The Effect of Exercise-Induced Central Fatigue and Concussion History on Cervical Spine Neuromuscular Function

This study provided a comprehensive investigation into the effect of exercise-induced central fatigue on head-and-neck neuromuscular function in subjects with and without concussion history.

Subjects were males between 18–50 years of age (mean=30 years), divided into two groups based on concussion history: 16 healthy males without a history of concussion and 16 males with a history of at least one concussion within their lifetime (range = 1–6), not within the last three months. Both groups underwent cervical joint position error, strength, and endurance testing concurrent with cervical spine electromyographic analysis, as well as King-Devick testing prior to and following an exhaustive fatiguing protocol.

Descriptive statistical results reveal no significant between-group differences for demographic characteristics. Variable families were adjusted for multiple comparisons via the holm correction. Fatigue effects were examined using 2(fatigued state) x 2(concussion history) mixed analysis of variance. There was a significant main effect for fatigued state in both groups for constant (p≤0.001, η_p²=0.48) and absolute (p≤0.001, η_p²=0.55) joint position error, neck flexor endurance test time (p≤0.001, η_p²=0.89), splenius capitis root mean square amplitude during cervical extension strength testing (p≤0.001, η_p²=0.42), sternocleidomastoid mean frequency during cervical rotation strength testing (p=0.019, η_p²=0.17), and King-Devick test time (p=0.009, η_p²=0.20). There were no significant between-group differences.

This study examined the influence of exercise-induced central fatigue on cervical spine neuromuscular function, emphasizing that athletes with and without concussion history are negatively impacted by fatigue. While no major differences were found between the groups, moderate to large effect sizes suggest that individuals with a history of concussion require varied neuromuscular responses and movement strategies to maintain performance versus their non-concussed counterparts. These findings indicate that a potential underlying vulnerability could elevate concussion risk particularly under fatigued conditions. This study underscores the need for further research with a larger sample size for higher powered group comparisons, more refined concussion history stratification, and increasingly sensitive outcomes.

Clinicians should consider the impact of exercise-induced central fatigue on cervical neuromuscular function, especially in athletes with concussion history. Concussion risk management approaches should address fatigue-related impairments, even when performance deficits are not apparent. Emphasizing cervical spine strengthening and neuromuscular control could be critical in reducing injury risk, particularly under fatigued conditions. Furthermore, regular assessments of neck function under fatigued conditions might help identify at-risk individuals and tailor interventions to enhance performance and safety.