Meinert Ilka, Brown Niklas, Alt Wilfried
Institute of Sport and Exercise Science, University of Stuttgart, Stuttgart, Germany.
PLoS One. 2016 Mar 24;11(3):e0152435. doi: 10.1371/journal.pone.0152435. eCollection 2016.
Achilles tendon injuries are known to commonly occur in runners. During running repeated impacts are transferred in axial direction along the lower leg, therefore possibly affecting the oscillation behavior of the Achilles tendon. The purpose of the present study was to explore the effects of different footwear modifications and different ground conditions (over ground versus treadmill) on oscillations at the Achilles tendon.
Oscillations were measured in 20 male runners using two tri-axial accelerometers. Participants ran in three different shoe types on a treadmill and over ground. Data analysis was limited to stance phase and performed in time and frequency space. Statistical comparison was conducted between oscillations in vertical and horizontal direction, between running shoes and between ground conditions (treadmill versus over ground running).
Differences in the oscillation behavior could be detected between measurement directions with peak accelerations in the vertical being lower than those in the horizontal direction, p < 0.01. Peak accelerations occurred earlier at the distal accelerometer than at the proximal one, p < 0.01. Average normalized power differed between running shoes (p < 0.01) with harder damping material resulting in higher power values. Little to no power attenuation was found between the two accelerometers. Oscillation behavior of the Achilles tendon is not influenced by ground condition.
Differences in shoe configurations may lead to variations in running technique and impact forces and therefore result in alterations of the vibration behavior at the Achilles tendon. The absence of power attenuation may have been caused by either a short distance between the two accelerometers or high stiffness of the tendon. High stiffness of the tendon will lead to complete transmission of the signal along the Achilles tendon and therefore no attenuation occurs.
跟腱损伤在跑步者中很常见。跑步时，反复的冲击力会沿小腿轴向传递，因此可能会影响跟腱的振荡行为。本研究的目的是探讨不同的鞋类改良和不同的地面条件（室外与跑步机）对跟腱振荡的影响。
使用两个三轴加速度计对20名男性跑步者的振荡情况进行测量。参与者穿着三种不同类型的鞋子在跑步机上和室外跑步。数据分析仅限于站立阶段，并在时间和频率空间中进行。对垂直和水平方向的振荡、跑鞋之间以及地面条件（跑步机与室外跑步）之间进行了统计比较。
在测量方向之间可以检测到振荡行为的差异，垂直方向的峰值加速度低于水平方向，p < 0.01。远端加速度计的峰值加速度比近端加速度计出现得更早，p < 0.01。不同跑鞋的平均归一化功率有所不同（p < 0.01），阻尼材料较硬的跑鞋功率值更高。两个加速度计之间几乎没有功率衰减。跟腱的振荡行为不受地面条件的影响。
鞋类配置的差异可能导致跑步技术和冲击力的变化，从而导致跟腱振动行为的改变。功率没有衰减可能是由于两个加速度计之间的距离较短或跟腱的高刚度所致。跟腱的高刚度将导致信号沿跟腱完全传输，因此不会发生衰减。
