McIntosh A S, Janda D
School of Safety Science, University of New South Wales, Sydney, NSW, Australia.
Br J Sports Med. 2003 Aug;37(4):325-30. doi: 10.1136/bjsm.37.4.325.
Protective helmets in sport are important for reducing the risk of head and facial injury. In cricket and other sports with projectiles, national test standards control the minimum helmet performance. However, there are few field data showing if helmets are effective in reducing head injury.
(a) To examine the performance of cricket helmets in laboratory tests; (b) to examine performance with regard to test standards, game hazards, and helmet construction; (c) to compare and contrast these findings with baseball and ice hockey helmets.
Impact tests were conducted on a selection of helmet models: five cricket, two baseball, and two ice hockey. Ball to helmet impacts at speeds of 19, 27, 36, and 45 m/s were produced using an air cannon and a Hybrid III dummy headform and neck unit. Free fall drop tests with a rigid headform on to a selection of anvils (flat rigid, flat deformable, and hemispherical rigid) were conducted. Resultant headform acceleration was measured and compared between tests.
At the lower speed impacts, all helmets produced a good reduction in headform acceleration, and thus injury risk. At the higher speed impacts, the effectiveness was less. For example, the mean maximum headform accelerations for all cricket helmets at each speed were: 67, 160, 316, and 438 g for 19, 27, 36, and 45 m/s ball speeds respectively. Drop tests on to a hemispherical anvil produced the highest accelerations. The variation in performance increased as the magnitude of the impact energy increased, in both types of testing.
The test method used for baseball helmets in which the projectile is fired at the helmet may be superior to helmet drop tests. Cricket helmet performance is satisfactory for low speed impacts, but not for impacts at higher, more realistic, speeds. Baseball and ice hockey helmets offer slightly better relative and absolute performance at the 27 m/s ball and puck impacts.
运动中的防护头盔对于降低头部和面部受伤风险至关重要。在板球和其他有投射物的运动中，国家测试标准控制着头盔的最低性能。然而，很少有现场数据表明头盔在减少头部受伤方面是否有效。
(a) 在实验室测试中检验板球头盔的性能；(b) 就测试标准、比赛危险和头盔构造检验性能；(c) 将这些发现与棒球和冰球头盔进行比较和对比。
对一系列头盔型号进行了冲击测试：五种板球头盔、两种棒球头盔和两种冰球头盔。使用空气炮和Hybrid III假人头型及颈部装置，以19、27、36和45米/秒的速度让球撞击头盔。对选定的砧座（平的刚性砧座、平的可变形砧座和半球形刚性砧座）进行了刚性头型自由落体跌落测试。测量了测试过程中头型的合成加速度并进行了比较。
在较低速度冲击下，所有头盔对头型加速度都有良好的降低效果，从而降低了受伤风险。在较高速度冲击下，有效性较差。例如，所有板球头盔在每种速度下的平均最大头型加速度分别为：球速19米/秒时为67克，27米/秒时为160克，36米/秒时为316克，45米/秒时为438克。在半球形砧座上的跌落测试产生的加速度最高。在两种测试中，随着冲击能量大小的增加，性能差异也增大。
用于棒球头盔的测试方法，即让投射物射向头盔，可能优于头盔跌落测试。板球头盔在低速冲击下性能令人满意，但在更高、更接近实际的速度冲击下则不然。在球速27米/秒时，棒球和冰球头盔在相对和绝对性能方面略胜一筹。
