The Muscle-Bone Unit in Male Elite Soccer Players Aged 14-19

Background: Muscle and bone show reciprocal interactions and are associated in a muscle-bone unit. The muscle-bone unit has been investigated to a very limited extent in soccer players. The objective of this work was to investigate in detail the muscle-bone unit in male youth elite soccer players. Methods: Bone mineral and lean mass were measured with dual-energy X-ray absorptiometry (DXA). The functional muscle-bone unit (fMBU) and the muscle-to-bone ratio (MBR) were calculated from the DXA output in a sample of players aged 14-19 (n = 193) playing in the youth squads of an Italian Serie A team. Results: Statistically significant (p < 0.05) correlations were found between lean mass variables and bone mineral content and density, also after adjusting for age, body mass, stature, maturity, and ethnicity (White/Black). fMBU and MBR were statistically significantly associated with age, body mass, stature, maturity, and ethnicity. Linear regression showed that body lean mass was the strongest predictor for bone mineral content and density. Age was a statistically significant predictor for fMBU and MBR. Playing position did not show any statistically significant relationship with bone mineral content and density, as well as fMBU or MBR. Centiles for fMBU and MBR were calculated as a reference. Conclusions: This work is the first detailed characterization of the muscle-to-bone relationship in soccer players. It is expected to be of use for sport scientists and the wide community of sportsmen and professionals involved in soccer.