The American T'ai Chi Associates recommends looking for a school that adheres to the original principles of the martial art it offers, rather than one that dilutes them by, say, pairing jujitsu with kickboxing: The purer the teaching, the more your child stands to gain.
The mean calories burned per minute of tennis, based on the list of 5 activities, shown below, for an average male, weighing 190 pounds (86 kg) is 9 Calories per minute. The average per minute for an average female, weighing 163 pounds (74 kg) is 7 Calories per minute.
Multiply the result from Step 4 by the number of minutes you played, then divide by 200 to find out how many calories you burned. For example, if you weigh 70 kilograms and you play 60 minutes of vigorous singles tennis: 7 x 3.5 x 70 = 1,715. Sixty minutes x 1,715 = 102,900.