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.
So where does the fastest tennis serve rank among other sports? It is ranked third, trailing behind badminton with a fastest recorded smash of 89 m/s (199 mph) and jai-alai, where a pelota was thrown at 84 m/s (188 mph) in 1979. Hockey and squash are tied for forth place with speeds up to 54 m/s (120 mph).