FatigueMuscle FatigueFatigue Syndrome, ChronicMental FatigueMuscle ContractionMuscle, SkeletalIsometric ContractionQuality of LifePhysical EnduranceSeverity of Illness IndexQuestionnairesSleep DisordersFibromyalgiaElectromyographyAsthenopiaDepressionPainNeoplasmsTorqueTreatment OutcomeExerciseTime FactorsDiaphragmMuscle StrengthPhysical ExertionPostpoliomyelitis SyndromeElectric StimulationNeurastheniaWork Schedule ToleranceSurvivorsQuadriceps MuscleSleepMultiple SclerosisMaterials TestingFractures, StressAnxietyKneePain MeasurementExercise TherapyChronic DiseaseDisorders of Excessive SomnolenceStress, MechanicalActivities of Daily LivingExercise ToleranceBiomechanical PhenomenaAnalysis of Variance