Smith Machine vs Free Weights: Is the Smith Machine Worth Using?

In a small randomised crossover study, an 8-repetition-maximum free-weight squat produced higher EMG activity than the Smith squat in the gastrocnemius, biceps femoris and vastus medialis, and 43% higher activity averaged over all measured muscles ^[1]. In the bench press, a study of the pectoralis major and the anterior and medial deltoids reported greater medial deltoid activation with free weights than on the Smith machine ^[2].

These are acute measurements in small samples. EMG amplitude shows how strongly a muscle is activated during a set; it does not predict long-term muscle growth on its own. Treat these findings as a description of the movements, not as proof that one builds more muscle.

In a study of 32 men and women, squat one-repetition maximum (1RM) was higher on the Smith machine than with free weights, while bench press 1RM was higher with free weights ^[3]. Likely explanations are that the fixed bar path removes the balance demand of the squat, while in the bench press the fixed vertical path differs from the curved bar path most lifters use — but the study measured loads, not mechanisms.

Practical consequence: do not expect your Smith numbers to equal your barbell numbers. Track them separately, and use percentages of your Smith 1RM when programming Smith work.

A systematic review and meta-analysis of 13 studies comparing free-weight and machine training for at least six weeks found no differences in strength or hypertrophy overall; strength tested with free weights improved more after free-weight training, and machine-tested strength tended to improve more after machine training ^[4]. Our article on machines vs free weights covers this in detail.

Smith-specific training studies are still few. In an 8-week study, squat training with free weights or a Smith machine did not change how lifters directed their force in either squat type, leading the authors to conclude both variations can be used interchangeably for that outcome ^[5]. In single sessions, Smith squats produce a larger backward (posterior) force component than free-weight squats, and the difference grows with heavier loads ^[6].

A 2026 crossover study in 19 strength-trained men compared identical squat sessions (4 × 9 at 70% 1RM) on a Smith machine and with free weights. Velocity loss and perceived effort did not differ, but the free-weight session produced greater peripheral and central fatigue in the knee extensors afterwards ^[7].

If similar adaptations come with less fatigue, the Smith machine may be an efficient way to accumulate leg volume. This is one acute study, so treat it as promising rather than established.

Our Smith machine buying guide compares combination units and standalone Smith machines; if you mainly want free-weight lifts, our squat rack buying guide covers racks with safety arms.

The Smith machine is neither a cheat nor a perfect substitute. It changes the movement — more stability, a fixed path, different maximal loads — and those changes make it useful for safe, hard hypertrophy work and for solo training.

Use it as a main lift if muscle is the goal, alongside free weights if barbell strength is the goal, and judge it by your progress over months rather than by single-session activation data.