In order to establish a health promotion program for Taiyo Village in Ibaragi Prefecture, we initiated a research project at University of Tsukuba in 1996. The purpose of this research project are as follows : 1) Examine health promotion in the independent elderly, who make up the majority of the elderly population ; 2) Develop measures to prevent strokes, falls and fractures, which account for about half of the cases in which the elderly become bedridden ; 3) Establish a safe and effective exercise program according to scientifically proven health guidelines ; 4) Assess the efficacy of strength training, which has not been incorporated into most elderly exercise programs, in preventing the elderly from becoming bedridden due to falls and fractures ; 5) Develop a program that can be easily adapted by different municipalities ; and 6) Accumulate success stories at Taiyo Village and disseminate them throughout Japan. The results of this 7-year Taiyo Village project have yielded several important points: 1) Establishment of guidelines to improve life functions; 2) Development of an exercise program to improve and maintain functional ability for life ; and 3) Reduction in medical costs. The results of the present study suggest that when promoting the health of the elderly, it is important to not only study the efficacy of an exercise program, but to also establish a regional program that effectively utilizes research findings.

The purpose of this study was to examine the relationship between housebound (defined as elderly who go outside less than once a week) and physical fitness test (6 items of grip strength, situps, trunk flexion, foot balance, 10 m hurdle walk, 6 min walk), fitness test score, Tokyo Metropolitan Institute of Gerontology (TMIG) index of competence (3 factors of instrumental self-maintenance, intellectual activity, and social role), and General Health Questionnaire (GHQ) (4 categories of somatic symptoms, anxietynsomnia, social dysfunction, severe depression), considering the differences among gender and age.
The subjects were 296 community-dwelling elderly aged≥65 (mean age ; 75.5±4.9) . Of the subjects, 32% were male, and 57% were elderly aged≥75. Seventy-nine (27.2%) were housebound. The rate of housebound subjects with a full score for intellectual activity, social role on the TMIG sub-scales, 10m-hurdle walk and 6 minute walk was significantly worse than non-housebound subjects. The scores for social dysfunction and severe depression on the GHQ sub-scales for housebound were significantly higher than those for non-housebound ; and few housebound exercised more than 2 times per week or 30 minutes a day. The mental health of male housebound and housebound aged under 75 was the worst among all groups. On the other hand, female housebound and those aged≥75 had lower TMIG and physical fitness results. The characteristics of the housebound were different between genders. Among the housebound aged≥75, grip strength correlated with TMIG and GHQ-28 ; the 10 m hurdle walk correlated with severe depression, instrumental selfmaintenance and intellectual activity ; and the physical fitness score correlated with GHQ-28 after adjusted for age and gender.
Physical fitness correlated with TMIG and GHQ among the housebound; and few housebound exercised in daily life. Improving grip strength and walking ability may reduce the number of housebound.

It is well known that individual differences exist in exercise capacity or trainability. Several studies have shown that these individual differences are brought about by environmental effects such as life-style, diet and genetics. The potential of several specific genes to cause individual differences in endurance capacity or trainability has been investigated. The angiotensin-converting enzyme (ACE) gene, which has insertion (I) /deletion (D) polymorphism, is one of the most studied genes. Montgomery et al. reported that elite high-altitude mountaineers had higher I allele frequency of the ACE gene than did sedentary males. Moreover, they reported that subjects with II homozygotes showed higher trainability during a 10-week endurance training program than did individuals with ID heterozygotes or DD homozygotes. However, the results reported by Rankinen et al. did not support their results in terms of the relation between ACE genotype and cardiorespiratory endurance. Although numerous studies have reported a relationship between these two items, it remains controversial. Furthermore, mitochondrial DNA (mtDNA), the creative kinase and the Na⁺-K⁺-ATPase ∂2 genes have been studied as genes that may dictate individual differences in endurance capacity or trainability. We are going to report about the relation between these genes and exercise capacity and trainability.

Excess accumulation of visceral fat is reported to promote insulin resistance. However, it is not known whether or not insulin resistance improves without reducing visceral fat. Recent studies have reported, however, that exercise can improve insulin resistance. The aim of this study was to examine the effects of low-intensity exercise training on insulin resistance and visceral fat. Participants were 26 older adults, aged 63.9 ± 3.9 years, who were divided into two groups based on visceral fat area (VFA, cm²) measured by X-ray computed tomography. Eight men (153.4 ± 49.4 cm²) and 5 women (151.9 ± 45.5 cm²) were classified as having a VFA of 100 cm² or more (VFO group), and 6 men and 6 women as having less than 100 cm² (C group). After a 14-week exercise training program, VFA in women of the VFO group was significantly reduced (126.3 ± 40.0 cm²) ; though it did not reach 100 cm². However, homeostasis model assessment (HOMA-IR), an index of insulin resistance, significantly improved from 4.6 ± 1.9 to 2.2 ± 1.1 among women in the VFO group. These data suggest that improvements in insulin resistance for women with relatively high VFA are weakly associated with exercise-induced reductions in VFA. Based on these results, the activation of skeletal muscle with physical activity has the possibility of being independently associated with an improvement in insulin resistance without a significant decrease of VFA.

This study examined the effects of weight-bearing training on frail elderly whose level of care service is "care level 1" or "support required". Thirty-seven frail elderly (67-94 years old, mean age 82.8±6.8 years, men : N=8, 67-94 years, mean age 81.5±9.8 years, women : N=29, 69-92 years, mean age 83.1±5.8 years) participated in weight-bearing training including the use of a rubber band to improve physical function and lower limb muscle strength for eight weeks. Subjects were measured by a physical fitness test before and after the training. Ninety-two percent of the subjects completed the study. There was a significant improvement in knee extension maximum strength (1 RM)(p<0.01, n=32), functional reach (p<0.01, n=30), and sit-and-reach (p<0.01). There was a significant correlation between initial fitness level and improvement value (sit and reach : r=-0.362, p<0.05, n=33, functional reach : r=-0.563, p<0.01, n=31, stand up and sit down test : r=-0.729, p<0.01, n=31, stepping : r=-0.433, p<0.05, n=33, normal walking speed : r=-0.393, p<0.01, n=34). In conclusion, these results suggest that weight-bearing training may be a feasible and effective means of preventing muscle weakness and physical frailty for frail elderly. However, it is suggested that individual training programs need to be designed considering initial level of physical fitness.

A conducted to determine 1) the effect of high-velocity movement in resistance training with a constant load on the velocity of movement after training and 2) the differences in the effect on muscle hypertrophy according to training velocity. Fourteen of the total subjects (male; n=10, female ; n=7) were placed in the experimental group and agreed to participate in 8 weeks of training sessions (4 times a week) . Five of the 17 subjects were in control a group before the training session. Subjects performed elbow extension and flexion exercise using 50% of one repetition maximum (% 1 RM) load. The exercise session consisted of 6 sets of 10 repetitions and 30s of rest was taken between the sets. The subjects in the experimental group trained their arms using two different protocols ; one was high-velocity movement performed as rapidly as possible (Type R), the other was low-velocity movement performed at a constant and slow velocity (Type S) . Isokinetic torque in elbow flexion was measured at angular velocities of 60, 180, 300 deg/s, respectively, during elbow flexion performed under different constant loads of 0, 30, 50% 1 RM, and the muscle cross-sectional area (CSA) of the elbow flexor was determined before and after training. It was found that Type R did not increased isokinetic torque at 300 deg/s significantly after training. However, the increase in angular velocity of elbow flexion in Type R exercise tended to be higher than in Type S exercise. The increase in CSA [Type S; 11.2%, Type R ; 14.2%] was significantly higher in Type R exercise (p<0.05) . These results suggest that high-velocity movement with a constant load in resistance training might increase the angular velocity of movement in the same mode, but might not produce a change in isokinetic strength, which involves a different mode of muscle contraction. Muscle hypertrophy would be induced to a greater extent by high-velocity movement than by low-velocity movement in resistance training with a constant load.

This study aimed to investigate the influence of aging on muscle thickness in lower limbs, with specific emphasis on the site- and gender-related differences. Subjects were a total of 191 healthy young and elderly persons of both genders : 51 young men (24.2±3.6 yrs), 45 young women (23.1±3.2yrs), 51 elderly males, and 44 elderly females. Lower leg anterior, and lower leg posterior muscle thickness was determined using a brightness mode ultrasonographic apparatus. At all sites except for the thigh posterior, the muscle thickness values were significantly greater in the young than in the elderly groups of both genders, even in terms of the ratio of muscle thickness to body mass^1/3 (Mt/Wt^1/3 ratio), calculated to normalize the morphological differences. The relative difference in muscle thickness between the two age groups was the greatest at the thigh anterior and the least at the thigh posterior in both genders. Between young men and women, the men showed significantly greater muscle thickness and Mt/Wt^1/3 ratio at every site than the women. Between the elderly groups, however, Mt/Wt^1/3 ratios at all sites, except for the thigh anterior, did not show significant gender-related differences. Relative differences in both muscle thickness and Mt/Wt^1/3 ratio between the young men and women were similar among the sites, but between the elderly groups the corresponding values at the thigh anterior were greater than at the other sites. These results indicate that 1) the influence of aging on muscle thickness differs between the muscle groups located in the anterior and posterior sited within the same segment, 2) for women, the age-related loss of muscle thickness at the thigh anterior is relatively greater as compared to those at the other sites of the lower limb.

The influences of age on muscle architectural characteristics, i. e., muscle thickness, pennation angle, fascicle length, were studied in 121 men and 229 women aged 17 to 85 yrs. The subjects were divided into three age groups (younger : 17-39 yrs, middle-aged : 40-59 yrs, elderly : 60-85 yrs) for both genders. Muscle thickness and pennation angle of the vastus lateralis (VL), medial gastrocnemius (MG), and long head of triceps brachii (TB) muscles were measured using B-mode ultraso-nography, and fascicle length was estimated. In all age groups, men had significantly greater relative muscle thickness (to limb length) in VI, and TB than women, but not in MG. Relative muscle thickness of VL was significantly lower in elderly than in younger and middle-aged subjects. Ilowever, the corresponding differences in MG and TB were insignificant. The pennation angle of VL was significantly lower in elderly than in younger and middle-aged subjects, although there were no significant differences in pennation angles of MG and TB among the three groups. These results suggest that the decrease in thickness of vastus lateralis muscle with aging is significant, but not significant for medial gastrocnemius and triceps hrachii muscles.

The ability to walk is just as important for the elderly as it is for young people. In fact, in the elderly, decreased mobility limits function in daily life and can lead to more serious situations (e.g., becoming bedridden) . The elderly population has increased over the last decade, and many researchers have studied the mobility of the elderly. However, the focus of most studies has been to facilitate recovery of bedridden individuals and prevent the elderly from becoming bedridden, and particularly to prevent fall-induced fractures, which often cause the elderly to become bedridden. However, about 70-80% of the elderly population do not require care, and it is necessary to conduct research on the maintenance of activities of daily living to make it possible for the elderly to work or volunteer. From this perspective, mobility is an important physical factor. Mobility is dependent on muscle activity and it has long been known that aging reduces muscle mass. Therefore, it is feasible to assume that reduced muscle mass leads to decreased ability to walk, and we have proven that there is a close correlation between the two. When presenting the idea of strength training to the elderly, it is appropriate to focus on the maintenance and improvement of mobility, not on the training itself. The results of our research can be summarized as follows:
Muscle mass decreases with age, with the legs being affected to a greater degree than the arms. Moreover, muscle atrophy is dependent on weakening of muscle fibers, especially fast-twitch (Type II) fibers. Reduced lower limb muscle mass increases the risk of falling and can decrease walking ability to a degree that can affect daily living activities.
In order to improve reduced muscle mass in aging, it is important to use an exercise program that is designed to strengthen fast-twitch fibers, which can be followed even by the elderly. Since walking therapy mostly mobilizes slow twitch fibers, it is not effective in preventing and improving muscle atrophy. It is important to have an exercise program that is designed to mobilize fast-twitch fibers.

Walking is the most basic movement in daily life, and is a popular exercise for eloerly individuals to keep their health. However, it is not clear how walking is effective in keeping or increasing the muscle mass and bone intensity of the lower limbs. This study aimed to investigate the relationships between walking steps per day during daily life and either the muscle thickness values of lower leg anterior and posterior or the bone intensity of calcaneus. The subjects were 116 healthy men (n=31) and women (n=85) aged from 60 to 78 yrs, Walking steps per day were deter-mined using a pedometer. Muscle thickness values at the lower leg anterior and posterior sites and the osteo sono assessment index (OSI) of calcaneus were determined using ultrasonographic apparatuses. In women, OSI correlated significantly with walking steps (r=0.265, p<0.05) and the product of walking steps and weight (r=0.369, p<0.05) . In both genders, however, no significant correlations were found between walking steps and muscle thickness values at the two sites. The findings here suggest that increasing the number of walking steps during daily life will improve the intensity of calcaneus for elderly women, but is not effective for inducing hypertrophic change in the muscles located in the lower limbs for elderly individuals of both genders.