Document Type : Research Article (s)
Authors
Department of Sport Sciences, Faculty of Human Sciences, Yasouj University, Yasouj, Iran
Abstract
Background: Children with developmental coordination disorder (DCD) are vulnerable to reduced bone mineral density (BMD), largely due to limited physical activity and diminished mechanical loading on the skeleton. The present study investigated the individual and combined impacts of calcium supplementation and weight-bearing exercise on femoral neck bone mineral density in children with developmental coordination disorder.
Methods: This was a quasi-experimental study with a pre-test–post-test design and a control group. The study was conducted in Yasouj, Iran between January and September 2025. Eighty boys aged 7–10 years with a clinical diagnosis of developmental coordination disorder (DCD) were randomly allocated to one of the four intervention groups: (1) training plus calcium (TR+ Ca+), (2) training only (TR+ Ca⁻), (3) calcium only (TR- Ca⁺), and (4) control (TR- Ca⁻). The interventions lasted for nine months, with training sessions conducted three times per week with 2 L/day of vitamin D‑fortified milk (providing 250 mg additional calcium). Femoral neck BMD was assessed using dual-energy X-ray absorptiometry (DXA) both prior to and following the intervention period. Within-group changes were analyzed using paired-sample t-tests, whereas between-group differences were assessed using independent-sample t-tests. Statistical significance was established at a threshold of P<0.05.
Results: At baseline, groups did not differ significantly in age, anthropometric characteristics, IQ, dietary calcium intake, or physical activity levels (P>0.05). However, paired-sample t-tests revealed significant BMD increases within all intervention groups—TR⁺ Ca⁺ (t=10.67, P<0.001, d=1.46), TR⁺ Ca⁻ (t=7.49, P=0.001, d=1.28), and TR⁻ Ca⁺ (t=4.98, P=0.004, d=0.83) — while the control group showed no significant change (P=0.24). Independent t-test comparisons confirmed that the combined intervention (TR⁺ Ca⁺) yielded significantly greater BMD gains than training alone (t=4.52, P=0.001), calcium alone (t=5.87, P<0.001), or control (t=7.23, P<0.001). Exercise alone also produced larger improvements than calcium supplementation alone (t=2.23, P=0.032).
Conclusions: The findings indicated that both exercise and calcium supplementation were effective individually; however, the combined intervention yielded the most significant improvement. Accordingly, the integration of weight‑bearing exercise with calcium supplementation may represent a practical and effective strategy for promoting bone health and preventing bone density loss in children with DCD.
Keywords
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