High-Intensity Exercise and Geometric Indices of Hip Bone Strength in Postmenopausal Women on or off Bone Medication: The MEDEX-OP Randomised Controlled Trial

Abstract

To compare the effects of high-intensity resistance and impact training (HiRIT) to low-intensity, Pilates-based exercise (LiPBE) on proximal femur geometry and explore the influence of antiresorptive medication on those effects. Postmenopausal women with low bone mass, on or off antiresorptive bone medications were randomly allocated, stratified on medication intake, to eight months of twice-weekly, supervised HiRIT (Onero™) or LiPBE (Buff Bones®). 3D hip software was used to analyse proximal femur DXA scans. Outcomes included femoral neck (FN) and total hip (TH), volumetric (e.g. vBMC, vBMD) and geometric (e.g. cortical thickness, cross-sectional area [CSA], section modulus [Z]) indices of bone strength. Data were analysed using analysis of variance. Scans of 102 women were examined: LiPBE, 43; HiRIT, 37; LiPBE-med, 11; HiRIT-med, 11. HiRIT improved TH trabecular 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) and FN and TH total 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 LiPBE. HiRIT also increased Z while LiPBE did not (p = 0.035). The combination of HiRIT and medication achieved greater improvements in FN total and trabecular vBMD, total BMC, CSA and Z than HiRIT alone. HiRIT improved geometric parameters of proximal femur strength, while LiPBE exercise was largely ineffective. Medication may enhance some HiRIT effects. Findings suggest reduced hip fracture risk in response to HiRIT.Trial registration number ACTRN12617001511325.

Keywords: Antiresorptive medication; Bone structure; Exercise; Hip fracture; Osteoporosis; Postmenopausal women.

Fig. 1

Eight-month percent change (mean ± SE) from exploratory subgroup analyses in femoral neck and total hip vBMC (a) and (b) and volume (c) and (d). ITT data; LiPBE n = 43, LiPBE-med n = 11, HiRIT = 37, HiRIT-med n = 11. * Indicates within-group change from baseline from RMANCOVA (p ≤ 0.05); FN femoral neck, HiRIT high-intensity resistance and impact training, HiRIT-med high-intensity resistance and impact training plus bone medications, ITT intention-to-treat, LiPBE low-intensity Pilates-based exercise, LiPBE-med low-intensity Pilates-based exercise plus bone medications, TH total hip, vBMC volumetric bone mineral content

Fig. 2

Eight-month percent change (mean ± SE) from exploratory subgroup analyses in femoral neck geometric (a) and cross-sectional (b) outcomes. ITT data; LiPBE n = 43, LiPBE-med n = 11, HiRIT = 37, HiRIT-med n = 11. * Indicates within-group change from baseline from RMANCOVA (p ≤ 0.05); CSA cross-sectional area, CSMI cross-sectional moment of inertia, HiRIT high-intensity resistance and impact training, HiRIT-med high-intensity resistance and impact training plus bone medications, ITT intention-to-treat, LiPBE low-intensity Pilates-based exercise, LiPBE-med low-intensity Pilates-based exercise plus bone medications, Z section modulus