Muscle FatigueMuscle, SkeletalMuscle ContractionFatigueMusclesMuscle Fibers, SkeletalMuscle ProteinsIsometric ContractionElectromyographyFatigue Syndrome, ChronicQuadriceps MuscleMental FatiguePhysical EnduranceMuscle DevelopmentRespiratory MusclesMuscle, SmoothAbdominal MusclesMuscle Fibers, Fast-TwitchExerciseMitochondria, MuscleMuscle Fibers, Slow-TwitchMuscle, Smooth, VascularElectric StimulationTorqueMuscle WeaknessMuscle StrengthPhysical ExertionMuscular DiseasesBackMuscle RelaxationDiaphragmMuscle DenervationSatellite Cells, Skeletal MuscleNeck MusclesTime FactorsMuscular AtrophyGlycogenLactic AcidIntercostal MusclesOxygen ConsumptionCalciumSarcoplasmic ReticulumElbow