Purpose: This study was designed as a proof-of-concept study to assess the osteogenic index (OI) and changes in bone markers during an 8-wk jump training program. On the basis of the OI, jumps were completed in one or two daily sessions with total jumps per day being equal.
Methods: Seven males served as controls and participated in their normal strength training program. Fourteen males were divided into two groups, jumping once daily (J1×) or jumping twice daily (J2×), with a 6-h recovery period between sessions (J2× only). Jumping-type exercises were performed on a Plyo Press and started at 20 plyo-jumps per day, three times per week and progressed to 60 plyo-jumps per day, three times per week for the last 3 wk. Blood samples were collected at baseline and at 4 and 8 wk to determine serum concentrations of bone-specific alkaline phosphate and C-terminal telopeptides of type I collagen.
Results: OI for each session and week were different (P < 0.05) between the two jumping groups (baseline OI per week, J1× = 28 ± 0.9, J2× = 34 ± 0.9). There was a significant change (P = 0.005) in bone-specific alkaline phosphate over time, with 8-wk values being significantly higher than baseline values (change from baseline: J1× = 2.7 ± 1.4 μg·L−1, J2× = 3.5 ± 1.3 μg·L−1). J2× had an overall mean change significantly different from zero. C-terminal telopeptides of type I collagen did not change significantly during the 8 wk.
Conclusions: The data demonstrate that the bone of young adult males does respond to a high-impact exercise. In addition, compared with completing all plyo-jumps in one session, the use of recovery periods between exercise sessions on the same day may result in positive changes in bone turnover, indicative of an osteogenic effect. The beneficial impact of the OI and how it can be used to design programs to influence bone turnover still remain to be determined.