The effect of weight-bearing exercise on the mechanisms of bone health in young females: A systematic review.

Weight-bearing exercise (WBE) has been identified as an appropriate approach for increasing peak bone mass, however, there is a lack of specific physical activity recommendations in this area. Thus, the aim of this systematic review is to determine the optimal mode of WBE, specifically identifying the intensity, duration, frequency, and load, to elicit the optimal effect on bone mass in young females, aged 5-18. A literature search was conducted from the 28^th of June to the 20^th of July 2021 using PubMed/Medline, Web of Science and SPORTDiscus. The search produced 1405 results, of which 15 were deemed appropriate for inclusion. The majority of studies (n=12) found a significant positive effect for at least one bone measure through their respective WBE exposure (p<0.05). Bone mass accrual was found to be site-specific depending on WBE exposure type, load, and maturity status. Also, longitudinal effects on bone mass accrual were found exclusively in gymnastics participants, even if participation level decreased (i.e., retirement). The results of this study support the use of WBE to improve parameters of bone health. However, further research is needed as the optimal mode of WBE to elicit the optimal effect on bone mass is still unclear.