State Anxiety and the Hoffmann Reflex Following Selected Forms of Acute Exercise

Abstract

1996 There is considerable evidence that acute physical activity is associated with improvements in various measures of mood and with reduced state anxiety. Other research has focused on biological correlates of anxiety, including the soleus Hoffmann reflex (H-reflex). The H-reflex is a common measure of motoneuron excitability, specifically, the magnitude and latency of the reflex response of the muscle to stimulation of the innervating nerve. However, very few investigations have examined the influence of acute exercise on biological variables implicated in mood and state anxiety concomitantly. PURPOSE: The purpose of this study was to identify whether soleus H-reflex changes were associated with state anxiety changes following acute bouts of aerobic or resistance exercise. METHODS: Thirty-two physically active participants (16 Males, 16 Females; mean age = 22.16 years, SD = 2.65 years) were assessed on baseline soleus H-reflex recruitment curves and completed state anxiety (STAI-Y1) measures prior to 30-min of resistance training or cycle ergometry at a self-selected intensity. RESULTS: Post-exercise assessments of soleus H-reflex and state anxiety were taken immediately and at 45 and 90 minutes after exercise cessation. Repeated measures ANOVA revealed a significant (p<0.05) trial effect for state anxiety and H-reflex. Post hoc analysis indicated a significant (p<0.05) 9% reduction in state anxiety by the 45-minute post-exercise follow-up, and a 13.5% reduction by the 90-minute post-exercise follow-up. H-reflex was significantly reduced (p<0.05) by 9% for the bicycle ergometry condition at the immediate post-exercise follow-up, but subsequent assessments did not differ from baseline. No changes in H-reflex were observed following resistance training. Correlational analysis revealed that state anxiety values were not associated (r = 0.04, p>0.05) with H-reflex measures. CONCLUSION: The independence of the H-reflex and state anxiety responses to exercise sessions suggests that the H-reflex may not be a sound physiological correlate to state anxiety. This conclusion is further reinforced by the failure to observe a significant correlation between these two variables. In summary, these results do not support an H-reflex mediated tranquilizer explanation of exercise induced mood change.