Bone density and cross-sectional geometry of the proximal femur are bilaterally elevated in elite cricket fast bowlers

The skeleton of a cricket fast bowler is exposed to a unique combination of gravitational and torsional loading in the form of substantial ground reaction forces delivered through the front landing foot, and anterior-posterior shear forces mediated by regional muscle contractions across the lumbo-pelvic region. The objectives of this study were to compare the hip structural characteristics of elite fast bowlers with recreationally-active age-matched controls, and to examine unilateral bone properties in fast bowlers. Dual-energy X-ray absorptiometry (DXA) of the proximal femur was performed in 26 elite male fast bowlers and 26 normally-active controls. Hip structural analysis (GE Lunar; enCORE version 15.0) determined areal bone mineral density (BMD) of the proximal femur, and cross-sectional area (CSA), section modulus (Z), cross-sectional moment of inertia (CSMI) and femoral strength index (FSI) at the narrow region of the femoral neck. Mean femoral neck and trochanter BMD were greater in fast bowlers than controls (p < 0.001). All bone geometry properties except for CSMI were superior in fast bowlers (p < 0.05) following adjustment for height and lean mass. There were no asymmetries in BMD or bone geometry when considering leg dominance of the fast bowlers (p > 0.05). Elite fast bowlers have superior bone characteristics of the proximal femur, with results inferring enhanced resistance to axial compression (CSA), and bending (Z) forces, and enhanced strength to withstand a fall impact as indicated by their higher FSI. No asymmetries in hip bone properties were identified, suggesting that both torsional and gravitational loading offer significant osteogenic potential.