Objective: The skeleton has been suggested to be involved in energy metabolism through osteocalcin (OC), an osteoblast-specific molecule. The objective of this study was to investigate whether high-impact (HI) exercise stimulating bone formation would lead to changes in glucose and lipid metabolism independent of cardiorespiratory effects and whether OC mediates this association.
Design: Prospective intervention study.
Methods: Fifty men aged 20-32 years were allocated to an intervention group or a control group. The intervention group completed six different types of jumps in sets of five, with the frequency of these exercises gradually increasing over 8 weeks. At baseline and after 8 weeks, glycerol concentrations were measured in fat tissue as a marker of lipolysis using microdialysis. Blood samples were assayed for OC and markers of glucose and lipid metabolism. Physical activity was measured using an accelerometer.
Results: After adjustment for confounders at baseline and changes in physical activity during the intervention period, the intervention was associated with a decrease in levels of glucose (P = 0·04), adrenalin (P = 0·03) and OC (P = 0·04) after adjusting for baseline levels and changes in physical activity. No other differences between the groups were significant, although the trends of the metabolic variables favoured the intervention group.
Conclusions: The results of this study suggest that HI loading on the skeleton may affect glucose metabolism independent of the level of aerobic exercise.
© 2012 Blackwell Publishing Ltd.