In order to find the characteristics of physique and physical fitness of the field hockey players, data were collected from the Japanese Women's Team members in anthropometric measurements and physical fitness test over an eight-year period starting 1978.
From the data collected for this study the following observations were made :
1. From the data obtained during the last eight years, the tendency to increase or to improve was observed in the mean values of their physique and functional test items.
2. The Japanese National Women's hockey players were superior in agility, especially, side-step-test but inferior in muscular strength, flexibility and cardio-respiratory functions to national players in other activities ; their physique were smaller than others.
3. When compared with hockey players of foreign countries, it was observed that Japanese Women's hockey players were smaller in physique and inferior in muscular strength and cardio-respiratory functions.
4. When individual measurements of three years span were compared longitudinary, upper arm girth, muscular strength of upper limb and trunk had increased and jumping reaction time had improved, but not too many differences were observed in flexibility and cardio-respiratory function during the three years.

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This study was designed to investigate the change of postural control while repeatedly imposing the horizontal floor vibration in upright stance. A vibration table mounted with a force platform was vibrated sinusoidaly in anteroposterior direction under the condition of 2.5 cm amplitude and 0.5 Hz frequency. Ten female subjects, aged from 18 to 21 years, were equally divided into O-group and C-group. The subjects maintained the standing posture on the vibration table, for one minute with open and closed eyes in both groups in the first trial, for two minutes with open eyes in O-group and with closed eyes in C-group in the 2 nd to 11 th trials, and for one minute with closed eyes in O-group and open eyes in C-group in the 12th trial. The fluctuation of the center of foot pressure (CFP) in anteroposterior direction and EMGs of m. tibialis anterior and m. gastrocnemius were analyzed. The controllability of standing posture was evaluated by the mean speed of the CFP fluctuation. The muscle activity was examined with EMGs. The results were summarized as follows :
1) In a great number of subjects, the controllability of standing posture rapidly improved till the 3rd trial in each eye condition, while after the 3 rd trial changes of controllability were relatively small. Accordingly, it was suggested that by investigating the change of controllability for 5 trials, we could sufficiently detected an individual difference of the learning ability of postural control.
2) At the beginning of the practice, the controllability with open eyes was greatly superior to that with closed eyes. Although the difference of controllability between open and closed eyes decreased with advance of practice, in the 11 th trial that difference was obviously observed.
3) In a great number of subjects, the phase lag of the CFP fluctuation to the floor vibration increased till the 3rd trial according to improving controllability. In some subjects, the change of controllability was relatively small, the change of phase lag was small and also, correlations between the postural controllability and the phase lag weren't significant.
4) M. gastrocnemius was active when the CFP fluctuated forward and m. tibialis anterior when the CFP fluctuated backward greatly. In each eye condition, the magnitude of muscle activity decreased with practice and m. tibialis anterior was inactive in a great number of subjects in the last stage of the practice.
5) The controllability with open eyes didn't show a significant change after practice with closed eyes. By contrast, the controllability with closed eyes improved greatly after practice with open eyes and was approximately equal to that in the last stage of practice with closed eyes.

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97 baseball players from high school, universities and companies were subjected to this study in order to attempt to clarify the relationship between derangement of the elbow joint and lateral instabilitly by measuring various conventional parameters and the degree of lateral instability.
From the survey by questionnaire, 29 out of 97 players complained of elbow pain, paticularily on the medial side of the joint. The painful phases of the throwing motions were the acceleration phase (23 players, 61%) and release phase (7 players, 46%) . The hyperexten sion of the elbow on the dominant side was significantly smaller than that observed on the undominant side. X-ray examination revealed osteophyte formation at the tip of olecranon and medial joint space.
On the application of 63 kg⋅cm torque force, the varus deflection angle for the dominant side was 8.3° and that for the undominant side was 8.8°. The valgus angle for the dominant side was 12.2° and that for the undominant side was 10.8°. The varus stiffness (kg⋅cm/angle) was 9.5 for the dominant side and 8.4 for the undominant side. Valgus stiffness were 6.3 for the dominant side and 9.2 for the undominant side.
Thses results indicate that the lateral side become stiffer and medial side become looser in the dominant elbow than in the undominant one.
The unphysiological valgus stress at the acceleration phase would induce the osteophyte formation as well as the elongation of the medial collateral ligament on the medial side of the elbow. At the same time the impigement of the olecranon at follow through phase, would induce the osteophyte formation around the olecranon. Thses two factors would considerably influence the range of motion and the instability of the elbow joint.

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The purpose of present study was to investigate the relationship between the increase of sarcomere length, sarcomere number and tetanic tension of the extensor digitorum longus muscles during postnatal growth in mice. The following results were obtained ; 1) The cross-sectional area, length of muscle and fiber length increased rapidly up to 7th week. 2) The sarcomere number increased up to 9 th week, 3) The tetanic tension per cross-sectional area decreased significantly in 7 th week, 4) The maximum value of sarcomere length which was obtained at middle region of the fiber correlated significantly with the tetanic tension per cross-sectional area (the correlation coefficient : r=-0.675) . These observations suggest that the local expansion of sarcomere length during postnatal growth affects the tension development.

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The purpose of this study is to examine how the somatic-autonomic integration works in the motor learning. The coordinating tester was used to investigate changes in muscular activities, cardiac responses and respiratory responses.
1) The process of tracking diagrams by the coordinating tester was regarded as a motor learning from learning curves and the electromyogram (EMG) recorded from the acrominal part of m. deltoideus.
2) The sustaining bursts of EMG during exercise were observed in the first trial and the amplitude of EMG was more than 150μV.
3) The active period of EMG during exercise was not completely differentiated from the silent period in the 6 th and 26 th trials and the amplitude of EMG was 60 to 80 μV.
4) The active period of EMG during exercise was completely differentiated from the silent period in the 42 nd trial and the amplitude of EMG was 50 to 100μV.
5) The R-R interval of the electrocardiogram during rest fluctuated from 800 to 900 msec (67-75 beats/min) in subject F and during exercise approximately shortened to 550-600msec (100-108 beats/min) . As learning progressed, the cardiac acceleration was enhanced in the anticipatory and the initial phase of the exercise. It is considered that this conditional enhancement was established in feedforward control systems from the cortico-hypothalamic systems.
6) The R-R intervals during rest and exercise were shortened to about 700-800 msec (75-85 beats/min) in subject W in the first trial, which was taken as the oriental reflex. As learning progressed, changes of the R-R interval during rest (about 1, 000 msec, 60 beats/min) were differentiated from during exercise (about 600-700 msec, 85-100 beats/min) .
7) The respiratory rates during rest before exercise were 15 to 21 breaths/min and after exercise fluctuated from 12 to 36 breaths/min. Although the respiratory rates during exercise except for the first trial were 20-30 breaths/min, the rates in the first trial reached 30-36 breaths/min, which was also regarded as the oriental reflex.
As organization of the somatic nervous system produced the automatic muscle activities after motor learning, it is considered that actions of the automatic nervous system enhanced the anticipatory and initial cardiac accelerations to exercise.

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The purpose of the present study was to determine the effect of isometric strength training in prepubescent boys and girls on muscle strength and cross-sectional area of upper arm muscle. Subjects were ninety-nine healthy elementary school children from the 1 st, 3 rd and 5th grades and who were assigned to either training (TG, n=52) or control (CG, n=47) groups. The TG participated in a strength training program for 12 weeks which consisted of three maximaly sustained isometric contractions of elbow flexion for ten sec, twice a day, three days per week, whereas the CG did not participate in a special training program during this period. The cross-sectional areas of whole tissue, muscle, fat, and bone of the upper arm were measured by ultrasonic methods. Maximum isometric and isokinetic muscle strength of elbow flexion and extension were measured by means of a Cybex II. The hand-wrist X-ray photograph was used to estimate the skeletal age (TW 2 method) . Means (SDs) of skeletal age (yrs) were 6.27 (0.98), 8.48 (0.89), and 10.77 (1.22) for 1 st, 3 rd, and 5 th graders, respectively. After the 12-week training period, the cross-sectional area of the whole tissue increased significantly in both TG (8.9%, 2.52 cm²) and CG (7.3%, 2.11 cm²) . This interment in the TG was due to the significant increases in both muscle and bone areas, while that in CG was due to the significant increase only in fat area. Mean increase in muscle area in the TG was 10.3% (1.29 cm²) with this increase notable in 5th graders (12.5% for males and 12.7% for females) . The increment in cross-sectional area of muscle with training significantly correlated with the skeletal age (r=0.36, p<0.01) . Maximum isometric strength in the TG increased by 5.7% (0.3kg) in flexion and 17.5% (1.2 kg) in extension and in the CG, -0.3 kg (-1.0%) in flexion and 5.7% (0.3 kg) in extension. The increases in the strength of elbow extension were statistically significant in 1st (p<0.01), 3rd (p<0.05), and 5th (p<0.05) grade males. On the other hand, maximum isokinetic strength did not change with training. Muscle strength per cross-sectional area did not show a significant increase except in the training group of 5th grade boys. It was suggested that the effects of strength training on muscle area and strength for prepubescents were similar in its direction to but different in its magnitude from those found in adults.

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To investigate the relationship between maximal aerobic power (VO₂max) and fatigu-abililty during repeated isokinetic contractions, 39 male speed skaters (mean 20.8 years) served as subjects. They were divided into two groups according to their VO₂max levels ; high VO₂max group (HI, n=19) and low VO₂max group (LO, n=20) . VO₂max was measured in all subjects during incremental exercise on a bicycle ergometer and body composition was determined by densitometry. Cross-sectional area (CSA) of the leg extensor muscles was evaluated using ultrasonic method. Fatiguability was assessed during the fatigue test consisting of 50 repeated isokinetic knee-extensions at an angular velocity of 180 deg⋅sec^-1. Remark-able findings include :
1. There were no significant differences in body composition and thigh composition between the two groups except for high subcutaneous fat in group LO.
2. There were significant differences in VO₂max between group HI (3.93l⋅min^-1, 67.3 ml⋅kg LBM^-1⋅min^-1) and group LO (3.59l⋅min^-1, 59.9 ml⋅kg LBM^-1⋅min^-1) .
3. In the fatigue test, the average initial values did not differ, however, the average final values were higher in group HI. Also, a significant difference was observed in per unit CSA between the two groups.
4. Higher peak forces (kg) in group HI were observed after the initial 30 dymanic contractions per unit CSA and % of peak values (% peak force) .
5. A close relationship was demonstrated between VO₂max per LBM and the fatigue index, i. e., the mean decline in peak force with 50 contractions (r=-0.37, p<0.05) .
Based on the present findings it is suggested that maximal aerobic power (VO₂max) influences the rate of fatigue development even during short-term maximal isokinetic contractions, and that there may be some physiological cross-linkages between cardiopulmonary regulation and the metabolic properties of skeletal muscles. This finding is also in conformity with earlier results indicating the importance of oxygen delivery as a limiting factor for muscle performance.

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We investigated the effect of the difference of exercise intensity on the changes in ammonia and oxypurines (hypoxanthine·xanthine) . The subjects were 7 male university students who belonged to the Judo club. By using a bicycle ergometer with the same total work load (kpm), they performed following exercise : light exercise (27.1±0.8% HRmax), moderate exercise (72.6±2.5% HRmax) and exhaustive exercise. After light exercise, blood ammonia, serum oxypurines and urinary oxypurines excretion did not increase. Urinary uric acid excertion increased significantly, but serum uric acid decreased slightly. After moderate exercise, the significant increase was observed with blood ammonia (+ 35.3±5.9μmol/l) . Urinary oxypurines excretion also increased significantly, while serum oxypurines did not change. Also, serum uric acid rose slightly. After exhaustive exercise, the significant increase was observed with blood ammonia, serum oxypurines and serum uric acid. Each peak level and appearance time were +67.2±15.1μmol/l after 3 min, +31.4±7.6μmol/l after 30 min, 155.7±39.9μmol/l after 1 hr of exercise, respectively. These results suggest that AMP deamination occur during moderate intensity, while remarkable production of oxypurines which lead the increase of serum uric acid occur in higher exercise intensity.

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One male and eleven female subjects were examined in order to compare their ventilatory and heart rate responsiveness to hypoxia at rest and during moderate exercise (60 W) .
1) The slopes of the ventilatory response curve to hypoxia (AVE) were 306.5±229.5 and 1, 082.9±928.3l⋅min^-1⋅mmHg at rest and during exercise, respectively. Significant difference (p<0.05) between the two groups was found.
2) The slopes of the hypoxia-heart rate response curve (A_HR) were 704.9±477.3 and 1, 165.5±587.8 beats⋅min^-1⋅mmHg at rest and during exercise, respectively. The latter was significantly greater than the former (p<0.05) .
3) A significant relationship between AVE and AHR was observed (p<0.05) .
4) The relationship between ΔV_E50 and ΔHR₅₀, the increments of ventilation and heart rate from room-air to end-tidal Po₂ 50 mmHg, was also significant (p<0.01) .
These results indicate that hypoxic ventilatory and heart rate responsiveness during exercise is significantly greater than at rest, and point to the highly synergistic nature of the relationship between respiratory and cardiac regulations.

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The purpose of this study was to observe the effect of training on morphological properties in the collagen fibers of tendons. Wistar strain rats at 7 weeks old were assigned to high speed endurance (H), moderate speed endurance (M), jump training (J) and control (C) groups. The amount of exercise for H group (speed at 30m/min for 60 minutes) and M group (speed at 17m/min for 75 minutes) was equalized according to the amount of oxygen consumed during training. As for the anaerobic training (J group), rats made high jumping form the standing position, wearing jacket with 50% of body weight, 50 times/day, which lasted for 4-5 minutes. The training period was designed for 5 days per week for 16 weeks.
The follwing is a summary of the results obtained:
1) Increases in fiber areas of both Slow-Twitch (ST) and Fast-Twitch (FT) fibers were observed in the H, M and J groups. The ST fiber area of H group was significantly larger than that of C group. Significant increase in FT fiber area was observed in both M and J groups.
2) Hypertrophy of collagen fiber in gastrocnemius muscle tendon was observed in Hand M groups; especially, M group showed much larger increase than H group. It tended to be greater for J group as compared with C group.
3) Collagen fiber area and diameter of tendon in plantar muscle were slightly larger for H and M groups relative to C group, but these differences were not significant.
These results suggested that both types of aerobic training induced hypertrophy in the collagen fibers of the tendons and increased the tensile strength; especially, the group which trained longer hours induced the higher effect.

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