ditto. i can do 300 pounds in my deadlifts... but 225 with good form.all those cruicual leg lifts you need to be REALLY careful, you can fuck up your back.... ive done it before! your midsection may not be as strong as your legs... make sure youre doing cruicial ab work and lower back work, thats where i went wrong.
You should probably even take the bar away to get the form down. Squatting properly is a tough movement because it involves so many muscles and joints.
Stretching will help as well - you likely have tight hammies and glutes, which are forcing your lower back to flex when you get too low. The key is to work within your comfortable range of motion without allowing that to happen and just gradually over time you will be able to get lower and lower once the proper muscles are stretched and strengthened.
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