Success rate and factors that affect the ability to unscrew face masks from high school football helmets:  A retrospective cross-sectional study

Objective: Determine face mask (FM) removal success rate and identify and compare factors that influence removal success in used football helmets. Most previous research has used new equipment. Design and Setting: A retrospective cross-sectional study. Investigators (five ATCs) traveled to five equipment reconditioning facilities to attempt FM removal. Independent variables included: team, screw color (black, gold, silver, "other" - indicative of screw composition), reconditioning year, helmet brand and US geographic region (Northeast, South, Midwest, Rockies , Pacific). Dependent variables were removal success at each of four screw positions (2 side, 2 forehead). Subjects: 2,584 helmets from 44 high school teams. Selection was based on team size and location using plant client lists. Helmets were not visible during selection. Measurements: Helmet characteristics were recorded. Helmets were mounted in a custom bracket. FM removal was attempted using a cordless screwdriver. Investigators rotated every 15 helmets; charged batteries and screwdrivers were rotated every 45 helmets. Removal success and failure (including reason) were recorded for each screw. Failure rates between teams, reconditioning years and screw colors were compared using separate ANOVAs (Tamhane post-hoc). A discriminant analysis determined predictors of successful FM removal. (Alpha <.05). Results: Over half the helmets carried the Schutt brand (56.8%); 38.4% were Riddell. The sample included 552 helmets from Northeast teams (21.9%), 1,042 from South (40.3%), 438 from Midwest (16.9%), 209 from Rockies (8.1%) and 343 from Pacific (13.3%). All 4 screws were removed from 2,171 (84%) helmets; at least 1 screw could not be removed from 413 (16%). Mean screw failures per helmet ranged from 0.00 ± 0.0 to 1.0 ± 1.3 with significant differences between teams (p<.01) and reconditioning years (p<.01; the best rate (0.08 ± 0.29) in helmets new for the 2004 season and the worst rate (0.47 ± 0.93) in helmets not reconditioned since 2001). Five teams had higher than 98% removal success; five had lower than 55% success. Depending on screw location, 53-76% of failures were caused by spinning T-nuts. Significant differences in success rate (p<0.01) were found among the 4 screw colors, ranging from 97% success (silver screws) to 26% success ("other"). A discriminant analysis (p<.001) revealed screw color and reconditioning year to be among the strongest predictors of successful removal. Conclusions: Excellent results (10% of teams >98% success) are possible with the cordless screwdriver. Screw composition and maintenance history affe ct FM removal success. We recommend annual reconditioning and the use of metal hardware that resists degradation when exposed to football environments.

2006, Decoster LC, Swartz, EE, Norkus SA, Cappaert TA: Success rate and factors that affect the ability to unscrew face masks from high school football helmets: A retrospective cross-sectional study. J Athletic Training, Vol 41 (Suppl).  This project was fully supported by a grant from NOCSAE.