Kneel down on all fours, hands under shoulders, knees under hips with a band around your lower thighs just above the knees
Maintaining a bend at your knees drive your left heel upwards until the thigh is parallel to the ground maintaining tension on the band throughout the movement - this is your start position
Bring your knee down to halfway - this is your end position
Return to start position, alternate sides and repeat desired number of reps