BACKGROUND Concern for head injuries is widespread and has been reported by the media to be the number one cause of decreased participation in football among the American youth population. Identifying player mechanisms associated with intentional, or purposeful, head impacts should provide critical data for rule modifications, educational programs, and equipment design. PURPOSE To investigate the frequency of intentional and unintentional head impacts and to examine the player mechanisms associated with intentional high-magnitude head impacts by comparing the impact mechanism distributions among session type, player position, and ball possession. STUDY DESIGN Cross-sectional study; Level of evidence, 3. METHODS Head impact sensors and video footage of 68 players were used to analyze and classify 1319 high-magnitude impacts recorded over 1 season of youth football. RESULTS In total, 80% of the high-magnitude head impacts were classified as being caused by intentional use of the head. Head-to-head impact was the primary impact mechanism (n = 868; 82.7%) within the 1050 intentional high-magnitude impacts, with classifiable mechanisms, followed by head-to-body (n = 139; 13.2%), head-to-ground (n = 34; 3.2%), and head-to-equipment (n = 9; 0.9%). Head-to-head impacts also accounted for a greater proportion of impacts during practices (n = 625; 88.9%) than games, for linemen (n = 585; 90.3%) than perimeters and backs, and for ball carriers (n = 72; 79.1%) than tacklers. CONCLUSION Overall, the majority of high-magnitude head impacts were intentional and resulted from head-to-head contact. The proportion of head-to-head contact was significantly higher for practices than games, linemen than backs and perimeter players, and ball carriers than tacklers.

中文翻译：

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美国青少年足球运动员是否故意将头用于高强度冲击？

背景技术对头部受伤的关注是广泛的，并且已经被媒体报道为在美国青年人群中减少参与足球运动的第一原因。识别与故意或有目的的头部撞击相关的参与者机制，应为规则修改，教育计划和设备设计提供关键数据。目的通过比较会话类型，球员位置和控球之间的冲击机制分布，调查故意和非故意头部撞击的频率，并检查与故意高强度头部撞击相关的球员机制。研究设计横断面研究；证据水平3。方法采用头部碰撞传感器和68名运动员的录像来分析和分类在1个赛季的青年足球中记录的1319次高震级撞击。结果总共有80％的高强度头部撞击被归类为故意使用头部造成的。头对头撞击是1050种故意高强度撞击中的主要撞击机制（n = 868； 82.7％），具有可分类的机制，其次是头对身体（n = 139； 13.2％），头对头撞击到地面（n = 34; 3.2％）和从头到设备（n = 9; 0.9％）。头对头冲击在练习中的影响比重（n = 625; 88.9％）也比游戏大；巡边员（n = 585; 90.3％）比外围和后方以及运球手（n = 72）大。 ; 79.1％）。结论总体而言，大多数高强度头部撞击是有意产生的，是由人与人之间的接触造成的。在练习中，头对头接触的比例显着高于比赛，巡边员比后排和外围球员以及持球者比铲球高得多。