R esearchers studying human movement have attempted to define skilled motor performance by employing a range of kinematic variables, such as movement speed, movement time, timing accuracy, etc. In recent research, temporal and spatial intrasubject variability in kinematic variables is regarded as an important measure of motor skill and practice effects. Intrasubject variability of kinematic variables is an index of movement consistency or stability and thereby provides us with a measure to evaluate motor skill for a given task (8).The variability was examined in human gait, in particular, for its temporal and spatial parameters. It was expected that stability of gait could be assessed using the variability measure, especially for older persons (3-5) and physically disabled subjects (1). In fact, there was a negative correlation between variability in step width and balance performance for women 60 years of age and over (5) and also an increased variability in step length for hospitalized fallers compared with nonfallers (4). The results suggest that the variability measure can be an index of stability of gait performance.These studies, however, measured variability in the gait parameters at the preferred speed of each subject. Maruyama and Nagasaki (8) for treadmill walking of normal s u b jects that intrasubject variability in the duration of every walking phase decreased with increased speed, thereby supporting the hypothesis that faster movement is more consistent than slower movement. Furthermore, they showed that the coeficients of variation (CV) were the lowest at the specific step rates (cadence) that were linearly dependent on walking speed. The relationship between speed and step rate for walking with the lowest temporal CV was very close to the speed-rate relationship found in free walk. They suggested that stability of gait in terms of CV for the duration of the walking phase was optimal for walking with a freely chosen step rate at any given speed.There is also an optimal method of walking, both in terms of energy cost and attentional demand. At preferred walking speed, energy consumption per unit of distance was at a minimum (13). Furthermore, freely chosen step rates required the least oxygen consumption at a given speed (6,17). Kurosawa (7) measured reaction time to a probe during treadmill walking and demonstrated that walking at a subject's preferred speed called for a minimum attentional de-

BackgroundThe fastest growing age group globally is older adults, and preventing the need for long-term nursing care in this group is important for social and financial reasons. A population approach to diet and physical activity through the use of social services can play an important role in prevention. This study examined the effectiveness of a social health program for community-dwelling older adults aimed at introducing and promoting physical activity in the home at each individual’s pace, helping participants maintain good dietary habits by keeping self-check sheets, and determining whether long-standing unhealthy or less-than-ideal physical and dietary habits can be changed.MethodThis cluster randomized trial conducted at 6 community centers in an urban community involved 92 community-dwelling older adults aged 65–90 years. The intervention group (3 community centers; n = 57) participated in the social health program “Sumida TAKE10!” which is an educational program incorporating the “TAKE10!® for Older Adults” program, once every 2 weeks for 3 months. The control group (3 community centers; n=35) was subsequently provided with the same program as a crossover intervention group. The main outcome measures were changes in food intake frequency, food frequency score (FFS), dietary variety score (DVS), and frequency of walking and exercise. The secondary outcome measures were changes in self-rated health, appetite, and the Tokyo Metropolitan Institute of Gerontology (TMIG) Index of Competence score.ResultsCompared to baseline, post-intervention food intake frequency for 6 of 10 food groups (meat, fish/shellfish, eggs, potatoes, fruits, and seaweed), FFS, and DVS were significantly increased in the intervention group, and interaction effects of FFS and DVS were seen between the two groups. No significant differences were observed between baseline and post-intervention in the control group. Frequency of walking and exercise remained unchanged in both groups, and no significant difference in improvement rate was seen between the groups. Self-rated health was significantly increased in the intervention group. Appetite and TMIG Index of Competence score were unchanged in both groups.ConclusionsThe social health program resulted in improved dietary habits, as measured by food intake frequency, FFS, and DVS, and may improve self-rated health among community-dwelling older adults.Trial registration numberUMIN000007357

Background  A population‐based prospective cohort study was undertaken to examine the predictors of functional decline in instrumental activities of daily living (I‐ADL) among non‐disabled older Japanese subjects living in a rural community during a five‐year interval from 1992 to 1997. Methods  The subjects consisted of 624 men and women aged from 65–89 years and independent in I‐ADL at baseline, who could be completely followed for five years. Independent variables were various physical factors potentially associated with higher level of functional capacity obtained from an interview survey and medical examinations at baseline. Dependent variables were functional status in I‐ADL obtained at the time of the 5‐year follow‐up. Results  Significant predictors of functional decline in I‐ADL during a 5‐year follow‐up period included: (1) older age; (2) higher blood pressure; and (3) lower maximum walking speed at baseline. Among these predictor, the maximum walking speed is likely to the strongest predictor for the decline in I‐ADL. Conclusion  The ability to walk faster in the old age is strongly associated with independence in the other I‐ADL, and walking speed should be modified by the lifestyle to strengthen muscles of the lower extremities in daily life.

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Working might be protective from a decline in BADL only for men, but not for women. Regarding the difference of sex roles in conventional Japanese society, working would be an effective solution especially for men to participate in social activities.