Transcript Core strength and low back rehabilitation

Core stability and low back
rehabilitation
• Supportive texts and readings
– CSEP Position Stand : The use of instability to train the core in
athletic and nonathletic conditioning – Applied Physiology
Nutrition Metabolism Volume 35 p 109-112, 2010
– Stuart McGill, PhD - Professor University of Waterloo Internationally recognized expert in spine function and injury
prevention and rehabilitation
• Low Back Disorders 2007 (Human Kinetics)
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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
– CSEP-PATH - 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 (n=92) and women (n=137) 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 > .05 away from unity
• Flexion / Extension > 1.0
• Either Side bridge / extension > .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
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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 avoid contact across
lumbar by 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 position28on
thoracic spine
Abdominal Exercises
• Horizontal Side bridge
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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
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Table top spine
Forward ball roll
Total body flexion
Curl up
Push up
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Advanced exercises –
ground based free weights
• Olympic lifts, Squats and Power cleans
– Great for developing strength and power in athletes
– Regular core training on unstable surfaces not ideal
when trying to maximize power, hypertrophy and
absolute strength in athletes or general population
– Both Olympic lifts and instability training are important
components an athletes periodized program
• 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 - athletes should use medicine ball with Olympic
lifts 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
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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
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