Background: Not only the reduction of muscle strength or balance, but also the reduction of the agility are regarded as important factors of falls in elderly people. If an agility test for elderly people is established, the precision of the fall prediction rises and can be used for individual training. Objectives: To develop a new performance test focused on agility for elderly people and to evaluate the usefulness of this test. Design: Cross-sectional study. Setting: The Welfare Center of Kagami Town, Kagami Town Office, etc., Kochi, Japan. Participants: 828 community-dwelling, independent adults aged 20–99 years with no obvious cognitive or functional disability, were randomly recruited from Kagami town and the surrounding areas. Measurements: The Ten Step Test (TST, a new performance test), motor reaction time (MRT), knee extensor isometric strength, single leg standing time (SLST), and some other tests were used to evaluate the criterion-related validity and the content validity. TST was developed as a modified version of other step tests which require the subjects to place the whole foot on a block, then return it to the floor. In addition, female participants over 70 were asked whether or not they had fallen in the past year. Results: Excellent reliability for TST was found for interrelation (intra-class correlation coefficients, ICC = 0.96), and re-test reliability was sufficient (ICC = 0.86). Evidence for criterion-related validity was found through high single correlation with the timed supine-to-stand (r = 0.68) and high single correlation with MRT (r = 0.59). In addition, content validity was found through low correlation with knee extensor strength (–0.35) and SLST (–0.36) in 112 women over 70 years of age. The error rate by TST to predict falls (35.2%) was lower than the error rate by muscle strength (44.4%) and the balance (38.7%). TST confirmed decline after 50 years of age, and it conformed to a cubic curve. Conclusion: The findings indicate that TST is a reliable measure of agility, and it can help to predict the risk of falls. The decline of agility accelerates after 50 years of age. It shows that the decline of agility differs from the decline of leg muscle strength and balance.

Abstract.[Purpose] Agility includes three factors: rapidity of reaction, rapidity of directional change, and velocity of muscle contraction. We proposed the Ten-Step Test (TST) as a new performance test for agility. In our previous study, the criterion-related validity of TST was evaluated by comparing TST with a timed supine-to-stand test which reflects motion speed. However, timed supine-to-stand doesn't include rapidity of reaction. The purpose of this study was to evaluate the criterion-related validity of TST using motor reaction time (MRT).[Subjects] One hundred fifty-two community-dwelling adults were recruited.[Methods] TST requires the subjects to place one foot at a time, ten times on a block 10 cm in height while standing. TST was conducted twice, and the quickest time of the two trials was used for analysis. MRT was measured as the time between a touch on the malleous and the response of the ankle dorsi-flexion in a sitting position. For evaluating the relationship between TST and MRT, the conformity of the regression formulae of aging changes and correlation coefficients were analyzed. TST was also compared with the Functional Reach Test (FRT) and muscle strength of the knee.[Results] Both TST and MRT showed a quadratic rather than a linear relationship with age. The single correlation coefficient between TST and MRT was 0.59. [Conclusion] Age-related changes of TST and MRT showed a similar curve. These curves showed a significant increase after the age of 50, and the correlation coefficient between TST and MRT was high. The findings suggest that TST includes a factor related to motor reaction.

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[Purpose] To examine the ability of young and elderly individuals to control the timing and force of periodic sequential foot tapping. [Subjects and Methods] Participants were 10 young (age, 22.1 ± 4.3 years) and 10 elderly individuals (74.8 ± 6.7 years) who were healthy and active. The foot tapping task consisted of practice (stimulus-synchronized tapping with visual feedback) and recall trials (self-paced tapping without visual feedback), periodically performed in this order, at 500-, 1,000-, and 2,000-ms target interstimulus-onset intervals, with a target force of 20% maximum voluntary contraction of the ankle plantar-flexor muscle. [Results] The coefficients of variation of force and intertap interval, used for quantifying the steadiness of the trials, were significantly greater in the elderly than in the young individuals. At the 500-ms interstimulus-onset interval, age-related effects were observed on the normalized mean absolute error of force, which was used to quantify the accuracy of the trials. The coefficients of variation of intertap interval for elderly individuals were significantly greater in the practice than in the recall trials at the 500- and 1,000-ms interstimulus-onset intervals. [Conclusion] The elderly individuals exhibited greater force and timing variability than the young individuals and showed impaired visuomotor processing during foot tapping sequences.