So, I've used a few different activity/diet tracking applications to monitor calories in/calories out. I'm always put off by the numbers they come up with for tennis as an exercise. From Myfitnesspal.com: 60 minutes of tennis singles amounts to 840 calories burned. 60 minutes of doubles tennis: 525 calories. By comparison, 60 minutes of jogging (6mph): 1680 calories. It's as if they are saying 60 minutes of singles doesn't consider all the breaks between points, change overs, etc. If I were to just hit for 60 minutes in a row, I could see an expenditure of something like that, but playing a 2 hour match should have me depleted if I'm working through 1680 calories. What do you think is a 'realistic' number of calories burned during a couple sets? Or, should I go ahead and take credit for the 840 cal/hour?