Applied Neuromechanics Research Laboratory, University of North Carolina at Greensboro, NC 27412, United States.
J Electromyogr Kinesiol. 2012 Feb;22(1):124-30. doi: 10.1016/j.jelekin.2011.11.001. Epub 2011 Dec 3.
To better understand methodological factors that alter landings strategies, we compared sagittal plane joint energetics during the initial landing phase of drop jumps (DJ) vs. drop landings (DL), and when shod vs. barefoot. Surface electromyography, kinematic and kinetic data were obtained on 10 males and 10 females during five consecutive drop landings and five consecutive drop jumps (0.45m) when shod and when barefoot. Energy absorption was greater in the DJ vs. DL (P=.002), due to increased energy absorption at the hip during the DJ. Joint stiffness/impedance was more affected by shoe condition, where overall stiffness/impedance was greater in shod compared to barefoot conditions (P=.036). Further, hip impedance was greater in shod vs. barefoot for the DL only (via increased peak hip extensor moment in DL), while ankle stiffness was greater in the barefoot vs. shod condition for the DJ only (via decreased joint excursion and increased peak joint moment in DJ vs. DL) (P=.011). DJ and DL place different neuromechanical demands upon the lower extremities, and shoe wear may alter impact forces that modulate stiffness/impedance strategies. The impact of these methodological differences should be considered when comparing landing biomechanics across studies.
为了更好地理解改变着陆策略的方法学因素，我们比较了单足跳（DJ）和落地跳（DL）初始着陆阶段矢状面关节能量，以及穿鞋和赤脚时的情况。在连续 5 次落地跳和连续 5 次落地跳（0.45m）时，我们对 10 名男性和 10 名女性进行了表面肌电图、运动学和动力学数据采集，他们分别穿鞋和赤脚。由于 DJ 时髋关节的能量吸收增加，因此 DJ 时的能量吸收大于 DL（P=.002）。关节刚度/阻抗受鞋的条件影响更大，与赤脚相比，穿鞋时整体刚度/阻抗更大（P=.036）。此外，仅在 DL 时，穿鞋的髋关节阻抗大于赤脚（通过增加 DL 中的髋关节伸肌峰值力矩），而仅在 DJ 时，赤脚的踝关节刚度大于穿鞋（通过减少关节运动和增加 DJ 与 DL 相比的关节峰值力矩）（P=.011）。DJ 和 DL 对下肢的神经力学要求不同，而穿鞋可能会改变调节刚度/阻抗策略的冲击力。在比较不同研究中的着陆生物力学时，应考虑这些方法学差异的影响。
