Early Implementation of Plyometric Exercises in the Rehabilitation of Individuals Suffering From Lower-Extremity Tendinopathies

NCT ID: NCT06774547

Last Updated: 2025-08-27

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 120 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-08-31
• Study Completion Date: 2028-01-31

Brief Summary

This clinical trial aims to compare the effectiveness of an early plyometric exercise approach with traditional heavy, slow resistance training in treating tendinopathies of the Achilles tendon, patellar tendon, and plantar fascia. These conditions, commonly seen in general and rheumatology practices, cause pain, reduced function, and stiffness, often leading to prolonged recovery and incomplete return to full physical activity. The study hypothesizes that introducing plyometric exercises early in rehabilitation will improve jump function after 12 weeks and reduce re-injury rates within 52 weeks compared to traditional methods.

The study is a randomized clinical trial including 120 participants aged 18-50 with tendinopathy in one of the targeted areas. Participants must regularly engage in running or jumping sports, have symptoms for at least three months, and meet other inclusion criteria. Exclusion criteria include recent surgery or specific medical conditions. Both groups will perform exercises three times weekly for 12 weeks, tailored to their tendinopathy. The intervention group will add progressive plyometric exercises to the standard strength training performed by the control group. Plyometric training will consist of three levels, with patients self-assessing readiness to progress.

The primary outcome is the change in the plyometric quotient, a measure of functional ability, based on a jump test using a force platform at 0 and 12 weeks. Secondary outcomes include dynamic strength, jump height, patient-reported symptoms (via questionnaires), return to sport, training compliance, adverse events, pain thresholds, re-injury rates, and psychological readiness for sports. Assessments will occur at baseline, 12 weeks, and 52 weeks.

Detailed Description

This trial is a randomised clinical trial with a 12-week intervention. The trial will be conducted at the Department of Physiotherapy, University College of Northern Denmark, Aalborg, Denmark. Participants will be stratified by their condition and block randomised (block sizes of 2 to 6) 1:1 to either 1) heavy-slow resistance training or 2) heavy-slow resistance training plus a plyometric exercise regimen. A researcher not involved in the trial will generate the allocation sequence using a random number generator and is the only person who will know the block sizes.

Conditions

Achilles Tendinopathy; Patellar Tendinopathy; Plantar Fasciopathy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Plyometrics

Performing both heavy-slow resistance training and the plyometric protocol

Group Type: EXPERIMENTAL

Heavy-slow resistance training

Intervention Type: OTHER

Heavy-slow resistance training consists of a progressive protocol of dynamic exercises where the relative load increases over time from a weight that can only be lifted 15 times (i.e., 15 repetition maximum) during the first week to a relative load of 6 repetition maximum from Week 9 to 12. The exercises are performed unsupervised three days per week separated by a minimum of 48 hours. There are two exercises that are performed for four sets separated by a 2-minute rest. Participants with Achilles tendinopathy or plantar fasciopathy perform seated and standing weighted heel raises and participants with patellar tendinopathy perform a free-standing squat and a seated leg press. Tolerable pain during the exercises is allowed.

Plyometric exercise

Intervention Type: OTHER

The progressive plyometric programme consists of three different levels and is performed unsupervised three times per week separated by a minimum of 48 hours. Each level consists of several exercise sets that are separated by 2-minute rest intervals. Participants' self-evaluated readiness to progress to a higher level will guide the progression. Level 1 includes free-standing double-legged plyometric exercises where they push off the ground and lift their heels while maintaining contact with it. If the participant feels they can do more, they will progress to Level 2, where participants increase the relative load during the dynamic exercises and start performing plyometric double-legged jumps. At the highest level, Level 3, the relative load during the exercises is further increased, and the plyometric exercises are to be performed as single-legged hops. Tolerable pain during the exercises is allowed.

Control

Perform heavy-slow resistance training

Group Type: ACTIVE_COMPARATOR

Heavy-slow resistance training

Intervention Type: OTHER

Heavy-slow resistance training consists of a progressive protocol of dynamic exercises where the relative load increases over time from a weight that can only be lifted 15 times (i.e., 15 repetition maximum) during the first week to a relative load of 6 repetition maximum from Week 9 to 12. The exercises are performed unsupervised three days per week separated by a minimum of 48 hours. There are two exercises that are performed for four sets separated by a 2-minute rest. Participants with Achilles tendinopathy or plantar fasciopathy perform seated and standing weighted heel raises and participants with patellar tendinopathy perform a free-standing squat and a seated leg press. Tolerable pain during the exercises is allowed.

Interventions

Heavy-slow resistance training

Heavy-slow resistance training consists of a progressive protocol of dynamic exercises where the relative load increases over time from a weight that can only be lifted 15 times (i.e., 15 repetition maximum) during the first week to a relative load of 6 repetition maximum from Week 9 to 12. The exercises are performed unsupervised three days per week separated by a minimum of 48 hours. There are two exercises that are performed for four sets separated by a 2-minute rest. Participants with Achilles tendinopathy or plantar fasciopathy perform seated and standing weighted heel raises and participants with patellar tendinopathy perform a free-standing squat and a seated leg press. Tolerable pain during the exercises is allowed.

Intervention Type: OTHER

Plyometric exercise

The progressive plyometric programme consists of three different levels and is performed unsupervised three times per week separated by a minimum of 48 hours. Each level consists of several exercise sets that are separated by 2-minute rest intervals. Participants' self-evaluated readiness to progress to a higher level will guide the progression. Level 1 includes free-standing double-legged plyometric exercises where they push off the ground and lift their heels while maintaining contact with it. If the participant feels they can do more, they will progress to Level 2, where participants increase the relative load during the dynamic exercises and start performing plyometric double-legged jumps. At the highest level, Level 3, the relative load during the exercises is further increased, and the plyometric exercises are to be performed as single-legged hops. Tolerable pain during the exercises is allowed.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

1. participants are required to perform either recreational running or participate in sports that include running or jumping activities (e.g., football, basketball, handball, volleyball) at least once per week for at least three months before inclusion

2. have had symptoms for at least three months

3. have pain/soreness with palpation of the tendon/fascia

4. mean pain during the past week of at least 2 on a 0 to 10 Numerical Rating Scale

5. pain during a pain provocation test (patellar tendinopathy: five single-legged decline squats, Achilles tendinopathy and plantar fasciopathy: ten single-legged heel raises)

Exclusion Criteria

1. previous lower-extremity surgery

2. other lower-extremity musculoskeletal conditions that have required treatment by a healthcare professional during the past three months

3. pregnancy

4. diabetes

5. history of inflammatory systemic diseases (e.g., rheumatoid arthritis or spondylarthritis)

6. having received an injection with corticosteroid within the past six months.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 50 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Department of Physiotherapy, University College of Northern Denmark

UNKNOWN

Sponsor Role: collaborator

Aalborg University

OTHER

Sponsor Role: lead

Responsible Party

Henrik Riel

Postdoc

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University College of Northern Denmark

Aalborg, , Denmark

Site Status: RECRUITING

Countries

Denmark

Central Contacts

Henrik Riel, PhD

Role: CONTACT

heri@ucn.dk

0045 72691014

Facility Contacts

Henrik Riel

Role: primary

heri@ucn.dk

0045 72691014

Other Identifiers

N-20240042

Identifier Type: -

Identifier Source: org_study_id