The surefire way to make any exercise move harder? Do it on a stability ball. Stability ball exercises are a $20 way to take your floor routine to the next level, adding a bonus level of dynamism to your workout. “Adding a stability ball to an exercise can take a basic move from ‘I can do this in my sleep,’ to ‘this is the most challenging thing I have ever done,’” says Tiffani Robbins, director of the sculpt program at NYC’s Fithouse.

This happens because your core has to fire up to do work in addition to whatever other exercise you’re doing, and that means a major payoff. “Stability balls challenge both balance and stability, which are a part of functional training that should not be overlooked since they are a huge aspect of our daily lives,” Robbins tells me. “Working with any type of unstable surface or object will automatically recruit additional muscles when performing certain moves. When adding a stability ball to an exercise, your core will have to engage more to find balance than when you do the the move without it.”

That added muscular engagement ultimately has other positive side effects, too. “There are two standout benefits that come to mind when I think of the stability ball: Improved spinal stabilization and increased use of muscle fibers during a given exercise,” explains Nicole Petitto, senior manager of group fitness and co-creator of the Pilates Remix class at Equinox. “The stability ball is also ideal for increasing core strength, balance, and coordination.”

What size stability ball should I use?

When it comes to picking out which stability ball to use, size does matter: If you’re between 4.5- to 5-feet tall, use a 45-centimeter ball, if you’re between 5- to 6-feet tall, use a 55-centimeter ball, and if you’re over 6-feet tall, use a 65- to 75-centimeter ball. An easy way to test it, says Robbins, is to sit on a ball with your feet on the floor, and make sure your knees are out at 90-degrees.

Another thing to assess? Make sure to check your equipment for over-inflation, punctures, or worn areas, so you can be sure it will be able to function properly and support your bodyweight (instead of collapsing or falling out from under you). “When working with a stability ball, you may notice a heightened awareness of your posture, a deeper connection and engagement to the core, and the identification of where potential muscle imbalances may lie within the body,” says Petitto. “Aside from providing a greater level of intensity to a given exercise, the stability ball also offers immediate feedback to the body that can improve your alignment and the proper execution of a movement pattern.”

You can up the ante on just about any regular ole exercise by turning it into a stability ball exercise. For example, Robbins loves to add them to abdominal work, while Petitto makes them a part of her Pilates routine. A few pro tips, no matter how you decide to use them: “I usually program movements to be performed in a slower and more controlled manner to ensure the level of safety of an exercise,” says Petitto, noting that anyone just getting started with their stability ball routines should “begin with the most regressed version of an exercise and slowly build to find the level of challenge that is right.”

If you’ve got certain medical conditions like balance disorders, dizziness, osteoporosis, or epilepsy, you may want to be careful about introducing a stability ball into your regimen.  Even if you don’t have any of those conditions, starting your stability ball exercises with a personal trainer can help (or at least, have someone there to spot you for the first few times you try them), and be sure to only bring a move onto the ball once you’ve mastered it on the floor.

“A lot of time people hate stability balls because they think they can’t find their balance, which is obviously the point,” says Amanda Kloots, creator of AK! Body. As anyone who has ever tried any sort of a workout on top of a stability ball knows, balancing makes things a whole lot harder, and of course, a whole lot more effective. With all of that in mind, here are 16 stability ball exercises to make your mat moves more effective (and interesting) than usual.

Full body

Full body ball workout: This one’s a killer, care of Kloots. Start standing up with the ball at your feet, and come forward climbing over it. Walk your hands out into a plank until your feet reach the ball, flexing them to keep the ball in place. “Hold both knees together, squeezing your inner thighs and your glutes, cupping the ball with your flexed feet,” says Kloots. Roll both knees into your chest with the ball held under your feet, then stretch them back out into a plank, “like a caterpillar,” Kloots explains.

Next, stand up, hold the ball above your head, and do 16 jumping jacks, bringing the ball up and down as you jump. Still standing with the ball over your head, bring your right knee up 16 times, and equal out on the left side. “It’s a great way to also work your heart, because any time you go down and up, you’re maximizing cardio,” says Kloots. “Then, when you hold the ball and you do those jumping jacks and then those leg-knee pulls on the right and left, you can feel your arms, and they will burn because that ball gets heavy, and you’re not used to holding something above your head like that. So it’s a great way to incorporate the stability ball into a cardio exercise, but also rolling yourself out working on stability and control of your abs.”  Um, ouch. 

Core

Stability ball plank knee tucks and plank to pike: Place your hands on the floor and your ankles on top of the stability ball in a plank position. Keeping your balance, carefully draw your knees into your chest by slightly lifting your hips and rolling the ball forward, then return to your starting plank position. Keeping your legs straight, pull your hips up in the air into a pike position, and then again, go back to your beginning plank position. Keep your shoulders over your hands and your core engaged the entire time.

Stability ball oblique crunches: Stand with your feet wide and knees soft while holding the ball over your head (the straighter the arms, the harder the movement). Keeping your shoulders and hips facing frontwards, hinge to one side, keeping the ball in line with your head. Slowly lift back to standing by engaging the opposite side of your core (AKA your obliques), and repeat on the other side.

Stability ball leg lift ball pass: Lay on your back and place the stability ball between your ankles while your legs are raised to 90 degrees. Keeping your lower back anchored to the floor, lower your legs to 45 degrees (or lower, if you can) while reaching arms behind you. Return to starting position and grab the ball in your hands. Repeat the movement, but this time you’ll be holding the ball in your hands. Continue moving by passing the ball back and forth from your hands to your feet.

Ballers: This one is an AKT favorite (yes, Anna Kaiser herself) that Kelly Ripa swears by for stronger abs. Start in a push-up position with your shins resting on the exercise ball, then tuck your knees to roll the ball in toward your chest while making sure to keep your lower back straight. Pause briefly, then untuck your knees and roll the ball back to its starting point, and repeat 30 times. To make things even more burn-inducing, add a push-up in the middle of the move.

Stability ball planks: A plank, but make it damn near impossible. Place your hands on the floor and your legs on top of the ball (anywhere from shins to top of feet, noting that the farther your hands are from the ball, the more difficult the move will be), and try to keep your hips in line with shoulders, and shoulders stacked over hands. Keep your abs engaged, and hold this position for as long as you feel stable.

Back extensions: Position your torso and chest on the top of the ball, and lift and lower your upper body as a “great way to strengthen the postural muscles, access the posterior chain and target the core,” says Petitto.

Mountain climbers: Lock into your stability ball plank position with your feet hip-width distance apart (it gets really, really hard if you put them together), and slowly bring one knee forward until it touches your elbow. Bring it back to start, and repeat on the other side. It’s worth noting that these should be done much, much more slowly than the mountain climbers you usually do on the floor, but combined with the balancing challenge, they will definitely have you feeling the burn in a similarly intense way.

Stability ball jackknives: One of fitness influencer Cristina Capron‘s favorite moves? The stability ball jackknife. Start with the ball underneath your toes and your hands on the floor with your core tight in a raised plank position. Keep your spine neutral, and bend the hips and knees to bring the feet closer to the hands. Pause at the center, then push your feet back into the starting position.

Plank Circles: In a forearm plank pose with your arms on top of the ball and hands clasped, roll the ball in slow circles underneath your chest to strengthen stability. Switch directions to give your body a full range of motion.

Glutes

Stability ball split squats: Place your front foot firmly on the floor, and bend your other leg to 90 degrees to place the top of the foot on the ball behind you. Slowly bend the front leg—keeping the weight in your heel—as you extend your back leg, rolling the ball backwards, hinging forward at the hips slightly to counter balance your weight. Slowly reverse the movement to return to standing position.

Shoulder bridge: Fire up your lower body with this butt burner. “This is a great way to immediately connect with the hamstrings and glutes, offer an increased range of motion for the spine and feel an opening through the front of the hips,” says Pettito. Lie on your back with straight legs and the ball underneath your heels. Slowly roll the ball toward your butt, bending your knees and lifting your glutes in the process. Move slowly, then return the ball to the starting point and repeat.

Flutter kicks: On your stomach, roll the ball underneath your belly button with your hands on the ground, feet extended behind you, and abs tight. Flutter kick your feet out behind you, and hold one leg at a slight rotation with every third flutter, alternating legs every time.

Stability ball wall squats: Stand a few feet away from a wall with your back to it. Place the ball behind you, essentially sandwiching it (gently!) between your back and the wall, then walk your feet out a few inches in front of you. Slowly squat down as if you were sliding your back down the wall, and lower to a comfortable level—just make sure your knees don’t extend out past your toes. Hold the squat at the bottom for a few seconds. Press back up, engaging your thighs and glutes.

Arms

Push-ups: With your hands on the floor and your feet on the stability ball, bend your arms into a push-up and keep your back straight and core tight, the same way you would while doing push-ups on the floor. Extend your arms and repeat for as many reps as you can.

Tricep extensions: With your hands on the ball and feet extended on the floor behind you, bend your elbows and make sure your arms are pulled in tightly to your ribs. Push up and pause at the top, then lower back into the tight arms position, making sure your triceps are engaged.

Bicep curls: Kneel behind the ball and rest your right upper arm on top of it while holding a dumbbell of your choice in your left. Raise and lower with your bicep engaged, and work with the ball to keep your balance. Do one arm at a time and switch.

Shoulders

Stability ball shoulder press: Sit tall on the ball with a pair of dumbbells, and bend your arms, lifting them to shoulder height so that the weights are next to (or in line with) your face. Rotate your arms so your palms are facing out, then raise your arms all the way over your head to bring the weights almost to touch at the top. Hold at the top before returning to the starting point, and repeat. “This will help build your upper body strength and core stability at the same time,” says Aaptiv master trainer Rochelle Moncourtois.

Stability ball shoulder blade squeeze: “This move helps improve posture, which can help offset upper back pain,” says Moncourtois. Sitting tall on the ball, relax your arms down by your sides or at a 90-degree angle with your palms facing forward or up. Gently squeeze your shoulder blades together, hold for five to 10 seconds and release.

Getting a full-body workout doesn’t require going to the gym: Here are 11 ways to get Michelle Obama-level arms without weights, and exactly how to master the plank to your strongest core ever.