Many strength and muscle building experts will say, the barbell back squat is much more effective at building size and strength. They argue free weight squats are a more natural movement and require much more stabilization and balance, which increases its effectiveness. However, the Smith machine is much easier to learn, especially for beginners, which many argue is safer. I contend that it depends upon the person’s build. If one has long legs and a shorter torso, they will have a very difficult time performing a squat correctly in order to get optimum stimulation for strength or growth. In this case and in others, they would benefit greatly from performing smith machine squats. But what does science have to say? Which is better for gaining strength?
Researchers from the University of Saskatchewan in Canada compared the free weight squat to the Smith machine using electromyography (EMG). The purpose of their study was to determine which exercise was better at stimulating the prime movers and stabilizers of the legs (e.g., tibialis anterior, gastrocnemius, vastus medialis, vastus lateralis and biceps femoris) and trunk (e.g., lumbar erector spinae and rectus abdominus). Six healthy participants performed 1 set of 8 repetitions using a weight they could lift 8 times, i.e., 8 rep maximum.
Contrary to our hypotheses, muscles of the legs (specifically the vastus medialis and biceps femoris) displayed greater EMG activity during the free weight squat compared to the Smith machine squat, whereas there were no differences between exercises for EMG activity of trunk stabilizers.
Researchers conclude that the free weight squat may be superior to the Smith machine squat for training the major muscle groups of the legs and possibly would result in greater strength development and hypertrophy of these muscle groups with long-term training.
Journal of Strength and Conditioning Research, 23(9), 2588-2591.
