Plenary Poster 29th Australian and New Zealand Bone and Mineral Society Annual Scientific Meeting 2019

Regional site-specific effects of exercise-derived impact and muscle-generated loads from the OPTIMA-Ex trial (#86)

Conor Lambert 1 2 , Belinda R Beck 1 2 3 , Amy T Harding 1 2 , Steven L Watson 1 2 , Benjamin K Weeks 1 2
  1. Menzies Health Institute Queensland, Griffith University, Gold Coast campus, Queensland, Australia
  2. School of Allied Health Sciences, Griffith University, Gold Coast campus, Queensland, Australia
  3. The Bone Clinic, Brisbane, Queensland, Australia

Exercise-derived loads are generally applied in one of two ways – impact-derived loads (e.g. landings and punching) and muscle forces (e.g. resistance exercise). Whilst each has merit as an osteogenic activity, it is unknown if the two approaches exert differential effects at different skeletal sites.

Aim: To compare the regional effects of high-intensity impact loading and high-intensity resistance training on bone mass and strength of upper and lower limbs of young women.

Methods: Sedentary young women (18-30 years) with below average bone mass were recruited. Testing included DXA- and pQCT-derived bone mineral density (BMD) and indices of bone strength of the dominant (D) and non-dominant (ND) upper and lower limbs. Participants completed supervised high-intensity impact (IT; n=10) and resistance training (RT; n=12) twice-weekly for 10 months (compliance: IT=61.4±15.1%, RT=66.4±11.2%, p=0.381). Statistical analysis involved one-way ANOVA to examine baseline differences and univariate ANOVA for percent change for dependent variables.

Results: Participant age differed between groups (IT=23.2±3.8 years, RT=20.5±1.8 years; p=0.042), but weight (IT=55.6±9.0 kg, RT=56.9±5.5 kg, p=0.872) and height (IT=165.7±6.5 cm, RT=163.5±6.5 cm, p=0.427) did not. pQCT-derived volumetric (v)BMD improved more following IT than RT at the ND distal radius (total vBMD=8.6±2.3% versus 1.5±2.0%, p=0.040; and trabecular vBMD=1.9±0.9% versus -1.3±0.8%, p=0.029) and the ND distal tibia (trabecular vBMD=1.2±0.6% versus -0.8±0.5%, p=0.017), as well as bone strength index (BSI) at the ND radius (15.4±2.8% versus 2.7±2.6, p=0.005), D tibia (total BSI 5.2±1.1% versus 0.4±1.0%, p=0.008; trabecular BSI=3.9±1.8% versus -2.8±1.6, p=0.014) and ND tibia (trabecular BSI=3.6 ±1.6% versus -3.2±1.5%, p=0.009). Conversely, RT improved DXA-derived cortical vBMD at the D femoral neck more than IT (3.7±2.0% versus -4.1±2.2%, p=0.021).

Conclusion: IT provided comparatively broader enhancement of the skeleton of young adult women, including trabecular and cortical indices of bone strength, while RT achieved a greater cortical bone response at the proximal femur.