Peter Konrad - EMG in Gait Analysis

Nor ora axo xon n EMG EMG Wor Works ksho hop p 201 2011

EMG Pro rocessi cessing ng & Analys A nalysis is Tech chni niqu que es fo forr Gait Gait Peter Konrad – PhD Sports Sports Science Lead Lead Software & App lication Design Design er Noraxon Noraxo n USA, Inc.

Hosted by: Dr. Chris Powers Movement Movement Performance Institu te Los An geles, Califo Califo rnia

Noraxon Nora xon User Meeting Meeting 2011

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Topics

1.

New Ha Hardwa rdware re Aspe Aspect cts s

2.

Elect lectro rode de Recomm comme enda nd ation tions s

3.

A r t i f ac t Man ag em en t

4.

Signa ignall Pro Proce cess ssin ing g Routi outine nes s

5.

Time ime Norma or mali liz zed Ave Averagi raging ng On/O n/Off P























1- Hardwa rdware re























EMG Mil ile esto stone ne Teleme lemetr try y

1980

1990

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Clea leaner ner Signals

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Less Less noise noise inte interfere rference nce

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Easier sier handlin handling g























Bene Be nefits fits of Late Latest st EMG Te Technology

2008

Direct irect Transmission ransmission Syste Systems ms

Key Benefit Benefits: s: 

Very Very fast fast/e /eas asy y hand handli ling ng

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No cabl cable e fixa fixatio tion n

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Natu Natura rall move movemen mentt

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Very helpful for smal mall sub subjects























Bene Be nefits fits of Late Latest st EMG Te Technology ...even ven non specia specialis lists ts can can easily sily use EMG

























Exce xcelle llent nt Arti Artifa fact ct Sta tability bility Stabl table e base baseli line ne even ven unde un derr hea heavy impa im pact ct cond co ndit itio ions ns























Long Lon g Dis Distance tance Transmis ransmissio sion n Natural tural and unlimited unlimited moveme movement nt

Subject on 100 100 Meter Meter













































Ele lectro ctrode de Recommenda commendation tion Recommenda commendations tions given given by interna internationa tionall rese resea arch societie societies s

Typical:























Fre ree e Sele lection ction of Ele Electrode ctrode Type Elect lectro rode de sele select ctio ion n rela relate tes s to the th e inte in tend nde ed use us e 1

4

  2

3

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Single / Dual electrodes Adhesive or Wet Gel Re-usable Re-usable (Beckmann (Beckmann style)

























Top Mounted Mounted Tra ransmi nsmissio ssion n Probes

























Fle lexibl xible e Use via Mini Mini Cable

























Fine Wire Ele lectrode ctrodes s

























Ap A p p l i c at atii o n Ex Exam amp p l e Fi Fin n e Wir Wi r e

























Us e of Fine Wi Wi re



















































































































































































































































































































Norma ormaliz liza ation Data from Perry Inappropriate MVC tests cre cr eate unre un rea alist listic ic data data in gait gait tria tr ials ls

Data Data for for norm normal al walk walkin ing galread already y at 80% 80% MVC? MVC?























Supr upra a- Maxim xima al EM EMG

Inappropria nappropriate te MVC tests tests crea create suprasupramaximal maximal EMG data























Supr upra a- Maxim xima al EM EMG

Possible Causes: uses: 

Sub Subject jects s are are not not fami famila larr with with MVC MVC con contrac tracti tion on

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Inappr Inappropr opriat iate e arrang arrangeme ement nt of MVC MVC exerc exercise ise

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Stat tatic vs Dynam ynamic ic cond condit itio ion n

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Bett Better er sync synchr hron oniz izat atio ion n of moto motorr unit units s in dyna dynami mic c cond condit itio ions ns => more more elec electr tric ical al sign signal al supe superp rpos osit itio ion n























MVC-Test-Positions























MVC-Test-Recommendations

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Subj Subjec ects ts need need some some MVC MVC trai traini ning ng

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Full Full bod body sup support port

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Always ask for full body tension

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Prov Provid ide e exte extern rnal al motiva motivati tion on

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Use Use heav heavy y exer exerci cise se mach machin ines es with with soli solid d cons constr truc ucti tion ons, s, fixa fixati tion on belt belts, s, musc muscle le isol isolat atio ion n (sin (singl gle e join jointt test tests) s)

























ISE IS EK Re Reco comm mme end ndatio ation n MVC

Wit Without hout trai traini nin ng, the MVC MVC co could uld be as muc much h as 20-3 20-30 0 % les less s than than that that























To Mean Mean Nor Normali maliz zati tion on Norma ormaliz lization tion to the inte in terna rnall mea mean show sh ows s lowe lo west st vari varia abili bi lity ty in group group curve cu rves: s:























Impact on Analysis Analysi s Some om etime ti mes s the th e MVC can can add more mo re error rr or than than bene benefi fitt Al A l t ern er n ati at i v es: es : 

Curv Curve e shap shape e of (ave (avera rage ged) d) EMG EMG is not not alte altere red d by norm normal aliz izat atio ion n













































Stride Varia riability bility

























Av A v er erag agii n g o f Mo Mott i o n Cy Cyc c l es

























Tim ime e Nor Normaliza malizati tion on

























Av A v er erag aged ed EMG Cur Cu r v es

























EMG Norm Norma ati tive ve Da Data by Wint inte er

























EMG Norm Norma ati tive ve Da Data by Ebe berhart rhart



















































































































































































































































































































3D - Accele Acceleromete rometer r

Heel strikes























Foo oott Swi witc tch h B ase sed d Gait An Ana aly lysi sis s Foot oot Switch witch o r So l e

Multi-mode or multimulti-sta stair ir signal: each sensor sensor switche switches s with with























Inte ntegra grate ted d Insol nsole e Pre ressur ssure e Distrib istributio ution n Telemetric Insole System Medilogic:

3D Visualization of Foot Pressure:























Full Cont Conta act Are Area a de dete tectio ction n EMG EMG or bi omech. sensor recording up to 16 16 ch.

Synchroni zed zed DV Video up t o 50 HZ HZ























Gait Eve vents nts via Kine Kinema matic tic Calcula lculation tion

Left Left ankle ankle velocity

Left Left vertic vertical al force Virtua Virtuall Foot Foot switch switch event event Right ankle velocity

Right vertical force

























Optic ptica al Foot Switch witch//Conta ontact ct Syste ystem m

Technical chn ical Specifi Specifications cations:: 

LED Light Light beams, beams, appr. appr. 0.5 cm above above ground ground



Distan Distance ce betwee between n beams: beams: 1 cm























Con onta tact ct Fre ree e Virt irtua uall Foo oott Swit witch ch Can Can be used on treadmill and for f loor loo r walking























Long Pressure Pressure Pla late tes s Technical chn ical Specif Specification ications: s: 

1 cal calib ibra rate ted d sens sensor or per per squ squar are e cm



Up to to 9 met meter er long long























Pre ressure ssure Pla late te Instrume nstrumente nted d Tre rea admill

Foot print detection with 3D presentation presentation of data

Synchronized DV Video up t o 50 HZ HZ























3D Forc orce e Plate Trea readmi dmill ll 3D Instrumented Instr umented Dual Belt Treadmi Treadmi ll Bertec

EMG

























Gait Ana Analysis lysis Re Report

















































Key Ke y Strate Strategy gy For Inte nterpreta rpretation tion -1

























Key Ke y Strate Strategy gy For Inte nterpreta rpretation tion -2

























Operational Background



















































































































































































































































































































Sug uggested gested Term rmin inol ology ogy for EMG Patt tte ern rns s by Perry

Ad A d d r ess es s i n g amp am p l i t u d e i n t ens en s i t y

Excessive t l o v o r c i M

Time normalized cycle [%]

In ad eq u at e

A b s en t























Cli lini nical cal EM EMG Fin indi ding ngs s

Continuous ontinuous Activity Activity Tib.Ant. ib.Ant.

Prema remature ture activity ctivity of soleus soleus at stance stance phase phase Inade nadequa quate te activa ctivation leve levell of Tib.Post. Tib.Post. in terminal terminal stance

Prolonge rolonged d activity ctivity of Tib.Ant ib.Ant.. at Swing Premature, inadequate























Hemi mipl ple egi gic c EMG EMG Fin Findi ding ngs s Giuliani

Typica ypic al observations/ observations/e expectations: xpectations:

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Lowe Lowerr EMG EMG on on the the paret aretic ic limb limb



Prol Prolon onge ged d musc muscle le burs burstt dura durati tion on

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Toni Tonic c rath rather er tha than phas phasic ic acti activi vity ty at gait ait tran transi siti tio ons

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Peri Period ods s of peak peak musc muscle le activ ctivit ity y that hat do not coin coinci cid de with ith requ requir irem eme ents nts























Literatur Li terature e Da Data Davis























From EMG Findings Findings to Tre Trea atme tment nt Therapeutic herapeutic conseque con sequences nces b ased on EMG investigation : 

Iden Identi tifi fica catio tion n of key key muscl muscles es (“Gui (“Guilt lty y Muscle Muscles” s”(1))

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Uptrai Uptrainin ning g of atrop atrophic hic,, weak, weak, inhibit inhibited ed muscles muscles

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Downtr Downtrain aining ing of overus overused, ed, hyper hyperact active ive muscles muscles

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Stabil Stabilizat ization ion Traini Training ng of of segmen segmental tal and joint joint stabili stabilizer zer muscles muscles



Traini Training ng of body body awaren awareness ess



Re-e Re-edu duca cati tion on of faul faulty ty moti motion on patt patter erns ns/p /pro rogr grams ams

























Cit ite ed Books Boo ks























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Peter Konrad - EMG in Gait Analysis

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