Aging is associated with a distal-to-proximal shift in joint kinetics during walking. This plasticity of gait is amplified rather than attenuated in old adults with high physical capacity. Because running is associated with greater kinetic demands at the ankle, older individuals with more versus less lifetime running exposure may retain a larger proportion of their ankle kinetics. The purpose of the study was to compare lower-extremity joint kinetics during walking between middle-aged runners with high and low lifetime running exposure. Eighteen middle-aged runners (9 per group) participated. Joint kinetics were calculated from kinematic and ground reaction force data during overground walking at 1.3 m·s⁻¹ and compared between groups. High exposure runners produced 50% greater positive hip work (P = .03; Cohen d = 1.02) during walking compared with low exposure runners, but ankle kinetics were not different between groups. No other differences in joint kinetics or kinematics were observed between groups. These findings suggest that the age-related increase in hip joint kinetics during walking could be a compensatory gait strategy that is not attenuated by lifetime running exposure alone. Finally, the amount of lifetime running exposure did not affect ankle kinetics during walking in middle-aged runners.

衰老与行走过程中关节动力学从远端到近端的转变有关。在身体能力较高的老年人中，步态的可塑性会增强而不是减弱。由于跑步与脚踝处更大的动力学需求相关，因此一生中跑步暴露量较多或较少的老年人可能会保留较大比例的踝关节动力学。该研究的目的是比较终生跑步暴露量高和低的中年跑步者步行时的下肢关节动力学。十八名中年跑者（每组九人）参加。^{根据地面行走期间以 1.3 m·s -1 的}运动学和地面反作用力数据计算关节动力学，并在各组之间进行比较。 与低暴露跑步者相比，高暴露跑步者在步行过程中产生的髋部正功高出 50%（P  = .03；Cohen d = 1.02），但各组之间的踝关节动力学没有差异。各组之间没有观察到关节动力学或运动学的其他差异。这些发现表明，步行过程中髋关节动力学与年龄相关的增加可能是一种补偿性步态策略，不会因终生跑步暴露而减弱。最后，终生跑步暴露量不会影响中年跑步者行走时的脚踝动力学。