Objective: To evaluate the effects of exercise-induced, subjectively assessed muscle fatigue on an inhibitory jaw reflex, evoked by electrical stimulation of the upper lip. In addition, the reproducibility of these effects was assessed.
Design: Eight subjects participated in two experimental sessions that were two weeks apart. During each session, a baseline recording, a post-conditioning recording, and two recovery recordings were obtained. The post-conditioning recording was obtained immediately after provocation of jaw muscle fatigue by intense chewing. The endpoint of provocation was reached 30 s after a subject had crossed the value '6' on a 10 cm long visual analogue scale.
Results: Subjectively assessed jaw muscle fatigue caused a decrease of about 50% in the size of the late inhibition in the post-conditioning recording (ANOVA: p = 0.001; Bonferroni contrasts: p<0.05). Full recovery to baseline values was already achieved at the first recovery recording. No significant differences were found between both sessions (ANOVA, p = 0.677).
Conclusion: Exercise-induced, subjectively assessed jaw muscle fatigue causes a reproducible, transient suppression in the size of the late inhibitory jaw reflex wave. (C) 2009 Elsevier Ltd. All rights reserved.
- Jaw muscle
- Jaw reflex
- EXTEROCEPTIVE SUPPRESSION
- CRANIOMANDIBULAR DISORDERS
- INTRAORAL SITES
- NOXIOUS STIMULI
- CLOSING MUSCLES