BackElectromyographyMuscle, SkeletalLumbosacral RegionPostureTorsoAbdominal MusclesNeck MusclesMuscle FatigueLow Back PainBiomechanical PhenomenaMuscle ContractionPostural BalanceMusclesLumbar VertebraeMovementMuscle ProteinsMuscle, SmoothPseudomonadaceaeRoseobacterMuscle Fibers, SkeletalMuscle, Smooth, VascularMuscle DevelopmentSpineMuscle Fibers, Fast-TwitchMuscle DenervationMuscle Fibers, Slow-TwitchMyocytes, Smooth MuscleMitochondria, MuscleOculomotor MusclesMuscle, StriatedMuscle SpindlesMuscle RelaxationRespiratory MusclesMuscle WeaknessPapillary Muscles