Objectives Determine the validity and feasibility of current Instrumented mouthguards (iMGs) and associated systems.Methods Phase 1; Four iMG systems (Football Research Inc [FRI], HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase 2; Four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and false-negatives (20 ± 9 player matches per iMG). Phase 3; Four iMG systems were evaluated by eighteen rugby players, for perceptions of fit, comfort and function. Phase 4; Three iMG systems (FRI, HitIQ, Prevent) were evaluated for practical feasibility (system usability scale; SUS) by four practitioners.Results Phase 1; Total concordance correlation coefficient was 98.3%, 95.3%, 42.5% and 97.9% for FRI, HitIQ, ORB and Prevent. Phase 2; Different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for FRI, HitIQ, ORB and Prevent. Phase 3; player perceptions of fit, comfort and function were 77%, 6/10, 55% for FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB, and 85%, 8/10, 67% for Prevent. Phase 4; SUS was 51.3-50.6/100, 71.3-78.8/100, and 83.8-80.0/100 for FRI, HitIQ, and Prevent.Conclusion This study shows that differences between current iMG systems exist. Sporting organisations can use these findings to ensure accurate head acceleration event data are obtained and system adoption is optimized, to support player welfare initiatives directly related to long-term brain health
