For quad growth
For quad growth, hack squat rates well ahead on our research criteria: more of the work on the quads, more stretch.
Both are good choices that train the quads the same way, so they swap freely. Rotating between them every few weeks is an easy way to vary your training.
The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work
Hack Squat. Deep knee bend under stable, heavy load: the quads are clearly the limiter.
Smith Machine Squat. A squat on rails, so you can place your feet forward and push the quads hard without balancing a bar.
For quad growth, hack squat rates well ahead on our research criteria: more of the work on the quads, more stretch. Both are good choices that train the quads the same way, so they swap freely. Rotating between them every few weeks is an easy way to vary your training.
About the same: both are easy to learn.
Hack squat needs a machine, so for most people it’s a gym exercise. Smith machine squat needs a Smith machine, so for most people it’s a gym exercise.
About the same: both rate Strong for joint and recovery cost in our research rubric.