Why Breast Support In Your Sports Bra Should Be Your Next Smart Move (on and off the track)

Head of Female Run Coaching and Head Strength and Conditioning Coach Molly Butterworth on all things Training Sports Bra related and how Pebe can help you on your fitness journey

We've all heard the saying: “Failing to prepare is preparing to fail.” At PGC1, that applies to everything—your training, your recovery… and yes, your sports bra choice. Because whether you're chasing a marathon time or weekend hill repeats, neglecting proper breast support isn't just uncomfortable—it can undermine your stride, your technique, and your confidence.

1. Understand the Mechanics: Why It Matters

Sports bras are not fashion accessories — they’re performance gear. Breasts lack inherent structural support; they’re held in place by skin alone. This isn't a big deal at rest, but once you start moving, things change quickly. During running, for instance:

• Breasts can shift up to 50% vertically.

• Side-to-side and front-to-back movement make up around 25% each.

• Total displacement can reach 14 cm, and even A-cup breasts can bounce up to 4 cm.

That much motion can disrupt your biomechanics, affect your posture, and even elevate injury risk. The takeaway? Support matters—regardless of breast size.

2. Find a Sports Bra That Works for You

Here’s where fit meets function. At PGC1, we’re all about training smarter—and that starts with choosing the right sports bra. Compression vs encapsulation: Know your activity. High-impact efforts (like intervals or tempo runs) typically benefit from encapsulation or hybrid designs—more structure. Light movement? Compression may suffice.

• The underband does the heavy lifting. It should feel snug against your ribcage without restriction. If the support is riding on the straps, you’ve already missed the mark.

• Fit isn’t one-size-fits-all (pun intended). Focus on how the sports bra feels when you’re in motion, not just static measurements. Think: does it stay put mid-run? Does it compress without cramping?

Time spent finding the right fit is an investment—and one you’ll thank yourself for every stride.

3. Size Isn’t a Shield—but Size-Tailored Support Is

Whether you're an A-cup or cup-plus athlete, everybody has unique support needs.

• Smaller chests are still susceptible to noticeable displacement—you’re not off the hook just because your cup size is small.

• Larger chests often face added challenges—strap cutting, back strain, or ill-fitting bras that compromise comfort and mobility.

So choose with intention. Try styles, test them during movement, and don’t settle for discomfort.

4. Make Smart Choices the Same Way You Build Training Blocks

At PGC1, our philosophy revolves around consistency, structure, and longevity. Applying that to breast support, here's a three-step process:

1. Get measured properly, ideally during movement or using a trusted fitting guide.

2. Match the style to your training—light jogs? Day-to-day tanks could work. Track sessions or tempo runs? Lean in on high-impact designs.

3. Test, adjust, reassess. Fit can change over time—tech fabric fatigue, wear and tear—so revisit regularly.

   
   

5. Protective, Practical, Performance-Oriented Support

This isn’t vanity—it’s about safeguarding your body for the long run.

• The right bra preserves skin integrity and keeps your posture and mechanics intact.

• A good fit reduces distractions and lets you commit fully to the session ahead.

• Fit and comfort enhance confidence. (Confidence is one of the best performance boosters we know).

  
  

Final Thoughts: Train Hard, Train Smart—Down to the Undergarments

If you’re serious about running, triathlons, Hyrox, or even your local parkrun, every detail matters—including what’s under your vest. Breast support might feel niche, but it’s one of those small but mighty factors that quietly elevates comfort, performance, and long-term training health. Getting a proper fit with Pebe was a game changer after spending years being unable to find a sports bra that had everything I needed to be comfortable and supported. They also provide a range of resources on their website to help you avoid common sports bra mistakes and find the best fit for you!

Schedule a quick time to get properly fitted. Try a couple of styles and put them through the paces. Your biomechanics—and weekend long runs—will thank you.

This blog was written by our Head of Female Running Coaching and Head Strength and Conditioning Coach Molly Butterworth. Having competed at a national level within Athletics for over a decade Molly progressed into initially coaching Strength and Conditioning before becoming the Head of Female Run Coaching at PGC1 in 2024. Molly combines her extensive knowledge from her own running alongside having worked with athletes at all levels within her career. Molly is incredibly passionate about engaging female audiences into fitness and supporting their journeys through expert guidance and a female athlete first led approach to health and fitness.