Enter your threshold heart rate to calculate your heart rate based training zones: - Recovery - Aerobic(All day pace) - Tempo(2.5 to 8 hours) - Sub-Threshold(10 to 60 minutes) - Super-Threshold(3 to 8 minutes) - Aerobic Capacity(30 seconds to 3 minutes) - Anaerobic Capacity(5 to 30 seconds) Features: - Calculate heart rate training zones based off your threshold heart rate - 7 Training zones - Joe Friel training zones - Free to use Good for road cycling, triathlon, mountain biking, running and