Contribuição das forças musculares isocinéticas de joelho e tronco para aquisição da massa óssea em atletas de futebol feminino / Contributions of knee and trunk isokinetic muscular strength to bone mass acquisition in female soccer players

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

OBJECTIVE: to analyze the contribution of isokinetic muscular strength of dominant knee and trunk flexors and extensors in the acquisition of bone mass in the correspondent regions that these forces are applied in female soccer players. METHODS: twenty-two female soccer athletes (GAF) were compared with 20 matched-controls (GC). The bone mineral content (BMC) and bone mineral density (BMD) were evaluated in whole body, lumbar spine and dominant hip (femoral neck and total hip) with the paediatric software of Hologic QDR (Discovery model, Bedford, MA, USA). From whole body scan, the variables of body composition and bone mass of dominant leg, trunk and head were also determined. The muscular strength of flexion and extension movements in dominant knee and trunk were evaluated with the Biodex Multi-joint System 3 (Shirley, NY, USA) with 60°/s, and 5 repetitions at concentric/eccentric mode. The concentric variables peak torque, maximal repetition total work and total work of flexors and extensors were considered. Statistical analysis was performed using Students t-test to compare groups and additionally Pearsons correlation coefficient and linear regression analysis to GAF. RESULTS: Both groups were similar regarding age, weight, height, race and calcium intake (p>0.05), however GAF presented a higher percentage of lean body mass and a lower percentage of body fat compared to GC (p<0.001). All loaded sites during exercise had significantly higher values of bone mass for GAF, and so for all isokinetic concentric strength variables of dominant knee and trunk (p<0.05 e p<0.001). Bone mass variables of GAF regions presented positive correlations with weight, body mass index, total and trunk lean mass. The BMD of any region presents significant correlations with variables of strength performance. Nevertheless, all strength variables of trunk flexors were positively correlated with BMC of whole body and trunk, so as knee dominant extensors with BMC of hip and dominant leg. CONCLUSION: muscular strength exerted a positive contribution to BMC acquisition at specifics sites. These results of positive correlation between force and bone mineral quantity of specific sites give us further evidences of the muscle strength role in the acquisition of regional bone mass.

ASSUNTO(S)

spine/physiology torque força muscular torque densidade óssea articulação do joelho/fisiologia muscle strength bone density women dinamômetro de força muscular mulheres soccer coluna vertebral/fisiologia futebol muscle strength dynamometer knee joint/physiology

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