Moore Isabel S, Jones Andrew M, Dixon Sharon J
Sports Injury Research Group, Cardiff School of Sport, Cardiff Metropolitan University, UK; Bioenergetics and Human Performance Research Group, Sport and Health Sciences, University of Exeter, UK.
Bioenergetics and Human Performance Research Group, Sport and Health Sciences, University of Exeter, UK.
J Sci Med Sport. 2014 Nov;17(6):671-6. doi: 10.1016/j.jsams.2013.09.014. Epub 2013 Oct 18.
Muscular coactivation can help stabilise a joint, but contrasting results in previous gait studies highlight that it is not clear whether this is metabolically beneficial. The aim was to assess the relationship between the metabolic cost of running and muscular coactivation across different running speeds, in addition to assessing the reliability and precision of lower limb muscular coactivation.
Eleven female recreational runners visited the laboratory on two separate occasions. On both occasions subjects ran at three speeds (9.1, 11 and 12 km h(-1)) for six minutes each.
Oxygen consumption and electromyographic data were simultaneously recorded during the final two minutes of each speed. Temporal coactivations of lower limb muscles during the stance phase were calculated. Five muscles were assessed: rectus femoris, vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius lateralis.
Nonparametric correlations revealed at least one significant, positive association between lower limb muscular coactivation and the metabolic cost of running for each speed. The length of tibialis anterior activation and muscular coactivation of the biceps femoris-tibialis anterior and gastrocnemius lateralis-tibialis anterior decreased with speed.
These results show that longer coactivations of the proximal (rectus femoris-biceps femoris and vastus lateralis-biceps femoris) and leg extensor (rectus femoris-gastrocnemius lateralis) muscles were related to a greater metabolic cost of running, which could be detrimental to performance. The decrease in coactivation in the flexor and distal muscles at faster speeds occurs due to the shorter duration of tibialis anterior activation as speed increases, yet stability may be maintained.
肌肉协同激活有助于稳定关节，但以往步态研究结果相互矛盾，这凸显出目前尚不清楚这种激活在代谢方面是否有益。本研究旨在评估不同跑步速度下跑步代谢成本与肌肉协同激活之间的关系，同时评估下肢肌肉协同激活的可靠性和精确性。
11名女性业余跑步者分两次前往实验室。两次实验中，受试者均以三种速度（9.1、11和12千米/小时）各跑6分钟。
在每种速度下的最后两分钟同步记录耗氧量和肌电图数据。计算站立期下肢肌肉的时间协同激活情况。评估五块肌肉：股直肌、股外侧肌、股二头肌、胫骨前肌和腓骨外侧肌。
非参数相关性分析显示，每种速度下下肢肌肉协同激活与跑步代谢成本之间至少存在一种显著的正相关关系。胫骨前肌激活时长以及股二头肌 - 胫骨前肌和腓骨外侧肌 - 胫骨前肌的肌肉协同激活时长随速度增加而减少。
这些结果表明，近端肌肉（股直肌 - 股二头肌和股外侧肌 - 股二头肌）和腿部伸肌（股直肌 - 腓骨外侧肌）更长时间的协同激活与更高的跑步代谢成本相关，这可能对运动表现不利。随着速度加快，屈肌和远端肌肉协同激活减少是由于速度增加时胫骨前肌激活时长缩短，但仍可维持稳定性。
