I have been doing box squats for a few weeks to try and improve my glutes and core so my overall squat can improve. I have been getting stronger however today I noticed that as I put on more weight, close to the end of my sets when I dropped down to the box my spine seamed to look slightly curved from the front (I am standing in front of a mirror)
When I try and get off the box with the weight on my back with spontaneous force my left hip seems to raise up on takeoff and my right lags behind, also my left shoulder seems to sink down and the bar looks slightly slanted for a few seconds.
This doesn’t happen with 110pnds on the bar but it shows up when I push to 140+bar. I can do a bit more but I decided to not push it until I figure out why this is happening. Also, my right oblique seems to be a little sore after this.
Anyone have any ideas why this would happen, is my core extremely weak, what might be lagging? I am assuming that there is some sort of imbalance, I was doing minor plank work before, should I add more planks to my program? Currently doing the high frequency training program by Chad.