when biomechanics matters august 2015.key

8/17/2019 When Biomechanics Matters August 2015.Key

1/14

Reconceptualizing

Biomechanics within BPSwhen biomechanics matters

But

• It is unfair to completely neglect biomechanics

• This ignores the BIO of BPS

• We just need to put it in its place

• We need to be cautious in how we frame its

importance

When Biomechanics Matters (WBM)

• Acute injuries to protect damaged tissue

• High load activities• Interruption of habits associated with pain

• Temporary changes to desensitize the ecosystem

• Disconnect between task/sport demands and

current function

• Respect for adaptation (MSQ)

acute injuries -the need for protectionwhen biomechanics matters


2/14

Acute Injury Protection/Desensitizing

• Taping the arch or heel lift during acute Plantar

Fasciosis (6 weeks to desensitize)• Taping the knee for stair pain

• Others and thoughts?

…but

we still start with a BPS explanation even

with acute injuries or flare ups.

Reactive Tendinopathy

• re-enforce that the pain is protective andis not well correlated with damage

•gentle exercise/isometrics is still helpful

•we let it desensitize and then build back

up

heavy load activitieswhen biomechanics matters


3/14

High Load Activities

Heavy Squats, Deadlifts, Olympic Lifts

! tissue has a finite capacity of tolerating stress.

! form can influence the load on tissue

! Its here where we learn a lot from biomechanists

(e.g Stu McGill)

Injuries with Flexion and Compression

“Specimens had a lower yield point (43--63%) and ultimate compressive strength

(23--47%) when in a flexed posture than when in a neutral posture”

Gunning et al (2001)

“Dynamic testing was conducted to a maximum of 86400 bending cycles …

Herniation…occurred with relatively modest joint compression but with highly repetitive flexion/

extension moments. Increased magnitudes of axial compressive force resulted in more

frequent and more severe disc injuries.

The results support the notion that intervertebral disc herniation may be more linked to

repeated flexion extension motions than applied joint compression, at least with younger,

non-degenerated specimens”

Callaghan & McGill 2000

A practical message

while we have some research suggestingthe loads on the spine are comparable

to trying to maintain neutral there is no

research strongly saying that a flexed

spine under heavy conditions is safer

…but

Do not confuse the safely threshold gained inheavy loading with a need for that safety

threshold during simple tasks (sitting, standing,

picking up a feather)


4/14

The dreaded hip collapse

• Dynamic Knee

Valgus and PFPS/

ITBS

– correlational studies

– prospective studies

High Loads and Dynamic Valgus (Myer 2015)

• a KAM above 25.3 Nm was associated with a

6.8% risk for subsequent ACL injury comparedto a 0.4% risk if below the established ACL risk

threshold

• Maybe under heavy loading we look at changing

lower extremity mechanics.

• But can we explain this another way too?

under low loads thebiomechanical variable is not as

consistently related to pain

…perhaps…

Do not again confuse the safely threshold gained inheavy loading with a need for that safety

threshold during simple tasks (running, kneeling,

low load squats)


5/14

habit interruptionwhen biomechanics matters

Habit Interruption

Pain can become coupled with certain postures and

movements.

What one person can tolerate another with a

sensitized ecosystem can not.

Dankaerts et al 2006

“during sitting NSCLBP patients with a flexion pattern

disorder position themselves near the end of the

available flexion range at the symptomatic region of

the spine,whereas patients with an active extension

pattern disorder hold themselves actively into

hyperextension (potentially leading to abnormal

tissue strain and pain).”

Moving and Pain Memories

• Biomechanics matters here because certain

patterns of movement have become associated

with pain

• We need to change those patterns to interrupt that

habit

• In the past we would say this is more optimal

• Perhaps we are increasing comprehensive capacity

and movement repertoire


6/14

Changing habits need not be forever

• We change the habit for a reprieve

• This reinforces belief of modifiable sensitivity

• We don’t want to reinforce that they can never

perform that movement

• Only that they are currently sensitized to that

movement or posture

a thought…

are all structuraltreatments merely habit

changers?

Sahrmann

McGill

SFMA

CB-CFT

McKenzie

Running Re-education

if we have the capacity to adapt

perhaps all running re-education

interventions merely shift stress

for a period of time that allows

the body to desensitize


7/14

temporary changes

to desensitize theecosystem

when biomechanics matters

Temporary Changes to Desensitize the Ecosystem

• Changes in form

• Changes in habitual postures

• All used as temporary measures to minimize

irritation or to break a pain habit

• Not to be considered BAD form or correcting faulty

function

• Examples (squatting, running interventions, hip

hinge)

Sensitized Tendon: Avoid Compression

• Avoid calf stretching for achilles

– Increase running stride rate – Increased hip hinge squat

• Avoid hip dropping for Greater Trochanteric pain

Tape can Desensitize

• This is just a band aid

• Explain that it is purely neuromodulatory todesensitize in the short term

• Stress that nothing is being “corrected”


8/14

do we need to worry

about subtle changes inalignment or form?

reconciling the SICK Scapula

Greg Lehman MSc, DC, MScPT

Reconciling the SICK scap

• Can these cases be as simple as supraspinatus

tendinopathy• The tendon is sensitive and normal “pinching” with

elevation leads to pain

• SAT can be neuromodulatory as skin puckering

does the same Sx modulation

• What is a pragmatic approach that recognizes this

clinical doubt but is empowering?

Biomechanics in the BPS Framework

• Reiterate that pain is more about sensitivity than

damage

• When it is about damage then focus on the bodies

ability to adapt to load rather than a multitude of

impairments

Treating the “SICK” scap

• Load the irritated tendon

• Find neuromodulatory movements to break the painhabit/couple with arm elevation

• Assess for other protective behaviours (trunk and

neck stiffness) and encourage novel movements

• Encourage painfree loading of both the scapula

and GH muscles

• Train in all planes and progress to comprehensive

capacity


9/14

What do we say?

• The tendon is sensitive

• It hasn’t been given a reason to adapt so it staysprotective and defensive

• Other body regions do the same

• We anticipate pain with movement so we have to

get comfortable raising the arm again

• Modifications are short term bandaids to desenstive

The positive message continued

• None of these explanations blame the patient, their

anatomy or impairments• Shifts to defensive protection mode

• We convince the body protection is not necessary

• We avoid correcting posture because this does not

have to change and if we sell that they can worry

about this “defect”.

Do we care about structural source ofnociception?

• No. We don’t even have to know if an impairment

is the cause or consequence

• Use symptom modifiying techniques to change

sensitivity and perhaps we “corrected” form but its

not relevant

• Use comprehensive capacity to cover all our bases

matching sport demandsto individual functionwhen biomechanics matters


10/14

WBM: Matching sport demands to

individual function

• Strength is protective (Laursen 2015)

– Strength needs are task specific – Hockey

• Mobility is needed in certain sports

– Gymnastics

– Golf

• Blanket statements are difficult

– Individuals are also able to adapt and tolerate load

Simple strength is important

Groin injury and strength is linked (Ryan 2014)

• OR= 4.28 (1.31-14) for weak hip adductors

Hamstring Eccentrics in Soccer Players (Petersen 2011)

• Comparing intervention versus the control group, overall

acute hamstring injury rates per 100 player seasons

were 3.8 versus 13.1 (adjusted rate ratio [RR], 0.293;

95% confidence interval [CI], 0.150-0.572; P < .001).

Hamstring Loading

Hamstring Strain Prevention


11/14

Nordic Hamstring Curl

Arnason (2007)

The main finding of the present study was that eccentric strength

training with Nordic hamstring lowers combined with warm-up

stretching seems to be effective in preventing hamstring strains in

soccer.

In contrast, stretching during warm-up and flexibility training of the

hamstrings group had no effect on the incidence of hamstring strains

Big Study (n=942)

!10 week intervention performed on MidSeason Break

!27 sessions of Nordic Hamstrings over 10 weeks


12/14

Nordic Hamstring Results

!67 acute hamstring injuries

!44 new and 23 recurrent

!15 injuries in intervention group (12 new and 3 recurrent)

!52 injuries in the control group (32 new and 20 recurrent)

!no injuries during the exercise

!Number needed to treat (NNT) = 13 to prevent 1 injury

!NNT for a new injury = 25

!NNT for a recurrent injury = 3

Petersen (2011)

screening

implications?all physical assessment screenings should be both

simpler (test biomotor abilities) and more complex (testthe exact demands of the sport)


13/14

Not a panacea

• Strength and mobility training may be most useful

when loading approaches tolerance• Does not make sense in activities when loading is

not near tolerance

• Although we can promote general strength and

fitness training for other reasons to modulate pain

respect for adaptationwhen biomechanics matters

Respect for Adaptation (MSQ)

• Too much too soon happens frequently and many

athletes get away with it but many don’t

• Evaluate the training program of your painful

patients

• Do people persist in poking the bear when they

have exceeded their threshold to adapt

• What factors in their life might influence their

threshold to adapt

Load matters…sometimes

• Nyman 2009

– In the cohort analysis, the association between high physical workload and the group with

any one symptom (LBP and/or NSP) was OR 1.47 (95% CI 1.37 to 1.57). The co-twincontrol analyses indicated that the association was not confounded by genetic and shared

environmental factors with OR 1.34 (95% CI 1.02 to 1.75) for dizygotic twins and OR 1.44

(95% CI 1.06 to 1.95) for monozygotic twins

• Hartvigsen 2003

– Statistically significant graded relations were found for increasing workload and

LBP of longer duration but not for LBP of shorter duration (


14/14

Many factors influence adaptability

Consider the ecosystem

when biomechanicsmatters?they are part of the ecosystem and are influenced by a

myriad of factors.

We will never parse their exact importance and will continueto be deceived into believing they are extremely important

or not important at all based on the limits of our ownpersonal interactions

when biomechanics matters august 2015.key

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