Effects of high-intensity training on muscle lactate transporters and postexercise recovery of muscle lactate and hydrogen ions in women.
The purpose of this study was to investigate the effects of high-intensity interval training (3 days/wk for 5 wk), provoking large changes in muscle lactate and pH, on changes in intracellular buffer capacity (betam(in vitro)), monocarboxylate transporters (MCTs), and the decrease in muscle lactate and hydrogen ions (H+) after exercise in women. Before and after training, biopsies of the vastus lateralis were obtained at rest and immediately after and 60 s after 45 s of exercise at 190% of maximal O2 uptake. Muscle samples were analyzed for ATP, phosphocreatine (PCr), lactate, and H+; MCT1 and MCT4 relative abundance and betam(in vitro) were also determined in resting muscle only. Training provoked a large decrease in postexercise muscle pH (pH 6.81). After training, there was a significant decrease in betam(in vitro) (-11%) and no significant change in relative abundance of MCT1 (96 +/- 12%) or MCT4 (120 +/- 21%). During the 60-s recovery after exercise, training was associated with no change in the decrease in muscle lactate, a significantly smaller decrease in muscle H+, and increased PCr resynthesis. These results suggest that increases in betam(in vitro) and MCT relative abundance are not linked to the degree of muscle lactate and H+ accumulation during training. Furthermore, training that is very intense may actually lead to decreases in betam(in vitro). The smaller postexercise decrease in muscle H+ after training is a further novel finding and suggests that training that results in a decrease in H+ accumulation and an increase in PCr resynthesis can actually reduce the decrease in muscle H+ during the recovery from supramaximal exercise.
Bishop
David
D
School of Human Movement and Exercise Science, The University of Western Australia, Crawley, Western Australia, Australia. David.Bishop@univr.it
Edge
Johann
J
Thomas
Claire
C
Mercier
Jacques
J
D000255:Adenosine Triphosphate / Q000378:metabolism; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism*; D027501:Monocarboxylic Acid Transporters / Q000378:metabolism*; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000378:metabolism; D010101:Oxygen Consumption; D010725:Phosphocreatine / Q000378:metabolism; D052097:Quadriceps Muscle / Q000378:metabolism*; D020127:Recovery of Function; D055070:Resistance Training; D027981:Symporters / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult; D000099233:Monocarboxylate Transport Protein 1
D000255:Adenosine Triphosphate; D019344:Lactic Acid; D027501:Monocarboxylic Acid Transporters; D009124:Muscle Proteins; D010725:Phosphocreatine; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1; C406962:SLC16A4 protein, human