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The purpose of this study was to estimate sex differences in age-related grip strength decline and describe the course of decline in grip strength from age 40 to 89 years by a longitudinal epidemiological study. Participants were randomly selected community-living men (n = 648) and women (n = 598) aged 40 to 79 years at baseline. Grip strength was measured with standard techniques every other year over a 10-year period. The preservation rate of grip strength was calculated as the 10-year follow-up value divided by the baseline value. The relationship between the preservation rates of grip strength and age group (by decade) at baseline by sex was analyzed using Two-Way Analysis of Variance and the Tukey-Kramer method. The trajectories of grip strength over 10 years were plotted for both men and women. The mean grip strength preservation rates of participants in their 40s, 50s, 60s and 70s over 10 years was 0.90, 0.88, 0.84 and 0.79 in men, and 0.89, 0.89, 0.89 and 0.88 in women, respectively. There were significant differences in sex and age group at baseline in the preservation rate of grip strength. Among men, the preservation rate of grip strength for the 70s group was significantly lower than that of younger groups (p < 0.05); however, no significant difference was observed among age groups in women. The trajectories of grip strength decline year by year were steep in men, but even in women. Age-related decline in grip strength markedly increased in older men, but remained constant throughout middle and late adulthood in women.

AIM: To evaluate the potential improvement of fall prevention awareness and home modification behaviors and to decrease indoor falls by applying a home hazard modification program (HHMP) in community-dwelling older adults followed up to 1 year in this randomized controlled trial. METHODS: The present authors randomly assigned 130 older adults living in the Tokyo metropolitan region to either the HHMP intervention group (n = 67) or the control group (n = 63). Both groups received four, 2 h fall prevention multifactorial programs including education regarding fall risk factors, food and nutrition, foot self-care, and exercise sessions. However, only the HHMP group received education and practice regarding home safety by using a model mock-up of a typical Japanese home. RESULTS: The mean age of the HHMP group was 75.7 years and the control group 75.8. The HHMP group showed a 10.9% reduction in overall falls, and falls indoors showed an 11.7% reduction at 52 weeks. Those aged 75 years and over showed a significant reduction in both overall falls and indoor falls at 12 weeks. Fall prevention awareness and home modifications were significantly improved in the HHMP group. CONCLUSION: HHMP has the potential to improve fall prevention awareness and home modification behaviors, and specifically decreased overall and indoor falls in 12 weeks in those aged 75 years and older in community-dwelling older adults. Language: en

This study aims to re-examine to what extent the testing procedure of the Artificial Athlete Berlin (DIN18032) is a valid evaluation method to assess the shock absorbency of third generation artificial turf (3-g turf) and to establish a new testing procedure, which precisely reflects the acute load by human sports action. The DIN test was conducted for 3-g turfs with different infill component. The baseline of the load of acute human sports action was obtained from the ground reaction force underneath the standard type of 3-g turf sample during landing from a 55-cm height with minimal shock attenuation. For reproducing the force similar to such a hard landing, a testing rig was developed and the same 3-g turf samples were tested. The DIN test failed to distinguish most types of 3-g turf and was found to be inappropriate to evaluate the shock absorbency of the 3-g turf mainly due to bouncing actions of the test foot on measured samples. In contrast, the newly developed testing rig succeeded in illustrating the differences of shock attenuation properties among most types of 3-g turfs in a high loading condition. In terms of players’ safety, the necessity of high loading test using an alternative testing procedure was highlighted.

Aim: To describe age- and sex-related differences in gait patterns of community-living men and women using 3-D gait analysis. Methods: Subjects (n = 2006) aged 40–84 years participated in the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA). Spatiotemporal components, including velocity, step length, step frequency, and double support time during a gait cycle, were calculated from 3-D coordinates and vertical force data. Velocity, step length and step frequency were normalized by leg length and acceleration due to gravity, and double support time was normalized to gait cycle duration. Results: Spatiotemporal walking variables of brisk velocity and step length were significantly greater in men than in women, while comfortable velocity and comfortable and brisk step frequencies and double support times were greater in women than in men. Age-related changes were marked at 70–84 years in most spatiotemporal variables in both sexes during comfortable walking. During brisk walking, age-related changes were observed from a younger age than during comfortable walking, and there were sex-related differences. Conclusion: The age-related gait alteration was obvious among those aged 70 years and older, and it accelerated markedly in women's brisk walking intensity. Geriatr Gerontol Int 2011; 11: 39–49.

Aim: The purpose of the present study is to assess the relationships of muscle strength and power with recent leisure-time physical activity and exercise during adolescence in middle-aged and elderly Japanese women. Methods: The subjects consisted of 1128 community-dwelling women aged 40–79 years. They were interviewed about their physical activity habits during leisure time in the past 12 months and exercise they engaged in during adolescence. Muscle function was measured as grip strength, knee extension strength and leg extension power. Subjects were grouped into three intensity levels for leisure-time physical activity and as to whether or not they engaged in adolescent exercise. The relationships of muscle strength and power with leisure-time physical activity and adolescent exercise were assessed using analysis of covariance controlled for age, smoking status, annual income and education level. Results: The proportion of subjects that participated in leisure-time physical activity was 67.1% (light, 33.7%; moderate or heavy, 33.4%). The subjects that engaged in adolescent exercise represented 41.9% of the total. There was a significant relationship between leisure-time physical activity and adolescent exercise. In the analysis of covariance controlled for age, smoking status, annual income and education level, leisure-time physical activity and adolescent exercise had significant main effects on all muscle strength and power measurements. However, there was no interaction effect between leisure-time physical activity and adolescent exercise. Conclusion: The results suggest that current leisure-time physical activity and adolescent exercise benefit muscle function in middle-aged and elderly women.

This study examined associations between physical activity and depressive symptoms in 1,151 community-dwelling adults in Japan. Physical activity was measured using a pedometer, whereas depressive symptoms were assessed with the Center for Epidemiological Studies-Depression Scale. A structural equation modeling with a cross-lagged panel design revealed that for the older adults (65-79 years of age), daily walking at baseline predicted fewer depressive symptoms at the 2-year follow-up, even after adjusting for confounders. In contrast, the association was not confirmed for the middle-aged adults (40-64 years of age). Findings suggest that age should be considered when estimating the effect of physical activity on psychological well-being.

To prevent a decline in gait with age, it is necessary to investigate age-related changes in gait performance and detect related factors. The purpose of this study was to assess the association between gait ability and leg extension power among middle-aged and elderly people. Height, weight, maximum gait velocity (MGV) and leg extension power (LEP) were measured in 752 males and females who participated in the National Institute for Longevity Sciences, Longitudinal Study of Aging (NILS-LSA). Age-related changes in MGV and LEP and the association between MGV and LEP were assessed. There were significant decline trends in height, weight, MGV and LEP with advancing age (p

We assessed longitudinal relationships between baseline testosterone and muscle mass changes in Japanese men. Data were collected from community-dwelling 957 adult men who participated in a longitudinal study of ageing biennially from 1997-2010. Appendicular muscle mass (AMM) was measured with dual-energy X-ray absorptiometry at baseline and follow-up examinations. The cut-off point of sarcopenia was defined as a skeletal muscle index (AMM/height(2))6.87 kg/m(2). Total testosterone (TT) and free testosterone (FT) were measured with a radioimmunoassay. The calculated FT (cFT) was determined with a formula using albumin, TT, and sex hormone-binding globulin levels. We analyzed 4,187 or 2,010 cumulative data points using generalized estimating equations. Low TT was not associated with sarcopenia. Low cFT (odds ratio = 2.14, 95% confidence interval: 1.06-4.33) and FT (odds ratio = 1.83, 95% confidence interval: 1.04-3.22) were associated with sarcopenia. Low FT may be a predictor of risk for muscle loss in Japanese men.

Brain atrophy is associated with impairment in cognitive function and learning function. The aim of this study was to determine whether daily physical activity prevents age-related brain atrophy progression.The participants were 381 men and 393 women who had participated in both the baseline and the follow-up surveys (mean duration = 8.2 yr). Magnetic resonance imaging of the frontal and temporal lobes was performed at the time of the baseline and follow-up surveys. The daily physical activities and total energy expenditures of the participants were recorded at baseline with uniaxial accelerometry sensors. Multiple logistic regression models were fit to determine the association between activity energy expenditure, number of steps, and total energy expenditure variables and frontal and temporal lobe atrophy progression while controlling for possible confounders.In male participants, the odds ratio of frontal lobe atrophy progression for the fifth quintile compared with the first quintile in activity energy expenditure was 3.408 (95% confidence interval = 1.205-9.643) and for the number of steps was 3.651 (95% confidence interval = 1.304-10.219). Men and women with low total energy expenditure were at risk for frontal lobe atrophy progression. There were no significant differences between temporal lobe atrophy progression and physical activity or total energy expenditure.The results indicate that physical activity and total energy expenditure are significant predictors of frontal lobe atrophy progression during an 8-yr period. Promoting participation in activities may be beneficial for attenuating age-related frontal lobe atrophy and for preventing dementia.

Need for inpatient care increases toward the end of life. We studied whether mobility limitation assessed approximately 5.8 years prior to death predicts the number of days in care during the last year of life. A population-based, prospective study with interviews conducted, on average, 5.8 years prior to death. Data on vital status and health care use were register-based. Participants consisted of 846 persons who had died between 1989 and 2004 at the age of 66–98 years. Participants were categorized as having mobility limitation if, at baseline, they reported difficulties in walking 2 km or climbing one flight of stairs. Mean ± standard deviation of age at death for men was 81.6 ± 6.2 years and the median number of days in inpatient care in the last year of life was 38.5 days. For women, the corresponding figures were 84.1 ± 6.1 years and 66.0 days. Only 11 % of men and 7 % of women had no inpatient care in the last year of life. The adjusted incidence rate ratio for all-cause inpatient care in the last year of life was 1.53 (95 % CI 1.09–2.16) among men with mobility limitation compared to those with intact mobility. Among women, mobility limitation did not increase the risk for all-cause inpatient care. Mobility limitation (vs. intact mobility) at 5.8 years prior to death markedly increases the need of inpatient care in the last year of life among men.

To describe age- and sex-related differences in gait patterns of community-living men and women using 3-D gait analysis.Subjects (n=2006) aged 40-84 years participated in the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA). Spatiotemporal components, including velocity, step length, step frequency, and double support time during a gait cycle, were calculated from 3-D coordinates and vertical force data. Velocity, step length and step frequency were normalized by leg length and acceleration due to gravity, and double support time was normalized to gait cycle duration.Spatiotemporal walking variables of brisk velocity and step length were significantly greater in men than in women, while comfortable velocity and comfortable and brisk step frequencies and double support times were greater in women than in men. Age-related changes were marked at 70-84 years in most spatiotemporal variables in both sexes during comfortable walking. During brisk walking, age-related changes were observed from a younger age than during comfortable walking, and there were sex-related differences.The age-related gait alteration was obvious among those aged 70 years and older, and it accelerated markedly in women's brisk walking intensity.

Detailed time-series of the resultant joint moments and segmental interactions during soccer instep kicking were compared between the preferred and non-preferred kicking leg. The kicking motions of both legs were captured for five highly skilled players using a three-dimensional cinematographic technique at 200 Hz. The resultant joint moment (muscle moment) and moment due to segmental interactions (interaction moment) were computed using a two-link kinetic chain model composed of the thigh and lower leg (including shank and foot). The mechanical functioning of the muscle and interaction moments during kicking were clearly illustrated. Significantly greater ball velocity (32.1 vs. 27.1 m . s(-1)), shank angular velocity (39.4 vs. 31.8 rad . s(-1)) and final foot velocity (22.7 vs. 19.6 m . s(-1)) were observed for the preferred leg. The preferred leg showed a significantly greater knee muscle moment (129.9 N . m) than the non-preferred leg (93.5 N . m), while no substantial differences were found for the interaction moment between the two legs (79.3 vs. 55.7 N . m). These results indicate that the highly skilled soccer players achieved a well-coordinated inter-segmental motion for both the preferred and non-preferred leg. The faster leg swing observed for the preferred leg was most likely the result of the larger muscle moment.

The purpose of the present study was to report the prevalence and circumstances of falls among community-dwelling elderly people in order to contribute to prevention of falls in the community. The subjects were 2,774 elderly people who participated in health examinations conducted by Tokoname-shi, Aichi Prefecture in 2002. The variables investigated in the present study were demography and history of falls in the past one-year. Circumstances of falls, e.g. time, location, activities associated with falls, cause of falls and degree of injury due to falls were asked when the subjects experienced a fall. The prevalence of falls among 2,774 subjects was 13.7%. It was significantly higher among women (17.2%) than men (8.3%, chi 2 = 48.1, p < 0.001). Prevalence increased as subjects get older. Circumstances of falls were assessed in 655 subjects. The distribution of time, location, activity associated with falls, cause and injury due to falls corresponded with previous fall studies among community dwelling elderly people. The incidence of falls was extremely high during the daytime and outdoors. Falls occurred most frequently while walking. The majority of falls were due to extrinsic factors. About 10% of all falls caused fracture.

INTRODUCTION The mechanical loads are an important factor to evoke bone formation, absorption of restraint, and structural strength. But, the bone remodeling is closely associated with bone absorption when mechanical loads are removed. Vogel, et al and Krolner, et al 1,2 suggest that bone loss occurs in individuals exposed to a reduced gravitational environment, as occurs in prolonged space flight and bedrest. Several recent reviews suggest that physical activity is beneficial to bone mass. Most studies, however, have not cleared on the quantification of mechanical loads acting on the lower limb during exercise trials. Above all, little is known about the effectiveness of the Ground Reaction Force (GRF) acting on the lower limb during gait in the middleaged and elderly. The purpose of the present study is to examine how mechanical loads acting on the lower limbs during gait affect Bone Mineral Density (BMD). METHODS The subjects in the study were the participants in the National Institute for Longevity Science-Longitudinal Study of Aging (NILS-LSA). The subjects were 1885 males and females who had measured BMD and GRF on gait protocol, aged 40-82 years in the second phase examination of the NILS-LSA. GRF signals were collected using two force plates with a sampling frequency of 240Hz (Kister, type9286, Swizerland). Then, peak GRF data were created from vertical component of GRF for the foot flat to heel off phase during stance phase of gait with custom-made program (Fig1). In this study, peak GRF accepted as an index of mechanical loads acting on the skeletal.