title: Bone turnover responses to changed physical activity.
abstract: The aim of the study was to compare bone turnover in male soccer players with controls and to follow bone turnover with changes in activity level. Serum-osteocalcin (OC), carboxy-terminal propeptide of type I collagen (PICP) and total alkaline phosphatases (tALP) were measured to assess bone formation. Bone resorption was detected by carboxyterminal cross-linked telopeptide of type I collagen (ICTP). Bone turnover of 12 male premier league soccer players (mean age 23 years, range, 17-34) exercising 12 hours/week (range, 8-15) were at the last day of the soccer season compared with 27 age- and gender-matched controls. Bone turnover was followed weekly during a 4-week resting period between two seasons, and a further 10 days following resumption of full training. Data are presented as mean +/- SEM. Both OC (22 +/- 12%) and ICTP (34 +/- 17%) were higher in the players compared with the controls at the end of the season (both P < 0.05, respectively). After 2 weeks of reduced physical activity among the athletes, the PICP levels were 21 +/- 4% (P < 0.05) lower and the ICTP levels 8 +/- 12% higher (P = 0.07) compared with baseline. OC, PICP, and tALP was then no different compared with controls and ICTP was higher than controls (P < 0.001). Ten days within the new season, there was a 23 +/- 5% increase in PICP (P < 0.001) and a 4 +/- 4% decrease in ICTP (P < 0.05) compared with the end of the resting period. In summary, male soccer players have higher bone turnover compared with age- and gender-matched controls. Changes in physical activity level were associated with changes in bone formation and resorption as evaluated by bone markers within weeks, and after 2 weeks rest, ICTP was higher in the athletes than the controls. We conclude that the higher age-related diminution in BMD, previously reported in former soccer players compared with age- and gender-matched controls, may be the result of increased bone resorption, evaluated by ICTP, compared with the controls.
authors.affiliation: Department of Orthopaedics, Malmo University Hospital, Malmo, Sweden. magnus.karlsson@orto.mas.lu.se
authors.forename: K M
authors.initials: KM
authors.lastname: Karlsson
authors.forename: C
authors.initials: C
authors.lastname: Karlsson
authors.forename: H G
authors.initials: HG
authors.lastname: Ahlborg
authors.forename: O
authors.initials: O
authors.lastname: Valdimarsson
authors.forename: S
authors.initials: S
authors.lastname: Ljunghall
authors.forename: K J
authors.initials: KJ
authors.lastname: Obrant
mesh_terms: D000293:Adolescent; D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D016723:Bone Remodeling / Q000502:physiology*; D024042:Collagen Type I; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D010455:Peptides; D011347:Procollagen / Q000097:blood; D012146:Rest / Q000502:physiology*
chemical_list: D024042:Collagen Type I; D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen; C052929:collagen type I trimeric cross-linked peptide; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; D000469:Alkaline Phosphatase