How do the neck muscles influence head acceleration during sport-associated impact events in high school athletes?

项目总结/摘要 运动相关脑震荡是一种常见和严重的伤害，约780万学生运动员参加比赛， 一个成功的策略，以减少脑震荡的风险，其 在这一人群中的相关不利的短期和长期后果将推动 增进健康，减少疾病和残疾，促进儿童充分实现其 健康和富有成效的生活的潜力。颈部强化运动可能代表这样的干预。 颈部较小、较弱的运动员被认为患脑震荡的风险更高，因为他们的颈部 在与运动有关的碰撞过程中， 产生的净头部加速度。然而，我们对控制颈部的机制的理解， 对头部加速度的影响仍然是不完整的，这种关系可能会被修改， 演习仍不清楚。这些问题必须回答之前，颈部加强锻炼计划 可以优化以降低运动员脑震荡的风险。拟议的机制前瞻性临床试验将 具体目标如下：目的1）确定手动阻力颈部强化的效果 在多种模拟运动条件下对颈部力量、颈部肌肉体积和头部净加速度的锻炼- 相关的冲击条件;目的2）确定颈部力量和颈部肌肉的相对影响 在模拟运动相关的头部和身体撞击过程中， 没有意志性的预期的颈部肌肉预收缩来支撑冲击。AIM 1的方法 将是一系列重新评估低或高强度的手动阻力颈部强化练习的效果， 在每种冲击条件下，关键颈部肌肉属性和头部净加速度的程序。 评估将在108名高中运动员的基线和完成4，8和12 周的运动干预，与对照组相比，参与“肩膀向下” 没有专门针对颈部的锻炼计划。AIM 2的方法是比较R2值 使用基线数据收集的统计模型，有和没有预期的颈部肌肉预收缩 根据颈部力量、颈部肌肉体积或两者来预测头部净加速度。本研究 有望建立手抗颈锻炼的量效关系， 颈部力量，颈部肌肉体积和头部净加速度，以及定义机制， 颈部在头部和身体受到冲击时控制头部加速度， 肌肉预收缩以应对冲击这项工作将提供重要的机械洞察力， 颈部肌肉抵抗头部加速度，这将最终导致改善颈部强化锻炼 运动员的节目。这样做，这项工作将有助于减少脑震荡的长期目标- 通过制定颈部强化运动处方来降低相关发病率。

PROJECT SUMMARY/ABSTRACT Sport-related concussion is a common and serious injury in the ~7.8 million student-athletes who compete at the high school level each year in the U.S. A successful strategy for reducing the risk of concussion and its associated adverse short- and long-term consequences in this population would advance the mission of enhancing health, reducing illness and disability, and promoting children’s chances to achieve their full potential for healthy and productive lives. Neck strengthening exercise may represent such an intervention. Athletes with smaller, weaker necks are thought to be at increased risk for concussion because their necks are less able to counter the forces acting on their heads during sport-associated collisions, leading to greater resultant net head accelerations. However, our understanding of the mechanism governing the neck’s influence over head acceleration remains incomplete, and the potential for this relationship to be modified by exercise remains unclear. These questions must be answered before neck strengthening exercise programs can be optimized to reduce athletes’ risk of concussion. The proposed mechanistic prospective clinical trial will pursue the following specific aims: AIM 1) to determine the effect of manual resistance neck strengthening exercise on neck strength, cervical muscle volume, and net head acceleration under multiple simulated sport- associated impact conditions; AIM 2) to determine the relative influences of neck strength and cervical muscle volume on net head acceleration during simulated sport-associated impacts to the head and body, with and without volitional anticipatory cervical muscle pre-contraction to brace for the impact. The approach to AIM 1 will be to serially reassess the effects of a low or high intensity manual resistance neck strengthening exercise program on key cervical muscle attributes and net head acceleration under each impact condition. Assessments will be performed in 108 high school athletes at baseline and upon completion of 4, 8, and 12 weeks of the exercise intervention, with comparison to a control group participating in a “shoulders-down” exercise program not specifically targeting the neck. The approach to AIM 2 will be to compare the R2 values of statistical models using baseline data collected with and without anticipatory cervical muscle pre-contraction to predict net head acceleration based on either neck strength, cervical muscle volume, or both. This research is expected to establish dose-response relationships for manual resistance neck strengthening exercise on neck strength, cervical muscle volume, and net head acceleration, as well as define the mechanism by which the neck controls head acceleration during impacts to the head and body with and without anticipatory cervical muscle pre-contraction to brace for the impact. This work will provide important mechanistic insight about how the cervical muscles resist head acceleration that will ultimately lead to improved neck strengthening exercise programs for athletes. In doing so, this work will contribute to the long term objective of reducing concussion- related morbidity through the prescription of neck strengthening exercise.