Well, I have also tried shotokan before, but I am not exactly sure which one of the both styles requires more strength. Matsubayashi ryu uses a lot of nekwashi dachi, which poses problems to some people because it requires very strong legs. The sensei probably didn't mean anything bad. He was probably just trying to emphasize how important it was to practice constantly. Anyway, I usually come one hour before training in the dojo and actually do some basic movements exercises. I also try to do as many exercises as possible at home every day. And yes, everybody here probably very is right saying: practice, practice, practice.