A study was conducted to examine the effects of exhaustive enduring exercise training on the skeletal muscle of rats. Twenty-six male Wistar rats were divided into 3 groups : an exhaustive training group (EE), a free-eating control group (Co), and a pair weight group in which body weight was matched to EE (PW) . The rats in EE were forced to run on a treadmill with an inclination of 0-3°, 6 days/week for 4 weeks. At first the rats ran at a constant speed for 60 min. Then we gradually added 2 m/min to the basic speed every minute until they were exhausted. The treadmill speed was 20 m/min during the first, 30 m/min during the second, 35 m/min during the third, and 40 m/min during the final week. The muscle wet weight, the quantity of the muscle protein and the isometric tetanic force were measured with the soleus and extensor digitorum longus (EDL) . Food restriction induced significant decreases in EDL weight. Exhaustive enduring exercise training induced noteworthy decreases in soleus weight, but remarkable gains in EDL weight. It also induced significant changes of the quantity of the muscle protein in the two muscles, which corresponded to the changes in muscle weight. The isometric tetanic force of both muscles was not affected by food restriction. The isometric tetanic force showed a significant decreases in EDL in EE comparison Co. The isometric tetanic force of the soleus did not show a significant decreases. However, its degree of decrease corresponded to that of the muscle protein. These findings illustrate that exhaustive endurance exercise training induces degradation of the soleus and hypertrophy of the EDL. However, it also decrease the muscle force which generats the capacity of the two muscles. We think that this phenomenon depends on the skeletal muscle characteristics, such as fiber type, and eccentric or concentric contraction.

The effect of a treadmill running program on the metabolism of cholesterol in liver was studied in male Wistar rats, aged 7 weeks and weighing about 200 g. Rats were exercised on 6 days a week for 8 weeks, running 1, 000 m a day at 15 m/min. The trained rats gave following evidence, as compared with the sedentary control animals:
1. Remarkable lower weight of body and liver
2. Significantly lower level of total and free cholesterol in liver
3. Elevated in vivo incorporation of¹⁴C-acetate and of¹⁴C-mevalonate into liver cholesterol
4. Enhanced incorporation of¹⁴C-mevalonate into cholesterol by liver slice
5. Increased activity of hydroxymethylglutaryl-coenzyme A reductase in liver
6. Increase in cholesterol 7 a-hydroxylase activity in liver
The results indicate that the exercise promotes the turnover of cholesterol in liver.

The effect of voluntary exercise training and influence of saline loading on blood pressure and cholesterol metabolism in rats were investigated in this study. Experimental animals used were male Wistar strain rats, aged 7 weeks old. These rats were allocated respectively into four groups, each of which consisted of 10 rats; sedentary control (SC), sedentary with 1 % saline loading (SS), training control (TC), and training with 1 % saline loading (TS) . In each of groups rats were sacrificed at the 10 th week.
Following results were obtained in this study.
1) The mean values of systolic blood pressure remained unchanged in all four groups, 2) serum and hepatic cholesterol levels were lowered by 10 weeks of exercise training, 3) the ratio of HDL-cholesterol to total cholesterol increased significantly in the training groups compared to that in the sedentary groups, 4) the incorporation of ¹⁴C-acetate into liver cholesterol was significantly lower in the SS group than in the SC group, and 5) a direct correlationship was found between the increased exercise level and the incorporation of acetate into liver cholesterol in both TC and TS groups.

The effect of a treadmill running program on the metabolism of cholesterol in serum and in arterial wall was studied in male Wistar rats, aged 7 weeks and weighing about 200 g- Rats were exercised on 6 days a week for 8 week, running 1, 000 m a day at 15 m/min. The trained rats gave the follwing evidence, as compared with the sedentary control animals:
1. Remarkably lower body weight
2. Significantly lower level of serum cholesterol-total, free, and LDL cholesterol
3. Elevated in vivo incorporation of ¹⁴C-mevalonate into serum cholesterol
4. Enhancement of lecithin-cholesterol acyltransferase activity in serum
5. Decrease in the amount of cholesterol in arterial wall cells
6. Increase in in vivo incorporation of ¹⁴C-mevalonate into arterial cholesterol.
The results indicate that the excersice promotes the turnover of cholesterol in serum and arterial wall, repressing the accumulation of choleterol ester in arterial wall cells, and a prophylactic effect of the physical training for arteriosclerotic diseases has been suggested.

The purpose of this study was to examine the effects of physical training on red blood cell properties, in particular red cell 2, 3-diphosphoglycerate (2, 3-DPG) and aerobic work capacity. The subjects were 28 healthy men and they were divided into three groups: Group 1 (12 athletes-long distance runners, cross country skiers performing daily aerobic training), Group 2 (8 athletes-sprinters (400 m), alpine skiers playing aerobic and anaerobic training every day) and Control (8 untrained persons) .
The results obtained were as follows:
1) In aerobic work capacity (VO₂max/w, O₂ pulse max) there was significant difference (p<0.01) among 3 groups (Group 1>Group 2>Control) .
2) Red blood cell properties (RBC, Hb, Hct) of each group showed no significant difference. However MCH, MCHC of Group 1 was significantly lower than Group 2 and Control, MCV was also a tendency to be lower. Red cell 2, 3-DPG concentration was significantly higher in Group 1, 2 as compared with Control. But there was no significant difference between Group 1 and Group 2.
3) Red cell distribution curve of Group 1 tended to shift to the left in comparison with other two groups.
4) The relationship between VO₂max/w and red cell 2, 3-DPG significantly correlated for all subjects composing the three groups. In addition a significant correlation was found for Group 1.

The purpose of this study was to observe the effect of training on morphological properties in the collagen fibers of tendons. Wistar strain rats at 7 weeks old were assigned to high speed endurance (H), moderate speed endurance (M), jump training (J) and control (C) groups. The amount of exercise for H group (speed at 30m/min for 60 minutes) and M group (speed at 17m/min for 75 minutes) was equalized according to the amount of oxygen consumed during training. As for the anaerobic training (J group), rats made high jumping form the standing position, wearing jacket with 50% of body weight, 50 times/day, which lasted for 4-5 minutes. The training period was designed for 5 days per week for 16 weeks.
The follwing is a summary of the results obtained:
1) Increases in fiber areas of both Slow-Twitch (ST) and Fast-Twitch (FT) fibers were observed in the H, M and J groups. The ST fiber area of H group was significantly larger than that of C group. Significant increase in FT fiber area was observed in both M and J groups.
2) Hypertrophy of collagen fiber in gastrocnemius muscle tendon was observed in Hand M groups; especially, M group showed much larger increase than H group. It tended to be greater for J group as compared with C group.
3) Collagen fiber area and diameter of tendon in plantar muscle were slightly larger for H and M groups relative to C group, but these differences were not significant.
These results suggested that both types of aerobic training induced hypertrophy in the collagen fibers of the tendons and increased the tensile strength; especially, the group which trained longer hours induced the higher effect.

Effects of treadmill running and restricted food intake on the metabolism of protein in several tissues were studied in male Wistar rats, aged 5 weeks and weighing about 100 g. Rats were divided into control group under free food intake (C), sedentary group under restricted food intake (Sr), exercise group under restricted food intake (Er), Food intake was restricted approximately to 66% of fed ad libitum for control group. Exercise program consisted of treadmill running for 60 minutes a day at 30 m/min on 6 days a week for 12 weeks.
A. The effects of sedentary under restricted food intake.
When compared with C
1) Lowering of body weight and increment in mg tissue/g body weight ratios. (M. Gastrocnemius, Liver, Brain, Testis, M. Soleus, M. Plantaris)
2) Significantly low level of protein content in gastrocnemius muscles, liver and kidney.
3) Inhibition in incorporation of ¹⁴C-amino acid mixture into brain and kidney protein in vivo.
B. The effects of exercise under restricted food intake.
i) compared with C
The effects were the same as those of Sr.
ii) compared with Sr
1) Lowering of body weight and increment in mg tissue/g body weight ratios. (Liver, Heart, Kidney, Testis)
2) Significantly low level of protein content in gastrocnemius muscles.
From this study it was suggested that, under the food restriction of long duration, the maintenance of protein content in brain in spite of the decrease of protein content in the other tissues indicated the existence of internal mechanism for life conservation in severe environment. And loaded with exercise under food restriction, protein content in gastra cnemius muscles decreased. Therefore, it was conceivable that skeletal muscles protein was consumed as energy for exercise.

With disuse, e. g. that resulting from tail-suspension, skeletal muscle shows a decrease in both mass and strength, with concomitant atrophy. Type IIc fibers are observed during muscle fiber generation, regeneration and fiber type transformation. Thus, the recovery process of atrophied muscle fibers can be investigated by observing changes in type IIc fiber distribution. In this study, the behavior of type IIc fibers was examined in rats during recovery following 5 weeks of tail-suspension. Male rats were assigned to three groups : control (C), tailsuspension (S), and pair-weight (P), in which body weight was adjusted to that of the S group by controlled food consumption.
The results were as follows : 1) After 5 weeks of tail-suspension, the weight of the m. soleus in the S group was less than 40% of that in the C group. 2) Weights of all muscles removed in the S group increased rapidly until 2 weeks into the recovery period, and returned to the level in the P group by 5 weeks. 3) Type IIc fiber distribution in the m, soleus in the S group was increased by about 35% after 5 weeks of tail-suspension, and had not returned to the level in the C group by 5 weeks of recovery. 4) Phanocytosis and central nuclei were observed in the atrophic muscle fibers of the S group.

A study was conducted to investigate changes in muscle soreness, serum creatine kinase (CK) activity and white blood cell (WBC) count following exercise bouts spaced three weeks apart.
The subjects were six male students (aged 23-25 yr), who had not participated in any training program for over 18 months. They performed muscular exercise of the nondominant arm using elbow flexors. Twenty percent of maximum voluntary contraction was used as the exercise intensity. After three weeks, the subjects repeated the same exercise bout. Perceived muscle soreness, CK activity and WBC count were assessed before, immediately after, 6h after and over 9 days after each exercise bout.
After the first exercise bout (1 st Ex), the subjects experienced muscle sorenss for 3-7 days. Also, a large increase of CK was found in five subjects (266-763%) . When the peak CK efflux was observed (day 3-4 after exercise), soreness had almost disappeared. WBC count was increased immediately and 6 h after exercise, then returned to the resting level. However, a significant increase (p<0.05) in WBC count was observed again on day 7 after exercise when CK had returned to the resting level. After the second exercise (2 nd Ex), a significant decrease of muscle soreness and the CK response was found in comparison with the 1 st Ex (p<0.41) . One interesting feature was that the CK efflux of subjects who had shown a large increase of CK after the 1 st Ex was not increased after the 2 nd Ex.
The initial exercise bout may have induced some damage to the muscle fibers or mem. bran. This damage would induce a process of repair in the damaged tissue, which in turn would adapt the muscle to the next stimulus. However, the subjects who showed a slight increase of CK after the 1 st Ex did not show this adaptation. Therefore an adaptive threshold for fiber or membrane damage may exist.

A study was conducted to investigate the relationship between energy systems and running performance, especially during the last spurt in an 800-m race. The subjects were separated into good 800-m runners (group A n=5: best record, 1′54″3±1.4) and a second group of slower 800-m runners (group B n=4: best record, 2′02″1±1.3) . Each group executed two types of running test (600m test and 800m test) . To simulate an 800-m race, the running speed up to 600m was set by means of a lamp pace maker system. The last spurt was running 200m at maximal voluntary running speed. Plasma lactate, plasma ammonia, serum glucose and blood pH were assayed at rest, after warming up, and 6 and 10min after the running test.
The following results were obtained:
1) The last spurt time of group A was significantly faster than that of group B (p<0.01) . 2) In group A, plasma lactate and plasma ammonia concentrations increased significantly during the last spurt (p<0.05) . In group B, however, plasma lactate and plasma ammonia concentrations before the last spurt (600m test values) were very close to the values after the last spurt (800m test values), 3) Last spurt times were significantly related to changes in plasma lactate concentration (r=-0.870, p<0.01) and O² debt (r=-0.799, p<0.01) during the last spurt.
These results suggest that running performance during the last spurt in an 800-m race depends on anaerobic energy ability, as reflected by plasma lactate, plasma ammonia and O² debt before the last spurt.