Faculty of Sport Sciences, INSERM UMR1093-CAPS, Université Bourgogne, Dijon, FRANCE.
Med Sci Sports Exerc. 2023 Jun 1;55(6):1105-1113. doi: 10.1249/MSS.0000000000003132. Epub 2023 Jan 22.
The effect of cadence in eccentric (ECC) cycling on physiological and perceptual responses is, to date, poorly understood. This study aimed to evaluate the effect of cadence during ECC cycling on muscular activation (EMG), oxygen consumption (V̇O 2 ), and perceived effort (PE) for two different levels of power output.
Seventeen participants completed four sessions 1 wk apart: 1) determination of the maximal concentric peak power output (PPO) and familiarization with ECC cycling at five cadences (30, 45, 60, 75, and 90 rpm); 2) second familiarization with ECC cycling; 3) and 4) ECC cycling exercise consisting of 5 min at the five different cadences at either 40% or 60% PPO. PE was reported, and V̇O 2 and EMG of seven muscles were calculated over the exercise's last minute.
PE, V̇O 2 , and global lower limb muscles activation (EMG ALL ) showed an effect of cadence ( P < 0.001) and followed a curvilinear function. Both low and high cadences increased PE and V̇O 2 responses compared with intermediate cadences. Although muscle activation of vastus lateralis follows a U-shaped curve with cadence, it was greater at low cadence for rectus femoris and biceps femoris, greater at high cadence for tibialis anterior and gastrocnemius medialis, and was not altered for soleus. The estimated optimal cadence was greater (all P < 0.01) for V̇O 2 (64.5 ± 7.9 rpm) than PE (61.7 ± 9.4 rpm) and EMG ALL (55.9 ± 9.3 rpm), but power output had no effect on the optimal cadences.
The physiological and perceptual responses to changes in cadence during ECC cycling followed a U-shaped curve with an optimal cadence depending on the parameter considered.
目前,人们对踏频在离心(ECC)运动中的作用对生理和感知反应的影响知之甚少。本研究旨在评估在两种不同功率输出水平下,ECC 运动中踏频对肌肉激活(EMG)、耗氧量(V̇O 2 )和感知用力(PE)的影响。
17 名参与者在 1 周内完成了 4 次试验:1)确定最大向心峰功率输出(PPO)并熟悉 5 种踏频(30、45、60、75 和 90 rpm)下的 ECC 运动;2)再次熟悉 ECC 运动;3)和 4)ECC 运动包括在 40%或 60% PPO 下以 5 种不同的踏频各运动 5 分钟。在运动的最后 1 分钟,报告了 PE,计算了 V̇O 2 和 7 块肌肉的 EMG。
PE、V̇O 2 和下肢整体肌肉激活(EMG ALL )均受踏频影响(P < 0.001),呈曲线关系。与中间踏频相比,低踏频和高踏频均增加了 PE 和 V̇O 2 反应。尽管股外侧肌的肌肉激活与踏频呈 U 形曲线,但在低踏频时股直肌和股二头肌的肌肉激活更大,在高踏频时比目鱼肌和腓肠肌内侧的肌肉激活更大,而在踏频改变时比目鱼肌和腓肠肌内侧的肌肉激活没有变化。估计的最佳踏频对于 V̇O 2(64.5 ± 7.9 rpm)大于 PE(61.7 ± 9.4 rpm)和 EMG ALL(55.9 ± 9.3 rpm)(均 P < 0.01),但功率输出对最佳踏频没有影响。
ECC 运动中踏频变化引起的生理和感知反应呈 U 形曲线,最佳踏频取决于所考虑的参数。