Alternating lunges hit your butt, hips, hamstrings, and those stabilizing core muscles. This one's great to get you ready for the weighted legwork you'll get into later. Remember to do this move slowly, with your torso upright. You'll get a lot more out of it that way. From standing, step one foot far in front of you, lunging deep enough that your back knee kisses the ground and your front thigh is parallel to the ground.