Gym machines can range from the extremely useful to a complete waste of your time.

It’s not always easy to see the difference and we’ve criticized machines a lot in the past for not being nearly as functional or as effective as free weights, but they’re not all bad. In fact, if you suffer from joint pain, are recovering from an injury, or just feel as if you need a break from free weights, some machines could do you good.

Here are a few of our favorite options:

NAUTILUS PULLOVER

It simulates a pulling movement like the chinup but also provides constant tension in the pullover’s contracted position—something you can’t achieve with free weights. This builds your lats so your body’s V-taper looks wider from the front.

 SUPINE WEIGHTED CRUNCHES

If you’re already doing crunches, this is a good way to comfortably (and easily) bump up the resistance. You shouldn’t depend on it, but rotated in and out of your ab workouts, it can make for an excellent change of pace—and a great six-pack.

SEATED TRICEPS EXTENSION

This apparatus forces you to fix your upper arm on a pad, making the lift stricter and more effective. Some manufacturers make an isolateral version that lets you work one arm at a time.

PREACHER CURL

The advantage over free-weight preachers is that a good machine provides continued resistance at the top of the lift. Some, like Strive machines, also allow you to shift the path of resistance, providing extra stress at the top, middle, and bottom of the lift.

ISOLATERAL LATERAL RAISE MACHINE

This classic lets you work the shoulders one at a time, mimicking dumbbells, only more comfortably. It also provides a unique stress to the middle head of the deltoid, which helps to widen your shoulders.

HAMMER STRENGTH ISOLATERAL CHEST PRESS

A favorite even among the most die-hard free-weight lifters, it allows each arm to work independently. This makes it closer to dumbbell pressing, and provides a different way to work the chest.

BY TOM VENUTO