Abstract
The purpose of this study was to investigate the cardiovascular response to upper and lower body static contraction in endurance-trained (ET) and untrained (UT) males (both groups N≈6). The groups were similar in age, height, and weight. However, the ET group exhibited a markedly higher (P < 0.01) V̇O2 max during treadmill running than the UT group (65.4 ± 4.8 vs 49.9 ± 2.8 ml · kg-1 min-1, mean ± SD). Both groups performed static handgrip and leg extension in a randomly assigned order at 30% of maximal voluntary contraction for 3 min. Heart rate and mean intraarterial blood pressure (MABP) were measured at rest and throughout contraction. At rest, differences between the two groups were not significant for heart rate (54 ± 10 vs 66 ± 8 beats · min-1) or MABP (93 ± 4 vs 91 + 5 mm Hg). During handgrip, the increases in heart rate (24 ± 12 vs 15 ± 6) and MABP (24 ± 10 vs 27 ± 12) were not significantly different between the two groups. During leg extension, the magnitude of the increases in heart rate (44 ± 21 vs 46 ± 27) and MABP (37 ± 11 vs 41 ± 10) were again not different for the two groups. These results suggest that cardiovascular regulation during static contraction is similar in endurance-trained and untrained individuals, even during contraction involving the trained musculature.
Key words
isometric exercise - intra-arterial blood pressure - endurance training
