Bind a Loop Band to the door with the specific Utility Strap, taking care to fix the band below your pelvis level.Back about 1,5 meters away from the door so as the band is slightly under tension.
Starting from the upright position, make a large step backwards, placing first your toe on the floor and then brushing the floor with your knee. NB: the knee touches the ground but it is not in support.
8 per each side (better not to alternate) x 3 sets
The step backward is not wide enough.