Lower body bone mass characteristics of elite, sub-elite and amateur Australian footballers
Australian Strength and Conditioning Association
Faculty of Health, Engineering and Science
ECU Health and Wellness Institute/Centre for Exercise and Sports Science Research
Skeletal fragility is directly related to injury risk in football sports. Athletes with lower bone mass and slender bones are more vulnerable to impact fracture (trauma) and stress fracture (overuse) than athletes with greater bone mass and more robust bones. While the accrual of bone mass occurs most rapidly in teenage years, peak bone mass is not achieved until the mid-to-late twenties, providing strength and conditioning practitioners with an opportunity to improve an athlete’s resilience to hard-tissue injury at various stages of development. Mechanical loading induced by weight-bearing exercise and resistance training programs provide direct osteogenic effects to the skeleton, which lead to advantageous bone mass and bone strength adaptations at site-specific load-bearing regions (16,20). In particular, dynamic, explosive multi-planar activities which involve impact loads are considered to be highly osteogenic in nature due to the co-contribution of large muscle contraction forces, large ground reaction forces and rapid rates of change in forces which provide a greater stimulus to cells responsible for bone remodelling. This is particularly useful as even small (<2-fold) structural increases in bone can lead to major (>100-fold) improvements in bone fatigue resistance as a result of mechanical loading schemes. In Australian Football, athletes are routinely exposed to a variety of lower body loading patterns under training and competitive contexts, spanning from cyclical low-grade forces when walking or running, to sudden high-grade forces when jumping, landing, kicking or changing direction. The unpredictable and volatile nature of Australian Football therefore regularly produces compressive, torsional, transverse and tensile loads in combination and in isolation, which exposes footballers to stimuli that can lead to positive bone adaptations or in the absence of suitable strength and conditioning programs, an increased incidence of lower limb injuries. As Australian footballers engage in vastly different field-based and gym-based strength and conditioning programs across community, state and national competitions; it is the purpose of this paper to assess lower-body bone mass characteristics of elite, sub-elite and amateur Australian Football athletes in order to examine the influence of different loading schemes on lower body fragility or robustness across the developmental spectrum.