High-intensity exercise decreases muscle buffer capacity via a decrease in protein buffering in human skeletal muscle.
We have previously reported an acute decrease in muscle buffer capacity (betam(in vitro)) following high-intensity exercise. The aim of this study was to identify which muscle buffers are affected by acute exercise and the effects of exercise type and a training intervention on these changes. Whole muscle and non-protein betam(in vitro) were measured in male endurance athletes (VO(2max) = 59.8 +/- 5.8 mL kg(-1) min(-1)), and before and after training in male, team-sport athletes (VO(2max) = 55.6 +/- 5.5 mL kg(-1) min(-1)). Biopsies were obtained at rest and immediately after either time-to-fatigue at 120% VO(2max) (endurance athletes) or repeated sprints (team-sport athletes). High-intensity exercise was associated with a significant decrease in betam(in vitro) in endurance-trained males (146 +/- 9 to 138 +/- 7 mmol H(+) x kg d.w.(-1) x pH(-1)), and in male team-sport athletes both before (139 +/- 9 to 131 +/- 7 mmol H(+) x kg d.w.(-1) x pH(-1)) and after training (152 +/- 11 to 142 +/- 9 mmol H(+) x kg d.w.(-1) x pH(-1)). There were no acute changes in non-protein buffering capacity. There was a significant increase in betam(in vitro) following training, but this did not alter the post-exercise decrease in betam(in vitro). In conclusion, high-intensity exercise decreased betam(in vitro) independent of exercise type or an interval-training intervention; this was largely explained by a decrease in protein buffering. These findings have important implications when examining training-induced changes in betam(in vitro). Resting and post-exercise muscle samples cannot be used interchangeably to determine betam(in vitro), and researchers must ensure that post-training measurements of betam(in vitro) are not influenced by an acute decrease caused by the final training bout.
School of Human Movement and Exercise Science, The University of Western Australia, Crawley, WA, 6009, Australia. David.Bishop@univr.it
David
D
Bishop
Johann
J
Edge
Alberto
A
Mendez-Villanueva
Claire
C
Thomas
Knut
K
Schneiker
D056352:Athletes; D002021:Buffers; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D052097:Quadriceps Muscle / Q000737:chemistry / Q000502:physiology; D012420:Running / Q000502:physiology*
D002021:Buffers; D011506:Proteins