title: Effects of creatine supplementation and exercise training on fitness in men 55-75 yr old.
abstract: effect of oral creatine supplementation (CR; 5 g/day) in conjunction with exercise training on physical fitness was investigated in men between 55 and 75 yr of age (n = 46). A double-blind randomized placebo-controlled (PL) trial was performed over a 6-mo period. Furthermore, a subgroup (n = 20) completed a 1-yr follow-up. The training program consisted of cardiorespiratory endurance training as well as moderate resistance training (2-3 sessions/wk). Endurance capacity was evaluated during a maximal incremental bicycle ergometer test, maximal isometric strength of the knee-extensor muscles was assessed by an isokinetic dynamometer, and body composition was assessed by hydrostatic weighing. Furthermore, in a subgroup (PL: n = 13; CR: n = 12) biopsies were taken from m. vastus lateralis to determine total creatine (TCr) content. In PL, 6 mo of training increased peak oxygen uptake rate (+16%; P < 0.05). Fat-free mass slightly increased (+0.3 kg; P < 0.05), whereas percent body fat slightly decreased (-1.2%; P < 0.05). The training intervention did not significantly change either maximal isometric strength or body weight. The responses were independent of CR. Still, compared with PL, TCr was increased by approximately 5% in CR, and this increase was closely correlated with initial muscle creatine content (r = -0.78; P < 0.05). After a 1-yr follow-up, muscle TCr was not higher in CR than in PL. Furthermore, the other measurements were not affected by CR. It is concluded that long-term creatine intake (5 g/day) in conjunction with exercise training does not beneficially impact physical fitness in men between 55 and 75 yr of age.
authors.affiliation: Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, KU Leuvrn, B-3001 Leuven, Belgium.
authors.forename: Bert O
authors.initials: BO
authors.lastname: Eijnde
authors.forename: Marc
authors.initials: M
authors.lastname: Van Leemputte
authors.forename: Marina
authors.initials: M
authors.lastname: Goris
authors.forename: Valery
authors.initials: V
authors.lastname: Labarque
authors.forename: Youri
authors.initials: Y
authors.lastname: Taes
authors.forename: Patricia
authors.initials: P
authors.lastname: Verbessem
authors.forename: Luc
authors.initials: L
authors.lastname: Vanhees
authors.forename: Monique
authors.initials: M
authors.lastname: Ramaekers
authors.forename: Bart
authors.initials: B
authors.lastname: Vanden Eynde
authors.forename: Reinout
authors.initials: R
authors.lastname: Van Schuylenbergh
authors.forename: Rene
authors.initials: R
authors.lastname: Dom
authors.forename: Erik A
authors.initials: EA
authors.lastname: Richter
authors.forename: Peter
authors.initials: P
authors.lastname: Hespel
mesh_terms: D000284:Administration, Oral; D000368:Aged; D001823:Body Composition; D003401:Creatine / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism / Q000652:urine; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test; D005500:Follow-Up Studies; D006651:Histocytochemistry; D006801:Humans; D007537:Isometric Contraction; D007717:Knee; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D010101:Oxygen Consumption; D010806:Physical Education and Training; D010807:Physical Endurance; D010809:Physical Fitness; D013997:Time Factors; D014891:Weight Lifting
chemical_list: D003401:Creatine