PDF(Pubmed)
Abstract：
This cross-sectional study aimed to investigate whether athletes (ATHL) and non-athletes (NON-ATHL) individuals had similar accuracy in matching intended to actual force during ballistic (BAL) and tonic (TON) isometric contractions. In this cross-sectional study, the subjects were divided into ATHL (n = 20; 22.4 ± 2.3 yrs; 73.2 ± 15.7 kg; 1.76 ± 0.08 m) and NON-ATHL (n = 20; 24.6 ± 2.4 yrs; 68.2 ± 15.0 kg; 1.73 ± 0.1 m) groups. The isometric quadriceps strength was measured with a load cell applied to a custom-built chair. For each condition, subjects performed at first three maximal voluntary isometric contractions (MVIC) as reference. Then, subjects had to match three intended force intensities expressed in percentage of the MVIC (i.e., 25%, 50%, and 75%) without any external feedback. Subjects performed three trials for each force intensity. The accuracy (AC) was calculated as the absolute difference in percentage between the intended and the actual force. A Likert scale was administered for each trial to assess the subjective matching between the intended and the actual force. Statistical analysis showed that the ATHL group was more accurate (p < 0.001) than the NON-ATHL group. In contrast, the AC (p < 0.001) was lower when the force intensities increased independently from the group. Moreover, significantly higher AC (p < 0.001) and lower aggregate Likert scores (p < 0.001) were found in BAL than TON conditions. These results suggest that (i) sports practice could enhance muscle recruitment strategies by increasing the AC in the isometric task; (ii) differences between intended and actual force appeared to be intensity-dependent with lower AC at high force intensities; (iii) different control systems act in modulating BAL and TON contractions.
摘要：
这项横断面研究旨在调查运动员（ATHL）和非运动员（NON-ATHL）个体在弹道（BAL）和补品（TON）等距收缩期间与实际力的匹配是否具有相似的准确性。在这项横断面研究中，将受试者分为ATHL（n=20；22.4±2.3年；73.2±15.7kg；1.76±0.08m）和非ATHL（n=20；24.6±2.4年；68.2±15.0kg；1.73±0.1m）组。等距股四头肌强度是通过将称重传感器应用于定制的椅子上进行测量的。对于每个条件，受试者在前三个最大自愿性等距收缩（MVIC）作为参考。然后，受试者必须匹配以MVIC百分比表示的三个预期力强度(即，25%,50%,和75%)，没有任何外部反馈。受试者对每个力强度进行三次试验。精度(AC)计算为预期力和实际力之间的绝对百分比差。每个试验都使用Likert量表来评估预期力和实际力之间的主观匹配。统计剖析显示ATHL组比NON-ATHL组更精确(p<0.001)。相比之下,当力强度独立于该组增加时，AC（p<0.001）较低。此外，与TON相比,在BAL中发现AC显著较高(p<0.001)和Likert总分较低(p<0.001).这些结果表明（i）运动练习可以通过在等距任务中增加AC来增强肌肉募集策略；（ii）预期力和实际力之间的差异似乎取决于强度，而在高力量强度下AC较低；（iii）不同的控制系统在调节BAL和TON收缩中起作用。
