As a fitness girlie with a particularly large bust, finding sports bras can feel like a sport in itself. Every few years, I wear out the ones I own, hunt high and low to find a style I like, buy several, and wear them into the ground—then the cycle repeats itself. It’s always been a particularly frustrating part of shopping for me and my 38DDs (DDD, depending on the brand).
Recently, I found myself once again on the hunt for my next emotional support bra. This time, I decided to try my luck with the Women’s Health 2026 Fitness Award winner and best sports bra overall: the On Performance Flex Bra. Here are my honest thoughts.
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Pros
- Adjustable straps
- Quick-dry material
- Supportive and comfortable
Cons
- Not inclusive sizing
| Colors | 9 |
| Sizes | XXS—XL |
| Support | Medium |
How I Tested the On Performance Flex Bra
As a fitness editor and trainer, I’m constantly changing up my workouts. I tested this bra during heavy strength-training sessions, runs, and some athletic conditioning workouts including box jumps, kettlebell swings, and hurdle bounds. I wore it to coach some of my strength classes, and I also ran some errands around town with it to see how it handled everyday activities.
I Love the Adjustable Straps.
One of the biggest advantages of this bra is the adjustable straps. For high-impact activities, like running and athletic conditioning, I could tighten it up for extra support. When I was only lifting or running errands, I could loosen it a bit to give myself some more flexibility and comfort. The best part: the straps stay put no matter what you’re doing—no loosening during jumps or runs.
My only complaint about the fit of this bra is that it runs a bit tight around the ribcage. I have a particularly wide ribcage—again, I’m roughly a 38DD—and the underband was a bit snug in the size XL, the largest size they offer. It wasn’t so unbearable that I couldn’t wear it for long stints of time, and the fabric’s stretch definitely helped. Still, I felt some relief taking it off at the end of the day.
It Has a Comfortable Cut.
One complaint I often have with sports bras for larger busts is that they tend to have super restrictive necklines. Where they score points for proper coverage and avoiding wardrobe malfunctions mid-workout, they lack in comfort. Those ultra-high necklines often feel super limiting during upper body workouts and can dig into my shoulders or underarms.
The On Performance Flex Bra provides enough coverage and makes everything feel secure without feeling like it’s closing in around my neck. I also appreciate the lower scoop and cutout in the back, which makes the bra feel more relaxed (and stylish!) for everyday wear.
It also has built-in padding, which is a huge plus. You don’t have to worry about it shifting on you mid-workout or it scrunching up in the laundry. It keeps its shape after several washes and wears.
It’s Breathable.
This bra is made of a combination of quick-drying polyester and super-stretchy elastane, so it feels performance-ready. It also has mesh paneling in the back of the bra, making it super breathable and airy, which I appreciate when working out at a high intensity.
That said, the fabric isn’t particularly soft. It feels a bit more like performance, quick-dry material. It’s not itchy or uncomfortable; it just doesn’t exactly have the same feel as a pair of leggings might. So if you prefer a smooth, buttery texture from your activewear, know you won’t find it here. But if you prioritize function over feel like me, the material dries quickly and stays relatively cool—even during the sweatiest workouts.
Final Verdict: Should You Buy the On Performance Flex Bra?
For me, the Performance Flex Bra’s only major con is the limited size range. In a perfect world, I would go up just one more size and not deal with the tightness of the underband. If you have a ribcage larger than 38 inches, this might not be the bra for you.
If it is available in your size, I highly recommend this bra for just about any workout. The adjustable straps let you customize the level of support, while the breathable, quick-drying fabric stands up to even the sweatiest sessions. It also provides plenty of coverage without restricting any of my workouts.
Needless to say, I think I just found my new go-to sports bra.
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Cori Ritchey, C.S.C.S., is the fitness editor at Women's Health, as well as a certified strength and condition coach and group fitness instructor. She’s reported on topics regarding health, nutrition, mental health, fitness, sex, and relationships for several years. You can find more of her work in Men’s Health, HealthCentral, Livestrong, Self, and others.
Shannen Zitz is the Associate Style & Reviews Editor at Women's Health, where she covers all-things sneakers and activewear. Previously, she was an assistant editor at Prevention. Shannen graduated from the State University of New York at Cortland with a bachelor's degree in English. If she’s not reading or writing, you can probably find her frequenting the skincare and makeup forums on Reddit or hogging the squat rack at the gym.