Extraordinary Fast-Twitch Fiber Abundance in Elite Weightlifters

摘要: ABSTRACT Human skeletal muscle fibers exist across a continuum of slow → fast-twitch. The amount each fiber type (FT) influences performance but remains largely unexplored in elite athletes, particularly from strength/power sports. To address this nescience, vastus lateralis (VL) biopsies were performed on World/Olympic (female, n=6, “WCF”) and National-caliber n=9, “NCF”; male, “NCM”) American weightlifters. Participant accolades included 3 Olympic Games, 19 World Championships, 25 National records, >170 National/International medals. Samples analyzed for myosin heavy chain (MHC) content via SDS-PAGE using two distinct techniques: single (SF) distribution (%) homogenate (HG) composition. These athletes displayed the highest MHC IIa concentrations ever reported healthy VL (23±9% I, 5±3% I/IIa, 67±13% IIa, 6±10% IIa/IIx), with WCF expressing notable 71±17% (NCF=67±8%, NCM=63±16%). heavyweights accounted 91% IIa/IIx fibers. When compared to SF, HG overestimated I (23±9 vs. 31±9%) IIx (0±0 3±6%) by misclassifying I/IIa as IIx. findings suggest athlete caliber (World National), training experience, body mass determine FT% more than sex refutes common pronouncement that women possess fewer fast-twitch men. Our results also show abundance pure rarity strength/power-trained indicate potential link between frequency mass, question fidelity measure distribution. extreme partially explains how weightlifters generate high forces rapid time-frames. data highlight need cellular molecular research anaerobic athletes.