A rotation monitoring system may be attached to a limb and can identify ranges of motion that are associated with injuries or poor performance. In some embodiments, the device is designed to monitor flexion and orientation of joints and limbs, developed specifically around identifying stress concentrating behavior on the ACL. Tests performed show that the designed device can read flexion and orientation of the knee, is durable enough to be used in real-world conditions, and does not impede on the subject's movements.
