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Volume 30 (1981)
- Issue 6 Pages 277-
- Issue 5 Pages 231-
- Issue 4 Pages 183-
- Issue 3 Pages 131-
- Issue 2 Pages 73-
- Issue 1 Pages 1-
Volume 30, Issue 2
Displaying 1-6 of 6 articles from this issue
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SHIGEHIRO YOSHIZAWA, HIROKO HONDA, MAKOTO URUSHIBARA, NAKA NAKAMURA1981 Volume 30 Issue 2 Pages 73-85
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIn order to find out the criteria for the determination of maximal oxygen uptakes of very young children, five boys and five girls, aged four or five years, served as the subjects. They ran on the horizontal treadmill once a day for the constant three minutes on different days. The velocity was increased from the first 100m/min by 20m/min till the last where they could endure no longer for the three minutes. As the consequence, the velocities attained were 100m/min, 120m/min, 140m/min, 160m/min, 180m/min and 200m/min for boys and 100m/min, 120m/min, 140m/min, 160m/min and 180m/min for girls.
The expired airs were collected at rest and whole through the treadmill running.
Heart rates were also continuously registered not only at rest but also during the treadmill running.
The following results were obtained:
1) At the velocities of 100m/min, 120m/min and 140m/min apparent steady states of heart rates and Vo2 were established within the three miuntes both for boys and girls.
But boys showed lower heart rates and higher Vo2 during the steady states at a given velocity than girls did.
2) At the last velocity of 200m/min Vo2max were attained 30 seconds after the start of running for boys and also at the last of 180m/min girls reached Vo2max 60 seconds after the beginning.
It was, therefore, confirmed that if the work intensity was sufficiently high, Vo2 max could be reached at the latest between 30 and 60 seconds after the start of work for young children.
3) At the one step lower velocity than the last, namely, 180m/min for boys and 160m/min for girls, the plateaus of Vo2max were found for the last minute.
4) The heart rates simultaneously observed with Vo2max ranged from 202.4 to 206.4 bpm and also RQ were all above the unit. Accordingly these values could be regarded as the most important critieria for the evaluation of aerobic work capacity of young children.
5) When the velocity was high, the respiratory frequency sharply rises immediately after the start of running. For the first thirty seconds the breath rates reached 60 to 90/min.
6) If the duration of the running on the horizontal treadmill are constantly fixed three minutes, the upper limit of the velocity where the safe aerobic steady state can be established is 140m/min both for boys and girls.View full abstractDownload PDF (1282K) -
MASAHIRO KANEKO, TAKAFUMI FUCHIMOTO, HIDEKI TOJI, KENSAKU SUEI1981 Volume 30 Issue 2 Pages 86-93
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSThe effects of different intensities of muscle training on the force, velocity and power relationship have been examined on human elbow flexor muscles. Twenty male subjects, 18-22 years of age, were divided into 4 different groups ; G0, G30, G60, and G100. Their training loads were prescribed by a fraction of isometric strength (P0) measured at right angle of elbow joint : 0% P0 (G0 ; isotonic contraction without load), 30% P0 (G30), 60% P0 (G60), and 100% P0 (G100 ; isometric contraction) . The subject contracted his elbow flexors with maximum effort 10 times a day, 3 days a week for 12 weeks. The force-velocity relations and the resultant power output were determined, before and after training period, by a modified Wilkie's apparatus.
The training by maximum isotonic contraction without load (G0) was found to be most effective for improving maximum velocity (V0), while the isometric training improved isometric strength (P0) most. For this, the P-V relations of these groups were specifically modified by greater velocity component (G0) or greater force component (G100) . The G30 and G60 groups showed such all-round improvements that the P-V relations shifted in parallel with those of pre-training period. The maximum power (PVmax), which calculated from P-V relationship, increased most in G30, followed by G100, G60, and G0 groups.
From these results it was concluded that the different training loads brought about specific effects on P-V relation, and that the most effective load for improving maximum power was 30% of isometric strength.View full abstractDownload PDF (806K) -
KIYOJI TANAKA, YOSHIYUKI MATSUURA, TOSHIO MORITANI1981 Volume 30 Issue 2 Pages 94-102
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSVarious studies have reported on VO2max differences in men, with or without respect to distance run performances, and demonstrated that VO2max was the most important factor in endurance work capacity. This study was undertaken to reveal whether VO2max would still be the best determinant of endurance work capacity (or distance run performances), comparing it with AT parameters using the technique of correlational analyses. Twenty-seven distance runners, 16-26 years of age including an Olympic runner, underwent a multistage-incremental treadmill test for the assessment of submaximal and maximal work capacity. ATs were subjectively evaluated and determined as the point of breakaway of gas exchange criterion parameters according to Davis et al.'s method, and also referring to Wasserman et al.'s method.
The mean VO2max was 4.518 l/mmn (70.1 ml/kg⋅BW/min, 78.1 ml/kg . LBM/min), whilst the mean AT appeared to be 3.444 l/mmn (52.8 ml/kg/min, 75.60% of VO2max) . These results are in good agreement with previous results reported by others. Interestingly, all distance performances (i.e., 1-mile, 2-mile, and 3-mile) correlated highest with AT (ml/kg/min), secondly with exhaustion time, and thirdly with either VO2max or another AT parameter. AT (ml/kg/min) alone accounted for approximately 510, 73%, and 80% of the variance in the 1-mile, 2-mile, and 3-mile performances, respectively.
Since absolute VO2max is known to be a function of body size (e.g., body weight), an attempt was made to evaluate the relationships between the metabolic parameters and the distance performances through partial correlations holding the influence of body weight or LBM statistically constant. As a result, the correlation of VO2max (1/mm) with the 3-mile performance increased considerably to rp=-0.781 ; however, the degree of the relationship was not greater than the zero-order correlation (r=-0.896) obtained between AT (ml/kg/min) and the performance. Furthermore, when entered into a forward selection multiple regression with the 3-mile performance as the dependent variable, AT (l/min) accounted for only an additional 0.8% of the variance. VO2max (l/min), true % 02, % body fat body weight, VO2max (ml/kg/min), and vital capacity also accounted for only an additional 0.1%, 0.4%, 0.5%, 0.8%, 1.8%, and 1.8% of the variance, respectively. These data indicate that, considering the sample studied and limitations within this study, AT (ml/kg/min) could be the most significant determinant of the 3-mile run performance and, though to a lesser extent, the 2-mil eand 1-mile run performances.View full abstractDownload PDF (1080K) -
MITSUO NARUSAWA1981 Volume 30 Issue 2 Pages 103-113
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIt is said that number of muscle fibers does not change in the postnatal period. However, it has been reported that shortly after birth, the uni-motor neuron innervates may muscle fibers (Changeux) . Further it has been shown by Changeux that, during the growth of the immature muscle fiber, various neuromuscular junctions are developed. Also, as Rayne has pointed out, 50% of the total muscle fibers are developed within 6 weeks after birth. In addition it has been shown that during the aging process, the number of muscle fibers decreases.
This report, based on the aging phenomena of rats, discusses the change in the number of muscle fibers and the period of differentiation of muscle fiber type. Rats ware used from the one day of birth until the 540th day. Using an optical microgram, the total number of muscle fibers of both EDL and SOL muscle was counted. At the same time using the histochemical method, the differentiation of muscle fiber type was studied. The results are as follows : (1) Differentiation of muscle fiber type in both EDL and SOL muscle occurred within 3 weeks of birth. (2) 70% of the total muscle fibers in both EDL and SQL muscle developed from the first day to the 21st day after birth. (3) From the 21st day to the 105th day after birth, the number of muscle fibers decreased by 10%.
There are two possible reasons for the apparent increase in muscle fiber number. (1) Those immature muscle fibers not having sufficient sarcoplasma could not be detected and consequently couldn't be counted. (2) Satellite cells, which are thought to have a relation to myotube fusion, exist in large numbers even after birth and new muscle fibers may be frormed by myoblast fusion.
The decrease in the number of muscle fibers may occur as a function of the change from poly-innervation to uni-innervation. It is possible to think that as natural extinction takes place in the case of the former, some of the muscle fibers which were innervated in this manner also become extinct.View full abstractDownload PDF (10544K) -
MITSUTSUGU ONO, YOSHINORI MIYAZAKI, MASAYUKI WATANABE, HIDEKI HARA, KU ...1981 Volume 30 Issue 2 Pages 114-121
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSUninterrupted recordings of grip strength were measured in the male and female physical education students, university sports club members, middle-aged physical laborers and clerks, and young weight-lifters. The results were as follows ;
1) In the rate of supporting of uninterrupted measurements of grip strength, recordings among the males were greater than females. But, there were no differences between the recordings in the rate of supporting at morning and at evening.
2) In the university sports club members, the rate of supporting of Basketball club members were the most, Judo, the medium, Volleyball, Tennis, and others, the least.
3) Among the middle-aged subjects, the rate of supporting of uninterrupted measurements of grip strength indicate high in physical laborers and low in the clerks.
4) The rate of supporting of uninterrupted measurements of grip strength in youngweight-lifters was smaller than in well trained weight-lifters.
5) By the comparison between right and left recordings in the rate of supporting of uninterrupted measurements of grip strength, certain tendencies were observed in some sports, but, not greater than differences among some sports. Certain individual, however, indicate great differences between right and left recordings.
6) No significant correlations between maximum grip strength and rate of supporting of uninterrupted measurements were observed.View full abstractDownload PDF (773K) -
1981 Volume 30 Issue 2 Pages 122-129
Published: April 01, 1981
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (1023K)
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