If you’re hitting up social media for ideas on how to mix it up, workout-wise—or just to get a jolt of good ol’ inspo—you may be finding more than you bargained for. On the one hand, there are a lot of Insta-famous trainers who definitely motivate you to get your heart pumping. But along with that, you can also get a feed full of impossible-seeming (but wildly impressive-looking) exercises.

“When you see a move that makes your jaw drop, that’s probably a move you shouldn’t be doing,” says Kira Stokes, the veteran celeb trainer who created the Stoked Method.

“When you see a move that makes your jaw drop—that’s probably a move you shouldn’t be doing.”

They’re often referred to as “trainer tricks,” and Stokes says that if they come with a “don’t try this at home” warning (like doing a box jump onto the legs of someone performing a wall sit), the risk usually outweighs the reward. “Be smart about the accounts you follow for information,” Stokes advises. “There’s a difference between entertainment and information.”

At the same time, there are some circuit stalwarts that aren’t dangerous at all—but IRL trainers will tell you they’re not worth your time if you’re trying to get the most out of every sweat-drenched minute in the gym. So in the name of safety, efficiency, and effectiveness, which exercises do top instructors say you should skip?

We asked 4 pros to share the moves you’ll never catch them doing at the gym—and what you should replace them with instead.

1. Partner leg throws

“Everything can go wrong with these,” Stokes says of the move where you’re lying on your back with your legs straight up in the air, and your partner grabs your feet and “throws” your legs down.

“It becomes like a battle of wills. When your job is to throw someone’s legs down, it’s so difficult to know the exact right amount of force to put into it. And for the person on the floor, it’s so challenging for the low back to stay anchored to the ground when there’s such a strong force throwing the legs down,” she says.

The result? Your back will probably arch to keep your legs from hitting the floor, which could increase your risk of back injury—especially as you do more reps.

What to do instead: “If you’re trying to target the entire rectus abdominis, do hanging leg raises instead,” says Stokes. “It may not be a big powerful movement like partner leg throws, but you’re controlling your own power and timing instead of relying on somebody else to provide the force.”

2. Behind-the-neck or rear lat pulldowns

“I see so many people who are new to training doing these, and the risk for injury is just too high” says Dara Hartman, trainer at The DogPound in New York City. “There’s a tendency to protrude the neck to allow space for the bar to move behind the head, and there’s danger in externally rotating the shoulder a little too much, which can cause pressure on the joint, resulting in strain or injury.”

What to do instead: “To work my lats and back, I love utilizing resistance bands,” says Hartman. “I’d do banded lat pull-downs—those are front pull-downs—or band-assisted pull-ups instead.”

3. Standard crunches

“You’ll never catch me doing standard crunches because they’re relatively ineffective compared to other movements,” says Jess Sims, trainer at NYC’s Fhitting Room. “They place a lot of stress on the lower back from the constant spinal flexion, or rounding of the back, and they only focus on one section of your core and ignore other really important areas like the obliques and lower back.”

What to do instead: First, check your form. “An upgrade would be the hollow hold, because it strengthens your entire core—the upper abdominals, lower abdominal, obliques, and lower back—so you get much more out of this exercise than traditional crunches,” says Sims. “Or you could do bicycle crunches as a twist on the hollow hold. The bicycle crunch is much more effective at engaging your obliques and lower abs than a traditional crunch.”

4. Side crunches

“I find side crunches so uninspiring,” says Erika Hammond, a founding trainer at Rumble Boxing in NYC. “If I’m lying on a mat curled up like that, I’m probably going to sleep! They’re not nearly as effective as other oblique exercises.”

What to do instead: “A side plank crunch or side plank dips are better options,” says Hammond. “They’ll awaken and use many more muscles at once.”

If you’re all about making your sweat sesh minutes count, this new at-home bike takes Netflix-and-spin to the next level. Or get in a good cathartic cry with your yoga flow with this pose.