Certain exercises are pretty much useless or potentially dangerous, yet many women keep doing them because they’re misinformed about the benefits (or lack thereof), says Kelly Drew, RCEP, an ACSM-registered clinical exercise physiologist based in Indianapolis. Here are 4 you ought to delete from your routine, along with safer, more effective options to try instead.

Skip: Sit-ups

If six-pack abs are your goal, don’t bother. “You cannot spot reduce, meaning just work a certain muscle group to make that area smaller,” says Drew. For a defined midsection, you first need to focus on cardio and proper nutrition to burn fat overall, and then concentrate on core-strengthening exercises—and sit-ups aren’t one of them. If you’re lowering your shoulders to the ground with each rep, it’s a sign that you’re relying on momentum rather than your abdominal muscles.

Try: Planks

Planks strengthen all your different ab muscles, which can help you look more toned as well as lower the risk of developing a back injury. Begin by placing your forearms and elbows on the floor directly below your shoulders. Place your toes on the floor with your body straight, and then lift your body up. Tuck your chin in to keep your head and neck aligned with your spine. (Get a flat belly in just 10 minutes a day with our reader-tested exercise plan!) ​ ​

Skip: Standing side bends

They might seem like a simple way to erase those not-so-loveable love handles, but you’re wasting your time. As with sit-ups, most women rely on momentum to do these, which means you’re not isolating your oblique muscles. Plus, you’re probably bending way too far to the side, which could strain your back, says Drew.

Try: Russian twists

To target your obliques more effectively, sit on the floor with your knees bent and feet flat on the floor while holding a medicine ball in front of you. Lean back slightly until your abs engage, then lift your chest and rotate your torso to the right. Touch the medicine ball to the floor before returning to center (start) position, and then rotate in the opposite direction and touch the ball on the floor to your left. MORE: 9 Proven Ways To Lose Stubborn Belly Fat

Skip: Donkey kicks

If you’re doing donkey kicks—getting on your hands and knees, lifting one leg off the floor with a bent knee, and pushing your heel up toward the ceiling—you’re probably hoping to strengthen your glutes. But it’s easy to do this move incorrectly, says Drew. “Most people use momentum and their lower back muscles instead of isolating the glutes,” she explains. Your lower back remains unsupported, which makes it vulnerable to injury.

Try: Single leg squats

To get a tighter tush—and strengthen all of your leg and core muscles—stand on your right leg and place both arms across your chest. Bend your right knee as you sit back and lower your body down about 6 inches while keeping your hips level. Stand up straight to complete one rep. Repeat several times, then do the same thing while standing on your left leg. MORE: The No Squats Belly, Butt, And Thighs Workout

Skip: Lots of biceps curls with light weights

Is your purse heavier than the free weights you keep reaching for? “Many women use very light weights to reduce arm flab, but these don’t put enough stress on the muscles to produce any significant results,” says Drew.  She explains you need to break down muscle fibers before your body will naturally repair and strengthen them. Meanwhile, the temptation to do tons of reps (it’s so easy!) might cause you to strain and injure your tendons and ligaments.  (See why weight lifting is the best workout if you’re over 40.)

Try: Fewer reps with heavier weights

Less (reps) really is more when it comes to working with free weights. “Using heavier weights is the best way to help tone the arms,” says Drew. The key is to make sure that they’re heavy enough to have an impact: You should start to feel the burn at about 10 reps; if you’re easily cranking out 15 reps, you need to go heavier. (And in case you were wondering, no, lifting heavier weights will not make you big and bulky!)