FatigueMuscle FatigueFatigue Syndrome, ChronicMental FatigueDelayed DiagnosisPrenatal DiagnosisEarly DiagnosisSensitivity and SpecificityDiagnosisRetrospective StudiesTreatment OutcomeTime FactorsSeverity of Illness IndexQuestionnairesQuality of LifeDiagnostic ErrorsProspective StudiesReproducibility of ResultsNeoplasmsMuscle, SkeletalMuscle ContractionFollow-Up StudiesTomography, X-Ray ComputedIsometric ContractionPredictive Value of TestsBiopsyRisk FactorsDiagnosis, Computer-AssistedFibromyalgiaSleep DisordersNursing DiagnosisDepressionPhysical EndurancePrognosisPainPrevalenceElectromyographyMagnetic Resonance ImagingCohort StudiesPreimplantation DiagnosisCase-Control StudiesChronic DiseasePolymerase Chain ReactionCross-Sectional StudiesAsthenopiaInfant, NewbornPregnancySurvivorsBreast NeoplasmsAge FactorsExerciseFatal OutcomeTorqueIncidenceBiopsy, NeedleDiaphragmComorbidityFetal DiseasesBiological MarkersUnited StatesSyndromeAcute DiseaseAnalysis of VarianceAnxietyMuscle StrengthPhysical ExertionPostpoliomyelitis SyndromeMultiple SclerosisLongitudinal StudiesPain MeasurementElectric StimulationNeurastheniaFractures, StressNeoplasm StagingDisease ProgressionROC CurveWork Schedule TolerancePsychometricsEnzyme-Linked Immunosorbent AssaySex FactorsFalse Positive ReactionsUltrasonography, PrenatalClinical Laboratory TechniquesSleepLogistic ModelsActivities of Daily LivingPsychiatric Status Rating ScalesFalse Negative ReactionsStress, PsychologicalRisk AssessmentTumor Markers, BiologicalQuadriceps MusclePilot ProjectsKneeExercise TestPhysical ExaminationLung NeoplasmsSurvival AnalysisRegression AnalysisExercise Therapy