Relation between spasticity, weakness and contracture of the elbow flexors and upper limb activity after stroke: An observational study

Purpose. Understanding the relationship between the motor impairments and their impact on physical activity will allow rehabilitation after stroke to be based on scientific principles. The aims of this study were to determine: ( i) the relative contribution of weakness and spasticity to contracture, and ( ii) the relative contribution of all three impairments to limitations in physical activity during the first 12 months after stroke. Method. This longitudinal observational study charted the evolution of weakness ( loss of maximal force), spasticity ( stretch-evoked EMG) and contracture ( loss of joint range) of the elbow flexors and limitations in upper limb activity ( Motor Assessment Scale) for a year after stroke in 27 subjects who had suffered a first stroke. Spasticity was measured as abnormal reflex activity, weakness was measured as loss of maximum isometric torque, contracture was measured as the difference in range of motion between the affected and intact side, and limitations in physical activity were measured on a clinical scale. Results. The major independent contributors to contracture were spasticity for the first four months after stroke ( p 0.0001 - 0.10) and weakness thereafter ( p = 0.01 - 0.05). However, the major and only independent contributor to limitations in physical activity throughout the year was weakness ( p 0.0001 - 0.05). Conclusions. For the first time, from a longitudinal study, the findings show that spasticity can cause contracture after stroke, consistent with the prevailing clinical view. However, weakness is the main contributor to activity limitations.