Today is pain day. Start with a wall sit until you drop. Take three minutes and then do deep and high squat hops. As many as possible. One set. Then one legged squats, simply hold a leg up any way that you like. Do 10-25 on each leg. Do four sets and take 2 minutes in between. Last are as deep as possible sumo squats with a reach. That means feet are wide and reach your arms over head at the top of the movement to engage your abs. Do 15-30 reps with two sets with 90 seconds in between.