Draw your thighs back in line with the ankles so that the deepest part of the footprint falls where the front heels meet the earth. (yogajournal.com)
Slowly bend both knees, lowering your body straight down until both knees make 90 - degree angles, being sure to keep your front knee in line with your ankle. (chloeting.com)
Engage the inner thighs and make sure the knees stay in line with the ankles without tilting out to the sides. (mindbodygreen.com)