Although often referred to as a collective, your quadriceps is actually a group of four muscles: the rectus femoris, vastus lateralis, vastus intermedius and vastus medialis. The quadriceps' primary function is knee extension, or straightening a bent leg, although the rectus femoris also assists with knee flexion. In order to stretch your quadriceps, you reverse the joint motion each muscle performs.
Basic Stretching Technique
No matter which muscle you're stretching, you should still follow a few basic technique guidelines. Stretch each muscle to the point of mild tension, not pain, then hold the stretch for 10 to 30 seconds, breathing normally. Repeat each stretch a total of three to five times, and remember to stretch both sides of your body. You should always warm up before stretching, too; this makes your muscles more pliable and flexible. Post-workout or after a brisk walk or hot shower are all good times to stretch.
Standing/Lying Quadriceps Stretch
You can do this quadriceps stretch almost anywhere, and because it allows both knee flexion and hip extension, it targets all four quadriceps muscles at once. Stand on one leg and bend the other knee, reaching back with the same-side hand to draw your heel in toward your buttock on that side. Think of pushing your hips slightly forward; your bent knee should point straight down. The downside of this stretch is that it requires you to balance on one foot. Either hold onto something sturdy for balance, or perform the same stretch in bed, lying on your side and stretching the uppermost leg.
Kneeling Stretch
If your rectus femoris isn't tight but your other quadriceps muscles are, you can focus on them by performing knee flexion only, without full hip extension. This is also an excellent stretch if your rectus femoris is so tight that achieving full hip extension is difficult for you. Kneel with your toes pointed, feet and legs about hip-width apart. Your thighs should be directly over your calves, buttocks on your heels; don't let your knees twist in or out. Keep your back flat as you lean back gently from the hips, although your body won't straighten completely.
Kneeling Lunge
This stretch emphasizes the rectus femoris and your other hip flexors including the iliopsoas, which is actually two muscles, the iliacus and psoas. Assume a kneeling lunge position with both knees bent at 90 degrees, front foot planted flat on the floor, back knee directly beneath your hip, toes pointed so your back foot can rest comfortably on the floor. If you're kneeling on a hard floor, you may want to put an exercise mat or yoga mat underneath your back knee. Intensify the stretch by keeping your torso upright -- don't hunch forward or arch your back -- and pushing your back hip slightly forward.
