O'bryan Steven J, Billaut François, Taylor Janet L, Rouffet David M
a Institute of Sport, Exercise and Active Living (ISEAL) , Victoria University , Melbourne , Australia.
b Département de kinésiologie , Université Laval , Québec , Canada.
J Sports Sci. 2018 May;36(9):1030-1037. doi: 10.1080/02640414.2017.1349922. Epub 2017 Jul 18.
We investigated the association between changes in vastii electromyography (EMG) and knee extensor fatigue during high-intensity cycling, and the subsequent effect on lower-limb power and intermuscular coordination during all-out cycling. On two separate days, participants completed 30-s all-out cycling or 10-min of high-intensity cycling followed by 30-s all-out cycling. EMG for gluteus maximus (GMAX), rectus femoris (RF), vastii (VAS), hamstrings (HAM) and gastrocnemius (GAS); co-activation for GMAX/RF, VAS/HAM and VAS/GAS; isometric maximal voluntary force (IMVF) and resting twitch (RT) of the knee extensors were measured. VAS EMG increases during high-intensity cycling (6% to 14%, P < 0.05) were negatively correlated (r = -0.791, P < 0.05) with knee extensor IMVF decreases (-2% to-36%, P < 0.05) following the exercise. Knee extensor IMVF decreases were positively correlated (r = 0.757, P < 0.05) with all-out cycling power reductions (0% to -27%, P < 0.05). VAS/GAS co-activation did not change (P > 0.05) during all-out cycling while VAS and GAS EMG decreased. Larger increase in VAS EMG during high-intensity cycling was associated with greater knee extensor fatigue and larger power reduction during all-out cycling. High VAS/GAS co-activation potentially limited power reduction induced by knee extensor fatigue during all-out cycling.
我们研究了高强度骑行过程中股四头肌肌电图（EMG）变化与膝关节伸肌疲劳之间的关联，以及随后对全力骑行过程中下肢力量和肌肉间协调性的影响。在两个不同的日子里，参与者完成了30秒的全力骑行或10分钟的高强度骑行，随后进行30秒的全力骑行。测量了臀大肌（GMAX）、股直肌（RF）、股四头肌（VAS）、腘绳肌（HAM）和腓肠肌（GAS）的肌电图；GMAX/RF、VAS/HAM和VAS/GAS的共同激活；膝关节伸肌的等长最大自主力量（IMVF）和静息抽搐（RT）。高强度骑行过程中VAS肌电图增加（6%至14%，P<0.05）与运动后膝关节伸肌IMVF降低（-2%至-36%，P<0.05）呈负相关（r=-0.791，P<0.05）。膝关节伸肌IMVF降低与全力骑行功率降低（0%至-27%，P<0.05）呈正相关（r=0.757，P<0.05）。在全力骑行过程中，VAS/GAS共同激活没有变化（P>0.05），而VAS和GAS肌电图降低。高强度骑行过程中VAS肌电图更大的增加与更大的膝关节伸肌疲劳和全力骑行过程中更大的功率降低相关。高VAS/GAS共同激活可能限制了全力骑行过程中膝关节伸肌疲劳引起的功率降低。
