B T Patrick1, A Caterisano. 1. Department of Health and Exercise Science, Furman University, Greenville, SC 29613, USA. tim.patrick@furman.edu
Abstract
AIM: We attempted to isolate the effects of central command (CC) and the muscle metaboreflex (MR) on hemodynamics during and following fatiguing isometric handgrip (IHG) with circulatory arrest in 9 male weightlifters (WL) and 11 age-matched controls (C). METHODS: Hemodynamics were recorded at rest, during fatiguing IHG at 40% MVC with occlusion, and during post-IHG occlusion. Blood pressures were measured by auscultation and stroke volume by impedance cardiography. RESULTS: Hemodynamic adjustments due to CC were determined from the difference (fatigue post-IHG occlusion) in measures at fatigue during IHG (CC+MR effects) and during post-IHG occlusion (MR effect). Hemodynamic adjustments due to the MR were determined from the difference (post-IHG occlusion rest) in measures during post-IHG occlusion and at rest. The peak adjustment (due to CC+MR) in systolic blood pressure (44.6+/-12.9 vs 33.8+/-6.2 mmHg, P=0.02) and the adjustments (due to CC) in diastolic (13.8+/-7.6 vs 6.9+/-5.1 mmHg, P=0.02) and mean arterial blood pressures (14.9+/-7.8 vs 8.7+/-4.6 mmHg, P=0.04) were significantly greater in WL than C. However, there were no significant (P>0.05) group differences in hemodynamic adjustments (due to MR) to post-IHG occlusion. CONCLUSION: We conclude that weight training may result in significantly greater CC effects on peak pressor responses to moderately intense, fatiguing isometric actions with circulatory arrest.
AIM: We attempted to isolate the effects of central command (CC) and the muscle metaboreflex (MR) on hemodynamics during and following fatiguing isometric handgrip (IHG) with circulatory arrest in 9 male weightlifters (WL) and 11 age-matched controls (C). METHODS: Hemodynamics were recorded at rest, during fatiguing IHG at 40% MVC with occlusion, and during post-IHG occlusion. Blood pressures were measured by auscultation and stroke volume by impedance cardiography. RESULTS: Hemodynamic adjustments due to CC were determined from the difference (fatigue post-IHG occlusion) in measures at fatigue during IHG (CC+MR effects) and during post-IHG occlusion (MR effect). Hemodynamic adjustments due to the MR were determined from the difference (post-IHG occlusion rest) in measures during post-IHG occlusion and at rest. The peak adjustment (due to CC+MR) in systolic blood pressure (44.6+/-12.9 vs 33.8+/-6.2 mmHg, P=0.02) and the adjustments (due to CC) in diastolic (13.8+/-7.6 vs 6.9+/-5.1 mmHg, P=0.02) and mean arterial blood pressures (14.9+/-7.8 vs 8.7+/-4.6 mmHg, P=0.04) were significantly greater in WL than C. However, there were no significant (P>0.05) group differences in hemodynamic adjustments (due to MR) to post-IHG occlusion. CONCLUSION: We conclude that weight training may result in significantly greater CC effects on peak pressor responses to moderately intense, fatiguing isometric actions with circulatory arrest.