Sizing & fit guide

AY Athletics pieces are designed for movement first. Our fits are intentional, not fashion-driven, not oversized, not restrictive. Use this guide to choose the size that lets you move freely and confidently.

Our Fit Philosophy

  • Performance-focused: Close to the body without compression

  • No excess fabric: Nothing flaps, nothing distracts

  • Designed for running: Tested in motion, not just standing still

If you’re between sizes:

  • Size down for a race-day feel

  • Size up for relaxed training or layering

Men’s Long-Sleeve Running Top 

Measurements (cm)

Size Length (in/cm) Bust (in/cm) Sleeve (in/cm) Zipper length (in/cm)
XS 26.0 / 66 39.0 / 99 27.4 / 69.5 7.1 / 18
S 27.0 / 68.5 42.0 / 106.6 27.6 / 70 7.1 / 18
M 28.0 / 71.1 45.0 / 114.2 27.8 / 70.5 7.1 / 18
L 29.0 / 73.6 48.0 / 122 28.0 / 71 7.1 / 18
XL 30.0 / 76.2 51.0 / 129.6 28.1 / 71.5 7.1 / 18
2XL 31.0 / 78.7 54.0 / 137.2 28.3 / 72 7.1 / 18
3XL 31.5 / 80 58.0 / 147.4 28.5 / 72.5 7.1 / 18
4XL 32.0 / 81.3 62.0 / 157.4 28.7 / 73 7.1 / 18
5XL 32.5 / 82.6 65.9 / 167.4 29.0 / 73.5 7.1 / 18


How it should feel:

  • Light contact on chest and arms

  • Full shoulder mobility

  • No restriction when arms swing

If you prefer:

  • Race fit → true to size

  • Layering fit → size up

Men’s Running Short

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Measurements (cm/inch)

Size Length Waist Hip Thigh circumference Inseam
XS 36 / 14.2 71.5 / 28.1 100 / 39.4 65 / 25.6 13 / 5.1
S 37.5 / 14.8 74 / 29.1 104 / 40.9 67 / 26.4 13 / 5.1
M 39 / 15.4 76.5 / 30.1 108 / 42.5 69 / 27.2 13 / 5.1
L 40.3 / 15.9 79 / 31.1 112 / 44.1 71 / 28 13 / 5.1
XL 42 / 16.5 81.5 / 32.1 116 / 45.7 73 / 28.7 13 / 5.1
2XL 43.5 / 17.1 84 / 33.1 120 / 47.2 75 / 29.5 13 / 5.1
3XL 45 / 17.7 86.5 / 34.1 124 / 48.8 77 / 30.3 13 / 5.1
4XL 46.5 / 18.3 89 / 35.0 128 / 50.4 79 / 31.3 13 / 5.1

 

  • Secure waistband without digging

  • No pull when lifting knees

  • Fabric stays close without clinging

How to Measure Yourself

  • Chest: Measure around the fullest part of your chest

  • Waist: Measure at your natural waist (relaxed)

  • Hip: Measure around the widest part of your hips

  • Sleeve: From shoulder seam to wrist

  • Inseam: From crotch to hem

Measure once. Don’t overthink it.

Still Unsure?

If you’re hesitating between two sizes, choose the one that matches how you run, not how you stand.

  • Fast & minimal → smaller size

  • Long runs & comfort → larger size

You can also reach us anytime via the Contact page.