Muscle metabolism during fatiguing isometric quadriceps exercise in adolescents and adults

作者：Willcocks Rebecca J; Fulford Jonathan; Armstrong Neil; Barker Alan R; Williams Craig A^*

来源：Applied Physiology Nutrition and Metabolism, 2014, 39(4): 439-445.

DOI：10.1139/apnm-2013-0192

• acidosis
• inorganic phosphate
• pediatric exercise physiology
• 31-phosphorus magnetic resonance spectroscopy
• anaerobic metabolism
• quadriceps

Children and adolescents are less susceptible to muscle fatigue during repeated bouts of high-intensity exercise than adults, but the physiological basis for these differences is not clear. The purpose of the current investigation was to investigate the muscle metabolic responses, using 31-phosphorus magnetic resonance spectroscopy, during fatiguing isometric quadriceps exercise in 13 adolescents (7 females) and 14 adults (8 females). Participants completed 30 maximal voluntary contractions (6-s duration) separated by 6 s of rest. Fatigue was quantified as the relative decrease in force over the test. Fatigue was not significantly different with age (p = 0.20) or sex (p = 0.63). Metabolic perturbation (change in phosphocreatine, inorganic phosphate, and ADP concentrations) was significantly greater in adults compared with adolescents; no sex effects were present. Muscle pH did not differ with age or sex. Phosphocreatine recovery following exercise was not significantly different with age (p = 0.27) or sex (p = 0.97) but a significant interaction effect was present (p = 0.04). Recovery tended to be faster in boys than men but slower in girls than women, though no significant group differences were identified. The results of this study show that at a comparable level of muscle fatigue, the metabolic profile is profoundly different between adolescents and adults.

• 出版日期2014-4