ORIGINAL ARTICLE  BODY COMPOSITION, NUTRITION AND SUPPLEMENTATION 

The Journal of Sports Medicine and Physical Fitness 2019 October;59(10):1709-15

DOI: 10.23736/S0022-4707.19.09564-1

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English

The effects of a 226-km ironman triathlon race on bone turnover in amateur male triathletes

Chia-Ching WU ¹, Tsang-Hai HUANG ² ✉

¹ Office of Physical Education, National Taipei University, Taipei, Taiwan; ² Institute of Physical Education, Health and Leisure Studies, National Cheng Kung University, Tainan, Taiwan

BACKGROUND: The purpose of this study was to investigate the effects of an Ironman-distance triathlon on bone metabolism.
METHODS: Nine recreational male triathletes (39.7±8.2 years old) were voluntarily recruited before a 226-km Ironman triathlon race. Baseline blood samples were collected >1 hour before race. Serial post-race blood sampling time points included immediately (0hr), 1 hour (1hr), 1 day (d), 3 d, and 5 d after the Ironman race.
RESULTS: Serum muscle damage markers, serum myoglobin, creatine kinase (CK) and lactate dehydrogenase (LDH) revealed significant post-race peak values immediately, 1hr and 1d after the race, respectively. Except for the marginally higher serum CK and myoglobin at 5d (P=0.01~0.05), all post-race serum levels of muscle damage markers were significantly higher than baseline levels (P<0.01). Serum phosphorus values were significantly higher immediately (0hr) after the Ironman race. Serum osteocalcin, an index specific to bone formation, showed a significant decrease at time points 0hr and 1hr, but a significant increase 1 day after (P<0.01) and a marginal increase 3 and 5 days after (P=0.01~0.05) the race. No difference was shown in type I collagen C-telopeptide (CTX-1), a bone resorption marker. Pearson’s correlation between serum osteocalcin and CTX-1 was done at each time point, and significant correlation was shown on the 5th d after the race (r=0.591, P<0.05).
CONCLUSIONS: An Ironman-distance contest induces a bone-formative-favoring turnover during the post-race period for amateur male triathletes.

KEY WORDS: Exercise tolerance; Bone and bones; Metabolism; Bone remodeling