Blood Flow Restriction Training for Treatment of Chronic Patellar Tendinopathy

Study Overview
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Brief Summary
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The purpose of this study is to investigate the clinical and functional outcome of a 12-week rehabilitation regime consisting of Low-Load Blood Flow Restriction compared to Heavy-Slow Resistance training in male patients with chronic unilateral patellar tendinopathy.

Detailed Description
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Chronic tendinopathy represents a considerable problem in both elite and recreational athletes, and symptoms may affect athletic performance and reduce or even result in retirement from sports participation. The current best treatment is considered to be heavy-slow resistance training (HSRT); however, not all patients are able to cope with heavy exercise loads. Therefore, low-load strength training performed under partial blood flow restriction may be a clinically relevant rehabilitation tool. This project aims to investigate a new innovative intervention to treat chronic unilateral patellar tendinopathy in male individuals using strength training with low-load muscle contractions performed under partial blood flow restriction (LL-BFR), and to compare the resulting treatment outcome to that of the current best practice (HSRT). Specifically, the effect of LL-BFR will be investigated using a randomized controlled trial design with two groups; 1) a low-load blood flow restriction training program, and 2) a heavy-load slow strength training program. A total sample size of 36 participants are needed when assuming a 10 % dropout. The training protocol consist of three weekly training sessions during a 12-week rehabilitation period. The primary outcome is measured using the Single-Leg Decline Squat at 12-week. If LL-BFR proves to be an effective treatment strategy for tendinopathy, it can easily be implemented in daily clinical practice.

Official Title
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The Effect of Low-Load Resistance Training With Blood Flow Restriction for Treatment of Chronic Patellar Tendinopathy - A Randomized Clinical Trial

Conditions
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Patellar Tendinopathy, Jumper's Knee

Intervention / Treatment
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* Other: Heavy-Slow Resistance training
* Other: Low-Load Blood Flow Restriction training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Unilateral patellar tendinopathy Chronic (symptoms >3 months) Pain of ≥ 4 during preferred sporting activity on the numerical pain rating scale (NRS; with 0 being no pain and 10 being the worst imaginable pain) Ultrasonographical tendon swelling Ultrasonographical hypo-echoic area with doppler Exclusion Criteria: Bilateral tendinopathy Cardiovascular diseases Diabetes Smoking Previous surgery or trauma to the knee joint with an effect on the presenting clinical condition Participants must not have been enrolled in a resistance based-rehabilitation program for the affected patellar tendon within the previous three months Previous corticosteroid injection for patellar tendinopathy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Heavy-Slow Resistance training<br>Heavy-Slow Resistance training. Three times weekly for 12 weeks. | Other: Heavy-Slow Resistance training<br>* Resistance training for knee extensors. The exercise will be performed at 80% of 1 RM and slowly (6 s/repetition).<br>|
| Experimental: Low-Load Blood Flow Restriction training<br>Low-Load Blood Flow Restriction training. Three times weekly for 12 weeks | Other: Low-Load Blood Flow Restriction training<br>* Resistance training for knee extensors. The exercise will be performed at 30% of 1 RM and with a relative Artery Occlusion Pressure of 80%<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline - 12 weeks using the clinical functional test Single-Leg Decline Squat measured on the Numerical Rating Scale (NRS; 0= no pain, 10 = worst imaginable pain) | Single-Leg Decline Squat is a reliable patellar tendon pain provocation test used to assess pain during function. | Baseline-12 weeks. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Single-Leg Decline Squat test | A reliable patellar tendon pain provocation test, will be used to assess pain during function using the Numerical Rating Scale (NRS; 0= no pain, 10 = worst imaginable pain) | Baseline, 3, 6 weeks + 1 year follow-up | 
| Pain rating on Numeric Rating Scale (NRS; 0 = no pain; 10 = worst imaginable pain) during training. |  | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Self-reported activity level of sporting activities (hours/week) | Participants will self-report how many hours a week they are performing sporting activities: We will monitor to see if they decrease, maintain or increase hours per week of sporting activity | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Doppler activity using Ultrasonography power Doppler | Using Ultrasonography, we will measure Doppler activity within the affected tendon and use ImageJ for the analysis | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Tendon thickness measured using Ultrasonography |  | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Muscle cross-sectional area measured using Ultrasonography | We will measure the muscle thickness of vastus lateralis using ultrasonography | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Muscle structure measured by MRI |  | Baseline and 12 weeks | 
| Tendon dimensions measured by MRI |  | Baseline and 12 weeks | 
| Isometric Muscle Strength | Maximal muscle strength of the knee extensors is obtained during a maximal isometric voluntary contractions | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Pain Pressure Threshold | Measured by a handheld pressure algometry at most painful site, Apex Patellar, Tibialis Anterior and Extensor Carpi Radialis. | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 
| Adverse events | Participants will self-report adverse events during intervention period and at 1 year follow-up | Baseline-12 weeks + 1 year follow-up | 
| Victorian Institute of Sports Assessment - Patellar Tendinopathy | The VISA-P is a questionnaire that assesses symptoms, simple test of function, and the ability to play sports. Max score for asymptomatic is 100 and worst score is 0 | Baseline, 3, 6 and 12 weeks + 1 year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Patellar tendinopathy, Overuse Injury, Rehabilitation