PurposeThe Achilles tendon consists of three subtendons with the ability to slide relative to each other. As optimal intratendinous sliding is thought to reduce the overall stress in the tendon, alterations in sliding behavior could potentially play a role in the development of Achilles tendinopathy. The aims of this study were to investigate the difference in intratendinous sliding within the Achilles tendon during isometric contractions between asymptomatic controls and patients with Achilles tendinopathy and the effect of changing the horizontal foot position on intratendinous sliding in both groups.MethodsTwenty‐nine participants (13 Achilles tendinopathy and 16 controls) performed isometric plantarflexion contractions at 60% of their maximal voluntary contraction (MVC), in toes‐neutral, and at 30% MVC in toes‐neutral, toes‐in, and toes‐out positions during which ultrasound images were recorded. Intratendinous sliding was estimated as the superficial‐to‐middle and middle‐to‐deep relative displacement.ResultsPatients with Achilles tendinopathy present lower intratendinous sliding than asymptomatic controls. Regarding the horizontal foot position in both groups, the toes‐out foot position resulted in increased sliding compared with both toes‐neutral and toes‐out foot position.ConclusionWe provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome.

中文翻译：

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无论脚的水平位置如何，主动跖屈期间跟腱病的腱内滑动都会减少


目的跟腱由三个能够相对滑动的子腱组成。由于最佳的肌腱内滑动被认为可以减少肌腱的整体应力，因此滑动行为的改变可能在跟腱病的发展中发挥作用。本研究的目的是调查无症状对照组和跟腱病患者等长收缩期间跟腱内肌腱内滑动的差异，以及改变水平足位置对两组肌腱内滑动的影响。方法29 名参与者（13跟腱病和 16 名对照组）在脚趾中立时以最大自主收缩 (MVC) 的 60% 进行等长跖屈收缩，在脚趾中立、脚趾向内和脚趾向外位置时以 30% MVC 进行等长跖屈收缩，在此期间进行超声图像被记录下来。腱内滑动被估计为浅层到中层和中层到深部的相对位移。结果跟腱病患者的腱内滑动程度低于无症状对照。关于两组的水平脚位置，与脚趾中立和脚趾向外的脚位置相比，脚趾向外的脚位置导致滑动增加。结论我们提供的证据表明，跟腱病患者比无症状对照组表现出较低的肌腱内滑动。由于腱内滑动是跟腱的一个生理特征，因此脚外侧位置有望增加跟腱病患者的滑动并促进健康的肌腱行为。 未来的研究应该调查在康复计划中实施这种外部足部位置是否会刺激跟腱内的滑动并改善临床结果。