Lying under a Smith machine and pressing the bar up with your feet. A leg press substitute when there's no machine, with the bar path guided by the rails.
Primary muscles
Secondary muscles
This information is general fitness guidance, not medical advice. Stop if you feel pain and consult a qualified professional.
Main muscles working (thicker lines)
Set the Smith bar on the safeties a couple of feet off the floor. Lie on your back underneath it with the middle of both feet on the bar and your knees drawn toward your chest.
Unhook the bar and drive through your feet to press it up.
Extend your hips and knees until the legs are nearly straight, without locking out.
Pause briefly at the top.
Lower the bar under control until your knees come back toward your chest, and repeat.
Breathing: Inhale as you lower, exhale as you press.
Mid-foot on the bar
Lower back stays down
Soft knees at the top
Setting the safeties too low to catch the bar
Feet drifting toward the toes
Hips peeling off the floor at the bottom
Locking the knees out
Set the safeties just below your bottom position and re-hook the bar before moving your feet.
Start light: a slipping foot drops the bar toward you.