Muscle Architecture vs Alfredson Protocol in Achilles Tendinopathy

Summary

Achilles tendinopathy is a frequent overuse disorder caused by repetitive loading of the tendon, particularly observed in athletes and middle-aged men. It is typically characterized by mid-portion pain, stiffness in the morning, and functional limitations, with structural alterations such as thickening and disrupted collagen alignment. Chronic progression often compromises performance and quality of life.

Eccentric training protocols, such as the Alfredson regimen, are commonly prescribed but their standardized nature does not fully address individual variability. Alternative approaches including Heavy Slow Resistance training and progressive loading models (e.g., Silbernagel protocol) have demonstrated clinical effectiveness and higher patient adherence, yet they still apply uniform loading across the triceps surae without accounting for architectural differences.

Given the heterogeneous structure of the soleus and gastrocnemii, targeted loading strategies may be required to optimize tendon adaptation. To address this, the present study employs a muscle architecture-based exercise program tailored to the functional and structural properties of each muscle. Ultrasound imaging will be used to evaluate muscle-tendon morphology, while isokinetic dynamometry and functional performance tests will quantify outcomes. Pain (VAS) and functional capacity (VISA-A) will also be assessed.

This randomized controlled trial aims to compare the effectiveness of an architecture-specific program with the Alfredson protocol on tendon remodeling, strength, endurance, functional performance, and symptom reduction in individuals with non-insertional Achilles tendinopathy.

Conditions

• Achilles Tendinopathy (AT)
• Eccentric Exercise Training
• Muscle Architecture
• Isokinetic Test
• Ultrasound
• Balance
• Anaerobic Power

Interventions

OTHER

Muscle Architecture-Based Exercise Program

Participants in this arm will perform exercises specifically designed according to the architectural and functional properties of the triceps surae muscles. For example, knee-flexed positions will be used to target the soleus, while knee-extended positions will be emphasized for the gastrocnemii. Loading intensity and exercise progression will be tailored to optimize tendon and muscle remodeling.

OTHER

Alfredson Protocol

This intervention involves the traditional eccentric heel-drop program, originally developed for mid-portion Achilles tendinopathy. Participants perform three sets of 15 repetitions, twice daily, throughout the intervention period. Exercises are carried out both with the knee extended and flexed to load different portions of the triceps surae. The protocol applies repetitive eccentric loading to the Achilles tendon with the aim of stimulating collagen synthesis, reducing symptoms, and promoting tendon adaptation.

Sponsors & Collaborators

• Istanbul University

  collaborator OTHER

• Halic University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2025-10-15

Primary Completion

2026-12-15

Completion

2026-12-31

Countries

• Turkey (Türkiye)

Study Locations