Bone turnover following high-impact exercise is not modulated by collagen supplementation in young men: A randomized cross-over trial

Introduction: We assessed whether collagen supplementation augments the effects of high-impact exercise on bone turnover and whether a higher exercise frequency results in a greater benefit for bone metabolism. Methods: In this randomized, cross-over trial, 14 healthy males (age 24 +/- 4 y, BMI 22.0 +/- 2.1 kg/m2) performed 5-min of high-impact exercise once (JUMP+PLA and JUMP+COL) or twice daily (JUMP2+COL2) during a 3-day intervention period, separated by a 10-day wash out period. One hour before every exercise bout participants ingested 20 g hydrolysed collagen (JUMP+COL and JUMP2+COL2) or a placebo control (JUMP+PLA). Blood markers of bone formation (P1NP) and resorption (CTX-I) were assessed in the fasted state before the ingestion of the initial test drinks and 24, 48, and 72 h thereafter. In JUMP+PLA and JUMP+COL, additional blood samples were collected in the postprandial state at 1, 2, 3, 4, 5 and 13 h after ingestion of the test drink. Results: In the postprandial state, serum P1NP concentrations decreased marginally from 99 +/- 37 to 93 +/- 33 ng/ mL in JUMP+COL, and from 97 +/- 32 to 92 +/- 31 ng/mL in JUMP+PLA, with P1NP levels having returned to baseline levels after 13 h (time-effect, P = 0.053). No differences in serum P1NP concentrations were observed between JUMP+PLA and JUMP+COL (time x treatment, P = 0.58). Serum CTX-I concentrations showed a - 50 % decline (time, P < 0.001) in the postprandial state in JUMP+COL (0.9 +/- 0.3 to 0.4 +/- 0.2 ng/mL) and JUMP+PLA (0.9 +/- 0.3 to 0.4 +/- 0.2 ng/mL), with no differences between treatments (time x treatment, P = 0.17). Fasted serum P1NP concentrations increased -8 % by daily jumping exercise (time-effect, P < 0.01), with no differences between treatments (time x treatment, P = 0.71). Fasted serum CTX-I concentrations did not change over time (time-effect, P = 0.41) and did not differ between treatments (time x treatment, P = 0.58). Conclusions: Five minutes of high-impact exercise performed daily stimulates bone formation during a 3-day intervention period. This was indicated by an increase in fasted serum P1NP concentrations, rather than an acute increase in post-exercise serum P1NP concentrations. Collagen supplementation or an increase in exercise frequency does not further increase serum P1NP concentrations. The bone resorption marker CTX-I was not affected by daily short-duration high-impact exercise with or without concurrent collagen supplementation.