Exercise for osteoporosis: how to navigate between overeagerness and defeatism.

Osteoporosis and associated fractures remain a common and costly health problem. Public fears about rare side effects of efficacious drug treatments for osteoporosis have contributed to decreased prescription and compliance. Exercise and physical activity-based interventions have long been proposed as an alternative treatment for osteoporosis. However despite compelling evidence from experimental studies in animals and from observational studies in humans, the use of exercise to improve bone mass in clinical practice does not seem to be justifiable by current human interventional studies. In this perspective, we summarise the available evidence in support of exercise on bone mass. We review the modest effects observed in current exercise trials, and propose a number of factors which may contribute to these discrepancies. We also highlight the successful application of exercise to attenuating or even partially reversing bone loss in musculoskeletal disuse. We then propose how collaboration between basic science and clinical partners, and consideration of factors such as exercise modality, exercise intensity and participation motivation could improve exercise efficacy.