Many of us forget to workout our back torso muscles, which can result in back or lower back pain - especially if you sit all day. Most gyms have a tool to help you accomplish a stronger lower back.
Hyperextension Bench/45 Degree Angle Hyperextension Bench
Area of Body it Works: Lower back (erector spinae)
Also works: Hamstrings
Why: For a strong back (which helps build strong abs) -- It also helps posture
How: Position yourself onto the leg and waist pad, so that your upper thighs are on the pad, and your waist is just above the pad. You should still have free range of motion at your waist. Brace the backs of your ankles under the leg restraints at the back (bottom if it's a 45 degree angle bench). Cross your arms over your chest. Lower your waist as far as is comfortable towards the floor. Inhale as you lower yourself towards the floor. Exhale as you bring your torso back up, until you are as high as you can go (at least until your body is parallel with your legs) but do not push yourself past the level you are comfortable with. Do not swing or bounce during the movement at any point.
Fit's Tip: It is common for people to hold a weight to their chest to increase the resistance, but make sure you have proper technique and form down before attempting this as it can strain your back and lead to injury.