The effects of training intensity on muscle buffer capacity in females

Eur J Appl Physiol. 2006 Jan;96(1):97-105. doi: 10.1007/s00421-005-0068-6. Epub 2005 Nov 10.


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).

MeSH terms

  • Adolescent
  • Adult
  • Buffers
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / physiology*
  • Oxygen Consumption
  • Physical Fitness / physiology*
  • Pulmonary Gas Exchange


  • Buffers