アキレス腱症の患者は動的運動中に腱内の滑りが低下することを示す

Intra-tendinous sliding, i.e. non-uniform motions between the superficial and deep layers of the Achilles tendon, is reduced in individuals with Achilles tendinopathy compared to healthy controls during isometric contractions. Previous work has shown that intra-tendinous sliding can be increased by performing isometric contractions with a horizontally outward-rotated ("toes-out") foot position. The purpose of this study was to compare intra-tendinous sliding between healthy individuals and patients with Achilles tendinopathy during dynamic exercises, and to determine the effect of a toes-out foot position.

Forty participants (20 healthy and 20 Achilles tendinopathy) performed dynamic exercises, including bilateral heel rise/drop (sitting & standing), unilateral heel rise/drop (knee extended & bent) and squat. Exercises were performed in a neutral and toes-out foot position, with ultrasound images captured using an external probeholder. Intra-tendinous sliding (mm) was estimated via a speckle tracking algorithm as the difference between displacement of the superficial and deep layers of the Achilles tendon.

Main effects of group, foot position and exercise were found indicating that Achilles tendinopathy patients have reduced intra-tendinous sliding, that intra-tendinous sliding can be increased in a toes-out foot position and that some exercises induce more intra-tendinous sliding than others.

These findings support intra-tendinous sliding as a marker of tendon health and suggest that foot positioning may be a simple way to enhance sliding. Given the poor rehabilitation outcomes for Achilles tendinopathy patients, implementing an external foot position during rehabilitation protocols could offer a low-cost and easy-to-implement method to improve rehabilitation success rates.