The Shin Box shape is the ultimate hip mobilizer plus it’s the best way to retrain your squatting pattern from the ground up. Consider it the best glutes exercise you’re not doing!
The 90/90 shape on the floor winds both hips into rotation, something most trainees desperately need especially if they suffer from chronic back pain. The front leg is externally-rotated and the back leg is internally-rotated. These extreme joint angles put your body at a mechanical disadvantage meaning the stronger you get here, the stronger you’ll be on your feet. Adding a squat to this position will strengthen imbalances between sides, level the pelvis & provide a complete hip workout.
Start by using a stick, pole or PVC pipe to self-assist with your upper body. Then bear-hug a medicine ball for counter-balance and core activation. Progress further by holding a weight at chest-level. Start with a 25-50 pound bell and slowly build up to 100-pound plus. Please be patient with this exercise. There’s a big learning curve but the payoff down the road is nothing short of a mobility miracle. My favorite variation is the Shin Box to Lunge to Squat Flow. Do 1 rep/side for 10 straight minutes for a legendary lower body mobility workout.