First of all, itīs a total different game to play to 3*15 than 5*7. Youīll need more stamina and the ralleys become longer. Therefore our training is changed to include longer ralleys. The first three strokes in every ralley is very important in menīs doubles. It was even more important in 5*7 than 3*15.
I think the right length of the menīs doubles game is 5*9.