Five minutes into your HIIT class, and you are already pulling your bra back down. The straps are slipping. The band is riding up. Sound familiar?

You are not alone. Up to 90% of women wear the wrong sports bra size. We put together this guide so you never have to deal with that again.

Check our Pulse Sports Bra if you want to skip straight to the solution.

1. Signs Your Bra Does Not Fit

If any of these are true, your bra is working against you:

•       The band rides up your back during movement

•       Straps dig in, fall off, or leave shoulder marks

•       Breast tissue spills over the top or sides of the cups

•       Cups wrinkle or have empty space inside

•       You feel a lot of bounce even in low impact activity

•       You keep adjusting it mid-workout

 

2. The 4 Fit Zones to Check

Band

The band gives 80% of your support. It should sit level around your body, stay in place when you raise your arms, and allow two fingers to slide under with a little resistance. If it rides up, it is too loose.

Cups

All breast tissue should sit inside the cups with no spilling and no gaping. The fabric should be smooth and flat. The centre piece between the cups should press flat against your chest.

Straps

Straps are for position, not support. Two fingers should fit under each strap with slight resistance. They should stay in place during movement and not dig into your shoulders.

Overall Feel

You should breathe easily, move freely, and honestly forget you are wearing it. If you are aware of your bra during a workout for the wrong reasons, something needs adjusting.

Our Pulse Sports Bra is built to pass every one of these checks.

3. How to Measure Your Size at Home

All you need is a soft measuring tape and five minutes.

•       Measure under your bust for your band size. Round odd numbers up to the nearest even number.

•       Measure around the fullest part of your bust.

•       Subtract band from bust. The difference gives you your cup size.

 

Difference	Cup Size
Less than 1 inch	AA
1 inch	A
2 inches	B
3 inches	C
4 inches	D
5 inches	DD or E
6 inches	F

 

Example: Band 32 inches, bust 36 inches = 32D.

 

4. Match the Bra to Your Activity

 

Impact Level	Activities	What You Need
Low	Yoga, Pilates, walking	Light and breathable. Comfort first.
Medium	Cycling, hiking, dancing	Firm band, defined cups. Controlled movement.
High	Running, HIIT, CrossFit	Maximum support, wide straps, strong compression.

 

Research shows an unsupported bust can move up to 8 inches during running. A well-fitted high-impact bra reduces that by up to 74%.

For high impact training, pair the Pulse Sports Bra with our Pulse Sculpt Leggings for a full performance set.

5. Fit by Body Type

AA to B Cup

Compression or pull-on styles work great. Look for breathable fabric and a comfortable fit.

C to D Cup

Look for a balance of compression and individual cup support. Adjustable straps and a firm band make a big difference.

DD Cup and Above

Choose encapsulation style bras where each breast sits in its own cup. Wide padded straps, very firm band, and full coverage are essential for high-impact workouts.

Our Pulse Sports Bra is available in XS to 2XL and built for real support across all body types.

6. Three Quick Fit Tests

•       Jump Test: Jump for 15 seconds. Minimal bounce and a stable band mean a good fit.

•       Arms up Test: Raise both arms. The band should stay exactly where it is.

•       Two Finger Test: Slide two fingers under the band and each strap. Snug resistance is what you want.

7. Common Mistakes and Quick Fixes

 

Problem	Fix
Band rides up	Go down one band size
Band too tight or leaves marks	Go up one band size
Tissue spills over the cups	Go up one cup size
Cups wrinkle or gap	Go down one cup size
Straps dig in or fall off	Adjust straps. Check the band is fitted correctly
Too much bounce during workouts	Switch to a high-impact bra for that activity
Bra feels loose and worn out	Replace every 6 to 12 months with regular use

Compression vs encapsulation, what is the difference?

Compression presses the bust flat. Encapsulation supports each breast individually. For larger busts and high-impact workouts, encapsulation or a hybrid of both is the better choice.

Getting your sports bra fit right is one of the simplest things you can do to improve every workout. Now you know exactly what to look for.

Shop the Pulse Sports Bra and the full MN London Activewear range today.