Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, Place P. de Coubertin, 1, 1348, Louvain-la-Neuve, Belgium.
Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, 00133, Rome, Italy.
Eur J Appl Physiol. 2020 Jul;120(7):1575-1589. doi: 10.1007/s00421-020-04379-5. Epub 2020 May 11.
Much like running on a slope, running against/with a horizontal traction force which either hinders/aids the forward motion of the runner creates a shift in the positive and negative muscular work, which in turn modifies the bouncing mechanism of running. The purpose of the study is to (1) investigate the energy changes of the centre of mass and the storage/release of energy throughout the step during running associated with speed and increasing hindering and aiding traction forces; and (2) compare these changes to those observed when running on a slope.
Ground reaction forces were measured on eight subjects running on an instrumented treadmill against different traction forces at different speeds.
As compared to unperturbed running, running against/with a traction force increases/decreases positive external work by ~ 20-70% and decreases/increases negative work by ~ 40-60%, depending on speed and traction force. The external power to maintain forward motion against a traction is contained by increasing the pushing time and step frequency. When running with an aiding force, the external power during the brake is limited by increasing braking time. Furthermore, the aerial time is increased to reduce the power required to reset the limbs each step.
Our results show that the bouncing mechanism of running against/with a hindering/aiding traction force is equivalent to that of running on a positive/negative slope.
与在斜坡上跑步类似，与水平牵引力（阻碍/助力跑步者前进）一起跑步会改变正向和负向肌肉做功的分布，从而改变跑步的反弹机制。本研究的目的是：（1）研究在与速度和逐渐增大的阻碍/助力牵引力相关的跑步过程中，整个步幅阶段中质心的能量变化和能量的储存/释放；（2）将这些变化与在斜坡上跑步时的观察结果进行比较。
在仪器化跑步机上，对 8 名受试者进行地面反作用力测量，以不同速度在不同牵引力下跑步。
与未受干扰的跑步相比，在阻力/助力牵引力下跑步会使正向外部功增加/减少约 20-70%，负功减少/增加约 40-60%，具体取决于速度和牵引力。为了克服牵引力维持前进运动的外力，通过增加推蹬时间和步频来实现。当跑步时有助力时，通过增加制动时间来限制制动期间的外部功率。此外，增加腾空时间可以减少重置四肢所需的功率。
我们的结果表明，在阻力/助力牵引力下跑步的反弹机制与在正/负斜坡上跑步的反弹机制等效。
