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.
Based on the the list of 4 tennis activities, shown below, the average calories burned for an average male, weighing 190 pounds (86 kg) is 246 Calories for 30 minutes of tennis. The average burnt for an average female, weighing 163 pounds (74 kg) is 211 Calories for 30 minutes of tennis.