No abstract

The effects of a 9-week lower-body plyometric training program on bone mass, bone markers and physical fitness was examined in 51 early pubertal male basketball players divided randomly into a plyometric group (PG: 25 participants) and a control group (CG: 26 participants). Areal bone mineral density (aBMD), bone mineral content (BMC), and bone area (BA) in the whole body, L2-L4 vertebrae, and in total hip, serum levels of osteocalcin (Oc) and C-terminal telopeptide fragment of Type I collagen (CTx), jump, sprint and power abilities were assessed at baseline and 9 weeks. Group comparisons were done by independent student's t-test between means and analyses of (ANOVA) and covariance (ANCOVA), adjusting for baseline values. PG experienced a significant increase in Oc (p < .01) and all physical fitness except for the 5-jump test. However, there was no improvement in aBMD, BMC and BA in any measured site, except in whole body BMC of the PG. A positive correlation was observed between percentage increase (Δ%) of physical fitness and those of (Oc) for the PG. In summary, biweekly sessions of lower body plyometric training program were successful for improving whole body BMC, bone formation marker (Oc) and physical fitness in early pubertal male basketball players.

No abstract

The purpose of this study was to investigate the effect of 18 months of high and low levels of volleyball practice on bone acquisition. 130 prepubescent boys (mean age 11.4 ± 0.7) were divided into a high-level training group (HLG), low-level training group (LLG), and controls. Bone mineral content (BMC) and bone area at the whole body, lumbar spine L2-L4, femoral neck of the dominant leg, and right and left radius were measured using dual-photon X-ray absorptiometry. Enhanced BMC resulted from high-training volleyball activity in all measured sites except the third left and right distal radius, which is not modified by low-level training in prepubescent players but it was accompanied by a bone area expansion in radius and weight-bearing sites for the HLG, and in legs, whole right and left radius for the LLG. Significant improvement of skeletal tissues is associated with the intensity and duration of volleyball training.

No abstract