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Volume 45 (1996)
- Issue 6 Pages 565-
- Issue 5 Pages 477-
- Issue 4 Pages 413-
- Issue 3 Pages 377-
- Issue 2 Pages 289-
- Issue 1 Pages 1-
Volume 45, Issue 4
Displaying 1-7 of 7 articles from this issue
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AKINOBU WAKAYAMA, HITOSHI YANAGI, TOSHIHISA KOJIMA, MAKI YAMANE, MASAA ...1996 Volume 45 Issue 4 Pages 413-418
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSIn recent years, the knee extensor forces of athletes have usually been evaluated by measuring isokinetic output torque. The purpose of this study was to confirm the usefulness of normalizing the torque (force) -velocity curve and calculating the maximal power of knee extensor under isokinetic contraction.
Seventy two (46 elite, 26 non-elite) Japanese male sprinters were chosen as the subjects in this study. The peak torque of the dominant side of knee extensor was measured by using the isokinetic dynamometer (Cybex II+) in three different angular velocities of 60, 180, 300 deg/sec. Moreover, the isometric torque (0 deg/sec) was measured in 39 athletes, 120 and 240 deg/sec of contraction were performed in 12 out of 39 athletes.
The exponent equation (F = Fo× eav- kv : Fenn 1935) was applied to normalize the torquevelocity curve without including the coefficient of viscosity (k) . The maximal power and its optimal velocity was presumed from this torque-velocity curve. The average of measured torque at 0 deg/sec contraction (F0) was lower than that of 60 deg/sec, thereforeF0was presumed as the same as the maximal power. Those parameters were not significantly different when calculated from 3 velocities (60, 180, 300 deg/sec) and 5 velocities (plus 120, 240 deg/sec) in 12 athletes. For this reason, each parameter was calculated from 3 velocities.
The maximal torque (F0/BW) was the same between elite and non-elite group (4.0 Nm/kg) . Nevertheless, the coefficient of torque loss (a), maximal power and its optimal velocity were significantly different (-0.1586 : -0.1908, 9.6 : 7.8 watt/kg, 373: 309 deg/sec, respectively. P<0.01 Student-t) . It was said that to normalize the torque-velocity curve or to presume the maximal knee extension power and its optimal velocity were useful to assess the muscle function or the performance of athletes under isokinetic contraction.View full abstractDownload PDF (615K) -
GOROH OKANO, YUJI SATO, HOWARD TARNOFF, ISAMU NEMOTO, AKIRA NAKAMOTO, ...1996 Volume 45 Issue 4 Pages 419-427
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSThis study investigated the desire and its reasons for weight loss, the prevalence of disordered eating patterns and menstrual status, by using written questionnaires and Eating Attitude Test-26 (EAT-26), in Japanese female athletes (n=1000) and nonathletic controls (n=593) . Athletes were divided into the following 6 categories : technical (n=84), endurance I (n=84) and II (n=76), aesthetic (n=120), ball-game (n=447), and power sports (n=189) . Endurance I consisted of athletes competing in sports where leanness were considered important, while endurance II consisted of athletes competing in sports where leanness is less important. In each category, about four fifths of the athletes wanted to reduce their present weight. As to the reasons for weight loss, the athletes, especially those in the categories of endurance I (79%), power (52%) and aesthetic (34%) sports, reported that they prefer to be thin for improving their athletic performance. The prevalence of disordered eating patterns estimated by EAT-26 was significantly higher (P<0.05) in the athletes of endurance I (20%) and aesthetic (12%) groups than in the nonathletic controls (3 %) . In the athletes of these two sporting event categories, higher rates of amenorrhea (endurance I 20% and aesthetic 7 % vs. nonathlets 1 %) were found to be accompanied by lower values of obesity index and BMI. These data indicate a significantly higher prevalence of disordered eating patterns and menstrual dysfunction in the athletes involved in sports where leanness is emphasized, and a close relationship among undernutrition, low body weight and menstrual dysfunction.View full abstractDownload PDF (867K) -
KAZUKI ESAKI, HIROYUKI MIYAGAMI, YOSHIO EN1996 Volume 45 Issue 4 Pages 429-439
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSFor the purpose of examining relative impact of the middle-distance triathlon race (Swim : 2.0 km, Bike : 90.0 km, Run : 21.0 km), blood samples were taken on the day before, immediately after, and the day following the race from triathletes who participated in a middle-distance triathlon race at Tokunoshima, Kagoshima in June 1993. White blood cell count was significantly increased immediately after the race.It was recovered on the next day to the value observed before the race. Serum creatine phosphokinase activity was elevated significantly immediately after the competition. It continued to rise up to the level of about 4 times higher than the pre-race value. In terms of renal function, serum creatinine concentration showed a significant increase immediately after the competition. However, it recovered to normal range by the day after the competition. In addition, serum urea nitrogen concentration was also significantly increased after the competition. It remained at the high level until the day after the competition. In conclusion, it might be suggested that the middle-distance triathlon gives a significant impact on human body, even though it is quntitatively less than the long-distance type (Swim : 3.9 km, Bike : 180.2 km, Run : 42.2 km) .View full abstractDownload PDF (1214K) -
KAZUYOSHI GAMADA, HIROYUKI NAKAJIMA, SHINICHIRO SHIOZAWA1996 Volume 45 Issue 4 Pages 441-450
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSTrunk motion and the mechanisms of postural control during pedaling was investigated by analyzing the lower trunk muscle activity and spinal motion.
Eight healthy adult men were assigned to pedal at the rate of 60 cycles per min. with the load of 100 W, 150 W and 200 W. Muscle activity was recorded with the surface electrodes from the m. multifidus, m, iliocostalis, m. obliquus externus, m; rectus abdominis, m. rectus lemons, m. adductor longus and m. semitendinosus. Spinal motion was filmed with 8 mm video camera located 5 m behind the subject and 1 m above the floor, and five markers were attached on the midline of the spine (C 7, Th 6, Th 12, S 1, Co) .
Muscle activity (iEMG) was quantified by integrating one cycle of recorded electromyogram, and significant increase was recognized in the trunk muscles and m. rectus femoris as the load increased. The angles between each segments were calculated and the largest deviation was observed in the lumbo-sacral portion. Focussing on the activity of the m. obliquus externus, four patterns of controling the trunk posture were observed, and as the load increased, the activity patterns changed in four subjects and the other four showed tremendous increase in iEMG without changing the pattern.
The results sugest that the pedaling may cause relatively large motion at lambo-sacral portion of the spine, and either the change in the activity pattern or the increase in the activity level of the trunk muscles, such as m, obliquus externus, should contribute to reduce the stress on the lambo-sacral portion.View full abstractDownload PDF (1063K) -
KATSUHIKO SUZUKI, HIDEKI SATO, TETSU ENDO, HIROKO HASEGAWA, MITSUKUNI ...1996 Volume 45 Issue 4 Pages 451-460
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSTwenty endurance-trained athletes (five male speed-skaters, eleven male and four female cross-country skiers, 16-18 years) ran on a treadmill by a protocol of incremental graded increase in workload until exhaustion during an endurance training period in off-season summer. Immediately after exercise, all developed peripheral leukocytosis (1.9 times; p<0.01) due mainly to lymphocytosis (2.6 times; p<0.01) with a predominant effect on large granular lymphocyte (natural killer cell) count (5.9 times ; p<0.01) . Monocyte count was also enhanced 2.3 times (p<0.01) . These increases were transitory and returned to the pre-exercise levels 1 h later. Peripheral neutrophilia was also observed by 43% (p<0.01) immediately after exercise and remained elevated by 25% (p<0.01) 1 h after exercise, but a shift to the left did not take place. The capacity of isolated neutrophils to produce reactive oxygen species was assessed by luminol-dependent chemiluminescence which detects mainly myeloperoxidase (MPO) -mediated formation of such hyperreactive oxidants as HOCl. The maximum intensity of chemiluminescence (peak height) upon stimulation with opsonized zymosan was significantly enhanced following exercise (p<0.05) . Similar results were obtained when phorbol myristate acetate was employed as nonphagocytic soluble stimulus (p<0.01), suggesting that the capacity of neutrophils to degranulate MPO rather than phagocytosis was enhanced following exercise. In addition, the enhancements of chemiluminescence were positively correlated with the increase in segmented neutrophil count. These data indicate that maximal exercise not only mobilized mature neutrophils from the marginated pool into the circulation, but also augmented their capacity to generate reactive oxygen species of higher reactivity.View full abstractDownload PDF (1386K) -
[in Japanese]1996 Volume 45 Issue 4 Pages 461-464
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (374K) -
1996 Volume 45 Issue 4 Pages 465-475
Published: August 01, 1996
Released on J-STAGE: September 30, 2010
JOURNAL FREE ACCESSDownload PDF (1870K)
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