In an attempt to study the effect of a moderate work load on the concentration of serum erythropoietin and hemoglobin in young women, 8 female university students with a high hemoglobin content (group H), 7 female university students with a low hemoglobin content (group L) and 7 female university students with a tendency to be anemic (group A) were subjected to moderate work for 7 successive days in summer.
Each subject pedalled at a constant work load of 1.25kp at a cycling rate of 50rpm for 60min every day. Blood samples were drawn from the cubital vein under basal conditions on the day before training, the fourth day of training and the day after the training period. The results obtained were as follows; Group H showed a significantly higher erythropoietin concentration before training than groups L and A. The concentration of erythropoietin in group H decreased slightly during the training period, whereas those in groups L and A increased, although the differences were not statistically significant.
The concentration of serum iron in group H was significantly higher than that in group L before training. The former decreased significantly during the training period, whereas the latter was maintained at a lower level. The differences in blood constituents found among the three groups before training lessened after one week's moderate exercise.
The increase in Hb concentration in the subjects in groups L and A after training might have been induced by the augmented secretion of erythropoietin due to training for 7 successive days.

View full abstract

We studied the relationship between bone mineral density (BMD) and history of habitual exercise in a group of university students comprising 41 athletes (27 males and 14 females) and 39 non-athletes (24 males and 15 females), ranging in age from 18 to 28 years. Their athletic history during elementray, junior and senior high schools was surveyed. Subjects who had engaged in athletic activities more than 3 days/week for more than two years at each school level were classified as a former physically active group, whereas the others were classified as controls. The BMD of the femur (femoral neck, Ward's triangle, trochanteric region) and vertebrae (L2-4) was ieasured using dual-photon absorptiometry with a ¹⁵³Gd source. The following results were obtained: 1) University athletes showed significantly higher BMD of the femur and L2-4 than non-athletes. 2) No significant difference was found for either sex between the physically active group on elementary school days and the control group with regard to BMD of the femur and L2-4. 3) The BMD of the femoral neck and trochanteric region in the male physically active group on junior high school days was significantly higher than that in the control group. The BMD of the femoral neck in the female physically active group on junior high school days was significantly higher than that in the control group. 4) The BMD of the femur and L2-4 in the female physically active group on senior high school days was significantly higher than that in the control group, whereas no difference was found between these two groups for males. These results suggest that regular exercise during puberty is effective for increasing BMD, especially in females. The finding that increased BMD in association with physical activity on senior high school days was observed only in females may be due to the synergistic effect of estrogen and exercise.

View full abstract

Twenty-eight skinfold measurements taken from 223 Japanese females, ranging in age from 16 to 26 years, were analyzed to study the anatomical distribution and total mass of subcutaneous fat on the trunk and limbs. The measured thicknesses of subcutaneous fat varied on average from 5.8 to 22.7mm. The thicker skinfolds were obtained from the abdomen, waist, and thigh. The calculated total mass of subcutaneous fat on the trunk and limbs was 13.7±3.78kg, corresponding to 23.3±3.87% of total body weight. The slopes of the regression lines between the total mass of subcutaneous fat and skinfolds ranged from 0.22 to 2.19. The slopes obtained for the abdomen, greater trochanter and thigh were steeper than those for other regions. It is suggested that the Japanese females have greater skinfolds at the abdomen, waist and thigh than at other regions, and that differences exist among various regions in subcutaneous fat accumulation.

View full abstract

A study was conducted to investigate using ³¹P NMR the relationship between the total excess volume of CO₂ output (CO₂ excess) due to bicarbonate buffering of lactic acid produced in exercise and the decrease of intracellular pH during incremental exercise. Five sprinters and 5 joggers performed incremental exercise to exhaustion on an bicycle ergometer. The values of CO₂ excess and CO₂ excess per body weight (CO₂ excess/W) were not different between the sprinters (2388±659ml, 36.7±8.5 ml·kg^-1) and the joggers (2275±278ml, 40.0±6, 3ml·kg^-1) . Below the ventilatory threshold (VT), from VT to the respiratory compensation point (RCP), and above RCP, the V_od2-V_co2 slopes were not different between the sprinters and the joggers, respectively (0.95±0.05 vs 0.95±0.06, 1.21±0.11 vs 1.30±0.14, 1.69±0.24 vs 1.76±0.18) . However, the joggers showed significantly higher CO₂ excess/W per blood lactate accumulation (ΔLa) in exercise (CO₂ excess/W/ΔLa, 5.34±0.32ml·kg^-1·mmol^-1·l^-1) than the sprinters (4.50±0.14ml·kg^-1·mmol^-1·l^-1) . The decrement of intracellular pH during incremental exercise showed a tendency to be smaller in joggers (0.63±0.18 pH unit) than in sprinters (0.83±0.10 pH unit), although there was no significant difference between the two groups. The values of CO₂ excess/W/ΔLa were correlated with the decrease of intracellular pH (r=-0.792, p<0.01) . It is suggested that CO₂ excess/W/ΔLa reflects the efficiency of the bicarbonate buffering system, and could be an important factor influencing the decrease of intracellular pH due to lactate production.

View full abstract

Principal component analysis was used to estimate the physical fitness age (PFA) of middle-aged and elderly men from eight physical fitness variables. The subjects were 184 Japanese men, aged 20 to 75 years, who were recruited in a series of physical fitness tests including oxygen uptake corresponding to lactate threshold (Vo₂@LT) and maximal oxygen uptake (Vo₂max) . The subjects were categorized into three groups : those (n=134) considered apparently healthy, those (n=35) employed as a cross-validation sample, and 15 patients with coronary heart disease (CHD) . The equation developed for estimation of PFA in healthy individuals (n=134) was PFA=-15.3 PFS+48.0+Z, PFS=0.021 X₁+0.037 X₂+0.020 X₃+0.024 X₄+0.017 X₅+0.017 X₆+0.008 X₇+0.016 X₈-4.92, Z =0.12 Age-5.8; where PFS=physical fitness score, X₁=V_o2max (ml/kg/min), X₂=Vo₂@LT (ml/kg/min), X₃=grip strength (kg), X₄=side step (reps/20s), X₅=trunk extension (cm), X₆=trunk flexion (cm), X₇=foot balance with eyes closed (s), and X₈=vertical jump (cm) . Analyses of the data revealed that healthy individuals had PFAs (47.7±17.5yr) similar to their chronological ages (CA: 48.0±15.3yr) . In the cross-validation sample, it was confirmed that no difference existed between PFA (51.5±13.8yr) and CA (52.1±11.8yr) . CHD patients, however, had PFAs approximately 15 years older than their CAs (57.7±11.5vs. 72.2±12.3yr) . Since independent variables of the above equation consisted of various physical fitness elements, we defined the score as an index of “physical fitness age”. The importance and usefulness of PFA were discussed in more detail.

View full abstract

The effects of physical training and acute exercise (mechanical treadmill running) on the level of lipid peroxide in skeletal muscle of rats fed vitamin E-deficient or -supplemented diet were studied.
1. The level of lipid peroxide in skeletal muscle of untrained rats was significantly increased immediately after acute exercise (p<0.05), but physical training suppressed of increase in the level of lipid peroxide and an increase in the activity of superoxide dismutase. These findings were strongly shown in soleus muscle among the muscles examined in this experiment.
2. The level of lipid peroxide in soleus muscle was significantly increased in vitamin Edeficient rats compared to that of control rats (p<0.05) .
Conversely, the level of lipid peroxide in muscles was significantly depressed by feeding vitamin E -supplemented diet (p<0.05) .
3. Dietary vitamin E -supplementation did result in a increase in superoxide dismutase activity of muscle.

View full abstract

The effects of stretching, sport massage, light exercise (80% of the subjects' anaerobic threshold), and hot pack on the recoveries of work capacity and blood lactate (La) after strenuous exercise were compared with the resting recovery conditions. In each experiment for the four recovery strategies, twelve male physical education students participated as subjects. The subjects performed 5-s maximal effort cycle ergometer exercise bouts, repeated 8 times with 20-s rests (W 1) . A 33-min rest period was given after W 1, and then the same exercise as W 1 was performed again (W 2) . During the rest period (from 9 to 19min after W 1), one of the recovery strategies was practiced for 10min. The subjects also participated in a control experiment (rest recovery) on another day. Blood samples were taken from the earlobe to determine La. The rate of work capacity recovery was significantly higher than the control when stretching was performed, but no significant difference was observed in the recovery rate of La. The same tendency was also observed in the case of sport massage. In the case of light exercise, on the other hand, the recovery rate of La was significantly higher than the control, whereas the recovery rate of work capacity was not significantly different. Many of the subjects complained that the intensity of light exercise was too hard. No significant differences were found in the recovery rates of both work capacity and La by application of a hot pack. These results suggest that stretching and sport massage are effective for accelerating recovery of work capacity. Light exercise was not effective in this study. However, considering previous investigations which showed light exercise to be effective, it might be effective if an abequate work intensity is given. A hot pack is suggested not to be effective. No significant correlation was observed between the recovery rate of La and that of work capacity. Thus it seems that the recovery of work capacity is regulated by factors other than La.

View full abstract