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

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.