Neck Strength Profiles Across Sports and Different Ages

Background: Sports-related concussion (SRC) is a relatively frequent injury, and can have significant morbidity for athletes. Avoiding repetitive SRC is worthwhile, especially for youth, and can prevent cumulative injuries to the brain. Developing cervical muscle strength is one way postulated to help prevent accumulation of repetitive SRC. We investigated cervical muscle strength in a cohort of predominantly high school athletes who had sustained a recent SRC and hypothesized there would be discernible differences between athletes of different ages, sex, size and sport played.

Methods: Athletes attending a specialty concussion clinic for baseline testing or evaluation after SRC were enrolled in a prospective investigation of their cervical muscle strength and endurance, and subsequent re-injury risk. Cervical strength was measured using two methods; (i) Gatherer System to assess peak force development in cervical flexion and extension (ii) Chin Tuck System to assess peak torque around an axis performing deep neck flexor activity and sustained torque endurance. Results were recorded for 3 trials of each test in each direction, and both the mean peak and the highest peak values noted. Welch 2 sample t-test comparison was performed between athletes presenting with SRC and athletes presenting at baseline, between male and females, between athletes of different age, height, weight and sport.

Results: 124 athletes <18 years old had a mean flexion neck strength of 29.4+/-11.5lb and a mean extension neck strength of 38.7+/-14.9lb. 49 athletes 18-26 years old had a mean flexion strength 37.6+/-13.4lb (p=0.0004) and a mean extension strength 49.0+/-18.3lb (p=0.0008). Collision sport high school athletes (14-18 year olds) had greater mean flexion (32.5+/-11.4lb versus 26.5+/-9lb, p=0.02) and extension strength (42.5+/-15.2lb versus 33.9+/-10.9lb, p=0.009) than athletes from limited contact sports. Limited contact high school athletes had greater cervical endurance (77.3+/-78.2 sec versus 44.2+/-38 sec, p=0.048) than collision sport athletes and lower cervical deep flexor torque (7.86+/-3.1Nm versus 10.2+/-4Nm, p=0.004).

Conclusion: We have demonstrated cervical muscle strength and deep neck flexor functional differences between contact sport level and age in the youth athletic population can be detected in a clinic setting using our testing methods. We believe that deep neck flexor function is more representative of protection against SRC than global neck strength and provide evidence in support of measurement of torque with a chin tuck as a potential target for SRC prevention strategies.