If you utilize an excessive amount of weight, you may begin bouncing at rock bottom of every rep or fail to complete the rep with a tough contraction at the highest. (mensquats.com)
Knees will travel so that they are directly over, or just slightly beyond, your toes at bottom of rep (kingofthegym.com)
Make sure to stretch fully and straighten your arms at the bottom of each rep — don't forget that the negative or eccentric portion of the movement is as crucial to growth as the positive one. (fitnessandpower.com)