Adjust Your Backpack Sternum Strap in Six Comfortable Steps

A sternum strap helps stabilize shoulder straps, but over-tightening can impair comfort. REI suggests roughly 1 inch below the collarbones; Osprey's pack-fitting guide uses about 2 inches. Treat these as design-specific examples and check freedom of breathing and arm movement.

3 min read2026-10-24

Official Osprey pack fitting video

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OriginalREI guide: pack fit orderREI

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What you need

Backpack with an adjustable sternum strap
Your normal everyday load
Mirror or someone to help check fit

How to

1. Pack the items you usually carry and put the backpack on so you can test the actual load.
2. Adjust shoulder straps first. For larger hiking packs, set the hipbelt and shoulder harness before the sternum strap.
3. Slide the sternum strap to a comfortable height beneath the collarbones. REI's example is about 1 inch below; Osprey's is about 2 inches. Follow your pack design.
4. Buckle it and pull only enough to stabilize the shoulder straps; do not compress your chest.
5. Swing both arms, walk and take several deep breaths. Loosen or reposition the strap if movement or breathing is restricted.
6. Check the full fit after a short walk. If the strap alone cannot make the pack comfortable, inspect the shoulder harness and pack size rather than tightening further.

One more tip

REI and Osprey describe different distances. Do not assume one number suits every bag or body. Follow your particular pack's guidance and loosen immediately if breathing or movement feels restricted.

Photos, videos, and links

OriginalOsprey official sternum strap positioningOsprey

# backpack # sternum strap # fit check