Muscular Performance and Hemodynamic Responses to Circuit and Traditional Resistance Training at Different Intensities: A Randomized Crossover Study

Abstract

This study compared the acute effects of circuit and traditional resistance training (RT) performed at different intensities on muscular performance and hemodynamic responses. Ten resistance-trained men (25.8±4.3 years, BMI: 24±2.3 kg/m², RT experience: 4.3±2.5 years) completed four randomized protocols: high-intensity circuit (HC), moderate-intensity circuit (MC), high-intensity traditional (HT), and moderate-intensity traditional (MT). Each protocol was performed twice, once for muscular performance and once for cardiovascular assessment. Sessions involved two sets of bench press and leg press performed at either 80% or 60% one-repetition maximum (1RM). Hemodynamic data were rank-transformed using the aligned rank transform for factorial analysis of main effects and interactions, while muscular and perceptual responses were analyzed using repeated measures ANOVA or Friedman tests, followed by appropriate post-hoc comparisons and effect sizes (ES). Systolic blood pressure (p<0.001, large ES), heart rate (p<0.001, very large ES), and rate-pressure product (p<0.001, very large ES) increased significantly post-exercise across all conditions and remained elevated at 10 min (p<0.001, large–very large ES). No post-exercise hypotension was observed. Maximum repetitions and total load lifted were greater at moderate intensity (p<0.0001, large ES), accompanied by lower ratings of fatigue (p<0.0001, large ES). No significant differences were found between circuit and traditional structures. High-intensity protocols, regardless of structure, elicited greater cardiovascular stress and fatigue, whereas moderate-intensity RT enhanced performance with lower physiological strain. These results highlight exercise intensity as the primary determinant of acute cardiovascular and muscular responses.