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Catalyst Sports Bra
High Support
Catalyst Sports Bra
$78.00
USD
10% off Bra & Underwear Sets*
Our most supportive sports bra
Eliminates bounce by 76%
Ventilation for increased airflow
Full coverage design
Size and Fit Guide
Use Our Calculator to Find Your Traditional Bra Size
Step 12 of 2
Your Results
Measure Your Under Bust
Measure Your Full Bust
Wearing an unpadded bra, wrap a measuring tape around the top of your ribcage. You’re looking for a snug fit - so we recommend tightening on the exhale and noting the smallest measurement to the decimal.
Wrap the measuring tape around the fullest part of your chest, making sure the measuring tape is paralell to the floor. Relax your shoulders and measure where it falls.
At Knix, your size is
Still have questions? Ask our virtual assistant about finding the perfect fit.
Still have questions? Book a virutal fitting with our amazing customer experience team!
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Product Description
High Impact Support
You are in control of your performance with our most supportive, full-coverage sports bra.
Feels Made For You
The traditional adjustable hook and eye back closure, featuring five rows, allows you to find the perfect fit easily.
Functional Style
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How to Choose?
Essential
- • Days you don’t need leak protection. Everyday freshness and moisture wicking.
-
0 tsp
Heavy
- • Extra peace of mind. For the first days of your cycle, light bladder leaks, or a full night's sleep without a leak.
-
about 8-14 tsp
-
about 1.5-3 regular pads
-
about 4-7 super tampons
-
about 1.5-3 menstrual cups
Light
- • Daily freshness. For sweat, discharge, period spotting, or backup protection.
-
about 1-3 tsp
-
about 1-3 pantyliners
-
about 1-3 regular tampons
-
about 0.5 menstrual cups
Moderate
- • For mid-cycle flow, surprise cough or sneeze leaks, or a really sweaty spin class.
-
about 4-8 tsp
-
about 1-1.5 regular pads
-
about 2-4 super tampons
-
about 0.5-3 menstrual cups
Ultra
- • Ultimate peace of mind. For the heaviest period days, light bladder leaks, unexpected postpartum flow, or overnight protection.
-
about 15-20 tsp
-
about 1.5-2.5 super pads
-
about 7-11 super tampons
-
about 2-3 menstrual cups
Sports Bras Comparison Chart
Catalyst Sports Bra
Maximum support
Full coverage
Reduces bounce by 76%
Momenta Racerback Sports Bra
Medium support
Mesh underband for ventilation
Pullover style
Longevity Sports Bra
Light support
Bra top with bonded-in cups
Pullover style
HIGH IMPACT SPORTS BRA
High Impact Support
Reduces Breast Movement
Tri Flo Ventilation
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Recently Viewed
Total 5 star reviews: 3.8k Total 4 star reviews: 794 Total 3 star reviews: 272 Total 2 star reviews: 175 Total 1 star reviews: 231
What our customers are saying
Generated by AI from 100 most recent customer reviews
Last updated 3 days ago
Customers say this sports bra provides excellent support and comfort for larger busts, with many wearing it all day. The wide straps and molded cups offer secure hold during high-impact activities like running and weightlifting. Many reviews mention the soft, breathable fabric and flattering fit without underwire. Common feedback includes concerns about sizing changes, with several noting the need to size up from previous versions. Some experience issues with strap placement and adjustment, particularly with newer models where straps may loosen or slip. While most praise the durability and long-term wear, a few mention quality concerns with adhesive or hardware over time.
90%would recommend this product
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Purchased Knix Size - Catalyst
5,265 reviews
- Rated 5 out of 5 stars6 hours agoCatalyst Sports Bra
This is the best sports bra i have ever had. In part that is because, with the help of the staff, i got one that fit perfectly.
Eileen G.Verified BuyerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars2 days agoMy favorite sports bra
This is my everyday bra when I teach. I love it. Pay attention to the sizing when you order. Get 5.
Samantha B.Verified BuyerReviewingCatalyst Sports Bra - Rated 2 out of 5 stars1 week agoNot comfortable
Unfortunately this bra is not comfortable at all, the sizing is weird because the cups are slightly too big and the band is too small despite me using the sizing guide. Unfortunately I couldn’t tell how uncomfortable the bra was until I had worn it longer than just trying on so the tags are off and I cannot return it.
Leah M.Verified ReviewerReviewingCatalyst Sports Bra - Rated 1 out of 5 stars1 week agostraps are too short
I have several old Calalyst Sports Bras that I really like, but they need replacement. I bought a new one in size M+ as I used to wear a 34 D bra before I bought your bras in size 4. My breasts come out underneath it unless I fasten it so tightly that I have to fasten it in the front and move it to the rear, which is a pain. I think the straps were shortened just enough so it no longer works for me. I didn't return it as I kept hoping it would get better. I'd like another, but not if my breasts slip out because the straps are too short.
Emily C.Verified BuyerReviewingCatalyst Sports Bra - Rated 4 out of 5 stars1 week agoWorkout
This is a great sports bra. Fits extremely well and keeps the girls in place.
Sylvia S.Verified BuyerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars3 weeks agoMay be a sport bra, but love this for everyday
I bought this bra on a whim along with another knix bra. As a very top heavy person, this is so worth it. So comfortable, band did not stretch (XXXXL++) out as the other one did and love that it is a large chested person can make this no wire bra packable. Will definitely buy this again and highly recommend. No spillage, comfortable and amazing hold.
Susan E.Verified ReviewerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars3 weeks agoCatalyst Sports Bra
Love this bra! It fits perfect and is so comfortable! Offers great support. Highly recommend! Bought one a few weeks ago and already ordered two more :)
Vicki S.Verified BuyerReviewingCatalyst Sports Bra - Rated 2 out of 5 stars3 weeks agoSizing issue and short straps
I've been buying Catalyst sports bras for many years and have always liked them. The last time I purchased, the sizing system had changed and I ordered the size according to the instructions on the website. It's not quite right (a bit small). However, the main issue is that the straps are way too short. I'm 5'9 and 160 lbs., so not overly tall and or overly heavy. With the straps at their very longest, the garment rides up all the time and is uncomfortable. I'm not sure why Knix got rid of the old ladder straps; the new system doesn't offer as much flexibility in terms of length. Unfortunately
I waited beyond the return period to try it, so I can no longer exchange it and am hesitant to order another one in a bigger size in case I have the same issue with the straps. I'm sad because this has been my go-to for many years and now I need another solution.
Christine G.Verified BuyerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars4 weeks agoGreat as usual!
Recently purchased a new catalyst. I've been wearing this sports bra since it first launched and it is a godsend. In the old sizing I used to wear a size 8 and now I'm wearing XXXL+ and the fit is good. Used the knix online measurement guide to find the recommended size.
Laura V.Verified BuyerReviewingCatalyst Sports Bra - Rated 3 out of 5 stars4 weeks agoSports Bra
This sports bra was quite tight even though I did make sure I bought within the recommended size. I know it is supposed to stretch and loosen over time but the process to get there is uncomfortable
Tina W.Verified BuyerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars4 weeks agoSurprisingly good
A very structured bra that really works. Very supportive. Have only used for sports; have not tried for daily wear.
Gerri A.Verified BuyerReviewingCatalyst Sports Bra - Rated 5 out of 5 stars4 weeks agoGreat Sports Bra
It has taken many searches to find the right sports bra. It is comfortable and flattering.
Katherine H.Verified BuyerReviewingCatalyst Sports Bra
