The best exercise balls (and why you need one): Bosu, Theraband, Gaiam and more

Size options: 45 cm, 55 cm, 65 cm, 75 cm, 85 cm | Burst-resistant: Yes | Weight capacity: 1,000 lbs., static-tested to 600 lbs. | Colors: Up to 5, depending on size | Materials: PVC, phthalate-free, free of heavy metals, latex-free | Special features: Full-size exercise poster, 0.08-inch thick walls | Also included: Adapter for bike pump

This trusty Theraband Pro ball passed all our tests with flying colors. The durable, nontoxic 0.08-inch skin boasts roughly twice the thickness of most balls we tested. This also made it a bit tougher to pump initially, but an air compressor did the trick. Should it get punctured, it will kindly deflate slowly. The raised concentric rings help with grip, and the surface is just sticky enough to lessen slippage during exercise without feeling icky. The included full-size poster with photos of exercises provides immediate inspo. There are sizes to suit just about everyone, from 4'7" to 6'9" and up.

Both Pilates instructors we consulted are fans. Stamos says, "My preference is the TheraBand Pro Series ball as it’s constructed from nontoxic materials, is burst-proof and it’s made for physical therapists." Anna Clark, owner and master trainer at Nexa Studios in New York City, adds: "They have decades in the game and have built high-quality equipment people can trust." 

Indeed, TheraBand was started over 40 years ago by a pair of clinicians with the intention of helping patients recover and has become a go-to brand for many health and fitness pros.

Size options: 55 cm, 65 cm | Burst-resistant: Yes | Weight capacity: 1,000 lbs. | Colors: 2 | Materials: PVC | Special features: Manual via QR code; one-year warranty Also included: Hand pump, two plugs

This tough Bosu ball is a great tool for intense workouts. During testing, it felt sturdy and very supportive and remained fully inflated. It also stayed cool to the touch, which was not one of our original criteria but totally is now. Ahhh. Despite the smooth skin, I found it to be no more slippery than the other top contenders when put to the sweat test — the subtle added texture at the top helps with grip. Plus, something about the old-school medicine ball look just inspires a Rocky-level workout. 

Made by personal trainers, this is the only U.S.-made ball we tested — or even found. It inflates easily with the hand pump and is burst-resistant up to 1,000 lbs. 

Size options: 65 cm | Burst-resistant: Yes | Weight capacity: 1,000 lbs. | Colors: 1 | Materials: PVC, phthalate-free, free of heavy metals | Special features: Unique wavy and dotted texture Also included: Hand pump, two plugs, plug remover

Of the $20-and-under balls we considered, this Dick's Sporting Goods exclusive performed (and definitely looked) the best. It was simple to inflate, with clear instructions and helpful photos. It held its shape well and stayed fully inflated throughout testing, and the grabby texture helped to prevent slippage during exercise. Aesthetically, the warm, rosy-gray hue and wavy, textured design also caught the trained eye of my French artist friend who dropped by to give the balls a try.

While it's available in only one size, it was just right for my 5'9" frame and is well suited to those a few inches shorter or taller. 

Size options: 55 cm, 65 cm, 75 cm | Burst-resistant: Yes | Weight capacity: Static weight rated to 2,000 lbs. | Colors: Up to 3, depending on size | Materials: Non-phthalate PVC | Special features: Exercises are described in an included booklet, a free DVD featuring fitness educator Brook Benten and on the ball itself plus $1 app | Also included: Foot pump, 2 plugs, plug remover, bicycle pump adapter, measuring tape

Getting started is a breeze with this guy. It pumps up in minutes and displays the proper form for exercises everywhere, including right there on its face. My exercise partner Julie appreciated the rough grippy texture and thinner walls, "It has the best skin," she said, giving it a little squeeze. "The material is better for digging in and finding stability." I agree that it felt less likely to get away from me than the firmer balls when testing new positions.

Newbie ballers should heed the advice of Reginald Cociffi-Pointdujour, PT, DPT: "It is important to use any exercise tool safely and effectively. Always err on the side of caution if you are using any tool that requires you to have balance and trunk stability. If you are unsure about your own abilities, seek consultation with a physical or occupational therapist or with a trained and tested exercise professional."

Size options: 45 cm, 55 cm, 65 cm, 75 cm, 85 cm | Burst-resistant: Yes | Weight capacity: 2,200 lbs.; anti-burst to 330 lbs. | Colors: 6 | Materials: PVC, phthalate-free, BPA-free, free of harmful heavy metals | Also included: Foot pump, two plugs, plug remover, measuring tape

This nontoxic No. 1 bestseller has over 27,600 five-star fans at Amazon — and it lives up to the hype. It twins our winning pick, the TheraBand Pro, in design style, feel and sizing options. In a few ways, this Trideer excelled: It took under five minutes to inflate with the manual foot pump, offers more color options and boasts a higher weight capacity than the Theraband. It did not, however, include exercises or have the time-tested history of the TheraBand brand, and there was a minor visible manufacturing flaw (one of the raised circles was uneven around the plug), which puts the quality into question. Still, it has stayed inflated and held its shape quite well. Plus: Shoppers are loving it.

"This is a fabulous ball!" wrote one physical therapist in their Amazon review. "Very impressed with the quality, price and what's included. Nice to include the pump, though it is quite tedious (got a 'bonus leg workout' inflating it, LOL). Absolutely recommend this product."

Note: While it's priced similarly to the Theraband, we've seen it dramatically discounted during big sale events.

Size options: 55 cm, 65 cm, 75 cm. | Burst-resistant: Yes | Weight capacity: 440 lbs. | Colors: 3 | Materials: PVC, free from lead, cadmium and 10 harmful phthalates | Special features: Pregnancy guide, baby book | Also included: Hand pump, inflator, two plugs

This nontoxic, nonslip birthing ball is dedicated to the mamas for belly, birth and beyond. Its specs are similar to those of Amazon's No. 1 bestseller from Trideer, but it's newer, thicker and comes complete with a memory book, exercise guide and more at no extra cost.

Advanced doula Emily Wannenburg, CEO and founder of 4th Trimester Fitness Method, isn't picky about which exercise ball you choose during pregnancy, but she is such a believer in their benefits that she's created a whole training course on the subject. "In labor, the ball has many benefits," she says. "The ball rocks for back pain. Just sitting on the ball fires the deep core and pelvic stability muscles. In labor, hip circles and clocks are shown to reduce the perception of back labor between 6 and 8 cm. For postpartum, nothing beats small bounces on the ball holding a fussy newborn!" This last sentiment is echoed by Yahoo's Senior Health Writer, Laura Williams, who says she practically lived on a stability ball for the first few months after giving birth to her son — "It was either pacing for hours or bouncing on the stability ball — nothing else seemed to calm his colic," she says. 

Size options: 55 cm, 65 cm, 75 cm, 85 cm, 95 cm | Burst-resistant: Yes | Weight capacity: 2,200 lbs. | Colors: 6 | Materials: PVC, BPA-free, latex-free, phthalate-free and free of heavy metals | Also included: Hand pump, inflator, two plugs

The tallest of the tall and the leggiest of the leggy will appreciate the supersize options available for this heavy-duty orb. The extra large sizes may also come in handy for those who are less flexible. The apparent durability is impressive. The maker notes, "It can withstand up to a 2 cm cut without explosively deflating." Reassuring!

Admittedly, after hours of trying with the hand pump, a bike pump and even an air compressor, I was unable to get it all the way to 95 cm, but it did surpass 85, which is the max for most other brands. 

Size options: 40 cm, 55 cm, 70 cm, 85 cm | Burst resistant: No | Weight capacity: 270 lbs. (tested to 660 lbs.) | Colors: 3 | Materials: PVC, latex-free and phthalate-free, lead-free, BPA-free | Special features: Peanut-shaped | Also included: Extra plugs, pump adapter

This Italian-made inflatable looks, feels and smells like happy childhood memories (perhaps because it's made from the same thick, shiny vinyl as Rody the ride-on horse, who was born in the 1980s), but it's sized for grown-ups. It's an especially good choice for guided use with seniors and for people with balance issues who wish to engage in slow, gentle stretches and bodyweight-only core work. The vinyl is smooth and pleasant to the touch. 

While very thick, it's not anti-burst (there's no U.S. distributor for the burst-resistant version at the moment), so keep your exercise area free of sharp objects and inspect it for damage before every use. For those with balance issues, I'd recommend a spotter or placing it against a wall when first starting out.

"Throughout my career, I have worked with elderly individuals who benefited from balance and stability training," Stamos says. "A favorite beginner exercise for grounding is having the student sit on the ball with feet planted on the floor while I gently push on the ball from different directions. My light pressure on the ball challenges the client to maintain their stability against pressure, which activates core and deeper muscles that can be overridden by larger muscle groups in most traditional exercise modalities. I also love the relaxation that laying the torso over the ball produces, both prone and supine."

Note: I tested the massive red version, but this 70 cm blue or the 55 cm yellow will be much more manageable for most adults. 

Size options: 65 cm diameter. | Burst-resistant: Yes. | Weight capacity: 350 lbs. | Colors: 8 | Materials: Latex-free, "phthalate-compliant" | Special features: QR code with manual, workout videos, downloadable wall charts and more; one-year warranty | Also included: Hand pump

The made-in-the-USA Bosu outshines its half-ball competition when it comes to functionality and quality. Sure, there are other lighter halfsies (this one is 15 lbs) and more affordable options out there, including two that we tried and liked (see "Other products we tested," below). Still, Bosu claims the crown. It's easy to use, durable and reliable — it held air and stayed put during our workouts. Plus, our experts are into it:

"I like Bosu balls a lot for hip and core work," Tresize tells Yahoo Life. "Any exercise performed while standing on a Bosu adds a big balance challenge, and I enjoy crunches and hip thrusts on it as well."

Stamos seconds that: "Bosu balls are fantastic for proprioception and balance. Just standing on them activates muscles to keep you from falling off. After mastering standing on two legs, lifting one leg and balancing is simple but difficult and very effective in energizing the core reflexes. Bird dog [exercise] on the Bosu is excellent for core stability as well as ab work with the half ball under the torso."

Size options: 9 inches. | Burst-resistant: Yes | Weight capacity: 264 lbs. | Colors: 6 | Materials: PVC | Special features: Honeycomb anti-burst material, 9 exercises included | Also included: Straw for inflation, plug

This high-quality, nontoxic 9-incher is our top pick of the minis for core work, pelvic floor work, barre exercises, stretches and restorative poses. It inflates in seconds, holds air well, feels durable and has just the right amount of stickiness. In the roomful of balls, this is the only one that my friend and workout buddy Julie wanted to sneak out with: "This I could use, and it wouldn't take too much space."

Clark says mini balls are a great add: "These much smaller, even more affordable little balls have more application as a tool to pull everything into alignment when you place them in the hands or feet to 'hug the midline' of the body. In the feet or thighs they act much like a ThighMaster while also lining up the leg bones and helping the tracking of the knees during various exercises." 

Stamos chimes in: "Another great use is to place the ball under the pelvis to relax into proper hip alignment. Once aligned well, single and double leg extensions are a wonderful way to strengthen the core."

Size options: 65 cm. | Burst-resistant: Yes. | Weight capacity: 265 lbs. | Colors: 2 | Materials: Cover: Natural cork with leather trim (faux leather available on request); layer: polyester and nylon; inner ball: PVC | Special features: Cork cover, lovely stitching, leather handle. | Also included: Plastic hand pump wrapped in leather.

Want to go all out? This made-in-Poland ball is a stunner with a gold-paint-flecked cork cover that's stitched shut and finished with a fine leather trim and handle (or faux leather, if preferred). In fact, this sphere can do triple duty — as workout hero, bonus seating and art piece. The cover, also available with silver accents, is eco-friendly, durable, nonslip and ready to use without a mat. (Naked vinyl balls don't do well on wood floors or when touching painted surfaces.) 

If this isn't indulgent enough, take a gander at what else this purveyor of handcrafted fitness equipment has to offer — namely, the super-decadent (and even pricier) original Mesna Premium Leather fitness ball. 

Do you need one of these? Probably not. But it's a mighty fine design upgrade for the person who has it all.

Size options: Fits 5' to 5'11", optional extenders available. | Burst-resistant: Yes. | Weight capacity: 300 lbs. | Colors: 1 | Materials: Nylon, steel and PVC (latex-free, 7P-free) | Special features: Casters that lock, removable exercise ball, downloadable chair exercise guide | Also included: Pump, plugs, clear instructions

I'm a wiggly one at work. I've had my share of hip surgeries (four, so far) and spine issues, so being stuck in an office chair all day is frustrating, confining and deeply uncomfortable to me. But Cociffi-Pointdujour warns against substituting an exercise ball alone for your office chair: "It is not a safe alternative to a normal chair and is likely not more useful than regular exercise to achieve improved trunk stability." I'm finding this roll-y ball chair from Gaiam to be a nice hybrid option for part-time seating. It is superior to a ball alone, thanks to wheels that can lock, and when removed from its chassis it's great for midday stretches. There's even a swivel base option for $21 extra.

Unfortunately, what appears to be some semblance of lumbar support is actually not. It's intended only as support to grab onto during stretches, according to Gaiam. (Note: I did try slipping a semi-deflated miniball back there, and it felt nice.) Hopefully lumbar support will be an option in a future model. 

The ball itself is a sister of the one that Clark recommends: "Gaiam has been making bodyweight and calisthenic equipment for decades before the rest, and I will stay loyal to those that have been in the know the longest. They offer great, high-quality equipment across the board."

Size options: 45 cm. | Age recommendation: 5 to 8. | Burst-resistant: Yes. | Weight capacity: 200 lbs. | Colors: 2 | Materials: PVC that's 8P-free and free of heavy metals | Special features: Peanut shape | Also included: Pump

Kids delight at the sight of this bouncy peanut. It carries an age recommendation of 5-7, but I tested it with four kids (ages 5, 7, 8 and 10) who found countless uses, including rocking, rolling, bouncing, squeezing, superhero-ing, lifting, tossing and eventually a bit of sitting. An excellent tool for creative play and gross motor skills, coordination, balance, strength and core stability. Note: Do not stand or kneel on this or any ball.

As a former preschool teacher and creative movement instructor, I can attest that most children will dive headlong onto a big round ball — and go flying. This fun-size option is safer and less stress-inducing for any adults present. My young testers unanimously preferred it to the ball seats with stabilizing feet.