118 - Comparing Impact and Concussion Risk in Leatherhead and Modern Football and Hockey Helmets

Poster Number: 118
Publication Number: 118.329

Jaxon J. Huang, University of Hawaii, John A. Burns School of Medicine, Kailua, HI, United States; Kellie Goya, University of Hawaii, John A. Burns School of Medicine, Honoluu, HI, United States; Ian Chun, University of Hawaii, John A. Burns School of Medicine, Honolulu, HI, United States; Brennan E. Yamamoto, Applied Research Laboratory, University of Hawaii, Honolulu, HI, United States; Loren G. Yamamoto, University of Hawaii, John A. Burns School of Medicine, Honolulu, HI, United States

Background: Improvements in the modern helmet have demonstrated beneficial effects in reducing concussion risk in football players. However, previous studies and existing data yield conflicting results regarding the protective quality of leatherhead helmets.

Objective: This study compared the head acceleration produced in a leatherhead football helmet (LH) versus a modern football helmet (MF) versus a modified modern football helmet (ModF) (with softer foam placed on the inside after removing existing padding) versus a hockey helmet (H) in helmet-to-helmet strikes.

Design/Methods: Each helmet was placed on a Century Bob Manikin and struck with various combinations. Accelerometers were placed on the manikin’s head at the apex, frontal, and temporal regions, and collected data in three dimensional X, Y, and Z axes. The striking helmet contained a 9.7lb weight, was hung from a rope at a fixed length (46in) and raised 45° from horizontal, then released to strike the helmet on the manikin. The peak linear acceleration (PLA) was determined in each helmet-to-helmet strike and repeated for a total of 20 trials.

Results: Mean PLA values in three dimensional axes of 100 total helmet-to-helmet impacts were obtained and measured in gravitational G units (9.8 m/sec^2). The results are displayed in Table 1 and Figure 1.

Each type of helmet was placed on the manikin head and struck with a MF. When LF was struck, significantly greater PLA values in all three axes were produced in comparison to H and MF. Compared to ModF, the LF produced significantly greater PLA values in the apex and frontal regions. ModF had a significantly greater PLA in the frontal and temporal regions compared to H. MF had a significantly greater PLA in the frontal and temporal regions compared to H. MF also had a greater PLA in the temporal region compared to ModF. In the apex and frontal axes, H had the lowest PLA followed by MF and ModF, which were not significantly different from each other. In the temporal axis, H had the lowest significant PLA, followed by MF, then ModF.

The PLA generated between two of the same type of helmet demonstrated a significantly greater PLA in a MF to MF strike in all three dimensional axes than in a H to H strike.Conclusion(s): The results demonstrated that LF was the least protective in terms of reducing PLA. The ModF did not provide a significant difference compared to MF. A significantly greater PLA was produced between two MF when compared to two H. These results provide additional insight into the inconclusive evidence regarding the safety of LF and into the design of future football and hockey helmets.
Table 1.Summary of results. Values are expressed as mean peak linear acceleration (PLA), standard deviation (SD), standard error (SE), and 95% confidence interval of the mean (95% CIM) at the apex, frontal, and temporal regions. Helmet type is labeled as striking helmet to manikin helmet.
Figure 1.Linear acceleration in gravity G units (1 G = 9.8 m/sec^2) for each helmet-to-helmet (swinging helmet to manikin helmet) impact at the apex, frontal, and temporal regions.