Abstract
Abstract Purpose Electrical stimulation-induced muscle contractions in individuals with paralyzed muscles are often associated with early onset fatigue. We examined whether electrical stimulation (ES) of the quadriceps muscle results in vasoconstriction and a reduction in blood flow which may contribute to this early onset fatigue. Methods Seventeen young individuals completed 40 ES isometric contractions (stimulation frequency of 75 Hz, pulse duration of 400 μs, on-off ratio 6.0-20s) and force matched voluntary (VOL) isometric contractions. Isometric force, heart rate, blood pressure, superficial femoral diameter and blood velocity were measured at baseline and during exercise (contractions 1,5,10,15,20,25,30,35, and 40). Net, antegrade, and retrograde blood flow, and conductance were quantified. Two-way, within-subjects ANOVAs were used to evaluate diameter, blood flow and conductance. Results Diameter was not different between ES and VOL (p = 0.57). Net blood flow increased during both conditions with the greatest blood flow occurring during ES compared to VOL (p ≤ 0.01). ES showed a greater increase antegrade and reduced retrograde flow compared to VOL. After the twentieth contraction, ES also elicited greater conductance than VOL (p ≤ 0.049). Conclusion The use of neuromuscular electrical stimulation to elicit muscle contractions does not result in vasoconstriction or a reduced hyperemic response compared to volitional contractions.
Published Version
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