Bone formation is increased to a greater extent than bone resorption during a cycling stage race.

This study examined the effects of participation in the Tour of Southland, a 6-day bicycle race, on serum markers of bone turnover in 5 elite male cyclists. During the race, energy intake matched expenditure. Osteocalcin was increased approximately 300% on days 1-5; and C-terminal telopeptide of type I collagen was elevated (43%) on day 3. Participation in a cycling stage race does not appear to have deleterious effects on bone turnover.