Turbo fire - stretch question

Debx12345

I have just got turbo fire and did the first one of turbo 20, today is down for stretch 40, I am limited on time and want to get the best out of workouts, ie burning fat and gaining muscle, now I know doing stretches before and after workouts are important, but why do I need a full 40 mins of them ? when I could do a 40 min of burning cals.

As I said I am limited on time, normal spend 40 mins a day doing some exercise to burn cals etc, will doing these stretches really do much ?

Thinking of skipping the long stretches sessions, but wanted Someones advice on if I should really do them and why.