HOW: You are going to be moving in a straight line forward and backwards with this exercise. Step backwards into a posterior lunge position. Drive your front leg into the ground and push yourself back up. Immediately step forward into an anterior lunge with the same leg you stepped back with previously. Push your self back up to the starting position and repeat.
FEEL: You should feel all the muscles in your legs working, especially the one that is always in front.
COMPENSATION: Don't let your knee cave in or bow out, focus on good trunk and torso position the entire time. Do not lean side-to-side.