Isokinetic Peak Torque Of Knee Extensors Research Articles

Age-related effects on absolute and relative isokinetic knee extensor strength in community-dwelling older men and women at a French geriatric day hospital.

Isokinetic knee extensor strength is poorly evaluated in geriatric day hospitals (GDHs), despite its potential functional significance compared to grip strength. This study aimed to investigate age-related effects on absolute and relative isokinetic knee extensor peak torque (KEPT) data in community-dwelling older GDH patients. A total of 472 French GDH patients (179 men and 293 women, aged 75-94 years) participated in this study. Absolute and relative KEPT were measured at six distinct angular velocities between 0.52 and 3.14 rad/s. In addition, comfortable gait speed and grip strength were assessed. Participants were stratified by sex and age using 5-year intervals. One-way ANOVAs were used to examine age-related effects on KEPT values. Multiple linear regression models were employed to investigate the associations between gait speed and both mean KEPT values and grip strength, with separate models conducted on absolute and relative values. The recruited GDH patients presented lower absolute and relative KEPT values in comparison with established reference values for healthy community-dwelling older individuals, with men being consistently stronger than women. Notably, there was a significant decline in both absolute and relative KEPT values beyond the age of 85 for both sexes. Importantly, the multiple linear regression analyses conducted revealed a significant positive relationship between gait speed and mean KEPT values, surpassing the association with grip strength. These findings underscore the clinical importance of assessing isokinetic knee extensor strength in community-dwelling older GDH patients, particularly for tailoring personalized physical activity interventions.

Lack of association of the ACE genotype with the muscle strength response to resistance training

Introduction: Previous studies have attempted to link the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene with the variability in muscle strength responses to resistance training (RT); however, the literature is inconclusive. The purpose of the present study was to investigate the association between the ACE I/D genotype and muscle strength response to a RT program in young men. Methods: 124 men (22±2.6 years; 174.8±6.5cm; 71.5±13.8 kg) without resistance training experience were tested before and after 11 weeks of five whole-body RT exercises (bench press, seated row, knee extension, knee flexion and sit ups). The bench press 1RM test was used to assess upper-body muscle strength and the isokinetic knee extensor peak torque (PT) was used as a measure of lower-body strength. Results: At baseline, there were no differences among ACE genotype for 1RM load (54±11.7 kg for II, 58.5±8.9 kg for ID and 52.3±12.2 kg for DD) or knee extensor peak torque (PT) (220.1±36.8 N·m for II, 209.4 ±44.4 N·m for ID and 199.7±32.4 N·m for DD). Moreover, ACE genotype was not associated with lower-body (7.1±10.5%, 15.7±10.4% and 14.1±22.7% for II, ID and DD, respectively) or upper-body strength gains (16.2±8.9%, 14.5±11.3% and 21.9±17.1% for II, ID and DD, respectively) in response to RT. Conclusion: The ACE I/D genotype was not associated with the muscle strength responses to RT.

Treatment of anterior cruciate ligament deficiency

~~~~~~ - ~~~~ The thesis deals with the treatment of anterior cruciate ligament deficiency with special emphasis on soccer injuries. In 2 epidemiological studies the incidence of injury among 105 elite soccer players was analysed in relation to exposure risks. Further, the natural course of 132 initially non-surgically treated anterior cruciate ligament ruptures was studied prospectively in a consecutive population. In 2 studies, subjective and objective knee function were analysed in the 41 percent of the total population that still had not been reconstructed during a period of 5 years. Surgical treatment was addressed in 2 studies. The long-term effects on knee function of anterior cruciate ligament reconstruction with a synthetic Dacron high-strength ligament (Stryker) were studied prospectively in 42 patients. Autogenous patellar tendon and synthetic Leeds-Keio grafts in the reconstruction of anterior cruciate ligament ruptures were compared prospectively in 60 randomized patients. The incidence of injury in elite female soccer players per unit exposure time was more than twice as high as in male elite players. Most injuries were minor or moderate. Of the major injuries, anterior cruciate ligament tears were the most serious. Players sustaining this injury were sidelined from the elite level for a long time, sometimes permanently. Few patients were pleased with their knee function after sustaining an anterior cruciate ligament rupture if treated non-surgically, despite a thorough rehabilitation program. Pain and functional instability were the most common symptoms. The ACL injured leg also showed an impairment in isokinetic muscle performance. The one-leg-hop performance test was shown to be a valid functional measure of isokinetic knee extensor peak torque. The eccentric knee extensor endurance test seems to reflect the patient's subjective knee function. Among the different surgical methods selected for study, the autogenous patellar tendon graft is preferable. Because of increasing instability during the course of the study, the synthetic Dacron high-strength ligament (Stryker) and the synthetic Leeds-Keio graft cannot be recommended for ACL reconstruction.

Lifting Ability and Leg Strength

The purpose of this study was to determine the relationship between peak torques of lower extremity muscle groups and lifting ability with a floor-to-knuckle leg lift in a healthy person. Twenty-four healthy, young subjects between the ages of 20 and 40 participated in the study. Each subject was tested for 1) isokinetic peak torque of the knee extensors and flexors and hip extensors and flexors on a Cybex II dynamometer, 2) isometric lifting ability using a strain gauge dynamometer, and 3) maximum lifting ability using a box and free weights. The subjects used a squat technique and maintained a neutral spine position with a lordotic curve during the lifts. No significant correlations were found with the data analysis for the entire group. For 15 male subjects, the regression equations revealed a statistically significant correlation between isokinetic knee extensor peak torque (180 degrees /sec) and isokinetic hip extensor peak torque (30 degrees /sec) with both maximum lifting ability and isometric lifting ability. The regression equations were MAXIMUM LIFT = 46.1 + 0.92Q + 0.10H (F = 4.07, p < 0.05) and ISOMETRIC LIFT = 16.6 + 23Q + 1.05H (F = 6.32, p < 0.025) (Q: isokinetic knee extensor peak torque at 180 degrees /sec; H: isokinetic hip extensor peak torque at 30 degrees /sec). No statistically significant correlations were found for the nine females. These results indicate that in a healthy, young population, isokinetic knee extensor and hip extensor peak torque may be predictors of floor-to-knuckle leg lifting ability in males, but not in females. J Orthop Sports Phys Ther 1991;14(1):24-30.