Electrical Stimulation of the Antagonist Muscle during Cycling Exercise Interval Training Improves Oxygen Uptake and Muscle Strength
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 VCE group (volitional cycle ergometer alone) (n=15). All subjects performed 30-min cycling exercise interval training sessions three times a week for six weeks.
The VO2peak of both groups significantly increased compared to the pre-training period (HCE group: from 31.3±4.4(ml/kg/min) pre-training to 37.6±6.7(ml/kg/min) post-training (P=0.0024), and VCE group: from 34.0±7.1(ml/kg/min) pre-training to 38.4±8.2 (ml/kg/min) (P=0.0057)). After the training, there was no significant difference of changes in VO2peak between the HCE and the VCE groups (P=0.7107). In the VCE group the maximal isokinetic torque of knee extension (60°/sec) post training did not significantly increase compared to the pre-training period (VCE group: from2.4±0.5 (Nm/kg) pre-training to 2.5±0.4 (Nm/kg) (P=0.4543)). In contrast, in the HCE group the maximal isokinetic torque of knee extension (60°/sec) post training significantly increased compared to pre-training period (HCE group: from 2.5±0.3 (Nm/kg) pre-training to 2.8±0.3 (Nm/kg) (P<0.0001)). The change in knee extension torque was significantly greater for the HCE group than for the VCE group. In conclusion, cardiopulmonary function and knee extension strength were improved by the use of HCE.