Neck strength and concussion in NCAA division I football
Purpose: Biomechanical analysis has indicated that concussions will occur secondary to linear and or rotational acceleration-deceleration changes of the head, as well as axial compression to the cervical spine. Researchers have revealed the importance of neck strength in force absorption rates with football players, but have failed to report any definitive relation between weak or untrained musculature and concussion. Through proper neck strengthing regimens, football athletes may train neck muscles to absorb potentially damaging changes in momentum associated with mild traumatic brain injury.
Methods: Twelve division I football athletes from Texas Tech University, who had sustained at least a grade one concussion in the last three years, were compared to twelve matched non-concussed football players based on height, weight, experience, and player position. Subjects’ weight charts containing six consecutive weeks of work out routines preceding concussion were analyzed. A normalized volume load (NVL) for each workout on the weight training days preceding concussion was compared between groups and individuals. The NVL data were compared between subjects and across weeks using a 2x6 mixed design ANOVA with repeated measures, and .05 was selected as the level of statistical significance.
Results: No statistically significant relations between the concussed and non-concussed participants (p>0.05) were observed. Descriptive statistics for the concussed versus non-concussed group mean + SD NVL were: WK1) 15.2+8.7 vs. 13.0+9.1; WK2) 18.8+8.9 vs. 15.9+6.8; WK3) 15.2+9.0 vs. 14.8+5.9; WK4) 15.0+9.3 vs. 13.6+7.5; WK5) 16.8+9.2 vs. 17.9+8.0; and WK6) 18.1+9.1 vs. 18.0+9.1. Week six (WK6) represents the week the concussion occurred. Eight of 12 concussed players were on defense. The concussed group consisted of four defensive backs (DBs), two linebackers, two defensive tackles, one wide receiver, two offensive linemen, and one long snapper. More concussions were observed in upper classmen (i.e., juniors and seniors), as would be expected due to a greater percentage of upper-class first string and starting players.
Conclusion: Comparisons of neck musculature training regimes, rather than actual strength measurements, may not be sufficient to identify a significant relation between training and concussion incidence. Future studies should directly measure neck strength, rather than rely on training records. Consistency in training protocols and comparison of concussion incidence between football programs that implement different training routines (e.g. periodization, isometric isolations, and power enhancing strength) should also be investigated. Future research may also measure cervical neck strength throughout the season as well as after concussion to identify any consistent periods of weakness that may correlate with periods of increased concussion incidence.