The aim of this study was to evaluate a general school-based one-year exercise intervention program in a population-based cohort of girl at Tanner stage I. Fifty-three girls aged 7 to 9 years were included. The school curriculum based exercise intervention program included 40 minutes per school day. Fifty healthy age-matched girls assigned to the general school curriculum of 60 minutes physical activity per week served as controls. Bone mineral content (BMC; g) and areal bone mineral density (aBMD; g/cm 2 ) were measured with dual X-ray absorptiometry (DXA) of the total body (TB), lumbar spine (L2-L4 vertebra), the third lumbar vertebra (L3), the femoral neck (FN) and the leg. Volumetric bone mineral density (vBMD; g/cm 3 ) and bone width were calculated at L3 and FN. Total lean body mass and total fat mass were estimated from the total body scan. No differences were at baseline found in age, anthropometrics or bone parameters when the groups were compared. The annual gain in BMC was in the cases 4.7 percentage points higher in lumbar spine and 9.5 percentage points higher in L3 than in the controls (both p<0.001). The annual gain in aBMD was in the cases 2.8 percentage points higher in lumbar spine and 3.1 percentage points higher in L3 than in the controls (both p<0.001). The annual gain in bone width was in the cases 2.9 percentage points higher in L3 than in the controls (p<0.001).A general school-based exercise program in 7 -9-year-old girls enhances the accrual of BMC and aBMD and increases bone width.

This non-randomized prospective controlled study evaluates a daily school-based exercise intervention program of 40 min/school day for 1 year in a population-based cohort of 81 boys aged 7-9 years. Controls were 57 age-matched boys assigned to the general school curriculum of 60 min/week. Bone mineral content (BMC; g) and areal bone mineral density (aBMD; g/cm(2)) were measured with dual X-ray absorptiometry (DXA) of the total body, the third lumbar vertebra (L3) and the femoral neck (FN). Bone width for L3 and FN was calculated from the lumbar spine and hip scan. No differences between the groups were found at baseline in age, anthropometrics or bone parameters. The mean annual gain in L3 BMC was 5.9 percentage points higher (P<0.001), L3 aBMD a mean 2.1 percentage points higher (P=0.01) and L3 width a mean 2.3 percentage points higher (P=0.001) in the cases than in the controls. When all individuals were included in one cohort, the total duration of exercise including both school-based and spare-time training correlated with L3 BMC (r=0.26, P=0.003), L3 aBMD (r=0.18, P=0.04) and L3 width (r=0.24, P=0.006). The study suggests that exercise in pre-pubertal boys influences the accrual of bone mineral and bone width and that a 1-year school-based exercise program confers skeletal benefits, at least in the lumbar spine.

The results indicate a higher rate of overuse injuries in low back/pelvic region and shoulders than in comparable studies.

This 8-year controlled, follow-up study in 66 Swedish soccer women evaluated the effect of training and reduced training on BMD. The players who retired during the follow-up lost BMD in the femoral neck, whereas the controls did not.Introduction: Physical activity during adolescence increases BMD, but whether the benefits are retained with reduced activity is controversial. Materials and Methods: At baseline, DXA evaluated BMD in 48 active female soccer players with a mean age of 18.2 ± 4.4 (SD) years, in 18 former female soccer players with a mean age of 43.2 ± 6.2 years and retired for a mean of 9.4 ± 5.3 years, and in 64 age-and sex-matched controls. The soccer women were remeasured after a mean of 8.0 ± 0.3 years, when 35 of the players active at baseline had been retired for a mean of 5.3 ± 1.6 years. Results and Conclusions:The players still active at follow-up had a higher BMD at baseline than the matched controls in the femoral neck (FN; 1.13 ± 0.19 versus 1.00 ± 0.13 g/cm