We have previously shown an association between ncck injury and disturbed jaw function. This study tested the hypothesis of a relationship between neck injury and impaired endurance during chewing. Fifty patients with whiplash-associated disorders (\VAD) were compared with 50 tcmporomandibular disorders (TMD) patients and 50 healthy subjects. Endurance was evaluated during unilateral chewing of gum for 5 min when participants reported fatigue and pain. Whereas aH healthy suhjects complcted the task, 1/4 of the TMD and a majority of the \VAD patients discontinued the task. A majority of the WAD patients also reported fatigue and paln. These ndings suggest an association between neck injury and reduced functional capacity of the jaw motor system. From the results, we propose that routinc cxamination of ‘VAD patients should include jaw function and that an endurance test as described in this study could also be a useful tool for nondental professionals.