Like bad 80’s shoulder pads and frosted tips, some exercises go out of style—and for good reason. Here are the exercises trainers would never recommend you do nowadays, and their safer, more-effective alternatives.

STOMACH SLAPS

Some trainers thought that hitting the stomach of someone performing crunches would cause them to brace their core, creating a tighter muscle contraction.

The idea was that this would lead to better-looking abs, but the only people who might find it useful are MMA fighters because they actually take hits in the breadbasket, says BJ Gaddour, C.S.C.S., Men’s Health fitness director and creator of Bodyweight Cardio Burners. (available as a DVD with the June issue of Men’s Health)

Better option: The hollow-body hold

Try the hollow-body hold if you want a serious punch to the gut—in a good way.

“It’s a stability exercise used by elite gymnasts to build extreme core strength,” says Gaddour. And it works. After all, how many gymnasts have you seen without high-definition abs?

Do it: Lie on your back on the floor or a mat with your legs straight and your arms down by your side. Bend your knees and lift your feet until your thighs are perpendicular to the floor.

At the same time, contract your abs, raise your head and shoulders blades so they no longer touch the floor, and lift your hands a couple of inches so they hover next to your body.

To progress the movement, straighten out your legs so they are a few inches above the ground. Your body should form one long line.

To take it up another level, reach your arms over your head so your body forms a banana shape. Hold this position.

BEHIND-THE-NECK PULLDOWN

The movement was originally used to zero in on the upper-back and shoulders. But trainers soon found out that the exercise puts your shoulder joints and upper spine in an awkward position, increasing your potential of injury to those areas.

“The risk definitely doesn’t outweigh the benefit,” says Brad Schoenfeld, Ph.D., C.S.C.S.

Better option: Front pulldown

You’ll minimize your injury risk, and maximize your muscle activation.

Do it: Sit down in a lat pulldown station and grab the bar with an overhand grip that’s just beyond shoulder width. Without moving your torso, pull the bar down to your chest as you continue to squeeze your shoulder blades. Pause, then slowly return to the starting position.

BARBELL TWIST

“Apparently, loading a barbell on your shoulders and twisting back and forth was supposed to work your obliques,” says Tony Gentilcore, C.S.C.S., co-owner of Cressey Performance in Hudson, Massachusetts. But it’s actually more likely to damage your spine or knock out another gym patron, he says.

While your obliques play a role in bending and twisting your torso, they actually work harder when you try to resist movement to protect your spine—so that’s how you should work them.

Better option: Band-resisted anti-rotational press

Your obliques won’t twist during the band-resisted anti-rotational press. Instead, they must keep your torso from rotating against the pull of the band.  

Do it: Grab a continuous-loop exercise band and tie it around a vertical post so it’s just below shoulder height. Stand with your feet shoulder-width apart and the right side of your body facing the post.

Pull the band in front of you so it’s even with the middle of your chest. Holding it in both hands, take a step or two away from the post to create more tension in the band.

Extend your arms out in front of you, pressing the band away from your body. Pause, and then reverse the movement to return to the starting position.