Torque/Velocity Properties of Human Knee Muscles: Peak and Angle-Specific Estimates (original) (raw)
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A Trend Analysis of the In Vivo Quadriceps Femoris Angle-Specific Torque-Velocity Relationship
Journal of Orthopaedic & Sports Physical Therapy, 1997
To adequately assess isokinetic human muscle performance, it is important for clinicians to understand how the muscle functions across a range of velocities. Thus, the purpose of this study was to re-examine the in vivo quadriceps torque-velocity relationship using trend analysis. Twelve uninjured university-age females performed three concentric and eccentric contractions at velocities of 0, 25, 50, 75, 100, 125, 150, 175, and 200°/sec on the Kin-Corn isokinetic dynamometer. A trend analysis was performed on the angle-specific torques at 30, 60, and 75° of knee flexion. The results indicated that the concentric and eccentric relationships at 30° and the concentric relationship at 60° were represented by a third-order polynomial, and a linear relationship was found for concentric contractions at 75°. There were no significant trends for the eccentric relationship at 60 and 75°, suggesting that they were best described by the grand mean. These results suggest that muscular torque production varies across velocities and contraction modes and that this relationship varies depending on the joint angle of torque measurement.
PloS one, 2018
The current study aimed to examine the reliability of the conventional and functional ratios derived from peak torques (PTs) and those obtained from the combination of knee flexors torque at the angle of knee extensors PT. Twenty-six male athletes (mean of 24.0±0.7 years) from different sports completed a test-to-test variation in isokinetic strength (Biodex, System 3) within a period of one week. Anthropometry and body composition assessed by Dual Energy X-ray Absorptiometry were also measured. The proposed isokinetic strength ratio measurements appeared to be highly reliable: conventional ratio at PT angle (intra-class correlation, ICC = 0.98; 95% confidence interval; 95%CI: 0.95 to 0.99); functional extension ratio at PT angle (ICC = 0.98; 95%CI: 0.96 to 0.99); and, functional flexion ratio at PT angle (ICC = 0.95; 95%CI: 0.89 to 0.98). Technical error of measurement (TEM) and associated percentage of the coefficient of variation (%CV) were as follows: conventional ratio at PT an...
Relative torque contribution of vastus medialis muscle at different knee angles
Acta Physiologica, 2008
Aim: We investigated the relative contribution of the vastus medialis (VM) muscle to total isometric knee extension torque at 10°, 30°, 60°and 90°knee flexion. In the past a more prominent role of the VM muscle at more extended knee angles has been put forward. However, different components of the quadriceps muscle converge via a common distal tendon. We therefore hypothesized that the relative contribution of the VM to total knee extension torque would be similar across angles. Methods: At each knee angle the EMG isometric torque relations [20%, 25%, 30%, 35% maximal voluntary contraction (MVC)] of the rectus femoris (RF), vastus lateralis (VL) and VM muscle were established in 10 healthy male subjects; rectified surface EMG was normalized to M-wave area. Subsequently, the VM was functionally eliminated by selective electrical surface stimulation with occluded blood flow. Results: There was no evidence for preferential activation of VM at any of the knee angles. Following VM elimination, total knee extension torque during maximal femoral nerve stimulation (three pulses at 300Hz) at 10°, 30°, 60°and 90°, respectively, decreased (P < 0.05) to (mean AE SD): 75.7 AE 12.2, 75.1 AE 9.3, 78.2 AE 7.2 and 76.0 AE 5.8% (P > 0.05 among knee angles). In addition, during voluntary contractions at 20% MVC the increases in torque output of RF and VL compensating for the loss of VM function were calculated from the increases in EMG and found to be similar (P > 0.05) at 10°, 30°, 60°and 90°values (%MVC), respectively, were: 9.1 AE 6.8, 7.5 AE 2.9, 5.9 AE 3.7 and 6.9 AE 3.4. Conclusion: The present findings support our hypothesis that the VM contributes similarly to total knee extension torque at different knee angles.
Journal of Applied Physiology, 2005
The single joint torque exertion task has been widely used as a very efficient method to control muscle activity. In the task, only the relevant joint torque is specified, and generally the other joint torques are not taken into consideration. However, our previous study has shown that the muscle activity level is indefinite even for mono-articular muscles unless the neighboring joint torque is specified. Therefore, the neglect of the neighboring joint could make the activity level of the relevant joint muscles ambiguous. Here we investigated how much hip joint torque was generated while subjects tried to exert knee joint torque and how it affected the activity of the knee joint muscles. Twelve healthy subjects were requested to exert various levels of isometric knee joint torque (extension and flexion). The knee and hip joint torques were obtained using a custommade force measurement device. Since no information about hip joint torque was provided to the subjects, the hip joint torque measured here was a secondary one associated with the knee joint torque exertion. The subjects could be divided into two groups according to the profile of the hip joint torque: for example, knee extension torque accompanied either large hip flexion torque or almost no hip joint torque. Such a difference in the hip joint torque was not negligible, because the knee joint muscle activity level with respect to the knee joint torque level, as quantified by surface electromyography (EMG), changed significantly when the subjects were requested to use the other strategy. This change occurred in a very systematic manner: in the case of the knee extension, as the hip flexion torque was larger, the activity of mono-and bi-articular knee extensors decreased and increased, respectively. These results indicate that the conventional single knee joint torque exertion has the drawback that the inter-subject and/or inter-trial variability is inevitable in the relative contribution among mono-and bi-articular muscles due to the uncertainty of the hip joint torque.
2014
PURPOSE: To assess and compare the force-velocity-power relationship (F-V-P) using isotonic and isokinetic knee extensions in 11 younger (19-30y) and 11 older (69-81y) men. METHODS: The construction of the F-V-P curves were attained with each participant performing maximal, explosive knee extensions at 8 different loads (isotonic) and 8 different velocities (isokinetic) on a Cybex HUMAC NORM dynamometer. Maximal voluntary contraction (MVC or Po), maximal shortening velocity (Vmax), maximum power, optimal torque (Popt) and velocity (Vopt) were assessed and compared. RESULTS: The older men were 43% weaker, 18% slower and ~54% less powerful than the younger men for both isotonic and isokinetic contractions. For the older men, Popt was 35% and 38% lower in the isotonic and isokinetic F-V-P relationships, respectively. The Vopt of the older men were 36% and 25% slower, respectively in the isotonic and isokinetic power curves. Interestingly, the Vopt achieved during isokinetic testing was 16% and 36% higher for both younger (400 vs 346°/s) and older (300 vs 221°/s) men, respectively, compared to the isotonic Vopt. CONCLUSION: For the isotonic modality, the weaker and slower knee extensors of the older men contributed equally to lower power whereas for the isokinetic modality, age-related muscle weakness contributed more than velocity to the reduction in power. The muscle behaves differently between modalities, which may explain parts of the results. The isotonic modality better modelled the F-V relationship, with fewer inherent limitations compared to the isokinetic modality.
Test-retest reliability of reciprocal isokinetic knee extension and flexion peak torque measurements
Journal of athletic training, 1992
Our purpose in conducting this study was to estimate the reliability of reciprocal concentric knee extension and flexion peak torque obtained in uninjured male athletes using the Biodex isokinetic dynamometer. Twenty-six male intercollegiate athletes (age=19.5+/-4.1 yr; ht=70.3+/-14.9 in; wt=212.9+/-48.5 lb) participated in this study. We used the Biodex to measure peak torque occurring during right knee extension and flexion over 3 consecutive days. Means and standard deviations were calculated for both extension and flexion on each of the 3 days. We observed a significant main effect for days for both extension and flexion. Mean peak torque for the first day was significantly higher (Turkey, p<.05) than the means for the other 2 days, which were not significantly different from each other (Turkey, p>0.05). Intraclass correlation coefficients (ICCs) were estimated for each of the six trials on each of the 3 days. Intraclass correlation coefficients (ICCs) ranged from .88 on t...
Dependency of knee extension torque on different types of stabilisation
International Journal of Human Factors Modelling and Simulation, 2012
Can isolated single-joint torque measurements be used for every practical use case concerning strength prediction or does the possibility of support and stabilisation influence the results? Some studies show that, for example, using or not using handgrips influences maximum knee extension joint torques. This suggests that a muscle can transmit a higher force than it can generate. This would have incisive consequences on digital human modelling. In this case, a strength prediction model would need the information about possible contact points that could increase the resulting joint torque by recruiting further muscle groups. In this study, three stabilisation methods (waist belt, upper body restraint, handgrips and waist belt) were used for maximum isometric knee joint torque measurements using 21 young, male subjects. The results show that in contrast to some earlier studies no significant differences could be obtained. Based on the results recommendations for appropriate stabilisation are given.
Isokinetic quadriceps peak torque, average power and total work at different angular knee velocities
Isokinetic dynamometry offers distinct advantages, both clinically and for research, in the evaluation and treatment of muscle performance .previous research has reported a high level of correlation between peak torque and work and between peak torque and power in the muscles surrounding normal and selected pathological knees. No research to date has examined whether such similarities exist in clients with no pathology to the knee in elderly with certain testing conditions. The purpose of this study was to investigate the relationship between the isokinetic parameters of peak torque PT, work, and power for the extensor muscle groups of elderly female. The main aim was to ascertain how the angular velocity can affect the relation between peak torque, average power and total work. Subjects, materials and methods: Isokinetic data were collected from 60 females; mean age 68.6 years on a Biodex isokinetic testing and training dynamometer at the speeds of 60, and°180, /sec. suggest that peak torque is representative of work and power and may be the only necessary parameter for isokinetic muscle performance testing of the extensor muscles of the knee in elderly.
Biology
This study investigated the effects of knee joint angle on muscle activation, exerted torque, and whether the knee angle affects the muscle activation–torque ratio. Nine healthy adult male participants participated in the study. They performed maximal voluntary isometric contraction (MVIC) at six (80°, 90°, 100°, 110°, 120°, and 130°) different knee joint angles (i.e., angles between the thigh and shin bones). Their maximal torque was assessed utilizing an isokinetic chair, while their muscle activation (root mean square [RMS]) was assessed using an eight-channel single differential surface EMG sensor. For the purposes of the torque–knee angle relationship and muscle activation–knee angle relationship, the torque and RMS were normalized relative to the maximal value obtained by each participant. To evaluate the muscle activation–torque ratio in function of knee angle, RMS was normalized relative to the corresponding torque obtained at each knee angle. Repeated measure analysis of va...