Gender modulates the energy cost of muscle contraction in untrained healthy subjects. A 31P magnetic resonance spectroscopy analysis.
The forearm flexor muscles of 56 untrained volunteers (26 women and 30 men) were examined by 31P magnetic resonance spectroscopy, during a rest-exercise-recovery protocol, in order to document the impact of gender on muscle energetics. Absolute concentrations of high-energy phosphate compounds, intracellular pH and rates of aerobic and anaerobic ATP production were calculated. An inverse correlation was found between body mass index (BMI) and power output in women but not in men. After correcting for power output and BMI, the measured energy cost of contraction was twice larger for women than for men. This increase was also reflected in larger ATP production from aerobic and anaerobic pathways. This higher energy cost might be explained in part by differences in local muscle mass, a higher impact of fatness, but also by a reduced metabolic efficiency of muscle fibers in untrained women.
Mattei
J P
JP
Centre de Résonance Magnétique Biologique et Médicale, UMR CNRS no. 6612, Faculté de Médecine de la Timone, Marseille, France.
Bendahan
D
D
Roussel
M
M
Lefur
Y
Y
Cozzone
P J
PJ
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000328:Adult; D015992:Body Mass Index; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D010084:Oxidation-Reduction; D010761:Phosphorus Radioisotopes; D012727:Sex Characteristics
D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate