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Volume 26 (1977)
- Issue 4 Pages 159-
- Issue 3 Pages 103-
- Issue 2 Pages 59-
- Issue 1 Pages 1-
Volume 26, Issue 2
Displaying 1-6 of 6 articles from this issue
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SHIGERU MORIMOTO, TOSHIO OHMORI, HIDESHI HASEGAWA, HIROSHI KURATA, MAK ...1977 Volume 26 Issue 2 Pages 59-63
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIt had been proposed by Kurata that relative threshold value Fth of single motor units depends on the gradient G (kg/sec) of the tension increase of muscle in such a manner as
Fth (≡T.G) =ρGλ
Here T1 is the time interval from the onset of EMG to the moment of recruitment of a motor unit and ρ is a proportional constant. The motor unit with a positive/negative value of λ is characterized to be static/phasic.
Morimoto and Hasegawa reported that the above relation also holds for the relaxation period, provided that Ftn and G are replaced by the tension at the moment of silence and the absolute value of G, respectively. In this case, the motor unit with a positive/ negative value of λ is characterized to be phasic/static.
In order to investigate the characteristics of motor units during relaxation period under the influence of pre-relaxation states, such as the increase of tension up to 4kg at the gradient of 0.5kg/sec and the state sustained at 4.0kg for 30sec. Single motor units of m, vastus medialis were studied by the same method as that of Morimoto and Hasegawa.
The following results were obtained;
1) Both at contraction and relaxation periods, the above relation was confirmed.
2) The motor unit with characteristics of recruitment modes was influenced by the pre-relaxation state, but its tendency was not definite. These results suggest that phasic/static characteristics of motor units are not stationary but fluctuate depending on the pre-relaxation states.View full abstractDownload PDF (492K) -
—A STUDY OF THE MULTIPLE CASES—AKIRA SAKAGUCHI, KOICHI TSUNODA1977 Volume 26 Issue 2 Pages 64-69
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSAs the static balancing ability of the body is physiologically so complicated, that it is not easy to appraise it objectively and quantitatively. The aim of this study is to asses the motion of the gravity center of the body, using the body-balance analyzer (MGC-O1A, TOSHIBA), and to evaluate the validity of its use in the physical testing system.
The trace of the motion of the gravity center of 30 second duration, while the subject standing quietly on the sense-table with his eyes closed and his toes 60 degree opened, was drawn on the chart sheet and its length (L) was calculated electronically.
Preliminarily, 14 healthy men and women, whose ages ranged from 21 to 48 years old, were subjected to the test six times every day for ten consecutive days. The L values of 60 time measurements of each subject showed a slightly eccentric distribution with the coefficient variation of 20% on the average, but the coefficient variations of logarithmic value of L were small and they were between 2.4 and 6.0%. There was no significant difference between the L in the morning and that in the afternoon. Well-trained subjects seemed to show the smaller L values than the not-trained, but the latter some-times had little values, which might perhaps tell the existance of some predispositional ability for body balancing. Half of the subjects showed a“training effect”; L became smaller as the experimental day went on.
The L values of 2212 male and female subjects, age of those ranging from 19 to 83 years old, who performed the general physical testing, were then analyzed. The distribution of L was that of a “logarithmic normal”and it's geometric mean value was 210.8cm per 30 seconds, where the range of ± 1 S.D. was 149.0-298.3. It seemed that L increased with aging, only with a very low correlation coefficient (r : 0.14) . And there was no significant difference in L values between male and female. Although the multivariate analyses, in which L was set as the object variable, was performed, the correlation between L and the other physical abilities (muscular strength, power, agility, flexibility. and VO2max) was very low (r : lower than 0.12) .View full abstractDownload PDF (653K) -
HIROSHI KURATA, HIDESHI HASEGAWA, SHIGERU MORIMOTO, YOSHIKI UMAZUME, M ...1977 Volume 26 Issue 2 Pages 70-77
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIn this study, the relationships between the contractile properties of human motor units and their discharge patterns, characteristics of recruitment and others were examined. Action potentials of single human motor units in m, extensor digiterumwere detected by use of an inserted electrode. Tension curves of single motor units were recorded under the conditions that tension in finger extension was gradually increased, and that the subject relaxed his muscle as soon as he observed a sweep on a Braun tube triggered by the action potential of a single motor unit. About 100 twitch tension curves were summed up to obtain the average tension curve of a single motor unit. The τ-S diagrams were obtained from the mean discharge intervals (τ) of motor units at various sustained tensions and their standard deviations (S) . The λ values were also obtained from the relation Fth (-T1G) =ρGλ.
It was observed that the contraction time of the twitch tension curve of single human motor unit in a muscle was nearly proportional to τs (the τ values at a constant S value) . We presume that the regularity of discharging of motor unit affects the contraction speed in human muscle, because the motor unit with more regular discharging has longer contraction time of twitch.View full abstractDownload PDF (1536K) -
M. ONO, F. TANISHIMA, M. WATANABE, Y. OGAWA, Y. TANI, M. MATSUI, J. HI ...1977 Volume 26 Issue 2 Pages 78-86
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSFourteen males of ages between 20-55 years and nine females of 19-26 years, all in good health, were tested in push-ups, upon which the following results were obtained.
1. While the push-up exercise until exhaustion causes increase in heart rate and systolic blood pressure, the rate of increase in these items seem to become greater as the age grows.
2. The push-up exercise until exhaustion seemed to affect the diastolic blood pressure in the manner that it decreases among those who are relatively young and that it does not necessarily change or increases among those older than middle age.
3. Certain differences were found between both sexes in the effects of push-up exercise until exhaustion. Greater rate of increase in heart rate and systolic blood pressure were observed among men than women. When diastolic blood pressure decreases, male subjects showed a consistant linear decrement pattern, while female subjects tended to increase slightly before such decrement started.
4. Older subjects demonstrated greater differences between the effects of push-up exercise until exhaustion and its two-thirds load on circulatory functions than younger subjects, and so did males than females. The decrease tendency of diastolic blood pres-sure among young males when push-up exercise until exhaustion was performed was not revealed when its two-thirds load was administered.
5. The retative metabolic rate of push-up exercise until exhaustion was measured to be approximately 10 and the amount of oxygen debt was relatively large.View full abstractDownload PDF (875K) -
SHOICHI YAMAZAKI, JUNICHIRO AOKI1977 Volume 26 Issue 2 Pages 87-95
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESS(1) The purpose of the present study was to investigate the significance of anaero-bic energy release in two groups of distance runners whose maximal aerobic power was known to be comparable (Vo2max averaged 71.1±1.22 ml/kg· min) but differed each other significantly in their performance of 5, 000m run (group A ; n=6, timed in average 14'50″1±11″0 ; and group B ; n=6, timed in average 15'52″5±14″1) .
(2) Twelve runners were subjected to 3 experimental series of treadmill running 1, exhaustive running, 2, two to four trials' of submaximal runnings for 15 min, and 3. running at the intensity corresponding to 90% of maximal oxygen uptake for 14 min, then the“last spurt”for 1 min at 120% of maximal oxygen uptake. In addition, they were asked to sprint up a staircase with their top speed.
(3) Exhaustive running time on the treadmill and maximal oxygen debt in group A were 8'56″2±40″8 and 8454±923.7 ml, respectively. Both were significantly larger than 8'02″8±31″0 and 6787±1301.7 ml registered by group B (p<0.05) .
(4) Differences between A and B groups in their cardio-respiratory responses during maximal treadmill running, threshold of anaerobic metabolism, anaerobic power, alactic and lactic oxygen debt, maximal lactate concentration, etc. were found to be not significant.
(5) These results indicate that the variance in maximal oxygen debt may exert a modifying influence in either positive or negative directions which could be the reason why the same level of aerobic power does not guarantee a comparable performance level in actual running event.View full abstractDownload PDF (950K) -
SHOICHI NAKANO, TOSHITADA YOSHIOKA, MITSUO NARUSAWA, KUNIATSU NAGAMI, ...1977 Volume 26 Issue 2 Pages 96-100
Published: June 01, 1977
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIn the present studies it was examined to begin with, whether intentional fixed quantity of exercise in response to previously defined level of heart rate could be loaded by treadmill connected with“Heart Rate Controller” (Quinton Co., Ltd.) i.e. a series of patterns in running exercise of the normal adult males were analysed.
The obtained results in short are in the following ;
1) Running exercise in response to previously defined level of heart rate being carried out by use of the above“Heart Rate Controler”, speed of treadmill needed to be adjusted manually until heart rate reached the defined level and then controlled automatically.
2) The relations between treadmill speed and heart rate defined at 130 Beats/min, 150 or 170 each, are as follows.
a) Treadmill speed at heart rate, previously defined as 130 B/min was 80±5-12 meters/min, actual heart rate during above exercise was 130±3-8 B/min in record.
b) Treadmill speed at heart rate, 150 B/min was 100±9-18 m/min, actual heart rate 150±6-8 B/min in record.
c) Treadmill speed at heart rate, 170 B/min was 130±10-33 m/min, actual heart rate 170±3-9 B/min in record.
As previously defined heart rate level was indreased, actual level in record deviated from the former within some extent and treadmill speed was also raised to maintain the defined heart rate level.
Fluctuation width of treadmill speed varied remarkably by the individuals.
Adjustment of treadmill speed was considered to be well under control by feedback mechanism of“Heart Rate Controller”.View full abstractDownload PDF (565K)
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