core strength and low back rehabilitation核心力量和腰背康复

1,Core stability and low back rehabilitation,Supportive texts and readingsStuart McGill, PhD - Professor University of Waterloo - Internationally recognized expert in spine function and injury prevention and rehabilitationLow Back Disorders 2007 (Human Kinetics)OutlineIntroductionAnatomy and Neutral PelvisAssessment ConditioningPrescription guidelines,2,Introduction,Low back and abdominal exercises are prescribed primarily for rehabilitation of injured low backPrevention of injuryAs a component of fitness training programsGoal is to stress both damaged and healthy supporting tissue to promote tissue repair while avoiding further excessive loading that can exacerbate existing structural weaknessACSM chapter discusses the science of understanding loading forces and revisits some common practices in abdominal and low back trainingMost effective train motor control system to activate spine stabilizersProgress to endurance trainingFinally enhance strength and flexibility,3,Core Stability,Stabilizing muscles - act to support muscle action by providing rigid base of support for movement Core stability provided by muscles in the torso connecting the spine, rib cage and pelvisWhen standing the pelvis and lumbar spine are oriented for maximal stability fig 1Goal of training is to maintain this “neutral spine” orientation throughout dynamic movementLumbosacral angle 41 degreesStabilizing exercise are ones that groove motor patterns and ensure a stable spine during activity,4,5,Anatomy of the Core,No one muscle is the most important muscle for stability - varies with movement patternFor athletes a conflict of stability and rhythmic contraction/relaxation of forced breathing existsAbdominal GroupIn addition to stabilization each muscle group contributes to trunk movementTransverse abdominusForced expulsion Internal obliquesLateral flexion, rotation to same side and flexion of trunkExternal obliquesLateral flexion of trunk to same side, rotation to opposite side and flexion of trunkRectus abdominusFlexion of trunk,6,7,Anatomy of the core,Back MusclesErector SpinaeTrunk extensionMultifidusLateral flexion, extension and hyperextension of the spineQuadratus lumborumHighly involved in lumbar spine stabilization - largely isometricLatissimus dorsiRole as spine stabilizer enhanced by pulling to chest in lat pull down exercise,8,9,Assessment,Muscular endurance closely related to spinal stability and risk of low back painBalance of muscular endurance among torso flexors, extensors and lateral musculature is most important in reducing injury riskAll tests evaluated on time to failure and compared to normative data for overall time and ratios between test scoresLateral musculature testTest performed on both sides of the bodyLying in full side bridge, legs extended, top foot in frontsubject supported on one elbow and feet while lifting hips off the floor to create a straight line over their body length Uninvolved arm placed across the chest with hand on opposite shoulderFailure occurs when person loses the straight-back posture and hip returns to ground,10,11,Assessment (cont),Flexor endurance testBegins with person in a sit-up posture with the back resting against a jig angled at 60 degreesKnees and hips flexed at 90 degreesArms folded across chestHands on opposite shouldersToes are secured by examiner or toe strapsTest begins by pulling support back ten centimetersFailure occurs when subject falls back and touches jig,12,13,Assessment (cont),Back extensors testUpper body cantilevered over the end of test bench - hands across chestTime to failure - drop from horizontalCPAFLA - similar test described in detail,14,Interpreting scores,Tests just described have reliability coefficients of .98 or greater Normative data is presented in Table 12.1 of Mcgill - Low back disorders (2002)Data gathered from healthy men (n=92) and women (n=137) with a mean age of 21Interpreting absolute endurance is secondary to interpreting the relationship among the three muscle groups (flexors, lateral, and extensors.)The following discrepancies in ratios of time to failure suggest unbalanced enduranceR / L side bridge > .05 away from unityFlexion / Extension > 1.0Either Side bridge / extension > .75,15,16,Training for core stability and low back health,Variable effectiveness has been found for training and rehabilitation programs for low back in different studiesVariability may be due to prescription of inappropriate exercises caused by a lack of understanding of tissue loading,17,Training for core stability and low back health,S McGill evaluated exercises with respect to tissue loading injury criteria, not solely for maximized muscle activityGeneral Role for exercise in low back healthStimulates hypertrophySlows (reverses?) degenerative conditionsEnhances nutritional benefits to spineMore effective than surgery, bed rest or flexibility training,18,Exercise Training,Focus on progressive exercise that emphasizes muscle contraction with the spine in neutral positionSpine posture determines interplay between ligament and muscle forcesExtensor muscles activated in neutral position reducing load on spineFully flexed spine fails at about 20-40% lower compressive load than with neutral position,19,Relative loads on the thirdlumbar disk for living subjects,Upright standing depicted as 100%,20,The line of gravity shifts further ventrally during relaxed unsupported sitting (B) as the pelvis is tilted backward and the lumbar lordosis flattens (this creates a longer lever arm).When sitting erect (C) the pelvic backward tilt is reduced and the lever arm shortens (still longer than when standing (A).,21,Exercise Training,Several exercises are required to train all of the muscles of the lumbar torsoIndividual fitness level, training goals, history of spinal injury should influence prescriptionExercises should avoid loading spine throughout ROM post injuryElite athletes may achieve higher performance levels by using full ROM in exercises,22,Abdominal Bracing and Neutral Spine,Teaching Abdominal bracingco-contraction of abdominal wall muscles for spinal stability1. Demonstrate joint stability in peripheral joint through flexor/extensor co-contraction have subject palpate demonstrator then themselves2. Identify core musculature - cough with hand above hips - palpate abdominal wall during contraction,23,24,Abdominal Bracing and Neutral Spine,Teaching Neutral spine1. lying on back, knees bent - place fingers between lumbar spine and floor hyper lordosis - increase gap from floorhypo lordosis - flatten back onto fingersCan utilize blood pressure cuff and observe rise and fall in pressure with same movements.2. Put subject through lifting exercise or simulated work situationsPlace long stick across lumbar, subject must maintain contact across lumbar, avoiding trunk flexion throughout motion.,25,26,Core Exercises,All endurance exercises should last up to seven to eight secondsProgression in program should come from adding more repetitions rather than adding durationUtilize normative data from assessments to develop client goals Curl ups reduce spinal compression compared to sit ups and leg raisesPress heel sit-ups - recent evidence advanced them as beneficial However, active hamstrings actually stimulate psoas activity and higher compressive penalty on spine,27,28,Abdominal Exercises,Partial Curl upsFocus on rectus abdominusDistinct upper and lower rectus abdominus do not exist in most people training can be accomplished with a single exerciseRetain neutral spine, do not flatten back to floorBeginnerSupine with hands supporting lumbar spineOne leg bent at 90 degreesLift thoracic and cervical spine as one unit, no cervical motion should occur (chin poking or chin tucking)Leave elbows on floor, contract rectus and lift head and shoulders off the floorIntermediate lift elbows slightly off floorAdvanced place fingers lightly on foreheadHead and neck must move as unit, maintaining rigid block position on thoracic spine,29,Abdominal Exercises,Horizontal Side bridgeChallenge lateral obliques and quadratus lumborumLow lumbar compressive loadVariable demand on rectus and others with progressive stages of exerciseRemedialStanding 45 degrees and leaning to wallLying on floor and raising legsUtilize back extension bench at 45 degrees and support from sideBeginnerLateral support on knees bent at 90 degrees and elbow, maintain torso straightTop arm across chest with hand on shoulderIntermediateLegs straight with top foot in frontVariation - incorporate longitudinal rolling of the torso forward and backwardAdvancedTransfer from one elbow to the other while maintaining abdominal bracing,30,Extensor exercises,Traditional extensor exercises - high spinal loads due to ext applied loads from weights of resistance machinesFig 13.9 bird dog RemedialRaise a hand or knee slightly off floorBeginnerSingle leg raise on hands and kneesIntermediateSimultaneous contra-lateral arm raise with leg raise - increases extensor challengeHold six to eight seconds when parallelAdvancedDo not rest by placing the and and knee on the floor after each holding repetitionSweep the floor with hand and return outCommon errors include hiking hips and not achieving neutral spineexercise lying prone and lifting legs is contraindicated for anyone at risk for low back injury due to hyperextension,31,32,Advanced exercises,athletes can incorporate forced breathing cycles into all exercisesLabile surfaces - exercise ball, wobble boardsIncrease co-contraction, doubling spinal load in many exercisesFig 14.1 and 14.2 (Mcgill - 2002)Not recommended until subject has achieved spinal stability and sufficiently restored load-bearing capacityCan delay improvements by causing exacerbating spine loads if adopted early in rehabilitative program,33,34,Advanced exercises,Ball Exercises Table top spineForward ball rollTotal body flexionCurl upPush up,35,36,37,38,39,40,Advanced exercises,Squat and Power cleansGreat for developing powerForm is more important than weight being lifted as injury is likelyEuropeans, practice technique for years before adding weightRecommend beginning from elevated position if not a competitive weight lifterMcGill recommends athletes use medicine ball in the same motion pattern to avoid high stress of lifting bar from ground,41,Aerobic exercises,Evidence supporting positive role of aerobic exercise in reducing incidence of low back injury and in the treatment of low back patientsWalkingLow levels of support tissue loadMild, prolonged activation of supporting musculatureStudy comparing elderly engaged in a variety of lifelong activitiesRunners - no detrimental changes in low back healthWeightlifters and soccer players - more disc degeneration and bulges,42,Flexibility,Flexibility of the spine has yet to be shown to improve outcomes of low back exercise programs or reduce risk of future injury in healthy populationsFlexibility of hip has shown to be important Avoiding end of ROM during athletic and daily activities can reduce risk for several types of injuriesLimit training to unloaded flexion/extensionFig 13.4 cat stretch - full ROM recommended only for athletes who have never had a back injuryHip and knee flexibility should be performed with neutral spineFig 13.5 and 13.6,43,44,Exercise Prescription,RecommendationsLow back exercise most beneficial if performed dailyNo pain, no gain does not applyInclusion of general exercise (aerobic) is most effectiveUnwise to perform full ROM of spine early in the morning - Disc more hydrated in morning Emphasis should be endurance over strength, for low back healthTraining objectives must be identified individually in terms of injury risk, optimizing health or maximizing athletic performanceMay take 3 months to observe inc function and pain reduction,