PURPOSE: We previously reported that 12 months of resistance training (RT, 2x/wk, n = 19) or jump training (JUMP, 3x/wk, n = 19) increased whole body and lumbar spine BMD and increased serum bone formation markers relative to resorption in physically active (>= 4 h/wk) men (mean age 44 +/- 2 y; median 44 y) with osteopenia of the hip or spine. The purpose of this secondary analysis was to examine the effects of the RT or JUMP intervention on potential endocrine mediators of the exercise effects on bone, specifically IGF-I, PTH and sclerostin. METHODS: Fasting blood samples were collected after a 24-h period of no exercise at baseline and after 12 months of RT or JUMP. IGF-I, PTH and sclerostin were measured in serum by ELISA. The effects of RT or JUMP on IGF-I, PTH and sclerostin were evaluated using 2x2 repeated measures ANOVA (time x group). This study was conducted in accordance with the Declaration of Helsinki and was approved by the University of Missouri IRB. RESULTS: Sclerostin concentrations in serum significantly decreased and IGF-I significantly increased after 12 months of RT or JUMP; while PTH remained unchanged. CONCLUSION: The beneficial effects of long-term, progressive-intensity RT or JUMP on BMD in moderately active men with low bone mass are associated with decreased sclerostin and increased IGF-I.
With permission from Excerpta Medica Inc.

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