To examine whether fluctuations in training load during an Olympic year lead to changes in bone mineral densities and factors that regulate bone (sclerostin, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand), energy metabolism (insulin-like growth factor-1 and leptin), and inflammation (tumor necrosis factor-α and interleukin 6) in elite heavyweight female rowers.Methods
Blood samples were drawn from 15 female heavyweight rowers (27.0 ± 0.8 yr, 80.9 ± 1.3 kg, 179.4 ± 1.4 cm) at baseline (T1—45 wk before Olympic Games) and after 7, 9, 20, 25, and 42 wk (T1–6, respectively). Ongoing nutritional counseling was provided. Total weekly training load was recorded over the week before each time point. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry at T1 and T6.Results
Total BMD increased significantly before to after training (+0.02 g·cm−2), but was below the least significant change (±0.04 g·cm−2). Osteoprotegerin, insulin-like growth factor-1, and leptin remained stable across all time points. Fluctuations in training load (high vs low) were accompanied by parallel changes in tumor necrosis factor-α (2.1 ± 0.2 vs 1.5 ± 0.2 pg·mL−1), interleukin 6 (1.2 ± 0.08 vs 0.8 ± 0.09 pg·mL−1), and sclerostin (high: 993 ± 109 vs low: 741 ± 104 pg·mL−1).Conclusions
In this population of young female athletes with suitable energy availability, sclerostin and inflammation markers responded to fluctuations in training load, whereas BMD and bone mineral content were stable during the season, suggesting that training load periodization is not harmful for the bone health in athletes.