The lunge is a compound movement that works a variety of muscle groups in one exercise. The lunge targets the quadriceps, the major muscle group at the front of your legs. Your quadriceps are a large muscle and responsible for enabling your body to perform explosive, powerful movements. If done without proper technique, the emphasis can be taken off the quadriceps and placed on the glutes.
Muscular Anatomy
The quadriceps are a group of four muscles that sit on the front portion of your thigh. They are the vastus medialis, vastus intermedius, vastus lateralis and rectus femoris. The vastus medialis is the innermost muscle and gives your quadriceps a teardrop-like appearance. The vastus intermedius is the inner portion of your thigh and lies under the rectus femoris. The vastus lateralis is the outermost portion of the quadriceps. When flexed, you can see and feel your vastus lateralis. The rectus femoris is the largest of all four muscles. It originates on your pelvis and crosses your hip joint.
Execution
A body lunge can be performed without any additional weight from a barbell or dumbbells. Stand with your hands on your hips and feet slightly apart. Lunge forward with your right leg. Strike with your heel first, then your forefoot. Lower your body by flexing your hip and knee of your right leg until your left knee is almost touching the floor. Extend the hip and knee of your right leg and return to the starting point. Step forward with your left leg and repeat.
Function
The quadriceps extend or straighten your knee. The rectus femoris acts as a hip flexor and is activated as you lower your body by flexing your hip and knee. The vastus medialis acts as a stabilizer and supports your knee joint during the lowering portion of the lunge. The vastus intermedius and lateralis are activated as you extend your knee and raise your body.
Considerations
The width of the lunge affects if your quadriceps are the main focus. Taking a wider step and increasing the distance between your front foot and back foot places the emphasis on your gluteus maximus, instead of your quadriceps. Your knee should point in the same direction as your foot throughout the lunge to allow proper quadriceps recruitment.
