Test position and hip strength in healthy adults and people with chronic stroke.

Objective: To determine if peak torques generated by the hip flexors and extensors are dependent on test position in healthy adults and in people with chronic stroke.

Design: Cross-sectional study.

Setting: Motor performance laboratory.

Participants: Volunteers were 10 young (20.7+/-1.5y), 10 older adults (62.1+/-7y), and 10 stroke survivors (60.6+/-10y) who were an average of 5 years poststroke.

Interventions: Not applicable.

Main Outcome Measures: Isokinetic (60 degrees /s) peak concentric hip flexor and extensor torques (in Nm/kg) generated in supine and standing positions.

Results: Peak flexor torques measured in standing were generally higher than in supine (P=.018); a pattern evident in all groups, but significant only in stroke. An interaction between test position and group for hip extensor strength (P=.016) reflected 2 distinct patterns in which torques were highest in standing among the young subjects and highest in supine after stroke.

Conclusions: Isokinetic hip flexor and extensor strength measured in standing and supine are comparable in young and older healthy people. In chronic stroke, the test position may over or underestimate maximum peak torque depending on the muscle group tested, particularly on the side ipsilateral to the lesion. These findings may have implications for predicting functional ability from strength measurements.