Kendo Headgear Concussion Safety Evaluation

Concussions present a potential risk in various contact sports, including the martial art of kendo. While there are regulations implemented on the production quality of shinai, the bamboo-based swords used in kendo, there is a lack of active standards enforced by an independent governing body for kendo armor to prevent head injuries like concussions. Interestingly, two separate independent governing bodies exist to regulate and ensure the quality of commercially-sold shinai, but none for armor.This study aimed to answer two important questions: firstly, whether high-end kendo helmets offer superior protection against concussions compared to entry-level helmets, and secondly, whether adding extra padding inserts to the helmets enhances overall concussion protection.To conduct the study, we asked several kendo practitioners and one non-practitioner to deliver a series of head strikes using a shinai on a mannequin wearing different kendo helmets, both with and without additional protective padding. Our objective was to measure the force of each strike and assess the associated risk of concussion.The results indicated that both types of helmets sustained linear accelerations well below the threshold for the risk of concussion, which is set at 62.4g force. Notably, there were no statistical differences regarding impact forces received between the helmets (p-value equals 0.13).Interestingly, we found that commercial helmet padding inserts did not significantly reduce the risk of concussion. In fact, one of the commercially made helmet inserts performed worse than using a helmet alone (p-value is less than 0.01).In summary, our study suggests that investing in an entry-level kendo helmet with a 4 mm stitch pattern can offer comparable concussion protection to a high-end helmet with a 2 mm stitch pattern. As for commercially available padding inserts, their potential to provide additional concussion protection remains inconclusive and further studies are needed. Implementing a standardized evaluation process can aid consumers in making informed decisions when selecting protective gear to prevent concussions.