Is fatigue after a stroke associated with physical de-conditioning? A cross-sectional study in ambulatory stroke survivors

Aims to determine the relationship between a measure of fatigue and 2 indices of physical fitness, lower limb extensor power (LLEP) and walking economy. Design: This was a cross-sectional study of patients with stroke. Fatigue was assessed by vitality (VIT) score of the Medical Outcomes Study 36-Item Short-Form Health Survey version 2 (SF-36v2). LLEP of the unaffected limb was measured using a lower leg extensor power rig. Walking economy was calculated by measuring oxygen consumption (mL·kg–1·m–1) during walking at a comfortable speed. Bivariate analyses were performed relating VIT to indices of fitness. Multiple regression analyses were also performed and included age, sex, and either SF-36v2 emotional role function or SF-36v2 mental health, as predictors of VIT.Setting: Community setting.Participants: Participants (N=66; 36 men; mean age ± SD, 71.0±9.9y) were all community dwelling, had survived a stroke, were able to walk independently, and had completed their stroke rehabilitation. The main outcome measure is SF-36v2 (VIT), with walking economy and LLEP of the limb unaffected by the stroke being independent variables. Results: Walking economy was not significantly related to VIT (R=–.024, P=.86, n=60). LLEP was positively related to VIT in bivariate analysis (R=.38, P=.003, n=58). After controlling for age, sex, and SF-36 emotional role function (or SF-36v2 mental health if the extreme outlier was excluded), LLEP remained a significant predictor of VIT. Conclusions: We found an association between fatigue and reduced LLEP. If a larger study confirms these findings, it would support the need to develop and test interventions to increase LLEP as a treatment for fatigue after stroke.