Reebok International Ltd. has teamed up with a small Cambridge technology company to make a device that fits under sports helmets to record hits to the head and help monitor athletes for possible concussions.

The device — a collection of flexible semiconductor sensors made by MC10 Inc. — is contained in a mesh skullcap made to be worn beneath protective headgear, be it for hockey, football, or another contact sport. It is expected to be commercially available next year.