A sternum strap connects the two shoulder straps across the chest, at a height that’s usually adjustable up or down the straps. Its main job is stabilizing the pack’s position against the body, preventing the shoulder straps from sliding outward and off the shoulders during movement.
Beyond stability, a properly positioned sternum strap distributes some of the load more evenly across the chest and shoulders together, which can noticeably reduce the strain any single point feels compared with the shoulder straps alone bearing all the weight unassisted.
It’s a small, inexpensive feature but a genuinely useful one on any pack carried for more than a short walk — worth checking for and using even on packs where it’s easy to overlook, since it costs nothing to fasten and provides a real, if modest, comfort benefit.
Last reviewed 26 August 2026