In this study, we performed a logistic regression analysis according to the frequency of participation in social leisure activities (education, clubs, social groups, volunteer activities, religious activities, and senior citizens’ welfare center use) by men and women aged ≥ 65 years. We investigated the frequency of participation in social leisure activities and their association with the level of frailty (health vs. pre-frailty, health vs. frailty, pre-frailty vs. frailty). This study included 10,297 older adults (men: 4128, women: 6169) who participated in the 2017 National Survey of Older Koreans, and were divided into three groups (healthy, pre-frailty, and frailty). Five frailty index components were used to measure the frailty level. There was a positive relationship between the elderly’s religious activities, four times a week, from the healthy stage to the frailty stage, from the healthy stage to the pre-frailty stage, and from the pre-frailty stage to the frailty. In addition, positive associations emerged in leisure activities and club activities, respectively, from the healthy stage to the frailty stage (once a week, respectively). Positive association also emerged from the healthy stage to the pre-frailty and from the pre-frailty stage to the frailty stage (once a month to once in a two-week period).

User-friendly rehabilitation medical devices can enhance health and the quality of life through the convergence of information communication and medical technology. Muscle contraction enables bodily movement, and the assessment of muscle strength is crucial. Muscle contraction includes isometric, isotonic, and isokinetic types. Many individuals with physical disabilities rely on wheelchairs due to lower-limb paralysis. There is a substantial correlation between the level of upper-limb functional recovery and the quality of daily life. This study aimed to design and evaluate a device that utilizes various muscle contractions to enhance the effectiveness of upper-limb rehabilitation exercises. The results from the isometric performance assessment showed percentage error rates of >30% for 5–30 kg. Correction equations were employed, and the isometric performance assessment resulted in error rates below 2.1% for 5–30 kg. Isokinetic performance assessment using video analysis evaluated a consistent wire speed from 10 cm/s to 70 cm/s with an average error rate of 0.91% across all speeds. This study demonstrates the ability to accurately measure various muscle contractions and showcases the potential for real-time feedback. This highlights how such a device could be helpful for target groups, including older adults and individuals with disabilities, during upper-limb rehabilitation exercises.

Background/Objectives: Frailty-related vulnerability spans health, physical function, health behaviors, cognition, and psychological well-being. A single summary score may not fully convey how these features co-occur within individuals. This study identified data-driven frailty-related profiles among community-dwelling older adults and compared the magnitude of between-profile differences. Methods: We conducted a cross-sectional secondary analysis of the 2023 National Survey of Older Koreans. The analytical sample included 9950 participants. Ten indicators—self-rated health, chronic disease count, 1-year weight loss, sleep quality, weekly exercise frequency, fatigue, stair-climbing ability, 300-m walking ability, cognitive function, and depressive symptoms—were standardized and entered into K-means clustering. Candidate solutions for K = 2–10 were evaluated using within-cluster sums of squares and mean silhouette coefficients. Profile characteristics and effect sizes were compared using independent-samples t-tests, Pearson’s chi-squared tests, Cohen’s d, and Cramér’s V. Results: The K = 2 solution had the highest mean silhouette coefficient (0.273) among the candidate solutions, indicating modest separation between clusters. Within the analytical sample, 6962 participants (70.0%) formed a lower-vulnerability profile and 2988 (30.0%) a multidimensional higher-vulnerability profile. The latter profile showed less favorable health, functional, psychological, and cognitive characteristics. Among the cluster-defining indicators, the largest descriptive differences were observed in 300-m walking (d = 2.013) and stair-climbing ability (d = 2.001). Conclusions: The two clusters represented a relative multidimensional vulnerability gradient rather than clearly distinct clinical phenotypes. Although the findings describe co-occurring vulnerability characteristics, their potential clinical utility requires independent and longitudinal validation.

Equipment with integrated sensing can now provide repetition-velocity feedback without external sensors. However, whether their output agrees with that of established commercial linear position transducers has yet to be investigated. This study addresses this gap by comparing repetition-velocity measurements obtained from the motor-integrated magnetic sensing system of MOTY V with those obtained from GymAware RS to evaluate inter-device agreement and measurement characteristics. Deadlifts and squats were performed at 40%, 60%, and 80% of estimated one-repetition maximum by 15 male students, with both devices simultaneously measuring bar movement. The final analysis included 897 paired repetitions out of 900 planned pairs. Mean velocities were 0.7102 ± 0.1496 m/s for MOTY V and 0.6816 ± 0.1410 m/s for GymAware RS. The mixed-effects mean bias (MOTY V–GymAware RS) was 0.0285 m/s (95% confidence interval [CI], 0.0216–0.0353), with repeated-measures 95% limits of agreement ranging from −0.0773 to +0.1342 m/s. Mean absolute error and root mean square error were 0.0467 and 0.0609 m/s, respectively. Repetition-level correlation was r = 0.933, and set-level absolute-agreement intraclass correlation coefficient (ICC) was 0.958 (95% CI, 0.929–0.973). Mean bias did not differ significantly by exercise, load, or their interaction, whereas proportional bias was significant (β = 0.125, p < 0.001). MOTY V showed high agreement with GymAware RS, but small positive systematic and proportional biases preclude assuming direct interchangeability.

Background/Objectives: Frailty-related vulnerability spans health, physical function, health behaviors, cognition, and psychological well-being. A single summary score may not fully convey how these features co-occur within individuals. This study identified data-driven frailty-related profiles among community-dwelling older adults and compared the magnitude of between-profile differences. Methods: We conducted a cross-sectional secondary analysis of the 2023 National Survey of Older Koreans. The analytical sample included 9,950 participants. Ten indicators—self-rated health, chronic disease count, 1-year weight loss, sleep quality, weekly exercise frequency, fatigue, stair-climbing ability, 300-m walking ability, cognitive function, and depressive symptoms—were standardized and entered into K-means clustering. Candidate solutions for K = 2–10 were evaluated using within-cluster sums of squares and mean silhouette coefficients. Profile characteristics and effect sizes were compared using independent-samples t-tests, Pearson’s chi-squared tests, Cohen’s d, and Cramér’s V. Results: The K = 2 solution had the highest mean silhouette coefficient (0.273). Within the analytic sample, 6,962 participants (70.0%) formed a lower-vulnerability profile and 2,988 (30.0%) a multidimensional higher-vulnerability profile. The latter profile showed less favorable health, functional, psychological, and cognitive characteristics. The largest between-profile differences occurred in 300 m unassisted walking (d = 2.013) and climbing 10 stairs without assistance (d = 2.001), followed by self-rated health (d = 1.582), and depressive symptoms (d = 1.418). Conclusions: The two profiles reflected relative multidimensional vulnerability differences within the analytical sample rather than predefined clinical frailty categories. Multidimensional assessments may provide complementary information for older adult healthcare, although external and longitudinal validation is needed before broader clinical application.

Background/Objectives: Self-reported function, exercise behavior, and performance-based fitness describe related but distinct aspects of health in later life. This study compared their age- and sex-specific descriptive profiles using independent Korean datasets. Methods: The 2023 National Survey of Older Koreans contributed 9951 self-respondents; the 2023 National Fitness Award (NFA) dataset contributed 27,440 assessment records, which may not represent 27,440 unique individuals. Age-by-sex profiles were analyzed separately; no individual-level linkage or direct between-dataset statistical comparison was performed. Results: Stair-climbing and 300 m walking limitations, and related objective performance indicators, generally showed less favorable values in older age groups. Exercise non-participation followed a less consistent pattern. Among men, the weighted prevalence was 47.16% (95% CI 43.29–51.04%) at ages 65–69 and 40.88% (36.64–45.13%) at ages 75–79; their exploratory age-group contrast did not remain significant after Holm adjustment (adjusted p = 0.066). Among women, non-participation was 42.47–45.67% across ages 65–79. Conclusions: The observed directional similarities are descriptive and cannot establish agreement, predictive validity, or the effects of exercise at the individual level. Exercise participation reports, task-specific difficulty questions, and objective fitness tests should be regarded as distinct information sources requiring evaluation within the same individuals.