Affiliations: [a] School of Physiotherapy, La Trobe University,
Bundoora, Vic.3083, Australia | [b] School of Psychological Sciences, Faculty of Science
and Technology, and Convenor, Movement Rehabilitation Research Group, La Trobe
University, Bundoora, Vic. 3083, Australia
Note: [] Corresponding author
Abstract: This research investigated factors influencing unpredictable
variability in dynamometric measurements. The criterion for inclusion in this
review was that the standard error of measurement (SEM) associated with test
procedures could be estimated. SEMs were determined using reported retest
correlations and standard deviations of measurements. Subject factors found to
influence variability were impairment and gender. Test factors implicated were
movement direction and test speed. A strong relationship was indicated between
score magnitude and variability. SEMs derived from measurements of low scoring
subjects do not appear appropriate for interpreting measurements of higher
scoring subjects. Measurements of subjects who achieve higher dynamometry
scores appear more variable than measurements of lower scoring subjects.
Similarly, as test conditions facilitate higher scores eg lower test speeds,
variability in measurements increases. SEMs employed by clinicians to interpret
test results should be derived from a population with a mean measurement that
is representative of the subject being tested.
Keywords: dynamometry scores, measurement variability, SEM, subject factors, test conditions
