Exercise interventions for preventing and treating low bone mass in the forearm: A systematic review and meta-analysis.

To examine the effectiveness of exercises for improving forearm bone mass.MEDLINE, EMBASE, CINAHL, AMED, Web of Science, and Cochrane CENTRAL were searched from their inception till December 2018.Eligibility included adults undertaking upper-limb exercise interventions [≥12 weeks] to improve bone mass.Screening of titles/abstracts/full-texts and data extraction were undertaken independently by pairs of reviewers. Included studies were quality appraised using Cochrane risk of bias tool.Exercise interventions were classified into: 'resistance training' of high or low intensity (RTHI/RTLI, respectively), or 'impact'. Random-effects meta-analysis of the percentage change in forearm bone mass from baseline was conducted. Twenty-six studies were included in the review, of which 21 provided suitable data for meta-analysis. Methodological quality ranged from 'low' to 'unclear' risk of bias. Exercise generally led to increases (moderate-quality evidence) in forearm bone mass (standard mean difference [SMD]=1.27, 95% confidence interval [CI] =0.66, 1.88, overall effect Z-value=4.10, p<0.001). RTHI (SMD=1.00, 95% CI=0.37, 1.62, Z-value=3.11, p=0.002), and RTLI (SMD=2.36, 95% CI=0.37, 4.36, Z-value=2.33, p<0.001) led to moderate increases in forearm bone mass. Improvements due to impact exercises (SMD=1.12, 95%CI= -1.27, 3.50, Z-value=0.92, p=0.36) were not statistically significant (low-quality evidence).There is moderate-quality evidence that exercise is effective for improving forearm bone mass. There is moderate-quality evidence that upper body resistance exercise (RTHI/RTLI) promotes forearm bone mass, but low-quality evidence for impact exercise. Current evidence is equivocal regarding which exercise is most effective for improving forearm bone mass.