"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." THE BACK extension, that time-tested move for building back strength, has been around the block. But here ...

Instead of using a back extension machine, try using the 45-degree back extension machine. This piece of equipment helps angle your body as you stand in it with straight legs, allowing you to bend ...

Add Yahoo as a preferred source to see more of our stories on Google. Forget the crowded squat rack—trainers say the back extension machine might be the stealth weapon for building stronger glutes, ...