Training consum to much energy 

1 training and all my energy is gone

or maybe it's me who don't understand how to use my energy to train

i think that's because you use all 100 energy on only 1 training. try to distribute them evenly like use 25 for each and u train every single one for 25 points. or if u want a more aggressive style u can use 100 on strength but i don't know how good that is.