Anna Maria Holmbäck, Michelle M. Porter, David Downham, Jan Lexell
^A1 Department of Physical Therapy, Lund University, Sweden
^A2 Faculty of Physical Education and Recreation Studies, University of Manitoba, Canada
^A3 Department of Mathematical Sciences, University of Liverpool, UK
^A4 Department of Rehabilitation, Lund University Hospital, Sweden

DOI: 10.1080/165019701750098966

The aims of this study were: (i) to assess the test-retest intrarater reliability of eccentric ankle dorsiflexor muscle performance in young healthy men and women using the Biodex dynamometer; and (ii) to examine different statistical indices for the interpretation of reliability. Thirty men and women (age 22. 5 - 2. 5 years, mean - S. D. ) performed three maximal eccentric contractions at 30 °/second and 90 °/second, with 7-10 days between test sessions. Reliability was evaluated with three intraclass correlation coefficients (ICC 1,1 , ICC 2,1 and ICC 3,1 ), and was excellent for peak torque (ICC 0. 90-0. 96) and good to excellent for work (ICC 0. 69-0. 83), with no discernible differences among the three ICCs. Method errors, assessed by the standard error of the measurement (S. E. M. ) and S. E. M. %, were low. The Bland & Altman graphs and analyses indicated no significant systematic bias in the data. In conclusion, measurements of eccentric ankle dorsiflexor muscle performance in young healthy individuals using the Biodex are highly reliable.