Alternatives for measuring knee extension strength of the elderly at home.
OBJECTIVE
To examine the construct validity of three measures of knee extension strength obtained from elderly individuals.


METHODS
Retrospective and cross-sectional.


METHODS
Home care.


METHODS
Forty-one consecutively treated patients (mean age 79.2 years).


METHODS
Knee extension strength was measured using manual muscle testing, hand-held dynamometry, and the sit-to-stand test.


RESULTS
Convergent construct validity was supported by the significant correlations between the measures (rs = 0.578-0.702). Discriminant construct validity was confirmed by the finding of significant differences in the manual muscle test scores and in the hand-held dynamometer measures of patients who were unable versus able to stand from a chair without the upper extremities or help. The sensitivity of the two measures for discriminating between patients able versus unable to stand from a chair was 90.9% for manual testing and 68.2% for dynamometry. The specificity was 78.9% for manual testing and 94.7% for dynamometry.


CONCLUSIONS
The results of this study show that the three measures employed to characterize knee extension strength are valid when employed with elderly patients in a home care setting.
Bohannon
R W
RW
Department of Physical Therapy, School of Allied Health, University of Connecticut, Storrs 06269, USA.
D000368:Aged; D005260:Female; D006699:Home Care Services; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D008722:Methods; D018482:Muscle, Skeletal / Q000502:physiology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity