My gym got a new back extension machine recently and it is horrible. It's designed for someone much smaller than me, the angles are all wrong, and I find it very difficult to isolate the right muscles (I end up working my legs instead).
Is there a way I can target those muscles and do weight training using other equipment available at the gym?
I had been lifting > 100 pounds with the old back extension machine.
Supermans will work your lower back without the need for ill fitting machines.
So does the plank.