Influence of Boot Sole Type on Bone Mass Accretion in Female Adolescent Soccer Players.

Abstract

Soccer has been shown as a beneficial sport for adolescents in terms of bone mass acquisition. The high ground-reaction forces together with the high muscular tension that this sport provokes helps the bone to adapt and become stronger. The sole of the soccer boot is the place where ground-reaction forces break through the body, and it therefore might have an effect on bone adaptations. PURPOSE: To identify whether the different type of boot sole (Astro Turf: AT; Artificial Ground: AG) has any influence on the acquisition of bone mass throughout a season (9 months) in female adolescent soccer players. METHODS: Thirty female adolescent soccer players participated in the study (11.5-14 yr); 14 of them used AT, and 16 AG boots. Lower limbs bone mineral content (BMC), density (BMD) and lean mass were assessed using dual energy X-ray absorptiometry (DXA) at the beginning and end of the season. ANOVA for repeated measures using height, lean mass and maturational status as covariates were applied to evaluate differences in BMC and BMD acquisition in both by boot type, dominant and non-dominant legs. Adjusted percentages of change between beginning and end of season BMC y BMD values were also calculated, and a 2-independent samples t-test was applied to observe differences. RESULTS: No significant group by time interactions were found for any leg BMC or BMD. Tendencies towards greater increments in AT group compared with AG group were found in the non-dominant leg for both BMC (320 to 355g in AT vs. 341 to 365g in AG; p=0.07) and BMD (1.029 to 1.136g/cm2 in AT vs. 1.094 to 1.164g/cm2 in AG; p=0.06). Also, percentage of change in non-dominant leg BMD was higher in AT than in AG group (10.9 vs. 7.9%; p<0.05). CONCLUSION: It seems from the results obtained, that female adolescent soccer players using AT boots might have a minor extra beneficial effect of soccer in terms of bone mass, at least in the non-dominant leg (supporting/standing leg for passes, shoot, dribbling). Supported by the Spanish Ministerio de Economía y Competitividad (Project DEP 2012-32724).