Overhead Squat Problem #2: Torso Position
Here is another tip from Tabata Times that might help you with your overhead squat lift today.
Forward leaning torso, armpits facing the floor, toes flared out. Not so good. At least he seems happy.
You begin your squat with the bar overhead in a perfect position, arms straight, torso completely vertical, armpits facing forward, shoulders packed in. Then as soon as you begin to lower your body down, your arms rotate forward and your armpits end up facing the ground.
This can put your shoulder in a compromised position, placing a large amount of the strain on the anterior side of the joint — not to mention that yes, this is the major cause of you dumping most of your weights in front of you. You can probably get away with this when the weights are light, but as soon as the they become substantial enough, you will not be in a position that is capable of supporting the load. This is most likely not due to the mobility of the shoulder or lack thereof, but the torso angle changing from completely vertical when standing to much farther forward as you begin to squat.
There is no easy fix here; it is just going to take hard work. Take a light bar or PVC pipe and put it overhead in a perfect position. Torso should be vertical, arms should be straight, and armpits should be facing straight ahead. Face a mirror and begin the slowest squat of your life. Move down at literally an inch a second, and then come back up as soon as you start to see your armpits rotating down towards the ground. Assume the perfect overhead position again and then squat again. Fight to stay vertical. You should be able to get a little lower with each rep, even if it is just a 1/2 inch each time, take it. Once you reach a point where there is no more noticeable improvement or fatigue has set in to the point where you can no longer hold a good position, take a break. Repeat this process 3 times every other day and you will gain the ability to stay vertical in your squat and keep your shoulders healthy.