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Influence of weight training status on hemodynamic adjustments to isometric actions
1Department of Health and Exercise Science, Furman University, Greenville, South Carolina 29613, USA. tim.patrick@furman.edu
Background:
The purpose of this study was to investigate the hemodynamic adjustments to fatiguing isometric handgrip (IHG) performed at 20 and 60% of maximal voluntary contraction (MVC) in 10 weight-trained (WT, 4.8+/-1.6 yrs) and 8 untrained (UT) men.
Methods:
Hemodynamic measures were recorded at rest, during sustained IHG to fatigue, and during recovery. Blood pressures and heart rates (HR) were measured by auscultation and electrocardiography, respectively. Stroke volume (SV) was assessed by impedance cardiography. Mean arterial pressure (MAP), cardiac output (CO) and total peripheral resistance (TPR) were calculated.
Results:
Between group comparisons in peak hemodynamic adjustments (fatigue value-resting value) to IHG were analyzed across intensities by MANOVA and follow-up univariate tests. The peak adjustments in MAP, HR, and SV during IHG at 20 and 60% MVC were dependent on intensity (60%>20% MVC) but were not significantly different (p>0.05) between groups. However, the intensity-dependent, peak adjustments in CO (WT=1.17+/-1.2 L x min-1 vs UT= -0.40+/-1.7 L x min-1, p=0.005) and TPR (WT=4.4+/-6.1 PRU vs UT=10.2+/-8.3 PRU, p=0.02) were significantly different between groups across intensities of IHG.
Conclusions:
The results suggest that weight training does not significantly influence the pressor response but may significantly modify the adjustments in total-body circulation and vascular resistance during fatiguing IHG performed at 20 and 60% MVC.