Mechanisms of neuromuscular fatigability in people with cancer-related fatigue

Callum G Brownstein, Rosemary Twomey, John Temesi, Mary E Medysky, S. Nicole Culos-Reed, Guillaume Y Millet*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Cancer-related fatigue (CRF) is a debilitating symptom that affects around one-third of people for months or years after cancer treatment. In a recent study, we found that people with post-treatment CRF have greater performance fatigability. The aim of this secondary analysis was to examine the aetiology of performance fatigability in people with post-treatment CRF.
Ninety-six people who had completed cancer treatment were dichotomized into two groups (fatigued and non-fatigued) based on a clinical cut-point for fatigue. Alterations in neuromuscular function (maximal voluntary contraction peak force, MVC; voluntary activation, VA; potentiated twitch force, Qtw,pot; electromyography, EMG) in the knee extensors were assessed across three common stages of an incremental cycling test. Power outputs during the fatigability test were expressed relative to gas exchange thresholds to assess relative exercise intensity.
The fatigued group had a more pronounced reduction in MVC peak force and Qtw,pot throughout the common stages of the incremental cycling test (main effect of group: p < 0.001, ηp2 = 0.18 and p = 0.029, ηp2 = 0.06, respectively). Electromyography was higher during cycling in the fatigued group (main effect of group: p = 0.022, ηp2 = 0.07). Although the relative intensity of cycling was higher in the fatigued group at the final common stage of cycling, this was not the case during the initial two stages, despite the greater impairments in neuromuscular function.
Our results suggest that the rapid impairments in performance fatigability in people with CRF was primarily due to disturbances at the level of the muscle, rather than the central nervous system. This could impact the ability to tolerate daily physical activities.
Original languageEnglish
JournalMedicine & Science in Sports & Exercise
Early online date8 Apr 2022
Publication statusE-pub ahead of print - 8 Apr 2022


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