Residual Eccentric Strength Deficits and Deep Scar Tissue Thickness in Patients With Tennis Leg

Summary

This study investigates the relationship between the thickness of deep scar tissue and residual weakness in the calf muscles of patients who have recovered from a condition known as "tennis leg." Tennis leg is a common calf muscle injury caused by a partial tear of the inner part of the gastrocnemius (calf) muscle at the point where muscle meets tendon. While patients often return to daily activities after healing, many continue to experience hidden weakness in their calf muscles, particularly during activities that require the muscle to lengthen under load (eccentric contractions), such as walking downhill, running, or landing from a jump.

This study uses diagnostic ultrasound imaging to measure the thickness of scar tissue that forms inside the muscle after injury. It also uses an isokinetic dynamometer to objectively measure the eccentric (lengthening) strength of the calf muscles. By comparing the injured leg to the uninjured leg in the same person, the study determines whether patients with thicker scar tissue have greater residual strength deficits.

The study enrolls adults aged 18 to 40 years who have had a confirmed unilateral calf muscle tear at least 3 months ago and have returned to normal daily activities. No treatment or intervention is provided. All assessments are performed at a single time point. Understanding how scar tissue relates to persistent muscle weakness could help clinicians better predict long-term outcomes, design more effective rehabilitation programs, and make more informed decisions about when patients are ready to return to sport and physical activity.

Conditions

• Tennis Leg
• Muscle Contusion

Interventions

DIAGNOSTIC_TEST

B-mode Diagnostic Ultrasound - Scar Tissue Assessment

B-mode diagnostic ultrasound is used to measure deep scar tissue thickness (in millimeters) at the musculotendinous junction of the medial gastrocnemius muscle. Measurements are obtained in both longitudinal and transverse planes at the site of maximal scar thickness. The contralateral uninjured limb is measured for comparison. Assessments are performed by a blinded experienced sonographer using a standardized probe position. This is a diagnostic exposure measurement, not a therapeutic intervention.

DIAGNOSTIC_TEST

Isokinetic Dynamometry - Eccentric Plantar Flexor Strength Assessment

Eccentric plantar flexor strength is assessed using an isokinetic dynamometer at angular velocities of 30°/s and 60°/s. Peak torque (Nm) is recorded for both the injured and uninjured limbs. Testing follows a standardized warm-up protocol with randomized testing order and adequate rest between trials. The percentage deficit between limbs is calculated. This is a diagnostic measurement, not a therapeutic intervention.

Sponsors & Collaborators

• Cairo University

  collaborator OTHER

• Al Hayah University In Cairo

  lead OTHER

Principal Investigators

• Haitham M. ElHafez, Ph.D · Cairo University

• Aya A Said, Ph.D · Cairo University

Eligibility

Min Age

18 Years

Max Age

40 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-04-15

Primary Completion

2026-08-15

Completion

2026-08-15

Countries

• Egypt

Study Locations