Similarity of Cardiovascular Response to Upper and Lower Body Static Contraction in Endurance-Trained and Untrained Males

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 less than 0.01) VO2 max during treadmill running than the UT group (65.4 +/- 4.8 vs 49.9 +/- 2.8 ml X kg-1 X 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 intra-arterial 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 X 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.