BACKGROUND: Patellar tendinopathy is a major problem for many athletes, especially those involved in jumping activities. Despite its frequency and negative impact on athletic careers, no evidence-based guidelines for management of this overuse injury exist. Since functional outcomes of conservative and surgical treatments remain suboptimal, new diagnostic and therapeutic strategies have to be developed and evaluated. Extracorporeal shockwave therapy (ESWT) appears to be a promising treatment in patients with chronic patellar tendinopathy. ESWT is most often applied after the known conservative treatments have failed. However, its effectiveness as primary therapy has not been studied in athletes who keep playing sports despite having patellar tendon pain. The aim of this study is to determine the effectiveness of ESWT in athletes with patellar tendinopathy who are still in training and competition. METHODS/DESIGN: The TOPGAME-study (Tendinopathy of Patella Groningen Amsterdam Maastricht ESWT) is a multicentre two-armed randomised controlled trial with blinded participants and outcome assessors, in which the effectiveness of patient-guided focussed ESWT treatment (compared to placebo ESWT) on pain reduction and recovery of function in athletes with patellar tendinopathy will be investigated. Participants are volleyball, handball and basketball players with symptoms of patellar tendinopathy for a minimum of 3 to a maximum duration of 12 months who are still able to train and compete. The intervention group receives three patient-guided focussed medium-energy density ESWT treatments without local anaesthesia at a weekly interval in the first half of the competition. The control group receives placebo treatment. The follow-up measurements take place 1, 12 and 22 weeks after the final ESWT or placebo treatment, when athletes are still in competition. Primary outcome measure is the VISA-P (Victorian Institute of Sport Assessment - patella) score. Data with regard to pain during function tests (jump tests and single-leg decline squat) and ultrasound characteristics are also collected. During the follow-up period participants also register pain, symptoms, sports participation, side effects of treatment and additional medical consumption in an internet-based diary. DISCUSSION: The TOPGAME-study is the first RCT to study the effectiveness of patient-guided ESWT in athletes with patellar tendinopathy who are still in training and competition. TRIAL REGISTRATION: Trial registration number NTR1408.