Running vs Sprinting

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Just wondering if anyone knows if you burn more calories sprinting than you do running? I've been sprinting this week, one minute on and one minute off, and I think it is physically more difficult than running straight through. MFP doesn't have sprinting in their lists of exercises, so I'm wondering if anyone knows if you burn more calories sprinting than running? I'm sprinting at 8mph and walking at 4 mph. Thanks!