Effectiviteit van excentrische oefentherapie bij patiënten met chronische midportion achillespees tendinopathie

1. Clinical diagnosis of "chronic midportion Achilles tendinopathy" based on the following criteria: a. Pain on palpation 2-7 cm above the insertion of the Achilles tendon (“midportion”) b. Achilles tendon symptoms for at least 2 months 2. Age 18-70 years

1. Clinical suspicion of insertional disorders (pain at the site of the insertion of the Achilles tendon on the calcaneus) 2. Clinical suspicion of an Achilles tendon rupture (Thompson test abnormal and/or palpable "gap") 3. Clinical suspicion of plantar flexor tenosynovitis (posteromedial pain when the toes are plantar flexed against resistance) 4. Clinical suspicion of sural nerve pathology (sensitive disorder in the area of the sural nerve) 5. Clinical suspicion of peroneal subluxation (visible luxation of the tendons of the Peroneal muscles at the lateral malleolus in combination with localized pain) 6. Condition of the Achilles tendon caused by medications (arising in relation to moment of intake), such as quinolones and statins 7. Patients known to have the following disorders: spondylarthropathy, gout, familial hypercholesterolemia and rheumatoid arthritis 8. The patient already performed heavy load eccentric calf muscle exercises for ≥4 weeks with a complete adherence to the protocol or a comparable absolute number of exercise sets (n = 5040) in the previous year 9. Presence of pregnancy 10. A condition that prevents the patients from executing an active rehabilitation program 11. Patient has received an injection for this injury 12. Patient has received surgical intervention for this injury 13. Patient has already one site (left or right) included in this study 14. Patient does not wish, for whatever reason, to undergo one of the two treatments 15. Patient has a history of Achilles tendon rupture on the affected