科研之友
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摘要
Ten prepubertal girls and 15 young women were tested for maximal torque, peak rate of torque development, electro-mechanical delay (EMD), and time to peak rate of torque development during isometric elbow flexion. Absolute peak torque (17.0 /- 7.7 vs. 40.5 /- 8.3 Nm) and peak rate of torque development (105.9 /- 58.6 vs. 297.2 /- 113.0 Nm.s(-1)) were lower in the girls (p <.05). Normalized to muscle cross sectional area, torque was similar (8.27 /- 2.74 vs. 8.44 /- 1.65 Nm.cm(-2)), as was peak rate of torque development, normalized to peak torque (6.21 /- 1.94 vs. 7.30 /- 2.26 Nm.s(-1)/Nm). Both, time to peak rate of torque development (123.8 /- 36.0 vs. 110.5 /- 52.6 ms) and EMD (73.2 /- 28.6 vs. 51.9 /- 25.6 ms), were longer in the girls, although EMD's difference only approached statistical significance (p = .06). Age-related isometric strength differences in females appear to be mainly muscle-size dependent. However, the time to peak torque and EMD findings suggest differential motor-unit activation which may functionally manifest itself in fast dynamic contractions.
- 出版日期2009-8
