Interaction between body composition and impact-related parameters in male and female heel-toe runners.

BACKGROUND: Bone fatigue resistance and more generally the ability to dissipate the stress sustained in dynamic tasks are partly affected by tissue properties. Men and women demonstrate substantial differences in body composition. RESEARCH QUESTION: To assess whether gender, as a function of body composition, affects impact-related parameters in running.
METHODS: A qualitative study has been conducted. Twelve females and eighteen males performed four 2-min running trials at 2.8 m∙s-1, 3.3 m∙s-1, 3.9 m∙s-1, and 4.4 m∙s-1 while recording axial and transverse tibial acceleration. Peak acceleration and power spectral density within the impact-related frequency range (vibration content) were measured. Bone mineral content, fat mass, lean mass, and muscle mass were assessed using an impedance meter. Two-way (gender × speed) ANOVAs were computed. Multiple linear regressions were then used to assess the magnitude of the effect of body composition indicators on impact-related parameters.
RESULTS: Significant gender and speed effects were observed. Females and high running speeds were associated with greater peak acceleration and vibration content at the tibia. Small interactions were observed between muscle mass and axial peak acceleration and vibration content, and between bone mineral content and transverse peak acceleration and vibration content, and axial vibration content. SIGNIFICANCE: Women demonstrated greater mechanical stress than men during running. High mechanical stress was associated with low bone mineral content and muscle mass. These findings may have implications in the prevention and management of bone overuse injuries in runners.