The effects of training intensity on muscle buffer capacity in females.
We examined changes in muscle buffer capacity (beta m(in vitro)), VO2peak and the lactate threshold (LT) after 5 weeks of high-intensity interval training (INT) above the LT or moderate-intensity continuous training (CON) just below the LT. Prior to and immediately after training, 16 female subjects performed a graded exercise test to determine VO2peak and the LT, followed 2 days later by a resting muscle biopsy from the vastus lateralis muscle to determine beta m(in vitro). Following baseline testing, the subjects were randomly placed into the INT (n=8) or CON training group (n=8). Subjects then performed 5 weeks of cycle training (3 days per week), performing either high-intensity INT (6-10x2 min at 120-140% LT with 1 min rest) or moderate-intensity CON (80-95% LT) training. Total training volume was matched between the two groups. After the training period, both groups had significant improvements in VO2peak (12-14%; P<0.05) and the LT (7-10%; P<0.05), with no significant differences between groups. The INT group, however, had significantly greater improvements in beta m(in vitro) (25%; 123+/-5-153+/-7 micromol H+ x g muscle dm(-1) x pH(-1); P<0.05) than the CON group (2%; 130+/-12-133+/-7 micromol H+ x g muscle dm(-1) x pH(-1), P>0.05). Our results show that when matched for training volume, high-intensity interval training above the LT results in similar improvements in VO2peak and the LT, but greater improvements in beta m(in vitro) than moderate-intensity continuous training below the LT. This suggests that training intensity is an important determinant of changes to beta m(in vitro).
Edge
Johann
J
Team Sport Research Group, School of Human Movement and Exercise Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Bishop
David
D
Goodman
Carmel
C
D000293:Adolescent; D000328:Adult; D002021:Buffers; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D011659:Pulmonary Gas Exchange
D002021:Buffers