Circulating sclerostin is not suppressed following a single bout of exercise in young men

The aim of this study was to determine whether an acute bout of exercise reduces serum sclerostin under diet‐controlled conditions that stabilize the parathyroid hormone (PTH)‐1,alpha‐hydroxylase axis. Fourteen male volunteers (age, 22.1 years ± 4.05; BMI, 27.3 kg/m(2) ± 3.8) completed a randomized crossover study in which they performed 10 sets of 10 repetitions of plyometric jumps at 40% of their estimated one‐repetition maximum leg press or a nonexercise control period. A calcium‐controlled diet (1000 mg/day) was implemented prior to, and throughout each study period. Blood was drawn for analysis of serum sclerostin, Dickkopf‐1, markers of bone metabolism (PTH, calcium), markers of bone formation (bone alkaline phosphatase, BAP; osteocalcin, OCN), and markers of bone resorption (tartrate‐resistant acid phosphatase 5b, TRAP5b; C‐telopeptide cross‐links of type I collagen, CTX) at baseline and 12, 24, 48, and 72 h following exercise or rest. Changes in serum concentrations were expressed as percentage change from individual baselines. Data were analyzed using a repeated measured linear mixed model to assess effects of time, physical activity status (rest or exercise condition), and the time by activity status interaction. There was a significant effect of exercise on OCN (P = 0.005) and a significant interaction effect for CTX (P = 0.001). There was no effect of exercise on any other biochemical marker of bone metabolism. A single bout of plyometric exercise did not induce demonstrable changes in biochemical markers of bone metabolism under conditions where dietary effects on PTH were controlled.