The Back Squat is one of the most popular bilateral, lower body exercises. However, every individual presents different limitations affecting the movement. Various tools can be utilized to combat these limitations.
One tool we use to enhance depth recognition during the Back Squat is a box. Varying box heights can accommodate depths depending on the individual. @iamsull is using the box during his training session to control his depth and maintain the quality movement.
Another tool we use is the heel lift. Raising the heels promotes increased range of motion through the ankle, improving the depth of the squat, seen by @scuhlir.
These tools are among others we utilize frequently. These can also be applied to other squat various such as Front Squats or Safety Squat Bar Squats.