Reliability of simple portable tests of physical performance in older people after hip fracture.

OBJECTIVE: To investigate the test-retest reliability of measures of strength, balance, gait and functional performance when used with older people following hip fracture.
SUBJECTS: Thirty people (16 hospital inpatients and 14 community dwellers).
DESIGN: Subjects underwent two assessments: one day apart for the hospital inpatients and one week apart for the community dwellers. MEASUREMENT: Strength (dynamometer, sphygmomanometer, spring balance, lateral step-up ability), balance (sway-meter, Functional Reach Test, single leg stance time, Step Test), gait (timed 6-m walk with steps taken, base of support and step length), and functional performance (PPME total score and timed supine-to-sit and sit-to-stand) were measured.
RESULTS: Eleven of the 14 continuously scaled measurement tools achieved excellent reliability (intraclass correlation coefficient (ICC) > 0.75) for one or more tests. A hand-held dynamometer was found to be the tool with the highest test-retest reliability for measuring hip muscle strength (ICC (3,1) 0.86 for affected hip abduction). For measurement of knee extension strength, a spring balance (ICC (3,1) 0.94 affected leg) was the most reliable. For testing balance, the Step Test (ICC (3,1) 0.94 for stepping with affected leg) and Functional Reach Test (ICC (3,1) 0.89) had the highest test-retest reliability. The ICC (3,1) values were 0.97 for walking velocity (comfortable pace) and 0.96 for the total score of the Physical Performance and Mobility Examination.
CONCLUSION: The test-retest reliability of a number of simple measures of physical performance is excellent when used with this population.