Journal of Physiological Anthropology最新文献

The purpose of this study was to clarify the fall risk characteristics of the elderly participating in an exercise class. The subjects were comprised of 206 elderly Japanese aged 60 or older (37 males, 169 females) who participated in an exercise class, approved by the local government, once a week for 6 months. Physical fitness and ADL capability were evaluated by the physical fitness test of the Ministry of Education, Culture, Sports, Science and Technology. Fall risk was evaluated using the Fall Assessment Chart. Subjects were divided into two groups, high fall risk (total fall risk score > or =5) and low fall risk (total fall risk score <5), and the percentage of subjects in the high risk group was calculated. The percentage of subjects with a high fall risk was 15.8%, lower than the documented rate of the community-dwelling elderly in a previous study. Significant differences between fall risk groups were found in balance and ADL capabilities of walking, holding and changing posture and muscular strength. These functions also were significantly related to fall risk elements such as fall anxiety and slipping or stumbling at home in the partial correlation analyses. Improvement of these functions during exercise class may be useful in decreasing fall risk in the elderly.

Deep squatting places a burden on the lower limb muscles and influences postural balance. We attempted to determine the effects of postural changes on the rectus femoris, tibialis anterior, gastrocnemius, soleus, and extensor digitorum brevis muscles during squatting in 8 healthy male subjects. Three squatting conditions were involved: full squatting (FS), tiptoe squatting (TT), and tiptoe squatting on a 15 degrees slope (TTS), performed randomly and recorded in a period of 4 min for each task. The influence of the squatting condition on electromyography and vertical ground reaction force parameters was examined in order to observe the effect of postural alteration on muscle activity and balance control. The results showed that the change of squatting posture from FS to TT decreased the activity of the rectus femoris and tibialis anterior muscles. FS has been suspected as a main cause of musculoskeletal complaint during prolonged squatting. In contrast, as the heel was lifted, the extensor digitorum brevis muscle increased to 39% of maximum activation. On the other hand, sway analysis at TT showed balance instability regarding the large area occupation of the center of pressure displacement. The presence of a 15 degrees slope significantly reduced the muscular load. This simple study suggests that the inclusion of a sloping surface in daily activities that requires a squatting posture would be an effective means to reduce muscular load.

Testosterone and estradiol levels were measured by saliva assays in 15 young men, and their relationships with different processes in a mental rotation task were elucidated. The estradiol level was positively correlated with reaction time; this effect was yielded by the slope of functions relating performance to angular disparity. These findings suggest that estrogen may inhibit the performance of a mental rotation task by affecting perception of the rotation process.

This study determined the physical fitness component that contributes to improving and maintaining health status for each age group as well as quantifying the degree of the relationship between health status and physical fitness in middle-aged and elderly females. The participants were 2,371 females aged 30 to 69 years. Ten physical fitness tests and medical checkups were performed. The participants were divided into a healthy group and an unhealthy group according to health status. Multiple discriminant analysis was applied to the multivariate data. Correct discriminant probabilities of the multiple discriminant function to discriminate the healthy and unhealthy groups for females ranged from 63.0% to 77.5%. These results suggest that there is a relatively high relationship between health status and physical fitness level for middle-aged and elderly females. With each individual's discriminant score calculated by the obtained multiple discriminant function as the index of the degree of health, the Pearson's correlation coefficient of the discriminant score and the performance in each physical fitness test were calculated. The aging change from 30 to 69 years old was classified into four patterns according to the contribution. The result of this study is considered to be useful as objective data to prepare an exercise program considering the contribution of the physical fitness component of health status.

This study sought to determine the characteristics of gait patterns and muscle activity in the lower extremities of elderly women during underwater treadmill walking against water flow. Eight female subjects (61.4+/-3.9 y) performed underwater and land treadmill walking at varying exercise intensities and velocities. During underwater walking (water level at the xiphoid process) using the Flowmill, which has a treadmill at the base of a water flume, the simultaneous belt and water flow velocities were set to 20, 30 and 4 m.min(-1). Land walking velocities were set to 40, 60 and 80 m.min(-1). Oxygen uptake and heart rate were measured during both walking exercises. Maximum and minimum knee joint angles, and mean angular velocities of knee extension and knee flexion in the swing phase were calculated using two-dimensional motion analysis. Electromyograms were recorded using bipolar surface electrodes for five muscles: the tibialis anterior (TA), medial gastrocnemius (MG), vastus medialis (VM), rectus femoris (RF) and biceps femoris (BF). At the same exercise intensity level, cadence was almost half that on land. Step length did not differ significantly because velocity was halved. Compared to land walking, the maximum and minimum knee joint angles were significantly smaller and the mean angular velocity of knee extension was significantly lower. Knee extension in the swing phase was limited by water resistance. While the muscle activity levels of TA, VM and BF were almost the same as during land walking, those of MG and RF were lower. At the same velocity, exercise intensity was significantly higher than during land walking, cadence was significantly lower, and step length significantly larger. The knee joint showed significantly smaller maximum and minimum angles, and the mean angular velocity of knee flexion was significantly larger. The muscle activity levels of TA, VM, and BF increased significantly in comparison with land walking, although those of MG and RF did not significantly differ. Given our findings, it appears that buoyancy, lower cadence, and a moving floor influenced the muscle activity level of MG and RF at the same exercise intensity level and at the same velocity. These results show promise of becoming the basic data of choice for underwater walking exercise prescription.

This study aimed to examine the reliability and sex- and age-related differences of step tests with stipulated tempos as well as to clarify useful test parameters and tempos. One hundred forty elderly people and fifty young adults conducted tapping and stepping tests, matching the tempo provided by a metronome. Both tests involve movements where the subject touches a sheet with both the right and left hands or right and left legs at a designated spot. Evaluation parameters were the time difference between the beep sound and the time at which the sheet was touched in both tests as well as two-leg support and one-leg support times in the step test. The trial-to-trial reliability of the parameters in both tests was high. The time differences of both 40 bpm tests in the elderly were larger in males than in females. In the step test, the time difference and two-leg support times of the elderly were larger, in the order of 40, 60, and 120 bpm, and the one-leg support time was less in 40 bpm than 60 bpm or 120 bpm. The one-leg support time of the young subjects was larger, in the order of 40, 60, and 120 bpm. A significant age-related difference was found in the 40 bpm and 60 bpm test, and the time difference and two-leg support time were larger in the elderly while the one-leg support time was larger in the young subjects. The time difference at 40 bpm in the elderly was larger in the step test than in the tap test. There was no significant difference between both tests in the young subjects. In conclusion, the step test with the slow tempo, because it requires a long one-leg support phase, is effective for evaluating dynamic balance in the elderly. The time difference and two-leg and one-leg support times are effective evaluation parameters of the step test.

This study aims at examining the reduction of indoor air contaminants by plants placed in an indoor space. Field measurements were performed using Aglaonema brevispathum, Pachira aquatica, and Ficus benjamiana, which were verified as air-purifying plants by NASA. Three conditions for the amount of plants and positions were used in two separate rooms whose dimensions are identical. The concentration of Volatile Organic Compounds (VOCs) was monitored three hours after the plants were placed and three days after the plants were placed. The variations of concentration of Benzene, Toluene, Etylbenzene, and Xylene (BTEX), as well as Formaldehyde, which are all known as the major elements of Volatile Organic Compounds were monitored. The amount of reduction in concentration of Toluene and Formaldehyde was monitored 3 hours and 3 days after the plants were placed in the space. The reduction in the concentration of Benzene, Toluene, Etylbenzene, Xylene, and Formaldehyde was significantly greater when plants were present. When plants were placed near a window, the reduction of concentration was greater. The more plants were used, the more a reduction of indoor air contaminants occurred. The effect of reducing the concentration of air contaminants increased when the amount of plants increased, and when the plants were placed in sunny area. The concentration of Toluene was reduced by 45.6 microg/m(3) when 10% of the model space was occupied by Aglaonema brevispathum.

The effect of aging on muscular power development was investigated by determining the force-velocity relationship. The muscle cross-sectional area (CSA) was estimated by the thickness of the elbow flexors. The subjects were 19 elderly males aged 69.1+/-3.7 years old (G-70 group), 15 middle-aged males aged 50.9+/-3.5 years old (G-50), and 19 young males aged 21.2+/-1.3 years old (G-20). The G-70 group had the slowest shortening velocities under various load conditions, resulting in the lowest force-velocity relationship. The maximum values for force (Fmax), velocity (Vmax), power (Pmax), dynamic constants (a, b), and the a/Fmax ratio were determined using Hill's equation. The a/Fmax ratio determines the degree of concavity in the force-velocity curve. The a/Fmax ratio was greatest in G-70, followed by those in G-50 and G-20, while the maximum values for force (Fmax), velocity (Vmax), and power (Pmax) were significantly lower in G-70 than in the other groups. Fmax and Pmax per CSA were lowest in G-70, and Vmax per unit muscle length was also lowest in G-70 as compared to the other age groups. The ratio of G-70/G-20 was greatest in Pmax (69.6%), followed by Fmax (75.3%) and Vmax (83.4%). However, there were no significant differences in CSA among the 3 age groups. Our findings suggest that muscle force and shortening velocity may decline gradually in the process of aging attributed to declining muscle function rather than CSA.

This study attempts to clarify whether intensity of exercise influences functional sympatholysis during mild rhythmic handgrip exercise (RHG). We measured muscle oxygenation in both exercising and non-exercising muscle in the same arm in 11 subjects using near infrared spectroscopy (NIRS), heart rate, and blood pressure. We used the total labile signal to assess the relative muscle oxygenation by occlusion for 6 min. Subjects performed RHG (20 times/min) for 6 min at 10%, 20%, and 30% of maximal voluntary contraction (MVC) at random. We used a non-hypotensive lower body negative pressure (LBNP) of 220 mmHg for 2 min to elicit reproducible enhancement in muscle sympathetic nerve activity (MSNA) at rest and during RHG. LBNP caused decreases of 16.4% and 17.7% of the level of muscle oxygenation at rest (pre) in exercising (forearm) and non-exercising (upper arm) muscle respectively. Muscle oxygenation in non-exercising muscle with the application of LBNP during RHG did not change significantly at each intensity. In contrast, the decrease in muscle oxygenation in exercising muscle attenuated progressively as exercise intensity increased (10% MVC 8.8+/-2.8%, 20% MVC 7.1+/-2.0%, 30% MVC 4.6+/-3.0%), when LBNP was applied during RHG. The attenuation of the decrease in muscle oxygenation due to LBNP during RHG at 10%, 20%, and 30% was significantly different from that at rest (p<0.01). These findings indicate that functional sympatholysis during mild RHG might be attributed to exercise intensity.