Core stability and low back rehabilitation

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Core stability and low back rehabilitation

• Supportive texts and readings
• Stuart McGill, PhD - Professor University of
  Waterloo - Internationally recognized expert in
  spine function and injury prevention and
  rehabilitation
• Low Back Disorders 2007 (Human Kinetics)
• Outline
• Introduction
• Anatomy and Neutral Pelvis
• Assessment
• Conditioning
• Prescription guidelines

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Introduction

• Low back and abdominal exercises are prescribed
  primarily for
• rehabilitation of injured low back
• Prevention of injury
• As a component of fitness training programs
• Goal is to stress both damaged and healthy
  supporting tissue to promote tissue repair
• while avoiding further excessive loading that can
  exacerbate existing structural weakness
• ACSM chapter discusses the science of
  understanding loading forces and revisits some
  common practices in abdominal and low back
  training
• Most effective
• train motor control system to activate spine
  stabilizers
• Progress to endurance training
• Finally enhance strength and flexibility

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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 pelvis
• When standing the pelvis and lumbar spine are
  oriented for maximal stability fig 1
• Goal of training is to maintain this neutral
  spine orientation throughout dynamic movement
• Lumbosacral angle 41 degrees
• Stabilizing exercise are ones that groove motor
  patterns and ensure a stable spine during
  activity

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Anatomy of the Core

• No one muscle is the most important muscle for
  stability - varies with movement pattern
• For athletes a conflict of stability and rhythmic
  contraction/relaxation of forced breathing exists
• Abdominal Group
• In addition to stabilization each muscle group
  contributes to trunk movement
• Transverse abdominus
• Forced expulsion
• Internal obliques
• Lateral flexion, rotation to same side and
  flexion of trunk
• External obliques
• Lateral flexion of trunk to same side, rotation
  to opposite side and flexion of trunk
• Rectus abdominus
• Flexion of trunk

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Anatomy of the core

• Back Muscles
• Erector Spinae
• Trunk extension
• Multifidus
• Lateral flexion, extension and hyperextension of
  the spine
• Quadratus lumborum
• Highly involved in lumbar spine stabilization -
  largely isometric
• Latissimus dorsi
• Role as spine stabilizer enhanced by pulling to
  chest in lat pull down exercise

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Assessment

• Muscular endurance closely related to spinal
  stability and risk of low back pain
• Balance of muscular endurance among torso
  flexors, extensors and lateral musculature is
  most important in reducing injury risk
• All tests evaluated on time to failure and
  compared to normative data for overall time and
  ratios between test scores
• Lateral musculature test
• Test performed on both sides of the body
• Lying in full side bridge, legs extended, top
  foot in front
• subject 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 shoulder
• Failure occurs when person loses the
  straight-back posture and hip returns to ground

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Assessment (cont)

• Flexor endurance test
• Begins with person in a sit-up posture with the
  back resting against a jig angled at 60 degrees
• Knees and hips flexed at 90 degrees
• Arms folded across chest
• Hands on opposite shoulders
• Toes are secured by examiner or toe straps
• Test begins by pulling support back ten
  centimeters
• Failure occurs when subject falls back and
  touches jig

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Assessment (cont)

• Back extensors test
• Upper body cantilevered over the end of test
  bench - hands across chest
• Time to failure - drop from horizontal
• CPAFLA - similar test described in detail

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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 (n92) and women
  (n137) with a mean age of 21
• Interpreting 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 endurance
• R / L side bridge gt .05 away from unity
• Flexion / Extension gt 1.0
• Either Side bridge / extension gt .75

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Training for core stability and low back health

• Variable effectiveness has been found for
  training and rehabilitation programs for low back
  in different studies
• Variability may be due to prescription of
  inappropriate exercises caused by a lack of
  understanding of tissue loading

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Training for core stability and low back health

• S McGill evaluated exercises with respect to
  tissue loading injury criteria, not solely for
  maximized muscle activity
• General Role for exercise in low back health
• Stimulates hypertrophy
• Slows (reverses?) degenerative conditions
• Enhances nutritional benefits to spine
• More effective than surgery, bed rest or
  flexibility training

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Exercise Training

• Focus on progressive exercise that emphasizes
  muscle contraction with the spine in neutral
  position
• Spine posture determines interplay between
  ligament and muscle forces
• Extensor muscles activated in neutral position
  reducing load on spine
• Fully flexed spine fails at about 20-40 lower
  compressive load than with neutral position

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Relative loads on the third lumbar disk for
living subjects
Upright standing depicted as 100
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• 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).

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Exercise Training

• Several exercises are required to train all of
  the muscles of the lumbar torso
• Individual fitness level, training goals, history
  of spinal injury should influence prescription
• Exercises should avoid loading spine throughout
  ROM post injury
• Elite athletes may achieve higher performance
  levels by using full ROM in exercises

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Abdominal Bracing and Neutral Spine

• Teaching Abdominal bracing
• co-contraction of abdominal wall muscles for
  spinal stability
• 1. Demonstrate joint stability in peripheral
  joint through flexor/extensor co-contraction
• have subject palpate demonstrator then themselves
• 2. Identify core musculature - cough with hand
  above hips - palpate abdominal wall during
  contraction

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Abdominal Bracing and Neutral Spine

• Teaching Neutral spine
• 1. lying on back, knees bent - place fingers
  between lumbar spine and floor
• hyper lordosis - increase gap from floor
• hypo lordosis - flatten back onto fingers
• Can utilize blood pressure cuff and observe rise
  and fall in pressure with same movements.
• 2. Put subject through lifting exercise or
  simulated work situations
• Place long stick across lumbar, subject must
  maintain contact across lumbar, avoiding trunk
  flexion throughout motion.

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Core Exercises

• All endurance exercises should last up to seven
  to eight seconds
• Progression in program should come from adding
  more repetitions rather than adding duration
• Utilize normative data from assessments to
  develop client goals
• Curl ups reduce spinal compression compared to
  sit ups and leg raises
• Press heel sit-ups - recent evidence advanced
  them as beneficial
• However, active hamstrings actually stimulate
  psoas activity and higher compressive penalty on
  spine

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Abdominal Exercises

• Partial Curl ups
• Focus on rectus abdominus
• Distinct upper and lower rectus abdominus do not
  exist in most people
• training can be accomplished with a single
  exercise
• Retain neutral spine, do not flatten back to
  floor
• Beginner
• Supine with hands supporting lumbar spine
• One leg bent at 90 degrees
• Lift 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 floor
• Intermediate
• lift elbows slightly off floor
• Advanced
• place fingers lightly on forehead
• Head and neck must move as unit, maintaining
  rigid block position on thoracic spine

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Abdominal Exercises

• Horizontal Side bridge
• Challenge lateral obliques and quadratus lumborum
• Low lumbar compressive load
• Variable demand on rectus and others with
  progressive stages of exercise
• Remedial
• Standing 45 degrees and leaning to wall
• Lying on floor and raising legs
• Utilize back extension bench at 45 degrees and
  support from side
• Beginner
• Lateral support on knees bent at 90 degrees and
  elbow, maintain torso straight
• Top arm across chest with hand on shoulder
• Intermediate
• Legs straight with top foot in front
• Variation - incorporate longitudinal rolling of
  the torso forward and backward
• Advanced
• Transfer from one elbow to the other while
  maintaining abdominal bracing

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Extensor exercises

• Traditional extensor exercises - high spinal
  loads due to ext applied loads from weights of
  resistance machines
• Fig 13.9 bird dog
• Remedial
• Raise a hand or knee slightly off floor
• Beginner
• Single leg raise on hands and knees
• Intermediate
• Simultaneous contra-lateral arm raise with leg
  raise - increases extensor challenge
• Hold six to eight seconds when parallel
• Advanced
• Do not rest by placing the and and knee on the
  floor after each holding repetition
• Sweep the floor with hand and return out
• Common errors include hiking hips and not
  achieving neutral spine
• exercise lying prone and lifting legs is
  contraindicated for anyone at risk for low back
  injury due to hyperextension

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Advanced exercises

• athletes can incorporate forced breathing cycles
  into all exercises
• Labile surfaces - exercise ball, wobble boards
• Increase co-contraction, doubling spinal load in
  many exercises
• Fig 14.1 and 14.2 (Mcgill - 2002)
• Not recommended until subject has achieved spinal
  stability and sufficiently restored load-bearing
  capacity
• Can delay improvements by causing exacerbating
  spine loads if adopted early in rehabilitative
  program

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Advanced exercises

• Ball Exercises
• Table top spine
• Forward ball roll
• Total body flexion
• Curl up
• Push up

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Advanced exercises

• Squat and Power cleans
• Great for developing power
• Form is more important than weight being lifted
  as injury is likely
• Europeans, practice technique for years before
  adding weight
• Recommend beginning from elevated position if not
  a competitive weight lifter
• McGill recommends athletes use medicine ball in
  the same motion pattern to avoid high stress of
  lifting bar from ground

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Aerobic exercises

• Evidence supporting positive role of aerobic
  exercise in reducing incidence of low back injury
  and in the treatment of low back patients
• Walking
• Low levels of support tissue load
• Mild, prolonged activation of supporting
  musculature
• Study comparing elderly engaged in a variety of
  lifelong activities
• Runners - no detrimental changes in low back
  health
• Weightlifters and soccer players - more disc
  degeneration and bulges

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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
  populations
• Flexibility of hip has shown to be important
• Avoiding end of ROM during athletic and daily
  activities can reduce risk for several types of
  injuries
• Limit training to unloaded flexion/extension
• Fig 13.4 cat stretch - full ROM recommended only
  for athletes who have never had a back injury
• Hip and knee flexibility should be performed with
  neutral spine
• Fig 13.5 and 13.6

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Exercise Prescription

• Recommendations
• Low back exercise most beneficial if performed
  daily
• No pain, no gain does not apply
• Inclusion of general exercise (aerobic) is most
  effective
• Unwise to perform full ROM of spine early in the
  morning - Disc more hydrated in morning
• Emphasis should be endurance over strength, for
  low back health
• Training objectives must be identified
  individually in terms of
• injury risk, optimizing health or maximizing
  athletic performance
• May take 3 months to observe inc function and
  pain reduction