Evidence-based Intervention for Improved Head Impact Safety in Youth Football - Aim 1 and Aim 3

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) and quantified for practice sessions.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) and quantified for practice sessions. Number of impacts per player per minute

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) and quantified for practice sessions.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) and quantified for practice sessions.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of median linear acceleration.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of median rotational acceleration.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of median rotational velocity.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of 95th percentile linear acceleration.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of 95th percentile rotational acceleration.

Head impact data will be transformed to the head center of gravity using Matlab (Mathworks, Inc., Natick, MA) in terms of 95th percentile rotational velocity.

Perceived feasibility - higher values denote better feasibility - total range 0 - 5; 1, completely disagree; 5, completely agree - higher scores denote more possibility and agreeability to Intervention

total range 0 - 5 higher values denote better acceptability of the intervention (higher scores are better)

The intervention was prescribed to the North Carolina High School Athletic Association guidelines for contact in football practices, which limits teams to 15 minutes of live action contact per week. The percentage of practices the intervention was implemented as prescribed was monitored. An implementation score of 2 was given for adequate implementation (<15 minutes), 1 was given for partial implementation (<30 minutes), and 0 was given if live action contact exceeded 30 minutes for each practice. The percentage was calculated as the summed score for the season, divided by the maximum possible score across intervention teams.

Adaptations to the intervention will be tracked as the number of changes to the intervention during the football season. Coach initiated adaptions will be tracked via visual observation. Adaptations advised by the stakeholder team will be tracked via meeting notes.

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-1; lower scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores. Impulse control is a measure of errors on testing and is useful in determining test validity. This score indicates the sum of errors committed during different phases of the test - 0-40; lower scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 70-120; higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 70-120; higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - List Sorting Working Memory; the score range is 50-150 - higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - List Sorting Working Memory; the score range is 50-150 - higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - Picture Vocabulary - 70-120; higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - Picture Sequence Memory - 70-120; higher scores are better

Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - Picture Vocabulary - 70-120; higher scores are better

The RAVLT assesses verbal learning ability - A series of 15 words is presented to the participant 3 times via audio recording for standardization, and answers are recorded - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-45; higher scores are better

The RAVLT assesses verbal learning ability - A series of 15 words is presented to the participant 3 times via audio recording for standardization, and answers are recorded - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-45; higher scores are better

Participants will complete two 30-second trials (one with eyes opened, one with eyes closed) while standing on a force plate - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-50; lower scores are better

Participants will complete two 30-second trials (one with eyes opened, one with eyes closed) while standing on a force plate - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-50; lower scores are better

Participants will complete two 30-second trials (one with eyes opened, one with eyes closed) while standing on a force plate - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-10; lower scores are better

Participants will complete two 30-second trials (one with eyes opened, one with eyes closed) while standing on a force plate - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - 0-20; lower scores are better

The participant will be asked to focus on a small target that will be moved horizontally and vertically. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target that will be moved horizontally and vertically. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target and slowly bring it to the tip of their nose until two distinct images of the target are seen. The participant will complete this three times. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on two small targets that are horizontally aligned, moving their eyes quickly from one target to the other. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on two small targets that are horizontally aligned, moving their eyes quickly from one target to the other. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target and slowly bring it to the tip of their nose until two distinct images of the target are seen. The participant will complete this three times. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target that they are holding still while rotating their torso from side to side. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on two small targets that are vertically aligned, moving their eyes quickly from one target to the other. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on two small targets that are vertically aligned, moving their eyes quickly from one target to the other. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on one small target while rotating their head from side to side. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target that they are holding still while rotating their torso from side to side. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

The participant will be asked to focus on a small target and slowly bring it to the tip of their nose until two distinct images of the target are seen. The participant will complete this three times and scores will be averaged over three trials - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - Rates changes in symptoms on 0 - 15; lower scores are better

The participant will be asked to focus on a small target and slowly bring it to the tip of their nose until two distinct images of the target are seen. The participant will complete this three times and scores will be averaged over three trials - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - Rates changes in symptoms on 0 - 15; lower scores are better

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Reaction Speed; Raw reaction speed is the mean response speed for all non-perseverative responses made during the entire Test. Raw reaction speed is converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is atypically slow and <40 is atypically fast. Reaction speed is bi-directional with higher scores indicating slower reaction times (i.e., inattentiveness), and lower scores indicating faster reaction times (i.e., impulsivity)

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Omissions; Raw omissions scores are based on the number of missed targets during the test. Raw omissions scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very elevated and indicates poor performance. Higher scores indicate poorer performance

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Omissions; Raw omissions scores are based on the number of missed targets during the test. Raw omissions scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very elevated and indicates poor performance. Higher scores indicate poorer performance

Participants will complete a 14-minute computerbased assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Commission; Raw commissions are incorrect responses to non-targets. Raw commissions scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very conservative and indicates much emphasis on accuracy over speed and ≤30 is very liberal and indicates much emphasis on speed over accuracy. Scores indicate the nature of participants' response style rather than performance

Participants will complete a 14-minute computerbased assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Commission; Raw commissions are incorrect responses to non-targets. Raw commissions scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very conservative and indicates much emphasis on accuracy over speed and ≤30 is very liberal and indicates much emphasis on speed over accuracy. Scores indicate the nature of participants' response style rather than performance

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Perseverations; Raw perseverations are responses that are made in less than 100 milliseconds following a stimulus. Raw perseverations scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very elevated and indicates poor performance. Higher scores indicate poorer performance

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Perseverations; Raw perseverations are responses that are made in less than 100 milliseconds following a stimulus. Raw perseverations scores are converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is very elevated and indicates poor performance. Higher scores indicate poorer performance

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-1; lower scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores. Impulse control is a measure of errors on testing and is useful in determining test validity. This score indicates the sum of errors committed during different phases of the test - 0-40; lower scores are better

The Pattern Comparison Test is a measure of speed of processing, which typically improves steadily (time to complete task decreases) throughout childhood and adolescence, then begins to decline in adulthood, becoming much slower in older adults. As such, it is considered a "fluid ability" measure. Score range: 0-130

The Pattern Comparison Test is a measure of speed of processing, which typically improves steadily (time to complete task decreases) throughout childhood and adolescence, then begins to decline in adulthood, becoming much slower in older adults. As such, it is considered a "fluid ability" measure. Score range: 0-130

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

ImPACT is a computerized neuropsychological test battery. Participants will complete a pre-season baseline assessment which will be compared to post-season assessment scores - 0-100; higher scores are better

The participant will be asked to focus on one small target while rotating their head from side to side. The participant will report any symptoms (i.e., headache, dizziness, nausea, fogginess) after the task is complete. Symptoms reported range on a scale from 0-10; lower scores are better.

Participants will complete a 14-minute computer-based assessment that evaluates selective, sustained and divided attention, as well as impulsivity and vigilance - Participants will complete a preseason baseline assessment which will be compared to post-season assessment scores - CPT Reaction Speed; Raw reaction speed is the mean response speed for all non-perseverative responses made during the entire Test. Raw reaction speed is converted to standardized T-scores 0-90; 50 indicates the population mean with a standard deviation of 10. 70+ is atypically slow and <40 is atypically fast. Reaction speed is bi-directional with higher scores indicating slower reaction times (i.e., inattentiveness), and lower scores indicating faster reaction times (i.e., impulsivity).