Chapter 21Chapter 21pp. 435pp. 435--436436Delayed Onset Muscle Delayed Onset Muscle SorenessSorenessMuscle SorenessMuscle SorenessDelayed onset Delayed onset muscle soreness muscle soreness (DOMS)(DOMS)––Appears 24Appears 24--48 hours 48 hours after strenuous after strenuous exerciseexercise––Due to microscopic Due to microscopic tears in muscle tears in muscle fibers resulting in fibers resulting in inflammatory inflammatory responseresponseFig 21.4Muscular SorenessMuscular SorenessTypesTypes––AcuteAcute--within 24 hourswithin 24 hours––Chronic (delayed)Chronic (delayed)--2424--48 hours48 hoursAcuteAcute--during/immediately following exerciseduring/immediately following exercise––Causes: ischemiaCauses: ischemia--lack of adequate blood flowlack of adequate blood flow––1. Muscular pain is produced during contractions in 1. Muscular pain is produced during contractions in which tension causes ischemiawhich tension causes ischemia––2. Metabolic waste products cannot be removed and 2. Metabolic waste products cannot be removed and stimulate pain receptorsstimulate pain receptorsMuscular SorenessMuscular Soreness––3. Pain is reduced when contraction intensity 3. Pain is reduced when contraction intensity is decreased or accumulated lactic acid is is decreased or accumulated lactic acid is removedremovedDelayed Muscular SorenessDelayed Muscular SorenessPain and soreness that occurs 24Pain and soreness that occurs 24--48 48 hours post exercisehours post exerciseMuscle soreness is related to type of Muscle soreness is related to type of muscular contraction performedmuscular contraction performed––Eccentric contraction causes greater muscle Eccentric contraction causes greater muscle soreness than isotonic (concentric) soreness than isotonic (concentric) contractionscontractionsTheories for DOMSTheories for DOMSTorn tissue theoryTorn tissue theory––Tissue damage Tissue damage ––structural damage in musclestructural damage in muscleConnective tissue theoryConnective tissue theory––Connective tissues are damaged during contractionConnective tissues are damaged during contractionHydroxyprolineHydroxyprolineis a product of connective tissue breakdownis a product of connective tissue breakdownMeasured in urineMeasured in urineResearch has shown significant correlations between Research has shown significant correlations between maximal maximal hydroxyprolinehydroxyprolineexcretion and time of greatest excretion and time of greatest soreness sorenessTheories for DOMSTheories for DOMSCalcium leakageCalcium leakage––May leak from May leak from sarcoplasmicsarcoplasmicreticulumreticulum––Collects in mitochondria Collects in mitochondria ––Inhibits oxidative phosphorylationInhibits oxidative phosphorylationCalcium and enzymesCalcium and enzymes––Activate proteases that degrade cellular Activate proteases that degrade cellular proteins (contractile fibers)proteins (contractile fibers)Theories for DOMSTheories for DOMSInflammatory processInflammatory process––Breakdown of muscle proteinsBreakdown of muscle proteinsRelease prostaglandin and histamineRelease prostaglandin and histamineAccumulation of substancesAccumulation of substances––Stimulates pain receptorsStimulates pain receptorsTraining for Improved FlexibilityTraining for Improved FlexibilityStatic stretchingStatic stretching––Continuously holding a stretch positionContinuously holding a stretch position––Preferred techniquePreferred techniqueLess chance of injury or sorenessLess chance of injury or sorenessLess muscle spindle activityLess muscle spindle activity––Proprioceptive neuromuscular facilitation (PNF)Proprioceptive neuromuscular facilitation (PNF)Isometric contraction of muscle followed by Isometric contraction of muscle followed by stretchstretchDynamic stretchingDynamic stretching––Ballistic stretching movementsBallistic stretching