%0 Journal Article
%T Evaluation of an In
%A Andrew S. McIntosh
%A Inga Katharina Koerte
%A Roald Bahr
%A Stian Bahr Sandmo
%A Thor Einar Andersen
%J The American Journal of Sports Medicine
%@ 1552-3365
%D 2019
%R 10.1177/0363546519826953
%X Wearable sensor systems have the potential to quantify head kinematic responses of head impacts in soccer. However, on-field use of sensors (eg, accelerometers) remains challenging, owing to poor coupling to the head and difficulties discriminating low-severity direct head impacts from inertial loading of the head from human movements, such as jumping and landing. To test the validity of an in-ear sensor for quantifying head impacts in youth soccer. Descriptive laboratory study. First, the sensor was mounted to a Hybrid III headform and impacted with a linear impactor or a soccer ball. Peak linear acceleration (PLA), peak rotational acceleration (PRA), and peak rotational velocity (PRV) were obtained from both systems; random and systematic errors were calculated with Hybrid III as reference. Then, 6 youth soccer players wore sensors and performed a structured training protocol, including heading and nonheading exercises; they also completed 2 regular soccer sessions. For each accelerative event recorded, PLA, PRA, and PRV outputs were compared with video recordings. Receiver operating characteristic curves were used to determine the sensor¡¯s discriminatory capacity in both on-field settings, establishing cutoff values for predicting outcomes. For the laboratory tests, the random error was 11% for PLA, 20% for PRA, and 5% for PRV; the systematic error was 11%, 19%, and 5%, respectively. For the structured training protocol, heading events resulted in higher absolute values (PLA = 15.6g¡À 11.8g) than nonheading events (PLA = 4.6g¡À 1.2g); the area under the curve was 0.98 for PLA. In regular training sessions, the area under the curve was >0.99 for PLA. A 9g cutoff value yielded a positive predictive value of 100% in the structured training protocol versus 65% in the regular soccer sessions. The in-ear sensor displayed considerable random error and substantially overestimated head impact exposure. Despite the sensor¡¯s excellent on-field accuracy for discriminating headings from other accelerative events in youth soccer, absolute values must be interpreted with caution, and there is a need for secondary means of verification (eg, video analysis) in real-life settings. Wearable sensor systems can potentially provide valuable insights into head impact exposures in contact sports, but their limitations require careful consideration
%K TBI
%K repetitive
%K soccer
%K subconcussive
%K wearable
%K accelerometer
%U https://journals.sagepub.com/doi/full/10.1177/0363546519826953