Patellar Tendinopathy - The Effect of Load Magnitude in Exercise-based Treatment

Study Overview
=================
Brief Summary
-----------------
The purpose of this project is to investigate if the magnitude of a loading based 12 weeks rehabilitation regime for patellar tendinopathy influence the clinical outcome, tendon structure and function. The investigators hypothesize that a greater magnitude (90% of 1RM) of loading will yield a more positive clinical outcome, tendon structure and function in patients with patellar tendinopathy compared to a lower magnitude of loading (55% of 1 RM) when total exercise volume is equal in both groups.

Detailed Description
-----------------
Randomized controlled intervention study with one year follow-up

Official Title
-----------------
Treatment of Patellar Tendinopathy; Influence of Load Magnitude on Clinical Outcome, Tendon Structure and Function

Conditions
-----------------
Patellar Tendinopathy, Jumper's Knee

Intervention / Treatment
-----------------
* Other: Heavy slow resistance training
* Other: Moderate slow resistance training


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Uni- or bilateral patellar tendinopathy Symptoms > 3 months Ultrasonographical tendon swelling Ultrasonographical hypo-echoic area with doppler BMI 18.5-30 Exclusion Criteria: Patellar tendinopathy > 12 month Previous knee surgery Confounding diagnosis to the knee joint Diabetes or arthritis Previous corticosteroid injection for patellar tendinopathy Smoking Being elite volleyball players

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 45 Years

Sexes Eligible for Study
-----------------
Male

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

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 group<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 90% of 1 RM and slowly (6 s/repetition).<br>|
| Experimental: Moderate slow resistance group<br>Moderate slow resistance training. Three times weekly for 12 weeks. | Other: Moderate slow resistance training<br>* Resistance training for knee extensors. The exercise will be performed at 55% of 1 RM and slowly (6 s/repetition).<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline Victorian Institute of Sports Assessment - Patella Questionnaire (VISA-P) at 12 wks | Patient reported outcome regarding symptoms, function and the ability to participate in sports | 0-12 wks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Victorian Institute of Sports Assessment - Patella Questionnaire (VISA-P) | Patient reported outcome regarding symptoms, function and the ability to | 0 and 6 wks + 1 yr follow up + Long-term follow-up (2-4 yr) | 
| Pain rating on numeric rating scale (NRS) and activity level of sporting activities (h/wk) | Questionnaire | 0,6,12 wks + 1 yr follow up + Long-term follow-up (2-4 yr) | 
| Tendon thickness and Doppler activity | Measured by ultrasound | 0,6,12 wks + 1 yr follow up + Long-term follow-up (2-4 yr) | 
| Single-leg decline squat (SLDS) test | A reliable patellar tendon pain provocation test, will be used to assess pain during function | 0,6, 12 wks + 1 yr follow up + Long-term follow-up (2-4 yr) | 
| Jump test | Squat jump and Counter movement Jump will be used to assess patellar tendinopathy caused functional deficits on the injured site compared with the non-injured site | 0 and 12 wks | 
| Mechanical properties | Synchronized tendon elongation with the use of ultrasonography along with force measures, will be used during voluntary contractions to determine mechanical properties | 0 and 12 wks | 
| Muscle strength | Maximal muscle strength of the knee extensors is obtained during a maximal voluntary contractions | 0 and 12 wks | 
| Tendon dimensions and structure | Measured by MRI | 0 and 12 wks | 
| Treatment satisfaction | Questionnaire | 12 wks + 1 yr follow-up + Long-term follow-up (2-4 yr) |