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What makes the best sports bra?

What makes the best sports bra? Have you ever wondered? I am guessing the answer is YES as you are here reading this post. This used to be a matter of opinion until a recent study has found the features that are almost universally present in effective sports bras- the best sports bras.

What do I mean by ‘effective’? Well, the primary function of a sports bra is to reduce breast bounce. This can be very accurately measured in specialist bra testing labs, such as those of the University of Portsmouth.

The study looked into 10 features of sports bras and assessed 98 different style bras to see which features were consistently present in bras that provided the maximum bounce reduction. 

The features looked at were

  1. Bras style (compression, encapsulation or hybrid)
  2. Presence of an underwire
  3. Shoulder strap adjustability
  4. Shoulder strap configuration (straight, crossover or racerback)
  5. Principle fibre content (nylon or polyester)
  6. Underband adjustability
  7. Cup padding or moulding
  8. Underband closure type
  9. Underband closure location
  10. Neck drop (high, medium or low)

The ladies doing the testing were either 34B or 34D sized, supposedly to represent ‘smaller’ and ‘larger’ cup sizes.

Personally I think they missed a trick here- a lot of bras for bigger busts do not come in a 34D- Sculptresse by Panache starts at 34E, Elomi Energise at 34G, BXM Limitless at 34E. The study missed testing some bras which have been seriously engineered for support. Check out our bigger bust sports bra collection.

The bounce reduction for each sports bra was recorded (bare breasted running breast movement is compared to breast movement with each test bra). So each bra had a x% bounce reduction value. These values were then put into 3 equal sized groups.

  • The group of bras providing least bounce reduction (<54%) was classified as low support.

  • The middle group (54-63% reduction) = medium support.
  • The group of bras providing most bounce reduction (>63% reduction) were classed as high support bras, the best sports bras.
  • View our sports bra high impact collection here.
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The formula for the best sports bra is…

The study used some pretty mind bending statistical analysis to come up with some features that positively impacted bounce reduction. Drum rollllll, these were:

  • Encapsulation style. The number one feature contributing to bounce reduction was the bra style with encapsulation and hybrid both beating compression hands down.


Beyond that, features that contributed but to a lesser extent were:

  • Adjustable underband
  • Higher neckline, limiting vertical movement of breasts
  • Padded or moulded cups (often found in encapsulation styles)
  • Nylon as the predominant fibre type

That is not to say that is a sports bra does not tick all these features it is no good. For example the Enell Sport is pretty much universally acknowledged as the best sports bra in terms of support for larger breasted ladies; BUT it was not tested here as it does not come in a size that would work for a 34B. It is compression style, non adjustable back and non-padded 🤨

However as a general guide these are definitely features to be looking out for.  Lingerie companies are certainly incorporating these features in their sports bra designs. Check out the new design from Freya- the High Octane!

The adjustable underband will contribute to correct fit and the encapsulation style is generally only found in bras that are cup size specific. 

"Only 69% of bras marketed as 'high support' actually achieved bounce reduction in this study that classified them as such"
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Norris et al 2020
University of Portsmouth

Don’t believe the hype

Another interesting point- only 69% of bras marketed as ‘high support’ actually achieved bounce reduction in this study that classified them as such. (And remember this is only B & D cups!) It was because of this lack of transparent marketing that KnockerLocker developed the Power Rating.

This cleverly (if I do say so myself) provides a rating of 1-5, combining the impact of your chosen sport with your breast size. So as an example, if I am an E cup and want to run, I need a Power 4 or 5 bra to provide great support. If I want to do Pilates, a Power 2 or 3 sports bra will work fine.

If I am a petite B cup and want to run, a Power 2 will do the trick.

freya racerback sports bra

Shoulder strap orientation

Interestingly shoulder strap orientation was not found to be strongly associated with increased support. Although, I think most of us get a increased feeling of security from a racerback sports bra or crossback style. This maybe that fastening our J hook (seen here) just effectively shortens the straps.

Or regular?

Underwired or not?

Again there was not a strong indicator either way as to whether underwires increased the level of support given by a sports bra. So this one remains a matter of personal preference. Another study found that an overwhelming 74% of British women do not like an underwire in a sports bra. View our non-wired sports bra collection.

I think oftentimes wires cause issue digging in when the fit of the bra is incorrect and this is where the problem actually lies. The new wired sports bras from Panache, Freya and Elomi all have well encased and padded wires meaning all they give you is great shape. View the underwire sports bra collection.

The bottom line

This study gave some interesting insight into what features make the best sports bra. It does however have its limitations- it did not include larger breasted ladies in the study or indeed some of the sports bras designed specifically for bigger cups sizes.

Generally look out for: encapsulation or hybrid style, adjustable underband, high neckline (no plunge shapes please!), nylon fabric and a perhaps little moulding in the cups.

The rest is really up to your personal preference! What is the best sports bra for one lady will not necessarily be the best sports bra for her best friend. If you need a little more guidance as to what might provide great support for your breast size and chosen sport- please take a minute to read about our unique Power Rating or book in for an online fitting to chat through some options.

“How the characteristics of sports bras affect their performance”

Michelle Norris, Tim Blackmore, Brogan Horler, Joanna Wakefield-Scurr.