Lie face up, with your back flat on an exercise mat, your legs extended out in front of you. Bend your right knee so you can place your right foot flat on the floor. Place one end of a long resistance band around the sole of your left foot and grip the other end firmly in both hands. Keeping your leg fully extended bring it up overhead until your thigh is at roughly a 90 degree angle to the floor. Use the resistance band to increase and deepen the stretch in your hamstring. Hold for the recommended amount of time, then repeat on the other side.