Age-group Differences in the Performance of Selected Tests of Physical Function and Association with Lower Extremity Strength

Background and Purpose: It is not known whether short functional performance tests used in aging research are appropriate for use in healthy older adults. The purpose of this study was to investigate age-group differences (6th decade vs. 7th decade) in selected functional performance tests and the association between lower extremity strength and functional performance. Methods: One hundred and fifty nine (18.2% (n=29) male) healthy older (mean (standard deviation) age: 60.4 (5.3) years) adults were recruited from the University of Limerick Campus Community. Knee extensor (KE) peak torque (PT) was assessed from a maximal voluntary isometric contraction (MVC). Subsequently, participants completed 10m maximal and habitual gait speed tests, 5 repetition and 30-second chair rise tests and a 900m gait speed test. Results and Discussion: There was no difference in 10m gait speed between those in the 6th and 7th decade (P>0.05). Compared to the 6th decade, those in the 7th decade required an extra 39 seconds to complete 900m, an extra 0.6 seconds to complete 5 chair rises and performed 2 less chair rises in a 30-second time period (P<0.05). All tests had a weak association with KE strength (r=0.226 - 0.360; P<0.05), except for 900m gait speed which had a moderate association (r=-0.537; P<0.001). Our findings suggest that gait speed tests ≤10m cannot detect age-related difference in functional capacity when used in healthy older adults. Conclusion: Extended physical performance tests should be used in aging research on healthy older adults.