Cardiovascular Responses in High, Moderate and Low Aerobic Capacity Males During Static and Dynamic Work.

Abstract

Eighteen male subjects participated in an investigation to examine the effects of static, dynamic, and combination work (static and dynamic) on the variables heart rate, systolic and diastolic blood pressure, pressure rate product, and maximal oxygen consumption (VO(,2)(' )max). The subjects, who were all free from any cardiovascular problems, were divided into 3 groups based on their maximum oxygen consumption levels. The high (Group 1), moderate (Group 2), and low (Group 3) aerobic capacity groups had mean VO(,2)(' )max levels of 64, 55, and 47 ml(.)kg('-1)(.)min('-1), respectively. Each subject performed a static test (holding a weighted brief case), a dynamic test (walking on a treadmill) and a combination test (holding a weighted brief case while walking on a treadmill). Workloads for all subjects were relative to their VO(,2)(' )max level and to their maximum voluntary contraction. In addition to the static test, dynamic test, and the combination test, which were counter-balanced to prevent any ordering effect, the subjects also performed two maximal treadmill tests in order to observe whether static contractions during maximal work would increase VO(,2)(' )max. The first was a standard dynamic treadmill test while the second followed the same protocol with the addition of a static component during the last 2 minutes. Statistical analysis (MANOVA, ANOVA, Duncan's Multiple Range Test) revealed that aerobic fitness level did not affect the heart rate, blood pressure, or pressure-rate product response to the three types of work examined. Furthermore, VO(,2)(' )max was not increased by the addition of static work during a maximal test. Heart rate and pressure rate product were significantly higher (p < .05) during combination work than during dynamic work, and during dynamic work they were significantly higher than during static work. Diastolic blood pressures were significantly different across all three modes of work. Ordered from high to low, they were static work, combination work, and dynamic work. Systolic blood pressure was significantly higher for combination work, but measures taken during static and dynamic work were not significantly different.