Effects of HIIT Integrated in PE Classes, on Physical Condition, Physical Activity and Motivation for Exercise

"The program will be applied in the first 10-15 minutes of each PE class, twice a week, including a brief warm-up, ranged from 14 to 20 intervals, adopting a 2:1 work to rest ratio (ie, 30-s work, followed by 30-s rest)~A cut-point of \>=90% of maximal heart rate was used as our criterion for satisfactory compliance to high-intensity exercise~In order to estimate effort, fatigue and training load, a subjective effort scale will be used throughout each session. The heart rate will be monitored throughout the session in real time through Bluetooth technology.~Actigraph accelerometers (wGT3X-BT), randomly distributed by the students in each session, will be used to characterize the intensity of the sessions."