To evaluate the magnitude of the stress on the aerobic and the anaerobic energy release systems during high intensity bicycle training, two commonly used protocols (IE1 and IE2) were examined during bicycling. IE1 consisted of one set of 6-7 bouts of 20-s exercise at an intensity of approximately 170% of the subject's maximal oxygen uptake (˙VO2max) with a 10-s rest between each bout. IE2 involved one set of 4-5 bouts of 30-s exercise at an intensity of approximately 200% of the subject's ˙VO2max and a 2-min rest between each bout. The accumulated oxygen deficit of IE1 (69± 8 ml·kg-1, mean ± SD) was significantly higher than that of IE2 (46 ± 12 ml·kg-1, N = 9, p< 0.01). The accumulated oxygen deficit of IE1 was not significantly different from the maximal accumulated oxygen deficit (the anaerobic capacity) of the subjects (69 ± 10 ml·kg-1), whereas the corresponding value for IE2 was less than the subjects' maximal accumulated oxygen deficit (P < 0.01). The peak oxygen uptake during the last 10 s of the IE1 (55 ± 6 ml·kg-1·min-1) was not significantly less than the ˙VO2max of the subjects (57± 6 ml·kg-1·min-1). The peak oxygen uptake during the last 10 s of IE2 (47 ± 8 ml·kg-1·min-1) was lower than the˙VO2max (P < 0.01). In conclusion, this study showed that intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally.
Department of Physiology and Biomechanics, National Institute of Fitness and Sports, Kanoya City, Kagoshima Prefecture, 891-23 JAPAN; and The Japanese National Speed Skating Team, National Skating Union of Japan, Kishi Memorial Hall, Shibuya City, Tokyo 150, JAPAN
Submitted for publication January 1996.
Accepted for publication September 1996.
The authors appreciated stimulating discussions with Dr. Mitsumasa Miyashita (University of Tokyo) and the generous help of Ms. Donna Gardecki and Mr. Raymond Fujino in editing the English manuscript.
Address for all correspondence: I. Tabata, Ph.D., Laboratory of Exercise Physiology, Division of Health Promotion, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku City, Tokyo 162, Japan. E-mail:firstname.lastname@example.org.
Present address for K. Nishimura: General Research and Development Section, Product Development Department, Moon-Star Chemical Corporation, Kurume City, Fukuoka Prefecture, 830-91 Japan.
Present address for M. Kouzaki: Graduate School, University of Tokyo, 3-8-1 Komaba, Meguro City, Tokyo, 153 Japan.
Present address for M. Miyachi: Department of Health and Sports Sciences, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki City, Okayama Prefecture, 701-01 Japan.