Achilles tendinopathy has an aberrant strain response to eccentric exercise

Area of Science:

• Orthopedics
• Sports Medicine
• Biomedical Engineering

Background:

• Eccentric exercise is a primary treatment for Achilles tendinopathy.
• The acute effects of eccentric exercise on tendon mechanics and the underlying mechanisms of benefit are not fully understood.

Purpose of the Study:

• To investigate the sonographic characteristics and acute anteroposterior (AP) strain response of healthy, asymptomatic, and symptomatic Achilles tendons to eccentric exercise.

Main Methods:

• Sonographic assessments of Achilles tendon thickness, echogenicity, and AP strain were performed before and after eccentric exercise, and 24 hours later.
• Participants included eleven males with unilateral Achilles tendinopathy and nine healthy male controls.

Main Results:

• Baseline asymptomatic and symptomatic tendons were thicker and hypoechoic compared to controls.
• All tendons decreased in thickness immediately post-exercise, with thickness restored after 24 hours.
• Symptomatic tendons showed significantly lower AP strain response compared to asymptomatic and control tendons.

Conclusions:

• Achilles tendinopathy may be a bilateral or systemic condition.
• Structural changes in symptomatic tendons appear to alter intra-tendon fluid movement.
• Altered fluid dynamics could impair tendon remodeling and homeostasis, potentially driving tendinopathy progression.