Helma M de Morree

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It is a common observation that exertion of effort is associated with a specific facial expression. However, this facial expression has never been quantified during physical tasks and its relationship with effort is unknown. The aims of the present study were to measure frowning muscle activity during a physical task with electromyography (EMG) and to(More)
Locomotor muscle fatigue, defined as an exercise-induced reduction in maximal voluntary force, occurs during prolonged exercise, but its effects on cardiorespiratory responses and exercise performance are unknown. In this investigation, a significant reduction in locomotor muscle force (-18%, P < 0.05) was isolated from the metabolic stress usually(More)
It is thought that perception of effort during physical tasks is the conscious awareness of the central motor command sent to the active muscles. The aim of this study was to directly test this hypothesis by experimentally varying perception of effort and measuring movement-related cortical potential (MRCP). Sixteen healthy, recreationally active men made(More)
Caffeine intake results in a decrease in perception of effort, but the cortical substrates of this perceptual effect of caffeine are unknown. The aim of this randomized counterbalanced double-blind crossover study was to investigate the effect of caffeine on the motor-related cortical potential (MRCP) and its relationship with rating of perceived effort(More)
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