Vicki Whittaker

Publications (2)0 Total impact

• Article: Effect of shoe heel height on vastus medialis and vastus lateralis electromyographic activity during sit to stand

  Lindsay Edwards, John Dixon, Jillian Kent, David Hodgson, Vicki Whittaker
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  ABSTRACT: Abstract Background It has been proposed that high-heeled shoes may contribute to the development and progression of knee pain. However, surprisingly little research has been carried out on how shoe heel height affects muscle activity around the knee joint. The purpose of this study was to investigate the effect of differing heel height on the electromyographic (EMG) activity in vastus medialis (VM) and vastus lateralis (VL) during a sit to stand activity. This was an exploratory study to inform future research. Methods A repeated measures design was used. Twenty five healthy females carried out a standardised sit to stand activity under 4 conditions; barefoot, and with heel wedges of 1, 3, and 5 cm in height. EMG activity was recorded from VM and VL during the activity. Data were analysed using 1 × 4 repeated measures ANOVA. Results Average rectified EMG activity differed with heel height in both VM (F_{2.2, 51.7}= 5.24, p < 0.01), and VL (F_{3, 72}= 5.32, p < 0.01). However the VM: VL EMG ratio was not significantly different between conditions (F_{3, 72}= 0.61, p = 0.609). Conclusion We found that as heel height increased, there was an increase in EMG activity in both VM and VL, but no change in the relative EMG intensity of VM and VL as measured by the VM: VL ratio. This showed that no VM: VL imbalance was elicited. This study provides information that will inform future research on how heel height affects muscle activity around the knee joint.
  Journal of Orthopaedic Surgery and Research. 01/2008;
• Article: An exploration of the use of simple statistics to measure consensus and stability in Delphi studies

  Elizabeth Holey, Jennifer Feeley, John Dixon, Vicki Whittaker
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  ABSTRACT: Abstract Background The criteria for stopping Delphi studies are often subjective. This study aimed to examine whether consensus and stability in the Delphi process can be ascertained by descriptive evaluation of trends in participants' views. Methods A three round email-based Delphi required participants (n = 12) to verify their level of agreement with 8 statements, write comments on each if they considered it necessary and rank the statements for importance. Each statement was analysed quantitatively by the percentage of agreement ratings, importance rankings and the amount of comments made for each statement, and qualitatively using thematic analysis. Importance rankings between rounds were compared by calculating Kappa values to observe trends in how the process impacts on subject's views. Results Evolution of consensus was shown by increase in agreement percentages, convergence of range with standard deviations of importance ratings, and a decrease in the number of comments made. Stability was demonstrated by a trend of increasing Kappa values. Conclusion Following the original use of Delphi in social sciences, Delphi is suggested to be an effective way to gain and measure group consensus in healthcare. However, the proposed analytical process should be followed to ensure maximum validity of results in Delphi methodology for improved evidence of consensual decision-making.
  BMC Medical Research Methodology. 01/2007;