Treadmill - 15% incline @ 10 mph

This activity burns approximately 1,743 calories per hour

Some of the fittest runners include indoor running sessions on a treadmill in their running programs as an effective way to improve aerobic and muscular fitness. Once or twice a week, try bringing your workout inside onto a treadmill. After leveling off at a 10-mph pace, add a 1 to 2% elevation every 5 minutes until you've reached a 15% grade.