Concurrent validity between clinical timed static and dynamic balance and laboratory stabilometry me

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Concurrent validity between clinical timed static
and dynamic balance and laboratory stabilometry
measurements

• Jess Schaink

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Introduction

• Significance
• Proprioceptive balance training is a key element
  in sports medicine for both injury prevention and
  rehabilitation
• Developing a clinical tool to measure standing
  balance is essential so that such training can be
  evaluated

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Introduction Definitions

• Proprioception
• the afferent input of joint position sense which
  gives an individual awareness of joint position
  or movement and incorporates neuromuscular and
  postural control including balance (Laskowski et
  al, 1997)
• Balance
• the bodys ability to maintain its centre of
  gravity over its base of support with maximal
  steadiness (Horak, 1987 Shumway-Cook et al.,
  1988)

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Introduction Background

• No gold standard
• Laboratory techniques are impractical
• Concurrent validity between eyes closed static
  (ECS) and eyes closed dynamic (ECD) timed
  unipedal balance and stabilometry measures is
  largely unknown

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Introduction Background

• Emery et al., 2003
• Timed unipedal ECS and ECD balance measurement
  are reliable and appropriate measures for use in
  healthy adolescents
• Ekdahl 1989, Riemann 1999
• Limited evidence of concurrent validity between
  timed unipedal static balance measurements and
  laboratory stabilometry readings (r0.31-0.42)

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Introduction Factors which may influence balance

• Age
• Gender
• Leg dominance
• Height
• Weight
• Foot size
• Foot wear
• Fatigue

• Previous injury
• Sport participation level
• Sport participation specificity
• Visual feedback
• Learning effects

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Methods

• Participants
• 20 University students
• (10 male, 10 female)
• Equipment
• Airex balance pad, PEDAR flexible insole system,
  knee high nylons, Timex stopwatch, balance scale,
  anthropometer, 1cm2 graph paper

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Methods

• Procedure
• Baseline questionnaire and consent forms
• Height, weight, foot tracing
• Time to familiarize with the Airex balance pad
• Pedar insoles affixed to feet using nylons

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Methods
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Methods

• Timed until loss of balance
• Eyes open, hands off hips, weight-bearing foot
  shuffle, non-weight-bearing foot touch down
• Minimum trial length 2 second
• Maximum trial length 180 seconds
• Trials collected
• 3 static, 6 dynamic

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Methods

• Variables examined
• Medial-lateral center of pressure (ML) excursion
• Anterior-posterior center of pressure (AP)
  excursion
• Total center of pressure excursion
• Using area plot of center of pressure excursion
  created in MS Excel and analyzed for area using
  Microstation

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Analysis

• Descriptive statistics
• Logarithmic transformation of the data
• Geometric means, measure of central tendency
• T-test, paired t-tests, and ANOVA
• Influence of leg dominance, gender, age,
  potential learning and fatigue
• Linear regression
• relationships between timed ECS and ECD balance
  with AP, ML and total COP excursion as well as to
  investigate the influence of several other
  factors

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Results
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Results

• Data was logarithmically transformed as they
  deviated significantly from normal curve
• No evidence of difference between right and left
  leg
• Geometric mean, the measure of central tendency
  used, was obtained by back transformation of log
  transformed mean

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Results

• No evidence of learning effect over 3 static or 6
  dynamic trials
• No significant associations between log
  transformed ECS or ECD balance and any base line
  measurements
• Age (years), gender, leg dominance, previous
  injury (lower extremity), previous injury (all),
  height weight, BMI, foot length, foot width,
  sport participation previous 6 weeks, sport
  participation in the past year

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Results

• H
• hi
• E
• ECS versus ECD timed balance

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Results

• Due to malfunctioning of the PEDAR system, only
  the data for the first three subjects could be
  interpreted
• Only graphical trends will be described

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Results


ECD AP vs ML ECD total COP vs ML
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Results

ECD total COP vs AP
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Results

Timed ECS balance vs AP Timed ECS balance vs ML
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Results

Timed ECS balance vs total COP
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Results

Timed ECD vs AP Timed ECD vs ML
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Results

Timed ECD vs total COP excursion
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Discussion

• No significant association between balance and
• Gender
• Age
• Leg dominance
• Foot length, foot width, height, weight, BMI
• Sport involvement in 6 weeks prior to testing
• Previous injury

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Discussion

• No evidence of learning or fatigue effect
• Consistent with Nawoczenzi et al., 1991
• Inconsistent with Balogun et al. 1992 Emery et
  al. 2003 Ekdahl et al., 1985 Noweczenzi et al.,
  1991, who demonstrated a learning effect over the
  first three trials
• Geometric means ECS 19.2 seconds (95 CI
  10.99-33.54) and ECD 6.11 seconds (95 CI
  4.87-7.18)
• Consistent with Emery et al., 2003 with geometric
  means of 25.4 seconds (95 CI 17.5-33.38) and
  5.3 seconds (95 CI 3.83-5.91) respectively

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Discussion

• Positive association between static and dynamic
  balance
• Suggests overall effectiveness of proprioceptive
  system
• Positive association between AP, ML, and total
  COP excursion
• Intuitive as total excursion is dependent upon AP
  and ML

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Discussion

• Negative association between ECS and AP, ML and
  COP excursion
• Suggests less excursion is related to greater
  stability and therefore longer timed balance
  measurements
• Positive association between ECD and AP, ML, and
  COP excursion
• Suggests that individuals who can allow their COP
  to shift significantly can adapt to the dynamic
  surface and thus maintain their balance longer

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Discussion

• Limitations
• PEDAR malfunctions leading to a sample size of 3
• Future research
• Analyzing the remaining data thus creating a
  larger sample size and permitting the use of
  parametric analysis

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Conclusion

• Based on the trends demonstrated by these three
  subjects
• On a static surface
• Greater stability is reflected by less sway and
  is demonstrated by longer balance trials
• On a dynamic surface
• Greater COP excursion reflects an ability to
  adjust to the dynamic nature of the surface and
  maintain balance for a longer period of time

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Acknowledgements

• Dr. Carolyn Emery
• Dr. Reed Ferber
• Dr. Benno Nigg
• Human Performance Laboratory
• Markin-Flanagin Studentship Program
• Sport Medicine Center

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Questions?