Development of a Position-Specific Index of Muscle Strength to be Used in Stroke Evaluation

Abstract 

Moriello C, Mayo NE. Development of a position-specific index of muscle strength to be used in stroke evaluation.

Objective

To develop a position-specific index of muscle strength for individuals with stroke.

Design

Cross-sectional design.

Setting

A major teaching hospital in a Canadian urban city.

Participants

Sixty-three patients with poststroke onset between 3 and 12 months.

Interventions

Not applicable.

Main Outcome Measure

The muscle strength of the lower-extremity muscles was tested bilaterally in multiple positions using hand-held dynamometry.

Results

A principal components analysis resulted in grouping the muscles of the affected and unaffected sides of the gravity related and gravity eliminated positions into 5 indices. The 5 indices were moderately to highly correlated (r² range, .59−.81) with each other and so were combined into 1 global index. The gravity related muscle strength on the affected side was, on average, 85% of the unaffected side (range, 37%–157%); the gravity eliminated muscle strength of the affected side was, on average, 92% of the unaffected side (range, 53%–121%).

Conclusions

This study resolves the methodologic issue of how to summarize multiple data points that relate to one construct, namely, strength of different muscle groups assessed in several positions.

Key Words: Lower extremity, Muscles, Rehabilitation, Stroke