Rare Diseases Symptoms Automatic Extraction

Lower extremity peak force and gait kinematics in individuals with inclusion body myositis.

[inclusion body myositis]

Objective: To determine the relationship between peak isometric muscle force and temporal characteristics of gait in individuals with sporadic inclusion body myositis (s-IBM). Patients and Methods: An observational study of 42 individuals with s-IBM (12 female; age: 61.6 ±7.3 years [mean ±standard deviation]; disease duration 8.9 ±4.3 years) was conducted at a Federal hospital. Peak isometric force measurements for lower extremity (LE) muscle groups were obtained using quantitative muscle testing. Temporal characteristics of gait during habitual and fast walking conditions were measured using a portable gait analysis system. Results: All observed muscle force values were significantly lower than predicted values (p <.001). During habitual walking, subjects' gait speed and cadence were ≤ 83% of normative literature values. During the fast walking, total gait cycle time was 133% of normal, while gait speed and cadence were 58% and 78%, respectively, of normative literature values. Scaled LE peak muscle forces showed significant moderate correlations with the temporal gait variables. Weaker subjects demonstrated greater limitations in gait speed and cadence compared to stronger subjects (p <.05). Peak isometric force of the knee flexors and ankle plantar flexors, but not knee extensors, were significantly correlated with most temporal features of habitual gait. Conclusions: Muscle weakness associated with s-IBM disease activity may contribute to diminished gait kinematics. Temporal features of gait are not substantially influenced by knee extensor weakness alone, as the knee flexors and ankle plantar flexors play a compensatory role in maintaining the walking ability of individuals with s-IBM. © 2014 American College of Rheumatology.