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

: To examine the effects of a 5-week continuous cycling training intervention on electromyographic amplitude (EMG)- and mechanomyographic amplitude (MMG)-torque relationships of the vastus lateralis (VL) during a prolonged contraction. : 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). Individual - (slopes) and -terms (y-intercepts) were calculated from the log-transformed electromyographic amplitude (EMG)- and mechanomyographic amplitude (MMG)-torque relationships during the increasing and decreasing segments of the trapezoid. EMG and MMG was normalized for the 45-s steady torque segment. : At PRE, -terms for the EMG-torque relationships during the linearly decreasing segment were greater than the increasing segment ( < .001), and decreased from PRE to POST ( = .027). -terms were greater during the linearly increasing than decreasing segment at PRE, while the -terms for the linearly decreasing segment increased from PRE to POST ( = .027). For the MMG-torque relationships, -terms during the linearly decreasing segment decreased from PRE to POST ( = .013), while -terms increased from PRE to POST when collapsed across segments ( = .022). Steady torque EMG increased for POST ( < .001). : 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) and mechanical output (MMG) to complete the same pre-training fatiguing contraction.