Ekizos Antonis, Santuz Alessandro, Arampatzis Adamantios
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 11, 10115, Berlin, Germany; Berlin School of Movement Science, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 11, 10115, Berlin, Germany.
Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 11, 10115, Berlin, Germany; Berlin School of Movement Science, Humboldt-Universität zu Berlin, Philippstraße 13, Haus 11, 10115, Berlin, Germany.
Gait Posture. 2017 Jul;56:31-36. doi: 10.1016/j.gaitpost.2017.04.035. Epub 2017 Apr 27.
Barefoot running recently received increased attention, with controversial results regarding its effects on injury risk and performance. Numerous studies examined the kinetic and kinematic changes between the shod and the barefoot condition. Intrinsic parameters such as the local dynamic stability could provide new insight regarding neuromuscular control when immediately transitioning from one running condition to the other. We investigated the local dynamic stability during the change from shod to barefoot running. We further measured biomechanical parameters to examine the mechanisms governing this transition.
Twenty habitually shod, young and healthy participants ran on a pressure plate-equipped treadmill and alternated between shod and barefoot running. We calculated the largest Lyapunov exponents as a measure of errors in the control of the movement. Biomechanical parameters were also collected.
Local dynamic stability decreased significantly (d=0.41; 2.1%) during barefoot running indicating worse control over the movement. We measured higher cadence (d=0.35; 2.2%) and total flight time (d=0.58; 19%), lower total contact time (d=0.58; -5%), total vertical displacement (d=0.39; -4%), and vertical impulse (d=1.32; 11%) over the two minutes when running barefoot. The strike index changed significantly (d=1.29; 237%) towards the front of the foot.
Immediate transition from shod to the barefoot condition resulted in an increased instability and indicates a worst control over the movement. The increased instability was associated with biomechanical changes (i.e. foot strike patterns) of the participants in the barefoot condition. Possible reasons why this instability arises, might be traced in the stance phase and particularly in the push-off. The decreased stability might affect injury risk and performance.
赤脚跑步近来受到更多关注，但其对受伤风险和运动表现的影响结果存在争议。众多研究探讨了穿鞋与赤脚状态下的动力学和运动学变化。诸如局部动态稳定性等内在参数，在从一种跑步状态立即转换至另一种状态时，可为神经肌肉控制提供新的见解。我们研究了从穿鞋跑步转换至赤脚跑步过程中的局部动态稳定性。我们还测量了生物力学参数，以探究这种转换的机制。
20名习惯穿鞋的年轻健康参与者在配备压力板的跑步机上跑步，在穿鞋和赤脚跑步之间交替进行。我们计算了最大Lyapunov指数，作为运动控制误差的一种度量。还收集了生物力学参数。
在赤脚跑步期间，局部动态稳定性显著下降（d = 0.41；2.1%），表明对运动的控制变差。在赤脚跑步的两分钟内，我们测得步频更高（d = 0.35；2.2%）、总腾空时间更长（d = 0.58；19%）、总着地时间更短（d = 0.58； -5%）、总垂直位移更小（d = 0.39； -4%）以及垂直冲量更大（d = 1.32；11%）。触地指数显著变化（d = 1.29；237%），朝着脚掌前部变化。
从穿鞋状态立即转换至赤脚状态会导致不稳定性增加，并表明对运动的控制更差。不稳定性增加与参与者在赤脚状态下的生物力学变化（即触地模式）有关。这种不稳定性出现的可能原因，或许可在支撑阶段尤其是蹬离阶段找到。稳定性下降可能会影响受伤风险和运动表现。
