (PHAB) by using an elastic band. Electromyographic (EMG) activities of the internal oblique (IO) and external oblique (EO) were measured during the 3 plank exercises by using an Electromyography system. [Results] Internal oblique and external oblique muscle activities were significantly greater during plank exercise with isometric hip adduction and plank exercise with isometric hip abduction than during traditional plank exercise. Internal oblique and external oblique muscle activities did not differ between the plank exercise with isometric hip adduction and plank exercise with isometric hip abduction conditions. [Conclusion] These findings demonstrate that loaded isometric hip movements may be a useful strategy to increase trunk muscle activity during plank exercises. PMID:27630435

  2. In Vivo Kinematics of the Anterior Cruciate Ligament Deficient Knee During Wide-Based Squat Using a 2D/3D Registration Technique.

    PubMed

    Miyaji, Takeshi; Gamada, Kazuyoshi; Kidera, Kenichi; Ikuta, Futoshi; Yoneta, Kei; Shindo, Hiroyuki; Osaki, Makoto; Yonekura, Akihiko

    2012-01-01

    Anterior cruciate ligament (ACL) deficiency increases the risk of early osteoarthritis (OA). Studies of ACL deficient knee kinematics would be important to reveal the disease process and therefore to find mechanisms which would potentially slow OA progression. The purpose of this study was to determine if in vivo kinematics of the anterior cruciate ligament deficient (ACLD) knee during a wide-based squat activity differ from kinematics of the contralateral intact knee. Thirty-three patients with a unilateral ACLD knee consented to participate in this institutional review board approved study with the contralateral intact knee serving as the control. In vivo knee kinematics during the wide-based squat were analyzed using a 2D/3D registration technique utilizing CT-based bone models and lateral fluoroscopy. Comparisons were performed using values between 0 and 100° flexion both in flexion and extension phases of the squat activity. Both the ACLD and intact knees demonstrated increasing tibial internal rotation with knee flexion, and no difference was observed in tibial rotation between the groups. The tibia in the ACLD knee was more anterior than that of the contralateral knees at 0 and 5° flexion in both phases (p < 0.05). Tibiofemoral medial contact points of the ACLD knees were more posterior than that of the contralateral knees at 5, 10 and 15° of knee flexion in the extension phase of the squat activity (p < 0.05). Tibiofemoral lateral contact points of the ACLD knees were more posterior than that of the contralateral knees at 0° flexion in the both phases (p < 0.05). The kinematics of the ACLD and contralateral intact knees were similar during the wide-based squat except at the low flexion angles. Therefore, we conclude the wide-based squat may be recommended for the ACLD knee by avoiding terminal extension.

  3. Role of gastrocnemius activation in knee joint biomechanics: gastrocnemius acts as an ACL antagonist.

    PubMed

    Adouni, M; Shirazi-Adl, A; Marouane, H

    2016-01-01

    Gastrocnemius is a premier muscle crossing the knee, but its role in knee biomechanics and on the anterior cruciate ligament (ACL) remains less clear when compared to hamstrings and quadriceps. The effect of changes in gastrocnemius force at late stance when it peaks on the knee joint response and ACL force was initially investigated using a lower extremity musculoskeletal model driven by gait kinematics-kinetics. The tibiofemoral joint under isolated isometric contraction of gastrocnemius was subsequently analyzed at different force levels and flexion angles (0°-90°). Changes in gastrocnemius force at late stance markedly influenced hamstrings forces. Gastrocnemius acted as ACL antagonist by substantially increasing its force. Simulations under isolated contraction of gastrocnemius confirmed this role at all flexion angles, in particular, at extreme knee flexion angles (0° and 90°). Constraint on varus/valgus rotations substantially decreased this effect. Although hamstrings and gastrocnemius are both knee joint flexors, they play opposite roles in respectively protecting or loading ACL. Although the quadriceps is also recognized as antagonist of ACL, at larger joint flexion and in contrast to quadriceps, activity in gastrocnemius substantially increased ACL forces (anteromedial bundle). The fact that gastrocnemius is an antagonist of ACL should help in effective prevention and management of ACL injuries.

  4. Measurement of force sense reproduction in the knee joint: application of a new dynamometric device

    PubMed Central

    Zavieh,, Minoo Khalkhali; Amirshakeri,, Bahram; Rezasoltani,, Asghar; Talebi,, Ghadam Ali; Kalantari,, Khosro Khademi; Nedaey,, Vahab; Baghban,, Alireza Akbarzadeh

    2016-01-01

    [Purpose] The aim of this study was to determine the reliability of a newly designed dynamometric device for use in frequent force producing/reproducing tasks on the knee joint. [Subjects and Methods] In this cross-sectional study (Development & Reliability), 30 young healthy males and females (age 23.4 ± 2.48 years) were selected among students of Tabriz University of Medical Sciences by simple randomized selection. The study instrument was designed to measure any isometric contraction force exerted by the knee joint flexor/extensor muscles, known as the ipsilateral and contralateral methods. Participant knees were fixed in 60° flexion, and each participant completed the entire set of measurements twice, 72 hours apart. [Results] The findings showed a good intraclass correlation coefficient of 0.73 to 0.81 for all muscle groups. The standard error of measurement and smallest detectable difference for flexor muscle groups were 0.37 and 1.02, respectively, while the values increased to standard error of measurement=0.38 and smallest detectable difference=1.05 for extensor muscle groups. [Conclusion] The device designed could quantify the forces producing/reproducing tasks on the knee joint with a high rate of reliability, and can probably be applied for outcome measurements in proprioceptive assessment of the knee joint. PMID:27630421

  5. Alterations in walking knee joint stiffness in individuals with knee osteoarthritis and self-reported knee instability.

    PubMed

    Gustafson, Jonathan A; Gorman, Shannon; Fitzgerald, G Kelley; Farrokhi, Shawn

    2016-01-01

    Increased walking knee joint stiffness has been reported in patients with knee osteoarthritis (OA) as a compensatory strategy to improve knee joint stability. However, presence of episodic self-reported knee instability in a large subgroup of patients with knee OA may be a sign of inadequate walking knee joint stiffness. The objective of this work was to evaluate the differences in walking knee joint stiffness in patients with knee OA with and without self-reported instability and examine the relationship between walking knee joint stiffness with quadriceps strength, knee joint laxity, and varus knee malalignment. Overground biomechanical data at a self-selected gait velocity was collected for 35 individuals with knee OA without self-reported instability (stable group) and 17 individuals with knee OA and episodic self-reported instability (unstable group). Knee joint stiffness was calculated during the weight-acceptance phase of gait as the change in the external knee joint moment divided by the change in the knee flexion angle. The unstable group walked with lower knee joint stiffness (p=0.01), mainly due to smaller heel-contact knee flexion angles (p<0.01) and greater knee flexion excursions (p<0.01) compared to their knee stable counterparts. No significant relationships were observed between walking knee joint stiffness and quadriceps strength, knee joint laxity or varus knee malalignment. Reduced walking knee joint stiffness appears to be associated with episodic knee instability and independent of quadriceps muscle weakness, knee joint laxity or varus malalignment. Further investigations of the temporal relationship between self-reported knee joint instability and walking knee joint stiffness are warranted.

  6. Runner's knee injuries.

    PubMed

    Lutter, L D

    1984-01-01

    In our series of running injuries 40% of all injuries have been related to the knee area. Over 20 million people in the United States run on a regular basis. Figures from large running sources show that 60% to 70% of individuals running regularly are injured severely enough to temporarily stop running. The figures are significant, not in the seriousness of the knee injury, but in the fact that seeking treatment for their knee problems. Orthopaedic surgeons, because of their ability to evaluate the entire lower extremity, become the central component for treatment of this large group of injured runners. As has been noted, the underlying biomechanical abnormality must be sought and dealt with or the symptoms return. By identification of the injured structure(s) integrated with biomechanical understanding, treatment can be developed on a rational basis, dealing with acute problems and prevention of future ones.

  7. In vivo six-degree-of-freedom knee-joint kinematics in overground and treadmill walking following total knee arthroplasty.

    PubMed

    Guan, Shanyuanye; Gray, Hans A; Schache, Anthony G; Feller, Julian; de Steiger, Richard; Pandy, Marcus G

    2016-10-22

    No data are available to describe six-degree-of-freedom (6-DOF) knee-joint kinematics for one complete cycle of overground walking following total knee arthroplasty (TKA). The aims of this study were firstly, to measure 6-DOF knee-joint kinematics and condylar motion for overground walking following TKA; and secondly, to determine whether such data differed between overground and treadmill gait when participants walked at the same speed during both tasks. A unique mobile biplane X-ray imaging system enabled accurate measurement of 6-DOF TKA knee kinematics during overground walking by simultaneously tracking and imaging the joint. The largest rotations occurred for flexion-extension and internal-external rotation whereas the largest translations were associated with joint distraction and anterior-posterior drawer. Strong associations were found between flexion-extension and adduction-abduction (R(2)  = 0.92), joint distraction (R(2)  = 1.00), and anterior-posterior translation (R(2)  = 0.77), providing evidence of kinematic coupling in the TKA knee. Although the measured kinematic profiles for overground walking were grossly similar to those for treadmill walking, several statistically significant differences were observed between the two conditions with respect to temporo-spatial parameters, 6-DOF knee-joint kinematics, and condylar contact locations and sliding. Thus, caution is advised when making recommendations regarding knee implant performance based on treadmill-measured knee-joint kinematic data. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

  8. Differential displacement of the human soleus and medial gastrocnemius aponeuroses during isometric plantar flexor contractions in vivo.

    PubMed

    Bojsen-Møller, Jens; Hansen, Philip; Aagaard, Per; Svantesson, Ulla; Kjaer, Michael; Magnusson, S Peter

    2004-11-01

    The human triceps surae muscle-tendon complex is a unique structure with three separate muscle compartments that merge via their aponeuroses into the Achilles tendon. The mechanical function and properties of these structures during muscular contraction are not well understood. The purpose of the study was to investigate the extent to which differential displacement occurs between the aponeuroses of the medial gastrocnemius (MG) and soleus (Sol) muscles during plantar flexion. Eight subjects (mean +/- SD; age 30 +/- 7 yr, body mass 76.8 +/- 5.5 kg, height 1.83 +/- 0.06 m) performed maximal isometric ramp contractions with the plantar flexor muscles. The experiment was performed in two positions: position 1, in which the knee joint was maximally extended, and position 2, in which the knee joint was maximally flexed (125 degrees ). Plantarflexion moment was assessed with a strain gauge load cell, and the corresponding displacement of the MG and Sol aponeuroses was measured by ultrasonography. Differential shear displacement of the aponeurosis was quantified by subtracting displacement of Sol from that of MG. Maximal plantar flexion moment was 36% greater in position 1 than in position 2 (132 +/- 20 vs. 97 +/- 11 N.m). In position 1, the displacement of the MG aponeurosis at maximal force exceeded that of the Sol (12.6 +/- 1.7 vs. 8.9 +/- 1.5 mm), whereas in position 2 displacement of the Sol was greater than displacement of the MG (9.6 +/- 1.0 vs. 7.9 +/- 1.2 mm). The amount and "direction" of shear between the aponeuroses differed significantly between the two positions across the entire range of contraction, indicating that the Achilles tendon may be exposed to intratendinous shear and stress gradients during human locomotion.

  9. Quadriceps and hamstrings fatigue alters hip and knee mechanics.

    PubMed

    Thomas, Abbey C; McLean, Scott G; Palmieri-Smith, Riann M

    2010-05-01

    Neuromuscular fatigue exacerbates abnormal landing strategies, which may increase noncontact anterior cruciate ligament (ACL) injury risk. The synergistic actions of quadriceps and hamstrings (QH) muscles are central to an upright landing posture, though the precise effect of simultaneous fatigue of these muscles on landing and ACL injury risk is unclear. Elucidating neuromechanical responses to QH fatigue thus appears important in developing more targeted fatigue-resistance intervention strategies. The current study thus aimed to examine the effects of QH fatigue on lower extremity neuromechanics during dynamic activity. Twenty-five healthy male and female volunteers performed three single-leg forward hops onto a force platform before and after QH fatigue. Fatigue was induced through sets of alternating QH concentric contractions, on an isokinetic dynamometer, until the first five repetitions of a set were performed at least 50% below QH peak torque. Three-dimensional hip and knee kinematics and normalized (body mass x height) kinetic variables were quantified for pre- and postfatigue landings and subsequently analyzed by way of repeated- measures mixed-model ANOVAs. QH fatigue produced significant increases in initial contact (IC) hip internal rotation and knee extension and external rotation angles (p < .05), with the increases in knee extension and external rotation being maintained at the time of peak vertical ground reaction force (vGRF) (p < .05). Larger knee extension and smaller knee flexion and external rotation moments were also evident at peak vGRF following fatigue (p < .05). Females landed with greater hip flexion and less abduction than males at both IC and peak vGRF as well as greater knee flexion at peak vGRF (p < .05). The peak vGRF was larger for females than males (p < .05). No sex x fatigue effects were found (p > .05). Fatigue of the QH muscles altered hip and knee neuromechanics, which may increase the risk of ACL injury. Prevention programs

  10. Dynamic Alignment Analysis in the Osteoarthritic Knee Using Computer Navigation.

    PubMed

    Larrainzar-Garijo, Ricardo; Murillo-Vizuete, David; Garcia-Bogalo, Raul; Escobar-Anton, David; Horna-Castiñeiras, Lissette; Peralta-Molero, Juan Vicente

    2017-02-13

    The lower limb alignment is influenced by the geometry of the joint surfaces and surrounding soft tissue tension. The mechanical behavior changes in a normal, osteoarthritic, and postoperative knee. The purpose of this study is to determine the dynamic coronal femoral tibial mechanical angle (FTMA) in osteoarthritic knees using computer navigation. The authors hypothesize that there are different varus-valgus patterns between flexion and extension in the osteoarthritic knee. We conducted a transversal observational study and included patients with osteoarthritis who underwent primary navigation TKA (Orthopilot version 4.2; B. Braun Aesculap, Tuttlingen, Germany). In total, 98 consecutive patients with 100 osteoarthritic knee joints, on which total knee arthroplasty was performed in our institution from 2009 to 2010, were enrolled in this prospective study. The FTMA was measured with the patient supine with maximum knee extension possible (considering the value as 0), 30, 60, and 90 degrees. All FMTA data obtained were segmented by hierarchic cluster measuring method. Through the clustering system, five segments were generated for varus patients and three for valgus patients: expected varus, expected valgus, severe varus, severe valgus, structured varus, structured valgus, concave varus, mixed varus-valgus, and mixed valgus-varus. The findings of the present study have demonstrated that there is a well-defined dynamic alignment in osteoarthritic knees, resulting in a wide kinematic variation in the coronal FTMA between flexion and full extension. Further studies will be necessary to determine whether this dynamic approach to FTMA has clinical utility in the surgeon's decision-making process.

  11. Axial disposition of myosin heads in isometrically contracting muscles.

    PubMed

    Juanhuix, J; Bordas, J; Campmany, J; Svensson, A; Bassford, M L; Narayanan, T

    2001-03-01

    Meridional x-ray diffraction diagrams, recorded with high angular resolution, from muscles contracting at the plateau of isometric tension show that the myosin diffraction orders are clusters of peaks. These clusters are due to pronounced interference effects between the myosin diffracting units on either side of the M-line. A theoretical analysis based on the polarity of the myosin (and actin) filaments shows that it is possible to extract phase information from which the axial disposition of the myosin heads can be determined. The results show that each head in a crown pair has a distinct structural disposition. It appears that only one of the heads in the pair stereospecifically interacts with the thin filament at any one time.

  12. Axial disposition of myosin heads in isometrically contracting muscles.

    PubMed Central

    Juanhuix, J; Bordas, J; Campmany, J; Svensson, A; Bassford, M L; Narayanan, T

    2001-01-01

    Meridional x-ray diffraction diagrams, recorded with high angular resolution, from muscles contracting at the plateau of isometric tension show that the myosin diffraction orders are clusters of peaks. These clusters are due to pronounced interference effects between the myosin diffracting units on either side of the M-line. A theoretical analysis based on the polarity of the myosin (and actin) filaments shows that it is possible to extract phase information from which the axial disposition of the myosin heads can be determined. The results show that each head in a crown pair has a distinct structural disposition. It appears that only one of the heads in the pair stereospecifically interacts with the thin filament at any one time. PMID:11222303

  13. Analysis of position and isometric joysticks for powered wheelchair driving.

    PubMed

    Cooper, R A; Jones, D K; Fitzgerald, S; Boninger, M L; Albright, S J

    2000-07-01

    The control interface is one of the most critical components of the electric-powered wheelchair (EPW). The control interface must accommodate the user's limitations and maximize the user's abilities. This study extended Fitts' Law for target-acquisition to a continuously updated target. The extended Fitts' Law was used to examine EPW driving with a standard position sensing joystick and a prototype isometric joystick (IJ). The extended Fitts' Law provides insight into the difficulty of performing target-acquisition tasks with an EPW. The test results showed significant differences (p < 0.05) among the two types of joysticks for selected measures of information processing capacity, movement time, root-mean-square-error, and average velocity while performing turning maneuvers. The mean values indicate that the IJ may provide superior turning performance.

  14. The susceptibility of the knee extensors to eccentric exercise-induced muscle damage is not affected by leg dominance but by exercise order.

    PubMed

    Hody, S; Rogister, B; Leprince, P; Laglaine, T; Croisier, J-L

    2013-09-01

    The aims of this study were first to compare the response of dominant and non-dominant legs to eccentric exercise and second, to examine whether there is an effect of exercise order on the magnitude of symptoms associated with intense eccentric protocols. Eighteen young men performed three sets of 30 maximal eccentric isokinetic (60° s(-1)) contractions of the knee extensors (range of motion, ROM: 0°-100°, 0 = full extension) using either dominant or non-dominant leg. They repeated a similar eccentric bout using the contralateral leg 6 weeks later. The sequence of leg's use was allocated to create equally balanced groups. Four indirect markers of muscle damage including subjective pain intensity, maximal isometric strength, muscle stiffness and plasma creatine kinase (CK) activity were measured before and 24 h after exercise. All markers changed significantly following the eccentric bout performed either by dominant or non-dominant legs, but no significant difference was observed between legs. Interestingly, the comparison between the first and second eccentric bouts revealed that muscle soreness (-42%, P<0.001), CK activity (-62%, P<0.05) and strength loss (-54%, P<0.01) were significantly lower after the second bout. This study suggests that leg dominance does not influence the magnitude of exercise-induced muscle damage and supports for the first time the existence of a contralateral protection against exercise-induced muscle damage in the lower limbs.

  15. Description of a standardized rehabilitation program based on sub-maximal eccentric following a platelet-rich plasma infiltration for jumper’s knee

    PubMed Central

    Kaux, Jean-François; Forthomme, Bénédicte; Namurois, Marie-Hélène; Bauvir, Philippe; Defawe, Nathalie; Delvaux, François; Lehance, Cédric; Crielaard, Jean-Michel; Croisier, Jean-Louis

    2014-01-01

    Summary Introduction. Different series emphasized the necessity of rehabilitation program after infiltration of platelet-rich plasma (PRP) in case of tendinopathy. However, most of them describe only briefly the reeducation protocol and these programs vary. Our aim was to extensively describe a specific standardized rehabilitation program. Methods. After a review of literature of post-PRP infiltration protocols, we had developed a standardized rehabilitation protocol. This protocol was evaluated by 30 subjects with chronic jumper’s knee who. A standardised progressive sub-maximal eccentric program supervised by a physical therapist for 6 weeks was started 1 week post-infiltration. The patient benefited also from electromyostimulation, isometric strengthening and stretching of the quadriceps, cycloergometer and cryotherapy. After the supervised program, the patient had to make an auto-reeducation added to the reathletisation protocol for 6 more weeks which was followed by maintenance exercises up to 1 year. The assessments were made using a VAS, IKDC and VISA-P scores. Results. The VAS, IKDC and VISA-P scores decreased very significantly with time. The compliance to auto-reeducation was good. Conclusions. We proposed a simple and efficient protocol based on sub-maximal eccentric reeducation to add to PRP infiltrations in case of patellar tendinopathy. PMID:24932453

  16. Cementless total knee arthroplasty

    PubMed Central

    Risitano, Salvatore; Sabatini, Luigi; Giachino, Matteo; Agati, Gabriele; Massè, Alessandro

    2016-01-01

    Interest for uncemented total knee arthroplasty (TKA) has greatly increased in recent years. This technique, less used than cemented knee replacement in the last decades, sees a revival thanks an advance in prosthetic design, instrumentation and operative technique. The related literature in some cases shows conflicting data on survival and on the revision’s rate, but in most cases a success rate comparable to cemented TKA is reported. The optimal fixation in TKA is a subject of debate with the majority of surgeons favouring cemented fixation. PMID:27162779

  17. Recovery Kinetics of Knee Flexor and Extensor Strength after a Football Match

    PubMed Central

    Draganidis, Dimitrios; Chatzinikolaou, Athanasios; Avloniti, Alexandra; Barbero-Álvarez, José C.; Mohr, Magni; Malliou, Paraskevi; Gourgoulis, Vassilios; Deli, Chariklia K.; Douroudos, Ioannis I.; Margonis, Konstantinos; Gioftsidou, Asimenia; Fouris, Andreas D.; Jamurtas, Athanasios Z.; Koutedakis, Yiannis; Fatouros, Ioannis G.

    2015-01-01

    We examined the temporal changes of isokinetic strength performance of knee flexor (KF) and extensor (KE) strength after a football match. Players were randomly assigned to a control (N = 14, participated only in measurements and practices) or an experimental group (N = 20, participated also in a football match). Participants trained daily during the two days after the match. Match and training overload was monitored with GPS devices. Venous blood was sampled and muscle damage was assessed pre-match, post-match and at 12h, 36h and 60h post-match. Isometric strength as well as eccentric and concentric peak torque of knee flexors and extensors in both limbs (dominant and non-dominant) were measured on an isokinetic dynamometer at baseline and at 12h, 36h and 60h after the match. Functional (KFecc/KEcon) and conventional (KFcon/KEcon) ratios were then calculated. Only eccentric peak torque of knee flexors declined at 60h after the match in the control group. In the experimental group: a) isometric strength of knee extensors and knee flexors declined (P<0.05) at 12h (both limbs) and 36h (dominant limb only), b) eccentric and concentric peak torque of knee extensors and flexors declined (P<0.05) in both limbs for 36h at 60°/s and for 60h at 180°/s with eccentric peak torque of knee flexors demonstrating a greater (P<0.05) reduction than concentric peak torque, c) strength deterioration was greater (P<0.05) at 180°/s and in dominant limb, d) the functional ratio was more sensitive to match-induced fatigue demonstrating a more prolonged decline. Discriminant and regression analysis revealed that strength deterioration and recovery may be related to the amount of eccentric actions performed during the match and athletes' football-specific conditioning. Our data suggest that recovery kinetics of knee flexor and extensor strength after a football match demonstrate strength, limb and velocity specificity and may depend on match physical overload and players' physical

  18. Variability of Measurement of Patellofemoral Indices with Knee Flexion and Quadriceps Contraction: An MRI-Based Anatomical Study

    PubMed Central

    Laugharne, Edward; Bali, Navi; Purushothamdas, Sanjay; Almallah, Faris; Kundra, Rik

    2016-01-01

    Purpose The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). Materials and Methods MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. Results With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31. Conclusions MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction. PMID:27894177

  19. EMGD-FE: an open source graphical user interface for estimating isometric muscle forces in the lower limb using an EMG-driven model

    PubMed Central

    2014-01-01

    Background This paper describes the “EMG Driven Force Estimator (EMGD-FE)”, a Matlab® graphical user interface (GUI) application that estimates skeletal muscle forces from electromyography (EMG) signals. Muscle forces are obtained by numerically integrating a system of ordinary differential equations (ODEs) that simulates Hill-type muscle dynamics and that utilises EMG signals as input. In the current version, the GUI can estimate the forces of lower limb muscles executing isometric contractions. Muscles from other parts of the body can be tested as well, although no default values for model parameters are provided. To achieve accurate evaluations, EMG collection is performed simultaneously with torque measurement from a dynamometer. The computer application guides the user, step-by-step, to pre-process the raw EMG signals, create inputs for the muscle model, numerically integrate the ODEs and analyse the results. Results An example of the application’s functions is presented using the quadriceps femoris muscle. Individual muscle force estimations for the four components as well the knee isometric torque are shown. Conclusions The proposed GUI can estimate individual muscle forces from EMG signals of skeletal muscles. The estimation accuracy depends on several factors, including signal collection and modelling hypothesis issues. PMID:24708668

  20. Arthroscopic-assisted Arthrodesis of the Knee Joint With the Ilizarov Technique: A Case Report and Literature Review.

    PubMed

    Waszczykowski, Michal; Niedzielski, Kryspin; Radek, Maciej; Fabis, Jaroslaw

    2016-01-01

    Arthrodesis of the knee joint is a mainly a salvage surgical procedure performed in cases of infected total knee arthroplasty, tumor, failed knee arthroplasty or posttraumatic complication.The authors report the case of 18-year-old male with posttraumatic complication of left knee because of motorbike accident 1 year before. He was treated immediately after the injury in the local Department of Orthopaedics and Traumatology. The examination in the day of admission to our department revealed deformation of the left knee, massive scar tissue adhesions to the proximal tibial bone and multidirectional instability of the knee. The plain radiographs showed complete lack of lateral compartment of the knee joint and patella. The patient complained of severe instability and pain of the knee and a consecutive loss of supporting function of his left limb. The authors decided to perform an arthroscopic-assisted fusion of the knee with Ilizarov external fixator because of massive scar tissue in the knee region and the prior knee infection.In the final follow-up after 54 months a complete bone fusion, good functional and clinical outcome were obtained.This case provides a significant contribution to the development and application of low-invasive techniques in large and extensive surgical procedures in orthopedics and traumatology. Moreover, in this case fixation of knee joint was crucial for providing good conditions for the regeneration of damaged peroneal nerve.

  1. The influence of knee position on ankle dorsiflexion - a biometric study

    PubMed Central

    2014-01-01

    Background Musculus gastrocnemius tightness (MGT) can be diagnosed by comparing ankle dorsiflexion (ADF) with the knee extended and flexed. Although various measurement techniques exist, the degree of knee flexion needed to eliminate the effect of the gastrocnemius on ADF is still unknown. The aim of this study was to identify the minimal degree of knee flexion required to eliminate the restricting effect of the musculus gastrocnemius on ADF. Methods Bilateral ADF of 20 asymptomatic volunteers aged 18-40 years (50% female) was assessed prospectively at six different degrees of knee flexion (0°, 20°, 30°, 45°, 60°, 75°, Lunge). Tests were performed following a standardized protocol, non weightbearing and weightbearing, by two observers. Statistics comprised of descriptive statistics, t-tests, repeated measurement ANOVA and ICC. Results 20 individuals with a mean age of 27 ± 4 years were tested. No significant side to side differences were observed. The average ADF [95% confidence interval] for non weightbearing was 4° [1°-8°] with the knee extended and 20° [16°-24°] for the knee 75° flexed. Mean weightbearing ADF was 25° [22°-28°] for the knee extended and 39° [36°-42°] for the knee 75° flexed. The mean differences between 20° knee flexion and full extension were 15° [12°-18°] non weightbearing and 13° [11°-16°] weightbearing. Significant differences of ADF were only found between full extension and 20° of knee flexion. Further knee flexion did not increase ADF. Conclusion Knee flexion of 20° fully eliminates the ADF restraining effect of the gastrocnemius. This knowledge is essential to design a standardized clinical examination assessing MGT. PMID:25053374

  2. [Management of Flexion Contracture in Primary Total Knee Arthroplasty].

    PubMed

    Hube, R; Mayr, H O; Pfitzner, T; von Roth, P

    2015-06-01

    Flexion contracture is a common deformity of the arthritic knee. The present publication describes causes, clinical relevance and surgical technique in the presence of flexion contractures in total knee arthroplasty. Flexion contracture can be attributed to different causes. Basically it is a mismatch between flexion and extension gaps. Moderate and severe deformities have to be corrected by additional surgical interventions. In most cases soft tissue techniques with release of contracted structures, the removal of osteophytes and additional distal femoral bone resection are necessary. The goal of these interventions is to achieve full extension of the knee. During rehabilitation attention has to be paid to maintain it with intensive physical therapy. A remaining flexion contracture is associated with inferior functional outcome and persistent pain.

  3. How effective is multiple needle puncturing for medial soft tissue balancing during total knee arthroplasty? A cadaveric study.

    PubMed

    Koh, In Jun; Kwak, Dai-Soon; Kim, Tae Kyun; Park, In Joo; In, Yong

    2014-12-01

    We investigated the quantitative effect and risk factors for over-release during multiple needle puncturing (MNP) for medial gap balancing in varus total knee arthroplasty (TKA). Of the ten pairs of cadaveric knees, one knee from each pair was randomly assigned to undergo MNP in extension (E group), while the other knee underwent MNP in flexion (F group). The increased extension and 90° flexion gaps after every five needle punctures were measured until over-release occurred. The extension gap (< 4mm) and the 90° flexion gap (< 6mm) gradually increased in both groups. The 90° flexion gaps increased more selectively than did the extension gaps. MNP in the flexed knee, a narrow MCL, and severe osteoarthritis were associated with a smaller number of MNPs required to over-release.

  4. Acute patellar dislocation with multiple ligament injuries after knee dislocation and single session reconstruction.

    PubMed

    Gormeli, Gokay; Gormeli, Cemile Ayse; Karakaplan, Mustafa; Gurbuz, Sukru; Ozdemir, Zeynep; Ozer, Mustafa

    2016-06-01

    Knee dislocation is a relatively rare condition of all orthopaedic injuries. Accompanying multiple ligament injuries are common after knee dislocations. A 41-year-old male presented to the emergency department suffering from right knee dislocation in June 2013. The patient had anterior cruciate ligament, medial collateral ligament (MCL), medial patellofemoral ligament (MPFL) rupture, and lateral meniscal tear. A single-bundle anatomic reconstruction, medial collateral ligament reconstruction, medial patellofemoral ligament reconstruction and meniscus repair were performed in single session. At twelve months follow-up; there was 160º flexion and 10° extension knee range of motion. Lysholm knee score was 90. Extensive forces can cause both MCL and MPFL injury due to overload and the anatomical relationship between these two structures. Therefore, patients with valgus instability should be evaluated for both MPFL and MCL tears to facilitate successful treatment.

  5. Current distribution in skeletal muscle activated by functional electrical stimulation: image-series formulation and isometric recruitment curve.

    PubMed

    Livshitz, L M; Einziger, P D; Mizrahi, J

    2000-01-01

    The present work develops an analytical model that allows one to estimate the current distribution within the whole muscle and the resulting isometric recruitment curve (IRC). The quasistatic current distribution, expressed as an image series, i.e., a collection of properly weighted and shifted point-source responses, outlines an extension for more than three layers of the classical image theory in conductive plane-stratified media. Evaluation of the current distribution via the image series expansions requires substantially less computational time than the standard integral representation. The expansions use a unique recursive representation for Green's function, that is a generic characteristic of the stratification. This approach permits one to verify which of the tissue electrical properties are responsible for the current density distribution within the muscle, and how significant their combinations are. In addition, the model permits one to study the effect of different electrode placement on the shape and the magnitude of the potential distribution. A simple IRC model was used for parameter estimation and model verification by comparison with experimentally obtained isometric recruitment curves. Sensitivity of the model to different parameters such as conductivity of the tissues and activation threshold was verified. The resulting model demonstrated characteristic features that were similar to those of experimentally obtained data. The model also quantitatively confirmed the differences existing between surface (transcutaneous) and implanted (percutaneous) electrode stimulation.

  6. The effects of knee injury on skeletal muscle function, Na+, K+-ATPase content, and isoform abundance

    PubMed Central

    Perry, Ben D; Levinger, Pazit; Morris, Hayden G; Petersen, Aaron C; Garnham, Andrew P; Levinger, Itamar; McKenna, Michael J

    2015-01-01

    While training upregulates skeletal muscle Na+, K+-ATPase (NKA), the effects of knee injury and associated disuse on muscle NKA remain unknown. This was therefore investigated in six healthy young adults with a torn anterior cruciate ligament, (KI; four females, two males; age 25.0 ± 4.9 years; injury duration 15 ± 17 weeks; mean ± SD) and seven age- and BMI-matched asymptomatic controls (CON; five females, two males). Each participant underwent a vastus lateralis muscle biopsy, on both legs in KI and one leg in CON. Muscle was analyzed for muscle fiber type and cross-sectional area (CSA), NKA content ([3H]ouabain binding), and α1–3 and β1–2 isoform abundance. Participants also completed physical activity and knee function questionnaires (KI only); and underwent quadriceps peak isometric strength, thigh CSA and postural sway assessments in both injured and noninjured legs. NKA content was 20.1% lower in the knee-injured leg than the noninjured leg and 22.5% lower than CON. NKA α2 abundance was 63.0% lower in the knee-injured leg than the noninjured leg, with no differences in other NKA isoforms. Isometric strength and thigh CSA were 21.7% and 7.1% lower in the injured leg than the noninjured leg, respectively. In KI, postural sway did not differ between legs, but for two-legged standing was 43% higher than CON. Hence, muscle NKA content and α2 abundance were reduced in severe knee injury, which may contribute to impaired muscle function. Restoration of muscle NKA may be important in rehabilitation of muscle function after knee and other lower limb injury. PMID:25677549

  7. Intrarater reliability of hand held dynamometry in measuring lower extremity isometric strength using a portable stabilization device.

    PubMed

    Jackson, Steven M; Cheng, M Samuel; Smith, A Russell; Kolber, Morey J

    2017-02-01

    Hand held dynamometry (HHD) is a more objective way to quantify muscle force production (MP) compared to traditional manual muscle testing. HHD reliability can be negatively impacted by both the strength of the tester and the subject particularly in the lower extremities due to larger muscle groups. The primary aim of this investigation was to assess intrarater reliability of HHD with use of a portable stabilization device for lower extremity MP in an athletic population. Isometric lower extremity strength was measured for bilateral lower extremities including hip abductors, external rotators, adductors, knee extensors, and ankle plantar flexors was measured in a sample of healthy recreational runners (8 male, 7 females, = 30 limbs) training for a marathon. These measurements were assessed using an intrasession intrarater reliability design. Intraclass correlation coefficients (ICC) were calculated using 3,1 model based on the single rater design. The standard error of measurement (SEM) for each muscle group was also calculated. ICC were excellent ranging from ICC (3,1) = 0.93-0.98 with standard error of measurements ranging from 0.58 to 17.2 N. This study establishes the use of a HHD with a portable stabilization device as demonstrating good reliability within testers for measuring lower extremity muscle performance in an active healthy population.

  8. Mechanical loading of knee articular cartilage induced by muscle contraction can be assessed by measuring electrical potentials at the surface of the knee.

    PubMed

    Zhu, Lin; Buschmann, Michael D; Savard, Pierre

    2016-02-08

    Electroarthrography (EAG) consists of recording electrical potentials on the knee surface that originate from streaming potentials within articular cartilage while the joint is undergoing compressive loading. The aim was to investigate how the contraction of specific leg muscles affects the contact force of the knee joint and, in turn, the EAG values. For six normal subjects, voluntary isometric muscle contractions were repeatedly conducted to activate four leg muscle groups while the subject was lying on his back. Two EAG signals were recorded on the medial and lateral sides of the knee, as well as four EMG signals (gastrocnemius, hamstring, quadriceps, tensor fascia latae), and the signal from a force plate fixed against the foot according to the direction of the force. The EAG and force signals were very well correlated: the median of the correlation coefficients between an EAG signal and the corresponding force signal during each loading cycle was 0.91, and 86% of the correlation coefficients were statistically significant (p<5%). Isolated muscle contraction was possible for the gastrocnemius and hamstring, but not always for the quadriceps and tensor fascia latae. Using the clinical loading protocol which consists of a one-legged stance, the quadriceps and hamstring EMGs showed minimal activity; loading cycles with increased EAG amplitude were associated with higher EMG activity from the gastrocnemius, which is involved in antero-posterior balance. These results document the role of the EAG as a "sensor" of the knee contact force and contribute to the development of clinical loading protocols with improved reproducibility.

  9. Reading Knee-Deep

    ERIC Educational Resources Information Center

    Jewett, Pamela

    2007-01-01

    Freire told his audience at a seminar at the University of Massachusetts, "You need to read knee-deep in texts, for deeper than surface meanings, and you need to know the words to be able to do it" (quoted in Cleary, 2003). In a children's literature class, fifteen teachers and I traveled along a path that moved us toward reading…

  10. Hypermobility and Knee Injuries.

    ERIC Educational Resources Information Center

    Steiner, Mark E.

    1987-01-01

    A review of research on the effect of hypermobility on knee injury indicates that greater than normal joint flexibility may be necessary for some athletic endeavors and that it may be possible to change one's underlying flexibility through training. However, for most athletes, inherited flexibility probably plays only a small role, if any, in…

  11. Impaired varus-valgus proprioception and neuromuscular stabilization in medial knee osteoarthritis.

    PubMed

    Chang, Alison H; Lee, Song Joo; Zhao, Heng; Ren, Yupeng; Zhang, Li-Qun

    2014-01-22

    Impaired proprioception and poor muscular stabilization in the frontal plane may lead to knee instability during functional activities, a common complaint in persons with knee osteoarthritis (KOA). Understanding these frontal plane neuromechanical properties in KOA will help elucidate the factors contributing to knee instability and aid in the development of targeted intervention strategies. The objectives of the study were to compare knee varus-valgus proprioception, isometric muscle strength, and active muscular contribution to stability between persons with medial KOA and healthy controls. We evaluated knee frontal plane neuromechanical parameters in 14 participants with medial KOA and 14 age- and gender-matched controls, using a joint driving device (JDD) with a customized motor and a 6-axis force sensor. Analysis of covariance with BMI as a covariate was used to test the differences in varus-valgus neuromechanical parameters between these two groups. The KOA group had impaired varus proprioception acuity (1.08±0.59° vs. 0.69±0.49°, p<0.05), decreased normalized varus muscle strength (1.31±0.75% vs. 1.79±0.84% body weight, p<0.05), a trend toward decreased valgus strength (1.29±0.67% vs. 1.88±0.99%, p=0.054), and impaired ability to actively stabilize the knee in the frontal plane during external perturbation (4.67±2.86 vs. 8.26±5.95 Nm/degree, p<0.05). The knee frontal plane sensorimotor control system is compromised in persons with medial KOA. Our findings suggest varus-valgus control deficits in both the afferent input (proprioceptive acuity) and muscular effectors (muscle strength and capacity to stabilize the joint).

  12. Influence of Total Knee Arthroplasty on Gait Mechanics of the Replaced and Non-Replaced Limb During Stair Negotiation.

    PubMed

    Standifird, Tyler W; Saxton, Arnold M; Coe, Dawn P; Cates, Harold E; Reinbolt, Jeffrey A; Zhang, Songning

    2016-01-01

    This study compared biomechanics during stair ascent in replaced and non-replaced limbs of total knee arthroplasty (TKA) patients with control limbs of healthy participants. Thirteen TKA patients and fifteen controls performed stair ascent. Replaced and non-replaced knees of TKA patients were less flexed at contact compared to controls. The loading response peak knee extension moment was greater in control and non-replaced knees compared with replaced. The push-off peak knee abduction moment was elevated in replaced limbs compared to controls. Loading and push-off peak hip abduction moments were greater in replaced limbs compared to controls. The push-off peak hip abduction moment was greater in non-replaced limbs compared to controls. Future rehabilitation protocols should consider the replaced knee and also the non-replaced knee and surrounding joints.

  13. The Transseptal Arthroscopic Knee Portal Is in Close Proximity to the Popliteal Artery: A Cadaveric Study.

    PubMed

    Cancienne, Jourdan M; Werner, Brian C; Burrus, M Tyrrell; Kandil, Abdurrahman; Conte, Evan J; Gwathmey, Frank W; Miller, Mark D

    2017-03-10

    The purpose of this study was to use fluoroscopy to measure the distance between the transseptal portal and the popliteal artery under arthroscopic conditions with an intact posterior knee capsule, and to determine the difference between 90 degrees of knee flexion and full extension. The popliteal artery of eight fresh-frozen cadaveric knees was dissected and cannulated proximal to the knee joint. The posterolateral, posteromedial, and transseptal portals were then established at 90 degrees of flexion. A 4-mm switching stick was placed through the transseptal portal, and barium contrast was injected into the popliteal artery. A lateral fluoroscopic image was taken with the knee in 90 degrees of flexion and full extension, and the distance between the popliteal artery and the switching stick was measured and compared using a paired t-test. In knee flexion, the average distance between the transseptal portal and the anterior aspect of the popliteal artery for the eight cadaveric specimens was 12.0 mm ± 3.3 mm; in extension, this decreased to 9.0 mm ± 2.7 mm. The distance between the transseptal portal and popliteal artery was significantly higher at 90 degrees of knee flexion as compared with extension (p = 0.0005). The transseptal posterior knee arthroscopic portal must be carefully created due to the close proximity to the popliteal artery, and may be closer to the artery than previously reported in specimens with an intact posterior knee capsule. Creating the portal with the knee in flexion significantly displaces the popliteal artery away from the portal reducing the risk of arterial injury.

  14. Total Arthroplasty in Ankylosed Knees: A Case Series

    PubMed Central

    Camanho, Gilberto Luiz

    2009-01-01

    OBJECTIVE To present nine patients with ankylosis in their knees that were submitted to a total arthroplasty to lessen their pain and improve their functional limitation. For these patients, arthrodesis remained a possibility in the event of arthroplasty failure. INTRODUCTION Ankylosis of the knee is a severe functional limitation that becomes worse when pain is present. Arthrodesis of the knee is a classical indication for such patients, since it resolves the pain; however, the severe functional limitation remains. METHODS In the present study, we evaluated the clinical course of nine patients who underwent total arthroplasty of the knee, and were followed up for at least five years. RESULTS The results demonstrate that all of the patients experienced a significant reduction in pain and some improvement in the degree of knee flexion and extension. CONCLUSION Based on the latest follow-up, there has been no need to perform arthrodesis for any of our patients, showing that a total arthroplasty could be a option for treatment in knee ankylosis. PMID:19330242

  15. Squat exercise to estimate knee megaprosthesis rehabilitation: a pilot study

    PubMed Central

    Lovecchio, Nicola; Zago, Matteo; Sciumè, Luciana; Lopresti, Maurizio; Sforza, Chiarella

    2015-01-01

    [Purpose] This study evaluated a specific rehabilitation protocol using a half squat after total knee reconstruction with distal femur megaprosthesis and tibial allograft-prosthesis composite. [Subject and Methods] Squat execution was recorded by a three-dimensional system before and after a specific rehabilitation program on a 28-year-old patient. Squat duration, body center of mass trajectory, and vertical range of motion were determined. Step width and joint angles and symmetry (hip flexion, extension, and rotation, knee flexion, and ankle dorsal and plantar flexion) were estimated. Knee and hip joint symmetry was computed using a bilateral cyclogram technique. [Results] After rehabilitation, the squat duration was longer (75%), step width was similar, and vertical displacement was higher. Hip flexion increased by over 20%, and ankle dorsiflexion diminished by 14%. The knee had the highest symmetry gain (4.1–3.4%). Angle-angle plot subtended areas decreased from 108° to 40°2 (hip) and from 204° to 85°2 (knee), showing improvement in movement symmetry. [Conclusion] We concluded that the squat is an effective multifactorial exercise to estimate rehabilitation outcomes after megaprosthesis, also considering that compressive and shear forces are minimal up to 60–70° of knee flexion. PMID:26311992

  16. Squat exercise to estimate knee megaprosthesis rehabilitation: a pilot study.

    PubMed

    Lovecchio, Nicola; Zago, Matteo; Sciumè, Luciana; Lopresti, Maurizio; Sforza, Chiarella

    2015-07-01

    [Purpose] This study evaluated a specific rehabilitation protocol using a half squat after total knee reconstruction with distal femur megaprosthesis and tibial allograft-prosthesis composite. [Subject and Methods] Squat execution was recorded by a three-dimensional system before and after a specific rehabilitation program on a 28-year-old patient. Squat duration, body center of mass trajectory, and vertical range of motion were determined. Step width and joint angles and symmetry (hip flexion, extension, and rotation, knee flexion, and ankle dorsal and plantar flexion) were estimated. Knee and hip joint symmetry was computed using a bilateral cyclogram technique. [Results] After rehabilitation, the squat duration was longer (75%), step width was similar, and vertical displacement was higher. Hip flexion increased by over 20%, and ankle dorsiflexion diminished by 14%. The knee had the highest symmetry gain (4.1-3.4%). Angle-angle plot subtended areas decreased from 108° to 40°(2) (hip) and from 204° to 85°(2) (knee), showing improvement in movement symmetry. [Conclusion] We concluded that the squat is an effective multifactorial exercise to estimate rehabilitation outcomes after megaprosthesis, also considering that compressive and shear forces are minimal up to 60-70° of knee flexion.

  17. Differential activity of regions of the psoas major and quadratus lumborum during submaximal isometric trunk efforts.

    PubMed

    Park, Rachel J; Tsao, Henry; Cresswell, Andrew G; Hodges, Paul W

    2012-02-01

    Controversy exists regarding the function of psoas major (PM) and quadratus lumborum (QL) at the lumbar spine. The functions of discrete regions of PM and QL were studied during trunk loading tasks. Twelve healthy participants performed isometric trunk loading tasks in various directions in upright sitting. Fine-wire electromyography (EMG) electrodes were inserted under ultrasound guidance into PM fascicles arising from the transverse process (PM-t) and vertebral body (PM-v) and the anterior (QL-a) and posterior (QL-p) layers of QL on the right side. Although right PM-t and PM-v were both active during right lateral-flexion trunk efforts, their activity was opposite in the sagittal plane, with greater PM-t towards extension and PM-v towards flexion. QL-a and QL-p were similarly active, though QL-p was active to a greater percentage of MVC during right trunk lateral-flexion efforts. Activity of QL-p was modulated with respiratory phase during the loading tasks with trunk efforts towards the right lateral-flexion/flexion and right lateral-flexion directions. These findings provide novel understanding of the unique activation of discrete regions of PM and QL. These differences must be considered in future EMG studies to better understand the function of these deeply situated trunk muscles in the control of the lumbar spine.

  18. A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions.

    PubMed

    Contreras, Bret; Vigotsky, Andrew D; Schoenfeld, Brad J; Beardsley, Chris; Cronin, John

    2015-01-01

    Background. The purpose of this study was to compare the peak electromyography (EMG) of the most commonly-used position in the literature, the prone bent-leg (90°) hip extension against manual resistance applied to the distal thigh (PRONE), to a novel position, the standing glute squeeze (SQUEEZE). Methods. Surface EMG electrodes were placed on the upper and lower gluteus maximus of thirteen recreationally active females (age = 28.9 years; height = 164 cm; body mass = 58.2 kg), before three maximum voluntary isometric contraction (MVIC) trials for each position were obtained in a randomized, counterbalanced fashion. Results. No statistically significant (p < 0.05) differences were observed between PRONE (upper: 91.94%; lower: 94.52%) and SQUEEZE (upper: 92.04%; lower: 85.12%) for both the upper and lower gluteus maximus. Neither the PRONE nor SQUEEZE was more effective between all subjects. Conclusions. In agreement with other studies, no single testing position is ideal for every participant. Therefore, it is recommended that investigators employ multiple MVIC positions, when possible, to ensure accuracy. Future research should investigate a variety of gluteus maximus MVIC positions in heterogeneous samples.

  19. A comparison of two gluteus maximus EMG maximum voluntary isometric contraction positions

    PubMed Central

    Contreras, Bret; Schoenfeld, Brad J.; Beardsley, Chris; Cronin, John

    2015-01-01

    Background. The purpose of this study was to compare the peak electromyography (EMG) of the most commonly-used position in the literature, the prone bent-leg (90°) hip extension against manual resistance applied to the distal thigh (PRONE), to a novel position, the standing glute squeeze (SQUEEZE). Methods. Surface EMG electrodes were placed on the upper and lower gluteus maximus of thirteen recreationally active females (age = 28.9 years; height = 164 cm; body mass = 58.2 kg), before three maximum voluntary isometric contraction (MVIC) trials for each position were obtained in a randomized, counterbalanced fashion. Results. No statistically significant (p < 0.05) differences were observed between PRONE (upper: 91.94%; lower: 94.52%) and SQUEEZE (upper: 92.04%; lower: 85.12%) for both the upper and lower gluteus maximus. Neither the PRONE nor SQUEEZE was more effective between all subjects. Conclusions. In agreement with other studies, no single testing position is ideal for every participant. Therefore, it is recommended that investigators employ multiple MVIC positions, when possible, to ensure accuracy. Future research should investigate a variety of gluteus maximus MVIC positions in heterogeneous samples. PMID:26417543

  20. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  1. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  2. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  3. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  4. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  5. 21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made...

  6. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  7. 21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be...

  8. [Effect of thyroidectomy on energetics of isometric muscle contraction in white rats].

    PubMed

    Soboliev, V I; Moskalets', T V

    2007-01-01

    The effect of thyroidactomia on parameters of energetics of isometric contractions of front shin--bone muscle of white rats is studied in in situ experiments. It is shown that experimental atiriosis lengthen considerably the latent period of muscle contractions (+95%) considerably reduce (in 5.5 times) the speed of it contraction in first phase of contraction act and also considerably increase the time (+37%), which necessery for developing maximum strength of contraction. Thyroidactomia with general negative influence on ergothropic characteristics of isometric muscle contraction decrease considerably the expenditure of thermal energy on maximum strength of contraction unit (-17%) or on middle isometric tension unit (-9.3%).

  9. Validation of a novel smartphone accelerometer-based knee goniometer.

    PubMed

    Ockendon, Matthew; Gilbert, Robin E

    2012-09-01

    Loss of full knee extension following anterior cruciate ligament surgery has been shown to impair knee function. However, there can be significant difficulties in accurately and reproducibly measuring a fixed flexion of the knee. We studied the interobserver and the intraobserver reliabilities of a novel, smartphone accelerometer-based, knee goniometer and compared it with a long-armed conventional goniometer for the assessment of fixed flexion knee deformity. Five healthy male volunteers (age range 30 to 40 years) were studied. Measurements of knee flexion angle were made with a telescopic-armed goniometer (Lafayette Instrument, Lafayette, IN) and compared with measurements using the smartphone (iPhone 3GS, Apple Inc., Cupertino, CA) knee goniometer using a novel trigonometric technique based on tibial inclination. Bland-Altman analysis of validity and reliability including statistical analysis of correlation by Pearson's method was undertaken. The iPhone goniometer had an interobserver correlation (r) of 0.994 compared with 0.952 for the Lafayette. The intraobserver correlation was r = 0.982 for the iPhone (compared with 0.927). The datasets from the two instruments correlate closely (r = 0.947) are proportional and have mean difference of only -0.4 degrees (SD 3.86 degrees). The Lafayette goniometer had an intraobserver reliability +/- 9.6 degrees. The interobserver reliability was +/- 8.4 degrees. By comparison the iPhone had an interobserver reliability +/- 2.7 degrees and an intraobserver reliability +/- 4.6 degrees. We found the iPhone goniometer to be a reliable tool for the measurement of subtle knee flexion in the clinic setting.

  10. Medial knee joint loading increases in those who respond to hyaluronan injection for medial knee osteoarthritis.

    PubMed

    Briem, Kristin; Axe, Michael J; Snyder-Mackler, Lynn

    2009-11-01

    Knee osteoarthritis (OA) is a cause of decline in function and the medial compartment is often affected. Intraarticular injection of hyaluronic acid (HA) is indicated as a symptom modifying treatment with at least 6 months passing between consecutive injection series. The effects of HA injection on gait variables have not been extensively examined. Therefore, our objective was to investigate the effects of HA injection on gait in people with medial knee OA. Twenty-seven subjects were included; each was tested prior to treatment (baseline), no later than 3 weeks following the last injection (post-HA), and again 5 months after treatment ended (follow-up). Responder criteria were defined to identify responders and non-responders. Subjects underwent 3D gait analysis, muscle activity was sampled, and co-contraction indices were calculated. Responders experienced increased peak knee adduction moments post-HA, whereas non-responders did not. Improved self-report scores were associated with increased knee adduction moments and increased medial co-contraction. Pain relief may result in higher loading onto the already vulnerable medial compartment due to changes in lower limb mechanics and muscle activation patterns. Eventually this may result in a more rapid progression of joint deterioration.

  11. Importance of the different posterolateral knee static stabilizers: biomechanical study

    PubMed Central

    Lasmar, Rodrigo Campos Pace; Marques de Almeida, Adriano; Serbino, José Wilson; da Mota Albuquerque, Roberto Freire; Hernandez, Arnaldo José

    2010-01-01

    PURPOSE The purpose of this study was to evaluate the relative importance of the different static stabilizers of the posterolateral corner of the knee in cadavers. METHODS Tests were performed with the application of a varus and external rotation force to the knee in extension at 30 and 60 degrees of flexion using 10 cadaver knees. The forces were applied initially to an intact knee and then repeated after a selective sectioning of the ligaments into the following: section of the lateral collateral ligament; section of the lateral collateral ligament and the popliteofibular complex; and section of the lateral collateral ligament, the popliteofibular complex and the posterolateral capsule. The parameters studied were the angular deformity and stiffness when the knees were submitted to a 15 Newton-meter varus torque and a 6 Newton-meter external tibial torque. Statistical analysis was performed using the ANOVA (Analysis of Variance) and Tukey’s tests. RESULTS AND CONCLUSION Our findings showed that the lateral collateral ligament was important in varus stability at 0, 30 and 60 degrees. The popliteofibular complex was the most important structure for external rotation stability at all angles of flexion and was also important for varus stability at 30 and 60 degrees. The posterolateral capsule was important for varus stability at 0 and 30 degrees and for external rotation stability in extension. Level of evidence: Level IV (cadaver study). PMID:20454502

  12. Redox state changes in human skeletal muscle after isometric contraction.

    PubMed Central

    Henriksson, J; Katz, A; Sahlin, K

    1986-01-01

    Subjects maintained an isometric contraction of the quadriceps femoris muscle at two-thirds maximal voluntary contraction (m.v.c.) force for 5 s (5.0 +/- 0.3 s; mean +/- S.E. of mean; n = 6) or until fatigue (52 +/- 4 s; n = 13). Muscle biopsies were obtained at rest, immediately after the contractions and also at 1 and 4 min of recovery after contraction to fatigue. In all subjects 5 s isometric contraction resulted in an increase of muscle NADH (0.084 +/- 0.012 at rest to 0.203 +/- 0.041 mmol/kg dry wt.) and a decrease of phosphocreatine (PC; change in concentration = -17.3 +/- 3.8 mmol/kg dry wt.). Glucose-6-phosphate concentration was more than doubled whereas lactate increased in only four of the six subjects. The two subjects who did not show any increase in lactate also had the lowest increase in NADH. At fatigue NADH increased to 0.226 +/- 0.032 mmol/kg dry wt. which was not significantly different from the value after 5 s contraction. Muscle PC was nearly depleted and lactate increased 12-fold above resting levels. The major part (65%) of the NADH increase at fatigue had reverted after 1 min recovery but only a slight further decrease occurred between 1 and 4 min of recovery. In relative terms the time course of the changes in muscle NADH during the first minute of recovery was similar to that of PC resynthesis, suggesting a common regulator such as O2 availability. In contrast to the delayed return of NADH concentration, PC resynthesis continued during the later part of the recovery period and PC concentration was almost fully restored after 4 min of recovery. It is concluded that muscle NADH is already maximally increased in the first seconds of muscle contraction at two-thirds m.v.c. Indirect evidence indicates that this increase reflects a reduction of the mitochondrial NAD-NADH redox couple. The rapid establishment of a reduced mitochondrial redox state at the start of muscle contraction will probably lead to a reduction of the redox state in the

  13. Longitudinal changes in knee joint biomechanics during level walking following anterior cruciate ligament reconstruction surgery.

    PubMed

    Webster, Kate E; Feller, Julian A; Wittwer, Joanne E

    2012-06-01

    Following anterior cruciate ligament reconstruction (ACL) patients have altered movement patterns in the reconstructed knee during walking. There is limited information about these alterations over an extended period of time. This study was designed to present a longitudinal analysis of gait patterns following ACL reconstruction surgery. Assessments of level walking were undertaken in 16 participants at a mean 10 months (initial assessment) and again at 3 years (follow-up assessment) after ACL reconstruction surgery. Kinematic and kinetic variables were analysed using a two factor (time, limb) repeated measures ANOVA. Kinematic data showed that patients were able to achieve greater extension about the reconstructed knee at follow-up than at initial assessment. The reconstructed knee was significantly less internally rotated than the contralateral knee at the initial assessment but not at follow-up. Kinetic data showed a significant increase in the external knee extension moment for the reconstructed limb over time. There were also significant increases in the external knee adduction moment for both limbs at the follow-up assessment. The external knee adduction moment was however smaller in the reconstructed knee than the contralateral knee at both assessments. The results indicate that gait variables do change over time and that measurement at a single time point may not reflect the long term outcome of ACL reconstruction surgery. The changes were however small and may not be clinically relevant. However, the consistently reduced external knee adduction moment seen about the reconstructed knee in this study may suggest that factors other than joint moments influence degenerative change over time.

  14. Management of the Swollen Knee

    PubMed Central

    Stanish, William D.; Rice, William; Ratson, Gary; Loebenberg, Mark; Langley, Linda

    1988-01-01

    The primary-care physician plays a critical role in the diagnosis, initial treatment, and subsequent rehabilitation of many orthopedic conditions. The knee is the most frequently injured joint in sport medicine. The family physician must therefore be familiar with the etiology, cause, and natural history of problems related to the knee joint. The swollen knee is one of the most common ailments the family physician is asked to assess in his or her busy day-to-day practice of medicine. He or she must therefore remain abreast of the dynamic field of diagnostic procedures, treatments, and rehabilitative measures relating to many knee injuries. This paper deals with the more common causes of the acutely swollen knee, paying particular attention to the infected knee and the acute hemarthrosis. It should provide answers to most questions about diagnosis, initial treatment, and subsequent management of this problem. PMID:21264033

  15. Clipped random wave analysis of isometric lamellar microemulsions

    PubMed

    Choy; Chen

    2000-04-01

    We have made small angle neutron scattering studies of C10E4-D2O-octane isometric microemulsions in the lamellar phase at the hydrophile-lipophile balance temperature. The scattering intensity distributions were then analyzed with a particular choice of a spectral density function (SDF) derived by maximization of generalized entropy. The model agrees well with the measured intensities on an absolute scale, and allowed us to derive various length scales associated with the microemulsion mesoscopic structure as well as the average interfacial curvatures. We also used the experimentally determined SDF to generate a three-dimensional snapshot of the fluctuating microemulsion microstructure. Unlike conventional pictures of extended lamellar planes, we observed small domains which were internally lamellar but randomly oriented with respect to each other. Finally, we computed the probability distributions of the mean curvature H and the Gaussian curvature K on the oil-water interface. The former showed a symmetric distribution centered around H = 0, while the latter showed a skewed distribution peaked at a negative value of K, but with a wing extending to positive values.

  16. Recruitment stability in masseter motor units during isometric voluntary contractions.

    PubMed

    Scutter, S D; Türker, K S

    1998-10-01

    Recruitment of single motor units (SMUs) of the masseter muscle was studied using macro representation (MacroRep) as the indicator of motor unit size. When subjects followed a slow isometric force ramp, units were usually recruited in order of MacroRep size. However, pooling the data from repeated ramps in the same subject resulted in a weak relationship between MacroRep size and force recruitment threshold, probably due to marked variations in the relative contributions of the jaw muscles, and varying levels of cocontraction, in the development of total bite force in each ramp. The force recruitment thresholds of individual SMUs showed marked variability, but recruitment threshold stability was improved when expressed as a percentage of maximum surface electromyographic (SEMG) activity in the ipsilateral masseter. Therefore the SEMG recruitment threshold was concluded to be a more stable and accurate indicator of the SMU's position in the recruitment hierarchy in a given muscle. It was concluded that SMUs in masseter are recruited according to the size principle, and that when investigating recruitment in jaw muscles, SEMG recruitment threshold should be used in preference to force recruitment threshold.

  17. Clipped random wave analysis of isometric lamellar microemulsions

    SciTech Connect

    Choy, Dawen; Chen, Sow-Hsin

    2000-04-01

    We have made small angle neutron scattering studies of C{sub 10}E{sub 4}-D{sub 2}O-octane isometric microemulsions in the lamellar phase at the hydrophile-lipophile balance temperature. The scattering intensity distributions were then analyzed with a particular choice of a spectral density function (SDF) derived by maximization of generalized entropy. The model agrees well with the measured intensities on an absolute scale, and allowed us to derive various length scales associated with the microemulsion mesoscopic structure as well as the average interfacial curvatures. We also used the experimentally determined SDF to generate a three-dimensional snapshot of the fluctuating microemulsion microstructure. Unlike conventional pictures of extended lamellar planes, we observed small domains which were internally lamellar but randomly oriented with respect to each other. Finally, we computed the probability distributions of the mean curvature H and the Gaussian curvature K on the oil-water interface. The former showed a symmetric distribution centered around H = 0, while the latter showed a skewed distribution peaked at a negative value of K, but with a wing extending to positive values. (c) 2000 The American Physical Society.

  18. Acoustic myography compared to electromyography during isometric fatigue and recovery.

    PubMed

    Rodriquez, A A; Agre, J C; Knudtson, E R; Franke, T M; Ng, A V

    1993-02-01

    This study compared the acoustic (RMS-AMG) to electromyographic (RMS-EMG) signal, median frequency of EMG power spectrum (Fm), and quadriceps torque during isometric fatiguing contraction (FC) and recovery. Seven subjects were tested for strength (MVC) and then, on separate days, maintained 20%, 40%, or 80% MVC to exhaustion followed by MVC testing at regular intervals. Throughout FC, RMS-EMG significantly (P < 0.05) increased and Fm significantly (P < 0.05) decreased during all trials; RMS-AMG significantly (P < 0.05) increased only during the 20% and 40% trials. During recovery, MVC and RMS-EMG recovered most slowly after the 20% trial and most rapidly after the 80% trial; Fm and RMS-AMG recovered by 90 seconds after all trials. RMS-AMG reflects RMS-EMG during low but not high levels of FC. Recovery of strength is most depressed following FC at lower relative levels of torque. We conclude that RMS-AMG behaves differently than RMS-EMG, torque, and Fm during FC and recovery.

  19. Preliminary study of optimal measurement location on vibroarthrography for classification of patients with knee osteoarthritis

    PubMed Central

    Ota, Susumu; Ando, Akiko; Tozawa, Yusuke; Nakamura, Takuya; Okamoto, Shogo; Sakai, Takenobu; Hase, Kazunori

    2016-01-01

    [Purpose] The aims of the present study were to investigate the most suitable location for vibroarthrography measurements of the knee joint to distinguish a healthy knee from knee osteoarthritis using Wavelet transform analysis. [Subjects and Methods] Participants were 16 healthy females and 17 females with severe knee osteoarthritis. Vibroarthrography signals were measured on the medial and lateral epicondyles, mid-patella, and tibia using stethoscopes with a microphone while subjects stood up from a seated position. Frequency and knee flexion angles at the peak wavelet coefficient were obtained. [Results] Peak wavelet coefficients at the lateral condyle and tibia were significantly higher in patients with knee osteoarthritis than in the control group. Knee joint angles at the peak wavelet coefficient were smaller (more extension) in the osteoarthritis group compared to the control group. The area under the receiver operating characteristic curve on tibia assessment with the frequency and knee flexion angles was higher than at the other measurement locations (both area under the curve: 0.86). [Conclusion] The tibia is the most suitable location for classifying knee osteoarthritis based on vibroarthrography signals. PMID:27821959

  20. Wear-simulation analysis of rotating-platform mobile-bearing knees.

    PubMed

    Fisher, John; McEwen, Hannah; Tipper, Joanne; Jennings, Louise; Farrar, Richard; Stone, Martin; Ingham, Eileen

    2006-09-01

    The wear and wear debris from rotating-platform mobile-bearing knees and fixed-bearing knees were compared in knee joint-simulator studies. The wear rate of the fixed-bearing knees was found to increase as the kinematics were increased because of an increase in internal-external rotation and an increase in anterorposterior (AP) translation. The wear rate of the rotating-platform mobile-bearing knees was found to be significantly lower than that of the fixed-bearing knees. The rotating-platform mobile-bearing knee was able to decouple the complex kinematics to pure rotation at the inferior tibial articulating surface and linear flexion-extension and AP sliding at the superior femoral articulating interface, substantially reducing cross-shear and wear. No difference was found in the wear debris between the rotating-platform and fixed-bearing knees. This resulted in a substantially reduced functional biological activity or osteolytic potential for the rotating-platform mobile-bearing knees due to the lower wear rates.

  1. Kinematic Analysis of Gait Following Intra-articular Corticosteroid Injection into the Knee Joint with an Acute Exacerbation of Arthritis

    PubMed Central

    Mehta, Saurabh; Szturm, Tony; El-Gabalawy, Hani S.

    2011-01-01

    ABSTRACT Purpose: The objective of this study was to examine the effects of intra-articular corticosteroid injection (ICI) on ipsilateral knee flexion/extension, ankle dorsiflexion/plantarflexion (DF/PF), and hip abduction/adduction (abd/add) during stance phase in people with an acute exacerbation of rheumatoid arthritis (RA) of the knee joint. The study also assessed the effects of ICI on spatiotemporal parameters of gait and functional status in this group. Methods: Nine people with an exacerbation of RA of the knee were recruited. Kinematic and spatiotemporal gait parameters were obtained for each participant. Knee-related functional status was assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS). Spatiotemporal gait parameters and joint angles (knee flexion, ankle DF/PF, hip abd/add) of the affected side were compared pre- and post-ICI. Results: Data for eight people were available for analysis. Median values for knee flexion and ankle PF increased significantly following ICI. Gait parameters of cadence, velocity, bilateral stride length, bilateral step length, step width, double-support percentage, and step time on the affected side also showed improvement. Pain and knee-related functional status as measured by the KOOS showed improvement. Conclusions: This study demonstrated a beneficial short-term effect of ICI on knee-joint movements, gait parameters, and knee-related functional status in people with acute exacerbation of RA of the knee. PMID:22942516

  2. Elastic properties of an intact and ACL-ruptured knee joint: measurement, mathematical modelling, and haptic rendering.

    PubMed

    Frey, Martin; Riener, Robert; Michas, Christian; Regenfelder, Felix; Burgkart, Rainer

    2006-01-01

    An analytical, dynamic model of the human knee joint has been developed to simulate the unloaded knee joint behaviour in 6 degrees of freedom. It is based on extensive robot-based measurements of the elastic properties of a human cadaver knee joint. The measured data are compared with data from the literature to ensure that a proper database for modelling is used. The analytical modelling of the passive elastic joint properties is done with Local Linear Model Trees. The deduced knee joint model incorporates passive elastic properties of the internal knee joint structures, passive elastic muscle forces, damping forces, gravitational forces, and external forces. There are two sets of parameters, one simulating the movement of the intact knee joint, and a second simulating the knee joint with ruptured anterior cruciate ligament. The dynamic model can be easily processed in real-time. It is implemented in the haptic display of the Munich Knee Joint Simulator (MKS), which enables a person to move a plastic leg driven by a robot manipulator and feel the simulated knee joint force. Orthopaedic physicians judged the performance of the dynamic knee joint model by executing physical knee joint tests at the MKS.

  3. The effect of local skin cooling before a sustained, submaximal isometric contraction on fatigue and isometric quadriceps femoris performance: A randomized controlled trial.

    PubMed

    Hohenauer, Erich; Cescon, Corrado; Deliens, Tom; Clarys, Peter; Clijsen, Ron

    2017-04-01

    The central- and peripheral mechanisms by which heat strain limits physical performance are not fully elucidated. Nevertheless, pre-cooling is often used in an attempt to improve subsequent performance. This study compared the effects of pre-cooling vs. a pre-thermoneutral application on central- and peripheral fatigue during 60% of isometric maximum voluntary contraction (MVC) of the right quadriceps femoris muscle. Furthermore, the effects between a pre-cooling and a pre-thermoneutral application on isometric MVC of the right quadriceps femoris muscle and subjective ratings of perceived exertion (RPE) were investigated. In this randomized controlled trial, 18 healthy adults voluntarily participated. The participants received either a cold (experimental) application (+8°C) or a thermoneutral (control) application (+32°C) for 20min on their right thigh (one cuff). After the application, central (fractal dimension - FD) and peripheral (muscle fiber conduction velocity - CV) fatigue was estimated using sEMG parameters during 60% of isometric MVC. Surface EMG signals were detected from the vastus medialis and lateralis using bidimensional arrays. Immediately after the submaximal contraction, isometric MVC and RPE were assessed. Participants receiving the cold application were able to maintain a 60% isometric MVC significantly longer when compared to the thermoneutral group (mean time: 78 vs. 46s; p=0.04). The thermoneutral application had no significant impact on central fatigue (p>0.05) compared to the cold application (p=0.03). However, signs of peripheral fatigue were significantly higher in the cold group compared to the thermoneutral group (p=0.008). Pre-cooling had no effect on isometric MVC of the right quadriceps muscle and ratings of perceived exertion. Pre-cooling attenuated central fatigue and led to significantly longer submaximal contraction times compared to the pre-thermoneutral application. These findings support the use of pre-cooling procedures

  4. Perioperative pain management for total knee arthroplasty.

    PubMed

    Baratta, Jaime L; Gandhi, Kishor; Viscusi, Eugene R

    2014-01-01

    Pain management following total knee arthroplasty (TKA) can be challenging. Inadequate pain management following TKA may inhibit rehabilitation, increase morbidity and mortality, decrease patient satisfaction, and lead to chronic persistent postsurgical pain. Traditionally the mainstay of postoperative pain management was opioids; however, the current recommendations to pain management emphasize a multimodal approach and minimizing opioids whenever possible. With careful planning and a multimodal analgesic approach instituted perioperatively, appropriate pain management following TKA can be achieved. Utilizing an extensive review of the literature, this article discusses the analgesic techniques available for the perioperative management of TKA.

  5. The relationship between isometric and dynamic strength in college football players.

    PubMed

    McGuigan, Michael R; Winchester, Jason B

    2008-01-01

    Previous research has demonstrated the importance of both dynamic and isometric maximal strength and rate of force development (RFD) in athletic populations. The purpose of this study was to examine the relationships between measures of isometric force (PF), RFD, jump performance and strength in collegiate football athletes. The subjects in this study were twenty-two men [(mean ± SD):age 18.4 ± 0.7 years; height 1.88 ± 0.07 m; mass 107.6 ± 22.9 kg] who were Division I college football players. They were tested for PF using the isometric mid thigh pull exercise. Explosive strength was measured as RFD from the isometric force-time curve. The one repetition maximum (1RM) for the squat, bench press and power clean exercises were determined as measures of dynamic strength. The two repetition maximum (2RM) for the split jerk was also determined. Vertical jump height and broad jump was measured to provide an indication of explosive muscular power. There were strong to very strong correlations between measures of PF and 1RM (r = 0. 61 - 0.72, p < 0.05). The correlations were very strong between the power clean 1RM and squat 1RM (r = 0.90, p < 0.05). There were very strong correlations between 2RM split jerk and clean 1RM (r = 0.71, p < 0.05), squat 1RM (r = 0.71, p < 0.05), bench 1RM (r = 0.70, p < 0.05) and PF (r = 0.72, p < 0.05). There were no significant correlations with RFD. The isometric mid thigh pull test does correlate well with 1RM testing in college football players. RFD does not appear to correlate as well with other measures. The isometric mid thigh pull provides an efficient method for assessing isometric strength in athletes. This measure also provides a strong indication of dynamic performance in this population. Key pointsIn Division I college football players the isometric mid thigh pull test correlates well with 1RM testing.Rate of Force Development does not appear to be as closely related to dynamic and isometric strength in college football

  6. Selectively lockable knee brace

    NASA Technical Reports Server (NTRS)

    Myers, Neill (Inventor); Shadoan, Mike (Inventor); Forbes, John (Inventor); Baker, Kevin (Inventor)

    1994-01-01

    A knee brace for aiding in rehabilitation of damaged leg muscles includes upper and lower housings, normally pivotable, one relative to the other about the knee joint axis of a patient. The upper housing is attachable to the thigh of the patient above the knee joint, while the lower housing is secured to a stirrup which extends downwardly along the patient's leg and is attached to the patient's shoe. An actuation rod is carried within the lower housing and is coupled to a cable. The upper and lower housings carry cooperative clutch/brake elements which normally are disengaged to permit relative movement between the upper and lower housings. When the cable is extended, the clutch/brake elements engage and lock the housings together. A heel strike mechanism fastened to the stirrup and the heel of the shoe is connected to the cable to selectively extend the cable and lock the brace in substantially any position when the patient places weight on the heel.

  7. Selectively Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    Myers, W. Neill (Inventor); Shadoan, Michael D. (Inventor); Forbes, John C. (Inventor); Baker, Kevin J. (Inventor); Rice, Darron C. (Inventor)

    1996-01-01

    A knee brace for aiding in rehabilitation of damaged leg muscles includes upper and lower housings normally pivotable one relative to the other about the knee joint axis of a patient. The upper housing is attachable to the thigh of the patient above the knee joint while the lower housing is secured to a stirrup which extends downwardly along the patient's leg and is attached to the patient's shoe. An actuation rod is carried within the lower housing and is coupled to a cable. The upper and lower housings carry cooperative clutch/brake elements which normally are disengaged to permit relative movement between the upper and lower housings. When the cable is extended the clutch/brake elements engage and lock the housings together. A heel strike mechanism fastened to the stirrup and the heel of the shoe is connected to the cable to selectively extend the cable and lock the brace in substantially any position when the patient places weight on the heel.

  8. Comparative Analysis of Positive and Negative Lateral Acceleration on Isometric Fatigue.

    DTIC Science & Technology

    1982-12-01

    of Neck Muscle Fatigue Due to Lateral Acceleration by Surface EMG Analysis. MS Thesis . Wright State University, Ohio: School of Aerospace Medicine...LATERAL ACCELERATION ON MS Thesis ISOMETRIC FATIGUE IN THE FOREARM 6. PERFORMING ORG. REPORT NUMBER F 7. AUTHOR(*) 13. CONTRACT OR GRANT NUMBER(o...acceleration environment. The DES and surface electromyogram ( EMG ) techniques were used to measure any differ- ences In Isometric strength, endurance, and

  9. Validation and Reliability of a Novel Test of Upper Body Isometric Strength

    PubMed Central

    Bellar, David; Marcus, Lena; Judge, Lawrence W.

    2015-01-01

    The purpose of the present investigation was to examine the association of a novel test of upper body isometric strength against a 1RM bench press measurement. Forty college age adults (n = 20 female, n = 20 male; age 22.8 ± 2.8 years; body height 171.6 ± 10.8 cm; body mass 73.5 ± 16.3 kg; body fat 23.1 ± 5.4%) volunteered for the present investigation. The participants reported to the lab on three occasions. The first visit included anthropometric measurements and familiarization with both the upper body isometric test and bench press exercise. The final visits were conducted in a randomized order, with one being a 1RM assessment on the bench press and the other consisting of three trials of the upper body isometric assessment. For the isometric test, participants were positioned in a “push-up” style position while tethered (stainless steel chain) to a load cell (high frequency) anchored to the ground. The peak isometric force was consistent across all three trials (ICC = 0.98) suggesting good reliability. Multiple regression analysis was completed with the predictors: peak isometric force, gender, against the outcome variable 1RM bench press. The analysis resulted in a significant model (r2 = 0.861, p≤0.001) with all predictor variables attaining significance in the model (p<0.05). Isometric peak strength had the greatest effect on the model (Beta = 5.19, p≤0.001). Results from this study suggest that the described isometric upper body strength assessment is likely a valid and reliable tool to determine strength. Further research is warranted to gather a larger pool of data in regard to this assessment. PMID:26557203

  10. Knee stabilization in patients with medial compartment knee osteoarthritis

    PubMed Central

    Lewek, Michael D.; Ramsey, Dan K.; Snyder-Mackler, Lynn; Rudolph, Katherine S.

    2005-01-01

    OBJECTIVE Individuals with medial knee osteoarthritis (MKOA) experience knee laxity and instability. Muscle stabilization strategies may influence the long term integrity of the joint. In this study we determined how individuals with medial knee OA respond to a rapid valgus knee movement to investigate the relationship between muscle stabilization strategies and knee instability. METHODS Twenty one subjects with MKOA and genu varum, and 19 control subjects were tested. Subjects stood with the test limb on a moveable platform that translated laterally to rapidly stress the knee’s medial periarticular structures and create a potentially destabilizing feeling at the knee joint. Knee motion and muscle responses were recorded. Subjects rated their knee instability with a self-report questionnaire about knee instability during daily activities. RESULTS Prior to plate movement the OA subjects demonstrated more medial muscle co-contraction (p=0.014). Following plate movement the OA subjects shifted less weight off the test limb (p = 0.013) and had more medial co-contraction (p=0.037). Those without instability had higher VMMH co-contraction than those who reported more instability (p=0.038). Knee stability correlated positively with VMMH co-contraction prior to plate movement (r = 0.459; p = 0.042). CONCLUSION This study demonstrates that individuals with MKOA attempt to stabilize the knee with greater medial muscle co-contraction in response to laxity that appears on only the medial side of the joint. This strategy presumably contributes to higher joint compression and could exacerbate joint destruction and needs to be altered to slow or stop the progression of the OA disease process. PMID:16142714

  11. Effects of 17-day spaceflight on knee extensor muscle function and size

    NASA Technical Reports Server (NTRS)

    Tesch, Per A.; Berg, Hans E.; Bring, Daniel; Evans, Harlan J.; LeBlanc, Adrian D.

    2005-01-01

    It is generally held that space travelers experience muscle dysfunction and atrophy during exposure to microgravity. However, observations are scarce and reports somewhat inconsistent with regard to the time course, specificity and magnitude of such changes. Hence, we examined four male astronauts (group mean approximately 43 years, 86 kg and 183 cm) before and after a 17-day spaceflight (Space Transport System-78). Knee extensor muscle function was measured during maximal bilateral voluntary isometric and iso-inertial concentric, and eccentric actions. Cross-sectional area (CSA) of the knee extensor and flexor, and gluteal muscle groups was assessed by means of magnetic resonance imaging. The decrease in strength (P<0.05) across different muscle actions after spaceflight amounted to 10%. Eight ambulatory men, examined on two occasions 20 days apart, showed unchanged (P>0.05) muscle strength. CSA of the knee extensor and gluteal muscles, each decreased (P<0.05) by 8%. Knee flexor muscle CSA showed no significant (P>0.05) change. The magnitude of these changes concord with earlier results from ground-based studies of similar duration. The results of this study, however, do contrast with the findings of no decrease in maximal voluntary ankle plantar flexor force previously reported in the same crew.

  12. Development of a knee joint motion simulator to evaluate deep knee flexion of artificial knee joints.

    PubMed

    Takano, Y; Ueno, M; Kiguchi, K; Ito, J; Mawatari, M; Hotokebuchi, T

    2008-01-01

    A purpose of this study is to examine the effect that quadriceps femoris force gives to rotation angle and joint reaction force of total knee prosthesis during deep knee flexion such as a unique sitting style called 'seiza' in Japanese. For the evaluation, we developed the knee motion simulator which could bend to 180 degrees continually simulating the passive flexion performed by clinicians. A total knee prosthesis, which is a specially-devised posterior stabilized type and capable of flexion up to 180 degrees, was inserted into bone model. And this prosthesis pulled by three kinds of quadriceps femoris forces to perform parameter study. The results obtained in this study were showed the same tendency with those in the past cadaveric experiment. It is suggested that the rotation angle and joint reaction force of total knee prosthesis are affected by shape of prosthesis, a vector of quadriceps femoris force, and bony aliments during deep knee flexion.

  13. Explosive force production during isometric squats correlates with athletic performance in rugby union players.

    PubMed

    Tillin, Neale Anthony; Pain, Matthew Thomas Gerard; Folland, Jonathan

    2013-01-01

    This study investigated the association between explosive force production during isometric squats and athletic performance (sprint time and countermovement jump height). Sprint time (5 and 20 m) and jump height were recorded in 18 male elite-standard varsity rugby union players. Participants also completed a series of maximal- and explosive-isometric squats to measure maximal force and explosive force at 50-ms intervals up to 250 ms from force onset. Sprint performance was related to early phase (≤100 ms) explosive force normalised to maximal force (5 m, r = -0.63, P = 0.005; and 20 m, r = -0.54, P = 0.020), but jump height was related to later phase (>100 ms) absolute explosive force (0.51 < r < 0.61; 0.006 < P < 0.035). When participants were separated for 5-m sprint time (< or ≥ 1s), the faster group had greater normalised explosive force in the first 150 ms of explosive-isometric squats (33-67%; 0.001 < P < 0.017). The results suggest that explosive force production during isometric squats was associated with athletic performance. Specifically, sprint performance was most strongly related to the proportion of maximal force achieved in the initial phase of explosive-isometric squats, whilst jump height was most strongly related to absolute force in the later phase of the explosive-isometric squats.

  14. Distinct molecular processes associated with isometric force generation and rapid tension recovery after quick release.

    PubMed Central

    Brenner, B; Chalovich, J M; Yu, L C

    1995-01-01

    It was proposed by Huxley and Simmons (Nature 1971, 233:533-538) that force-generating cross-bridges are attached to actin in several stable positions. In this concept, isometric force is generated by the same mechanism as the quick tension recovery after an abrupt release of length; i.e., when crossbridges proceed from the first postulated stable position to the second and/or subsequent positions, resulting in straining of the elastic elements within the cross-bridges. Therefore, isometric force is generated by cross-bridges in the second or even subsequent stable positions. However, through mechanical measurements of skinned rabbit psoas muscle fibers, we found that during isometric contraction only the first stable state is significantly occupied; i.e., isometric force is generated by cross-bridges in the first of the stable states. Thus, isometric force and the quick tension recovery appear to result from two distinctly different molecular processes. We propose that isometric force results from a structural change in the actomyosin complex associated with the transition from a weakly bound configuration to a strongly bound configuration before the reaction steps in the Huxley-Simmons model, whereas a major component of quick tension recovery originates from transitions among the subsequent strongly bound states. Mechanical, biochemical, and structural evidence for the two distinct processes is summarized and reviewed. PMID:7787051

  15. Distinct molecular processes associated with isometric force generation and rapid tension recovery after quick release.

    PubMed

    Brenner, B; Chalovich, J M; Yu, L C

    1995-04-01

    It was proposed by Huxley and Simmons (Nature 1971, 233:533-538) that force-generating cross-bridges are attached to actin in several stable positions. In this concept, isometric force is generated by the same mechanism as the quick tension recovery after an abrupt release of length; i.e., when crossbridges proceed from the first postulated stable position to the second and/or subsequent positions, resulting in straining of the elastic elements within the cross-bridges. Therefore, isometric force is generated by cross-bridges in the second or even subsequent stable positions. However, through mechanical measurements of skinned rabbit psoas muscle fibers, we found that during isometric contraction only the first stable state is significantly occupied; i.e., isometric force is generated by cross-bridges in the first of the stable states. Thus, isometric force and the quick tension recovery appear to result from two distinctly different molecular processes. We propose that isometric force results from a structural change in the actomyosin complex associated with the transition from a weakly bound configuration to a strongly bound configuration before the reaction steps in the Huxley-Simmons model, whereas a major component of quick tension recovery originates from transitions among the subsequent strongly bound states. Mechanical, biochemical, and structural evidence for the two distinct processes is summarized and reviewed.

  16. Isometric joystick: a study of control by adolescents and young adults with cerebral palsy.

    PubMed

    Stewart, H; Noble, G; Seeger, B R

    1992-03-01

    This research was undertaken to determine the best wheelchair driving method for clients with cerebral palsy who were experiencing difficulties using displacement joysticks. The hypothesis was that adolescents with cerebral palsy would perform better in a tracking task using an isometric joystick (which has no moving parts) than a displacement joystick of the type used in commercial wheelchair controllers. A series of single subject case studies was performed in which the activating force of the isometric joystick was individualised for each subject. Comparative evaluation of the isometric joystick and a displacement joystick was then carried out. Results indicate that performance using the displacement joystick was superior to performance with the isometric joystick for the able-bodied subject and four of the five subjects with cerebral palsy. One of the subjects showed significantly better performance on the displacement joystick using his hand, and no significant difference between joysticks using his foot. The remaining subject, who used his foot, showed no significant difference between joysticks. These findings suggest that subjects with cerebral palsy with prior experience using a displacement joystick do not appear to benefit by the use of an isometric joystick compared to a displacement joystick. No difference in the use of the two joysticks was found for subjects with cerebral palsy who had no prior experience using a joystick. This suggests that an isometric joystick is an option for people beginning to learn to drive an electric wheelchair.

  17. Medial pivot knee in primary total knee arthroplasty.

    PubMed

    Atzori, Francesco; Salama, Wael; Sabatini, Luigi; Mousa, Shazly; Khalefa, Abdelrahman

    2016-01-01

    Total knee arthroplasty (TKA) with a medial pivot design was developed in order to mimic normal knee kinematics; the highly congruent medial compartment implant should improve clinical results and decrease contact stresses. Clinical and radiographic mid-term outcomes are satisfactory, but we need other studies to evaluate long-term results and indications for unusual cases.

  18. Intraoperative Manipulation for Flexion Contracture During Total Knee Arthroplasty.

    PubMed

    Matsui, Yoshio; Minoda, Yukihide; Fumiaki, Inori; Nakagawa, Sigeru; Okajima, Yoshiaki; Kobayashi, Akio

    2016-11-01

    Joint gap balancing during total knee arthroplasty (TKA) is important for ensuring postoperative joint stability and range of motion. Although the joint gap should be balanced to ensure joint stability, it is not easy to achieve perfect balancing during TKA. In particular, relative extension gap shortening can induce flexion contracture. Intraoperative manipulation is often empirically performed. This study evaluated the tension required for this manipulation and investigated the influence of intraoperative manipulation on the joint gap in cadaveric knees. Total knee arthroplasty was performed in 6 cadaveric knees from whole body cadavers. Flexion contracture was induced using an insert that was 4 mm thicker than the extension gap, and intraoperative manipulation was performed. Study measurements included the changes in the joint gap after manipulation at 6 positions, with the knee bending from extension to 120° flexion, and the manipulation tension that was required to create a 4-mm increase in the gap. The manipulation tension needed to create a 4-mm increase in the extension gap was 303±17 N. The changes in the joint gap after manipulation were 0.4 mm, 0.6 mm, 0.2 mm, -0.2 mm, -0.4 mm, and -0.6 mm at 0°, 30°, 45°, 60°, 90°, and 120° flexion, respectively. Therefore, the joint gap was not significantly changed by the manipulation. Intraoperative manipulation does not resolve flexion contracture. Therefore, if flexion contracture occurs during TKA, treatment with additional bone cutting and soft tissue release is likely more appropriate than manipulation. [Orthopedics. 2016; 39(6):e1070-e1074.].

  19. [Soft tissue balancing in total condylar knee arthroplasty].

    PubMed

    Trepte, C T; Pfanzelt, K

    2003-01-01

    Soft tissue balancing and correct bone cuts are an entity in correcting malalignment in total knee arthroplasty, and cannot be considered isolated. Distinct bony deformations/deviations need enlarged soft tissue management. The extent of resection of the bone stock has to be planned exactly before the operation. Exact soft tissue balancing is necessary to stabilize the corrected knee. Soft tissue balancing has to be done primarily on the side of the contracture by lengthening of the shortened and contracted structures. After balancing the ligaments should have the same tension in extension and flexion together with the same height of the extension and flexion gap. Because of the classic resection of the tibial head, the femoral resection must follow the Insall-Line, that means 3 degrees to 5 degrees outer rotation in relation to the condyles. Only in this way a symmetric flexion gap can be achieved in combination with ligamentous stability in extension and flexion.

  20. Intercondylar notch fibrous nodule after total knee replacement.

    PubMed

    Carro, L P; Suarez, G G

    1999-01-01

    Intra-articular fibrous bands and soft-tissue impingement under the patella after total knee replacement are a well known complications that can be diagnosed and treated arthroscopically. Arthroscopic treatment of soft-tissue impingement between femoral and tibial components in a total knee arthroplasty has been recently reported. The purpose of this article is to report one more case of this pathology of a more fibrotic type resembling a nodule in the intercondylar notch that prevents total extension and to discuss the possible origin and clinical significance. Finally, we propose a classification of the fibrotic reactions after total knee arthroplasty: (A)Multiples or complex bundles reactions; and (B)singles or isolates nodular forms: fibrous nodule in the femoropatelar area (clunk syndrome), and fibrous nodule in the intercondylar notch.

  1. Design and Characterization of a Novel Knee Articulation Mechanism

    NASA Astrophysics Data System (ADS)

    Olinski, M.; Gronowicz, A.; Handke, A.; Ceccarelli, M.

    2016-08-01

    The paper is focused on designing a novel controllable and adjustable mechanism for reproducing human knee joint's complex motion by taking into account the flexion/extension movement in the sagittal plane, in combination with roll and slide. Main requirements for a knee rehabilitation supporting device are specified by researching the knee's anatomy and already existing mechanisms. A three degree of freedom (3 DOF) system (four-bar like linkage with controlled variable lengths of rockers) is synthesised to perform the reference path of instantaneous centre of rotation (ICR). Finally, a preliminary design of the adaptive mechanism is elaborated and a numerical model is built in Adams. Numerical results are derived from simulations that are presented to evaluate the accuracy of the reproduced movement and the mechanism's capabilities.

  2. Energy cost of isometric force production after active shortening in skinned muscle fibres.

    PubMed

    Joumaa, V; Fitzowich, A; Herzog, W

    2017-02-23

    The steady state isometric force after active shortening of a skeletal muscle is lower than the purely isometric force at the corresponding length. This property of skeletal muscle is known as force depression. The purpose of this study was to investigate whether the energy cost of force production at the steady state after active shortening was reduced compared to the energy cost of force production for a purely isometric contraction performed at the corresponding length (same length, same activation). Experiments were performed in skinned fibres isolated from rabbit psoas muscle. Skinned fibres were actively shortened from an average sarcomere length of 3.0 µm to an average sarcomere length of 2.4 µm. Purely isometric reference contractions were performed at an average sarcomere length of 2.4 µm. Simultaneously with the force measurements, the ATP cost was measured during the last 30 seconds of isometric contractions using an enzyme-coupled assay. Stiffness was calculated during a quick stretch-release cycle of 0.2% fibre length performed once the steady state had been reached after active shortening and during the purely isometric reference contractions. Force and stiffness following active shortening were decreased by 10.0±1.8% and 11.0±2.2%, respectively compared to the isometric reference contractions. Similarly, ATPase activity per second (not normalized to the force) showed a decrease of 15.6±3.0% in the force depressed state compared to the purely isometric reference state. However, ATPase activity per second per unit of force was similar for the isometric contractions following active shortening (28.7±2.4 mM/mN.s.mm(3)) and the corresponding purely isometric reference contraction (30.9±2.8 mM/mN.s.mm(3)). Furthermore, the reduction in absolute ATPase activity per second was significantly correlated with force depression and stiffness depression. These results are in accordance with the idea that force depression following active shortening is

  3. New Generation Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    1996-01-01

    A knee brace that uses Space Shuttle propulsion technology has moved a step closer to being available to help knee injury and stroke patients and may possibly benefit patients with birth defects, spinal cord injuries, and post-polio conditions. After years of hard work, inventors at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have turned over the final design and prototype to industry partners at Horton's Orthotic Lab in Little Rock, Arkansas for further clinical testing. The device, called the Selectively Lockable Knee Brace, may mean faster, less painful rehabilitation for patients by allowing the knee to move when weight is not on the heel. Devices currently on the market lock the knee in a rigid, straight-leg position, or allow continuous free motion. Pictured here is a knee brace prototype being tested and fitted at Horton's Orthotic Lab. The knee brace is just one example of how space technology is being used to improve the lives of people on Earth. NASA's MSFC inventors Michael Shadoan and Neill Myers are space propulsion engineers who use the same mechanisms and materials to build systems for rockets that they used to design and develop the knee brace.

  4. Automatic locking orthotic knee device

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce C. (Inventor)

    1993-01-01

    An articulated tang in clevis joint for incorporation in newly manufactured conventional strap-on orthotic knee devices or for replacing such joints in conventional strap-on orthotic knee devices is discussed. The instant tang in clevis joint allows the user the freedom to extend and bend the knee normally when no load (weight) is applied to the knee and to automatically lock the knee when the user transfers weight to the knee, thus preventing a damaged knee from bending uncontrollably when weight is applied to the knee. The tang in clevis joint of the present invention includes first and second clevis plates, a tang assembly and a spacer plate secured between the clevis plates. Each clevis plate includes a bevelled serrated upper section. A bevelled shoe is secured to the tank in close proximity to the bevelled serrated upper section of the clevis plates. A coiled spring mounted within an oblong bore of the tang normally urges the shoes secured to the tang out of engagement with the serrated upper section of each clevic plate to allow rotation of the tang relative to the clevis plate. When weight is applied to the joint, the load compresses the coiled spring, the serrations on each clevis plate dig into the bevelled shoes secured to the tang to prevent relative movement between the tang and clevis plates. A shoulder is provided on the tang and the spacer plate to prevent overextension of the joint.

  5. Exercise and the Knee Joint.

    ERIC Educational Resources Information Center

    Clarke, H. Harrison, Ed.

    1976-01-01

    This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

  6. Knee Pain during Strength Training Shortly following Fast-Track Total Knee Arthroplasty: A Cross-Sectional Study

    PubMed Central

    Bandholm, Thomas; Thorborg, Kristian; Lunn, Troels Haxholdt; Kehlet, Henrik; Jakobsen, Thomas Linding

    2014-01-01

    Background Loading and contraction failure (muscular exhaustion) are strength training variables known to influence neural activation of the exercising muscle in healthy subjects, which may help reduce neural inhibition of the quadriceps muscle following total knee arthroplasty (TKA). It is unknown how these exercise variables influence knee pain after TKA. Objective To investigate the effect of loading and contraction failure on knee pain during strength training, shortly following TKA. Design Cross-sectional study. Setting Consecutive sample of patients from the Copenhagen area, Denmark, receiving a TKA, between November 2012 and April 2013. Participants Seventeen patients, no more than 3 weeks after their TKA. Main outcome measures: In a randomized order, the patients performed 1 set of 4 standardized knee extensions, using relative loads of 8, 14, and 20 repetition maximum (RM), and ended with 1 single set to contraction failure (14 RM load). The individual loadings (kilograms) were determined during a familiarization session >72 hours prior. The patients rated their knee pain during each repetition, using a numerical rating scale (0–10). Results Two patients were lost to follow up. Knee pain increased with increasing load (20 RM: 3.1±2.0 points, 14 RM: 3.5±1.8 points, 8 RM: 4.3±2.5 points, P = 0.006), and repetitions to contraction failure (10% failure: 3.2±1.9 points, 100% failure: 5.4±1.6 points, P<0.001). Resting knee pain 60 seconds after the final repetition (2.7±2.4 points) was not different from that recorded before strength training (2.7±1.8 points, P = 0.88). Conclusion Both loading and repetitions performed to contraction failure during knee- extension strength-training, increased post-operative knee pain during strength training implemented shortly following TKA. However, only the increase in pain during repetitions to contraction failure exceeded that defined as clinically relevant, and was very short-lived. Trial Registration

  7. Synovial haemangioma of the knee joint: an unusual cause of knee pain in a 14-month old girl.

    PubMed

    Wen, D W; Tan, T J; Rasheed, S

    2016-06-01

    We report a histologically proven case of synovial haemangioma of the knee in a 14-month old girl who presented to the emergency department with an acute 1-day history of refusing to weight-bear on the right leg and a preceding 3-week history of a right knee lump. Physical examination revealed a non-tender, soft lump over the lateral infrapatellar region. Radiographs revealed a poorly defined soft tissue density over the infrapatellar fat pad and a suprapatellar joint effusion. Ultrasound was used to confirm the presence of a vascular soft tissue mass compatible with a synovial haemangioma within the infrapatellar fat pad which showed both intra-articular and extra-articular extension. There was good correlation of the ultrasound findings with magnetic resonance imaging (MRI), highlighting the potential clinical utility of ultrasound as an alternative imaging modality in establishing the pre-operative diagnosis and extent of a synovial haemangioma about the knee joint.

  8. [Arthroscopic treatment for osteoarthritic knee].

    PubMed

    Bloom, Shlomo; Lebel, David; Cohen, Eugen; Atar, Dan; Rath, Ehud

    2008-04-01

    Osteoarthritis (OA) is the leading cause of knee morbidity. Age and overweight are the main risk factors for development of knee OA. The majority of patients respond to conservative treatment. For those who don't, surgical treatment is the only alternative. Arthroscopic surgery for the osteoarthritic knee is a well known procedure. Recently, numerous publications addressed the advantages of arthroscopic treatment for this indication. Some of the publications concluded that arthroscopic treatment for knee OA equals placebo. Others found temporary relief of symptoms. Among special subgroup of patients, in which acute pain exacerbation, mechanical block or early OA, utilizing arthroscopic techniques revealed satisfactory results. In this review, we discuss the indications and contraindications for arthroscopic treatment of the osteoarthritic knee according to the latest literature.

  9. Anterior knee pain.

    PubMed

    LLopis, Eva; Padrón, Mario

    2007-04-01

    Anterior knee pain is a common complain in all ages athletes. It may be caused by a large variety of injuries. There is a continuum of diagnoses and most of the disorders are closely related. Repeated minor trauma and overuse play an important role for the development of lesions in Hoffa's pad, extensor mechanism, lateral and medial restrain structures or cartilage surface, however usually an increase or change of activity is referred. Although the direct relation of cartilage lesions, especially chondral, and pain is a subject of debate these lesions may be responsible of early osteoarthrosis and can determine athlete's prognosis. The anatomy and biomechanics of patellofemoral joint is complex and symptoms are often unspecific. Transient patellar dislocation has MR distinct features that provide evidence of prior dislocation and rules our complication. However, anterior knee pain more often is related to overuse and repeated minor trauma. Patella and quadriceps tendon have been also implicated in anterior knee pain, as well as lateral or medial restraint structures and Hoffa's pad. US and MR are excellent tools for the diagnosis of superficial tendons, the advantage of MR is that permits to rule out other sources of intraarticular derangements. Due to the complex anatomy and biomechanic of patellofemoral joint maltracking is not fully understood; plain films and CT allow the study of malalignment, new CT and MR kinematic studies have promising results but further studies are needed. Our purpose here is to describe how imaging techniques can be helpful in precisely defining the origin of the patient's complaint and thus improve understanding and management of these injuries.

  10. Evidence of isometric function of the flexor hallucis longus muscle in normal gait.

    PubMed

    Kirane, Y M; Michelson, J D; Sharkey, N A

    2008-01-01

    Studying mechanics of the muscles spanning multiple joints provides insights into intersegmental dynamics and movement coordination. Multiarticular muscles are thought to function at "near-isometric" lengths to transfer mechanical energy between the adjacent body segments. Flexor hallucis longus (FHL) is a multiarticular flexor of the great toe; however, its potential isometric function has received little attention. We used a robotic loading apparatus to investigate FHL mechanics during simulated walking in cadaver feet, and hypothesized that physiological force transmission across the foot can occur with isometric FHL function. The extrinsic foot tendons, stripped of the muscle fibers, were connected to computer-controlled linear actuators. The FHL activity was controlled using force-feedback (FC) based upon electromyographic data from healthy subjects, and subsequently, isometric positional feedback (PC), maintaining the FHL myotendinous junction stationary during simulated walking. Tendon forces and excursions were recorded, as were the strains within the first metatarsal. Forces in the metatarsal and metatarsophalangeal joint were derived from these strains. The FHL tendon excursion under FC was 6.57+/-3.13mm. The forces generated in the FHL tendon, metatarsal and metatarsophalangeal joint with the FHL under isometric PC were not significantly different in pattern from FC. These observations provide evidence that physiological forces could be generated along the great toe with isometric FHL function. A length servo mechanism such as the stretch reflex could likely control the isometric FHL function during in vivo locomotion; this could have interesting implications regarding the conditions of impaired stretch reflex such as spastic paresis and peripheral neuropathies.

  11. [Pathogenesis of knee osteoarthrist].

    PubMed

    Bennemann, M; Hönle, W; Simank, H G; Schuh, A

    2007-06-21

    More than 20% of the population of over 60-year olds suffers from degenerative joint diseases of the lower extremities. The cause of primary osteoarthritis of the knee is still unknown. A multifactorial genesis is presumed that includes genetic, nutritional, hormonal and age-related factors. On the other hand, secondary osteoarthritis is a sequela of predisposing factors. The most frequent are axial deformities, pre-existing conditions or injuries. Pre-osteoarthritis appears as dysplasias and dystopias (abnormal presentation) of the patella and axial misalignments, incongruities and joint damage after fractures. The result is the mechanical destruction of the cartilage that, in turn, initiates a vicious circle of further cartilage loss.

  12. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  13. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  14. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  15. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  16. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  17. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  18. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  19. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  20. 21 CFR 888.3570 - Knee joint femoral (hemi-knee) metallic uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint femoral (hemi-knee) metallic uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3570 Knee joint femoral (hemi-knee) metallic uncemented prosthesis. (a) Identification. A knee joint femoral...

  1. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  2. Biomechanical analysis of the human finger extensor mechanism during isometric pressing.

    PubMed

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints.

  3. Biomechanical Analysis of the Human Finger Extensor Mechanism during Isometric Pressing

    PubMed Central

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  4. Position sense at the human forearm after conditioning elbow muscles with isometric contractions.

    PubMed

    Tsay, A; Allen, T J; Proske, U

    2015-09-01

    These experiments were designed to test the idea that, in a forearm position-matching task, it is the difference in afferent signals coming from the antagonist muscles of the forearm that determines the perceived position of the arm. In one experiment, flexor and then extensor muscles of the reference arm were conditioned by isometric voluntary contractions while the arm was held at the test angle, approximately 45° from the horizontal. At the same time, indicator arm flexor muscles were contracted while the arm was flexed, or extensors were contracted while it was extended. After an indicator flexor contraction, during matching, subjects made large errors in the direction of flexion, by 9.3° relative to the reference arm and after an indicator extensor contraction by 7.4° in the direction of extension. In the second experiment, with reference muscles conditioned as before, slack was introduced in indicator muscles by a combination of muscle contraction and stretch. This was expected to lower levels of afferent activity in indicator muscles. The subsequent matching experiment yielded much smaller errors than before, 1.4° in the direction of flexion. In both experiments, signal levels coming from the reference arm remained the same and what changed was the level of indicator signal. The fact that matching errors were small when slack was introduced in indicator muscles supported the view that the signal coming from reference muscles was also small. It was concluded that the brain is concerned with the signal difference from the antagonist pair of each arm and with the total signal difference between the two arms.

  5. AGRICULTURAL EXTENSION.

    ERIC Educational Resources Information Center

    FARQUHAR, R.N.

    AUSTRALIAN AGRICULTURAL EXTENSION HAS LONG EMPHASIZED TECHNICAL ADVISORY SERVICE AT THE EXPENSE OF THE SOCIOECONOMIC ASPECTS OF FARM PRODUCTION AND FARM LIFE. ONLY IN TASMANIA HAS FARM MANAGEMENT BEEN STRESSED. DEMANDS FOR THE WHOLE-FARM APPROACH HAVE PRODUCED A TREND TOWARD GENERALISM FOR DISTRICT OFFICERS IN MOST STATES. THE FEDERAL GOVERNMENT,…

  6. Does bracing influence brain activity during knee movement: an fMRI study.

    PubMed

    Thijs, Youri; Vingerhoets, Guy; Pattyn, Els; Rombaut, Lies; Witvrouw, Erik

    2010-08-01

    Studies have shown that proprioceptive inputs during active and passive arm movements are processed in the primary and secondary somatosensory cortex and supplementary motor area of the brain. At which level of the central nervous system proprioceptive signals coming from the knee are regulated remains to be elucidated. In order to investigate whether there is a detectable difference in brain activity when various proprioceptive inputs are exerted at the knee, functional magnetic resonance imaging (fMRI) was used. fMRI in 13 healthy, right leg-dominant female volunteers compared brain activation during flexion-extension movements of the right knee under three different conditions: with application of a tight knee brace, with application of a moderate tight knee sleeve, and without application of a brace or sleeve. Brain activation was detected in the primary sensorimotor cortex (left and right paracentral lobule) and in the left superior parietal lobule of the brain. There was a significantly higher level of brain activation with the application of the brace and sleeve, respectively, compared to the condition without a brace or sleeve. A significantly higher cortical activation was also seen when comparing the braced condition with the condition when a sleeve was applied. The results suggest that peripheral proprioceptive input to the knee joint by means of a brace or sleeve seems to influence brain activity during knee movement. The results of this study also show that the intensity of brain activation during knee movement can be influenced by the intensity of proprioceptive stimulation at the joint.

  7. Neglected surgically intervened bilateral congenital dislocation of knee in an adolescent

    PubMed Central

    Kumar, Jaswant; Dhammi, Ish Kumar; Jain, Anil K

    2014-01-01

    Neglected bilateral congenital dislocation of knee is unusual. A 12 year old boy presented with inability to walk due to buckling of the knee. The symptoms were present since the child learnt walking. He preferred not to walk. Bilateral supracondylar femoral osteotomy was done at the age of 6 years. Patient had a fixed flexion deformity of both knees, 30° in the right (range of flexion from 30° to 45°) and 45° fixed flexion deformity in left knee respectively (range of flexion from 45° to 65°) when presented to us. The radiological examination revealed bilateral congenital dislocation of knee (CDK). No syndromic association was observed. He was planned for staged treatment. In stage I, the knee joints were distracted by Ilizarov ring fixators and this was followed by open reduction of both the knee joints in stage II. A bilateral supracondylar extension osteotomy was done 18 months after the previous surgery (stage III). The final followup visit at 4 years the patient presented with range of motion 5-100° and 5-80° on the right and left knee respectively with good functional outcome. The case is reported in view of lack of treatment guidelines for long standing neglected CDK in an adolescent child. PMID:24600070

  8. Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

    PubMed Central

    De Moudt, Sofie; Leloup, Arthur; Van Hove, Cor; De Meyer, Guido; Fransen, Paul

    2017-01-01

    Most vaso-reactive studies in mouse aortic segments are performed in isometric conditions and at an optimal preload, which is the preload corresponding to a maximal contraction by non-receptor or receptor-mediated stimulation. In general, this optimal preload ranges from about 1.2 to 8.0 mN/mm, which according to Laplace's law roughly correlates with transmural pressures of 10–65 mmHg. For physiologic transmural pressures around 100 mmHg, preloads of 15.0 mN/mm should be implemented. The present study aimed to compare vascular reactivity of 2 mm mouse (C57Bl6) aortic segments preloaded at optimal (8.0 mN/mm) vs. (patho) physiological (10.0–32.5 mN/mm) preload. Voltage-dependent contractions of aortic segments, induced by increasing extracellular K+, and contractions by α1-adrenergic stimulation with phenylephrine (PE) were studied at these preloads in the absence and presence of L-NAME to inhibit basal release of NO from endothelial cells (EC). In the absence of basal NO release and with higher than optimal preload, contractions evoked by depolarization or PE were attenuated, whereas in the presence of basal release of NO PE-, but not depolarization-induced contractions were preload-independent. Phasic contractions by PE, as measured in the absence of external Ca2+, were decreased at higher than optimal preload suggestive for a lower contractile SR Ca2+ content at physiological preload. Further, in the presence of external Ca2+, contractions by Ca2+ influx via voltage-dependent Ca2+ channels were preload-independent, whereas non-selective cation channel-mediated contractions were increased. The latter contractions were very sensitive to the basal release of NO, which itself seemed to be preload-independent. Relaxation by endogenous NO (acetylcholine) of aortic segments pre-contracted with PE was preload-independent, whereas relaxation by exogenous NO (diethylamine NONOate) displayed higher sensitivity at high preload. Results indicated that stretching aortic

  9. Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait

    PubMed Central

    Samaan, Michael A.; Teng, Hsiang-Ling; Kumar, Deepak; Lee, Sonia; Link, Thomas; Majumdar, Sharmila; Souza, Richard B.

    2015-01-01

    Background Patients with acetabular cartilage defects reported increased pain and disability compared to those without acetabular cartilage defects. The specific effects of acetabular cartilage defects on lower extremity coordination patterns are unclear. The purpose of this study was to determine hip and knee joint coordination variability during gait in those with and without acetabular cartilage defects. Methods A combined approach, consisting of a semi-quantitative MRI-based quantification method and vector coding, was used to assess hip and knee joint coordination variability during gait in those with and without acetabular cartilage lesions. Findings The coordination variability of the hip flexion-extension/knee rotation, hip abduction-adduction/knee rotation and hip rotation/knee rotation joint couplings were reduced in the acetabular lesion group compared to the control group during loading response of the gait cycle. The lesion group demonstrated increased variability in the hip flexion-extension/knee rotation and hip abduction-adduction/knee rotation joint couplings, compared to the control group, during the terminal stance/pre-swing phase of gait. Interpretation Reduced variability during loading response in the lesion group may suggest reduced movement strategies and a possible compensation mechanism for lower extremity instability during this phase of the gait cycle. During terminal stance/pre-swing, a larger variability in the lesion group may suggest increased movement strategies and represent a compensation or pain avoidance mechanism caused by the load applied to the hip joint. PMID:26298706

  10. Giant Angioleiomyoma of Knee Presenting as Painless Ulcer: The First Case Report.

    PubMed

    Gupta, Souradip; Chattopadhyay, Debarati; Dhiman, Pratibha; Gupta, Sandipan

    2015-01-01

    Angioleiomyomas are benign tumors originating in the vascular smooth muscle. The tumor typically presents as painful, solitary, small (<2 cm), slow growing, subcutaneous nodule. Angioleiomyoma of the knee is rare, and only few cases have been reported so far. We have described herein a giant angioleiomyoma of the knee presenting as a painless ulcer in a 22-year-old man. There was no intra-articular extension of the tumor, and total excision was curative. This is the first case report of giant angioleiomyoma of the knee as well as the first case report of angioleiomyoma presenting as a painless ulcerative lesion.

  11. Exercise for knee osteoarthritis.

    PubMed

    Baker, K; McAlindon, T

    2000-09-01

    Adverse outcomes in knee osteoarthritis include pain, loss of function, and disability. These outcomes can have devastating effects on the quality of life of those suffering from the disease. Treatments have generally targeted pain, assuming that disability would improve as a direct result of improvements in pain. However, there is evidence to suggest that determinants of pain and disability differ. In general, treatments have been more successful at decreasing pain rather than disability. Many of the factors that lead to disability can be improved with exercise. Exercise, both aerobic and strength training, have been examined as treatments for knee osteoarthritis, with considerable variability in the results. The variability between studies may be due to differences in study design, exercise protocols, and participants in the studies. Although there is variability among studies, it is notable that a majority of the studies had a positive effect on pain and or disability. The mechanism of exercise remains unclear and merits future studies to better define a concise, clear exercise protocol that may have the potential for a public health intervention.

  12. Comparison of EMG activity on abdominal muscles during plank exercise with unilateral and bilateral additional isometric hip adduction.

    PubMed

    Kim, Soo-Yong; Kang, Min-Hyeok; Kim, Eui-Ryong; Jung, In-Gui; Seo, Eun-Young; Oh, Jae-Seop

    2016-10-01

    The aim of this study was to investigate the effects of additional isometric hip adduction during the plank exercise on the abdominal muscles. Twenty healthy young men participated in this study. Surface electromyography (EMG) was used to monitor the activity of the bilateral rectus abdominis (RA), the internal oblique (IO), and the external oblique (EO) muscles. The participants performed three types of plank exercise; the standard plank exercise, the plank exercise with bilateral isometric hip adduction, and the plank exercise with unilateral isometric hip adduction. All abdominal muscle activity was significantly increased during the plank exercise combined with the bilateral and unilateral isometric hip adduction compared with the standard plank exercise (p<0.05). Bilateral IO, EO, and left RA muscle activity was significantly increased during the unilateral isometric hip adduction compared with the bilateral isometric hip adduction (p<0.05). These findings suggest that additional isometric hip adduction during the plank exercise could be a useful method to enhance abdominal muscle activity. In particular, the unilateral isometric hip adduction is a more beneficial exercise than the bilateral isometric hip adduction.

  13. The effect of shortening history on isometric and dynamic muscle function.

    PubMed

    McDaniel, John; Elmer, Steven J; Martin, James C

    2010-03-03

    Despite numerous reports on isometric force depression, few reports have quantified force depression during active muscle shortening (dynamic force depression). The purpose of this investigation was to determine the influence of shortening history on isometric force following active shortening, force during isokinetic shortening, and velocity during isotonic shortening. The soleus muscles of four cats were subjected to a series of isokinetic contractions at three shortening velocities and isotonic contractions under three loads. Muscle excursions initiated from three different muscle lengths but terminated at a constant length. Isometric force produced subsequent to active shortening, and force or shortening velocity produced at a specific muscle length during shortening, were compared across all three conditions. Results indicated that shortening history altered isometric force by up to 5%, force during isokinetic shortening up to 30% and shortening velocity during isotonic contractions by up to 63%. Furthermore, there was a load by excursion interaction during isotonic contractions such that excursion had the most influence on shortening velocity when the loads were the greatest. There was not a velocity by excursion interaction during isokinetic contractions. Isokinetic and isotonic power-velocity relationships displayed a downward shift in power as excursions increased. Thus, to discuss force depression based on differences in isometric force subsequent to active shortening may underestimate its importance during dynamic contractions. The presence of dynamic force depression should be realized in sport performance, motor control modeling and when controlling paralyzed limbs through artificial stimulation.

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

    PubMed

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

    2012-07-01

    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.

  15. New Generation Lockable Knee Brace

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A knee brace that uses Space Shuttle propulsion technology has moved a step closer to being available to help knee injury and stroke patients and may possibly benefit patients with birth defects, spinal cord injuries, and post-polio conditions. After years of hard work, inventors at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, have turned over the final design and prototype to industry partners at Horton's Orthotic Lab in Little Rock, Arkansas for further clinical testing. The device, called the Selectively Lockable Knee Brace, may mean faster, less painful rehabilitation for patients by allowing the knee to move when weight is not on the heel. Devices currently on the market lock the knee in a rigid, straight-leg position, or allow continuous free motion. The knee brace is just one example of how space technology is being used to improve the lives of people on Earth. NASA's MSFC inventors Michael Shadoan and Neill Myers are space propulsion engineers who use the same mechanisms and materials to build systems for rockets that they used to design and develop the knee brace.

  16. Physiotherapy management of knee osteoarthritis.

    PubMed

    Page, Carolyn J; Hinman, Rana S; Bennell, Kim L

    2011-05-01

    Knee osteoarthritis (OA) is a prevalent chronic joint disease causing pain and disability. Physiotherapy, which encompasses a number of modalities, is a non-invasive treatment option in the management of OA. This review summarizes the evidence for commonly used physiotherapy interventions. There is strong evidence to show short-term beneficial effects of exercise on pain and function, although the type of exercise does not seem to influence treatment outcome. Delivery modes, including individual, group or home exercise are all effective, although therapist contact may improve benefits. Attention to improving adherence to exercise is needed to maximize outcomes in the longer-term. Knee taping applied with the aim of realigning the patella and unloading soft tissues can reduce pain. There is also evidence to support the use of knee braces in people with knee OA. Biomechanical studies show that lateral wedge shoe insoles reduce knee load but clinical trials do not support symptomatic benefits. Recent studies suggest individual shoe characteristics also affect knee load and there is current interest in the effect of modified shoe designs. Manual therapy, while not to be used as a stand-alone treatment, may be beneficial. In summary, although the research is not equivocal, there is sufficient evidence to indicate that physiotherapy interventions can reduce pain and improve function in those with knee OA.

  17. Sensitivity of knee soft-tissues to surgical technique in total knee arthroplasty.

    PubMed

    Schirm, Andreas C; Jeffcote, Benjamin O; Nicholls, Rochelle L; Jakob, Hilaire; Kuster, Markus S

    2011-06-01

    Restricted range of motion and excessive laxity are both potential complications of total knee arthroplasty (TKA). During TKA surgery, the surgeon is frequently faced with the question of how tightly to implant the prosthesis. The most common method of altering implantation tightness is to vary the thickness of the polyethylene inlay after the bone cuts have been made and the trial components inserted. We have sought to quantify how altering the polyethylene thickness may affect post-operative soft tissue tension for a range of prosthetic designs. Four different prosthetic designs were implanted into fresh-frozen cadaveric knee joints. All four designs were implanted in the standard manner, with a 100 Newton distraction force used to set soft tissue balance. The tibiofemoral force was then recorded at 15° intervals throughout the passive flexion range. After the standard implantation of each prosthesis, the tibial component was raised or lowered to mimic increasing and decreasing the polyethylene thickness by 2mm and the force measurements repeated. Tibiofemoral force in extension correlated with implantation tightness for all prosthesis designs. Between 15° and 90° of knee flexion, all four designs were insensitive to changes in implantation tightness. Beyond 90° the effect was more notable in rotating platform mobile-bearing and cruciate-retaining prostheses than in posterior-stabilised mobile-bearing designs. The findings of this research may be useful in assisting surgical decision-making during the implantation of TKA prostheses.

  18. A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise

    PubMed Central

    Kang, Jeong-Il; Park, Joon-Su; Choi, Hyun; Jeong, Dae-Keun; Kwon, Hye-Min; Moon, Young-Jun

    2017-01-01

    [Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome. PMID:28210036

  19. RELATIONSHIP BETWEEN BIOMECHANICAL ASYMMETRIES DURING A STEP UP AND OVER TASK AND STAIR CLIMBING AFTER TOTAL KNEE ARTHROPLASTY

    PubMed Central

    Pozzi, Federico; Snyder-Mackler, Lynn; Zeni, Joseph

    2014-01-01

    Background Patients six months after total knee arthroplasty demonstrate movement asymmetries and functional deficits, which may be related to poor functional performance. The aims of this study were to 1) compare biomechanical variables between subjects 6 months after total knee arthroplasty and an agematched healthy control group during a step up and over task and 2) determine the relationship between quadriceps strength, movement patterns and stair climbing performance. Methods Twenty patients 6 months following unilateral total knee arthroplasty and twenty healthy controls were enrolled. Participants completed questionnaires, isometric quadriceps strength testing and performance based tests to quantify functional performance. Motion analysis was performed during a step up and over task. Functional and biomechanical variables were analyzed using a 2×2 ANOVA. The symmetry ratios (operated/non-operated limb *100) for biomechanical variables were analyzed using independent t-tests. Pearson correlations were performed to determine the relationships between biomechanical variables, strength and stair climbing performance. Findings In the TKA group, subjects had lower peak moments, power and sagittal plane excursion in the operated knee compared to the contralateral knee (p < .05), while the hip on the operated side had greater power generation (p = .014). Compared to the control group, all symmetry ratios were significantly lower in the surgical group (p < .05). Stair climbing time was correlated with quadriceps strength of the operated limb (R=−0.762, p<0.001). Interpretation Individuals 6 months after total knee arthroplasty had worse performance with respect to biomechanics, quadriceps strength, and performance-based tests. Biomechanical asymmetries after TKA reduce the demand on the operated knee and increase reliance on the contralateral limb and ipsilateral hip. PMID:25467765

  20. A study on muscle activity and ratio of the knee extensor depending on the types of squat exercise.

    PubMed

    Kang, Jeong-Il; Park, Joon-Su; Choi, Hyun; Jeong, Dae-Keun; Kwon, Hye-Min; Moon, Young-Jun

    2017-01-01

    [Purpose] For preventing the patellofemoral pain syndrome, this study aims to suggest a proper squat method, which presents selective muscle activity of Vastus Medialis Oblique and muscle activity ratios of Vastus Medialis Oblique/Vastus Lateralis by applying squat that is a representative weight bearing exercise method in various ways depending on the surface conditions and knee bending angles. [Subjects and Methods] An isometric squat that was accompanied by hip adduction, depending on the surface condition and the knee joint flexion angle, was performed by 24 healthy students. The muscle activity and the ratio of muscle activity were measured. [Results] In a comparison of muscle activity depending on the knee joint flexion angle on a weight-bearing surface, the vastus medialis oblique showed a significant difference at 15° and 60°. Meanwhile, in a comparison of the muscle activity ratio between the vastus medialis oblique and the vastus lateralis depending on the knee joint flexion angle on a weight-bearing surface, significant differences were observed at 15° and 60°. [Conclusion] An efficient squat exercise posture for preventing the patellofemoral pain syndrome is to increase the knee joint bending angle on a stable surface. But it would be efficient for patients with difficulties in bending the knee joint to keep a knee joint bending angle of 15 degrees or less on an unstable surface. It is considered that in future, diverse studies on selective Vastus Medialis Oblique strengthening exercise methods would be needed after applying them to patients with the patellofemoral pain syndrome.

  1. Preoperative physical performance predictors of self-reported physical function and quality of life in patients scheduled for total knee arthroplasty

    PubMed Central

    Hyun, Chul Woong; Kim, Bo Ryun; Han, Eun Young; Kim, Sang Rim

    2016-01-01

    [Purpose] To determine the preoperative self-reported and performance-based physical function of patients with end-stage knee osteoarthritis who awaited total knee arthroplasty. The preoperative physical performance factors that predicted self-reported physical function and quality of life were also identified. [Subjects and Methods] All adults with end-stage knee osteoarthritis awaiting surgery were enrolled. Before surgery, self-reported disease-specific physical function and self-reported pain were measured using the Western Ontario McMaster Universities Osteoarthritis Index, self-reported quality of life was measured using the EuroQOL five dimensions questionnaire, and physical performance tests were performed, the 6 minute walk test, the timed up-and-go test, instrumental gait analysis, and measurement of isometric knee flexor and extensor strength of the surgical and nonsurgical knees. [Results] In total, 55 adults (49 females; 73.3 ± 6.1 years) were included. This study showed that several preoperative self-reported and physical performance factors were predictive of self-reported physical function and quality of life. [Conclusion] In patients with end-stage knee osteoarthritis, preoperative pain and dynamic balance ability were the most powerful predictors of self-reported physical function. Preoperative pain and exercise tolerance were the most powerful predictors of quality of life. Preoperative rehabilitation strategies that focus on dynamic balance, aerobic, and resistance exercises may improve surgical outcomes. PMID:27942153

  2. Three Point Extension Splint To Treat Flexion Contractures About Limb Synovial Hinge Joints.

    DTIC Science & Technology

    rehabilitating flexion contractures caused by soft tissue injury. More particularly, the invention relates to a three point extension splint to treat flexion contractures about the knee, elbow and/or finger.

  3. Enhanced knee joint function due to accelerated rehabilitation exercise after anterior cruciate ligament reconstruction surgery in Korean male high school soccer players

    PubMed Central

    Lee, Myungchun; Sung, Dong Jun; Lee, Joohyung; Oh, Inyoung; Kim, Sojung; Kim, Seungho; Kim, Jooyoung

    2016-01-01

    This study was conducted on Korean male high school soccer players who underwent anterior cruciate ligament reconstruction (ACLR) to identify the effects of an accelerated rehabilitation exercise (ARE) program on knee joint isometric strength, thigh circumference, Lysholm score, and active balance agility. We assigned eight test participants each to a physical therapy group (PTG) and an accelerated rehabilitation exercise group (AREG), and compared differences between the groups. Both the PTG and AREG showed significant increases in 30° away and 60° toward isometric strength after treatment. In addition, significant differences were observed in these strength tests between the two groups. Both groups also showed significant increases in thigh circumference, Lysholm score, and active balance agility after treatment, but no significant differences were observed between the two groups. We conclude that the ARE treatment was more effective for improving isometric strength of the knee joint than that of physical therapy, and that an active rehabilitation exercise program after ACLR had positive effects on recovery performance of patients with an ACL injury and their return to the playing field. PMID:26933657

  4. BV weak solutions to Gauss-Codazzi system for isometric immersions

    NASA Astrophysics Data System (ADS)

    Christoforou, Cleopatra

    The isometric immersion problem for surfaces embedded into R is studied via the fluid dynamic framework introduced in Chen et al. (2010) [6] as a system of balance laws of mixed-type. The techniques developed in the theory of weak solutions of bounded variation in continuum physics are employed to deal with the isometric immersions in the setting of differential geometry. The so-called BV framework is formed that establishes convergence of approximate solutions of bounded variation to the Gauss-Codazzi system and yields the C isometric realization of two-dimensional surfaces into R. Local and global existence results are established for weak solutions of small bounded variation to the Gauss-Codazzi system for negatively curved surfaces that admit equilibrium configurations. As an application, the case of catenoidal shell of revolution is provided.

  5. Test-retest reliability of isometric shoulder muscle strength measurement with a handheld dynamometer and belt.

    PubMed

    Katoh, Munenori

    2015-06-01

    [Purpose] The aim of this study was to develop a method of measuring isometric shoulder joint muscle strength using a handheld dynamometer with a belt and investigate its test-retest reliability. [Subjects] The subjects comprised 40 healthy adults. [Methods] Six types of isometric shoulder muscle strength were measured twice, and reliability was assessed. [Results] The intraclass correlation coefficient (1, 1) values ranged from 0.976 to 0.902. The result of a Bland-Altman analysis showed differences in the types of errors between measurement items. [Conclusion] The relative reliability of isometric shoulder muscle measurement using a handheld dynamometer with a belt was high. However, analysis of absolute reliability revealed errors that may affect interpretation of values; therefore, it was considered that adapting the greater of two measurement values is appropriate.

  6. Non-rigid registration of 3D point clouds under isometric deformation

    NASA Astrophysics Data System (ADS)

    Ge, Xuming

    2016-11-01

    An algorithm for pairwise non-rigid registration of 3D point clouds is presented in the specific context of isometric deformations. The critical step is registration of point clouds at different epochs captured from an isometric deformation surface within overlapping regions. Based on characteristics invariant under isometric deformation, a variant of the four-point congruent sets algorithm is applied to generate correspondences between two deformed point clouds, and subsequently a RANSAC framework is used to complete cluster extraction in preparation for global optimal alignment. Examples are presented and the results compared with existing approaches to demonstrate the two main contributions of the technique: a success rate for generating true correspondences of 90% and a root mean square error after final registration of 2-3 mm.

  7. Developmental Changes in Hemodynamic Responses and Cardiovagal Modulation during Isometric Handgrip Exercise

    PubMed Central

    Goulopoulou, Styliani; Fernhall, Bo; Kanaley, Jill A.

    2010-01-01

    The purpose of this study was to examine differences in pressor response and cardiovagal modulation during isometric handgrip exercise (IHG) between children and adults. Beat-to-beat heart rate (HR) and blood pressure were measured in 23 prepubertal children and 23 adults at baseline and during IHG. Cardiovagal modulation was quantified by analysis of HR variability. Mean arterial pressure responses to IHG were greater in adults compared to children (P < .05) whereas there were no group differences in HR responses (P > .05). Children had a greater reduction in cardiovagal modulation in response to IHG compared to adults (P < .05). Changes in mean arterial pressure during IHG were correlated with baseline cardiovagal modulation and force produced during isometric contraction (P < .05). In conclusion, differences in pressor reflex response between children and adults cannot be solely explained by differences in autonomic modulation and appear to be associated with factors contributing to the force produced during isometric contraction. PMID:20862202

  8. Three-dimensional geometrical changes of the human tibialis anterior muscle and its central aponeurosis measured with three-dimensional ultrasound during isometric contractions

    PubMed Central

    Cresswell, Andrew G.; Lichtwark, Glen A.

    2016-01-01

    Background. Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D) muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the duration of an in vivo scan. Although two-dimensional ultrasound imaging is useful for measuring local muscle deformations, assumptions must be made about global muscle shape changes, which could lead to errors in fully understanding the mechanical behaviour of muscle and its surrounding connective tissues, such as aponeurosis. Therefore, the aims of this investigation were (a) to determine the intra-session reliability of a novel 3D ultrasound (3DUS) imaging method for measuring in vivo human muscle and aponeurosis deformations and (b) to examine how contraction intensity influences in vivo human muscle and aponeurosis strains during isometric contractions. Methods. Participants (n = 12) were seated in a reclined position with their left knee extended and ankle at 90° and performed isometric dorsiflexion contractions up to 50% of maximal voluntary contraction. 3DUS scans of the tibialis anterior (TA) muscle belly were performed during the contractions and at rest to assess muscle volume, muscle length, muscle cross-sectional area, muscle thickness and width, fascicle length and pennation angle, and central aponeurosis width and length. The 3DUS scan involved synchronous B-mode ultrasound imaging and 3D motion capture of the position and orientation of the ultrasound transducer, while successive cross-sectional slices were captured by sweeping the transducer along the muscle. Results. 3DUS was shown to be highly reliable across measures of muscle volume, muscle length, fascicle length and central aponeurosis length (ICC ≥ 0.98, CV < 1%). The TA remained isovolumetric

  9. Lessons Learned from Selective Soft-Tissue Release for Gap Balancing in Primary Total Knee Arthroplasty: An Analysis of 1216 Consecutive Total Knee Arthroplasties

    PubMed Central

    Peters, Christopher L.; Jimenez, Chris; Erickson, Jill; Anderson, Mike B.; Pelt, Christopher E.

    2013-01-01

    Background: Soft-tissue releases are commonly necessary to achieve symmetrical flexion and extension gaps in primary total knee arthroplasty performed with a measured resection technique. We reviewed the frequency of required releases according to preoperative alignment and the clinical and radiographic results; associations with failure, reoperations, and complications are presented. Methods: We reviewed 1216 knees that underwent primary total knee arthroplasty from 2004 to 2009; 774 (64%) were in female patients and 442 (36%), in male patients. In the coronal plane, 855 knees had preoperative varus deformity, 123 were neutral, and 238 had valgus deformity. The mean age at the time of the index procedure was 62.7 years (range, twenty-three to ninety-four years), and the mean body mass index was 32.7 kg/m2 (range, 17.4 to 87.9 kg/m2). Clinical outcomes included the Knee Society Score (KSS), implant failure, reoperation, and complications. Radiographs were analyzed for component alignment. Results: The only difference in the total KSS was found at the time of final follow-up between valgus knees with zero releases (total KSS = 178) and those with one or two releases (KSS = 160, p = 0.026). Overall, 407 knees (33.5%) required zero releases, 686 (56.4%) required oneor two releases, and 123 (10.1%) required three or more releases. Among varus knees, 37% required zero releases, 55% required one or two releases, and 7.5% required three or more releases. Among neutral knees, 39% required zero releases, 55% required one or two releases, and 5.7% required three or more releases. Only 17% of valgus knees required zero releases whereas 61% required one or two releases and 21.8% required three or more releases. Valgus knees required more releases than neutral or varus knees did (p < 0.001). Conclusions: Selective soft-tissue release for gap balancing in primary total knee arthroplasty is an effective technique that produced excellent clinical and radiographic results

  10. Higher Neuromuscular Manifestations of Fatigue in Dynamic than Isometric Pull-Up Tasks in Rock Climbers

    PubMed Central

    Boccia, Gennaro; Pizzigalli, Luisa; Formicola, Donato; Ivaldi, Marco; Rainoldi, Alberto

    2015-01-01

    Neuromuscular assessment of rock climbers has been mainly focused on forearm muscles in the literature. We aimed to extend the body of knowledge investigating on two other upper limb muscles during sport-specific activities in nine male rock climbers. We assessed neuromuscular manifestations of fatigue recording surface electromyographic signals from brachioradialis and teres major muscles, using multi-channel electrode arrays. Participants performed two tasks until volitional exhaustion: a sequence of dynamic pull-ups and an isometric contraction sustaining the body at half-way of a pull-up (with the elbows flexed at 90°). The tasks were performed in randomized order with 10 minutes of rest in between. The normalized rate of change of muscle fiber conduction velocity was calculated as the index of fatigue. The time-to-task failure was significantly shorter in the dynamic (31 ±10 s) than isometric contraction (59 ±19 s). The rate of decrease of muscle fiber conduction velocity was found steeper in the dynamic than isometric task both in brachioradialis (isometric: −0.2 ±0.1%/s; dynamic: −1.2 ±0.6%/s) and teres major muscles (isometric: −0.4±0.3%/s; dynamic: −1.8±0.7%/s). The main finding was that a sequence of dynamic pull-ups lead to higher fatigue than sustaining the body weight in an isometric condition at half-way of a pull-up. Furthermore, we confirmed the possibility to properly record physiological CV estimates from two muscles, which had never been studied before in rock climbing, in highly dynamic contractions. PMID:26557188

  11. Higher Neuromuscular Manifestations of Fatigue in Dynamic than Isometric Pull-Up Tasks in Rock Climbers.

    PubMed

    Boccia, Gennaro; Pizzigalli, Luisa; Formicola, Donato; Ivaldi, Marco; Rainoldi, Alberto

    2015-09-29

    Neuromuscular assessment of rock climbers has been mainly focused on forearm muscles in the literature. We aimed to extend the body of knowledge investigating on two other upper limb muscles during sport-specific activities in nine male rock climbers. We assessed neuromuscular manifestations of fatigue recording surface electromyographic signals from brachioradialis and teres major muscles, using multi-channel electrode arrays. Participants performed two tasks until volitional exhaustion: a sequence of dynamic pull-ups and an isometric contraction sustaining the body at half-way of a pull-up (with the elbows flexed at 90°). The tasks were performed in randomized order with 10 minutes of rest in between. The normalized rate of change of muscle fiber conduction velocity was calculated as the index of fatigue. The time-to-task failure was significantly shorter in the dynamic (31 ±10 s) than isometric contraction (59 ±19 s). The rate of decrease of muscle fiber conduction velocity was found steeper in the dynamic than isometric task both in brachioradialis (isometric: -0.2 ±0.1%/s; dynamic: -1.2 ±0.6%/s) and teres major muscles (isometric: -0.4±0.3%/s; dynamic: -1.8±0.7%/s). The main finding was that a sequence of dynamic pull-ups lead to higher fatigue than sustaining the body weight in an isometric condition at half-way of a pull-up. Furthermore, we confirmed the possibility to properly record physiological CV estimates from two muscles, which had never been studied before in rock climbing, in highly dynamic contractions.

  12. Structural features of cross-bridges in isometrically contracting skeletal muscle.

    PubMed

    Kraft, Theresia; Mattei, Thomas; Radocaj, Ante; Piep, Birgit; Nocula, Christoph; Furch, Markus; Brenner, Bernhard

    2002-05-01

    Two-dimensional x-ray diffraction was used to investigate structural features of cross-bridges that generate force in isometrically contracting skeletal muscle. Diffraction patterns were recorded from arrays of single, chemically skinned rabbit psoas muscle fibers during isometric force generation, under relaxation, and in rigor. In isometric contraction, a rather prominent intensification of the actin layer lines at 5.9 and 5.1 nm and of the first actin layer line at 37 nm was found compared with those under relaxing conditions. Surprisingly, during isometric contraction, the intensity profile of the 5.9-nm actin layer line was shifted toward the meridian, but the resulting intensity profile was different from that observed in rigor. We particularly addressed the question whether the differences seen between rigor and active contraction might be due to a rigor-like configuration of both myosin heads in the absence of nucleotide (rigor), whereas during active contraction only one head of each myosin molecule is in a rigor-like configuration and the second head is weakly bound. To investigate this question, we created different mixtures of weak binding myosin heads and rigor-like actomyosin complexes by titrating MgATPgammaS at saturating [Ca2+] into arrays of single muscle fibers. The resulting diffraction patterns were different in several respects from patterns recorded under isometric contraction, particularly in the intensity distribution along the 5.9-nm actin layer line. This result indicates that cross-bridges present during isometric force generation are not simply a mixture of weakly bound and single-headed rigor-like complexes but are rather distinctly different from the rigor-like cross-bridge. Experiments with myosin-S1 and truncated S1 (motor domain) support the idea that for a force generating cross-bridge, disorder due to elastic distortion might involve a larger part of the myosin head than for a nucleotide free, rigor cross-bridge.

  13. Relationship between force-time and velocity-time characteristics of dynamic and isometric muscle actions.

    PubMed

    Khamoui, Andy V; Brown, Lee E; Nguyen, Diamond; Uribe, Brandon P; Coburn, Jared W; Noffal, Guillermo J; Tran, Tai

    2011-01-01

    Previous research has investigated the force-time curve characteristics of isometric and dynamic muscle actions; however, few studies have addressed their relationship to dynamic exercise velocity-time variables. The purpose of this study was to investigate relationships between velocity-time characteristics (high pull and vertical jump peak velocity and rate of velocity development [HPPV, HPRVD, VJPV, VJRVD]), force-time characteristics (isometric peak force [IsoPF], body mass adjusted isometric peak force [IsoPF/BM], isometric rate of force development at different millisecond windows [IsoRFD50-250], dynamic peak force [HPPF], body mass adjusted dynamic peak force [HPPF/BM]), and vertical jump height (VJHeight). Nineteen recreationally trained men (age 23.89 ± 2.92 yr; height 176.32 ± 7.06 cm; mass 78.76 ± 16.50 kg) completed 2 testing sessions. The first session consisted of 3 isometric mid-thigh pulls on a force plate with each repetition held for 3 seconds. On the second testing session, subjects completed 3 dynamic mid-thigh high pulls with 30% IsoPF followed by 3 vertical jumps on a force plate. The HPRVD correlated with IsoRFD50 (r = 0.52) and IsoRFD100 (r = 0.49). The HPPV correlated with IsoPF/BM (r = -0.60), IsoRFD50 (r = 0.56), and IsoRFD100 (r = 0.56). The VJHeight correlated with IsoPF/BM (r = 0.61), whereas VJPV correlated with IsoPF/BM (r = 0.62). These correlations suggest that explosive isometric force production within 50 to 100 milliseconds may influence the ability to accelerate an implement or body and attain high velocity, albeit in a moderate fashion. In addition, body mass adjusted strength may positively influence vertical jump parameters.

  14. Multiple needle puncturing: balancing the varus knee.

    PubMed

    Bellemans, Johan

    2011-09-09

    The so-called "pie crusting" technique using multiple stab incisions is a well-established procedure for correcting tightness of the iliotibial band in the valgus knee. It is, however, not applicable for balancing the medial side in varus knees because of the risk for iatrogenic transsection of the medial collateral ligament (MCL). This article presents our experience with a safer alternative and minimally invasive technique for medial soft tissue balancing, where we make multiple punctures in the MCL using a 19-gauge needle to progressively stretch the MCL until a correct ligament balance is achieved. Our technique requires minimal to no additional soft tissue dissection and can even be performed percutaneously when necessary. This technique, therefore, does not impact the length of the skin or soft tissue incisions. We analyzed 61 cases with varus deformity that were intraoperatively treated using this technique. In 4 other cases, the technique was used as a percutaneous procedure to correct postoperative medial tightness that caused persistent pain on the medial side. The procedure was considered successful when a 2- to 4-mm mediolateral joint line opening was obtained in extension and 2 to 6 mm in flexion. In 62 cases (95%), a progressive correction of medial tightness was achieved according to the above-described criteria. Three cases were overreleased and required compensatory release of the lateral structures and use of a thicker insert. Based on these results, we consider needle puncturing an effective and safe technique for progressive correction of MCL tightness during minimally invasive total knee arthroplasty.

  15. Predicting Functional Performance and Range of Motion Outcomes After Total Knee Arthroplasty

    PubMed Central

    Bade, Michael J.; Kittelson, John M.; Kohrt, Wendy M.; Stevens-Lapsley, Jennifer E.

    2015-01-01

    Objective The aim of this study was to assess the predictive value of functional performance and range of motion measures on outcomes after total knee arthroplasty. Design This is a secondary analysis of two pooled prospective randomized controlled trials. Sixty-four subjects (32 men and 32 women) with end-stage knee osteoarthritis scheduled to undergo primary total knee arthroplasty were enrolled. Active knee flexion and extension range of motion, Timed Up and Go (TUG) test time, and 6-min walk test distance were assessed. Results Preoperative measures of knee flexion and extension were predictive of long-term flexion (β = 0.44, P < 0.001) and extension (β = 0.46, P < 0.001). Acute measures of knee flexion and extension were not predictive of long-term flexion (β= 0.09, P = 0.26) or extension (β = 0.04, P = 0.76). Preoperative TUG performance was predictive of long-term 6-min walk performance (β = −21, P < 0.001). Acute TUG performance was predictive of long-term functional performance on the 6-min walk test, after adjusting for the effects of sex and age (P = 0.02); however, once adjusted for preoperative TUG performance, acute TUG was no longer related to long-term 6-min walk performance (P = 0.65). Conclusions Acute postoperative measures of knee range of motion are of limited prognostic value, although preoperative measures have some prognostic value. However, acute measures of functional performance are of useful prognostic value, especially when preoperative functional performance data are unavailable. PMID:24508937

  16. Relationship between maximum isometric joint moment and functional task performance in patients with brachial plexus injury: A pilot study.

    PubMed

    Crouch, Dustin L; Santago, Anthony C; Plate, Johannes F; Li, Zhongyu; Saul, Katherine R

    2016-02-01

    We evaluated whether subjects with brachial plexus injury (BPI) adapted their movements to reduce the mechanical demand on their impaired upper extremity. In 6 subjects with unilateral BPI with C5 and C6 involvement, we measured bilateral maximum isometric shoulder and elbow strength, and computed joint kinematics and net muscle-generated joint moments during 7 unimanual functional tasks. Compared to the unimpaired extremity, maximum strength in shoulder abduction, extension, and external rotation was 60% (p=0.02), 49% (p=0.02), and 75% (p=0.02) lower, respectively, on the impaired side. Significant kinematic and kinetic differences were observed only when reaching to the back of the head. However, because of substantially reduced strength in their impaired upper extremities, subjects used a significantly higher percentage of their maximum strength during several tasks and along several directions of movement. The peak percentage of maximal strength subjects used across tasks was 32% (p=0.03) and 29% (p=0.03) more on their impaired side in shoulder extension and external rotation, respectively. Subjects had less reserve strength available for performing upper extremity tasks and, therefore, may be less adaptive to strength declines due to injury progression and normal aging. Quantitatively measuring maximal strength may help clinicians ensure that patients maintain sufficient upper extremity strength to preserve long-term functional ability.

  17. Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion.

    PubMed

    Hattori, Y; Ono, Y; Shimaoka, M; Hiruta, S; Kamijima, M; Shibata, E; Ichihara, G; Ando, S; Villaneuva, M B; Takeuchi, Y

    1996-06-01

    A laboratory study was undertaken to determine the postural and physical characteristics and subjective stress during dynamic lifting of a usual load (10 kg) compared with during isometric lifting. The authors also aimed to clarify the effects of asymmetric lifting on these parameters. The subjects were thirteen male college students. They were asked to lift a box weighing 10 kg. They performed sixteen different lifting tasks from the floor to a height of 71 cm, involving a combination of three independent factors: two lifting modes (isometric lifting and dynamic lifting), four lifting angles in relation to the sagittal plane (sagittal plane, right 45 degree, right 90 degree and left 90 degree planes) and two lifting postures (squat and stoop). For each lifting task, strengths or forces and ground reaction forces were measured. At the end of each task, the authors asked the subjects to rate their perceived exertion (RPE) during lifting at ten sites of the body. Angle factor had a significant effect on isometric strengths and dynamic peak forces. Isometric strengths during the maximum 3 s were highest in lifting in the right 45 degree plane, followed by that in the sagittal plane, while those in the right 90 degree and left 90 degree planes were the lowest. However, peak forces in dynamic lifting were the highest in the lifting in the sagittal plane, followed by that in the right 45 degree plane, while those in the right 90 degree and left 90 degree planes were the lowest. Postural factor had a significant effect on height at peak force, which is higher in squat lifting than in stoop lifting. RPEs for the left arm, the backs and the right whole body in isometric lifting were significantly higher than in dynamic lifting of 10 kg. There were remarkably high RPEs for the ipsilateral thigh to the box in right 90 degree and left 90 degree planes during both isometric and dynamic liftings. Locations of the resultant force consisting of three component forces on the force

  18. Effect of active pre-shortening on isometric and isotonic performance of single frog muscle fibres.

    PubMed Central

    Granzier, H L; Pollack, G H

    1989-01-01

    1. We studied the effects of shortening history on isometric force and isotonic velocity in single intact frog fibres. Fibres were isometrically tetanized. When force reached a plateau, shortening was imposed, after which the fibre was held isometric again. Isometric force after shortening could then be compared with controls in which no shortening had taken place. 2. Sarcomere length was measured simultaneously with two independent methods: a laser-diffraction method and a segment-length method that detects the distance between two markers attached to the surface of the fibre, about 800 microns apart. 3. The fibre was mounted between two servomotors. One was used to impose the load clamp while the other cancelled the translation that occurred during this load clamp. Thus, translation of the segment under investigation could be minimized. 4. Initial experiments were performed at the fibre level. We found that active preshortening reduced isometric force considerably, thereby confirming earlier work of others. Force reductions as large as 70% were observed. 5. Under conditions in which there were large effects of shortening at the fibre level, we measured sarcomere length changes in the central region of the fibre. These sarcomeres shortened much less than the fibre's average. In fact, when the load was high, these sarcomeres lengthened while the fibre as a whole shortened. Thus, while the fibre-length signal implied that sarcomeres might have shortened to some intermediate length, in reality some sarcomeres were much longer, others much shorter. 6. Experiments performed at the sarcomere level revealed that isometric force was unaffected by previous sarcomere shortening provided the shortening occurred against either a low load or over a short distance. However, if the work done during shortening was high, force after previous shortening was less than if sarcomeres had remained at the final length throughout contraction. The correlation between the force deficit and

  19. C*-algebras associated with reversible extensions of logistic maps

    NASA Astrophysics Data System (ADS)

    Kwaśniewski, Bartosz K.

    2012-10-01

    The construction of reversible extensions of dynamical systems presented in a previous paper by the author and A.V. Lebedev is enhanced, so that it applies to arbitrary mappings (not necessarily with open range). It is based on calculating the maximal ideal space of C*-algebras that extends endomorphisms to partial automorphisms via partial isometric representations, and involves a new set of 'parameters' (the role of parameters is played by chosen sets or ideals). As model examples, we give a thorough description of reversible extensions of logistic maps and a classification of systems associated with compression of unitaries generating homeomorphisms of the circle. Bibliography: 34 titles.

  20. Anterior Knee Pain (Chondromalacia Patellae).

    ERIC Educational Resources Information Center

    Garrick, James G.

    1989-01-01

    This article presents a pragmatic approach to the definition, diagnosis, and management of anterior knee pain. Symptoms and treatment are described. Emphasis is on active involvement of the patient in the rehabilitation exercise program. (IAH)

  1. Arthroplasty of a Charcot knee

    PubMed Central

    Babazadeh, Sina; Stoney, James D.; Lim, Keith; Choong, Peter F.M.

    2010-01-01

    The Charcot knee - or neuropathic arthropathy - presents a considerable challenge to the orthopaedic surgeon. Caused by a combination of sensory, motor and autonomic neuropathy, it was originally described as an arthritic sequelae of neurosyphilis. In today's western orthopaedics it is more often caused by diabetes. A Charcot knee is often symptomatically painful and unstable. Traditional management has usually been conservative or arthrodesis, with limited success. Arthroplasty of a Charcot joint has commonly been avoided at all costs. However, in the right patient, using the right technique, arthroplasty can significantly improve the symptoms of a Charcot joint. This article explores the evidence surrounding the role of arthroplasty in the management of a Charcot knee. Arthroplasty is compared to other forms of treatment and specific patient demographics and surgical techniques are explored in an attempt to define the role of arthroplasty in the management of a Charcot knee. PMID:21808708

  2. Bowlegs and Knock-Knees

    MedlinePlus

    ... Infections Learning Disabilities Obesity Orthopedic Prevention Sexually Transmitted ... and Knock-Knees Page Content Article Body Toddlers’ legs often have a bowed appearance. In fact, many children have bowing of the ...

  3. Reliability, Concurrent Validity, and Minimal Detectable Change for iPhone Goniometer App in Assessing Knee Range of Motion.

    PubMed

    Mehta, Saurabh P; Barker, Katherine; Bowman, Brett; Galloway, Heather; Oliashirazi, Nicole; Oliashirazi, Ali

    2016-11-28

    Much of the published works assessing the reliability of smartphone goniometer apps (SG) have poor generalizability since the reliability was assessed in healthy subjects. No research has established the values for standard error of measurement (SEM) or minimal detectable change (MDC) which have greater clinical utility to contextualize the range of motion (ROM) assessed using the SG. This research examined the test-retest reproducibility, concurrent validity, SEM, and MDC values for the iPhone goniometer app (i-Goni; June Software Inc., v.1.1, San Francisco, CA) in assessing knee ROM in patients with knee osteoarthritis or those after total knee replacement. A total of 60 participants underwent data collection which included the assessment of active knee ROM using the i-Goni and the universal goniometer (UG; EZ Read Jamar Goniometer, Patterson Medical, Warrenville, IL), knee muscle strength, and assessment of pain and lower extremity disability using quadruple numeric pain rating scale (Q-NPRS) and lower extremity functional scale (LEFS), respectively. Intraclass correlation coefficients (ICCs) were calculated to assess the reproducibility of the knee ROM assessed using the i-Goni and UG. Bland and Altman technique examined the agreement between these knee ROM. The SEM and MDC values were calculated for i-Goni assessed knee ROM to characterize the error in a single score and the index of true change, respectively. Pearson correlation coefficient examined concurrent relationships between the i-Goni and other measures. The ICC values for the knee flexion/extension ROM were superior for i-Goni (0.97/0.94) compared with the UG (0.95/0.87). The SEM values were smaller for i-Goni assessed knee flexion/extension (2.72/1.18 degrees) compared with UG assessed knee flexion/extension (3.41/1.62 degrees). Similarly, the MDC values were smaller for both these ROM for the i-Goni (6.3 and 2.72 degrees) suggesting smaller change required to infer true change in knee ROM. The i

  4. Knee Brace Would Lock And Unlock Automatically

    NASA Technical Reports Server (NTRS)

    Myers, Neill; Forbes, John; Shadoan, Mike; Baker, Kevin

    1995-01-01

    Proposed knee brace designed to aid rehabilitation of person who suffered some muscle damage in leg. Not limited to locking in straight-leg position and, instead, locks at any bend angle. Does not prevent knee from bearing weight. Instead, knee brace allows knee to bear weight and locks only when foot and lower leg bear weight. Thus, brace prevents flexion that wearer desired to prevent but could not prevent because of weakened muscles. Knee bends freely to exercise knee-related muscles. Knee brace strapped at upper end to leg above knee, and anchored at lower end by stirrup under foot. Joint mechanism (identical mechanisms used in left and right assemblies) allows knee joint to flex freely except when weight applied to heel.

  5. [Congenital knee dislocation: case report].

    PubMed

    Arvinius, C; Luque, R; Díaz-Ceacero, C; Marco, F

    2016-01-01

    Congenital knee dislocation is an infrequent condition with unknown etiology. In some cases it occurs as an isolated condition, while in others it coexists with associated conditions or syndromes. The treatment of congenital knee dislocation is driven by the severity and flexibility of the deformity. The literature includes from serial casting or the Pavlik harness to quadriceps tendon plasty or femoral osteotomies. We report herein the case of a congenital dislocation treated with serial casting with a good outcome.

  6. Comparison of maximum voluntary isometric contraction of the biceps on various posture and respiration conditions for normalization of electromyography data

    PubMed Central

    Lee, Sang-Yeol; Jo, Marg-Eun

    2016-01-01

    [Purpose] Maximum voluntary isometric contraction can increase the reliability of electromyography data by controlling respiration; however, many studies that use normalization of electromyography data fail to account for this. This study aims to check changes in maximum voluntary isometric contraction based on changes in posture and respiration conditions. [Subjects and Methods] Twenty-two healthy volunteers were included in this study. Using 22 healthy subjects, MVIC of the biceps brachii muscle was measured in three respiration conditions: (1) Maximum voluntary isometric contraction during inspiration after maximal expiration, (2) Maximum voluntary isometric contraction during expiration after maximal inspiration and (3) Maximum voluntary isometric contraction during the Valsalva maneuver. The subjects were in tested in standing and supine postures under all t