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

Youth with low motor competence and poor bone health:  feasibility of a 13-week targeted exercise intervention on tibial bone outcomes as measured by peripheral Quantitative Computed Tomography (#113)

Paola T Chivers 1 2 3 , Jocelyn Tan 2 4 , Beth Hands 1 2 , Fleur McIntyre 2 4 , Nicolas Hart 1 2 3 , Timo Rantalainen 1 2 3 5 , Aris Siafarikas 1 2 3 6 7 8
  1. Institute for Health Research, The University of Notre Dame Australia, Fremantle, WESTERN AUSTRALIA, Australia
  2. Western Australian Bone Research Collaboration, Perth, Western Australia, Australia
  3. Exercise Medicine Research Institute , Edith Cowan University, Joondalup, Western Australia, Australia
  4. School of Health Science, The University of Notre Dame Australia, Fremantle, Western Australia, Australia
  5. Gerontology Research Centre, University of Jyvaskyla, Jyvaskyla, , Finland
  6. Department of Endocrinology and Diabetes, Perth Children's Hospital, Perth, Western Australia, Australia
  7. Telethon Kids Institute for Child Health Research, Perth, Western Australia, Australia
  8. Medical School, Division of Paediatrics, University of Western Australia, Nedlands, Western Australia, Australia

Objectives. Youth with low motor competence (LMC) have poor movement skills, reduced levels of physical activity and significantly lower bone mineral density (BMD) compared to their non-affected peers.  This feasibility study examined the impact of a 13-week exercise intervention on tibial bone parameters in youth with LMC.

Methods. Youth (n=28) with LMC participated in a 13-week intervention, two 90-minute sessions per week of cardiorespiratory, strength and resistance exercises.  Pre- and post-intervention bone parameter measures at the proximal (66%) and distal (4%) sites of the non-dominant tibia (T66 and T4) were measured using peripheral Quantitative Computed Tomography. The 1 Repetition Maximum (1RM) leg press, vertical jump and standing broad jump fitness tests and body mass index (BMI) were also examined pre- and post-intervention. Pre-Post differences were assessed using paired sample t-tests (or Wilcoxon signed-rank test), while generalised estimating equations (GEE) evaluated these changes whilst controlling for sex, pubertal stage, age, sessions attended and BMI.

Results. Seventeen boys and 11 girls, aged 12.6 years to 17.6 years (M=14.06, SD=1.28 years) were mid (n=14) or post (n=12) pubertal stages; (n=2 pre-pubertal). Significant increases post intervention were present for T66 mass (t(27)=2.75, p=.010, d=0.23), T66 cortical area (Z=2.45, p=.014, d=0.23), 1RM leg press (Z=2.78, p=.005, d=0.53), standing broad jump (t(27)=2.74, p=.011, d=0.15) and BMI (t(27)=2.30 p=.029, d=0.10). GEE models for T66 mass and cortical area, found these changes were significantly associated with the number of sessions attended, in addition to vertical jump and standing broad jump measures. 

Conclusion.  A short 13-week exercise intervention for youth with LMC demonstrates that some lower leg bone parameters respond and improve to targeted bone loading.  Given that this short intervention may not see the full effects of bone adaptation, targeted exercise with lower limb loading is feasible for improving bone health outcomes in youth with LMC.