Measurement of Isokinetic Strength in Prepubertal Males

Abstract

Twenty-nine prepubertal males P a g e = 8.2 & 1.3 years) were evaluated for concentric isokinetic strength at the knee, shoulder, and elbow joints, [at the dominant (D) and nondominant (ND) sides]. At each joint, flexion (F) was compared with extension (E) at two speeds of 30°/sec (30) versus 90°/sec (90) over each 10% of the range of motion (ROM). Reliability was estimated between identical motions at the D versus ND side. Results for X work at the knee joint indicated slightly higher work output at the ND side (23.5 versus 25.0 joules for D versus ND), significantly higher work output for extension compared to flexion (19.0 versus 29.2 joules for F versus E) and for the slower compared to the faster speed (26.2 versus 21.9 joules for 30 versus 90). At the shoulder joint, extension resulted in significantly greater X work compared to flexion (14.2 versus 22.0 jo_ules for F versus E) and the slower speed was associated with significantly greater X work (1 9.7 versus 16.7 joules for 30 versus 90). At the elbow joint, the only significant difference observed for X work occurred for speed, with the faster speed resulting in greater X work (10.8 versus 9.5 joules for 30 versus 90). Analysis for torque scores at each of the three joints revealed that extension resulted in greater torque than flexion, 30°/sec resulted in greater torque than 90 O/sec and that peak torque scores occurred during the first 50% of ROM. Correlations to estimate reliability exceeded r = 0.70 for comparisons of torque and work scores for D versus ND. Age, height, and weight correlated r = 0.50 < r < 0.90 with peak torque during each of the motions. It was concluded that prepubertal males have similar patterns of concentric isokinetic strength measured at the knee, shoulder, and elbow joints compared to adults, because strength was greater during E versus F, for slower versus faster speeds, and during the initial phase of ROM.

Physical conditioning in children with arthritis. Assessment and guidelines for exercise prescription

“…Instrumented tests of muscle function yield reliable peak torque measurements in children [65,66], but the equipment is expensive and, with the exception of hand-heId dynamometers, is not transportable. Therapists serving children with arthritis in their homes or schools need inexpensive and easily administered tests that provide valid, reliable results.…”

Comparison of Values Generated During Testing of the Knee Using the Cybex II Plus®and Biodex Model B-2000®Isokinetic Dynamometers

“…Direct comparison of test data generated by different manufacturers' isokinetic dynamometers will help clinicians and researchers interpret promotional material, results of clinical tests, and research data. As yet, however, there have been relatively few studies that have either employed new manufacturers' machines (5, 26,[32][33][34]38,61) or directly compared isokinetic dynamometers of different manufacturers (27,62). The purpose of this study was to compare data generated by Cybex and Biodex (Shirley, NY) isokinetic dynamometers during testing of the knee joint.…”

Comparison of shoulder range of motion, strength, and endurance in amateur pitchers practicing repetitive overhead throwing

“…This ROM measurements of posterior shoulder tightness had high reliability and validity (ICC = 0.92, r = −0.61). The study also showed that patients with impingement syndrome had decreased shoulder internal and external rotator's strength compared to normal people, and that isokinetic measurement of internal and external rotator's strength in assessing shoulder muscle strength is a reliable way to measure strength of the rotator cuff muscle (r = 0.70) [20]. This is also supported by findings of Grossman et al [4] that posterior capsule tightness related to such a reduction of internal rotation caused the humeral head to shift toward the anterosuperior region that could lead to gradual injury of the rotator cuff [11].…”