New guidance on concussions shows there isn’t enough solid evidence to answer some of parents’ most burning questions about contact sports. That includes what age is safest to start playing them.

新的脑震荡指导显示，没有足够的确凿证据来回答父母关于接触性运动的一些最紧迫的问题。这包括什么年龄开始玩游戏最安全。

Pediatric experts in sports medicine, neurology and related fields evaluated and rated three decades of sports concussion-related research. They say recent evidence filled in some blanks. Such as:

运动医学、神经病学及相关领域的儿科专，家对30年来运动性脑震荡相关研究进行了评估和评级。他们说最近的证据填补了一些空白。例如：

• Teen girls face higher risks than boys for concussions when playing the same sport by the same rules
• 按同样的规则做同样的运动，少女比男孩面临更大的脑震荡风险
• Hockey body checking bans reduce concussions in players under 13
• 曲棍球身体检查禁令减少13岁以下运动员的脑震荡
• Limiting contact in youth tackle football results in fewer head impacts.
• 在青少年铲球比赛中限制接触会减少头部撞击。

“Parents worry, ‘Is one concussion to my child going to result in him having dementia at age 50?’” said lead author, Dr. Frederick Rivara. “And the data are pretty clear that the answer is no.”

“家长们担心，'我的孩子一次脑震荡会导致他在50岁时痴呆吗?”主要作者弗雷德里克·里瓦拉博士说。“数据很清楚，答案是否定的。”

But it remains uncertain how many concussions are too many, when to call it quits, and what are the long-term consequences of multiple concussions in youth sports. Still, parents shouldn’t let the unknowns and undue fears keep kids from playing sports, he said.

但目前仍不清楚到底有多少脑震荡太多，何时叫停，以及青少年体育运动中多发脑震荡的长期后果如何。他说，尽管如此，家长们不应该让这些未知和不必要的恐惧阻碍孩子们参加体育活动。

“The last thing we want to tell kids is not to be active,” said Rivara, a pediatrician and injury prevention researcher at the University of Washington’s medical school.

华盛顿大学医学院儿科医生和伤害预防研究员里瓦拉说：“我们最不想告诉孩子们不要太积极。”

The panel’s consensus statement was published online Monday in the journal JAMA Pediatrics.

专家组的共识声明周一在《美国医学会儿科杂志》在线发表。

Among the conclusions:

结论如下：

• Kids should be taught collision techniques before beginning play in contact sports.
• 在开始接触式运动之前，孩子们应该学习碰撞技术。
• There is not conclusive evidence that younger children face higher risks for getting sports-related concussions.
• 没有确凿的证据表明年幼的孩子更容易患上与运动有关的脑震荡。
• Evidence is inconclusive on whether multiple childhood concussions are linked with long-term neurological changes
• 关于儿童多发性脑震荡是否与长期的神经系统改变有关，目前尚无定论。
• Technology that measures head impact exposure, and advanced brain imaging techniques, are both experimental and not ready for use.
• 测量头部撞击暴露的技术，以及先进的脑成像技术，都是实验性的，还没有准备好投入使用。
• Helmets should be worn in high-impact sports though there’s little or no evidence that headgear prevents concussion in rugby and soccer.
• 在高强度运动中应该戴头盔，尽管很少或没有证据表明头盔可以防止橄榄球和足球中的脑震荡。

Also called mild traumatic brain injury, concussions are caused by a bump or jolt to the head. The impact causes the brain to bounce or twist, potentially damaging brain cells. Repeated concussions have been linked with a debilitating brain disease found in autopsies on some retired football players.

脑震荡也被称为轻度创伤性脑损伤，脑震荡是由头部的撞击或颠簸引起的。撞击会导致大脑反弹或扭曲，可能会损伤脑细胞。在一些退役足球运动员的尸检中发现，反复的脑震荡与使人衰弱的大脑疾病有关。