Squats and lunges are co-rulers of the leg-building empire. Ideally, you'll find time for both in your lower-body strength-building routine, but if you only have the time or patience for one -- how do you choose? Neither exercise is truly superior to the other, but one may be better suited to specific fitness goals.
The squat is a basic exercise that every beginner should master. It works the quadriceps, gluteus maximus, inner thighs, hamstrings and calves. It mimics the movement of sitting in a chair, and requires less balance and coordination that the stepping forward action of the lunge. A squat is also modifiable for beginners who need to master proper form to prevent injury. Stability ball wall squats, in which you place a large, inflated exercise ball between the small of your back and the wall as you drop your hips and bend your knees, can help you learn proper form.
Function and Muscle Activation
If your goal is to target a greater number of muscles and build sport-specific function, the lunge is for you. Lunges train athletes to move skillfully and powerfully in multiple directions. If you step forward into a short lunge, the primary muscle targeted is the quadriceps at the top of the thigh. Step forward for a long-distance lunge and you place more emphasis on the gluteus maximus, the largest buttock muscle. Side lunges place slightly more emphasis on the adductor, or inner thigh, and abductor, or outer thigh, muscles. Lunges require greater stabilization and thus engage the small pelvic stabilizers of the gluteus minimus and gluteus medius. Stabilization also comes from the muscles of the core, including the internal and external obliques and the quadratus lumborum of the lower back.
Squats are a favorite of body builders, such as eight-time Mr. Olympia Ronnie Coleman and the infamous Arnold Schwarzenegger. You can lift more weight while squatting than you can lunging. Heavy barbell and dumbbell squats stimulate your body to release significant amounts of growth hormone, which can help boost muscle growth all over, not just in your legs.
Because you should strength train all the major muscles in your body at least two times per week on non-consecutive days, you have room for both moves in your routine regardless of your goals. At one session, you could emphasize squats and at your second session, emphasize lunges. Beginners may stick to squats at all strength-training sessions until they feel strong and skilled enough to lunge. If you train legs three or four times per week, you can emphasize the lower-body exercise that is most appropriate for your goals at the additional sessions.