Microvascular perfusion increases after eccentric exercise of the gastrocnemius.

ABSTRACT

OBJECTIVES: The purpose of this study was to assess microvascular perfusion immediately after eccentric exercise using contrast-enhanced sonography. METHODS: An intravenous catheter was placed in the antecubital vein of the arm contralateral to the leg being tested for the delivery of microbubbles to 18 healthy volunteers (mean age ± SD, 22.2 ± 2.2 years; height, 166.0 ± 11.9 cm; weight, 69.4 ± 25.0 kg). Eccentric exercises were performed unilaterally in a randomized leg. Calf-lowering repetitions off a raised step were performed to the beat of a metronome over 3 seconds in the sequence of 50 repetitions, 5 minutes of rest, and 50 repetitions. Microvascular perfusion (blood volume, blood flow, and blood flow velocity) was measured before and immediately after exercise using replenishment kinetics. RESULTS: Blood volume and flow both significantly increased after exercise (P < .001). Baseline measurements were 5.88 ± 1.33 dB and 2.34 ± 0.41 dB/s and increased to 12.20 ± 3.31 dB and 4.52 ± 1.05 dB/s, respectively. There was a significant decrease in blood flow velocity (P = .035) after exercise (0.38 ± 0.03 s(-1)) from baseline (0.41 ± 0.06 s(-1)). CONCLUSIONS: Circulatory responses were altered after eccentric exercise, which may be due to the metabolic demand placed on the body. On the basis of this finding, eccentric exercise may be used as a model to assess the effect modalities have on the circulatory system after an elevated state of microvascular perfusion is reached.