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Volume 44, Issue 1
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1995 Volume 44 Issue 1 Pages 1-95
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (19541K) -
HISAYA TSUZIMOTO, HIDEKI SUZUKI, NORIKATSU KASUGA, TOSHIHIRO ISHIKO1995 Volume 44 Issue 1 Pages 97-103
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSFour myosin heavy chain (MHC) isoforms were detected in rat hind-limb fast muscles. MHC isoforms are particularly good candidates for fiber type-specific markers in myofibril proteins. We studied the effect of running or jumping training on MHC isoform composition in 18, 6 month-old female rats. The animals were divided into three groups : sedentary (S; n=6), running (R; n=5) and jumping (J; n=7) at 4 months of age. Animals in group R were trained with treadmill running (30 m/min, 60 min/day and 5 days/wk) for 8 weeks. Animals in group J were trained with vertical jumping (40 cm high, 100 repetitions/day, 5 days/wk) for 8 weeks.
There was no significant difference in body weight among the groups. Muscle weight and muscle weight/body weight for the plantaris were significantly increased in both trained groups, but there was no significant difference in the protein concentration. With regard to MHC isoform composition, there was no significant difference in the compositions of the type I and type ha MHC isoforms. In the type lid MHC isoform, the values for both trained groups were significantly higher than that of group S (p<0.05) . The values for both trained groups in the type lib MHC isoform were lower than that of group S. In particular, there was a significant difference between groups S and J (p<0.05) .
These results indicate that a relative increment of the type lid MHC isoform is a typical adaptation phenomenon of the olantaris muscle in rats riven runninr and iumoinr training.View full abstractDownload PDF (2023K) -
TETSUYA TAKAHASHI, KAZUHIKO TANABE, MASARU NAKAYAMA, NAOHIKO OSADA, SU ...1995 Volume 44 Issue 1 Pages 105-112
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSThe difference in cardiopulmonary response between supine exercise and sitting exercise was assessed by the following protocols.
1) Cardiopulmonary exercise testing utilizing the ramp protocol with a bicycle ergometer (20 W/min) was performed by nine healthy Japanese men (mean age, 19.9 yr) in a sitting and a supine position. Oxygen uptake, heart rate and blood pressure were measured during the test. Blood was sampled in order to measure noradrenaline (NA) and angiotensin II (ANG II) in the resting control state and immediately after exercise.
2) Single-level exercise testing at 100 W was performed on another day. The cardiac index (CI) was computed from the cardiac output, which was measured using the dye-dilution method in the resting control state and during exercise.
The results were as follows:
1) Heart rate and blood pressure during exercise had a tendency to be lower in the supine position compared to the sitting position, although not significantly.
2) Anaerobic threshold (AT) was lower in the supine position than in the sitting position exercise, (18.3±2.6 ml/kg/min and 21.7±1.9 ml/kg/min, respectively) .
3) NA and ANG II in the supine position were slightly lower than in the sitting position.
4) At rest, the CI in the sitting position was significantly less than in the supine position; however, the CI during the 100 W exercises was the same in both the supine and sitting positions.
It is concluded that blood flow to active muscle during 100W exercise is lower in the supine than in the sitting position. This is thought to be due to changes in blood redistribution and lowered blood flow to active muscle in the supine position, creating a lower AT.View full abstractDownload PDF (840K) -
KEN-ICHI NIWA, YOSHIYUKI ARAKI1995 Volume 44 Issue 1 Pages 113-118
Published: February 01, 1995
Released on J-STAGE: December 10, 2010
JOURNAL FREE ACCESSTo examine the influence of warm-up on thermoregulatory responses during exercise, heat balance was measured in 5 healthy male students during lhr of exercise at 600 kpm/min work intensity in a climatic room of WBGT (Wet-Bulb Globe Temperature) at 30°C with or without pre-exercise warm-up at the minimum phase (6: 00-7: 00) of body temperature.
There was no significant difference in heat production between exercise with and without warm-up. Evaporative heat loss during exercise with warm-up was 4-8% higher than that without warm-up.
Warm-up did not influence dry heat loss. Body heat storage during exercise without warm-up was 36% higher than that with warm-up.
The slope of the characteristic curve between the sweating response and elevation of rectal temperature during exercise with warm-up was higher than that without warm-up. These results indicate that the increased evaporative heat loss resulting from warm-up is brought about by changes in the sensitivity of the thermoregulatory response.View full abstractDownload PDF (2182K) -
LISA YANO, HIROMI YANO, MASAYUKI WATANABE1995 Volume 44 Issue 1 Pages 119-126
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSPrevious studies of the effect of exercise on glucose metabolism in diabetes mellitus have focused on the stimulation of glucose disposal capacity by insulin and muscle contraction. We have investigated the effects of hyperglycemia on the increase in muscle glycogen after exercise and the role of physiological saline (saline) injection under hyperglycemic conditions. Male Wistar rats weighing 100-150g (n=52) were made diabetic (DM) by injection of 90 mg/kg streptozotocin (STZ) . Glycogen content was reduced by in situ electrical stimulation of the sciatic nerve. Immediately after stimulation, the rats were injected with glucose or saline. After a 20 min recovery period, the glycogen content of the white and red gastrocnemius (WG, RG), soleus (SOL), plantaris (PL), extensor digitorum longus (EDL) and tibialis anterior (TA) was significantly increased by glucose injection in the control rats. In DM rats, the glycogen content of the TA and EDL was increased, whereas there was no change in the WG, RG, SOL and PL. These results suggest that, in hyperglycemic rats, muscle glycogen resynthesis in only fast-twitch fibers is increased by muscle contraction. However, after injection of saline, the plasma osmolality decreases significantly and glycogen resynthesis by all muscles except the SOL in diabetic rats is improved, although there is no significant increase in control rats. It is concluded that glycogenolysis and resynthesis after muscle contraction are reduced by hyperglycemia. The data suggest a possible role of saline injection in the development of glycogen resynthesis in hyperglycemia.View full abstractDownload PDF (870K) -
NAN ZHANG, TAMOTSU TERAO, SHOICHI NAKANO1995 Volume 44 Issue 1 Pages 127-135
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSWe studied the effects of 8 weeks of endurance training on the metabolism in rats. Different treadmill speeds, which corresponded to 2 mM and 4 mM blood lactate concentrations, were used to vary the intensity of the endurance training. After 8 weeks of training, blood lactate concentrations had decreased whereas β-hydroxyacyl-CoA dehydrogenase activity had increased. Citrate synthase activity in the m.extensor digitorum longus (EDL), and m.tibialis anterior (TA) of rats trained at the 4 mM level was higher than in rats trained at the 2 mM level and in control rats. In addition, muscle glycogen content in the hindlimb was higher and muscle TG content in the m.soleus (SOL) was lower in trained rats. These results suggest that training at 4 mM level significantly increases muscle mitochondrial oxidative capacity, and fatty acids are utilized as an energy source regardless of exercise intensity at least in the 2 to 4 mM intensity range. We concludes that an intensity of 4 mM is a useful level with which to elucidate the various adaptations to endurance training.View full abstractDownload PDF (867K) -
TADASHI OKUMOTO, AYAKO SAITOH, HAJIME OHMORI, SHIGERU KATSUTA1995 Volume 44 Issue 1 Pages 137-146
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSThe present study was designed to determine whether conversion of fiber types (type I to II) induced by hindlimb unloading (HU) is identical along the length of fibers in the soleus (SOL) muscle. After 1 and 2 wk HU, SOL was divided into three (proximal, middle and distal) regions and the fiber type composition was determined using myosin adenosinetriphosphatase (ATPase) . There was no significant change in fiber type distribution after 1 wk of HU. The percentage of type I fibers significantly decreased in the proximal and middle regions and that of type IIc fibers increased in all regions after 2 wk of HU. The percentage of type IIc fibers greatly increased in the proximal and middle regions compared with the distal region. Serial cross-sections every 300μm were processed for myosin ATPase from the middle to the distal region, and then analyzed to show the differences in staining characteristics along the length of single fibers. After 2 wk of HU, some of the fibers (3.1±1.2%) displayed changes in the staining characteristics of myosin ATPase (pH 10.3) ; 84% of these fibers identified type IIc fibers in the middle region were observed as type I fibers in the distal region. These results suggest that muscle fibers in unloaded SOL may not transform synchronously or uniformly along their lengthView full abstractDownload PDF (2849K) -
—WITH SPECIAL REFERENCE TO STRENGTH AND POWER—KOJI ZUSHI, KAORU TAKAMATSU1995 Volume 44 Issue 1 Pages 147-154
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSLong jump and high jump, and several types of jumping and footwork with rapid changes in speed and direction of movement in ball games are characterized not only by a combination of eccentric and concentric movement (stretch-shortening cycle movement, SSC) but also a ballistic movement of very short duration (100-200 ms) . This study was conducted to examine the effects of strength and power on ballistic stretch-shortening cycle movement (BSSC) ability to clarify the methods of strength and power training necessary for jumpers and ball game players. The subjects were 99 male college athletes. The index for BSSC ability was RDJindex [RDJindex = (1/8⋅g⋅RDJta2) /RDJtc] which was calculated using contact time (RDJtc) and air time (RDJta) in a rebound drop jump from a height of 0.3 m with a small angular range of motion for the knee. The index for strength was maximum leg extension strength exerted in a squat position at a 90° knee angle (Smax/BW) . The index for power was the height of a counter movement jump (CMJh) . Results were summarized as follows;
(1) There were significant correlations between RDJindexand Smax/BW (r=0.219, p <0.05), RDJindexand CMJh (r=0.584, p<0.001), and Smax/BW and CMJh (r=0.487, p<0.001), but they were fairly low, suggesting that these indices do not have similar significance for estimating training effects and sports talent.
(2) There was no significant correlation between RDJtcand RDJta, of which the RDJindexwas composed (r=-0.145, ns) . This result suggests that BSSC ability consists of two independent abilities, i. e. the ability to jump higher and the ability to shorten one's movement time.
(3) There were significant correlations between RDJtaand Smax/BW (r=0.340, p<0.001), RDJtaand CMJh (r = 0.647, p <0.001), but not RDJtcand Smax/BW (r=0, 035, ns), or RDJtcand CMJh (r=-0.187, ns), suggesting that the ability to jump higher is affected by strength and power whereas the ability to shorten one's movement time is not.
(4) When subjects with equal RDJindexwere compared, one subject was dominant in RDJtc and another in RDJta. This result suggests that we should consider individual differences based on RDJtcand RDJtain training for increasing the RDJindex.
These findings seem to be useful to clarifying the methods of strength and power training for jumpers and ball game players who need to improve their ballistic stretch-shortening cycle movement ability.View full abstractDownload PDF (866K) -
YASUHIRO ITO, YOSHITO OGURI1995 Volume 44 Issue 1 Pages 155-161
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSBefore, and at various time intervals after a marathon race, we examined the changes in serum β -enolase concentration in 6 healthy, non-athlete volunteers and compared then with changes in serum creatine kinase (CK) and creative kinase MB isozyme (CK-MB) activities. The enzyme β-enolase (a β and ββ) exists in skeletal and heart muscle, where it catalyzes the step in the glycolytic pathway between 2-phosphoglycerate and phosphoenolpyruvate. For determination of β-enolase concentration, serum was analyzed by the sandwich enzyme immunoassay method. The β-enolase concentration was significantly increased from the pre-race value. At 6 h after the race, the β-enolase concentration became maximal in all subjects, while CK and CK-MB activities did so in one and two subjects, respectively. CK and CK-MB activities peaked at 24 h in five and four subjects, respectively. The rise and fall of β-enolase concentration was faster than those of CK and CK-MB activities. Therefore, assay of β-enolase concentration has considerable advantage for early detection of skeletal muscle damage and is highly specific and sensitive. The mean β-enolase concentration±S. D. before and immediately after, and 6, 24, 48 h and 1 week after the race was 7.7±5.96, 204±87.6, 400±292.0, 214±166.3, 41.1±30.89, and 6.5±2.20 ng/ml, respectively. There was a significant correlation between the peak β-enolase concentration and peak CK activity (r=0.981, p<0.05) and peak CK-MB activity (r=0.926, p<0.05) . However, there was no significant correlation between β-enolase concentration and Vo2max.
These results suggest that serum β-enolase concentration may be a more effective marker of skeletal muscle damage after prolonged exercise, as well as for determination of CK activity.View full abstractDownload PDF (762K) -
TOSHIAKI FURUBAYASHI, TOMOYOSHI KOMIYAMA1995 Volume 44 Issue 1 Pages 163-172
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSThe present study was undertaken to examine the effects of acoustic stimulation on human spinal motoneuron excitability. For this purpose, we used the soleus (Sol) H-reflex as a test reflex, and three different types of acoustic stimuli as conditioning stimuli. The features of the acoustic stimuli were as follows, 1) click sound (CS), 2) tone burst composed of 11 click sounds (TBL, interstimulus interval 10 ms), 3) tone burst composed of 21 click sounds (TBH, interstimulus interval 5 ms) . The intensity and frequency of each sound was 110 dB and 0.5 kHz, respectively.
Significant facilitation of the Sol H-reflex occurred at conditioning-testing (C-T) intervals of 50 ms in all subjects when the TBL stimulus was used (mean±S.D.; 50.3±8.2 ms) . This facilitatory effect appeared early and later when TBH (43.7±3.7 ms) and CS (59.2±4.5 ms) stimuli were used, respectively. The maximum facilitatory effect appeared at a C-T interval of 100 ms (mean and S. E.; 98.0±0.8 ms) and the amount of peak facilitation at that time was 156.1±1.4% (relative to the control value) . Thereafter, the amount of facilitation decreased sharply up to a C-T interval of 200 ms. However, slight but significant facilitation was observed continuously up to a C-T interval of 500 ms. No significant inhibition of the Sol H-reflex was observed between a C-T interval of 0 and 500 ms in all subjects.
Irrespective of whether the magnetic cortical stimulation was given before or after the Sol H-reflex at a short interval (-2 to 2 ms), the acoustic facilitation of the Sol H-reflex was not changed with a C-T interval of 50 ms. Additional facilitation due to magnetic cortical stimulation was, however, obtained in one of the four subjetcts when a C-T interval of 100 ms was used.
These results suggest that the acoustic facilitation of the Sol H-reflex is composed of three different facilitatory mechanisms; 1) a pathway with a high threshold and shorter latency (about 40 ms), 2) a pathway with a lower threshold and medium latency (about 60 ms), and 3) a pathway with a relativelyhigh threshold and longer latency (longer than 200 ms) . In addition, we discussed the mechanisms that underlie the facilitatory effects of the Sol H-reflex.View full abstractDownload PDF (1124K) -
[in Japanese]1995 Volume 44 Issue 1 Pages 173-179
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
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1995 Volume 44 Issue 1 Pages 181-189
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (1578K) -
1995 Volume 44 Issue 1 Pages 190-192
Published: February 01, 1995
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (412K)
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