Gait retraining using haptic biofeedback medially shifts the center of pressure (COP) while walking in orthopedic populations. However, the ideal sensor location needed to effectively shift COP medially has not been identified in people with chronic ankle instability (CAI). Can a heel sensor location feasibly be employed in people with CAI without negatively altering kinematics? Does a heel sensor placement relative to the 5th metatarsal head (5MH) impact COP location while walking in people with CAI? In this exploratory crossover study, 10 participants with CAI walked on a treadmill with vibration feedback for 10 minutes with a plantar pressure sensor under the heel and 5MH. Separate 2×2 repeated measures analyses of covariances (rmANCOVAs) were used to compare the averaged COP location and 3-D lower extremity kinematics from the first 10% of stance before and after training and between sensor locations. Baseline measures served as covariates to adjust for baseline differences. Feedback triggered by a heel sensor resulted in 40% of participants avoiding a heel strike. There were no significant main effects or interactions between time and sensor location on COP location when controlling for baseline COP (p>0.05). However, with the 5MH placement, participants displayed less ankle internal rotation(IR) (5MH/Heel: −4.12±0.00º/ −6.43±0.62º), less forefoot abduction (-4.29±0.00º/ −5.14±1.01º), more knee flexion (3.40±0.32º/ 0.14±0.57º), less knee external rotation (-10.95±0.00º/-11.24±1.48º), less hip extension (-0.20±0.00º/-1.42±1.05º), and less hip external rotation (3.12±0.00º/3.75±1.98º). A 5MH location may be more feasible based on difficulties maintaining heel strike when the sensor was under the heel. While no sensor location was statistically better at changing the COP, the 5MH location decreased proximal transverse plane motions making participants’ gait more like controls. Individual response variations support comprehensive lower extremity assessments and the need to identify responder profiles using sensory feedback in people with CAI.

中文翻译：

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传感器位置对慢性踝关节不稳定患者使用触觉反馈改变步态压力中心的影响

在骨科人群中行走时，使用触觉生物反馈进行步态再训练可将压力中心 (COP) 向内侧移动。然而，对于慢性踝关节不稳 (CAI) 患者，尚未确定有效向内侧移动 COP 所需的理想传感器位置。足跟传感器位置是否可以在 CAI 患者身上使用而不会对运动学产生负面影响？脚跟传感器相对于第五跖骨头 (5MH) 的放置是否会影响 CAI 患者行走时 COP 的位置？在这项探索性交叉研究中，10 名患有 CAI 的参与者在带有振动反馈的跑步机上行走 10 分钟，脚跟下方装有足底压力传感器，压力为 5MH。使用单独的 2×2 协方差重复测量分析 (rmANCOVA) 来比较训练前后以及传感器位置之间的前 10% 姿势的平均 COP 位置和 3-D 下肢运动学。基线测量作为协变量来调整基线差异。脚后跟传感器触发的反馈使 40% 的参与者避免了脚跟着地。当控制基线 COP 时，时间和传感器位置之间对 COP 位置没有显着的主效应或交互作用 (p>0.05)。然而，通过 5MH 放置，参与者表现出较少的踝关节内旋 (IR)（5MH/脚跟：−4.12±0.00°/−6.43±0.62°），前足外展较少（-4.29±0.00°/−5.14±1.01°） ，更多的膝关节屈曲（3.40±0.32°/ 0.14±0.57°），更少的膝关节外旋（-10.95±0.00°/-11.24±1.48°），更少的髋部伸展（-0.20±0.00°/-1.42±1.05°） ，以及较少的髋部外旋（3.12±0.00°/3.75±1.98°）。由于当传感器位于脚跟下方时难以保持脚跟着地，因此 5MH 位置可能更可行。虽然没有任何传感器位置在统计上能更好地改变 COP，但 5MH 位置减少了近端横向平面运动，使参与者的步态更像对照。个体反应差异支持全面的下肢评估以及利用 CAI 患者的感觉反馈来识别反应者概况的需要。