Boise State University.
J Appl Biomech. 2021 Apr 1;37(2):95-101. doi: 10.1123/jab.2020-0135. Epub 2020 Dec 26.
This study determined changes in lower limb joint stiffness when running with body-borne load, and whether they differ with stride or sex. Twenty males and 16 females had joint stiffness quantified when running (4.0 m/s) with body-borne load (20, 25, 30, and 35 kg) and 3 stride lengths (preferred or 15% longer and shorter). Lower limb joint stiffness, flexion range of motion (RoM), and peak flexion moment were submitted to a mixed-model analysis of variance. Knee and ankle stiffness increased 19% and 6% with load (P < .001, P = .049), but decreased 8% and 6% as stride lengthened (P = .004, P < .001). Decreased knee RoM (P < .001, 0.9°-2.7°) and increased knee (P = .007, up to 0.12 N.m/kg.m) and ankle (P = .013, up to 0.03 N.m/kg.m) flexion moment may stiffen joints with load. Greater knee (P < .001, 4.7°-5.4°) and ankle (P < .001, 2.6°-7.2°) flexion RoM may increase joint compliance with longer strides. Females exhibited 15% stiffer knee (P = .025) from larger reductions in knee RoM (4.3°-5.4°) with load than males (P < .004). Stiffer lower limb joints may elevate injury risk while running with load, especially for females.
本研究旨在确定负重跑步时下肢关节刚度的变化，以及其是否因步幅或性别而不同。20 名男性和 16 名女性在以 4.0m/s 的速度负重（20、25、30 和 35kg）和 3 种步幅（自身偏好或加长和缩短 15%）下跑步时，对关节刚度进行了量化。下肢关节刚度、膝关节屈伸活动范围（ROM）和膝关节最大屈曲力矩分别进行混合模型方差分析。随着负荷的增加，膝关节和踝关节的刚度分别增加了 19%和 6%（P<0.001，P=0.049），但随着步幅的延长，膝关节和踝关节的刚度分别降低了 8%和 6%（P=0.004，P<0.001）。膝关节屈伸 ROM 减小（P<0.001，0.9°-2.7°）和膝关节（P=0.007，最大增加 0.12N.m/kg.m）和踝关节（P=0.013，最大增加 0.03N.m/kg.m）的最大屈曲力矩的增加可能会使关节在负重时变得僵硬。较大的膝关节（P<0.001，4.7°-5.4°）和踝关节（P<0.001，2.6°-7.2°）屈伸 ROM 可能会随着步幅的延长增加关节的顺应性。女性在负重时膝关节屈伸 ROM 的减少幅度（4.3°-5.4°）比男性更大（P<0.004），因此膝关节的刚度增加了 15%（P=0.025）。负重跑步时下肢关节僵硬可能会增加受伤风险，尤其是对女性而言。
