Bone Response to Exercise and Energy Restriction in Young Adults

Cycling is commonly questioned whether it provides adequate mechanical strain on bone as many elite cyclists have been found to have a low bone mass. However, it remains unclear if this is due to cycling or low energy availability. In addition, acute dietary energy restriction has been found to be accompanied by an imbalance in bone remodelling with reduced bone formation. The objective of this proposal is to examine whether short-term energy restriction leads to changes in markers of bone formation and resorption at rest and in response to cycling in young adults. Specifically, the study will examine changes in circulating bone markers in 15 males and females (ages 18-24) both at rest and following one 45-minute spinning class both before and after one week of restricted energy intake. Blood will be drawn at rest (pre-trial, fasted), and 3 times post-trial (5 min, 1h and 24h); then analysed for biochemical markers of bone formation (BAP and OPG) and resorption (CTX and RANKL) to assess the impact of energy restriction on bone at rest and in response to exercise. This innovative work has potential to make significant advances in understanding tissue growth and development in response to exercise and malnutrition.