Thepurpose of this study was to determine theeffects of intensifiedphysicaleducationsessions on adolescents ages 11-16years. Theyweredividedintotwoexperimentalgroups-high-intensity runninggroup(HIRG) and high-intensityjumpinggroup (HIJG)-and a controlgroup(C).During thesessions, heartrate(HR) wasmonitored. There wasnosignificantdifference between meanHRfor HIRG and HIJG, whilethemeanHR wassignificantlylowerfor C(p < .001). ForbothHIRG and HIJG, the mean H R was significantly higherfor girls than for bays (p < .001). Our results suggested that these intensified physical educationlessons require a highpercentage ofmaximal HR in adolescents and can beusedtoimproveaerobicfitness