SHORTER RATHER THAN LONGER WORK INTERVALS FACILITATE MORE WORK VOLUME

Rozenek, R., Funato, K., Junjiro, K., Hoshikawa, M., & Matsuno, A. (2003). Physiological responses to interval training at velocities associated with VO2max. Medicine and Science in Sports and Exercise, 35(5), Supplement abstract 493.

This study attempted to characterize the physiological responses associated with performing at 100% VO2max. Male Ss (N = 12) participated in three trials of treadmill running under the following conditions: 15 s of work, 15 s of recovery; 30 s of work, 15 s of recovery; and 60 s of work, 15 s of recovery. Work was performed at 100% VO2max and recovery was performed at 50% VO2max. The total distance covered in work was intended to be 2400 m. A fourth trial was performed continuously at 100% VO2max.

All Ss completed the 15:15 and 30:15 trials. Only five completed the 60:15 trials. Percent VO2max was lowest in the 15:15 trials. Percent VO2max was similar in the 60:15 and continuous running trials. VO2max for the 30:15 trials fell in between the values of the 15:15 and 60:15 trials. Similar relationships were recorded for perceived exertion values and heart rates. Blood lactate values following the exercises were lowest for the 15:15 condition and similar for the three other conditions.

Implication. The 30:15 condition appeared to stimulate both aerobic (VO2max) and anaerobic (high lactate at finish) mechanisms. The 15:15 condition stimulated aerobic adaptation with much less anaerobic stimulation. More work could have been achieved under the 15:15 condition.

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