title: Muscle cellular properties in the ice hockey player: a model for investigating overtraining?
abstract: In this study, we hypothesized that athletes involved in 5-6 months of sprint-type training would display higher levels of proteins and processes involved in muscle energy supply and utilization. Tissue was sampled from the vastus lateralis of 13 elite ice hockey players (peak oxygen consumption = 51.8 ± 1.3 mL·kg(-1)·min(-1); mean ± standard error) at the end of a season (POST) and compared with samples from 8 controls (peak oxygen consumption = 45.5 ± 1.4 mL·kg(-1)·min(-1)) (CON). Compared with CON, higher activities were observed in POST (p < 0.05) only for succinic dehydrogenase (3.32 ± 0.16 mol·(mg protein)(-1)·min(-1) vs. 4.10 ± 0.11 mol·(mg protein)(-1)·min(-1)) and hexokinase (0.73 ± 0.05 mol·(mg protein)(-1)·min(-1) vs. 0.90 ± 0.05mol·(mg protein)(-1)·min(-1)) but not for phosphorylase, phosphofructokinase, and creatine phosphokinase. No differences were found in Na(+),K(+)-ATPase concentration (β(max): 262 ± 36 pmol·(g wet weight)(-1) vs. 275 ± 27 pmol·(g wet weight)(-1)) and the maximal activity of the sarcoplasmic reticulum Ca(2+)-ATPase (98.1 ± 6.1 µmol·(g protein)(-1)·min(-1) vs. 102 ± 3.3 µmol·(g protein)(-1)·min(-1)). Cross-sectional area was lower (p < 0.05) in POST but only for the type IIA fibres (6312 ± 684 μm(2) vs. 5512 ± 335 μm(2)), while the number of capillary counts per fibre and the capillary to fibre area ratio were generally higher (p < 0.05). These findings suggest that elite trained ice hockey players display elevations only in support of glucose-based aerobic metabolism that occur in the absence of alterations in excitation-contraction processes.
authors.affiliation: Department of Kinesiology, University of Waterloo, ON, Canada. green@healthy.uwaterloo.ca
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Green
authors.forename: Aziz
authors.initials: A
authors.lastname: Batada
authors.forename: Bill
authors.initials: B
authors.lastname: Cole
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Burnett
authors.forename: Helen
authors.initials: H
authors.lastname: Kollias
authors.forename: Scott
authors.initials: S
authors.lastname: McKay
authors.forename: Brian
authors.initials: B
authors.lastname: Roy
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Schertzer
authors.forename: Ian C
authors.initials: IC
authors.lastname: Smith
authors.forename: Susan
authors.initials: S
authors.lastname: Tupling
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000378:metabolism* / Q000473:pathology*; D003402:Creatine Kinase / Q000378:metabolism; D012090:Cumulative Trauma Disorders / Q000378:metabolism* / Q000473:pathology*; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism; D006688:Hockey; D006801:Humans; D009142:Musculoskeletal Physiological Phenomena; D010101:Oxygen Consumption / Q000502:physiology; D025221:Phosphofructokinases / Q000378:metabolism; D006005:Phosphorylases / Q000378:metabolism; D052097:Quadriceps Muscle / Q000378:metabolism / Q000502:physiology; D012519:Sarcoplasmic Reticulum / Q000378:metabolism* / Q000473:pathology*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013663:Teaching / Q000379:methods; D055815:Young Adult
chemical_list: D013385:Succinate Dehydrogenase; D006005:Phosphorylases; D025221:Phosphofructokinases; D006593:Hexokinase; D003402:Creatine Kinase; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D005947:Glucose