For quad growth
For quad growth, hack squat rates well ahead on our research criteria: easier to progress, easier on the joints.
Both are good choices, and they train the quads differently. Using both across your week covers more of the muscle than either alone: in studies, varied exercises grew parts of a muscle that one exercise missed. (Fonseca et al., 2014; Costa et al., 2021)
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.
Sissy Squat. The knees travel far forward and stretch the quads hard, but it’s tough to load and stresses the knees.
For quad growth, hack squat rates well ahead on our research criteria: easier to progress, easier on the joints. Both are good choices, and they train the quads differently. Using both across your week covers more of the muscle than either alone: in studies, varied exercises grew parts of a muscle that one exercise missed.
Hack squat is easier: it’s easy to learn, while sissy squat takes some practice.
Hack squat needs a machine, so for most people it’s a gym exercise. Sissy squat needs no equipment, so you can do it anywhere.
Hack squat: it rates Strong for joint and recovery cost in our research rubric, against Good for sissy squat.