A stair-climbing test for measuring mechanical efficiency of ambulation in adults with chronic stroke

Abstract

Purpose: Mechanical efficiency can assess motor performance in individuals with physical disabilities. The purpose was to determine the utility of predicting it from heart rate (HR) during a self-paced stair-climbing test in adults with chronic hemiparesis after stroke and to determine the minimal detectable change of net mechanical efficiency (ME_net) measured by this exercise. Methods: First, 15 subjects with chronic hemiparesis participated in a validation study (A) and then 28 took part in a repeatability study (B). In study A the ME_net was calculated from external work and oxygen uptake above rest (dVO₂), as directly measured and as predicted from body weight and increase in heart rate (dHR). In study B, predicted dVO₂ was used to obtain ME_net for duplicate stair-climbing tests (T1, T2) with >30 min rest between. Results: Measured ME_net was closely related to predicted ME_net (r = 0.97, p < 0.001). In study B predicted ME_net for T2 and T1 were closely related (r = 0.91, ICC = 0.90). Conclusion: With a minimal detectable change of 0.6% (0.053 of average ME_net score of 10.4%), ME_net values from the stair-climbing test seem sufficiently meaningful to estimate ambulatory ability and its changes with interventions or walking aids in adults with hemiparesis.

Implications for Rehabilitation

• Ambulatory ability can be estimated from mechanical efficiency, obtained from a 5-min stair-climbing test utilizing a 4-step stair, to measure external work, and the change in heart rate above rest to estimate the metabolic cost of the task.

• A change of > 0.6% in mechanical efficiency by this stair-climbing test indicates a significant change in ambulatory ability of persons with hemiparesis.

• Chronic hemiparesis
• mechanical efficiency
• minimal detectable change
• stair-climbing test repeatability
• stair-climbing test validation

Acknowledgements

We appreciate the cooperation and special donation of time and energy provided by the 44 participants in this study.

Declaration of interest

This material is based on work done in part of a multi-center intervention study conducted in the Middle East and Italy (Registered in the USA with NIH Clinical Trials.gov identifier NCT01466296). The study was partially funded by Regione Lombardia, Italy D 4092 del 27/04/2009.

We confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.