Eccentric Strengthening Exercises for Patellar Tendinopathy
Eccentric strengthening exercises are the cornerstone of treatment for patellar tendinopathy and should be implemented as first-line therapy before considering any other interventions. 1
The Specific Exercise Protocol
Perform eccentric squats on a decline board twice daily, with 3 sets of 15 repetitions per session, for a minimum of 12 weeks. 2
Technical Details of the Exercise
- Decline angle: Use either a 25-degree or 17-degree decline board—both angles produce equivalent clinical outcomes, so choose based on patient comfort and compliance 3
- Frequency: Twice daily (morning and evening) 2
- Volume: 3 sets of 15 repetitions per session 2
- Duration: Minimum 12-week intervention period before considering alternative treatments 2
- Progression: The exercise involves lowering the body weight eccentrically (lengthening phase) on the decline board 2
Why Eccentric Exercise Works
Eccentric loading stimulates collagen production and guides normal alignment of newly formed collagen fibers in the degenerative tendon, directly addressing the underlying pathophysiology of collagen disorientation and fiber separation 1, 4
Augmenting the Exercise Protocol
Add static stretching of the quadriceps and hamstrings to the eccentric training program—this combination produces superior outcomes compared to eccentric training alone. 5
- Perform static stretching exercises 5 times per week for 4 weeks 5
- This combination produces significantly better VISA-P scores both at the end of treatment (14-point improvement) and at 6-month follow-up (19-point improvement) compared to eccentric training alone 5
Critical Implementation Points
What to Avoid
- Never prescribe complete immobilization—this causes muscular atrophy and deconditioning 1
- Never inject corticosteroids directly into the tendon substance—this inhibits healing, reduces tensile strength, and predisposes to spontaneous rupture 1
Relative Rest Principle
- Reduce repetitive loading activities that reproduce pain (jumping, stair navigation) while maintaining the eccentric exercise program 1, 4
- This is "relative rest," not complete cessation of activity 1
Expected Timeline and Outcomes
- Initial improvement: Expect measurable improvement in VISA-P scores by 3 months 2
- Continued improvement: Scores continue to improve through 6 months and 12 months 2
- Success rate: Approximately 80% of patients recover completely within 3-6 months with appropriate conservative treatment 1
- Non-responders: If no improvement after 12 weeks of compliant eccentric training, consider secondary interventions 2
When Eccentric Exercise Fails
Only proceed to surgery after 3-6 months of well-executed conservative treatment has failed. 1, 6
- In one randomized trial, 5 out of 20 knees (25%) in the eccentric training group required secondary surgery after 3-6 months due to lack of response 2
- However, surgical treatment showed no advantage over eccentric training at 12-month follow-up in responders 2
Evidence Strength
The evidence for eccentric training is the strongest available for any patellar tendinopathy treatment 7. A 2012 systematic review found "strong evidence" for eccentric training, while all other interventions (surgery, sclerosing injections, shockwave therapy) had only "limited evidence" 7. A 2025 Cochrane review confirmed these findings but noted very low to low certainty evidence due to small sample sizes and methodological limitations 8.
Alternative Exercise Approaches
Heavy slow resistance training may serve as an alternative to eccentric training, with moderate evidence supporting its use 7. However, the specific eccentric decline board protocol remains the most extensively studied and recommended approach 9, 1, 7.