Honors Theses

Date of Award


Document Type

Undergraduate Thesis

Degree Name



Biomedical Sciences

Faculty Mentor

Ryan J. Colquhoun


Neil A. Schwarz, Caitlyn M. Meehan


High-load resistance training (>70% 1 repetition maximum (RM)) is commonly believed to be the superior method for producing neuromuscular adaptation with a resistance exercise program. Recent research has shown that lower-load resistance training (<50% 1RM) could produce similar responses when taken to failure. However, nearly all the existing research has been completed in males, making it unclear if this holds true across sexes. The purpose of this investigation, therefore, was to examine sex-differences in neuromuscular function and fatigue following acute bouts of high- vs low-load unilateral leg extension taken to volitional failure. Twenty-nine (16 females) resistance-trained subjects completed unilateral high-load (HL) and low-load (LL) resistance exercise bouts. The condition and leg utilized for the first visit was randomized and the opposite condition was completed on the other leg 24 hours (±1 hr.) after the first session. Surface electromyography (EMG) of quadriceps, exercise performance, and rating of perceived exertion (RPE) were measured during each visit. The present data suggests a more pronounced accumulation of fatigue in the muscle throughout LL, as indicated by greater reductions in repetitions completed with each set and more pronounced reductions in EMG median power frequency (EMGMDF). Despite similar patterns of EMG amplitude (EMGAMP) across the exercise bouts, the present data suggest that HL produced significantly greater muscle excitation than LL when collapsed across all other factors. Overall, males completed more repetitions across sets and during each condition when compared to females. Consequently, males also reported a greater set RPE/repetitions in reserve (RPE/RIR) and session RPE (sRPE).


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