Abstract：
OBJECTIVE: To compare the impact attenuating capabilities between ice hockey helmets manufactured with and without XRD impact protection foam, worn with and without a XRD skullcap, at reducing sub-concussive head accelerations.
METHODS: Quasi-experimental laboratory.
METHODS: Ice hockey helmets were fit onto a Hybrid III 50th Head Form Head and dropped 25 times onto the left temporal side for each condition: XRD foam helmet, XRD foam helmet with XRD skullcap adjunct, non-XRD foam helmet, and non-XRD foam helmet with XRD skullcap adjunct. The helmets were dropped from a height that resulted in sub-concussive linear accelerations (25-80 g\'s). Using a tri-axial accelerometer, peak linear accelerations (g) were measured, and the average was used to compare impact attenuation properties across the four conditions.
RESULTS: The highest linear accelerations were observed in the XRD foam helmet without skullcap (32.97 ± 0.61 g) and were significantly greater (p < 0.001) than the XRD helmet with skullcap (21.38 ± 0.76 g). The helmet without XRD foam elicited the lowest peak linear accelerations (16.10 ± 0.73 g) which were significantly lower than the XRD foam helmet regardless of whether the skullcap was added (p < 0.001).
CONCLUSIONS: Although sub-concussive loads are potentially just as dangerous, much of the research regarding helmet and skullcap efficacy appears to be at high concussive impacts; <70 g\'s. The findings suggest that helmets with incorporated XRD foam, either within the design or added as an adjunct, are less effective at attenuating linear accelerations at sub-concussive levels than the low-density foam helmet.
METHODS: Quasi-experimental laboratory.
METHODS: Ice hockey helmets were fit onto a Hybrid III 50th Head Form Head and dropped 25 times onto the left temporal side for each condition: XRD foam helmet, XRD foam helmet with XRD skullcap adjunct, non-XRD foam helmet, and non-XRD foam helmet with XRD skullcap adjunct. The helmets were dropped from a height that resulted in sub-concussive linear accelerations (25-80 g\'s). Using a tri-axial accelerometer, peak linear accelerations (g) were measured, and the average was used to compare impact attenuation properties across the four conditions.
RESULTS: The highest linear accelerations were observed in the XRD foam helmet without skullcap (32.97 ± 0.61 g) and were significantly greater (p < 0.001) than the XRD helmet with skullcap (21.38 ± 0.76 g). The helmet without XRD foam elicited the lowest peak linear accelerations (16.10 ± 0.73 g) which were significantly lower than the XRD foam helmet regardless of whether the skullcap was added (p < 0.001).
CONCLUSIONS: Although sub-concussive loads are potentially just as dangerous, much of the research regarding helmet and skullcap efficacy appears to be at high concussive impacts; <70 g\'s. The findings suggest that helmets with incorporated XRD foam, either within the design or added as an adjunct, are less effective at attenuating linear accelerations at sub-concussive levels than the low-density foam helmet.
摘要：
目的：比较使用和不使用XRD冲击保护泡沫制造的冰球头盔之间的冲击衰减能力，戴着和不戴着XRD头盖帽，减少亚震荡的头部加速度。
方法：准实验实验室。
方法：将冰球头盔安装在HybridIII第50头形头上，并在每种情况下将其掉落到左颞侧25次：XRD泡沫头盔，XRD泡沫头盔与XRDskullcap辅助，非XRD泡沫头盔，和带有XRD头骨附属物的非XRD泡沫头盔。头盔从高处掉落，导致亚震荡的线性加速度（25-80g/s）。使用三轴加速度计，测量峰值线性加速度(g)，和平均值用于比较在四个条件下的冲击衰减性能。
结果:在没有头盖骨的XRD泡沫头盔(32.97±0.61g)中观察到最高的线性加速度,并且显著大于(p<0.001)具有头盖骨的XRD头盔(21.38±0.76g)。不含XRD泡沫的头盔引起最低的峰值线性加速度(16.10±0.73g),其显著低于XRD泡沫头盔,无论是否添加头盖骨(p<0.001)。
结论：尽管次震荡载荷可能同样危险，许多关于头盔和头盖骨功效的研究似乎是在高震荡影响下；<70克。研究结果表明，带有XRD泡沫的头盔，在设计中或作为附件添加，与低密度泡沫头盔相比，在衰减亚震荡水平的线性加速度方面效果较差。
方法：准实验实验室。
方法：将冰球头盔安装在HybridIII第50头形头上，并在每种情况下将其掉落到左颞侧25次：XRD泡沫头盔，XRD泡沫头盔与XRDskullcap辅助，非XRD泡沫头盔，和带有XRD头骨附属物的非XRD泡沫头盔。头盔从高处掉落，导致亚震荡的线性加速度（25-80g/s）。使用三轴加速度计，测量峰值线性加速度(g)，和平均值用于比较在四个条件下的冲击衰减性能。
结果:在没有头盖骨的XRD泡沫头盔(32.97±0.61g)中观察到最高的线性加速度,并且显著大于(p<0.001)具有头盖骨的XRD头盔(21.38±0.76g)。不含XRD泡沫的头盔引起最低的峰值线性加速度(16.10±0.73g),其显著低于XRD泡沫头盔,无论是否添加头盖骨(p<0.001)。
结论：尽管次震荡载荷可能同样危险，许多关于头盔和头盖骨功效的研究似乎是在高震荡影响下；<70克。研究结果表明，带有XRD泡沫的头盔，在设计中或作为附件添加，与低密度泡沫头盔相比，在衰减亚震荡水平的线性加速度方面效果较差。
