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RESEARCH PRODUCT

Short term bone biochemical response to a single bout of high-impact exercise

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Rantalainen, Timo. 2006. Short term bone biochemical response to a single bout of high-impact exercise. Department of Biology of Physical Activity, University of Jyväskylä. Master thesis in Exercise Physiology. 29 pages. INTRODUCTION: Bones adapt to imposed loading environment, but the adaptive process takes years to complete. The state of skeletal turnover can be evaluated with biochemical markers of bone formation and resorption. Thus it is possible to observe the response of bone to a single bout of exercise. Currently the results concerning acute short term bone response after a single bout of loading are equivocal. Therefore, the purpose of the study was to examine the response of bone biochemical markers to a single bout of high-impact exercise. METHODS: 18 physically active young subjects volunteered to participate. The subjects performed hopping with ankle plantarflexor muscles at 65 % of maximal ground reaction force until exhaustion. Venous blood samples were drawn before (baseline), after, 2h, on day 1 and on day 2 after the exercise. Procollagen type I amino terminal propeptide (P1NP) formation marker and carboxyterminal crosslinked telopeptide (CTx) resorption marker were analyzed from the blood samples. Marker concentrations were adjusted for changes in blood plasma volume. Non-parametric Friedman and Wilcoxon tests were used for multiple comparisons of mean values and Spearman test was used for correlation analysis. RESULTS: CTx increased significantly two days after the exercise and P1NP one day after. There was a significant positive correlation (r ? 0.54, P ? 0.008) between loading variables and relative change in P1NP on day 1 DISCUSSION: Considering that only two biochemical bone turnover markers were assessed, it can be concluded that bone response to a single bout of strenuous highimpact exercise can be seen by observing the biochemical bone markers during just two days ensuing the exercise. The biochemical marker response seems to depend on exercise type even if high intensity exercises are used.