Adductor: Sit next to the wall, sideways, turn and lay down. Butt should be against the wall, knees straight. Let gravity do the work for you.
Quad/Hip Flexor: Drag your knee down the wall(the closer to the wall, the more intense the stretch) and raise the arm of the side of the down knee. Your other leg should be planted and bent at roughly 90 degrees.
Hamstring: Lay down, keep your bottom leg bent until your raised leg is in position, straighten the raised leg first, then straighten the bottom leg. Bend the bottom leg first when coming out of the stretch.
Piriformis: Drop one leg down onto the bench at a 90 degree angle, you can bend forward for a more intense stretch if need, just make sure you keep your back flat and chest high(don't round the back or "crunch" your abs).
Calf(Gastrocnemius): Lean forward and lead with your hips(think about pressing your waist forward not your chest), raising the knee makes it even more effective. Make sure your heel is on the ground and the ball of your foot is on the frame, foot should be at about a 45 degree angle.
These stretches should be held from 30 seconds to as long as you like. These are best performed as a cool down or totally separate from your workout, but if a muscle is particularly tight, it's ok to do a static stretch for it before working out.
