Although the physical activity reference value for older adults (10 METs*hour/week) has been promoted by Japan Ministry of Health, Welfare, and Labour since 2013, little is known about how many steps/day cut-off values that optimally identify meeting the reference value according to the differences of age, sex, medical history, and joint pain. The purpose of this study were 1) to determine the steps/day that optimally identify meeting the reference value, and 2) to identify the differences by the effects of age, sex, medical history, and joint pain on cut-off values. This study included 583 community-dwelling older Japanese adults (aged 73.2 ± 5.4 years; 153 men, 430 women). A uniaxial accelerometer survey was conducted to estimate the total physical activity volume and steps/day. Receiver operating characteristic (ROC) analyses were used to detect steps/day cut-off values for meeting the reference value among all participants and stratified by age, sex, medical history, and joint pain. The optimal cut-off value (AUC (area under the ROC curve), sensitivity, and specificity) for the reference value was 4376 steps/day (0.99, 95.2%, and 97.2%) in all participants. Differences among the cut-off values according to age, sex, medical history, and joint pain ranged from 39 to 169 steps/day. These results suggest that step counts has satisfactory validity to represent the reference value in older adults, and the effects of age, sex, medical history, and joint pain on cut-off values were considerably small. Therefore, this step-count level may be a useful indicator for modifying the daily-life activities of older adults.

The purpose of this study was to examine the effects of an exercise intervention for older married couples on exercise adherence and physical fitness. Thirty-six older married couples and 61 older adults participated in the study as couple and non-couple groups (CG, NCG, respectively). Participants attended an exercise class once a week and performed a home-based exercise program consisting of walking and strength exercise over eight weeks. Exercise adherence was assessed by the rate of non-absentee, walking habits (≥ 2 times/week), and strength exercise habits (≥ 6 items*2 sets/week). Physical fitness was assessed by the Senior Fitness Tests. Logistic regression analyses were conducted to obtain the CG’s odds ratios (ORs) and 95% confidence interval (CI) for non-absentee, walking habits, and strength exercise habits (reference: NCG). Analyses of covariance were used to examine the statistical difference in the degree of change (⊿) for physical fitness between CG and NCG. CG had significantly higher ORs for non-absentee and walking habits compared with NCG but there was no significant difference in the rate of strength exercise habits between the two groups. In regards to ⊿ for physical fitness, significantly higher ⊿ for upper extremity strength was observed in CG than in NCG, while there were no significant differences in ⊿ for other physical fitness items between the two groups. These results suggest that an exercise intervention for older married couples would be more useful to maintain higher participation in exercise program and walking and improving upper extremity strength.

This study aimed to examine the association between body mass index (BMI) and muscle strength, and mobility limitation (ML). A cross-sectional analysis was conducted on data from 570 community-dwelling older Japanese women aged 65-91 years [mean age, 73.9 ± 5.8 (SD) years]. Muscle strength was assessed by hand-grip strength (HGS). ML was assessed using self-reported difficulty level in walking 400 m and ascending 10 steps without resting. BMI and muscle strength were divided into tertiles (high: BMI ≧ 25.1 kg/m², HGS ≧ 22.5 kg; middle: BMI 22.4-25.0 kg/m², HGS 18.8-22.4 kg; low: BMI ≦ 22.3 kg/m², HGS ≦ 18.7 kg) respectively, and logistic regression analysis was used to determine the association between BMI and muscle strength with ML. 256 participants (44.9%) were identified as having ML. Adjusted odds ratios of BMI for ML were 1.64 (95% confidence interval (CI): 1.00-2.68) in the middle group and 1.89 (95% CI: 1.15-3.12) in the high group when compared to the low group. Adjusted odds ratios of muscle strength for ML were 1.25 (95% CI: 0.77-2.04) in the middle group and 1.85 (95% CI: 1.11-3.09) in the low group when compared to the high group. Compared to the low BMI plus high muscle strength group, adjusted odds ratio for ML was significantly higher in the high BMI plus low muscle strength group (2.65, 95% CI: 1.02-6.87) and the high BMI plus middle muscle strength group (3.09, 95% CI: 1.25-7.61). Our findings indicate that the combination of overweight plus muscle weakness is more predictive for having ML than overweight or muscle weakness alone.

The purpose of this study was to examine the association between the hierarchy of higher-level functional capacity (instrumental self-competence, intellectual activity, social role) and the quantity of physical activity in older women (n = 175, 72.1 ± 5.8 years). Physical activity was estimated with a uniaxial accelerometer that calculated light-intensity physical activity (LPA), and moderate-to vigorous-intensity physical activity (MVPA). Higher-level functional capacity was assessed with the Tokyo Metropolitan Institute of Gerontology (TMIG) index of competence. According to the three subscales (instrumental self-competence, intellectual activity, and social role) of the TMIG index, participants who reported a score of 1 or more below the respective full marks were categorized as a group with reduced status. Logistic regression analysis was conducted to examine association between the hierarchy of higher-level functional capacity and the quantity of physical activity divided by intensity of activity, adjusted by covariance. Only low MVPA showed a significantly lower odds ratio than high MVPA in reduced status of instrumental self-competence. Since instrumental self-competence was significantly related with only the quantity of MVPA, it may be more important to focus on “quantity” of physical activity to prevent reductions in higher-level functional capacity in advanced stages of declining functional capacity.

Habitual moderate- to vigorous-intensity physical activity positively impacts lower extremely performance in older adults. However, little is known whether habitual sedentary behaviour time independently impacts lower extremity performance. The purpose of this cross-sectional study was to identify whether sedentary behaviour time is associated with lower extremity performance independent of moderate- to vigorous-intensity physical activity time in older adults. Eight-hundred-and-two community-dwelling older Japanese adults (72.5 ± 5.9 years) participated in this study. Sedentary behavioir time and moderate- to vigorous-intensity physical activity time were assessed using a uniaxial accelerometer. Lower extremity performance was assessed by repeated chair stand, single leg stance, and timed up and go tests. Jonckheere terpstra trend test and Spearman rank correlation coefficient were used to identify the single relation between sedentary behaviour time and lower extremity performance. A hierarchical multiple regression analysis was used to identify whether sedentary behaviour time is associated with lower extremity performance independent of moderate- to vigorous-intensity physical activity time. Results of single relation analysis showed there were negative associations between sedentary behaviour time and all lower extremity performance tests. Multivariable analysis indicated that sedentary behaviour time was not significantly associated with any lower extremity performances but moderate- to vigorous-intensity physical activity time was positively associated with all lower extremity performance tests. In conclusion, sedentary behaviour time would be less useful than moderate- to vigorous-intensity physical activity time as an indicator for modifying habitual behavior to maintain good lower extremity performance in community-dwelling older adults.

The purpose of this study was to retrospectively examine the association of habitual exercise with “single fall (= 1)”, “multiple falls (≥ 2)”, and “injurious falls (≥ 1)” among community-dwelling older adults. A total of 1,683 community-dwelling older adults, aged 60-97 years (72.6 +/- 6.6 yr, 512 men and 1,171 women) were included in this study. Habitual exercises continued one year or longer (6.4 +/- 9.5 yr) were classified into twelve types. Exercise components (time, quantity, period of continuity, and number of exercises) were divided with median or tertiles. To assess the association between habitual exercises and fall status, multivariable logistic regression analyses with stepwise selection method, were applied. The multivariable logistic regression analyses showed that dance (odds ratio (OR): 0.30, 95% confidence interval (CI): 0.09-0.96) was negatively associated with “single fall”. Bicycling (OR: 3.72, 95% CI: 1.32-10.77) was positively associated with “multiple falls”, and the period of continuity (OR: 0.74, 95% CI: 0.60-0.91) was negatively associated with “multiple falls”. None of the exercise components were selected with regard to “injurious falls”. Results indicate that dance may be an effective type of exercise for fall prevention among community-dwelling older adults. However, caution about falling is warranted toward bicycling as an exercise. Moreover, a longer period of continuity (≥ 4 years) appears to be a positive factor of habitual exercise for fall prevention.

Fall-related factors (FRFs) are classified into intrinsic factors and extrinsic factors. Intervention programs, which focused on modifiable factors (MFs) among FRFs have been designed to prevent falls. The purpose of this study was to identify easily-measurable intrinsic MFs for falls and recurrent falls. Cross-sectional analysis was carried out on the data from 483 community-dwelling older adults, aged 65-92 years (73.7 ± 5.9 yr, 138 men, 345 women). We measured history of falls in the past year and 7 domains of FRFs. Of these, 20 items were selected as MFs. Analyses of FRFs and MFs were conducted by comparing (separated by sex) those who did not report a fall with those who reported any number of falls, and those who reported no falls or one fall with those who reported recurrent falls. Using the significant items as independent variables, multiple logistic regression analysis with forward selection method was performed. The prevalence of falls and recurrent falls was: in men, 24.6% and 14.5%; in women, 26.7% and 12.5%. There were no significant differences in prevalence of falls or recurrent falls between genders. The following items were selected as the MFs most strongly associated with falls: climbing 10 steps with difficulty and tandem walk; and associated with recurrent falls: climbing 10 steps with difficulty, sit and reach, and tandem walk. These results are useful in determining the focus of fall prevention programs to be used in future community-based interventions.

The purposes of this study were (i) to determine the characteristics of physical function for frail older adults, compared with those for the independent and the dependent, (ii) to examine validity of the “health check-up questionnaire” (Kihon Check-list: CL) for finding frail older adults. Five hundred thirty-nine older Japanese people (75.5 ± 7.0 years) were assigned to each one of the three categories: the independent, the frail and the dependent according to the classification criteria of long-term care insurance system. Physical function score (PFS) was estimated by principal components analysis. Logistic regression analysis was conducted to assess validity of the CL and to examine the screening tool for detecting frail older adults who have a higher risk for becoming the dependent. Significant differences were observed among the three groups in PFS (the independent, 0.580 ± 0.467; the frail, -0.309 ± 0.733; the dependent -1.347 ± 0.949). The Odds ratio (OR) of the dependent for older adults to whom the CL was applied was 2.4 (95% confidence interval (CI): 1.3 - 4.5), and the OR for those to whom both the CL and the hand-grip strength test were applied was 5.4 (2.6 - 11.5). These data suggest that the comprehensive status of physical function of frail older adults, which varied widely, was intermediate between the independent and the dependent. It is useful to add the hand-grip strength test to the CL as a screening tool to subdivide frail older adults.

BACKGROUND: The purpose of this study was to examine the association between habitual walking and multiple or injurious falls among community-dwelling older adults. METHODS: Cross-sectional analysis was conducted on the data from 708 community-dwelling older adults, aged 60-91 years (72.3 +/- 6.6 yr, 233 men and 475 women). Prevalence of falls between walkers and non-walkers was compared separately by the number of risk factors (Groups R0, R1, R2, R3 and R4+). Logistic regression analysis was used to assess the association between habitual walking and falls separately by lower (R<3) and higher (R3+) risk groups. An interaction between habitual walking and risk of falling was examined in logistic regression analysis among all participants. RESULTS: In Groups R0, R1 and R2, prevalence of falls was lower in walkers than non-walkers; however, in Groups R3 and R4+, prevalence of falls was higher in walkers. Logistic regression analysis showed that habitual walking was significantly associated with fewer falls (Odds ratio (OR): 0.44, 95% confidence interval (CI): 0.20-0.97) among the lower risk group, but significantly associated with greater falls (OR: 4.61, 95% CI: 1.32-16.09) among the higher risk group. The interaction between habitual walking and higher risk of falling was significant (P < 0.05). CONCLUSION: Habitual walking seems to positively affect the prevention of multiple or injurious falls but only in community-dwelling older adults who have less than three risk factors.