eng Science and Education Publishing American Journal of Sports Science and Medicine 2333-4606 2026-02-06 14 1 6 12 10.12691/ajssm-14-1-2 AJSSM20261412 article Aaron Thompson DrAaron.Thompson@keene.edu 1 Ava Fortin 2 Human Performance and Movement Science, Clinical Assistant Professor, Keene State College, Keene, USA Exercise Science, Student Research Assistant, Keene State College, Keene, USA This study examined sleep quality, neuromuscular performance, and perceived exertion in ultramarathon runners participating in events requiring completion of 100 miles during a multi-day ultramarathon. Eighteen participants completed pre-race data collection, which included a self-reported measure of sleep quality and baseline neuromuscular testing. Neuromuscular performance was assessed using hand grip strength, vertical jump height, and a functional sit-to-stand test. Following race completion, participants completed post-race neuromuscular testing and reported perceived exertion. Semi-structured interviews were conducted before and after the race to provide additional context related to fatigue, sleep, and recovery experiences. Descriptive analyses were used to examine changes in neuromuscular performance and participant-reported outcomes. Pre-race sleep quality varied across participants, with several individuals reporting poor sleep prior to competition. Among runners who completed post-race testing, declines in neuromuscular performance were commonly observed following completion of 100 miles, particularly in measures of lower-body power and functional performance, although the magnitude of change differed between individuals. Post-race perceived exertion scores ranged widely and did not consistently reflect the degree of observed neuromuscular impairment. Interview findings indicated that many participants viewed fatigue and physical discomfort as expected aspects of ultra-endurance running. These results suggest that runners completing 100 miles often begin competition with varied sleep quality and experience individual differences in neuromuscular fatigue that may not be fully captured by perceived exertion alone. Integrating objective performance measures with athlete-reported experiences may improve understanding of fatigue and recovery following ultra-endurance competition. https://pubs.sciepub.com/ajssm/14/1/2/ajssm-14-1-2.pdf ultramarathon running sleep quality neuromuscular performance perceived exertion functional fatigue