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

Not Applicable

Not yet recruiting

• Conditions: Achilles Tendinopathy; Patellar Tendinopathy; Plantar Fasciopathy

• Registration Number: NCT06774547
• Lead Sponsor: Aalborg University

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.

Study Timeline

• Status Verified: 2025-01
• Study Start: 2025-01
• Study First Submitted: 2025-01-03
• Study First Submitted QC: 2025-01-12
• Last Update Submitted: 2025-01-12
• Study First Posted: 2025-01-14
• Last Update Posted: 2025-01-14
• Primary Completion: 2027-04
• Study Completion: 2028-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 120

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Plyometric quotient	From baseline to the 12-week follow-up	The plyometric quotient is calculated by dividing the flight time by the contact time during single-leg hops and has good to excellent reliability. The test is performed on a force plate where the participant is instructed to perform 25 hops at a frequency of around two hops per second standing on their affected limb (or most symptomatic if they have bilateral symptoms). The first three and last two hops are excluded, which means that 20 hops are used to assess the flight time and contact time.

Secondary Outcome Measures

Name	Time	Method
Plyometric quotient	From baseline to the 52-week follow-up	The plyometric quotient is calculated by dividing the flight time by the contact time during single-leg hops and has good to excellent reliability. The test is performed on a force plate where the participant is instructed to perform 25 hops at a frequency of around two hops per second standing on their affected limb (or most symptomatic if they have bilateral symptoms). The first three and last two hops are excluded, which means that 20 hops are used to assess the flight time and contact time.
Dynamic strength	Baseline to the 12-week and 52-week follow-ups	Dynamic strength measured in knee extension and flexion and ankle plantar flexion by isokinetic dynamometry. The test is performed five times in each movement direction.
Drop countermovement jump height	From baseline to the 12-week and 52-week follow-ups	Measured in centimetres and derived from the hop test (see description of the primary outcome) on the force plate.
Drop countermovement contact time	From baseline to the 12-week and 52-week follow-ups	Measured in seconds and derived from the hop test (see description of the primary outcome) on the force plate.
Victorian Institute of Sports Assessment - Achilles (VISA-A)	Baseline to the 12-week and 52-week follow-ups	Questionnaire only for participants with Achilles tendinopathy. Total score ranges from 0 to 100, where 100 indicates no pain or dysfunction and 0 represents severe limitations
TENDINS-A	From baseline to the 12-week and 52-week follow-ups	Questionnaire only for participants with Achilles tendinopathy. The 13-item is scored between 0 and 100, with '0' representing a perfect score (no disability) and '100' representing complete disability.
Foot Health Status Questionnaire	Baseline to the 12-week and 52-week follow-ups	Questionnaire only for participants with plantar fasciopathy. Includes four core domains: foot pain, foot function, footwear, and general foot health.; Each domain is scored separately, ranging from 0 (poor foot health) to 100 (optimal foot health).
VISA-P	Baseline to the 12-week and 52-week follow-ups	Questionnaire only for participants with patellar tendinopathy. Total score ranges from 0 to 100, with 100 indicating optimal function and 0 reflecting severe dysfunction.
Global Rating of Change	During the 12-week and 52-week follow-ups	A 7-point numerical rating scale that evaluates participants' improvement compared to before treatment. Participants are dichotomised as improved if they rate themselves as 'much improved' or 'improved' (categories 6 and 7) and categorised as not improved if they rate themselves from 'slightly improved' to 'much worse' (categories 1 to 5)
Exercise compliance and fidelity	During the 12-week intervention.	Based on training diaries. Exercise compliance relates to whether the training sessions have been performed, and fidelity relates to whether the exercises have been performed as prescribed regarding the number of repetitions, sets, and intensity.
Rate of return to sport	During the 12-week and 52-week follow-ups	Measured by a self-developed questionnaire that includes questions regarding their physical performance and participation in sports
Adverse events	Throughout the time participants are enrolled (52 weeks)	Adverse events will be collected throughout the trial and graded 1 to 5 according to the Common Terminology Criteria for Adverse Events v4.03. Participants are asked to contact the responsible clinician as soon as they experience any adverse event.
Pressure pain thresholds	From baseline to the 12-week and 52-week follow-ups	Pressure pain thresholds measured by a pressure algometer on the tendon (Achilles or patella) or plantar fascia depending on the tendinopathy and the contralateral elbow. The test is performed with a handheld pressure algometer. The probe is placed perpendicular to the skin, and pressure is applied at a rate of 30 kPa/s. The participants are instructed to push the button of a hand-held switch when they first feel the sensation of pressure change to a sensation of pain, and the test is terminated
Re-injury	During the 12-week and 52-week follow-ups	Rate of re-injury measured using the modified Oslo Sports Trauma Research Centre (OSTRC) Overuse Injury Questionnaire.
Psychological readiness to return to sport	Baseline to the 12-week and 52-week follow-ups	Psychological readiness to return to sport measured by the Injury-Psychological Readiness to Return to Sport (I-PRRS) Scale. Participants respond to 10 items, depending on the version, related to confidence, emotional state, and readiness.; Each item is scored on a scale of 0 to 100. 0 = Not confident/ready at all. 100 = Fully confident/ready