Date of Award
Master of Science
Alvaro N. Gurovich
Decrease of blood flow to tissues, due to atherosclerotic plaque formation, produces mortality and morbidity outcomes. Vascular homeostasis depends in the direct interaction between blood flow and endothelial cells, known as endothelial sheer stress (ESS). In addition, turbulent flow, which can be measured by Reynolds number (Re), has been associated with decrease ESS. Eccentric exercise (ECC) has gained attention as a novel exercise modality that increases muscle performance without increasing metabolic demands; however, little is known about ESS during ECC. PURPOSE: To determine the effects of ECC cycling in blood flow patterns and vascular reactivity in young, healthy individuals. METHODS: A total of 18 apparently healthy participants, were recruited for two laboratory visits. First visit served to obtain maximum oxygen consumption and peak power (PP), which will determine workload intensities, following by a 5-min familiarization on eccentric ergometer. Second visit on eccentric ergometer assessed blood flow patterns (i.e. ESS and Re measured via imaging ultrasound and Doppler, assessing brachial artery diameter and blood flow velicity) during a 3-workload steady exercise test at low (x% PP), moderate (y%PP), and high (z% PP) intensities. Third visit, at a moderate intensity on eccentric ergometer for 30-min duration, assessing Flow-Mediated Dilation (FMD) before and after bout of exercise as well as Venous Occlusion Plethysmography (VOP) to asses vascular reactivity. RESULTS: There was an interaction of exercise intensity on antegrade ESS (F(3,53.7)=26.90, p<0.001),but not Sex (p>0.05), and a random effect of participant (p < 0.001) and Re anterograde (F(3,53.6)=25.03, p<0.001), but not Sex or random effect of participant (p>0.05). There was an interaction of condition on retrograde ESS (F(3,53.4)=11.21, p<0.001),but not Sex (p>0.05), and a random effect of participant (p < 0.001). and Re retrograde (F(3,54.3)=12.34, p<0.001), Sex (F(1,18.5)=4.41, p=0.05), and random effect of participant (p>0.05). As well as no difference from pre to post on FMD (p>0.05). For VOP variables, there were significant changes with a moderate effect size in Upper Basal, Upper Ischemia (p<0.05), CONCLUSION: In conclusion, eccentric cycling exercise produces exercise-induced blood flow patterns that are intensity dependent, similar to traditional/concentric cycling. A single bout of ECC cycling produces an increase in blood flow in the upper extremity, associated with increased ESS, but not in the lower extremity.
Received from ProQuest
Gomez, Manuel, "Effects Of Eccentric Cycling On Blood Flow Patterns And Vascular Reactivity" (2022). Open Access Theses & Dissertations. 3681.