Affiliations: [a] epartment of Rehabilitation Medicine, Skåne
University Hospital, Lund, Sweden | [b] Department of Clinical Sciences, Lund, Division of
Rehabilitation Medicine, Lund University, Lund, Sweden | [c] Department of Health Sciences, Division of Physical
Therapy, Lund University, Lund, Sweden
Note: [] Address for correspondence: Ulla-Britt Flansbjer, PhD,
Department of Rehabilitation Medicine, Lund University Hospital,
Orupssjukhuset, 221 85 Lund, Sweden. Tel.: +46 413 55 66 35; Fax: +46 413 55 67
09; E-mail: [email protected]
Abstract: The aim of this study was to assess the reproducibility of
isokinetic and isometric ankle dorsiflexor strength measurements in individuals
with post-polio syndrome (PPS). Thirty-one men and women (mean age 63 ±
7.0 years) with verified PPS, participated in an intra-rater test-retest
reproducibility study. Strength of the ankle dorsiflexor muscles in both lower
limbs were measured twice, seven days apart, with a Biodex dynamometer
(isokinetic concentric; 30°/s and isometric; ankle plantar flexion angle
10°). Reproducibility was evaluated with the intraclass correlation
coefficient (ICC_{2,1}), the mean difference between the
test sessions (�) and the 95% confidence intervals for �, the
standard error of measurement (SEM, 95% SEM and SEM%) and Bland & Altman
graphs. All 31 individuals completed the measurements in the less affected
lower limb, but only 14 in the more affected lower limb due to severe weakness
and/or joint stiffness. The analysis was therefore based on data from the two
lower limbs separately. The test-retest agreements were high,
(ICC_{2,1} 0.85 to 0.94) and measurement errors generally
small, and there was no discernible difference between the less and more
affected lower limbs. The mean isokinetic and isometric peak torque (Nm) for
the two lower limbs from the two test sessions ranged from 22.7 to 25.8. The
SEM, which represents the limit for the smallest change that indicates a real
change for a group of individuals, ranged from 2.51 to 3.74 Nm. In conclusion,
isokinetic and isometric muscle strength measurements of the ankle dorsiflexor
muscles in individuals with PPS are reproducible and can be used to detect
changes over time or after an intervention for groups of individuals.
Keywords: Postpoliomyelitis syndrome, muscle, skeletal, outcome assessment, rehabilitation, reproducibility of results, research design
