Effects of Judo Training on Bones: A Systematic Literature Review

The aim of this study was to provide a systematic literature review on the osteogenic effects of judo (PROSPERO: CRD42016041803). The online search was conducted according to the inclusion criteria: observational studies and clinical/interventional trials in English from inception to June 2016; bone health, bone mineral density (BMD), diameters, impact force, and bone turnover marker (BTM) outcomes. Thirty-four studies were included and graded for their methodological quality ("fair" quality: 79.4%). The most used assessment method (44.1%) was X-ray absorptiometry. A positive association between judo and bone health/status emerged. Findings support site-specific BMD accrual in children, adolescents, adult athletes, and in premenopausal and postmenopausal female practitioners. Bone turnover markers revealed a hypermetabolic status in high-level judo athletes. The osteogenic stimuli of judo seem to protect athletes from alterations in bone metabolic balance due to weight loss cycling. Sexual dimorphism was found between judoka in bone diameters and mass, and significant differences in bone breadths emerged between elite and nonelite judokas. The fall techniques reduced bone impact force and velocity with respect to "natural" fall. Further longitudinal, cross-sectional, and interventional researches are required. This article provides useful information on bone for health sport scientists, coaches, and practitioners, stimulating future research lines on judo. In particular, coaches and physical trainers should consider introducing judo fall techniques in their training plans to prevent fall-related injuries, especially relevant in the older population. Conversely, coaches are urged to carefully control weight cycling dietary habits of their athletes, which can produce serious metabolic responses on bones.