Is the Smith machine really safer? A closer look at this popular gym equipment

The Smith machine is a common sight in gyms and is often used by people who believe it offers a safer alternative to free-weight exercises like the Bench Press and Squat. But is it actually safer?

While the Smith machine does offer some “assistance” by guiding the bar along a fixed path, this doesn’t necessarily make it safer. In fact, the forced trajectory can work against your body’s natural mechanics and lead to joint stress or improper muscle activation.

Bench Press: free weights vs Smith machine

Let’s take the Bench Press as an example. When performed correctly with a free barbell, proper technique involves creating a natural arch in the back to keep the scapulae retracted and depressed (i.e., pulled back and down, away from the ears). You begin by unracking the bar, positioning it roughly in front of your nose, and lowering it slowly until it touches the chest, typically around the nipple line.

Trajectory of the barbell during the Bench Press

Now, here’s an important detail: the bar does not move in a straight vertical line: it follows a slight arc that reflects the body’s natural biomechanics.

With the Smith machine, however, the bar is locked into a perfectly vertical trajectory. This restricts movement and may place unnatural strain on the shoulders, elbows, or wrists. As a result, muscle activation can be compromised, and joint stress may increase.

Squatting on the Smith Machine: Two Common Variants

Now let’s talk about the squat, another classic movement often performed on the Smith machine. There are generally two ways people use it for squats:

1. Traditional Back Squat imitation: this mimics a free-weight Back Squat.

2. Feet-Forward Squat: The feet are placed well in front of the bar, and the torso stays vertical as the bar travels straight down.

   
   

In the first case, the Smith machine can slightly alter the natural bar path, but it might still serve as an initial learning tool for beginners. However, it removes the need for stabilisation, balance, and coordination, key components of a proper Squat. The strength developed using a Smith machine doesn’t transfer well to free-weight squats. That’s why, when someone tells me they can squat 100kg on the Smith machine, I often smile inwardly.

The second variation, the vertical squat with feet far forward, is sometimes promoted as a “safer” alternative. But this is misleading. From a physiological standpoint, this setup disrupts normal spinal and pelvic alignment:

Feet-Forward Squat on a Smith Machine

• Spinal safety concerns: the human spine has four natural curves: cervical lordosis (inward), thoracic kyphosis (outward), lumbar lordosis (inward), and sacral kyphosis (outward). These curves help the spine absorb load and maintain stability. When you eliminate one, such as the lumbar curve by keeping the back too upright, you compromise the spine’s ability to support weight. So positioning the feet far ahead just to keep your back perpendicular to the floor, flattening the lumbar curve in the process, is a major mistake.

• Hamstring activation issues: in a natural Squat, the Hamstrings play a key role in stabilising the knee and supporting hip extension. When you alter the mechanics and reduce their involvement, the Anterior Cruciate Ligament (ACL) is left to bear more of the load, which increases injury risk.

Conclusion: machines aren’t always safer

To sum up, it’s time to challenge the widespread belief that machines, particularly the Smith machine, are inherently safer than free weights. While machines can assist movement, they often do so by forcing unnatural joint mechanics. Over time, this can lead to poor movement patterns and potential injuries.

Don’t view the gym solely as a place for building bigger muscles (unless you’re specifically training for bodybuilding competitions). Instead, see it as an opportunity to improve strength, movement quality, coordination, and control, all of which carry over into everyday life.

Don’t just seek out the “easiest” exercises. Learn how to perform the more complex, compound movements that develop true functional fitness.

Sources:

• Schwanbeck, S., Chilibeck, P. D., & Binsted, G. (2009). A comparison of free weight squat to Smith machine squat using electromyography. Journal of Strength and Conditioning Research, 23(9), 2588–2591.

• McGill, S. M. (2002). Low Back Disorders: Evidence-Based Prevention and Rehabilitation. Human Kinetics.

• Escamilla, R. F. (2001). Knee biomechanics of the dynamic squat exercise. Medicine & Science in Sports & Exercise, 33(1), 127–141.