Chapman Andrew R, Vicenzino Bill, Blanch Peter, Dowlan Steve, Hodges Paul W
Division of Physiotherapy, The University of Queensland, Brisbane, Australia.
J Sci Med Sport. 2008 Jul;11(4):371-80. doi: 10.1016/j.jsams.2007.02.008. Epub 2007 Apr 26.
Triathletes report incoordination when running after cycling. We investigated the influence of the transition from cycling to running on leg movement and muscle recruitment during running in elite international level triathletes. Leg movement (three-dimensional kinematics) and tibialis anterior (TA) muscle activity (surface electromyography) were compared between a control-run (no prior exercise) and a 30-min transition-run (preceded by 20 min of cycling; i.e., run versus cycle-run). The role of fatigue in motor changes was also investigated. Leg kinematics were not different between control- and transition-runs in any triathlete. Recruitment of TA was different in 5 of 14 triathletes, in whom altered TA recruitment patterns during the transition-run were more similar to recruitment patterns of TA during cycling. Changes in TA recruitment during the transition-run were not associated with altered force production of TA or other leg muscles during isometric fatigue testing, or myoelectric indicators of fatigue (median frequency, average rectified value). These findings suggest that short periods of cycling do not influence running kinematics or TA muscle activity in most elite triathletes. However, our findings are evidence that leg muscle activity during running is influenced by cycling in at least some elite triathletes despite their years of training. This influence is not related to kinematic variations and is unlikely related to fatigue but may be a direct effect of cycling on motor commands for running.
铁人三项运动员报告称，在骑行后跑步时会出现动作不协调的情况。我们研究了从骑行转换到跑步对国际顶尖水平铁人三项运动员跑步时腿部运动和肌肉募集的影响。在对照跑步（无先前运动）和30分钟转换跑步（先进行20分钟骑行；即跑步与骑行后跑步）之间，比较了腿部运动（三维运动学）和胫前肌（TA）肌肉活动（表面肌电图）。还研究了疲劳在运动变化中的作用。在任何铁人三项运动员中，对照跑步和转换跑步之间的腿部运动学没有差异。14名铁人三项运动员中有5名的TA募集情况不同，在这些运动员中，转换跑步期间TA募集模式的改变更类似于骑行期间TA的募集模式。转换跑步期间TA募集的变化与等长疲劳测试期间TA或其他腿部肌肉的力量产生改变，或疲劳的肌电指标（中位频率、平均整流值）无关。这些发现表明，在大多数顶尖铁人三项运动员中，短时间的骑行不会影响跑步运动学或TA肌肉活动。然而，我们的研究结果证明，尽管经过多年训练，但至少在一些顶尖铁人三项运动员中，骑行会影响跑步时的腿部肌肉活动。这种影响与运动学变化无关，不太可能与疲劳有关，但可能是骑行对跑步运动指令的直接影响。
