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.
The tennis activity with the lowest calories burnt is table tennis, ping pong, which for an average man in one hour burns 345 Calories, and for an average woman burns 296 Calories. As previously mentioned the burnt calories will be based mainly on your weight, the intensity of your activity and the length of time.