Chitosan Phonophoresis With Recurrent Hamstring Strain in Athletes

Effectiveness of Chitosan Phonophoresis on Tissue Healing and Performance Related Outcomes in Athletes With Recurrent Hamstring Strain

The purpose of this randomized controlled trial is to evaluate and compare the effectiveness of adding chitosan phonophoresis as an adjunct to a rehabilitation-based exercise program compared to a rehabilitation-based exercise program with sham chitosan phonophoresis in athletes with recurrent hamstring strain injuries on the following outcomes: Hamstring-specific pain and function, Muscle strength and endurance, Lower extremity functions, Hamstring Flexibility symmetry and Hamstring injury healing score.

Study Overview

• Status: Enrolling by invitation
• Conditions: Hamstring Injury
• Intervention / Treatment: Combination product: CHITOSAN PHONOPHORESIS; Combination product: cham phonophoresis

Detailed Description

Hamstring injuries represent one of the most prevalent and recurrent soft tissue injuries in athletes, accounting for a significant percentage of time lost from training and competition across a variety of sports disciplines. These injuries encompass a spectrum of diagnoses, including muscle strains, proximal tendon avulsions, tendinopathies, and referred posterior thigh pain. The prevalence of recurrent hamstring strain injuries varies widely in studies, ranging from about 12% to as high as 63%. On average, recurrent hamstring strains account for around 26% of all hamstring injuries in sports such as Australian football, soccer, and rugby.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt
    • Cairo Uneversity

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Participants will be included in the study if they fulfil the following criteria:

1. Male recreational football players who participate in non-professional football training or matches for at least two sessions per week (each session ≥ 45 minutes) for at least the previous 12 months
2. Aged 18-35 years
3. Clinically diagnosed with a new episode of acute unilateral recurrent hamstring strain. Recurrent injury is defined as a new acute hamstring injury in the same limb and muscle group (biceps femoris, semitendinosus, or semimembranosus) as at least one previous hamstring strain that was professionally diagnosed, treated with rehabilitation, and after which the athlete returned to full participation. The previous injury must have occurred within the last 24 months
4. Current injury onset within 3-10 days of enrollment.
5. Current injury classified as Peetrons grade I or II on diagnostic musculoskeletal ultrasound performed within 7 days of enrollment by a single sonographer with at least 5 years of experience, using a 12-18 MHz linear probe in prone position (Peetrons, 2002; Heiss et al., 2025). The specific muscle involved, location within the muscle, and lesion volume (π/6 × L × W × D) will be documented at baseline
6. VISA-H score ≤ 75 at screening
7. Body mass index between 18.5 and 30.0 kg/m².
8. Able to walk independently without an assistive device.

Exclusion Criteria:

Participants will be excluded if they have any of the following:

1. History of hamstring tendon avulsion (complete or partial) or surgical repair in either limb.
2. Hamstring strain injury in the contralateral limb within the previous 12 months.
3. Concomitant lower extremity or lumbopelvic pathology that prevents safe completion of testing at maximal effort, including but not limited to knee ligament injury, meniscal injury, hip labral pathology, sacroiliac joint dysfunction, or lumbar disc herniation with radiculopathy.
4. Neurological disorder affecting lower extremity motor or sensory function such as peripheral neuropathy, lumbar radiculopathy, or multiple sclerosis.
5. Known allergy or hypersensitivity to chitosan, chitin, or shellfish, identified by self-report on a standardized allergy screening questionnaire at enrollment
6. Active skin disease, open wounds, or dermatitis over the posterior thigh of the affected limb.
7. Corticosteroid injection to the ipsilateral hamstring within the previous 6 months
8. Systemic conditions impairing healing such as diabetes mellitus, immunosuppressive therapy, chronic kidney disease, autoimmune connective tissue disorders, or coagulation disorders.
9. Use of pharmacological agents or supplements with known effects on tissue healing (such as growth hormone, anabolic steroids, or collagen supplements) within the previous 3 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention group; exercise-based rehabilitation program + chitosan phonophoresis	Combination product: CHITOSAN PHONOPHORESIS; All participants will receive a standardized, criterion-based hamstring rehab, after a session included therapeutic ultrasound using chitosan phonophoresis. Each category contained two different exercises to offer more variability. The two categories will be trained alternately. All exercises will be organized in five or six progressive levels with increasing physical and cognitive difficulty, and will be required to be performed in order (from 1 to 5/6). The exercises start on the first level and move to the next one when exercises are executed with a proper technique, as assessed by the therapist. The program takes about 15-20 minutes to complete after familiarization (3 sessions/week, clinic-supervised, 6 weeks).
Sham Comparator: Control group; exercise-based rehabilitation program + sham chitosan phonophoresis	Combination product: cham phonophoresis; All participants will receive a standardized, criterion-based hamstring rehab, after a session included therapeutic ultrasound using cham phonophoresis. Each category contained two different exercises to offer more variability. The two categories will be trained alternately. All exercises will be organized in five or six progressive levels with increasing physical and cognitive difficulty, and will be required to be performed in order (from 1 to 5/6). The exercises start on the first level and move to the next one when exercises are executed with a proper technique, as assessed by the therapist. The program takes about 15-20 minutes to complete after familiarization (3 sessions/week, clinic-supervised, 6 weeks).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Peetrons Classification System	The system consists of four grades (from 0 to 3) which describe the structural integrity of the muscle as seen on diagnostic ultrasonography	baseline
Victorian Institute of Sport Assessment - Hamstring	The Victorian Institute of Sport Assessment - Hamstring is a self-administered questionnaire developed to quantify the severity of symptoms, functional limitations, and sporting disability associated with hamstring injuries	baseline and 6 weeks post intervention
Single-Leg Hamstring Bridge Test	The Single-Leg Hamstring Bridge Test will be used to evaluate the effectiveness of rehabilitation protocols that reflect hamstring strength	baseline and 6 weeks post intervention
Lower Extremity Functional Test	The Lower Extremity Functional Test is performance-based test designed to assess athletic fitness, fatigue resistance, agility, speed, and neuromuscular control of the lower limbs	baseline and 6 weeks post intervention
Active Knee Extension Test	The Active Knee Extension Test is excellent in symptomatic and healthy (ICC often ≥0.90), used with an inclinometer	baseline and 6 weeks post intervention

Collaborators and Investigators

• Sponsor: Cairo University
• Investigators: Study Director: nasr abdelkader, PhD, cairo universoty

Publications and helpful links

Helpful Links

• references list

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: April 8, 2026
• First Submitted That Met QC Criteria: April 19, 2026
• First Posted (Actual): April 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: chitosan nanoparticles; hamstring strain
• Other Study ID Numbers: chitosan with hamstring strain

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No