It has been reported that visceral fat (VF) is an independent predictor of the incidence for coronary heart disease, and is associated with its risk factors. The independent effects of exercise or dietary modification on VF remain to be fully elucidated, especially in obese middle-aged men. The purpose of this study was to investigate effects of exercise on VF compared to dietary modification. Thirty-five obese middle-aged men participated in this study. They consisted of exercise group (n=22, 51.4±11.6 yr, Group E) and diet group (n=13, 48.8±12.2 yr, Group D). Participants in Group E followed 90-min exercise sessions on a regular basis 3 days per week for 12 weeks. Participants in Group D attended weekly classes aimed at maintaining well-balanced 1,680 kcal/d diet for 12 weeks. Body weight decreased significantly in both groups (Group E : −2.9 kg, Group D : −5.4 kg). Visceral fat area (VFA) determined by computed tomography also decreased significantly (Group E : −32.0 cm², Group D : −39.4 cm²). An analysis of covariance adjusted by weight change revealed no significant group difference in VFA change. These results suggest that exercise-induced negative energy balance does not result in greater decrease in VFA as compared with dietary modification alone.

抄録全体を表示

Purpose : This study was to investigate the patterns of electromyography (EMG) amplitude responses during maximal, eccentric muscle action with shoulder adduction and diagonal movement, at 6 different positions on the dynamometer.
Methods : The participants for this investigation were 9 males and 5 females. Testing consisted of each subject performing eccentric muscle exercise of the dominant shoulder muscle at a velocity of 60°/sec and 180°/sec. Muscle activity values was recorded individually from six different muscles and peak torque values were extracted for each test from torque curves once. EMG data were normalized to the highest root mean square (RMS), and were expressed as a % maximum voluntary isometric contraction (%MVIC).
Results : The posterior parts of upper extremity muscle complex generate overall high muscle activity (> 40%MVIC) during all testing for eccentric muscle activity with diagonal shoulder movement. Posterior deltoid (PD), upper trapezius (UT), and middle trapezius (MT) muscles show differences between eccentric muscle action with shoulder adduction and eccentric muscle action with diagonal shoulder movement.
Conclusion : The present results show that an improved understanding of muscle activity patterns during different movement may benefit many fields of athletic trainers, coaches, and athletes, in addition to assisting in injury prevention for throwers, and even rehabilitation after injury.

抄録全体を表示

The objective of this study was to examine biological growth and development in skating performance by focusing on thigh muscle thickness and anaerobic power output capacity in Japanese speed skaters. One hundred thirty-three male and 96 female skaters aged from 10 to 22 years old were tested in this study. The anterior (MTA) and posterior (MTP) thicknesses of the thigh muscles were measured by the B-mode ultrasonic method. Maximal anaerobic power output capacity (MAP) was determined using a bicycle ergometer. The mean 500 m skating velocity (SV), calculated from recently attained individual best times, was used as a measure of skating performance. These parameters, along with height, were plotted on a logarithmic graph to obtain the allometric equation y=bx^a, where “a” is a growth index.
There were two sharp bends in the graph showing the relationships between MTA, MTP, MAP, SV and body height in both males and females. The growth indexes “a” between the first and second changing points in all the above relationships were observed to be larger than the other phases. Ranges of body height between the first and second changing point in muscle thicknesses (MTA, MTP) ranged from 152.2-154.8 cm to 168.1-168.3 cm in males, and from 142.8-144.9 cm to 154.4-157.6 cm in females. The ranges of MAP were from 139.8 cm to 166.8 cm in males, and from 138.8 cm to 157.8 cm in females. However, the height ranges of SV were from 147.4 cm to 167.8 cm in males, and from 142.2 cm to 153.2 cm in females.
From these results, it was suggested that accelerated development of skating performance and anaerobic power output capacity begins earlier than muscle structural development in speed skaters.

抄録全体を表示

The purpose of this study was to investigate sex differences in the muscle volume (MV) of the iliopsoas, psoas major, and iliacus muscles, normalized by fat free mass (FFM), in the elderly. The subjects were 15 males and 15 females 65 years of age or over. Serial transverse 1.5T magnetic images (10 mm slice) of each subject were taken between the 12^th thoracic vertebrae and the lesser trochanter. FFM was measured with a bioelectrical impedance analyzer. The mean MV of each muscle on the right and left sides were calculated and used for regression analysis of the relationship between MV and FFM.
A significant correlation was observed between MV and FFM of the iliacus in both sexes (p<0.01), but not between the MV and FFM of the psoas major. MV normalized by FFM and cross-sectional area (CSA) normalized by FFM^2/3 showed significantly greater values for the psoas major in the males than in the females (p<0.001), but there was no sex difference in the MV or CSA normalized by FFM of the iliacus.
These results suggest that elderly males tend to have a greater muscle volume and cross-sectional area of the iliopsoas than elderly females, and that these sex differences are attributable to differences in the psoas major.

抄録全体を表示

The magnitude of mechanical stress at the shoulder and elbow appears to be directly correlated with the degree of maximum shoulder external rotation (MER) during throwing. Therefore, it is very important to prevent excessive MER to minimize the risk of throwing injuries. The purpose of this study was to investigate the relationships between MER during throwing and the kinematic parameters of throwing mechanics, shoulder muscle strength, and shoulder range of motion in high school baseball players. The subjects were 40 male high school baseball players with no elbow or shoulder joint problems. Three-dimensional analysis was performed to calculate the MER angle. Then, the shoulder and elbow angles at initial foot contact (IFC) were computed. ROM and muscle strength of shoulder joint were also measured in each subject. Multiple linear regression analysis was used to relate the MER angle to these factors. Significant correlations were observed between the MER angle and the external rotation (ER) angle (r=−0.51, p<0.001) at IFC, and the ER range of motion (r=0.84, p<0.01). The MER angle significantly correlated with shoulder internal rotation (IR) at IFC. This finding suggests that stress on the shoulder and elbow could be increased by the degree of shoulder IR angle at the moment of IFC. Further, excessive ER range of motion may also be a risk factor.

抄録全体を表示

The purpose of this study was to examine the association between the pedometer-determined steps per day and physical fitness in order to evaluate the usefulness of the pedometer-determined physical activity to help individuals meet the recommended exercise target level of the Ministry of Health, Labour and Welfare (MHLW). The subjects consisted of 222 men and 172 women aged 71 years in community-dwelling elderly. The subjects wore a pedometer for 7 consecutive days to measure daily steps. The functional capacity was assessed based on the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) and self-reported performance of tasks (stair-climbing and chair-rising). Physical fitness tests included handgrip strength, knee extensor strength, leg extensor power, stepping, one-leg standing time with eyes open and maximal walking speed at 10 m. The men and women took on average 6,561±2,907 and 6,329±2,451 steps/day, respectively. Our subjects seemed to be highly functioning elderly, because the total scores of TMIG-IC (maximum : 13 scores) were on average 12 for men and women. The average of steps/day was significantly correlated with stair-climbing, chair-rising and knee extensor strength in men and women, and with body weight, body mass index (BMI), percent body fat (%Fat) and leg extensor power in women. The BMI and %Fat levels were significantly lower while the handgrip strength and knee extensor strength were significantly higher in women who attained to the level of the pedometer-determined physical activity as recommended by the MHLW.
The present study suggests that both men and women who take a lot of steps on a daily basis tend to demonstrate excellent leg strength and thus have a good ability to perform the tasks of daily living. In addition, the degree of obesity tends to be lower in women who regularly take a lot of steps. In addition, the number of daily steps taken has been recognized to be linked to gender, and such a link has also been suggested to be stronger in women than in men.

抄録全体を表示