The Effect of Exercise-Induced Central Fatigue on Cervical Spine Joint Position Error, Strength, and Endurance.

The concussion-history group had only five people and was exploratory, not used for hypothesis testing. The study did not compare the healthy and concussion-history groups statistically, so it cannot say how much prior concussion changes fatigue effects. The authors say there is no direct evidence linking central fatigue to increased concussion risk. No head-and-neck movement analysis was done, so the study cannot show how fatigue changes actual head motion during impacts. The strength test only recorded peak force, not muscle activation or motor control, and participants often appeared to struggle more despite small measured strength changes. The authors found no clear physiological reason why only flexion strength decreased in healthy adults and said it could be chance or undetected error.

The authors report no conflicts of interest.

Do not read the larger neck position errors after fatigue as proof that fatigue causes concussion. The study did not measure impacts or concussion outcomes, and the five people with prior concussions were too few for a statistical comparison.