[Purpose] The aim of this study was to examine the prevalence of knee pain in older farmers and to identify the associated factors, including the demographic variables, behaviours and physical activity/exercise levels. [Participants and Methods] A cross-sectional survey was conducted among a total of 285 systematically randomized farmers who were 60 years and older. [Results] The results of this study showed that the overall prevalence of knee pain in this population was 54.04% (n=154) based on a self-reported standardized Nordic Musculoskeletal Questionnaire. The highest prevalence of knee pain was 23.9% [95% confidence interval (CI): 17.75 to 30.05%] for two periods of time (within the past 7 days and over past 12 months). The intolerable physical activity risk factors that were significantly associated with knee pain included prolonged walking, standing and side sitting (odds ratio=2.39%, 95% CI: 1.06 to 5.39%). [Conclusion] The results of this study suggested that a high prevalence of knee pain in these older farmers may be particularly associated with sustaining a weight-bearing position.

[Purpose] We assessed the effects of a group intervention program used in home-dwelling elderly individuals to promote home exercise and prevent locomotive syndrome. [Participants and Methods] Pre- and post-intervention evaluations were performed in all participants. Group intervention was performed thrice between the pre- and post-intervention evaluations in all participants. A total of 19 elderly individuals participated in the pre- and post-intervention evaluations. Tests used for evaluation were the two-step test, standing-up test, and 25-question geriatric locomotive function scale. [Results] Among all participants in this study, 12 who performed all 3 aforementioned tests were classified as the non-absence group, whereas 7 who were absent more than once were classified as the absence group. We examined intergroup differences with respect to changes between the pre- and post-intervention evaluations, and we observed significant changes only in the results of the two-step test. [Conclusion] We conclude that low-frequency intervention in the form of workshops led to positive results with respect to improved physical function in home-dwelling elderly individuals.

[Purpose] Stand-and-ride personal mobility devices controlled by movements of the user’s center of gravity are used for balance training. We aimed to describe the physical activity required to operate this type of mobility device. [Participants and Methods] Eleven healthy males performed the following tasks: 1) moving their center of gravity forward or backward while standing on the floor (control task) and, 2) moving the mobility device forward or backward by moving their center of gravity (experimental task). [Results] We observed that the displacement of the center of gravity and the center of pressure, as well as angular displacements of the hips and knee joints, and maximum muscle activities of the biceps femoris, the medial head of the gastrocnemius and peroneus longus muscles were lesser during the experimental than during the control task. The distance moved by the device was significantly greater than the displacement of the user’s center of gravity during the experimental task. [Conclusion] We observed that moving the device forward or backward required lesser physical activity than that required to shift the user’s center of gravity forward or backward while standing on the floor. Additionally, we observed that even a small displacement of the user’s center of gravity produced a large displacement of the device. We concluded that during balance training, the greater and more easily perceived movement of the mobility device would provide helpful feedback to the user.

[Purpose] This study aimed to cross-sectionally examine the relationship between the practice of muscle-strengthening activities assessed according to Japanese and foreign physical activity guidelines and knee extensor strength in the elderly. [Participants and Methods] Overall, 223 (66 males and 157 females) participants aged ≥60 years were included. The questionnaire included four items on muscle-strengthening activities: undergoing strength training, performing vigorous farming and gardening, carrying heavy loads, and climbing stairs and hills. Thereafter, participant performance was classified as “sufficient” or “insufficient” based on whether they practiced each muscle-strengthening activity for ≥2 or <2 days a week, respectively. [Results] After the adjustment for age, gender, body mass index, physical activity level, and the practice of other muscle-strengthening activities, knee extensor strength was significantly higher in the elderly participants who sufficiently practiced strength training than in those who did not. Furthermore, those who sufficiently practiced farming and gardening had significantly higher knee extensor strength than those who did not. [Conclusion] Our findings suggest that the non-exercise muscle-strengthening activity of sufficient farming and gardening practiced according to physical activity guidelines is positively associated with knee extensor strength independent of other muscle-strengthening activities or the amount of physical activity in healthy elderly individuals.

[Purpose] This study aimed to clarify whether the morphological changes of the lower leg muscle occur equally in the longitudinal direction of the muscle according to changes in ankle joint position during sitting. [Participants and Methods] The participants were 15 healthy young females whose dominant lower legs were analyzed. The participants sat with the lower leg vertical to the floor with a neutral, dorsiflexed, or plantarflexed ankle position. Images were obtained from the fibular head from 290 mm distal using gravity magnetic resonance imaging. The muscle cross-sectional areas of the soleus, medial and lateral heads of the gastrocnemius, and anterior tibialis were measured. [Results] The muscle cross-sectional area of the soleus at the 1/4 proximal muscle belly in the plantarflexed position was greater than those in the other positions. The 1/4 distal part in the plantarflexed position was smaller than those in the other positions. The muscle cross-sectional area of the gastrocnemius at the 1/4 distal part in the plantarflexed position was smaller than that in the dorsiflexed position. In contrast, the muscle cross-sectional area of the tibialis anterior at the 1/4 proximal part in the dorsiflexed position was greater than those in the other positions, while that at the 1/4 distal part in the dorsiflexed position was smaller than that in the plantarflexed position. [Conclusion] In the sitting position, the morphological changes of the lower leg muscle according to changes in ankle joint position are not uniform in the longitudinal muscle direction.