The purpose of the present study is to observe the effect of aging on life fitness in Japanese. Life fitness consists of such parameters as body composition, joint torque (JT), leg extension power (LP) and run power (RP) . Subjects were 719 males and 859 females, from 20 to 80yrs old. The “aged” groups (over 70 years) indicated a higher percentage of body fat, compared to the younger groups. The subcutaneous fat thickness at the arms and legs measured by ultrasonography, was independent of age, while that at the abdomen and back was higher among aged groups. It is therefore considered that the higher percentage body fat observed in the aged groups is due mainly to accumulated subcutaneous fat at the abdomen and back. Muscle volume (MV) at the upper extremity indicated no significant difference among age groups; while that at the lower extremity (especially knee extensor muscle) was significantly lower in the aged groups compared to the younger groups. The ratio of JT to MV, considered as the index of specific tension, was lower for the aged groups than younger groups. Mechanical power performed during ergometer running and leg extension power were significantly lower for the aged groups. It is concluded that aged peoples due to low muscle volume of the knee extensor, experience deterioration in leg extension power, resulting in lower mechanical power for runnine.

The purpose of the present study is to investigate the influence of muscle cross-sectional area on maximal isometric strength (M. I. S.), and the influence of muscle fiber composition on the ratio of maximal isometric strength to muscle cross-sectional area in the leg extensor muscles.
Muscle biopsies were taken from the right vastus lateralis of 16 healthy untrained males. Cross-sectional area of the leg extensor muscles were measured by ultrasonic measurements. Maximal isometric strength were determined as peak torques using an isokinetic dynamometer.
Significant positive correlation was observed between muscle cross-sectional area and maximal isometric strength (r=0.61, p<0.05) . The ratio of maximal isometric strength to muscle cross-sectional area was 2.6±0.4 Nm/cm² (mean±S. D.) with a wide range of values from 2.0 to 3.3 Nm/cm². No relationship was observed to exist between the ratio of maximal isometric strength to muscle cross-sectional area and muscle fiber composition.
From these results it can be concluded that muscle cross-sectional area plays a more important role in producing a high maximal isometric strength than muscle fiber composition, and that the large variations observed in the ratio of maximal isometric strength to muscle cross-sectional area may be caused by factors other than muscle fiber composition.

The reliability of B-mode ultrasound for measuring subcutaneous fat thickness was evaluated in the cadaver. The ultrasonic device used in this study was the linear type employing a 5 MHz transducer. Ultrasonically determined-measurements of subcutaneous fat thickness was obtained on the upper arm, thigh, leg and abdomen. The border between subcutaneous fat and muscle tissues was able to be distinguish clearly by using this ultrasonic device. The subcutaneous fat thickness obtained ultrasonically were lower than those measured directly with using the slide calipers in the cadaver. Mean difference (standard deviation) between these values was 1.65 mm (0.98 mm) . A statistically significant correlation coefficient of 0.97 (p<0.001) and the linear regression equation of D=1.0963 B+0.9332 was observed between the subcutaneous fat thickness obtained from a B-mode ultrasonic (B) and direct (D) methods. The results suggest that B-mode ultrasonic device may be able to use for measuring subcutaneous fat thickness and a more reliable fat thickness may be able to obtain by revising the ultrasonically determined-measurements.

A study was carried out to investigate the distribution pattern of the subcutaneous fat on the whole body. Two helathy males, 31 and 38 years of age, participated as subjects in this study. Subcutaneous fat thickness measurements were made on the trunk, the upper and lower extremities, and the buttock with using B-mode ultrasonic device employing a 5 MHz transducer. The thicker subcutaneous fat were obtained on the portion near navel, outer sites of the lower trunk and the thigh just under the buttock for the both subjects. The thinner portions, on the other hand, were showed on the upper sites of the chest, forearm and leg. On the extremities, fat thickness was relatively remained constant over the whole sites compared with those on the trunk. These results suggest that the fat thickness distribution on the trunk is more significant than those on the extremities in males.

The pourpose of this study is to investigate the differences in muscle thickness between males and females of Japanese elite athletes. Subjects were 82 males and 65 females who were Japan candidates for the 1986 Asian and the 1988 Olympic Games 8 sports events, e, g., sprinters, middle and long distance runners, throwers, swimmers, gymnasts, volleyball players, basketball players, and oarsmen. Muscle thicknesses were measured by using B-scan ultrasound equipment with a 5 MHz transducer at the follwing sites: forearm anterior, biceps, triceps, subsucapular, abdomen, quadriceps, hamstrings and posterior calf. In results, comparison in muscle thickness between males and females were made at upper extremity (forearm+biceps+triceps), trunk (subsucapular+ abdomen) and lower extremity (quadriceps+hamstrings+calf) . Males showed siginificantly higher values in muscle thickness than females at all sites, except for trunk of distance runners and lower extremity of volleyball players. Relative values of females to males in muscle thickness were 59-84% for upper extremity, 68-89% for trunk, 84-94% for lower extremity. At upper extremity and trunk, Males indicated significantly higher values in muscle thickness per body height (muscle thickness/Ht) execpt for distance runners. At lower extremity, however, there were no siginificant differences in muscle thickness/Ht at lower between males and females except for gymnasts. Relative values of females to males in muscle thickness/Ht were 66-94% for upper extremity, 72-99% for trunk and 89-100% for lower extremity. Males showed significantly higher values in upper/lower extremity ratio of muscle thickness than females, except for sprinters and distance runners. On the other hand, females had significantly higher values in lower/trunk ratio of muscle thickness than males, except for distance runners and gymnasts. These results indicate that the differences in muscle thickness between males and females exist remarkably at upper extremity and trunk commpared to lower extremity. These anatomical differences in the degree of muscle development may be refered to genetic and/or enviromental factors.

This study aimed to estimate in vivo the compliance of tendon structure in human biceps brachii (BB) muscle for eight healthy male subjects. Elongation of the tendon of BB during isometric elbowflexion was directly measured by ultrasonography. Muscle force of BB (F_BB) was calculated from the elbow flexion torque and moment arm of elbow-flexor. When the EBB increased to 80%MVC (maximum voluntary contraction), the tendinous tissue of BB was elongated 10.24±2.52 mm, horizontally. The relationship between tendon length and F_BB was curvilinear and consisted of an initial region characterized by a large increase in tendon length with increasing F_BB under 50%MVC, immediately followed by a linear region. The compliance of tendinous tissues, estimated from the slope of the linear region, was 0.010±0.005 mm N, and did not show a significant correlation with MVC and muscle volume of the elbow flexors, estimated from muscle thickness. The compliance value observed here was lower than those of the medial gastrocnemius muscle and the tibialis anterior muscle, reported previously using the same ultrasonic method as the present study. This may be related to the functional differences among limb muscles in various human movements.

The purpose of the present study is to observe the accuracy of the ultrasonic A-mode method for measuring subcutaneous fat thickness. Nine healthy adults (4 males and 5 females) volunteered as experimental subjects. The skin and subcutaneous fat thickness at four different positions, the anterior, posterior, medialis and lateralis of the forearm, upper arm, leg and thigh, were measured by means of an A-mode ultrasonic subcutaneous fat caliper (CANON, CH 300-FT) and also by a B-mode method (ALOKA, SSD-120, ECHOVISION, Circular compound scanner) . Correlation coefficients of subcutaneous fat thickness between both ultrasonic methods were 0.808 for the forearm, 0.780 for the upper arm, 0.833 for the leg and 0.843 for the thigh with a statistical significance of 0.1 % level, respectively.
Differences of the thickness of subcutaneous fat between both methods were from 0.6 to 2.0mm as every absolute mean values. No significant differences were observed for mean subcutaneous fat thickness between both methods at each position. From these results, the A-mode ultrasonic method (CANON, CH 300-FT) is considered to be useful for measuring the thickness of skin and subcutaneous fat in human limbs.

The maximal isometric strength of the knee extension (KES) and cross-sectionl area of m. quadriceps femoris (MQF) were measured on 89 male Japanese elite athletes and 14 untrained men to evaluate the morphological and functional characteristics of athletes in the knee extensor muscles. Athletes were specialized in seven different sport events; 16 sumo wrestlers, 22 oarsmen, 8 volleyball players, 16 speed skaters, 12 association football plyers, 5 sprinters, 10 middle and long distance runners. KES was measured by using a specially designed straingages dynamometer at knee angle of 110 degrees (180 degrees= fully extended) . Cross-sectional area of MQF at the mid-thigh was determined by ultrasonic apparatus. The following results were obtained.
1. Sumo wrestters showed highest mean values (110.18 cm²) in MQF area among athlete groups. Lower mean values in MQF area were found in sprinters (86.34 cm²) and distance runners (73.86 cm²) whose values were not significantly different from that of untrained (75.32 cm²) .
2. In the cross-sectional area of each muscle bundle of MQF, sumo wrestlers, volleyball players and speed skaters showed higher mean values, and sprinters and distance runners had lower mean values as well as untrained men.
3. Higher mean values in percentage of MQF area to the total muscle area of thigh were observed in volleyball players (58.66%) and oarsmen (57.53%), lower mean value in association football players (53.81%), respectively. However, there were no significant differences in percentage of MQF area between untrained and each athlete group.
4. In the percentage of each muscle bundle area to MQF area, m. rectus femoris of association football players and m. vastus lateralis of speed skaters were significantly higher mean values compared with the untrained and other athlete groups.
5. KES were significantly related to the MQF area at 0.1% level (r=0.657) . There were significant relationships KES and each muscle bundle area in MQF area at 0.1% level. In the relationship between KES and each muscle bundle area, m. vastus lateralis showed the highest correlation coefficient (r=0.603) .
6. Association football players showed highest mean value (8.97 N/cm²) in KES per unit of MQF area among athlete groups. Its value was significantly higher than that of untrained men (8.06 N/cm²), distance runners (7.31 N/cm²), volleyball players (7.10N/cm²), and sumo wrestlers (7.50N/cm²) . There were no significant differences in KES per unit of MQF area intra athlete groups except for association football players.

Eleven feamle distance runners were assessed for body composition, limb composition, and skinfold thickness. Body composition was measured by underwater weighing method. The cross-sectional area of subcutaneous fat and muscle in forearm, upper arm, leg, and thigh were obtained by using ultrasonic system. Skinfold thicnesses of seven sites were determined with ultrasonic apparatus. Runners averaged 157.0 cm in body height, 50.2 kg in body weight, 18.9% in relative body fat, and 40.6 kg in lean body mass. When compared untrained normal women, runners had significantly lower relative fat. However, there were no significant differences in lean body mass between runners and untrained. Within runners the more successful performers possessed lower relative body fat. Runners showed lower values of skinfold thickness than that of untrained for all measurement sites. The greatest differences in skinfold thickness between runners and untrained was found in side abdomen. Subcutaneous fat area of runners were significantly smaller than that of untrained. However, runners showed significantly larger muscle area for leg only compared with untrained. These results in body and limb composition of female distance runners may be mainly reffered to the characteristics of aerobic running training.

The physiological cross-sectional area (PCSA) of knee extensors (KE) and flexors (KF) was determined using magnetic resonance imaging (MRI) in humans. Twenty two healthy male volunteers were assigned to the subjects and MRI was taken to obtained 41-52 consecutive axial images (slice thickness ; 10 mm, interslice gap ; 0 mm) from right-leg thigh. From these images, anatomical cross-sectional area (ACSA) of KE and KF was determined. Muscle volume was calculated from the summation of each ACSA and the distance between each section. Muscle length was determined as the distance from most proximal to most distal images in which the muscle visible. The PCSA of each muscle was calculated as muscle volume times the cosine of the angle of fiber pinnation divided by fiber length, where published fiber length : muscle length ratio were used to estimate fiber length. The isokinetic knee extension and flexion (angular velocity ; 30, 60, 180, 300, 450 deg/sec) was measured to estimate the muscle force at KE and KF. Specific tension of KE and KF was calculated muscle force deviled by PCSA. The mean muscle volume of KE and KF was 2178, 1141 cm³. The ratio of KE : KF was 2.6. The mean fiber length in KE was 7-8 cm, and in KF was 6-42 cm. Peak torque during knee extension was significantly higher than knee flexion at all angular velocities. The specific tension of KF was higher than that of KE at all tendon velocities. Moreover, relationships between specific tension and tendon velocity/fiber length, KF was still higher than that of KE. These results suggest that the capacity of tension development differ between KE and KF under the same shortening velocity per unit of sarcomere.