This study investigated the relationship of high-power work capacity with physiological variables during supramaximal intermittent exercise and individually measured alactic (ATP-CP), lactic (LA), and oxygen (O₂) energy delivery systems. Nineteen university handball players (experiment 1) and 23 university basketball players (experiment 2) performed an intermittent exercise routine consisting of a combination of high-power and low-power exercise. The exercise protocols were a laboratory test consisting of pedaling on a bicycle ergometer (experiment 1) and a field test consisting of a running protocol incorporating changes in direction (experiment 2) . The main results were as follows :
(1) The ATP-CP system was significantly related to power output during the early stage of intermittent exercise and the O₂ system was significantly related to power output in the middle and late stages of intermittent exercise. As an indicator of the O2 system, blood lactate concentration during submaximal exercise correlated more closely with power output during intermittent exercise compared with VO₂max/BW. The LA system was not significantly related to power output during intermittent exercise.
(2) Subjects were divided into 2 groups according to energy delivery ability and then power output ability during intermittent exercise was compared. The high ATP-CP system group had a significantly higher power output during the early stage of intermittent exercise compared with the low ATP-CP system group. The high O₂ system group had a significantly higher power output in the middle and late stages of intermittent exercise compared with the low O₂ system group. Compared to the low O₂ system group, the high O₂ system group had a higher absolute VO₂ during the low intensity active recovery periods of intermittent exercise, as well as a tendency to have lower blood lactate levels. The high LA system group showed lower power output over the course of intermittent exercise compared with the low LA system group.
These results indicate that the O₂ system is important for exerting higher power output during supramaximal intermittent exercise.