Effects of creatine supplementation and exercise training on fitness in men 55-75 yr old.
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.
Eijnde
Bert O
BO
Exercise Physiology and Biomechanics Laboratory, Faculty of Physical Education and Physiotherapy, KU Leuvrn, B-3001 Leuven, Belgium.
Van Leemputte
Marc
M
Goris
Marina
M
Labarque
Valery
V
Taes
Youri
Y
Verbessem
Patricia
P
Vanhees
Luc
L
Ramaekers
Monique
M
Vanden Eynde
Bart
B
Van Schuylenbergh
Reinout
R
Dom
Rene
R
Richter
Erik A
EA
Hespel
Peter
P
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
D003401:Creatine