Patients with Achilles Tendinopathy Show Reduced Intratendinous Sliding during Dynamic Exercises

Area of Science:

• Biomechanics
• Musculoskeletal Ultrasound
• Tendon Pathophysiology

Background:

• Intra-tendinous sliding, the differential motion between Achilles tendon layers, is reduced in Achilles tendinopathy.
• Previous research indicates isometric exercises with a toes-out foot position can enhance sliding.

Purpose of the Study:

• To compare intra-tendinous sliding in healthy individuals versus Achilles tendinopathy patients during dynamic exercises.
• To evaluate the impact of a toes-out foot position on intra-tendinous sliding in both groups.

Main Methods:

• Forty participants (20 healthy, 20 Achilles tendinopathy) performed dynamic exercises (heel rise/drop, squat) in neutral and toes-out positions.
• Ultrasound imaging and speckle tracking quantified intra-tendinous sliding (mm) based on superficial and deep layer displacement.
• Exercises included seated/standing heel rise/drop and single-leg heel rise/drop with knee extended/bent.

Main Results:

• Achilles tendinopathy patients exhibited significantly reduced intra-tendinous sliding compared to healthy controls.
• A toes-out foot position demonstrably increased intra-tendinous sliding across participants.
• Specific dynamic exercises elicited greater intra-tendinous sliding than others.

Conclusions:

• Intra-tendinous sliding serves as a potential biomarker for Achilles tendon health.
• Incorporating a toes-out foot position during rehabilitation may enhance sliding and improve outcomes for Achilles tendinopathy.
• This simple, low-cost modification offers a promising strategy for improving rehabilitation success rates.