Failure of endurance training to alter the cardiovascular response to static contraction

The purpose of this study was to determine whether endurance training alters the cardiovascular response to static contractions of the trained, but not untrained, musculature. Six healthy, untrained males (aged 23-36 years) underwent 10-12 weeks of intensive training involving both cycling and running. Peak VO2 on the bicycle ergometer, VO2max during graded treadmill running and concentrations of citrate synthase (CS) and malate dehydrogenase (MDH) in the vastus lateralis muscle were measured before and after training. Subjects performed static leg extension and forearm extension at 30% of maximal voluntary contraction until exhaustion before and after training. Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure were measured at rest, and in addition to perceived exertion (PE), every 30 s during contraction. Endurance training elicited significant increases in peak VO2 (36%), VO2max (32%), CS (25%) and MDH (42%) (all P less than 0.05). HR at rest was significantly lower (P less than 0.05) after training, while SBP and DBP were unchanged. HR, SBP, DBP and PE increased throughout both types of static contractions. However, the magnitude of the increases were unaffected by training. In contrast to recent findings, these results suggest that the increases in heart rate and blood pressure in response to static contraction are not altered after endurance training in either the trained or the untrained muscle groups.