Purpose To compare the effects of high-intensity resistance and impact training (HiRIT) to low-intensity, Pilates-based exercise on proximal femoral geometry and explore the influence of antiresorptive medication on effects.
Methods Postmenopausal women with low bone mass, on or off antiresorptive bone medications, were recruited and randomly allocated, stratified on medication intake, to eight months of twice-weekly, supervised HiRIT (OneroTM) or supervised, low-intensity, Pilates-based exercise (BB, Buff Bones®). 3D hip software was used to analyse DXA scans of the non-dominant proximal femur. Outcomes included femoral neck (FN) and total hip (TH), volumetric bone mineral content (vBMC) and density (vBMD), and cortical thickness, and FN cross-sectional area, cross-sectional moment of inertia and section modulus (Z). Data were analysed using repeated measures analysis of variance.
Results Proximal femur scans of 102 women (64.7 ± 6.0 years) were examined: BB, 43; HiRIT, 37; BB-med, 11; HiRIT-med, 11. Exercise compliance did not differ between groups (83.4 ± 12.7%). HiRIT improved trabecular TH vBMC and vBMD (3.1 ± 1.1% versus -1.2 ± 1.2%, p = 0.008; and 1.5 ± 1.0% versus -1.6 ± 1.2%, p = 0.042, respectively) as well as total FN and TH vBMC (2.0 ± 0.8% versus -0.2 ± 0.7%, p = 0.032; and 0.7 ± 0.4% versus -0.8 ± 0.6%, p = 0.032, respectively), compared to losses in BB. HiRIT also increased Z while BB did not (p = 0.035). The combination of exercise and antiresorptive medication achieved greater improvements in multiple geometric outcomes compared to exercise alone, particularly for the HiRIT intervention.
Conclusions HiRIT provided a positive stimulus to geometric parameters of proximal femur strength while low-intensity, Pilates-based exercise was largely ineffective. Medication intake may enhance exercise effects, however, data are preliminary.