So, one thing Dan was complaining about was low back pain when he was doing like a heavy squat set. One of the issues was happening. If you watch my lower back here. Is that as he was squatting down, he's coming into a pelvic tilt, rounding out off the back. What happens when you're rounding out the backlight that is the shear forces coming in the lumbar spine, and when that's put under a lot of load is just going to aggravate the area, you're going to walk away from a set, just feeling tightened pain. Two things that you need to make sure that you do one, you make sure you have the rigidity, the spine, the bottom of the squat. So, when you come down, you're watching yourself in the mirror to make sure that your lumbar spine stays straight. How you get that done is you drive your knees out and you maintain core stability. If you do those two things, it'll fix your low back pain and squats.