On
Performance Flex Bra Medium-Impact Support
The On Performance Flex Bra is a medium-impact sports bra designed for running and intense sports, featuring adjustable front straps, a racerback design, and zero clasps or boning. It is made from soft stretch microfibre jersey that wicks moisture, with mesh panels, moulded cups with breathable foam lining, a built-in support band, and reflective details. Available in A-C and D/DD cup versions, it is praised by runners for its chafe-free, seamless fit and adjustable straps.
Size
Specifications
- Material
- Main material: 62% polyamide, 38% spandex; Mesh: 82% recycled polyamide, 18% elastane; Cup lining: 100% recycled polyester; Bottom band: 86% polyamide, 14% spandex; Straps: 72% polyamide, 28% spandex
- Gender
- female
- Age Group
- adult
- Condition
- new
Product Insights
The On Performance Flex Bra Medium-Impact Support delivers mid-run adjustability via front straps and permanently bonded padding that never shifts, ensuring chafing-free comfort across yoga, Pilates, and running, with versatile A-C and D/DD cup sizing—though its medium-impact design may not suffice for high-impact movements.
- Front adjustability
Front-adjustable straps tighten mid-run to maintain support and prevent chafing.
Why this is supported
Runners report that the front-adjustable straps can be tightened on the go as sweat and movement cause slight loosening. As one runner shares,
It has adjustable straps in the front, so as I run and get sweaty, I can tighten it, keeping everything in place.
u/quivera in r/RunNYCAnother runner corroborates that the seamless construction prevents chafing:
Straps are adjustable and it’s overall pretty seamless so no chafing or hot spots on long runs.
u/Snickerfin in r/XXRunningWomen's Health's lead tester also noted that the front adjustability is way easier to adjust than traditional bras. The ability to tighten when sweaty ensures consistent support throughout runs.
- Comfort
Wide adjustable straps prevent shoulder digging and chest gapping vs fixed-strap bras.
Why this is supported
A Women's Health review confirms the wide adjustable straps distribute weight evenly without digging:
The wide adjustable straps are another favorite feature of mine. They distribute weight evenly across my shoulders without digging in or creating pressure points during longer workouts. Even better, the straps adjust from the front so it’s way easier to adjust than traditional bras.
womenshealthmag.comIn contrast, a reviewer of the Lululemon Energy Bra notes a gap in the upper chest during hinging positions:
I do notice a bit of extra space at times, especially in hinging positions or during planks.
thatfitfriend.comThe Flex Bra's front adjustable straps allow a custom fit that eliminates such gapping, providing a secure feel during movement.
- Bonded padding
Pads are permanently bonded, preventing shifting and scrunching after washing.
Why this is supported
Women's Health and product feedback confirm the bonded padding eliminates post-laundry pad trouble. The publication states:
It’s built in—so you never have to deal with shifting, scrunching, or fishing pads out of the laundry
womenshealthmag.com. A reviewer echoes that removable pads are a frustration:
Removable pads are also not my favorite but unfortunately, they’re super common in medium impact bras.
inspiredplum.com. The padding design contributed to the bra being named Women's Health's Best Overall Sports Bra for 2026, described as
the holy grail of sports bras for high-intensity workouts
womenshealthmag.com.
- Awards
Named best overall sports bra by Women's Health 2026 Fitness Awards and best for running by NBC Select.
Why this is supported
Women's Health 2026 Fitness Awards named this bra the best overall sports bra, describing it as
the holy grail of sports bras for high-intensity workouts
womenshealthmag.com. NBC Select similarly named it
Best for running
nbcnews.comafter testing dozens of styles against competitors like the Brooks Racerback 2.0.
- Key design features
Praised for bonded padding, adjustable straps, and all-workout comfort.
Why this is supported
Women's Health highlighted the
It’s built in—so you never have to deal with shifting, scrunching, or fishing pads out of the laundry
womenshealthmag.compadding and the
They distribute weight evenly across my shoulders without digging in
womenshealthmag.com, and found it
just as comfortable during slower sessions like yoga and pilates as it did during higher-intensity workout classes
womenshealthmag.com. Runners on Reddit also confirm the front-adjustable straps allow mid-run tightening and report
no chaffing!
u/quivera in r/RunNYC- Impact level
Medium-impact bra; may not support high-impact movements like jumping.
Why this is supported
The brand advises the bra is
designed for medium-impact activities such as running and intense sports
Is the bra suitable for high-intensity workouts like HIIT or jumping, or is it best for running only?and that it
may not provide enough support for high-impact movements like jumping
Is the bra suitable for high-intensity workouts like HIIT or jumping, or is it best for running only?. For high-impact workouts, they recommend a high-support bra.
- Chafe prevention
Seamless design, built-in padding, and adjustable straps prevent chafing on long runs.
Why this is supported
Reddit users report that the bra is
overall pretty seamless so no chafing or hot spots on long runs
u/Snickerfin in r/XXRunning. The built-in padding is a favorite detail:
One of our favorite details is the padding. "It's built in—so you never have to deal with shifting, scrunching, or fishing pads out of the laundry," Andriakos says.
womenshealthmag.com. Front-adjustable straps allow mid-run tightening:
It has adjustable straps in the front, so as I run and get sweaty, I can tighten it, keeping everything in place. So far no chaffing!
u/quivera in r/RunNYC. Wide straps evenly distribute weight:
They distribute weight evenly across my shoulders without digging in or creating pressure points during longer workouts.
womenshealthmag.comThese design elements collectively eliminate sources of chafing, making the bra suitable for extended runs.
- Recognition
Named best for running by NBC Select and winner of Women's Health 2026 Fitness Award.
Why this is supported
The bra has been recognized by NBC Select as
Best for running
nbcnews.comand won Women's Health's 2026 Fitness Award, which called it
the holy grail of sports bras for high-intensity workouts
womenshealthmag.com.
- Versatility
Equally comfortable without hot spots during yoga and Pilates as during running.
Why this is supported
In testing, the bra felt comfortable without hot spots across a range of activities:
In testing, it felt just as comfortable during slower sessions like yoga and pilates as it did during higher-intensity workout classes.
womenshealthmag.com- Fit features
Front-adjustable straps, bonded padding, and seamless design prevent shifting and chafing during workouts.
Why this is supported
The bra's front-adjustable wide straps
distribute weight evenly across my shoulders without digging in or creating pressure points during longer workouts
womenshealthmag.com. The bonded, built-in padding
never have to deal with shifting, scrunching, or fishing pads out of the laundry
womenshealthmag.com, and the seamless design eliminates chafing; a long-distance runner reported
So far no chaffing!
u/quivera in r/RunNYC.
- Cup range
Offers A-C and D/DD cup ranges within XS-XL sizing.
Why this is supported
The inclusive cup range is confirmed by a Reddit user:
It’s sized XXS to XL but also comes in an A-C cup and D/DD.
u/Snickerfin in r/XXRunning. On's official Q&A adds fit guidance:
On sports bras generally fit true to size. If you are between sizes, we recommend sizing up for a more comfortable fit, especially if you prefer a bit more room in the band and cups.
How does the bra fit compared to standard sizing? Should I size up if I'm between sizes?These sources together verify the size range and provide actionable advice.
The bra is available
sized XXS to XL but also comes in an A-C cup and D/DD
u/Snickerfin in r/XXRunning.
- Strap adjustability
Front-adjustable straps allow tightening during runs.
Why this is supported
A runner reports that
It has adjustable straps in the front, so as I run and get sweaty, I can tighten it, keeping everything in place.
u/quivera in r/RunNYCMeanwhile, a review from Women's Health notes that
They distribute weight evenly across my shoulders without digging in or creating pressure points during longer workouts.
womenshealthmag.com. These aspects allow the bra to be adjusted mid-activity for improved fit and comfort across different body types.
- Chafing prevention
Seamless construction prevents chafing on long runs, per buyers.
Why this is supported
Buyers report that the seamless design eliminates chafing:
So far no chaffing!
u/quivera in r/RunNYCand
it’s overall pretty seamless so no chafing or hot spots on long runs.
u/Snickerfin in r/XXRunning. These comments support the claim that seamless construction enhances comfort during extended wear.
- Dynamic fit
No cup gapping during planks or rows; adjustable straps maintain fit mid-activity.
Why this is supported
tighten it, keeping everything in place
u/quivera in r/RunNYCextra space at times, especially in hinging positions or during planks
thatfitfriend.com, a problem that the On bra's adjustable straps and wide support band are designed to address.
- High-impact limit
Medium support may not be enough for high-impact moves like jumping.
Why this is supported
The bra's medium support is appropriate for running and gym training, but a customer Q&A notes that for high-impact movements such as jumping, a high-support bra is recommended.
- Care routine
Cold gentle wash and hang dry; no fabric softener, bleach, or dryer.
Why this is supported
On recommends specific care to preserve the bra's elastic fibers:
We recommend machine washing cold on a gentle cycle and hanging to dry. Do not use fabric softener or bleach, and avoid machine drying as it can damage the elastic fibers.
What are the recommended care instructions? Can it be machine washed and dried?Following these steps helps maintain the spandex/elastane content and prolongs the bra's support.
- Padding design
Permanently bonded padding never shifts or needs realignment.
Why this is supported
The foam padding is permanently bonded into the cups, eliminating a common laundry nuisance:
It’s built in—so you never have to deal with shifting, scrunching, or fishing pads out of the laundry
womenshealthmag.comThis bonded design means the cups stay in place wash after wash, unlike removable pads that often shorten a bra's usable life.
- Seamless construction
Buyers report seamless construction reduces chafing and wear.
Why this is supported
The bra's mostly seamless build eliminates stitch lines that typically cause pilling or fraying over time. A runner on Reddit noted:
it’s overall pretty seamless so no chafing or hot spots on long runs
u/Snickerfin in r/XXRunningThis design contributes to longer durability and comfort.
Image Analysis
2 images- 01
Product
White sports bra with wide shoulder straps, smooth matte fabric, scoop neckline, a wide elastic underband and a small black woven logo tab at the lower right front. Two visible semi-sheer mesh inserts: a shallow curved panel at the upper chest and a curved under-bust panel.
- Overall silhouetteCropped sports-bra silhouette with a scooped front neckline, full-coverage front panel and a wide elastic underband that sits across the lower chest.
1 region
x 0.06 · y 0.18 · w 0.88 · h 0.45 (medium) - Shoulder strapsTwo straight, wide shoulder straps with a slightly textured seam where each strap meets the front chest panel; straps run vertically over the shoulders.
2 regions
x 0.20 · y 0.16 · w 0.16 · h 0.26 (high); x 0.58 · y 0.16 · w 0.14 · h 0.26 (high) - Chest mesh insertShallow curved semi-sheer mesh panel inset at the upper chest just below the scoop neckline.
1 region
x 0.29 · y 0.26 · w 0.42 · h 0.12 (high) - Under-bust mesh panelCurved semi-sheer mesh panel situated above the elastic underband at the center front, forming a subtle arc detail.
1 region
x 0.30 · y 0.46 · w 0.40 · h 0.10 (high) - Underband constructionWide elastic underband with a smooth finish and a stitched seam where it attaches to the main body of the bra.
1 region
x 0.12 · y 0.54 · w 0.76 · h 0.10 (high) - Logo tab“Small vertical black woven tab sewn into the lower right edge of the underband with two small white characters arranged vertically.”
1 region
x 0.66 · y 0.55 · w 0.07 · h 0.07 (high) - Fabric finishMain fabric appears smooth with a matte finish and minimal visible texture.
1 region
x 0.18 · y 0.24 · w 0.64 · h 0.46 (high)
Other
Studio shot of a model wearing the bra against a pale blue seamless background; model is cropped at hips, posed with left arm raised behind head, soft lighting and minimal shadows.
- Model poseFemale model shown from upper thighs to just above head with left arm raised and bent behind head, head tilted down and to the left.
1 region
x 0.00 · y 0.00 · w 1.00 · h 1.00 (low) - BackgroundEven pale blue seamless background with no visible props or patterns.
1 region
x 0.00 · y 0.00 · w 1.00 · h 1.00 (high) - Lighting and shadowSoft, diffused lighting producing gentle shadows under the chin and below the underband; highlights are subtle on the skin and fabric.
1 region
x 0.24 · y 0.10 · w 0.52 · h 0.70 (medium) - Bottom crop and visible shortsTop of the model's elastic waistband and a bit of lilac-colored shorts visible at the image bottom edge.
1 region
x 0.28 · y 0.66 · w 0.44 · h 0.20 (high)
Colors
bright white· main bodytranslucent white· mesh insertsblack· logo tab- Overall silhouetteCropped sports-bra silhouette with a scooped front neckline, full-coverage front panel and a wide elastic underband that sits across the lower chest.
- 02
Product
Rear view of a white sports bra worn by a model showing adjustable shoulder straps, a central racerback connector with a circular cutout, an elastic underband, and a small dark logo tag at the center back.
- Back geometryWhite sports-bra back with wide shoulder straps that converge to a central racerback connector piece; the connector forms a rounded arch opening (circular cutout) above the elastic underband.
1 region
x 0.26 · y 0.22 · w 0.48 · h 0.46 (high) - Adjustable strapsEach shoulder strap has an adjustable slider (same white color) located on the upper back portion of the strap.
2 regions
x 0.35 · y 0.18 · w 0.12 · h 0.18 (high); x 0.53 · y 0.18 · w 0.12 · h 0.18 (high) - Underband constructionWide elastic underband in the same white fabric running horizontally across the lower back with a visible stitched seam line above the band.
1 region
x 0.28 · y 0.55 · w 0.46 · h 0.12 (high) - Center back logo tagSmall dark rectangular logo tag affixed at the top of the racerback connector showing a small light mark or character on it (tag is dark with a lighter symbol).Partial
1 region
x 0.48 · y 0.35 · w 0.03 · h 0.04 (medium) - Fabric surfaceSmooth, slightly matte knit fabric with clean seams and minimal visible texture.
1 region
x 0.26 · y 0.22 · w 0.48 · h 0.46 (high)
Other
Model wearing the bra is shown from behind against a pale blue background; lower garment (lavender shorts with a black waistband) is visible and contains legible text. Lighting is soft and even with minimal shadowing.
- Model pose and framingTorso and upper hips of a model shown from the rear, left arm relaxed down and right arm raised with hand touching hair; image cropped above hips and above the head.
1 region
x 0.06 · y 0.02 · w 0.88 · h 0.96 (high) - Visible non-product garment text“SWISS ENGINEERING”
1 region
x 0.46 · y 0.78 · w 0.25 · h 0.06 (high) - Background and lightingUniform pale blue studio background with soft, diffuse lighting and minimal cast shadows.
Colors
white· bra main bodyblack· logo tagwhite· strap sliders- Back geometryWhite sports-bra back with wide shoulder straps that converge to a central racerback connector piece; the connector forms a rounded arch opening (circular cutout) above the elastic underband.
Documents & Data
Customer Reviews
1 total1 reviews · out of 5
Soutien on
Très bien fait, confortable
Reddit Insights
2 threads · r/RunNYC, r/XXRunningRedditors recommend the On Performance Flex Bra for running, praising its adjustable front straps and chafe-free design.
Both mentions are positive, recommending the bra for no chafing and adjustability.
Themes
Use Cases
- Running
Compared To
vs Brooks 3-Pocket Bra
User experienced chafing with Brooks 3-Pocket Bra and is hopeful about On Performance Flex Bra based on recommendation.
Source Threads
Positive experience with On Performance Flex Bra for running
Right now, my favorite bra is the Performance Flex Bra by On. It has adjustable straps in the front, so as I run and get sweaty, I can tighten it, keeping everything in place. So far no chaffing!
u/quiverar/RunNYCView thread →
Recommendation for On Performance Flex Bra highlighting seamless design
Check out the On Performance Flex bra. It’s sized XXS to XL but also comes in an A-C cup and D/DD. Straps are adjustable and it’s overall pretty seamless so no chafing or hot spots on long runs.
u/Snickerfinr/XXRunningView thread →