Skeletal muscle buffering capacity and endurance performance after high-intensity interval training by well-trained cyclists

  • Adèle R. Weston
  • K. H. Myburgh
  • F. H. Lindsay
  • Steven C. Dennis
  • Timothy D. Noakes
  • J. A. Hawley

Abstract

Skeletal muscle buffering capacity (βm), enzyme activities and exercise performance were measured before and after 4 weeks of high-intensity, sub maximal␣interval training (HIT) undertaken by six well-trained competitive cyclists [mean maximal oxygen consumption (\(\)O2max) = 66.2 ml · kg−1 · min−1]. HIT replaced a portion of habitual endurance training and consisted of six sessions, each of six to eight repetitions of 5 min duration at 80% of peak sustained power output (PPO) separated by 1 min of recovery. βm increased from 206.6 (17.9) to 240.4 (34.1) μmol H+ · g muscle dw−1 · pH−1 after HIT (P = 0.05). PPO, time to fatigue at 150% PPO (TF150) and 40-km cycle time trial performance (TT40) all significantly improved after HIT (P < 0.05). In contrast, there was no change in the activity of either phosphofructokinase or citrate synthase. In addition, βm correlated significantly with TT40 performance before HIT (r = −0.82, P < 0.05) and the relationship between change in βm and change in TT40 was close to significance (r = −0.74). βm did not correlate with TF150. These results indicate that βm may be an important determinant of relatively short-duration (< 60 min) endurance cycling activity and responds positively to just six sessions of high-intensity, submaximal interval training.

Key words Buffering   Enzymes   Exercise    Training  Cycling 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Adèle R. Weston
    • 1
  • K. H. Myburgh
    • 1
  • F. H. Lindsay
    • 1
  • Steven C. Dennis
    • 1
  • Timothy D. Noakes
    • 1
  • J. A. Hawley
    • 1
  1. 1.MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, UCT Medical School, Observatory, 7925, South AfricaZA
  2. 2.Department of Physiology, Faculty of Medicine, University of Natal, Private Bag 7, Congella 4013, Durban, South AfricaZA

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