The study aimed to examine age group and individual differences of the controlled force exertion by the sinusoidal and quasi-random waveforms. A total of 180 male adults who were right-handed and aged 20 to 86 years (Age 45.8±18.6 yrs) matched their submaximal grip strength to changing demand values, displayed as either a sinusoidal or a quasi-random waveform appearing on the display of a personal computer. The quasi-random waveform was changed by π radian with amplitude and in π/2 radian with frequency (peak and mean frequency were 0.1 Hz in both waveforms). The subjects performed both the controlled force exertion test for 3 trials with 1-min intervals (one trial was 40 sec), after one practice trial using the dominant hand. The measurement order was randomly assigned. A total of the differences between the demand value and the grip exertion value for 25 sec was used as an evaluation parameter. The measurements showed a constant tendency to increase with age group in both waveforms. Significant linear regressions were identified (r2SW=0.83, r2RW=0.89), but there was no significant difference in the rate of increase of both waveforms. The result of the analysis of variance showed insignificant differences among means of both waveforms, except for those after 70 years of age, and the differences between means in ages greater than 50 years and 20 years enlarged in both waveforms. Individual differences were almost the same in both waveforms (CVSW=24.1〜42.1, CVRW=22.9〜41.8). The performance of the controlled force exertion test tended to decrease with age in both the sinusoidal and quasi-random waveforms, and their rates of decrease are remarkable after 50 years of age. The change of individual differences with age is almost the same in both waveforms.
This study aimed to examine gender and age differences in the contact area of the soles of the feet and its relationship with physique in 170 healthy preschool children aged 3 to 6 years. They stood on the instrument (Pedoscope) with their bare feet in a standing posture, while closely gazing at a fixed object located 2 meters in front of them. During standing, the contact surface area of the soles of their feet was pictured and recorded. Gross foot length, foot length (the length taken the toe length from the gross foot length), gross foot area, foot area (the area taken the toe area from the gross foot area), and the upper part of the foot width grow with age and have close relationships with growth of height and weight. However, each toe area and toe length hardly grow. The upper part of the foot width grows with age and the contact area of the soles of the feet changes into the form of an inverted trapezoid with high stability. Gross foot area, foot area, and the middle part of the foot width are larger in boys than in girls, but the difference is not large.
Definite findings as to the seasonal variation in height among preschool children have not been reported. Therefore, the present study was to verify the relationship between seasonal variation and monthly pattern of growth in height based on analyzing age (month) at LPV (Local Peak Velocity) detected on the velocity curve of the monthly pattern of growth by applying the wavelet interpolation method (WIM) to the monthly pattern of growth in the height of preschool children. The WIM was applied to the longitudinal monthly pattern of growth in height for one year in seventy-five year-old boys and sixty-eight five year-old girls. The obtained monthly pattern of growth distance curve was then differentiated, and the LPVs were detected from the derived velocity curve. The appearance pattern of LPV detected for one year, age (month) at LPV and at maximum LPV were analyzed. As a result, the appearance pattern of LPV often appears in three places and four places in boys and girls. The appearance time of LPV was around May, July-August and December in boys and girls. The appearance time of maximum LPV was around May and July-August. Therefore, though the promotion of growth was shown in summer as a seasonal variation of height, on the other hand, the inherited monthly pattern of growth in height was estimated. However, it is difficult to judge whether the pattern is of a seasonal variation or inherited growth.
We evaluated the effects of a 3-month exercise program in reducing risk factors of falls in determined care level of assistance required under the long-term care insurance program. A pamphlet containing information on “Fall Prevention Exercise Classes” was mailed to 185 potential participants with assistance required. Thirty five agreed to join the exercise classes. For a 12-week intervention period, participants received exercise program twice a week focused on improving muscle strength, balance, and walking ability. Outcome measures included physical fitness, Tokyo Metropolitan Institute of Gerontology (TMIG) index score, and fear of falling. The research protocol was approved by the institutional review board of TMIG, and informed consent was obtained from each participant. Of participants, 65% perceived that they were able to walk stably, and 60.0% were confident that they were able to prevent falling by themselves. The maximum walking speed increased significantly from 1.14±0.46 m/s at baseline to 1.39±0.47 m/s after intervention (improved 21.4%, P<0.001), and knee extension power increased from 17.67±6.01 kg at baseline to 23.57±8.49 kg after 3-month exercise program (increased 33.4％, P<0.001). The percentage of fear of falling was significantly decreased from 90.5% before intervention to 61.9% after 3-month exercise (P=0.031). These results suggest that exercise program targeting modifiable muscle strength, balance, and walking ability is a safe and effective intervention to reduce the risk factors of falls, and fear of falling in frail elderly.
In this study an attempt was made to demonstrate the changes in height growth in two recent periods of the Mongols, one of the ethnic groups in China, by comparing the height growth in adolescence in this group in the years 1985 and 2005. Nearly all previous analyses have used growth distance curves, with analysis of the velocity curve based on the difference value in the amount of annual growth. This method may show that young people are becoming larger, but there is no guarantee that this method objectively demonstrates early maturation. The present study applied the wavelet interpolation method proposed by Fujii (2006), and specified the age of maximum peak velocity (MPV) in growth during puberty from the height growth velocity curve. Then, based on age at MPV and annual changes in MPV, early maturation in height growth and time changes in the velocity curve in Chinese Mongols was demonstrated. The data used were height data for Mongols and Han Chinese (boys and girls 7–18 years of age) in the Inner Mongolia Autonomous Region, extracted from national surveys of student physique and health in China conducted in the years 1985 and 2005. The data used for Japan were growth data from the Survey of Physical Strength and Athletic Ability conducted by the Ministry of Education, Culture, Sports, Science and Technology in the years 1985 and 2005.
The results did not reveal any marked changes in the growth of Japanese boys and girls between these two periods. However, a tendency for earlier age at MPV was seen in both boys and girls in Han and Mongol Chinese. This tendency was particularly marked in Mongols, and maturity was clearly earlier. The trend in these recent 20 years from 1985 to 2005 in Inner Mongolia is thought to be similar to the past phenomenon of earlier maturation in Japanese that was influenced by high socioeconomic growth. The factors for the change seen in Mongols are assumed to be considerable improvements in recent years in the dietary habits and environment of Mongols in the Inner Mongolia Autonomous Region of China, and improvements in their social and economic environment.
This study aimed to examine mental toughness related to the competitive performances of water polo players from the viewpoints of competitive levels,player position and years of competitive experience and to propose an evaluation criterion.A survey composed of 51 items representing 15 mental toughness factors was administered to water polo players, and the data from 412 male respondents (age:17.8±3.8yr,years of competitive experience:3.8±2.6yr) with valid responses were analyzed.Significant differences were found in forecasting-discretion ability, decision, confidence, imaging and in the total score between two groups with different years of competitive experiences.The group with more experience(over 7 years) had higher scores in the above factors. There was no significant difference between groups differing in competitive level or player position.In addition,distribution of all mental toughness factors and the total score followed a normal distribution.Based on these data,we proposed an evaluation criterion based on a 5-point rating for each mental toughness factor.
To investigate the tendency of change of Bone mineral density (BMD) with age is important to seek Peak bone mass. Many cross-sectional studies have been carried out examining the change of BMD with age. Few cross-sectional studies were reported statistically the tendency of change of BMD with age. We applied speed of sound (SOS) for indicator to examine BMD. In this study, we measured SOS in 145 healthy Japanese women aged 20-49. We examined the tendency of change of SOS with age based on least square approximation polynomial. To determine the best least square approximation polynomial, we compared each coefficients of determination and sum of residual square. Finally the best least square approximation polynomial was cubic least square approximation polynomial. We proposed the standard change chart of SOS value with age based on the cubic least square approximation polynomial. In future studies, examining the change of SOS with age based on more data is needed because of the reliability.