Nelson-Wong CSM 2010

8/14/2019 Nelson-Wong CSM 2010

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Changes in Muscle Activation Patterns and

Subjective Low Back Pain Ratings

During Standing in Response to an Exercise

Intervention

Erika Nelson-Wong and Jack Callaghan

Presented at the Combined Sections Meeting of the APTA - February 19, 2010


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Background and Rationale


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Purpose

Investigate the impact of a commonly used PT

exercise intervention on LBP development,clinical and biomechanical risk factors during

a prolonged standing task.


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Prolonged Testing Methods

2 Hour Prolonged Exposure

15 min

VAS VAS VAS VASVAS VASVASVAS VAS

Start of Session: End of Session:

Continuous EMG,Motion Analysis &

Kinetic Data Collection


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Participants 43 volunteers

22 male, 21 female

Age: 22.7 3.4 years BMI: 23.8 3.2 kg/m2

No history of low back

pain

Not employed in

occupation requiring

static standing


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Instrumentation

EMG 16 Channels 46 Motion

Tracking Markers

(8 segments)

Two In-Floor Force Platforms


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RR

ExerciseExercise

InterventionInterventionControl/usuControl/usu

al activityal activity

4 Weeks

QuestionnairesQuestionnaires

ClinicalClinical

AssessmentAssessmentClassification into PD/NPDClassification into PD/NPD

based on VAS scoresbased on VAS scoresDataData

Analysis ByAnalysis By

GroupGroup

Experimental Protocol

EMG PrepEMG Prep

MVCsMVCs

Beiring-Beiring-

SorensenSorensen

Endurance TestEndurance Test

StandingStanding

FlexionFlexion

MarkerMarkerset-upset-up

2-hour2-hour

StandingStandingFunctionalFunctional

MovementsMovementsFunctionalFunctional

MovementsMovements


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Successful at Inducing LBP During Standing

40% developed LBP (17/43)


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Predisposing Factors Identified on pre-Test

(+) Active Hip Abduction Test (Nelson-Wong et al., JOSPT, 2009)

Increased co-contraction of bilateral gluteus mediusmuscles

Shorter muscle rest times (Gaps) in gluteal muscles

Nelson-Wong and Callaghan, J Electromyography Kinesiol2009


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Response to Exercise Intervention

Large Effect SizeCohens d = -3.78

Nelson-Wong and Callaghan, J Electromyography Kinesiol, Accepted in revision, 2010

Decrease from 24.2 ( 4) to 8.93 ( 3.7) mm


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Response to Exercise Intervention Non-Significant Trend

(z=1.73,p = 0.08) for PD

exercisers to improve on theAHAbd Test

Large Effect SizeCohens d = 0.95

Nelson-Wong, et al.JOSPT, 2009


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Male PDEX had decreased

co-contraction of

bilateral gluteus medius

muscles

Large Effect SizeCohens d = 1.88

p < 0.001



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Increase in right gluteus

medius muscle rest timefor Male PDEX



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Conclusions

Large impact of exercise intervention on subjective pain reporting

Muscle co-activation profiles can be impacted through exerciseintervention (gender specific?)

Mechanisms for LBP during standing yet to be identified, may be

related to low level muscle fatigue


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Clinical Relevance

Identify individuals who are pre-disposed tostanding-related LBPBEFOREthey become patients

Targeted interventions aimed at specific predisposingfactors

More work needed to characterize mechanisms andinvestigate gender-specific responses


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Mary McMillan, PODS I,

PODS II Scholarships

Thank You!

Nelson-Wong CSM 2010

Documents

Transcript of Nelson-Wong CSM 2010