Hack Squat (Machine)
The Hack Squat Machine is a compound lower-body exercise that targets the quadriceps, glutes, and hamstrings using a sled-style apparatus. It provides a fixed path of motion and back support, allowing for heavy loading and targeted leg development with less spinal stabilization required than free-weight squats.
Since the Hack Squat allows for high mechanical tension without the balance demands of free weights, it is easy to accumulate significant fatigue. Our AI analyzes your recovery metrics and recent training volume to prescribe the optimal weight and rep range, ensuring you stimulate growth without overtraining. Additionally, by comparing your RPE and weight trends over time, the app can detect if your leg strength is plateauing and suggest intensity adjustments or periodization changes to break through sticking points.
Form Cues
- Place your feet shoulder-width apart on the platform
- Keep your lower back flat against the back pad at all times
- Lower the weight until your thighs are at least parallel to the platform
- Drive through your heels and mid-foot to return to the start
- Keep your knees aligned with your toes throughout the movement
- Don't let your heels lift off the platform
- Don't allow your knees to cave inward
- Don't lock your knees forcefully at the top of the movement
- Don't round your lower back at the bottom of the squat
- Don't use momentum to bounce out of the bottom position
Common Mistakes
- Cutting the range of motion short
- Placing feet too high or too low on the platform
- Lifting heels during the descent
- Letting knees collapse inward (valgus)
- Rounding the lumbar spine
Muscles Worked
This exercise is a powerhouse for the quadriceps, placing significant tension on the vastus lateralis, medialis, and rectus femoris due to the fixed back angle. While the glutes and hamstrings assist in hip extension, the machine's design minimizes hip hinge mechanics, making the quads the primary driver of the movement.
Primary
Secondary
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