Abdominal MusclesExercise TherapyLow Back PainTreatment OutcomeExercise TestExerciseExercise TolerancePhysical ExertionOxygen ConsumptionPhysical EnduranceMuscle, SkeletalHeart RateBicyclingRestPhysical FitnessTime FactorsResistance TrainingRunningAnaerobic ThresholdMuscle Stretching ExercisesPulmonary Gas ExchangeLactic AcidProtein StabilityBreathing ExercisesBlood PressurePhysical Education and TrainingLegAdaptation, PhysiologicalAsthma, Exercise-InducedRegional Blood FlowExercise Movement TechniquesOxygenMuscle StrengthGlycogenEnergy MetabolismWeight LiftingMuscle FatigueEnzyme StabilityHemodynamicsCardiac OutputAnalysis of VarianceRNA StabilityMuscle ContractionWalkingKineticsSportsRespirationErgometryRNA, MessengerCardiovascular Physiological PhenomenaMotor ActivityBlood GlucoseQuadriceps MuscleDyspnea