First you need to make sure that you actually have set a training intensity. The first one (one green bar) is rest, so will not affect your players. When you have set the intensity, flip to the excercises and hit Stretching, Cardio and Practise match after each other. Flip back to your squad view and you will see the Gain. If you are lucky you even have some players that got one or more skill points, if you are unlucky they just got injured.