Neural Efficiency Under Load: Mapping Motor Unit Recruitment Ceilings in Advanced Strength-Trained Athletes

Background: Long-term resistance training induces profound neural adaptations that extend beyond initial rapid gains. The nature of these adaptations appears highly specific to the training stimulus (maximal strength vs explosive power). Objective: This cross-sectional investigation quantified motor unit recruitment ceilings and rate coding characteristics in elite powerlifters, elite Olympic weightlifters, and advanced recreational controls during progressive isometric loading. Methods: Forty male athletes performed trapezoidal isometric knee-extension ramps with high-density surface EMG decomposition to define recruitment ceiling and discharge characteristics. Results: Significant group differences were observed across recruitment ceiling and high-threshold discharge rate patterns, with weightlifters showing lower recruitment ceiling but higher discharge rates, indicating distinct neural strategies optimized for power expression.