Human Movement Biomechanics Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium.
Nantes Université, Mouvement - Interactions - Performance (MIP), Nantes, France.
Scand J Med Sci Sports. 2024 Jun;34(6):e14679. doi: 10.1111/sms.14679.
The 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.
Twenty-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.
Patients 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.
We 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.
跟腱由三个具有相互滑动能力的子腱组成。由于最佳的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起作用。本研究的目的是在等长收缩期间，比较无症状对照组和跟腱病患者跟腱内的腱内滑动差异，以及改变水平足部位置对两组跟腱内滑动的影响。
29 名参与者（13 名跟腱病和 16 名对照组）在脚趾中立位、30%最大自主收缩（MVC）和脚趾内收位和脚趾外展位以 60%MVC 进行等长跖屈收缩，在此期间记录超声图像。腱内滑动通过浅层到中层和中层到深层的相对位移来估计。
跟腱病患者的腱内滑动明显低于无症状对照组。对于两组的水平足部位置，脚趾外展位与脚趾中立位和脚趾外展位相比，滑动增加。
我们提供的证据表明，跟腱病患者的腱内滑动明显低于无症状对照组。由于腱内滑动是跟腱的一种生理特征，外部足部位置有望增加跟腱病患者的滑动，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可以刺激跟腱内的滑动并改善临床结果。
