Prepare the BOSU with the round side up Take the position of a lunge, leaning your front foot against the centre of the BOSU. Firm up your body core and keep the correct lunge position.
From the starting position shift the weight onto the front leg with the foot on the BOSU and stand only on that leg. The free leg, the one in the back goes to the front and up, slightly bent. When you are standing on the BOSU keep your body upright. From the position standing on one leg, return to the lunge while moving your leg backward and to the floor. Control the back step to have about a 90 degree angle at the knee joints of both limbs in the lower position. Inhale going down and exhale going up. Do the required number of repetitions with one leg and then switch legs and do the same number of repetitions with the other.
Pay attention to the essential posture and fix your body core muscles.
Do the backward movement along animaginary line of the essential posture, without rotating in or out.
The front leg knee must not go beyond the toe line and pay attention to the correct angle at your knee joint.
Exercise sideways to a mirror to check and correct the technique.
To practice the correct technique it is better to first learn the correct posture in a static lunge position.