fatigue
BRUCE
The maximum oxygen consumption and exercise performance of the subjects were evaluated using a treadmill (Pulsar, h/p/cosmos) and an automatic breathing analyzer (Vmax 29c, Sensor Medics). A polar heart rate device was used to monitor the heart rate (HR). According to Bruce's protocol, the treadmill speed started at 7.2 km/h and was increased by 1.8 km/h every 2 min until subjects experienced fatigue (Bruce et al., 