Direct effects of physical training on markers of bone metabolism and serum sclerostin concentrations in older adults with low bone mass

Background: Both gravitational loading and the forces generated by muscle contraction have direct effects on serum markers of bone metabolism. The object of this study was to examine the direct effects of a single session of resistance exercise or walking on biochemical markers of bone metabolism in participants with low bone mass. Methods: A total of 150 otherwise healthy female subjects (mean age = 59.1 +/- 7.1 years) diagnosed with osteoporosis or osteopenia were randomly allocated to either a resistance exercise group (RG; n = 50), walking group (WG; n = 50), or control group (CG; n = 50). Changes in bone-specific alkaline phosphatase (BALP), carboxy-terminal cross-linked telopeptide of type I collagen (CTX), and serum sclerostin concentrations were measured before and immediately after a single exercise intervention. Results: There was no significant change in BALP values in any of the groups. Sclerostin levels increased in the RG and WG, and there was significant difference between the WG and CG after the exercise intervention (P < 0.01). In contrast, the changes in CTX concentrations from baseline were significant in the RG (P < 0.01) but not in the WG (P = 0.11), and there was a significant difference between resistance exercise and walking (P < 0.01). Conclusions: In participants with low bone mass, resistance exercise influenced the serum concentrations of CTX, a marker of bone resorption, but walking did not.