Protection effect of a neck protection device evaluated by surface electromyographic signal

Objective To evaluate the protection effect of a neck protection device (NPD) by analyzing neck muscle surface electromyographic signal (sEMG) for pilot.Methods Fifteen male subjects were tested under three conditions that were with no equipment, wearing helmet, and wearing helmet plus NPD respectively.At first, subjects flexed their necks from 10° to ultimate degree.Then subjects performed same maneuvers with helmet or with helmet and NPD when a 2.5 kg extra weight was appended on chin belt of helmet for simulating +Gz load.Neck sEMG was measured in all tests and root mean square (RMS) of amplitude was calculated.Results When flexing without equipment or only with helmet subjects' neck sEMG showed significant difference (F-160.454, 129.563, P＜0.01).For the subjects without any equipment, their neck sEMG appeared peak (5.99±1.99) mV as flexing to 30° when referenced to neutral position of head.But for the subjects with helmet the neck sEMG peak appeared at 40° flexing (10.14±3.80) mV.Within the 20° to 50° flexing range, helmet resulted in significantly higher neck sEMG comparing to no load condition (P＜0.05).Extra weight drove the incensement of neck tension.However, there was no significant difference in neck sEMG activity when flexed to any degree with helmet and NPD or to 50° with the extra weight.Conclusions Neck sEMG significantly increases when subject flexed with helmet or with an extra weight.The NPD could abate subject's tension on neck when wearing helmet. Key words: Head ;  Neck ;  Protective devices ;  Electromyography ;