“…In this cross-sectional study, the authors used a four-way decomposition mediation analysis method, which showed that moderate-to-vigorous physical activity had a positive controlled direct effect on TBLH-BMC, independent of free leptin and possibly through mechanical loading, in both girls and boys [1]. However, since their participants were predominantly of normal weight, these observations may not apply to overweight and obese children at different stages of puberty [1]. In the same spirit, the longitudinal study by Ludwa et al [2] followed a diverse sample of 180 children, aged 8-16 years, for 3 years, and showed that physical activity and BMI had a significant direct impact on bone properties and an additional indirect effect on muscle strength, which was the strongest predictor of bone speed with sound measurements.…”