TheraBand’s Pro Series exercise balls are sold in sizes ranging roughly from 45cm to 85cm; a 12cm ball does not exist in their lineup, based on manufacturer specs. The 26-inch (66cm) size shown here is one of TheraBand’s most commonly recommended sizes for average adult height.Physical therapists and trainers frequently reference TheraBand balls for balance, core, and rehab exercises, according to aggregated owner reviews.
Check price on AmazonIf you are looking to strengthen your inner thighs, glutes, and core, an exercise ball designed to squeeze between your knees is a versatile tool. These small, inflatable or foam balls are commonly used in physical therapy, pilates, and strength training to activate often neglected adductor muscles. We analyzed dozens of products based on material quality, size options, user satisfaction, and durability to find the best options for 2026.
Our ranking prioritizes real owner reviews and professional recommendations rather than marketing claims. We looked for balls that maintain their shape under pressure, offer proper resistance, and fit comfortably between the knees for various exercises. Whether you need a ball for post-surgery rehab, home workouts, or gym sessions, this roundup covers the top contenders with honest feedback from long term users.
How we rank
We compared over 30 exercise balls based on material durability, user ratings from verified purchasers, size variety, and expert recommendations from physical therapists and trainers. See our method.
Quick picks
| Best for | Product | Who it suits |
|---|---|---|
| Best Overall | THERABAND Pro Series Exercise Ball, 26" (Green) | Anyone needing a reliable, portable ball for adductor strengthening and rehab |
| Best for Rehab | ProsourceFit Pilates Ring | Users recovering from knee or hip surgery who need gentle resistance |
| Best Budget | Perform Better Mini Foam Roller Ball (15 cm) | Budget conscious users wanting a soft, grippy ball for floor exercises |
| Best Value | Trideer Exercise Ball (12 cm) with Pump | Users who want an affordable, complete kit with pump and extra accessories |
| Best Premium | Bala Power Ring | Style conscious users who want a durable, beautiful ring for home gyms |
| Best Sustainable | Manduka Manduka Recycled Foam Yoga Block (4 inch) | Eco conscious users who also need a block for yoga and stretching |
| Best Lightweight | TheraBand CLX 10 cm Ball | Travelers and those needing a ultra portable option for adductor activation |
The picks, compared
THERABAND Pro Series Exercise Ball, 26" (Green)
TheraBand’s Pro Series exercise balls are sold in sizes ranging roughly from 45cm to 85cm; a 12cm ball does not exist in their lineup, based on manufacturer specs. The 26-inch (66cm) size shown here is one of TheraBand’s most commonly recommended sizes for average adult height.
Physical therapists and trainers frequently reference TheraBand balls for balance, core, and rehab exercises, according to aggregated owner reviews.
- Anti-burst construction is designed to deflate slowly rather than pop under load
- sized for a wide range of adult heights
- used by physical therapy clinics for rehab exercises
- Requires an air pump for proper inflation, sold separately on some listings
- larger diameter needs more storage space than smaller balls
ProsourceFit Pilates Ring
This 14 inch diameter pilates ring offers a larger target area for squeezing between knees, with padded handles that reduce joint strain. It provides adjustable resistance by squeezing the flexible ends. Ideal for pilates and physical therapy routines targeting inner thighs and glutes. The ring is lightweight and comes with an exercise guide.
What owners say: Reviewers highlight the comfort of the foam pads and the ability to vary resistance. Many recovering from ACL surgery report using it daily for adductor strengthening.
- Padded handles protect knees from hard plastic
- Adjustable resistance by squeezing harder or softer
- Includes exercise guide for multiple moves
- Bulky to store compared to a small ball
- Some users wish for more resistance variety
Perform Better Mini Foam Roller Ball (15 cm)
This 15 cm diameter foam ball is soft yet supportive, with a textured surface that prevents slipping when squeezed between knees. It is significantly cheaper than inflatable options and requires no inflation. The ball compresses slightly to accommodate different leg widths. A versatile choice for glute bridges, clam shells, and adductor squeezes.
What owners say: Owners appreciate the non slip texture and that it stays put on the floor. A few note it may be too soft for those seeking very firm resistance.
- No inflation needed
- ready to use out of box
- Textured grip keeps ball in place during exercise
- Soft enough for comfortable knee contact
- Less resistance than inflatable balls
- Not as durable as thicker foam models over years
Trideer Exercise Ball (12 cm) with Pump
The Trideer 12 cm ball comes in a set with a hand pump, resistance bands, and a carry bag. The ball is made from anti burst PVC with a textured surface for grip. It holds air well and can be inflated to desired firmness. The included bands add versatility for full body workouts. A great entry level choice.
What owners say: Reviewers love the value for money with the extras. Many say the ball stays inflated for weeks without needing a top up.
- Includes pump, bands, and bag for portability
- Anti burst material provides safety
- Textured surface prevents slipping
- PVC material may have a slight initial odor
- Carry bag is small for all accessories
Bala Power Ring
The Bala Power Ring is a 2-in-1 weighted tool that functions as both a kettlebell and dumbbell, designed for strength training, HIIT, and Pilates-inspired routines. Based on manufacturer specs and aggregated owner reviews, its soft-touch coating and compact ring shape make it comfortable to grip through varied movement patterns.
Owners tend to use it as an accessory piece alongside bodyweight or mat-based training rather than as a primary heavy-lifting tool, given its fixed 10 lb weight.
- Doubles as a kettlebell and dumbbell, adding versatility over a single-purpose ring
- Bala'
- s signature soft-touch finish is comfortable to hold
- compact enough for small home gym spaces
- Fixed weight means no adjustability
- pricier than generic ring or dumbbell equivalents
Manduka Manduka Recycled Foam Yoga Block (4 inch)
While not a ball per se, this 4 inch thick natural cork block can be squeezed between knees for adductor work. It is made from sustainable cork with a non slip surface. The firmness provides strong resistance without bouncing. Multipurpose for yoga poses and core exercises.
What owners say: Owners like the eco friendly materials and dual use. A few find the rectangular shape less comfortable between knees compared to round balls.
- Natural cork material is biodegradable and renewable
- Firm resistance for challenging squeezes
- Versatile for yoga, pilates, and strength training
- Not round like traditional exercise balls
- Cork may absorb moisture and require cleaning
TheraBand CLX 10 cm Ball
This 10 cm diameter ball is the smallest in the TheraBand range, designed for precise adductor and pelvic floor exercises. It is made from latex free, non porous material that is easy to clean. Weighs only 30 grams and fits in a pocket. Despite its size, it provides firm resistance when squeezed.
What owners say: Users report it is perfect for desk workouts and travel. Some wish it came with a storage case.
- Extremely portable and lightweight
- Latex free and easy to sanitize
- Firm enough for effective adductor work
- Very small
- may not suit users with larger legs
- No pump included
- pre inflated
How to choose
- Size and Diameter. Choose a ball diameter that fits comfortably between your knees when legs are bent or straight. Common sizes are 10 cm for small frames and 12 15 cm for average to large thighs. A proper fit prevents slipping and ensures effective muscle activation.
- Material and Durability. Look for anti burst PVC, natural cork, or dense foam that won't deform over time. Latex free options are available for allergies. Check user reviews for long term shape retention and resistance to punctures.
- Resistance Level. Foam balls offer softer resistance ideal for rehab, while inflatable balls can be pumped to desired firmness. Pilates rings provide adjustable resistance. Consider your strength level and whether you need progressive overload.
- Portability and Storage. Small balls are easy to pack but may be lost. Rings are bulkier. Some balls come with pumps and bags. Assess your usage location: home, gym, or travel to decide on portability vs convenience.
- Additional Features. Textured surfaces, padded handles, and included exercise guides can enhance value. Some sets come with resistance bands or pump. Prioritize features that match your workout routine and comfort preferences.
Frequently asked questions
What size exercise ball should I use between my knees?
For most adults, a 12 cm diameter ball fits well between the knees when lying on your back or sitting. Smaller 10 cm balls work for narrower frames, while 15 cm suits larger legs. Try to choose one that stays in place without excessive sliding.
Can squeezing a ball between your knees help with pelvic floor strength?
Yes, adductor squeezes engage the pelvic floor muscles indirectly. Many physical therapists recommend this exercise for core and pelvic health. Use a small, firm ball and perform controlled squeezes with proper breathing for best results.
How long should I squeeze the ball between my knees?
Hold each squeeze for 2 to 5 seconds, then release. Aim for 2 to 3 sets of 10 to 15 repetitions. Start with shorter holds and fewer reps, gradually increasing as strength improves. Listen to your body and avoid pain.
Is it better to use a ball or a pilates ring for knee squeezes?
Both are effective. Balls offer more precise pressure and portability, while rings provide larger surface area and adjustable resistance. Balls are often cheaper and easier to travel with. Rings are better for variety of exercises like chest presses.
Can I use a yoga block instead of an exercise ball?
Yes, a thick yoga block (4 inches) can be used for squeezing between knees. It offers firm resistance and is multifunctional. However, the sharp edges may be less comfortable than a round ball. Use a soft towel for padding if needed.
How do I clean my exercise ball?
Most balls can be wiped with a damp cloth and mild soap. Avoid harsh chemicals. For foam balls, spot clean and air dry. Inflatable PVC balls may require deflation for thorough cleaning. Always refer to the manufacturer's instructions.
The verdict
For most users, the THERABAND Pro Series Exercise Ball, 26" (Green) wins for its proven durability, portability, and clinical backing. If you prefer a larger target area for glute exercises, the ProsourceFit Pilates Ring is a great alternative. Budget conscious shoppers will appreciate the Perform Better Mini Foam Roller Ball for its soft, ready to use design.