De Ste Croix Mark B A, Deighan Martine A, Ratel Sebastien, Armstrong Neil
Department of Sport and Exercise, University of Gloucestershire, Gloucester GL2 9HW, UK.
Appl Physiol Nutr Metab. 2009 Aug;34(4):725-31. doi: 10.1139/H09-064.
The purpose of this study was to examine the age- and sex-associated differences of repeated isokinetic knee extension and flexion. Fifty one participants, 30 young children (16 boys and 14 girls; aged 11 and 12 years) and 21 adults (9 males and 12 females; aged 18-35 years), agreed to participate in the study. Isokinetic concentric peak knee extension (PET) and flexion (PFT) torque were measured using a calibrated Biodex System 3. Participants performed 4 concentric extension-flexion cycles with maximum effort; after a 2 min rest, 50 continuous concentric cycles were performed at 1.56 rad.s-1. Total work of the extensors (WKEX) and flexors (WKFL) for the complete 50 repetitions was recorded. Average peak torque and average work for the first and last 3 repetitions were calculated to represent the percentage decline in torque and work. There were no significant differences between groups in the peak torque generated during the pretrial and endurance task, suggesting that participants gave a maximal effort at the start of the endurance task. There was a significant interaction effect in the total work done for both extensors and flexors, with adult males producing the greatest amount of work (6622 and 3444 J, respectively). When total work was divided by body mass, there were no significant sex effects, only main effects for group. The percentage decline for PET (40% vs. 60%), PFT (50% vs. 65%), WKET (43% vs. 61%), and WKFL (60% vs. 69%) demonstrated significant main effects for group, with greater fatigue in adults. We found no significant sex effect for fatigue. This study concludes that females do not resist fatigue from repeated isokinetic muscle actions to a greater extent than males, and that the greater fatigue in adults than in children is probably a product of greater initial torque production and work performed.
本研究的目的是探讨重复等速膝关节伸展和屈曲与年龄及性别的相关差异。51名参与者，30名儿童（16名男孩和14名女孩；年龄11至12岁）和21名成年人（9名男性和12名女性；年龄18 - 35岁）同意参与本研究。使用校准后的Biodex System 3测量等速向心膝关节伸展（PET）和屈曲（PFT）的峰值扭矩。参与者以最大努力进行4次向心伸展 - 屈曲循环；休息2分钟后，以1.56 rad.s-1进行50次连续向心循环。记录完整50次重复中伸肌（WKEX）和屈肌（WKFL）的总功。计算前3次和后3次重复的平均峰值扭矩和平均功，以表示扭矩和功的下降百分比。在预试验和耐力任务期间产生的峰值扭矩在组间无显著差异，表明参与者在耐力任务开始时已竭尽全力。伸肌和屈肌所做的总功存在显著的交互作用，成年男性产生的功最大（分别为6622焦耳和3444焦耳）。当总功除以体重时，没有显著的性别效应，只有组的主效应。PET（40%对60%）、PFT（50%对65%）、WKET（43%对61%）和WKFL（60%对69%）的下降百分比显示出组的显著主效应，成年人疲劳程度更高。我们发现疲劳没有显著的性别效应。本研究得出结论，女性在重复等速肌肉动作中抵抗疲劳的程度并不比男性更大，并且成年人比儿童更大的疲劳可能是更大的初始扭矩产生和所做功的结果。
