Department of Human Physiology, Gonzaga University , Spokane, USA.
Department of Human Performance and Recreation, Brigham Young University, Idaho , Rexburg, USA.
J Sports Sci. 2020 Oct;38(19):2236-2241. doi: 10.1080/02640414.2020.1776929. Epub 2020 Jun 18.
Surface compliance has been shown to affect leg stiffness and energetics. It is unknown if compliance differences between common treadmills would elicit such changes. Therefore, the purpose of this study was to determine if compliance design differences of common treadmills would affect the mechanics and energetics of running. Eleven runners ran at moderate, self-selected, matched belt speeds for three minutes on two treadmills: compliant (CT) and rigid (RT) decks. During the last minute of each trial, oxygen consumption and six markers describing the torso, thigh, shank and foot, and one marker to determine treadmill deflection were recorded. Leg stiffness, continuous relative phase (CRP) and CRP variability were calculated. Compared to RT, running on CT resulted in a significantly more compliant leg (8.591 kN•m > 9.063 kN•m), lower oxygen consumption (34.69 ml•kg•min <36.86 ml•kg•min), different coordination patterns and greater variability, particularly during the push-off phase. These results are inconsistent with the literature because the deck of CT rebounds back at the runner during the absorption phase and away from the runner during the push-off phase. Therefore, care should be taken when using treadmills for research and comparing mechanical and energetic measures between studies.
表面顺应性已被证明会影响腿部刚度和能量学。目前尚不清楚常见跑步机之间的顺应性差异是否会引起此类变化。因此，本研究的目的是确定常见跑步机的顺应性设计差异是否会影响跑步的力学和能量学。11 名跑步者在两种跑步机上以中等、自我选择、匹配的履带速度跑 3 分钟：顺应性（CT）和刚性（RT）履带。在每次试验的最后一分钟，记录氧气消耗和六个描述躯干、大腿、小腿和脚的标记物，以及一个确定跑步机挠度的标记物。计算腿部刚度、连续相对相位（CRP）和 CRP 可变性。与 RT 相比，在 CT 上跑步会导致腿部更具顺应性（8.591 kN•m > 9.063 kN•m），氧气消耗更低（34.69 ml•kg•min < 36.86 ml•kg•min），协调模式不同，变异性更大，特别是在推离阶段。这些结果与文献不一致，因为 CT 的履带在吸收阶段会向跑步者反弹，而在推离阶段则会远离跑步者。因此，在进行研究和比较不同研究之间的力学和能量学测量时，应谨慎使用跑步机。
