Fig. 1 Fatal head injuries in football were drastically reduced following implementation of football helmet standards (left) [ 4 ]. Improvements in helmet design along with rule changes and teaching athletes proper tackling techniques have continued to reduce head injuries and fatalities in footba... More

Fig. 2 Organization of review. Injury metrics based on kinematics are presented first, which are subdivided into metrics based on translational motion, rotational motion, or a combination of translational and rotational motion. Tissue-based injury metrics are then subdivided into metrics derived f... More

Fig. 3 The Wayne state tolerance curve was developed through a collection of experimental efforts. Head injury tolerance for short impact durations (1–6 ms) was determined from cadaver drop tests onto a rigid surface [ 6 ]. The curve was extended to longer durations (6–10 ms) by linking injury out... More

Fig. 4 Mechanical model of the head used in development of the new mean strain criterion and translational energy criteria [ 40 , 43 ]. The model parameters were determined by fitting mechanical impedance of the model to experimentally determine mechanical impedance of primate or cadaver heads. ... More

Fig. 5 A recent study performed reconstructions of concussive impacts in NFL players. All impacts were head-to-head, and were reconstructed with two hybrid III ATDs propelled toward each other on sled tracks. Just prior to impact the dummies were released from the sled track to remove any external... More

Fig. 6 The damage brain injury metric rapidly predicts maximum brain strain from rotational head kinematics using a second-order mechanical system. The mechanical system parameters were determined by applying a wide range of sinusoidal rotational acceleration pulses to an FE head model. Real-world... More

Fig. 7 Concussion risk in terms of peak linear acceleration and peak rotational acceleration for impacts resulting in a diagnosed concussion in youth American football players. Risk was modeled in terms of a previously developed head injury metric (GAMBIT) adapted to concussion in youth football p... More

Fig. 8 Comparison of laboratory performance of helmets worn by NFL players with on-field concussion rates. A positive correlation between helmet performance using the HARM metric and on-field concussion rates shows that laboratory evaluation of helmets can demonstrate differences in helmet perform... More

Fig. 9 Examples of currently used instrumented mouthpieces and mouthguards. A custom retainer form factor developed at Wake Forest University is shown in ( a )–( d ). The embedded instrumentation ( a ), top view of the surface that interfaces with the palate ( b ), retainer fitted to three-dimensi... More