This three-year study will determine the effectiveness of a helmetless tackling training intervention to decrease head impact exposure in Hawaiian high school football players.

High school football participants are reported to sustain an average of 600, and as many as 2000, head impacts in a single season. Impacts to the top and front of the helmet generate the greatest forces, and thus pose the highest risk for acute brain and spinal cord injury. Equally disconcerting is the potential relationship between the accumulation of concussive and sub-concussive impacts (head impact exposure, HIE) and the risk for developing long-term conditions such as cognitive impairment, early-onset Alzheimer's, and chronic traumatic encephalopathy (CTE). Tackling and blocking behaviors using the head as the point of first contact can be attributed, in part, to the fact that players wear a helmet, which influences behavior by increasing the perception of safety.

The central hypothesis is such that a football player who regularly practices tackling and blocking drills without a helmet in a controlled environment will naturally leave the head out of contact and is likely to continue to do so while wearing the helmet during games and full-contact practices. This learned motor behavior will reduce the number of head impacts a football player experiences throughout their playing career and thus reduces the risk of acute and chronic head and neck injury.

The investigation will be a pre-test, post-test quasi experimental design using an evidence-based helmetless tackling and blocking program (HuTT®) with football players (~200) recruited from high school football teams in Oahu, Hawaii.

Year 1 will serve as a baseline and entail collecting only head impact data during regular football participation for two teams. After adding a third team for years 2 and 3, all subjects will then undergo the HuTT® Program intervention emphasizing proper tackling and blocking techniques under closely supervised drills where players participate without their helmets and shoulder pads in place.

From the outset, subjects will use a new Speedflex helmet outfitted with the InSite™ head impact sensor (Riddell, Co). The helmet and sensor will be worn in all practices and games and used to record head impact exposure (frequency, location, and magnitude). ImPACT tests will be conducted at pre- and post-season intervals to measure verbal and visual memory composite, visual motor speed composite, reaction time composite and symptoms scores. In addition, player self-efficacy for head-safe behavior will be scored each year using a self-reported survey.

A between-subjects ANOVAs will be used to compare outcome measures among teams. Significant interactions and main effects will be identified by appropriate t-tests with Bonferonni corrections at an alpha-level of 0.05.

Inclusion Criteria:

• be a member on one (junior varsity or varsity) of the participant schools' interscholastic football teams

Exclusion Criteria:

• none

individual participant data (IPD) will not be made available to other researchers

statistician