Women's Fly Sports Bra Fit and Support Guide
By BOA | Running Shorts & Apparel | Made in the USA | Published: 2026-10-23
Category: Buying Guides
Learn how the Women's Fly Sports Bra fits and supports during runs. Get sizing tips, decision rules, and fit guidance for medium-impact activities.
Quick answer
The Women's Fly Sports Bra is a medium-support racerback design best for runs, gym sessions, and everyday wear. Use our fit rules below to find the right band and cup size.
Why support level matters for running
Running creates repetitive impact that can strain breast tissue. A medium-support bra like the Fly Sports Bra works well for moderate-paced runs, cross-training, and yoga. For high-impact sprinting or long-distance races, you may want a higher-support option.
Racerback design trade-offs
The racerback cut gives full range of motion for your shoulders and arms, which helps during dynamic movements. The keyhole cut-out adds ventilation but may show under certain tank tops. If you prefer a seamless look under low-cut tops, consider a different neckline.
Decision rules for the right fit
- Check the band first: Measure your underbust snugly. The band should be level and snug on the loosest hook. If it rides up, size down.
- Cup volume matters: The Fly Sports Bra is designed for medium support. If you have a larger cup size (D+), test the fit with a jumping jack. If you feel excessive bounce, consider a high-support bra. For D+ cups, a high-support bra may be more comfortable.
- Shoulder strap tension: Adjustable straps should not dig in or slip off. The racerback design naturally stays in place, but check that the keyhole cut-out does not pinch your shoulder blades.
Product facts
- Women's Fly Sports Bra: Racerback design with a keyhole cut-out for breathability and style. This keeps you cool during sweaty runs and allows full arm movement without chafing.
Women's Fly Sports Bra
Who this bra works for
Best for
- Medium-impact runs, gym workouts, and yoga
- Runners who prefer a racerback cut for shoulder mobility
- Everyday wear under casual tops
Not for
- High-impact sprinting or long-distance races where maximum support is needed
- Larger cup sizes (D+) who may need a high-support encapsulation bra
