Smith Machine Squats vs Barbell Squats: The Differences Explained

published by: Debbie Luna
Last Updated:
May 12, 2022

Though the barbell squat is considered the king of lower body exercises, some debate surrounds its comparison with the smith machine squat and whether one is superior over the other in certain aspects of training.

In actuality, the smith machine squat and the barbell squat are simply two variants of the same compound movement - with any differences in form, mechanics or training stimulus being primarily due to the equipment involved in the exercises themselves.

As such, the actual effectiveness and suitability of the smith machine squat and the barbell squat will depend on the particular needs of the exerciser, with such factors like muscle group recruitment, training intensity and the exerciser’s own athletic experience being brought into consideration.

What is the Smith Machine Squat?

The smith machine squat is, unsurprisingly, a variation of the squat exercise that makes use of the smith machine, a type of exercise equipment quite similar to a squat rack save for the fact that the barbell is firmly attached to the rack, thereby restricting its range of motion to a rather narrow vertical path.

smith machine squat benefits

Much like its free weight counterpart, the smith machine squat is a compound movement with a closed kinetic chain that is performed for the purposes of inducing muscular hypertrophy and strength developments in the lower half of the body - with a particular focus on the quadriceps, glutes and hamstring muscle groups.

Though it is somewhat less recommended by athletic coaches towards higher level athletes, the smith machine squat is nonetheless quite effective at the particular characteristics that set it apart from other lower body compound exercises, making it a solid exercise for the majority of training programs.

What is the Barbell Squat?

The barbell squat, occasionally referred to as the king of all exercises, is a lower body compound exercise with a closed kinetic chain that makes use of free weight resistance equipment so as to induce a nearly unparalleled effectiveness of training stimulus in many leg muscle groups.

barbell full squat

Due to its popularity and effectiveness, the barbell squat is incorporated into a large number of workout programs primarily as the main lower body training movement in the program - and usually at an intensity that is significant enough to require high levels of exertion.

Just like the smith machine squat, barbell squats activate the same muscle groups in a similar pattern; with such muscle groups like the quadriceps, glutes, hamstrings and even the lower back being recruited to great extents during every repetition.

Do the Barbell Squat and Smith Machine Squat Train the Same Muscles?

Muscle group activation is one of the most important aspects of an exercise, with a different angle of resistance, load distribution or even level of complexity all regulating which muscle groups are recruited during an exercise, as well as to what extent.

In the case of someone comparing two different exercises, a vitally important question to ask is whether the muscle group activation set and pattern are similar, with the barbell squat and smith machine squat being particularly applicable in this situation.

The muscle group activation sets of both the barbell squat and the smith machine squat share many of the same characteristics, with the quadriceps femoris muscle group, gluteus muscle group, hamstrings muscle group acting as the primary mover muscle groups.

This is where the two exercises begin to deviate from one another, however, as the smith machine (and machine based exercises in general) utilizes stabilizer muscle groups to a far less significant extent than the free weight barbell squat, presenting a difference in muscle groups recruited during each movement.

The barbell squat also activates the hip adductors, hip flexors, and the calves in a secondary or stabilizing capacity throughout the entirety of each repetition - something that is otherwise not applicable during the smith machine squat, as the barbell stabilizes itself and the exerciser is forced into a somewhat different range of motion.

Are the Mechanics and Form Cues of the Barbell Squat and the Smith Machine Squat Identical?

Due to the rather fixed bar path and reduced range of motion involved in the smith machine squat, the exerciser will find that the form and mechanics of the two squat variants in question are somewhat different.

During the smith machine squat, the exerciser will have to adopt a stance and foot placement wider and more forward than they would be safely capable of doing during a standard barbell squat - thereby increasing gluteus and hamstring muscle group activation, but also increasing the risk of knee joint injuries.

smith machine squat

This exercise’s mechanics, while improving the muscle group activation of the posterior chain, will also reduce or entirely alienate the usage of many stabilizer muscle groups normally trained in the barbell squat, such as the erector spinae, the majority of the abdominal stabilizers, and the calves to some extent.

However, the form and mechanics of the barbell squat may be less appropriate for novice level exercisers or individuals with poor proprioception, as it requires the exerciser to follow a multitude of form cues so as to reduce the risk of injury and maximize training stimulus development.

The most obvious and most important of these is the depth at which the exerciser may reach during the barbell squat, something that would place them at risk of back and knee injuries as the fixed barbell of the smith machine forces the torso to lean forward.

Which Exercise is Better for Building Leg Muscles?

Without a doubt, the barbell squat is considered to be significantly better than the smith machine squat in terms of inducing muscle group activation intensity.

This is demonstrated to be most significant in certain muscles of the quadriceps femoris, hamstrings and calves muscle groups - all of which receive a greater level of stimulus and thus a greater level of improvement from the barbell squat in comparison to the smith machine squat.

Such a difference is due to three factors that hold the smith machine squat back in terms of muscle training effectiveness; its very nature as a self-stabilizing source of resistance, the limited range of motion of the fixed barbell, and the fact that the form of the smith machine squat is not a natural movement for the majority of individuals.

These factors are otherwise not present in the barbell squat, as its usage of free weight implements (namely the barbell) recruits stabilizer muscles to an impressive degree, allows for a full range of motion to be achieved in accordance to the exerciser’s own biomechanics, and concurrently also follows the natural motions that an exerciser’s legs are shaped to perform.

Which Exercise is Safer to Perform?

Though both exercises are considerably safe and present low risks of injury when performed in an appropriate manner, it is the smith machine squat that is least likely to result in significant injury.

This is a direct benefit of the fact that it makes use of a smith machine, which will usually feature a number of safety mechanisms specifically built into the equipment in order to reduce or eliminate the risk of an exerciser injuring themselves in a certain way.

Alongside these safety mechanisms is the fact that the form of the smith machine squat is far more forgiving, save for the caveat that the exerciser’s foot stance is wider and more forward than in the barbell squat, placing additional pressure on the knee joints.

As such, if the exerciser is of novice experience, uncomfortable with the form of the barbell squat, or an athlete recovering from an injury; the smith machine squat is the safer of the two choices.

Why is the Smith Machine Squat Used as a Barbell Squat Substitute?

In the case of an exerciser needing to substitute out the barbell squat, one of the potential alternative exercises is that of the machine squat - usually in combination with a far lower intensity secondary exercise in order to make up for the difference in muscle group recruitment.

Replacing the barbell squat with the smith machine squat over other exercises is usually due to two primary reasons; either the exerciser has developed an injury that prevents them from performing a full repetition of the barbell squat and thus requires the partial repetition potential of the smith machine squat, or the exerciser wishes to utilize the self-stabilizing barbell of the smith machine.

Apart from these specific circumstances, it is usually a better choice to replace the barbell squat with another free weight exercise that better replicates its intensity of training and muscle group activation pattern.

Advantages of the Barbell Squat

The barbell squat is often performed instead of the smith machine squat for good reason - as its particular advantages over the latter exercise make it far more useful for the general purposes of most exercisers, losing out only in certain niche circumstances or specific training purposes.

Better Overall Training Effectiveness

The barbell squat has been definitively demonstrated in a multitude of studies to activate muscle groups in a far more significant capacity than the smith machine squat, placing it as the clear winner in terms of muscle hypertrophy and strength development.

The sole instance wherein the smith machine squat may be more effective is in the case of the exerciser wishing to shift a larger portion of the resistance to the posterior chain - a circumstance that, while fulfilled by the smith machine squat, is also better done with another free weight exercise instead.

Superior General Athletic Carryover

For powerlifters, athletes and similar individuals that perform exercises for the purposes of improving their physical capacity in sport or labor, the barbell squat is greatly superior to the smith machine squat.

This is due to many of the aforementioned differences in this article, such as a larger range of motion and recruitment of stabilizer muscle groups training the athlete in a functional manner that is otherwise not applicable with the smith machine squat and other lower body machine based movements.

As such, in comparison to its smith machine counterpart, the barbell squat is the better choice for developing the exerciser’s athletic and physical capacities.

Advantages of the Smith Machine

Even if the smith machine squat is not as effective as the barbell squat in terms of training effectiveness, it is still capable of outshining its free weight counterpart in the context of certain situations or by fulfilling a particular training goal that may be difficult with the barbell squat instead.

Better Specific Muscle Group Activation (Hamstrings and Glutes)

Though it is well established that the barbell squat activates the majority of lower body muscle groups to a far more intense extent than the smith machine squat, the latter is still capable of exemplifying the hamstrings and glutes muscle groups due to its altered form.

As it is the quadriceps femoris that are most significantly trained during the barbell squat, the ability of the smith machine squat to balance and stabilize itself can allow the exerciser to adopt a foot stance wider and more forward than what would be possible with the barbell squat - thereby recruiting the hamstrings and glutes more significantly.

Supramaximal Loading Potential

Because of the self-stabilizing nature and shorter range of motion involved in the smith machine squat, exercisers wishing to move an amount of weight far heavier than what they would be capable of with free weight exercises may do so with the smith machine squat itself.

This allows for what is referred to as supramaximal eccentric loading training, wherein the exerciser will perform a negative repetition far heavier than what they could lift concentrically (or with a barbell), thus inducing a novel and highly effective training stimulus quite suitable for powerlifters and similar strength based athletes.

Conclusion

Though this article focuses primarily on which exercise is better than the other, many higher level exercisers and athletes find that they can best benefit by combining the two exercises in a manner that reduces stabilizer muscle group fatigue and pressure on the joints - all while still retaining an intense training stimulus.

Regardless of which choice one makes, both the smith machine squat and the barbell squat present much of the same requirements in order to perform safely; warm-ups, a flexibility routine, usage of proper form and the supervision of a trainer or coach, if so needed.

References

1. Gene-Morales, Javier & Flández, Jorge & Juesas, Álvaro & Gargallo, Pedro & Miñana, Ivan & Colado, Juan C.. (2020). A systematic review on the muscular activation on the lower limbs with five different variations of the squat exercise. Journal of Human Sport and Exercise. 15. S1277-S1299. 10.14198/jhse.2020.15.Proc4.28.

2. Saeterbakken AH, Olsen A, Behm DG, Bardstu HB, Andersen V. The short- and long-term effects of resistance training with different stability requirements. PLoS One. 2019 Apr 1;14(4):e0214302. doi: 10.1371/journal.pone.0214302. PMID: 30934001; PMCID: PMC6443166.

3. Schwanbeck, Shane & Chilibeck, Philip & Binsted, Gordon. (2009). A Comparison of Free Weight Squat to Smith Machine Squat Using Electromyography. Journal of strength and conditioning research / National Strength & Conditioning Association. 23. 2588-91. 10.1519/JSC.0b013e3181b1b181.

Debbie (Deb) started powerlifting and Olympic lifting in High School as part of her track team's programming; She continues to train in order to remain athletic. Inspire US allows Deb to share information related to training, lifting, biomechanics, and more.
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