<p>he purpose of this investigation was to examine possible differences in the acute systemic arterial blood pressure and esophageal pressure and left ventricular function responses to various intensities of static-dynamic and isometric single-leg press and cycle ergometry exercise. Intra-arterial blood pressure, intra-esophageal pressure and left ventricular function were measured in eight subjects (mean age: 23 years) during 6 and 12 repetitions of static-dynamic single-leg press at 70% (SLP70) and 90% (SLP90) of the subjects's 1 repetition maximum (l RM) respectively, 30 seconds of isometric single-leg press exercise at 70% (ILP70) and 90% (ILP90) of maximum capacity and during 60 seconds of steady state cycle ergometry at 70 % of maximum power output (MPO) (CE70). ILP70 produced significantly greater (p < 0.05) circulatory responses (arterial blood pressure, esophageal pressure, heart rate and rate-pressure product) than SLP70. CE70 produced greater (p < 0.05) peak mean (PM) systolic blood pressure (PMSBP), heart rate (PMHR) and rate-pressure product (PMRPP) than either ILP70 and SLP70 but had similar PM diastolic blood pressure (PMDBP), mean arterial blood pressure (PMAP) and esophageal pressure (PMEP) to SLP70. SLP90 and ILP90 for the same absolute time period produced similar cardiovascular responses as did ILP90 and ILP70. Greater (p < 0.05) rates of increase and PM responses were found to occur during SLP90 than during SLP70. Differences in response to SLP70 and ILP70 may be due to the greater: duration of active muscle contraction, esophageal pressure (due to the Valsalva maneuver), occlusion of the vascular beds in the exercising muscles and degree of effort associated with ILP70. CE70 produced greater (p < 0.05) PMSBP, PMHR and PMRPP responses due to a greater cardiac output known to occur with this form of exercise. The increased HR and stroke volume (SV) and decreased total peripheral resistance (TPR) would be expected to result in the greater PMSBP and unchanged PMDBP which were observed. The similar circulatory responses during SLP90 and ILP90 appear to be linked to comparable increases in intra- esophageal pressure from enlisting of the Valsalva maneuver and similar amounts of effort required to perform these exercises.</p> / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/12157 |
| Date | 10 1900 |
| Creators | Lentini, Anthony C. |
| Contributors | McCartney, Neil, Human Biodynamics |
| Source Sets | McMaster University |
| Detected Language | English |
| Type | thesis |
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