Measurement of Isokinetic Strength in Prepubertal Males* (original) (raw)
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ANALYSIS OF ISOKINETIC KNEE EXTENSION / FLEXION IN MALE ELITE ADOLESCENT WRESTLERS
Wrestling requires strength of the upper and lower body musculature which is critical for the athletic performance. Evaluation of the adolescent's skeletal muscle is important to understand body movement, especially including those involved in sports. Strength, power and endurance capacity are defined as parameters of skeletal muscle biomechanical properties. The isokinetic dynamometer is an important toll for making this type of evaluation. However, load range phase of range of motion has to be considered to interpret the data correctly. With this in mind we aimed to investigate the lover body musculature contractile characteristics of adolescent wrestlers together with detailed analyses of load range phase of motion. Thirteen boys aged 12 -14 years participated to this study. Concentric load range torque, work and power of knee extension and flexion were measured by a Cybex Norm dynamometer at angular velocities from 450°/sec to 30°/sec with 30°/sec decrements for each set. None of the wrestlers were able to attain load range for angular velocities above 390°/sec and 420°/sec for extension and flexion respectively. Detailed analyses of the load range resulted in statistically significant differences in the normalized load range peak torque for extension at 270°/sec (1.44 ± 0.28 Nm·kg -1 and 1.14 ± 0.28 Nm·kg -1 for total and load range peak torque respectively, p < 0.05), and for flexion at 300 o /sec (1.26 ± 0.28 Nm·kg -1 and 1.03 ± 0.23 Nm·kg -1 for total and load range peak torque respectively, p < 0.05), compared to total peak torque data. Similarly, the significant difference was found for the work values at 90°/sec (1.91 ± 0.23 Nm·kg -1 and 1.59 ± 0.24 Nm·kg -1 for total and load range work respectively for extension and 1.73 ± 0.21 Nm·kg -1 and 1.49 ± 0.19 Nm·kg -1 for total and load range work respectively for flexion, p < 0.05), and was evident at higher angular velocities (p < 0.001) for both extension and flexion. At extension, load range power values were significantly smaller than total power for all angular velocities except 150°/sec (p < 0.05 for 120 and 180°/sec, p < 0.001 for others). Finally, load range flexion power was found to be higher than total power with statistically significance (p < 0.05 for 60, 120, 150, 180, 210, 270 and 300°/sec, p < 0.001 for 240 °/sec). Extra caution is required for correct interpretation of load range data in terms of considering the load range during limb movement. Evaluation of muscle performance of these adolescent wrestlers at regular intervals may give us an opportunity to obtain a healthy maturation profile of these adolescent wrestlers.
Isokinetic strength aspects in human joints and muscles
Applied Ergonomics, 1991
The isokinetic concept of exercise has become an increasingly popular means to assess musculoskeletal function. The isokinetic apparatus enables the control of angular velocity of the moving limb (which is held constant during the range of movement) whilst giving an accommodated resistance. The resistance produced by the device is accommodated to the net external moment exerted by the subject. Some of the advantages of isokinetic assessment are discussed. However, a number of restrictions and limitations should be considered when interpreting these strength measurements. . 1984, J ApplPhysiol, 57,435-443. Muscle architecture and force-velocity curve relationships in humans.
2019
Muscle training plays an important role intreatment of shoulder joint disorders. Strength of one upper extremity (UE) can be used as a comparison for the other one. Objective: The purpose of this study was to determine the difference in isokinetic peak torque of shoulder joint flexors and extensors in the dominant versus non-dominant UE. Relationship between dominant and nondominant shoulder joint flexor and extensor muscles was also investigated. Methodology:Shoulder isokinetic measurements were obtained from fifty children (30 boys and 20 girls) with age range 8-12 years at two angular velocities (60◦ and 180◦/sec) during flexion and extension movements.Results: There was significant difference in peak torque of shoulder joint flexors at both speeds and in shoulder joint extensors at velocity 180°/sec only in the dominant compared to the non-dominant UE.In addition, there was significant positive correlation between peak torque of shoulder joint flexors and extensors in both UE.Co...
International Journal of Environmental Research and Public Health, 2020
Background: Isokinetic testing has been routinely used to assess the capacities of individual muscle groups. In this study we aimed to evaluate the sensitivity of the force-point (F-v) relationship assessed through the two-point method to discriminate between antagonist muscle groups and males with different physical activity levels. Methods: The concentric force output of the knee, hip, elbow, and shoulder flexors and extensors of 27 active and 13 non-active men was recorded at 60 and 180°/s to determine the F-v relationship parameters (maximum force [F0], maximum velocity [v0], and maximum power [Pmax]). Results: F0 and Pmax were higher for knee extensors (effect size [ES] = 1.97 and 0.57, respectively), hip extensors (ES = 2.52 and 0.77, respectively), and shoulder flexors (ES = 1.67 and 0.83, respectively) compared to their antagonist muscles, while v0 was higher for knee flexors compared to knee extensors (ES = 0.59). Active males revealed higher F0 for knee extensors (ES = 0.7...
Biomedical Engineering-applications Basis Communications, 2001
Bkmwd Eng App! Basis Cranm, 2(X)1 (April); 13: 79-92. (torque, Nm) was the only defined dependent variable. The majority of existing joint strength prediction models and normative databases are static (isometric) in nature. The few available dynamic models are reported in the form of torque as a function of joint angle. Since joint strength is a function of both the joint angular position and angular velocity, descriptive models should take this interaction into consideration. The dynamic joint strengths of the subjects were studied using the KINCOM125E Plus. A second-order multiple regression analysis was used to model the dynamic 3-D strength surface response of each joint in each direction of exertion. Analysis of variance (ANOVA) with repeated measures design was used to test for the effects of gender, angular position, angular velocity, and direction on the dynamic strength of each joint, joint strength was significantly influenced by dynamic parameters such as the angular velocity. The interaction between angular position and velocity was highly significant. 3-D strength surface representation may be used as a "performance capacity envelope" to comprehensively characterize an individual's dynamic joint strength performance.
Physical therapy in sport : official journal of the Association of Chartered Physiotherapists in Sports Medicine, 2012
To assess the reproducibility of isokinetic eccentric and concentric knee extension and flexion strength indices obtained at two different angular velocities. Cohort study. University human performance laboratory. 45 healthy physically active young adults (25 males). A non reciprocal protocol of concentric and eccentric contractions of the knee extensors and flexors was performed at 30 and 120°/s. Strength indices evaluated included peak moment; dynamic control ratios; and the difference between eccentric and concentric ratio at the two angular velocities. No evidence for inter-test bias in any of the strength indices was noted. Measurement precision for peak moment, as quantified using ratio limits of agreement, suggest that scores may be expected to vary up to 15% for the knee extensors in both eccentric and concentric contraction modes. An error of up to 19% was calculated for the peak moment scores of the knee flexors. Intraclass correlation coefficients revealed fairly robust p...
Applied Physiology, Nutrition, and Metabolism, 2009
Muscle strength and activation were compared in boys and men during maximal voluntary elbow flexion and extension contractions. Peak torque, peak rate of torque development (dτ/dτmax), rate of muscle activation, and electromechanical delay (EMD) were measured in 15 boys (aged 9.7 ± 1.6 years) and 16 men (aged 22.1 ± 2.8 years). During flexion, peak torque was significantly lower in boys than in men (19.5 ± 5.8 vs. 68.5 ± 11.0 Nm, respectively; p < 0.05), even when controlling for upper-arm cross-sectional area (CSA), and peak electromyography activity. Boys also exhibited a lower normalized dτ/dτmax (7.2 ± 1.7 vs. 9.5 ± 1.6 (Nm·s–1)·(Nm–1), respectively; p < 0.05) and a significantly longer EMD (75.5 ± 28.4 vs. 47.6 ± 17.5 ms, respectively). The pattern was similar for extension, except that group differences in peak torque were no longer significant when normalized for CSA. These results suggest that children may be less able to recruit or fully utilize their higher-threshold...
Assessing variability in isokinetic strength through a range of motion
International Journal of Industrial Ergonomics, 1992
Developing methods for measuring and matching physical abdities of workers and physical requirements of job tasks can help prevent low back injuries and improve return-to-work rates of back-injured workers. The present study concerns the measurement and graphic depiction of Isokinetic strength (m terms of force generated) in the saglttal plane. Lifting force was measured throughout the same range of motion at four horizontal distances from the body, and at two different lifting speeds. The results show that, while absolute values of force vary, patterns of force are consistent among individuals, and are independent of gender and lift speed. Subjects were able to generate more hftlng force in lower regions (floor to waist height) that are close to the body (30% arm length), and the least force m htgh regions (shoulder height to overhead) that are farthest from the body (90% arm length). This informaUon, especially when presented pictorially, can be readily understood and applied m workplace design and in accommodations to reduce incidence of injury
Journal of Sports Sciences, 2019
This study aimed to (1) evaluate the shape of the force-velocity (F-V) relationship obtained from different muscles, (2) explore the concurrent validity of the two-point method with respect to the multiple-point method, (3) evaluate whether the F-V relationship can discriminate between muscle groups and genders, and (4) explore the generalisability of the same F-V relationship parameters (maximal force [F 0 ], maximal velocity [V 0 ]), and maximal power [P 0 ]) between different tasks. The F-V relationship of 22 physically active participants (12 women) were tested during knee extension, knee flexion, elbow extension and elbow flexion through the multiple-(eight velocities: 30-60-90-120-150-180-210-240º/s) and two-point (two velocities: 60-180º/s) methods. The findings revealed (1) highly linear F-V relationships (r ≥ 0.893), (2) high concurrent validity of the two-point method for F 0 , but lower for V 0 and P 0 , (3) the outcomes of both methods were sensitive to the muscle groups (higher for knee muscles) and gender (higher for men), and (4) the magnitude of the same F-V parameters were poorly correlated between different tasks (median r < 0.1). These results support the two-point method as a valid and sensitive procedure for determining the maximal capacities of the muscles to produce F, but not V, during isokinetic tests.