Research

Standardized voluntary force measurement in a lower extremity rehabilitation robot

Marc Bolliger^1,2 , Raphael Banz¹ , Volker Dietz¹ and Lars Lünenburger¹

¹  Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland

²  Sensory-Motor Systems Laboratory, ETH Zurich, Switzerland

author email corresponding author email

Journal of NeuroEngineering and Rehabilitation 2008, 5:23doi:10.1186/1743-0003-5-23

Published:	28 October 2008

Abstract

Background

Isometric force measurements in the lower extremity are widely used in rehabilitation of subjects with neurological movement disorders (NMD) because walking ability has been shown to be related to muscle strength. Therefore muscle strength measurements can be used to monitor and control the effects of training programs. A new method to assess isometric muscle force was implemented in the driven gait orthosis (DGO) Lokomat. To evaluate the capabilities of this new measurement method, inter- and intra-rater reliability were assessed.

Methods

Reliability was assessed in subjects with and without NMD. Subjects were tested twice on the same day by two different therapists to test inter-rater reliability and on two separate days by the same therapist to test intra-rater reliability.

Results

Results showed fair to good reliability for the new measurement method to assess isometric muscle force of lower extremities. In subjects without NMD, intraclass correlation coefficients (ICC) for inter-rater reliability ranged from 0.72 to 0.97 and intra-rater reliability from 0.71 to 0.90. In subjects with NMD, ICC ranged from 0.66 to 0.97 for inter-rater and from 0.50 to 0.96 for intra-rater reliability.

Conclusion

Inter- and intra- rater reliability of an assessment method for measuring maximal voluntary isometric muscle force of lower extremities was demonstrated. We suggest that this method is a valuable tool for documentation and controlling of the rehabilitation process in patients using a DGO.