Université Côte d'Azur, LAMHESS, Nice, FRANCE.
Université Côte d'Azur, CNRS, I3S, Nice, FRANCE.
Med Sci Sports Exerc. 2021 May 1;53(5):904-917. doi: 10.1249/MSS.0000000000002557.
We determined the recovery from neuromuscular fatigue in six professional (PRO) and seven moderately trained (MOD) cyclists after repeated cycling time trials of various intensities/durations.
Participants performed two 1-min (1minTT) or two 10-min (10minTT) self-paced cycling time trials with 5 min of recovery in between. Central and peripheral fatigue were quantified via preexercise to postexercise (15-s through 15-min recovery) changes in voluntary activation (VA) and potentiated twitch force. VA was measured using the interpolated twitch technique, and potentiated twitch force was evoked by single (QTsingle) and paired (10-Hz (QT10) and 100-Hz (QT100)) electrical stimulations of the femoral nerve.
Mean power output was 32%-72% higher during all the time trials and decreased less (-10% vs -13%) from the first to second time trial in PRO compared with MOD (P < 0.05). Conversely, exercise-induced reduction in QTsingle and QT10/QT100 was significantly lower in PRO after every time trial (P < 0.05). Recovery from fatigue from 15 s to 2 min for QTsingle and QT10/QT100 was slower in PRO after every time trial (P < 0.05). In both groups, the reduction in QTsingle was lower after the 10minTTs compared with 1minTTs (P < 0.05). Conversely, VA decreased more after the 10minTTs compared with 1minTTs (P < 0.05).
Our findings showed that excitation-contraction coupling was preserved after exercise in PRO compared with MOD. This likely contributed to the improved performance during repeated cycling time trials of various intensity/duration in PRO, despite a slower rate of recovery in its early phase. Finally, the time course of recovery from neuromuscular fatigue in PRO was dependent on the effects of prolonged low-frequency force depression.
我们测定了 6 名专业（PRO）和 7 名中等训练水平（MOD）自行车运动员在不同强度/时长的多次循环计时赛（cycling time trial）后，神经肌肉疲劳的恢复情况。
参与者进行了两次 1 分钟（1minTT）或两次 10 分钟（10minTT）的自我计时赛，两次之间有 5 分钟的恢复期。通过运动前后（15 秒至 15 分钟恢复期）的自愿激活（VA）和增强的抽搐力变化来量化中枢和外周疲劳。VA 使用插值抽搐技术测量，增强的抽搐力通过对股神经进行单次（QTsingle）和成对（10Hz（QT10）和 100Hz（QT100））电刺激来诱发。
在所有的计时赛中，平均功率输出均高出 32%-72%，与 MOD 相比，PRO 中的第一次和第二次计时赛之间的下降幅度较小（-10%比-13%，P<0.05）。相反，PRO 在每次计时赛后，QTsingle 和 QT10/QT100 的运动诱导降低幅度均显著降低（P<0.05）。PRO 在每次计时赛后，从 15 秒到 2 分钟，QTsingle 和 QT10/QT100 的疲劳恢复速度均较慢（P<0.05）。在两组中，与 1minTT 相比，10minTT 后 QTsingle 的降低幅度较低（P<0.05）。相反，与 1minTT 相比，10minTT 后 VA 下降幅度更大（P<0.05）。
我们的研究结果表明，与 MOD 相比，PRO 在运动后兴奋-收缩偶联仍能得到保留。这可能有助于 PRO 在各种强度/时长的多次循环计时赛中表现更好，尽管在早期恢复阶段的恢复速度较慢。最后，PRO 神经肌肉疲劳恢复的时间过程取决于长时间低频力抑制的影响。
