To get the most growth in your quads when using the hack squat, don't lock out at the top.
- Set your feet just outside shoulder-width with your toes turned slightly outward.
- Aim to drop your ass to your heels on each rep while letting your torso slide down between your legs.
- Do smooth, continuous pumping reps with no pausing at the top or bottom.
The Absolute Best Way to Build Quads
The 6-12-30 Method for Big Quads