Neuromuscular fatigue is defined as an exercise-induced reduction in producing force or power from a muscle or muscle group. The origins of exercise-induced fatigue can occur anywhere in the motor system – from the brain all the way through to the muscle. Therefore, to assess central and peripheral mechanisms of fatigue, investigators must be acutely aware of what their chosen fatigue measures actually reveal about the motor system. Although stimulation techniques such as transcranial magnetic stimulation (TMS) provide excellent insight into neuromuscular fatigue, they are mostly inappropriate to use in field settings and clinical environments. Instead, a practical way of assessing fatigue in these environments is to obtain self-reported assessments of fatigue, which may be in the form of fatigue and exertion scales. To date, there have been surprisingly few investigations that assess the relationship between quantifiable measures of motor fatigue and self-reported fatigue scales. [...]