Issn Print: 0195-9131
Publication Date: 2001/05/01
FORCE VELOCITY RELATIONSHIP OF MUSCLE CONTRACTION AT SLOW ECCENTRIC ISOKINETIC VELOCITIES
J Kwantes; M Rassmussen; J A. Mercer; M Hoffman; L R. Osternig
+ Author Information
Author Information: University of Nevada, Las Vegas
Excerpt
The purpose of this study was to investigate eccentric performance of muscle contraction during isokinetic knee flexion exercise. Six males and two females (median age = 24; height = 68.7 ± 2.8 in; weight = 78.3 ± 8.5 kg) performed three isokinetic repetitions of knee flexion exercise at eccentric speeds of 5, 10, 15, and 20 ± /sec. Subjects also performed a 5 second isometric contraction at angles of 35°, 45°, and 55°. For each repetition, tangential force (FT) was analyzed at three different positions: 35°, 45°, and 55°. For each position, data were averaged across three trials and analyzed using a repeated measure ANOVA followed up with planned comparisons between isometric condition and each eccentric condition. The omnibus F-ratio indicated a significant difference in FT across speeds at 35° (p < 0.05), 45° (p < 0.05) and 55° (p < 0.05) degrees of knee flexion. At each knee flexion position, planned comparisons indicated FT during the isometric condition was significantly different than FT during 5°/sec eccentric speed (p < 0.05) but not different than FT during 10, 15, and 20 °/sec (p > 0.05). It appears that at slow eccentric speeds, less force was produced compared to the isometric contractions as well as during higher eccentric speeds. It is not presently known why the force-velocity relationship of muscle contraction at slow speeds is different in vivo compared to the in vitro model.
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