School of Science and Technology, Nottingham Trent University, Nottingham, UK.
School of Science and Technology, Nottingham Trent University, Nottingham, UK; C-Motion, Inc., Germantown, MD, USA.
Gait Posture. 2022 Oct;98:153-159. doi: 10.1016/j.gaitpost.2022.09.008. Epub 2022 Sep 12.
Individuals with lower-limb amputation can use running specific prostheses (RSP) that store and then return elastic energy during stance. However, it is unclear whether varying the stiffness category of the same RSP affects spring-mass behaviour during self-selected, submaximal speed running in individuals with unilateral transtibial amputation.
The current study investigates how varying RSP stiffness affects limb stiffness, running performance, and associated joint kinetics in individuals with a unilateral transtibial amputation.
Kinematic and ground reaction force data were collected from eight males with unilateral transtibial amputation who ran at self-selected submaximal speeds along a 15 m runway in three RSP stiffness conditions; recommended habitual stiffness (HAB) and, following 10-minutes of familiarisation, stiffness categories above (+1) and below (-1) the HAB. Stance-phase centre of mass velocity, contact time, limb stiffness' and joint/RSP work were computed for each limb across RSP stiffness conditions.
With increased RSP stiffness, prosthetic limb stiffness increased, whilst intact limb stiffness decreased slightly (p<0.03). Centre of mass forward velocity during stance-phase (p<0.02) and contact time (p<0.04) were higher in the intact limb and lower in the prosthetic limb but were unaffected by RSP stiffness. Intact limb hip joint positive work increased for both the +1 and -1 conditions but remained unchanged across conditions in the prosthetic limb (p<0.02).
In response to changes in RSP stiffness, there were acute increased mechanical demands on the intact limb, reflecting a reliance on the intact limb during running. However, overall running speed was unaffected, suggesting participants acutely adapted to an RSP of a non-prescribed stiffness.
下肢截肢者可以使用特定的跑步假肢（RSP），这些假肢在站立时可以储存并释放弹性能量。然而，目前尚不清楚同一 RSP 的刚度类别变化是否会影响单侧胫骨截肢者在自主选择的亚最大速度跑步时的弹簧质量行为。
本研究调查了 RSP 刚度的变化如何影响单侧胫骨截肢者的肢体刚度、跑步性能和相关关节动力学。
从 8 名单侧胫骨截肢男性中收集了运动学和地面反作用力数据，他们在三个 RSP 刚度条件下以自主选择的亚最大速度在 15 米跑道上跑步；推荐的习惯刚度（HAB）以及在 10 分钟的熟悉后，刚度类别高于（+1）和低于（-1）HAB。在每个 RSP 刚度条件下，计算了每个肢体的支撑相质心速度、接触时间、肢体刚度和关节/RSP 功。
随着 RSP 刚度的增加，假肢肢体刚度增加，而完整肢体刚度略有下降（p<0.03）。支撑相质心前进速度（p<0.02）和接触时间（p<0.04）在完整肢体中较高，而在假肢肢体中较低，但不受 RSP 刚度的影响。在+1 和-1 两种情况下，完整肢体髋关节正功均增加，但在假肢肢体中在不同条件下保持不变（p<0.02）。
响应 RSP 刚度的变化，完整肢体承受急性机械需求增加，反映了在跑步过程中对完整肢体的依赖。然而，整体跑步速度不受影响，这表明参与者急性适应了非规定刚度的 RSP。
