When Biomechanics Matters August 2015.Key

But

Reconceptualizing 
 Biomechanics within BPS when biomechanics matters

• 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 protection when biomechanics matters

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 and is not well correlated with damage • gentle exercise/isometrics is still helpful • we let it desensitize and then build back up

heavy load activities when biomechanics matters

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 suggesting the 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 in heavy loading with a need for that safety threshold during simple tasks (sitting, standing, picking up a feather)

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 compared to 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?

…perhaps… under low loads the biomechanical variable is not as consistently related to pain

Do not again confuse the safely threshold gained in heavy loading with a need for that safety threshold during simple tasks (running, kneeling, low load squats)

Habit Interruption

habit interruption when biomechanics matters

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).”

Pain can become coupled with certain postures and movements. What one person can tolerate another with a sensitized ecosystem can not.

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

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

a thought…

• Only that they are currently sensitized to that movement or posture

McKenzie

McGill

Running Re-education

SFMA

are all structural treatments merely habit changers? CB-CFT Sahrmann

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

Temporary Changes to Desensitize the Ecosystem

temporary changes to desensitize the ecosystem when biomechanics matters

• 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

Tape can Desensitize • This is just a band aid • Explain that it is purely neuromodulatory to desensitize in the short term • Stress that nothing is being “corrected”

• Avoid hip dropping for Greater Trochanteric pain

Reconciling the SICK scap

do we need to worry about subtle changes in alignment or form? reconciling the SICK Scapula

• 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? Greg Lehman MSc, DC, MScPT

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 pain habit/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

What do we say? • The tendon is sensitive • It hasn’t been given a reason to adapt so it stays protective and defensive

The positive message continued • None of these explanations blame the patient, their anatomy or impairments • Shifts to defensive protection mode

• Other body regions do the same

• We convince the body protection is not necessary

• We anticipate pain with movement so we have to get comfortable raising the arm again

• We avoid correcting posture because this does not have to change and if we sell that they can worry about this “defect”.

• Modifications are short term bandaids to desenstive

Do we care about structural source of nociception? • 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 demands to individual function when biomechanics matters

WBM: Matching sport demands to individual function • Strength is protective (Laursen 2015) – Strength needs are task specific

Simple strength is important Groin injury and strength is linked

(Ryan 2014)

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

– Hockey • Mobility is needed in certain sports – Gymnastics – Golf • Blanket statements are difficult – Individuals are also able to adapt and tolerate load

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 Strain Prevention

Hamstring Loading

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

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 (test the exact demands of the sport)

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

respect for adaptation when biomechanics matters

• Although we can promote general strength and fitness training for other reasons to modulate pain

Respect for Adaptation (MSQ) • Too much too soon happens frequently and many athletes get away with it but many don’t

Load matters…sometimes • Nyman 2009 –

• 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

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-twin control 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 (