Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, CANADA.
Med Sci Sports Exerc. 2018 Feb;50(2):375-387. doi: 10.1249/MSS.0000000000001427.
When assessing neuromuscular fatigue (NMF) from dynamic exercise using large muscle mass (e.g., cycling), most studies have delayed measurement for 1 to 3 min after task failure. This study aimed to determine the reliability of an innovative cycling ergometer permitting the start of fatigue measurement within 1 s after cycling.
Twelve subjects participated in two experimental sessions. Knee-extensor NMF was assessed by electrical nerve and transcranial magnetic stimulation with both a traditional chair setup (PRE- and POST-Chair, 2 min postexercise) and the new cycling ergometer (PRE, every 3 min during incremental exercise and POST-Bike, at task failure).
The reduction in maximal voluntary contraction force POST-Bike (63% ± 12% PRE; P < 0.001) was not different between sessions and there was excellent reliability at PRE-Bike (intraclass correlation coefficient [ICC], 0.97; coefficients of variation [CV], 3.2%) and POST-Bike. Twitch (Tw) and high-frequency paired-pulse (Db100) forces decreased to 53% ± 14% and 62% ± 9% PRE, respectively (P < 0.001). Both were reliable at PRE-Bike (Tw: ICC, 0.97; CV, 5.2%; Db100: ICC, 0.90; CV, 7.3%) and POST-Bike (Tw: ICC, 0.88; CV, 11.9; Db100: ICC, 0.62; CV, 9.0%). Voluntary activation did not change during the cycling protocol (P > 0.05). Vastus lateralis and rectus femoris M-wave and motor-evoked potential areas showed fair to excellent reliability (ICC, 0.45-0.88). The reduction in maximal voluntary contraction and Db100 was greater on the cycling ergometer than the isometric chair.
The innovative cycling ergometer is a reliable tool to assess NMF during and immediately postexercise. This will allow fatigue etiology during dynamic exercise with large muscle mass to be revisited in various populations and environmental conditions.
在使用大肌肉群（如骑自行车）进行动态运动时评估神经肌肉疲劳（NMF）时，大多数研究在运动失败后 1 至 3 分钟后才开始测量。本研究旨在确定一种创新的自行车测力计的可靠性，该测力计可在自行车骑行后 1 秒内开始疲劳测量。
12 名受试者参加了两个实验。通过电神经和经颅磁刺激评估膝关节伸肌 NMF，采用传统的椅子设置（PRE-和 POST-Chair，运动后 2 分钟）和新的自行车测力计（PRE，递增运动期间每 3 分钟一次和 POST-Bike，在任务失败时）。
POST-Bike 时最大自主收缩力的降低（63%±12% PRE；P<0.001）在两次实验中没有差异，并且在 PRE-Bike 时具有极好的可靠性（组内相关系数 [ICC]，0.97；变异系数 [CV]，3.2%）和 POST-Bike。Tw （Tw）和高频成对脉冲（Db100）的力分别降低至 53%±14%和 62%±9% PRE（P<0.001）。两者在 PRE-Bike 时均具有可靠性（Tw：ICC，0.97；CV，5.2%；Db100：ICC，0.90；CV，7.3%）和 POST-Bike（Tw：ICC，0.88；CV，11.9%；Db100：ICC，0.62%；CV，9.0%）。在自行车方案期间，自愿激活没有改变（P>0.05）。股外侧肌和股直肌 M 波和运动诱发电位面积显示出良好到极好的可靠性（ICC，0.45-0.88）。与等长椅子相比，自行车测力计上的最大自主收缩和 Db100 的降低更大。
创新的自行车测力计是一种可靠的工具，可在运动中和运动后立即评估 NMF。这将允许在各种人群和环境条件下重新研究大肌肉群动态运动时的疲劳病因。
