Exercise Therapy and Physical Activity Modification for Patients With Sever's Disease (SDX)

November 5, 2026 updated by: Shawn Hanlon, California State University, Fullerton

Exercise Therapy and Physical Activity Modification for Patients With Sever's Disease: A Randomized Controlled Trial

Sever's disease is an overuse injury to the calcaneal growth plate caused by repetitive traction stress from the Achilles tendon in youth. Limited evidence exists to guide effective treatment for Sever's disease and disrupt short- and long-term pain and disability. Exercise therapy has the strongest evidence to promote tissue healing and is supported for other growth plate injuries. This study aims to determine if a comprehensive exercise therapy and activity modification intervention produces a clinically meaningful improvement in (Aim 1) pain and lower extremity function, (Aim 2) muscle and tendon structure, and (Aim 3) physical activity, compared to a non-exercise palliative approach for patients with Sever's disease. Differences between groups after completing 12 weeks of intervention.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Sever's disease (calcaneal apophysitis) is a debilitating overuse injury to the calcaneal apophysis (growth plate) caused by repetitive traction stress on the growth plate. The condition occurs in 3.7 per 1,000 young patients, most commonly between ages 8-15 years old. Patients with Sever's disease experience months of heel pain with running and jumping activities, reduced quality of life, and struggle to participate in social and sports activities. Symptoms can progress from self-limiting to complete loss of function and may persist into adulthood, leading to early retirement from sport. Therefore, effective rehabilitation is essential to curb the substantial negative implications on physiological and psychological health that may continue into adulthood and contribute to healthcare utilization and global physical inactivity trends.

There is a lack of high-quality evidence to guide intervention for Sever's disease. Expert opinion maintains that pain and dysfunction resolve spontaneously when patients reach skeletal maturity. As a result, palliative interventions consisting of activity avoidance or cessation are often prescribed for symptom relief. At the tissue level, these passive strategies risk the healthy maturation of load-bearing tissues through physical activity (PA) in the most critical years of growth.Recent evidence of altered Achilles tendon structure in patients with Sever's disease suggests this condition may have lifelong implications. This underscores an immediate need to develop an evidence-based treatment strategy that supports tissue remodeling during this critical time of growth and encourages a physically active lifestyle in adulthood. Exercise therapy promotes tissue healing and is effective for patients with Achilles tendinopathy and other apophyseal injuries. Our pilot study determined that this treatment approach is feasible and safe for patients with Sever's disease and preliminary results support conducting a larger clinical trial to determine efficacy to improve clinical outcomes. We propose to conduct a 12-week randomized controlled trial to evaluate the effectiveness of a comprehensive tendon-loading protocol compared to a palliative control approach for treating Sever's disease. The experimental group (EXP) will receive a comprehensive intervention including a tendon-loading protocol and education on daily pain monitoring to allow continued sports participation within a tolerable pain range. The control group (CTL) will be instructed to participate in activities of daily life and sports as tolerated. Both groups will be provided gel heel cups and an activity diary. Both groups will be asked to don a wearable ActivPAL activity monitor for seven consecutive days after data collection at baseline, 6-, and 12- weeks. Our specific aims are: (1) To determine if the comprehensive intervention produces clinically meaningful improvement in symptom severity, lower extremity function, and psychosocial factors compared to palliative care over 12 weeks. (2) Evaluate changes in triceps surae and Achilles tendon morphology and mechanical properties over time. (3) Explore weekly PA volume and intensity at time of diagnosis and changes during intervention.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • California
      • Fullerton, California, United States, 92831
        • Recruiting
        • Kinesiology and Health Sciences Building
        • Contact:
        • Contact:
        • Principal Investigator:
          • Shawn L Hanlon, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

8 years to 17 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Insidious onset of heel pain over several weeks
  • Pain on palpation of the calcaneus or Achilles tendon
  • Complaint of heel pain with running or jumping activities.

Exclusion Criteria:

  • Any underlying condition predisposing heel pain (i.e., spina bifida, osteogenesis imperfecta, Larsen syndrome, cerebral palsy)
  • Any other injury that limits their ability to run or jump.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental Group

The experimental group will receive supervised progressive tendon-loading exercise therapy, pain-guided activity modification education, and feedback on daily activity. Both groups will receive gel heel cushion inserts for footwear.
Behavioral: Exercise

Therapeutic Achilles-tendon loading exercise; Activity modification using a Pain Monitoring Model
Active Comparator: Control Group

The control group will not receive progressive tendon-loading exercise. The control group will receive the same education as the experimental group, except the control group will be asked to participate in activities as tolerated and rest as needed. The control group will be asked to record the same activity diary as the experimental group, but will not receive feedback on their daily activity. Both groups will receive gel heel cushion inserts for footwear.
Other: Active Control

Conventional Clinician advice for pediatric overuse injury management.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Self-reported Achilles tendon or heel pain and Symptoms with Activity
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

The Victorian Institute of Sport Assessment-Achilles (VISA-A) will be used. Survey completed via participant interview at baseline. Survey completed online by participants for follow-up visits.
Baseline, 6 weeks, and 12 weeks after randomization.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Single-leg Countermovement Jump Height
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

Participants will be instructed to keep their arms behind their back and jump as high as possible on a flat surface. Jump height will be measured in cm via the MuscleLab contact grid.
Baseline, 6 weeks, and 12 weeks after randomization.
Single-leg Drop Countermovement Jump Height
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

The drop CMJ is performed by standing on the edge of a 20cm box, then stepping off to land and immediately rebounding as high as possible. Jump height will be measured in cm via the MuscleLab contact grid.
Baseline, 6 weeks, and 12 weeks after randomization.
Total Heel-rise Work
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

The heel-rise endurance test is performed barefoot while standing on a single leg on a slant board fixed at 10 degrees of dorsiflexion. Participants will be instructed to perform as many heel-rises as possible while maintaining a straight knee and a slight forward lean, lifting the heel as high as possible, to a metronome set at 60 beats/min (30 heel-rises/min). Participants will place only two fingers from each hand on the wall to maintain balance. The test will conclude when the participant is unable maintain the test cadence, elect to stop due to fatigue or pain, or perform consistent repetitions with compensation. A linear encoder will be taped to the posterior calcaneus, which records linear displacement (heel-rise height, cm) for each repetition. Total heel-rise work will be calculated in Joules by summing the displacement for each repetition, multiplied by body mass and the force of gravity.
Baseline, 6 weeks, and 12 weeks after randomization.
Achilles Tendon Cross-sectional Area
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

B-mode ultrasound imaging (GE P9 Xdclear R4.5, GE Healthcare) will be used to assess the Achilles tendon cross-sectional area in short-axis images. CSA will be measured at the thickest portion of the free Achilles tendon.
Baseline, 6 weeks, and 12 weeks after randomization.
Shear Wave Velocity
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

Shear wave velocity (SWV) will be measured using Ultrasound Shear Wave Elastography. SWV is a measurement of resistance to deformation (stiffness) in tendon. Participants will be positioned prone, with legs past the mid-shank suspended over the edge of the exam table and feet resting against a custom wall-mounted slant board to fix the ankles at 15 degrees of dorsiflexion. The region of interest will be between the anterior-posterior borders of the Achilles tendon visualized on b-mode ultrasound imaging in longitudinal axis and centered over the thickest portion of the free Achilles tendon. This distance will be documented from the cephalad border of the Achilles tendon osteotendinous junction (calcaneal notch). In cases of uniform thickness, the ROI will be standardized to 2cm proximal to the calcaneal notch. The average of three trials will be analyzed.
Baseline, 6 weeks, and 12 weeks after randomization.
Achilles Tendon Echogenicity
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

The percentage of white to greyscale pixels (range 0-255) is calculated within a region of interest using the LAX Achilles tendon thickness images.
Baseline, 6 weeks, and 12 weeks after randomization.
Daily Step Count
Time Frame: 2 weeks before randomization, Baseline, 6 weeks, and 12 weeks after randomization.

Number of steps taken during waking hours measured using a wearable accelerometer- and inclinometer-based sensor (ActivPAL). Participants will wear the device continuously for 7 days at each study time point.
2 weeks before randomization, Baseline, 6 weeks, and 12 weeks after randomization.
Daily Activity Minutes
Time Frame: 2 weeks before randomization, Baseline, 6 weeks, and 12 weeks after randomization.

Daily minutes/day spent sitting, standing, stepping, and being sedentary will be averaged for each participant across all valid days using a wearable accelerometer- and inclinometer-based sensor (ActivPAL4+). Participants will wear the device continuously for 7 days at each study time point. Additionally, daily minutes at a moderate-to-vigorous activity stepping cadence will be analyzed.
2 weeks before randomization, Baseline, 6 weeks, and 12 weeks after randomization.
Foot and Ankle Outcome Score
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.

Assesses foot and ankle-related symptoms, function, participation, and quality of life
Baseline, 6 weeks, and 12 weeks after randomization.
Tampa Scale For Kinesiophobia
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.
Baseline, 6 weeks, and 12 weeks after randomization.
Oxford Foot And Ankle Questionnaire Child Version
Time Frame: Baseline, 6 weeks, and 12 weeks after randomization.
Baseline, 6 weeks, and 12 weeks after randomization.
Global Rating of Change
Time Frame: 6 weeks, and 12 weeks after randomization.

"Please rate the overall change in your condition from the time that you began the study until now." Measured on an 11-point likert scale, where -5 is "A very great deal worse", 0 is "No change", and +5 is "A very great deal better".
6 weeks, and 12 weeks after randomization.
Global Rating of Function
Time Frame: 6 weeks, and 12 weeks after randomization.

"On a scale of 0 - 100, please rate the use/function of your injured body part?" 0 is No Function/Unable to Use Injured Body Part, and 100 is ull Function/ Full use of Injured Body Part.
6 weeks, and 12 weeks after randomization.
Satisfaction
Time Frame: 6 weeks, and 12 weeks after randomization.

"How satisfied are you with the current use/function of your injured body part?" 0-10 scale, where 0 is "Not satisfied" and 10 is "Very satisfied".
6 weeks, and 12 weeks after randomization.
Patient Acceptable Symptom Scale
Time Frame: 6 weeks, and 12 weeks after randomization.

"Considering all the activities and sports you do each day, how much you hurt, and what you can do with and without pain, are you satisfied with your current condition?" Yes/No answer.
6 weeks, and 12 weeks after randomization.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

California State University, Fullerton

Investigators

  • Principal Investigator: Shawn L Hanlon, PhD, California State University, Fullerton

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 30, 2025

Primary Completion (Estimated)

July 1, 2028

Study Completion (Estimated)

July 1, 2028

Study Registration Dates

First Submitted

November 5, 2026

First Submitted That Met QC Criteria

November 5, 2026

First Posted (Actual)

November 10, 2026

Study Record Updates

Last Update Posted (Actual)

November 10, 2026

Last Update Submitted That Met QC Criteria

November 5, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HSR-25-26-54
  • #25NIP02 (Other Grant/Funding Number: National Athletic Trainers' Association Research and Education Foundation)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Data will be shared upon reasonable request as decided by the Principal Investigator.

IPD Sharing Time Frame

At the conclusion of data collection (est. July 31, 2028).

IPD Sharing Access Criteria

Data will be made publicly available no later than six months after the final publication.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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