Shoulder impingement syndrome, more recently known as Sub-Acromial Pain Syndrome (SAPS), is a condition which affects a wide range of patients, and has an unclear aetiology. In part, the change in the name of the condition has been spurred by the fact that often, there is no objective evidence of actual impingement. In the absence of an operative rotator cuff tear, SAPS is often treated with non-operative modalities such as physiotherapy and injections. Eccentric exercise have been proposed as potentially beneficial for patients with SAPS, with the theory that they could reverse painful neo-vascularization of damaged tendons (demonstrated in Achilles tendinopathy). The authors in this study performed a meta-anlaysis of eight randomized controlled trials comparing eccentric exercise to a control in patients with shoulder impingement syndrome. Overall, 281 patients were included. Pain and function were assessed at short (6-8 weeks), medium (12 weeks) and long (6-12 months) term follow-up. The only statistically significant difference was observed for pain at 12 weeks, though even this did not reach the minimally important difference. Overall, there is little reason to believe that eccentric exercise provides a clinically meaningful change in patients with shoulder impingement/SAPS.