Plain language summary
Fractures in older people are a huge public health challenge. Low bone strength in childhood is associated with a higher fracture risk in later life. Weight-bearing activities during childhood can improve muscle and bone strength, potentially reducing the risk of falls and fractures in later life. This study looked at the impact of frequent exercise sessions on bone strength in children aged 8-10 years. 295 Danish school children were divided into three groups: a small-sided ball game group (SSG), a circuit strength training group (CST) or a control group. Exercise sessions lasted for 40 minutes, three times a week for 10 months. Scans were used to determine bone mineral density (BMD), bone mineral content (BMC) and lean body mass (LBM). A variety of tests to determine muscular fitness were carried out at the beginning and end of the study. Both exercise groups saw significant improvements in BMD. Both training types resulted in significant improvements in postural balance and jump length. No differences between the groups were observed for sprint performance or LBM. The authors concluded that 40 min sessions 3 times a week with SSG or CST over a full school year improves bone mineralisation and several aspects of muscular fitness of children aged 8-10 years, suggesting that well-organised physical education classes can contribute positively to musculoskeletal health in young children.
Abstract
OBJECTIVES We investigated whether musculoskeletal fitness of school children aged 8-10 years was affected by frequent intense PE sessions. DESIGN AND PARTICIPANTS 295 Danish school children aged 8-10 years were cluster randomised to a small-sided ball game group (SSG) (n=96, four schools, five classes), a circuit strength training group (CST) (n=83, four schools, four classes) or a control group (CON, n=116, two schools, five classes). INTERVENTION SSG or CST was performed 3×40 min/week over 10 months. Whole-body dual-energy X-ray absorptiometry (DXA) scans were used to determine areal bone mineral density (aBMD), bone mineral content (BMC) and lean body mass (LBM). Flamingo balance, standing long jump and 20-m sprint tests were used to determine muscular fitness. RESULTS Analysis of baseline-to-10 months change scores showed between-group differences in favour of the interventions in whole-body aBMD (SSG vs CON: 8 mg/cm2, 95% CI 3 to 13; CST vs CON: 7 mg/cm2, 95% CI 2 to 13, p<0.05) and leg BMC (SSG vs CON: 11 g, 95% CI 4 to 18; CST vs CON: 11 g, 95% CI 3 to 18, p<0.05). SSG had higher change scores in leg aBMD compared with CON and CST (SSG vs CON: 19 mg/cm2, 95% CI 11 to 39, p<0.05; SSG vs CST: 12 mg/cm2, 95% CI 3 to 21, p<0.05), and CST had higher change scores in whole-body BMC compared with CON (CST vs CON: 25 g, 95% CI 10 to 39, p<0.05). Both training types resulted in higher change scores in postural balance (SSG vs CON: 2.4 fewer falls/min, 95% CI 0.3 to 4.5, CST vs CON: 3.6 fewer falls/min, 95% CI 1.3 to 5.9, p<0.05) and jump length (SSG vs CON: 10%, 95% CI 5 to 16%; CST vs CON: 9%, 95% CI 3 to 15%, p<0.05). No between-group differences were observed for sprint performance or LBM (p>0.05). CONCLUSIONS In conclusion, 3×40 min/week with SSG or CST over a full school year improves bone mineralisation and several aspects of muscular fitness of children aged 8-10 years, suggesting that well-organised intense physical education classes can contribute positively to develop musculoskeletal health in young children. TRIAL REGISTRATION NUMBER NCT02000492, post results.
Methodological quality
Jadad score
:
3
Allocation concealment
:
No
