title: Competitive season of triathlon does not alter bone metabolism and bone mineral status in male triathletes.
abstract: This longitudinal study evaluated the effects of a triathlon season on bone metabolism and hormonal status. Seven male competitive triathletes (mean age 19.3 years, range 18 - 20) with 5.0 +/- 0.3 years of competition experience were tested twice during the season: at the beginning of training and 32 weeks later. Total and regional bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry, while bone turnover was evaluated by specific biochemical markers: bone-specific alkaline phosphatase (B-ALP), osteocalcin, and urinary type I collagen C-telopeptide. In addition, sexual, calciotropic and somatotropic hormones were also analyzed. After 32 weeks, a BMD increase was found at the lumbar spine (1.9 %; p = 0.031) and skull (3.1 %; p = 0.048), while no variation was observed for total body or at the proximal femur. The B-ALP level decreased (-23.2 %; p = 0.031), but no variation was found for the other bone markers. 1.25 (OH) (2)D3, IGF-1 and the bioavailability IGF-1 index (IGF-1/IGFBP-3) increased by 18.3 % (p = 0.047), 29 % (p = 0.048), 33 % (p = 0.011), respectively, while PTH, testosterone, IGFBP-3 and cortisol concentrations were unchanged. In conclusion, the triathlon season had a moderately favourable effect on BMD, although a slowing down of bone formation activity was observed. No variation in hormonal levels was observed that could have limited the effects of exercise on bone tissue.
authors.affiliation: Groupe de Recherche Interdisciplinaire Sur le Métabolisme Osseux (GRISMO), Montpellier, France. laurent.maimoun@oreka.fr
authors.forename: L
authors.initials: L
authors.lastname: Maïmoun
authors.forename: O
authors.initials: O
authors.lastname: Galy
authors.forename: J
authors.initials: J
authors.lastname: Manetta
authors.forename: O
authors.initials: O
authors.lastname: Coste
authors.forename: E
authors.initials: E
authors.lastname: Peruchon
authors.forename: J P
authors.initials: JP
authors.lastname: Micallef
authors.forename: D
authors.initials: D
authors.lastname: Mariano-Goulart
authors.forename: I
authors.initials: I
authors.lastname: Couret
authors.forename: C
authors.initials: C
authors.lastname: Sultan
authors.forename: M
authors.initials: M
authors.lastname: Rossi
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism; D001642:Bicycling / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology; D001842:Bone and Bones / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I; D004797:Enzyme-Linked Immunosorbent Assay; D005080:Exercise Test; D006728:Hormones / Q000378:metabolism; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015675:Osteocalcin / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D012420:Running / Q000502:physiology*; D018709:Statistics, Nonparametric; D013550:Swimming / Q000502:physiology*
chemical_list: D024042:Collagen Type I; D006728:Hormones; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D003094:Collagen; D000469:Alkaline Phosphatase