Updated: June 6th, 2021

Any coach worth their salt will advise driving the arms to counterbalance fatiguing legs, but of course it would help to have the right kit, sports bra included. Breasts have been identified as the 4th biggest barrier to exercise for women; ahead of facilities and cost would you believe it?

Therefore, as it turns out, your sports bra is one vital piece of kit; and not only for running.

Simply put, your breasts do not have any muscles, they are comprised of fatty tissue connected to your pectoral (chest wall) muscles via coppers ligaments and skin. These ligaments keep the shape and structure of your breasts, working together with the elastin in the skin; prevents unwanted sagging.

Naturally the breasts move independently from the body (held on by cooper’s ligaments) without sufficient support, prolonged exercise can result in breast pain, ligament strain and irreversible damage to cooper’s ligaments (which really will influence the shape, sagginess and pain you experience over time).

The average breast size in the UK is a 34D which according to curvykate bra specialists, is equivalent to carrying two guinea pigs (920grams total breast weight) compared to the average size 34B of 11 years ago; carrying two hamsters (460grams total breast weight).

Guinea pigs

So, investing in a quality, supportive sports bra is needed to prevent significant breast pain and limit the movement of Guinea pigs and hamsters on your chest when exercise, especially when running for three reasons:

  1. The repetitive plod-plod-plod pattern of each step invoking significant breast movement
  2. Your breathing
  3. Your stride length

Research suggests that running without a sports bra (or with a significantly unsupportive one) causes extra strain on the chest both from movement and breathing patterns; proven to cause quick and shallow breathing – directly inhibiting performance. Why?

Simple really, short breaths expend a lot more energy for little oxygenated reward. The less oxygen available to use means your muscles can not receive enough to really perform. “Taking deeper, slower breaths will deliver more oxygen to the muscles than short, shallow breaths, as you’re taking in more air and expending less energy” (Dr John Dickinson, Head of the respiratory Clinic at the University of Kent).

Brook’s research proves the lack of a supporting bra can shorten your stride length by 4cm, due to poorly contained lady guineapig movement (so if you run a marathon, you’ll end up running an extra mile!)

Woman in sports bra

Bra sizing, fitting, tips, tricks and everything in between.

Firstly, its important to understand some jargon. Sports bras often come in types of support coined as: low, medium and high impact, which you choose is all dependant on your size and workout activity.

  1. Low impact sports bras are for low impact activities (who’d have thought eh?) walking, yoga and strength training are good examples. The gunieas won’t be dealing with excessive movement, so they normally feature a cup-less design. Restricting movement by compressing the breasts against the chest wall.
  2. Medium impact sports bras are the next step in support, for those activities such as dancing, ski-ing and cycling. These sports bras feature a similar design to the low impact, however, offer more support and compression to keep the lady guineapigs in place.
  3. High impact sports bras offer the highest amount of support for running, aerobics and mountain biking type exercises. They typically contain defined cup structure (similar to regular bras) to encapsulate and support each breast. Some high impact bras utilise both encapsulation and compression to maximise the support you need.
  4. *(note, women with a larger breast size will need more support so opt for a medium impact sports bra for activities such as hiking and yoga to really support the lady guineapigs).


    Theres much debate over the perfect method for sports bra fittings, and honestly there is none. Measuring over the bust tissue and band really doesn’t work anymore with the measurements varying from country to country, brand to brand, range to range and even each women herself. So don’t sweat it.

    measuring womans body

    If you’ve never worn a sports bra before, start with your usual bra size, it should fit snugly without being so tight that you can’t breathe (cause y’know, that’s kind of important for running) when trying on your sports bra check these following points and you’ll be onto a winner:

  1. Band: check it is firm with 1-2inches of give available to actually breathe. Jump around in the changing room; the bra should move with you not independently. Also raise your arms up, if the band rides up – adjust the back closure or opt for a smaller size.
  2. Shoulder straps: again, ensure two fingers give between shoulder and strap is accessible. It shouldn’t dig in or glide off your shoulders. If you have a broader frame you may benefit from a cross-back strap style.
  3. Cup: wrinkles in the fabric is bad, indicating the cup is too big. Spilling out also isn’t ideal (sometimes the compression technology is intense) so ensure the cup feels natural and comfortable like your usual bras.
  4. Do the dance!: Mimick all the movements you will be doing, run on the spot, have a little one-woman-rave in the changing rooms before buying. Any discomfort or pain just swap in for another brand, type or colour (we all know colour matters).

Life of a sports bra.

The lifespan of your sports bra really depends how much you use it, there’s no time limit perse but once it stops being a little supportive running buddy, then its time to change; much like the life of your running trainers.

The tell-tale sign of needing to replace your sports bra is the laxity in the band (who wants laxity in a supportive relationship?) just remember to wash inside out on a low temperature and you’ll get along just fine.

Where to look next?

woman shopping

I’m glad you asked, there are some great options to try, I’ve linked some down below for you:

  • ‘Take a 90-day Test Run’ Brookes Run Bras are offering an incredible deal, try for 90 days. Not happy run right back to the store for a free return.
  • ‘M&S Extra high Impact non-wired sports bras size A-E’ this was a personal recommendation to me when training for my multiple marathon event. Marks and Spencer’s have done well on the bra front. Incredibly comfortable, front zipped for quick dressing and light on the price at £17.50!
  • And for those who need pockets?

  • Nike swoosh pocket bra £35 with 6 hidden pockets would you believe.
  • Berkeley bra £54 high support bra with pocket on the back of the racerback style sports bra, plenty of space for your dog-and-bone, (alright or just your phone)

There you have it, everything you need to know sports-bra wise to nail your next social run, training session or smash that PB, finally.

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