Barbell Hack Squat

How to do it

Stand up straight while holding a barbell behind you at arms length and your feet at shoulder width. Tip: A shoulder width grip is best with the palms of your hands facing back. You can use wrist wraps for this exercise for a better grip. This will be your starting position.
While keeping your head and eyes up and back straight, squat until your upper thighs are parallel to the floor. Breathe in as you slowly go down.
Pressing mainly with the heel of the foot and squeezing the thighs, go back up as you breathe out.
Repeat for the recommended amount of repetitions.

What muscles does the Barbell Hack Squat work?: Mainly the quads, with help from the calves, forearms, hamstrings.
What equipment do I need?: Barbell.
Is it good for beginners?: It is rated intermediate level.
How do I track progress on it?: Log each set and beat the weight or reps from last time. Liftrung shows your last set beside the next one and estimates your one-rep max from your sets.

Exercise descriptions: free-exercise-db, public domain.