for flexability, you just need to do a lot of different stretches, the best one for your legs and back, is to sit on the floor, spread your legs as far as you can, keeping your legs straight try to wrap you fingers of both hands around one foot, it is important to sit up stright after and repeat this with each leg at least ten times but no more than 20 when you first start, also leaning backwards over the end of the bed, so your head is near the floor stretches the muscles in your back, and stretch you legs towards the ceiling one at a time, this will help with you core muscles too, hope that helps