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.

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 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.

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.

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.

The purpose of this study was to determine whether hand-grip strength (HGS) can be a significant discrimination factor of mobility limitation (ML) among older adults. Cross-sectional analysis was conducted on data from 939 community-dwelling older adults, aged 65-96 years (74.4 ± 6.4 yr, 266 men, 673 women). ML was defined as self-reported difficulty in walking 400 m, climbing 10 steps, and rising from a chair. Trained testers assessed standardized measurements of HGS and lower extremity performance score (LEPS) calculated by four tests (i.e., tandem stance, 5-chair sit-to-stand, alternate step, and timed up & go). Receiver operating characteristic (ROC) analysis was conducted to identify discrimination power of HGS and LEPS for ML. The areas under the ROC curves (AUCs) of HGS and LEPS for ML were 0.82 and 0.87 in men; 0.70 and 0.85 in women, respectively. No significant difference was detected between the AUCs of HGS and LEPS (P = 0.12) in men, whereas in women, the AUC was significantly lower in HGS than LEPS (P < 0.001). The optimal HGS cut-off values for ML were 31.0 kg (sensitivity 75%, specificity 81%) for men and 19.6 kg (sensitivity 73%, specificity 57%) for women. In men, the HGS test could be as useful as LEPS for identifying ML. In women, discrimination power for ML by HGS alone was considered acceptable; however, a combination of HGS and lower extremity performance tests could be more useful for monitoring the hierarchical levels of physical frailty.

Recently, the problem of the high incidence of throwing injuries in young people has been gaining attention. Identifying high-risk players before the onset of the throwing injury is important for prevention. One of the most widely used screening tests for sports-related injuries is the Functional Movement Screen (FMS), which assesses the quality of movement; however, its correlation with throwing injuries has not been established. The purpose of this study was to investigate the correlation between the FMS score and throwing injuries. The FMS was used during the medical check for two hundred and thirty junior high school baseball players. We allotted those who had experienced throwing injuries multiple times to the injury group and those who had never experienced throwing injury to the control group. We then calculated the FMS cutoff value using the receiver operating characteristic curve. In addition, we investigated differences in the incidence of throwing injury between above and below the cutoff value using chi-square test. The FMS cutoff score was 17. Players who scored ≤17 had a significantly higher incidence of throwing injuries than those who scored ≥18. Conclusion: We believe that FMS score is correlated to throwing injuries. In addition, the results suggest that throwing injuries might be prevented in junior high school baseball players who scored ≤17 on the FMS if they undergo training in the correct movement patterns.