Bone Abstracts

Objectives: Adolescents with Developmental Coordination Disorder (DCD) have significantly lower bone mineral density (BMD) compared to their non-affected peers. Their difficulty in performing weight bearing movement skills is hypothesised to explain poorer bone characteristics. This feasibility study examined the impact of a 13-week exercise intervention on tibial bone parameters in adolescents with DCD.

Methods: Twenty-eight adolescents with DCD participated in a 13-week intervention of cardiorespiratory, strength and resistance exercises for 90 minutes, twice per week. Lower limb bone parameters and fitness tests were measured pre- and post-intervention. Bone parameters included proximal (66%) and distal (4%) sites of the non-dominant tibia (T66 and T4) using peripheral Quantitative Computed Tomography. Fitness tests included the 1 Repetition Maximum leg press, vertical jump and standing broad jump. Paired sample t-tests (or Wilcoxon signed-rank test) examined pre-post differences. Generalised estimating Default (GEE) evaluated pre-post intervention changes whilst controlling for gender, pubertal stage, age, number of sessions attended and body mass index.

Results: Adolescents, 17 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=0.010, d=0.23), T66 cortical area (Z=2.45, P=0.014, d=0.23), 1RM leg press (Z=2.78, P=0.005, d=0.53), standing broad jump (t(27)=2.74, P=0.011, d=0.15) and BMI (t(27)=2.30 P=0.029, 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: Results suggest that for adolescents with DCD some bone parameters in the lower leg can respond to targeted bone loading exercise and improve, despite the short 13-week intervention and small effect sizes. Considering that effects of bone adaptation may not be fully appreciated in this short time, targeted exercise focussed on loading the lower limbs can improve bone health outcomes in this group. Further studies with a control group, larger sample and over a longer period of time are required to confirm positive changes to bone health, and determine whether optimal BMD scores similar to their non-affected peers can be achieved.

Disclosure: The authors declared no competing interests.