The purpose of this study was to examine the relation between body composition and athletic performance of long distance relay runners in a four week weight reduction program. Six male collegiate runners, aged 19.0 ± 0.9 years, participated in this study. Body water content and fat free mass (FFM) were measured by bioelectrical impedance spectroscopy.The weight loss by 4.1% of the initial body weight consisted of decreases in FFM and fat mass (54% and 46% respectively). Percentage of body fat did not change significantly by the end of the fourth week. The total body water (TBW) loss comprised of intracellular water (ICW) and extracellular water (ECW) at the end of the fourth week, and TBW loss and FFM loss were nearly the same values. Isokinetic muscular strength of right thigh, maximal oxygen intake (VO₂max) and total treadmill running time (maximal workout time) measured did not show any significant change. These results indicate (1) half of the weight loss consisted of decrease in FFM, (2) TBW loss was due to the reduction of ICW and ECW, (3) the content of FFM loss was considered to be body water, and (4) there was no impact on muscular strength of right thigh, VO₂max or maximal workout time.

Penetration of different kinds of peptides or collagen peptide through the intestinal membrane was studied in two experiments using anin vitrorat everted intestine penetration model. In Study 1, twelve 11-wk-old rats (Wistar strain) were randomly divided into two groups and penetration of whey peptide (n=6) and soy peptide (n=6) through the intestinal membrane was compared. In Study 2, fourteen 11-wk-old rats (Wistar strain) were divided into a control group (n=7) and a training group (treadmill running at a speed of 20-35 m/min for 15 mm day, 5 days wk for 4 wk n=7), and penetration of collagen peptide through the intestinal membrane was investigated in the two groups. In Study 1, the quantity of whey peptide that penetrated through the intestinal membrane was significantly greater than that of soy peptide (P<0.01) . In Study 2, body weight was significantly lower in the training group than in the control group except during 12 and 12.5 wk of age (13.5 wk ; P<0.01, others; P<0.05) . The weights of heart, kidney, and spleen were significantly increased, and the weight of fat was significantly decreased in the training group compared to the control group (P<0.05, P<0.05, P<0.01, P<0.05, respectively) . In both groups, a portion of collagen peptide penetrated through the intestinal membrane; but there was no significant difference in quantity between the two groups. In conclusion, the inhibition of weight gain in the training group was possibly caused by decreased feeding from lack of appetite with enforced exercise. These findings suggest that whey peptide penetrated through the intestinal membrane in greater quantities than soy peptide, and collagen peptide is not affected by enforced exercise.

The purpose of this study was to analyze morphological and functional changes in the left ventricular muscle mass and vessel diameters of the arteries in young competitive athletes of various sports and evaluate the correlation between the heart and arterial vessel under the training environment in this latter half of the growth period. The subjects were 51 male college student athletes (mean age, 19.6±0.4 years) of 6 competitive sports (archery, weight lifting, swimming, short-distance races, middle-distance races, and long-distance races) . The diameters of the right and left common carotid arteries, right and left radial arteries, right and left foot dorsal arteries, and the aorta and the left ventricular muscle mass (LVM) were measured by Doppler echocardiography. To minimize the influences of the physique and body weight associated with growth and sport types, all data obtained by measurement were corrected by body surface area. The sum of the diameters of all the above arteries (total arterial diameter : TAD) was obtained to evaluate its correlation with the left ventricular muscle mass. The diameter of the foot dorsal artery was significantly higher in the long-distance runners than in the sprinters (P<0.05) . The diameter of the radial artery according to the 6 types of sport was the highest for weight lifting, followed in order by archery, longdistance races, middle-distance races, swimming, and short-distance races, showing a significant difference between weight lifting and short-distance races (P<0.05 ) . TAD was high for generalized endurance sports and correlated with the left ventricular muscle mass (r=0.893) . Thus, the arterial diameters significantly differed among competitive sports and were particularly increased for endurance exercise. The diameters of the local arteries used for local exercise were also increased. When TAD as a new parameter and its ratio per body surface area were calculated, there was a high correlation between the heart (left ventricular muscle mass) and the arterial diameter. These results suggest that exercise adaptation can he evaluated in the arterial system in svstemic circulation as well as the nervous and muscular systems.

The purpose of this study was to investigate the usage of the lower limb muscles (quadriceps femoris : QF, m. vastus lateralis : VL, m. rectus lemons : RF, m. vastus medialis : VM, m. vastus intermidialis : VI, hamstring : HM, m. gastrocnemius : UN, tihialis anterior : TA) and blood lactic acid concentration during uphill ( : UR +5 %) and downhill running ( : DR - 5 %) . We used magnetic resonance imaging (MRI) as one of the major indices. Seven healthy male volunteers participated in this study. T 2-weighted MR imaging, muscle surface temperature and blood lactic acid concentration were measured before and after UR and DR. In MRI imaging, the T2 value was defined as the area in which a high signal appeared after exercise.
The value of the blood lactic acid concentration of UR was higher than that of DR (p<0.001) . After DR, the muscle surface temperature of RF was lower in comparison with other muscles (p< 0.05) . After UR, the T2 value of RF (p<0.05), HM (p<0.01) and UN (p<0.05) was higher than after DR exercise. During UR, a positive correlation (r=0.818) existed between the T 2 value of GN and blood lactic acid concentration (P<0.05) . During DR, a positive correlation (r=0.739) was also observed between the T 2 value of QF and blood lactic acid concentration (p<0.05) .
From these results, we conclude that (1) the pattern of usage of lower limb muscles differs during UR and DR, (2) the most mobilized muscles in the lower limbs for UR are GN and HM, and (3) the most mobilized muscle in the lower limbs for DR is QF, respectively. These findings show that different exercises affect the blood lactic acid concentration differently.

Purpose: The purpose of this study was to examine the relationship among helmet surface temperature (Thl), head top temperature (Thd) and tympanic temperature (Tty) during American football practice in summer. Methods : The subjects were collegiate American football players. Temperatures were measured in August in 1993 and 1994. Thl, Thd and Tty were measured by infrared tympanic thermometers. Environmental temperatures that were measured were dry-bulb temperature (Td), wet-bulb temperature (Tw), globe temperature (GT) and wet-bulb globe temperature (WBGT) . Results: Significant correlations were observed among all measured temperatures (P<0.0001) . High coefficients of correlation were observed among Thl, Thd and GT. The highest relationships were observed between Thl and Thd (r=.727), and between Tty and Td (r=.766) . The coefficient of correlation between Tty and Thl was higher than that between Tty and Thd. Heat stress of the whole body (F1; heat stress factor: Tty, Td, Tw and WBGT, proportion=71.4%) and head environment factor (F2 ; helmet factor : Thl, Thd and GT, proportion=14.3%) were chosen in factor analysis. A close relationship was observed between both factors (r=.773) . Both GT and Thl showed a high correlation with Thd, which suggests the influence of radiant heat through a helmet on the whole body. Conclusion : The temperature in a helmet is a micro environment temperature surrounding the head. Accordingly, the heat load is reduced by taking the helmet off frequently during football practice.

The purpose of this study was to analyze the relationship between activity pattern and temporal changes in the oxygen dynamics of human femoral medial vastus muscles. Oxygen dynamics were evaluated from the surface of the body by near-infrared spectroscopy (NIRS) . Arterial occlusion tests were performed in the femoral region at a cuff pressure of 300 mmHg. Exercise type and speed were controlled by CYBEX 6000. The exercise types examined were concentric contraction (CON) and eccentric contraction (ECC) . The 3 angular velocities of 90, 120 and 180 degrees were used as the exercise speeds. Exercise was performed continuously 60 times at maximum effort. The subjects were 7 healthy males with a mean age of 19.6±0.5 years. A transient decrease in oxygen concentration was observed during circulatory occlusion ; and rapid hyperemia occurred immediately after the removal of pressure. Oxygen concentration peaked above the control level and then returned to the initial level. In the CON exercise, the initial decrease in oxygen concentration was the largest at CON 90, and a gradual increase in oxygen concentration was clearly observed during exercise. In the recovery stage, after exercise at CON 90, 120 and 180, oxygen concentration exceeded the control level before exercise, then peaked and returned to the initial level. In the ECC exercise, an initial decrease in oxygen concentration was similar to that in the CON exercise, but a gradual increase in oxygen concentration was not observed during the exercise ; nor did oxygen concentration exceed the control level in the recovery stage after the exercise.
These results indicate that an increase in oxygen level after the removal of arterial occlusion, during and after the CON exercise was much higher than the control level before the exercise, sug-gesting the involvement of reactive hyperemia and exercise hyperemia.

We 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.

A study was performed to investigate the effect of ingestion of two different carbohydrates immediately after exhaustive exercise on muscle glycogen restoration in rats. The carbohydrate solu-tions used were 20% maltodextrin (osmolality: 270 mOsm/kg⋅H₂O) and 20% glucose (osmolality: 1370mOsm/kg·H₂O) . At both 30 and 60 min after oral ingestion, the osmolality in the gastric residue was significantly higher in the group given the glucose solution than in the group given the maltodextrin solution. The concentration of serum glucose at both 30 and 60 min after oral ingestion was significantly higher in the group given maltodextrin than in the group given glucose. Compared to the group given glucose, the group given maltodextrin had significantly higher muscle glycogen contents in M. plantaris and M. gastrocnemius at both 30 and 60 min after oral ingestion. Furthermore, the muscle glycogen contents in the group given maltodextrin returned to the levels in resting control rats 60 min after oral ingestion. Thus it is concluded that ingestion of maltodextrin solution immediately after exhaustive exercise might be effective for rapid restoration of muscle glycogen.

Changes in the numbers of muscle fibers and proliferating cells detected by immunohistochemistry were studied in correlation with various growth parameters including changes in body weight, lower hindlimb length, muscle length, muscle weight and age in Wistar-strain rats at various developmental stages. The total fiber number in plantaris (PLA) muscles increased gradually between 2 weeks and 10 weeks of age (about 300g body weight), and then remained constant between 10, 000 and 11, 000 these after. In contrast, proliferating cells labeled by bromodeoxyuridine decreased gradually during the same period, and were hardly evident after 10 weeks. In the growth curves for the body weight, lower hindlimb length, muscle weight, and the length of the extensor digitorum longus (EDL) muscle, turning points were observed at 10 weeks (300 g body weight), respectively, suggesting that the turning point between growth in length and growth in width occurred at this point. Furthermore, the growth curves for the body weight and PLA muscle weight were correlated between 2 and 20 weeks, including the turning point. Therefore it is suggested that the development of muscle weight from 2 to 10 weeks depends mainly on the increment of fiber number (hyperplasia), whereas development after 10 weeks depends on the increment of individual fiber diameter (hypertrophy), in relation to the tendency for an increase in fiber number and a decrease in proliferating cells. These results indicate that maturation of skeletal muscle in male Wistar rats occurs at 10 weeks of age and a body weight of 300g. Accordingly, these facts should be considered when investigating muscle hypertrophy or hyperplasia.

The effects of 6 weeks (5 days/week) of endurance training under hyperoxia (60% O₂ plus 40% N₂) on carbohydrate and fat metabolism were studied in 42 male rats. The rats were divided into four groups ; normoxia control (NC, n=8), hyperoxia control (HC, n=9), normoxia training (NT, n=12), and hyperoxia training (HT, n=13) . NT and HT groups were made to run on a treadmill in a metabolic chamber at a speed of 20 m/min for 30 min. The metabolic chamber was perfused with hyperoxic gas. VCO₂ values at rest (HC) and during exercise (HT) under hyperoxia were significantly lower (p<0.01) than VCO₂ values at rest (NC) and during exercise (NT) under normoxia, respectively. These results appear to indicate that a decreased respiratory exchange ratio was induced by hyperoxia. The results showed that at 15 min after the last training there were no differences between NT and HT in the glycogen or triglyceride content of the liver, heart, m, gastrocnemius, and m. soleus. However, blood glucose at 15 min in NT (109±13 mg/dl) was significantly lower (p<0.05) than the corresponding value at 15 min in HT (133±11 mg/dl) and at 48 h after the last training in NT (149±7 mg/dl) . The glycogen content of the liver in HC (36.4±2.6 mg/g wet wt) was significantly higher (p<0.05) than the corresponding value in NC (26.1±1.9 mg/g wet wt) . In the HT group, the triglyceride content of the liver at 48 h was lower (p<0.01) than the corresponding value at 15 min. However, the triglyceride content of the heart at 48 h in HT was significantly higher (p<0.05) than the value at 15 min. Basal lipolysis in HC was significantly higher than the corresponding values in NC, NT and HT, but there were no differences among the groups in norepinephrine-induced lipolysis. These results indicate that endurance training under hyperoxia might alter the content of tissue glycogen and triglyceride as a result of decreased carbohydrate consumption and increased fat utilization during fasting and/or exercise.