Ribeiro, Alex S. PhD; Santos, Erick D. MSc; Nunes, João Pedro MSc; Nascimento, Matheus A. PhD; Graça, Ágatha MSc; Bezerra, Ewertton S. PhD; Mayhew, Jerry L. PhD

Strength and Conditioning Journal 45(1):p 58-66, February 2023. | DOI: 10.1519/SSC.0000000000000709

PURPOSE:

To analyze the effect of the barbell, machine, and other squat variations/tools on lower-limb muscle hypertrophy via current literature and applicable research studies.

CONCLUSIONS:

§ The squat is an effective exercise for inducing hypertrophy of the quadriceps, mainly the vastii, but also the rectus femoris with a reduced magnitude.

§ Little to no evidence exists supporting hamstring hypertrophy from the back squat only.

§ Few longitudinal studies exist relative to hypertrophy of the gluteus maximus in the squat and the limited evidence that is available recommends squatting deeper may augment gluteus maximus hypertrophy.

§ On that, squat depth beyond 90° of knee flexion may not provide further hypertrophy of the knee extensors.

§ Despite the popularity of the many squat variations, there are still controversies surrounding their hypertrophic potential for lower-limb musculature.

§ Further studies are needed to investigate the hypertrophic effects of different squat variations, as well as differences in hypertrophy because of squat depth, stance, barbell position, and different squat apparatuses/machines.

PRACTICAL CONSIDERATIONS:

§ Adding squat exercises to induce hypertrophy in mainly the quadriceps and to a lesser extent the gluteus maximus muscles is advised.

§ Performing the squat at a 90°–120° knee ROM may induce optimal effects on vastii muscles but to a lesser extent of the rectus femoris.

§ Squatting at full depth may provide additional increases in gluteus maximus size.

§ The hamstrings and plantar flexors (calves) tend not to increase with squat training.

§ Squats can be performed in different ways concerning the barbell position (e.g., high-bar, low-bar, or front-bar), stance width (e.g., narrow or sumo squat), apparatus (e.g., sissy, hack, v-squat, belt, or Smith machines), and others (e.g., single-leg squat or Bulgarian squat).

§ Further studies are needed to compare the effects of these variations, given we did not find any longitudinal study concerning variations other than the barbell back squat and flywheel belt squat.

§ One can include different squat variations in their training schedules when aiming to train the quadriceps and the gluteus maximus muscles, although little evidence is available on the magnitude of the hypertrophy on each muscle portion for each variation within the squat pattern.

§ Some recent studies have observed that varying exercise selection throughout training sessions may promote slightly greater hypertrophic responses and perceived motivation compared with fixed or nonvarying exercise selection conditions.

§ It is recommended that the squat selection variation be an integrated and cohesive approach designed to target each muscle group using sound rationales based on trainee goals and biomechanical principles.