High-Intensity Cycling Training Necessitates Increased Neuromuscular Demand of the Vastus Lateralis During a Fatiguing Contraction.

Purpose : To examine the effects of a 5-week continuous cycling training intervention on electromyographic amplitude (EMG RMS )- and mechanomyographic amplitude (MMG RMS )-torque relationships of the vastus lateralis (VL) during a prolonged contraction. Methods : Twenty-four sedentary, young adults performed maximal voluntary contractions (MVCs) and a prolonged isometric trapezoidal contraction at the same absolute 40% MVC for the knee extensors before (PRE) and after training (POST ABS ). Individual b - (slopes) and a -terms (y-intercepts) were calculated from the log-transformed electromyographic amplitude (EMG RMS )- and mechanomyographic amplitude (MMG RMS )-torque relationships during the increasing and decreasing segments of the trapezoid. EMG RMS and MMG RMS was normalized for the 45-s steady torque segment. Results : At PRE, b -terms for the EMG RMS -torque relationships during the linearly decreasing segment were greater than the increasing segment ( p  < .001), and decreased from PRE to POST ABS ( p  = .027). a -terms were greater during the linearly increasing than decreasing segment at PRE, while the a -terms for the linearly decreasing segment increased from PRE to POST ABS ( p  = .027). For the MMG RMS -torque relationships, b -terms during the linearly decreasing segment decreased from PRE to POST ABS ( p  = .013), while a -terms increased from PRE to POST ABS when collapsed across segments ( p  = .022). Steady torque EMG RMS increased for POST ABS ( p  < .001). Conclusion : Although cycling training increased aerobic endurance, incorporating resistance training may benefit athletes/individuals as the alterations in neuromuscular parameters post-training suggest a greater neural cost (EMG RMS ) and mechanical output (MMG RMS ) to complete the same pre-training fatiguing contraction.