Abstract
The effects of different types of acute bouts of resistance exercise on autonomic
modulation in individuals that are resistance-trained compared to untrained individuals
are unknown. Seventeen untrained and 17 resistance-trained participants were assessed
for autonomic modulation after various acute resistance exercise bouts. Electrocardiogram
readings were collected at rest and 25 min after a control period, whole-, lower-,
or upper-body acute bouts of resistance exercise. Heart rate variability and heart
rate complexity were used to assess autonomic modulation. Participants were similar
for age, height, weight and measures of body composition (p>0.05) and were different
for measures of maximal strength (p<0.05). There were no differences (p>0.05) in autonomic
modulation at rest between groups. Significant decreases (p<0.05) in parasympathetic
modulation after the acute bouts of resistance exercise were noted. Sample entropy
was not affected in the untrained group, but was significantly decreased after whole-
(−17.5%) and upper-body exercise (−13.5%) in the resistance training group. The changes
in sample entropy after lower-body resistance exercise were not significant (−15.7%;
p=0.06). These data suggest that resistance exercise training further attenuates the
parasympathetic responses to an acute bout of resistance training regardless of the
modality compared to the untrained state.
Key words
strength training - spectral analysis - sample entropy
