Resumen de Electrical Stimulation of the Antagonist Muscle During Cycling Exercise Interval Training Improves Oxygen Uptake and Muscle Strength

Ryuki Hashida, Yoshio Takano, Hiroo Matsuse, Mei Kudo, Masafumi Bekki, Masayuki Omoto, Takeshi Nago, Takumi Kawaguchi, Takuji Torimura, Naoto Shiba

• A hybrid training system (HTS) is a resistance exercise method that combines voluntary concentric muscle contractions and electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on cycle ergometer (HCE). The purpose of this study was to compare cardiorespiratory function and muscle strength when cycling exercise is combined with electrical stimulation over an extended period. Twenty-nine healthy young men were divided into an HCE group (n = 14) and a volitional cycle ergometer (VCE alone) group (n = 15). All subjects performed 30-minute cycling exercise interval training sessions 3 times a week for 6 weeks. The V[Combining Dot Above]O2peak of both groups significantly increased compared with the pretraining period (HCE group: from 31.3 +/- 4.4 [ml[middle dot]kg-1[middle dot]min-1] pretraining to 37.6 +/- 6.7 [ml[middle dot]kg-1[middle dot]min-1] post-training [p = 0.0024] and VCE group: from 34.0 +/- 7.1 [ml[middle dot]kg-1[middle dot]min-1] pretraining to 38.4 +/- 8.2 [ml[middle dot]kg-1[middle dot]min-1] [p = 0.0057]). After the training, there was no significant difference of changes in V[Combining Dot Above]O2peak between the HCE and the VCE groups (p = 0.7107). In the VCE group, the maximal isokinetic torque of knee extension (60[degrees][middle dot]s-1) post-training did not significantly increase compared with the pretraining period (VCE group: from 2.4 +/- 0.5 [N[middle dot]m[middle dot]kg-1] pretraining to 2.5 +/- 0.4 [N[middle dot]m[middle dot]kg-1] [p = 0.4543]). By contrast, in the HCE group, the maximal isokinetic torque of knee extension (60[degrees][middle dot]s-1) post-training significantly increased compared with pretraining period (HCE group: from 2.5 +/- 0.3 [N[middle dot]m[middle dot]kg-1] pretraining to 2.8 +/- 0.3 [N[middle dot]m[middle dot]kg-1] [p < 0.0001]). The change in knee extension torque was significantly greater for the HCE group than for the VCE group (p = 0.0307). In conclusion, cardiopulmonary function and knee extension strength were improved by the use of HCE.