A study was conducted to clarify the exercise intensity and metabolic condition during a free routine of synchronized swimming with respect to heart rate (HR), blood lactate concentration (La) and the rate of perceived exertion (RPE) . Six well trained female synchronized swimmers participated as subjects. HR during the free routine was measured continuously. La and RPE during the free routine were measured intermittently from the start to end of each stage. Maximum heart rate (swimmingHRmax : S-HRmax) was determined by measurement of maximum oxygen uptake using a swimming flume. Peak blood lactate concentration (Peak La) was measured after the maximum front crawl stroke of 100 m. The average values and S. D. of S-HRmax and Peak La were 180.0±3.8 beats · min^-1 and 9.6 ± 1.0 mmol · 1^-1, respectively. Average values, S. D. and ranges of HR and %S-HRmax during the free routine were 137.6±25.5 (60-180) beats · min^-1 and 76.5± 14.3 (34.5-96.8) %, respectively. HR during the free routine showed a decrease in the breath-holding phase. Average values and S. D. of La, %Peak La and RPE at the fourth stage were 5.4±1.2mmol·1^-1, 57.0±17.2% and 17.7±0.8, respectively. La, %Peak La and RPE at the fourth stage were significantly higher than those at the other stages, and La, %Peak La and RPE at the third stage were significantly higher than those at the second stage. These results suggested that the overall intensity of the free routine was moderate, but that part of the free routine included high-intensity activity and the percentage of anaerobic metabolism during the free routine increased in the final stages

A study was performed to examine the effect of plasma lactate concentration on intravascular hemolysis during exercise. Seven men performed maximal and submaximal exercise on a cycle ergometer. The maximal exercise was performed as a graded exercise until exhaustion. The mean performance time of the maximal exercise was 15 min and 4 s. The submaximal exercise was performed for 30 min at 50% HRmax. Blood samples were obtained before, immediately after, and one hour after exercise. Plasma lactate concentration, hematocrit (Ht), and serum haptoglobin concentration (Hp) were measured. Hp was corrected by Ht for hemoconcentration and expressed as HpC. Plasma lactate concentration was elevated significantly (p<0.05) immediately after maximal exercise, and returned to the baseline values one hour after exercise, whereas plasma lactate concentration did not change after submaximal exercise. Hp and HpC did not change even after maximal exercise. These results suggest that the elevation in plasma lactate concentration may not affect intravascular hemolysis during exercise.

The purpose of this study was to determine the physiological responses, stroke rate and stroke length of front crawl leg kick and arm stroke of age-group and college swimmers and to elucidate the characteristics of male age-group swimmers, which have not been highlighted adequately. The subjects were ten 11.8-to 12.4-year-old well-trained male elementary school swimmers (group E) and nine 20.1-to 21.1-year-old well-trained male college swimmers (group C) . All the subjects were categorized into similar swimming levels for their ages. All the experiments were performed in a swimming flume (AQUAGYM made by IHI) . The water velocities during leg kicking and arm stroking were 60 and 70%, respectively, of the maximal velocity at maximal oxygen uptake (Vmax) . The oxygen uptake (VO₂), heart rate (HR), pulmonary ventilation (V_E), tidal volume (TV), respiratory rate (RR) and blood lactate (BL) level of each group were significantly higher during leg kicking than arm stroking at both velocities. VO2, V_E; and TV were significantly higher in group C than group E during leg kicking and arm stroking at both velocities, but HR, RR and BL did not differ significantly. The leg kick to arm stroke VO₂ ratio at 70% Vmax was significantly higher in group E than group C. The stroke rate at the same velocity was significantly lower and the stroke length was significantly higher in group C than group E, but the kick rate and length did not differ significantly. VO₂·SR^-1 and VO₂ KR^-1 at both velocities were significantly higher in group C than group E. VO₂ Wt^-1 SR^-1 at 70% Vmax was significantly higher in group C than group E, but VO₂ Wt^-1 KR^-1 at both velocities was significantly lower in group C than group E. These results clarified the differences between group E and group C, which must be considered carefully when designing a training program for age-group swimmers.

Structural and mechanical adaptations of the femur and tibia to jump and run training were investigated in female Fischer 344 rats. Rats aged 4 weeks were trained for 8 weeks after 1 week of stabilization. In experiment A, the forced run-trained (speed : 30 m/min, duration: 1 h/day) group was compared with the control group. In experiment B, voluntary run and jump-trained (height : 40 cm, 100 times/day) groups were compared with the control group. The limb bones of the jump-trained group had greater cross-sectional areas and greater maximum load in a fracture test than the limb bones of the control group, but there was no significant difference in bone length between the jump-trained group and the controls. The bone adaptations to forced running and voluntary running were similar. The limb bones of both run groups were longer than those of each control group. The cross-sectional areas and the maximum load in the run-trained groups were greater than those in each control group but less than those in the jump-trained group. The present results indicate that bone adaptations to jump training and run training differ and that jump training is more effective for building stronger bones.

Four 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.

The purpose of this study was to compare blood lactate concentration, lactate threshold (LT) and onset of blood lactate accumulation (OBLA) during an incremental bicycle exercise under a hot dry environment with those during the same workload under a thermoneutral environment. Eight unacclimated men performed an incremental test to exhaustion on a cycle ergometer during which the work rate was increased by 30 W every three minutes under thermoneutral (25°C) and hot dry (40°C) environmental conditions. Oxygen consumption (VO₂) -pulmonary ventilation (VE), gas exchange measures and earlobe blood samples for lactate analysis were obtained every minute during the test. LT (p<0.05) and OBLA (p<0.01) occurred at significantly lower VO₂ under the hot environment than those under the thermoneutral environment. Additionally blood lactate concentration was significantly higher (p<0.05) at each measurement period under the hot environment compared with that under the ther-moneutral environment. The correlation between LT and ventilatory threshold (VT) was not statistically significant under the thermoneutral (r=0.20) and hot dry (r=0.60) environments, These findings demonstrate that the hot dry environment may increase blood lactate concentration more and causes a leftward shift of LT and OBLA. Since blood lactate accumulation during incremental exercise is not considered to be the only factor which mediates VE, VT does not always accurately predict LT.

The most characteristic feature of the triathlon is integration of the three endurance activities including of swimming, cycling and running, into a continuous task. So, it is necessary to identify the cardiorespiratory responses during the triathlon to develop a beneficial training program. Twelve male triathletes conducted a simulated triathlon test in a laboratory. This test consisted of continuous swimming, cycling and running using a flumepool, a bicycle ergometer and a treadmill, respectively. The exercise intensity and duration were 60% of maximal oxygen uptake during swimming, cycling and running for 30, 75 and 45 min, respectively. The results demonstrated that the residual effects of the prior exercise stage were observed during the latter exercise stage : The prior swimming stage produced an increment of oxygen uptake and heart rate during the cycling stage ; Prior swimming and cycling stages increased oxygen uptake, minute ventilation, heart rate and ventilatory equivalent to those during the running stage. These results suggest that the residual effects of the preceding exercise decreased the mechanical and respiratory efficiency by increasing the physiological demands of conducting the subsequent exercise. Therefore, triathletes are recommended to train themselves in a continuous task rather than separately.

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.

Energy expenditure during sport activities has been determined traditionally by the Douglas Bag Method and the Motion Time Study. However, those two methods do not yield accurate values when used in long continuous and/or vigorous physical activities. This study, therefore, measured oxygen uptake by means of a portable device “Oxylog”, and determined the energy expenditure of many sport activities. The experiments were carried out with 13 untrained male subjects (UTS), and 30 trained male subjects (TS) . The 30 trained men consited of ten tennis players, ten badminton players and ten basketball players. UTS played one set of doubles (tennis), one set of singles (badminton), two sets of singles (table tennis), two games (bowling) and jogged 10 minutes, But TS played only their major sports : one set of doubles (tennis), one set of singles (badminton) and two 20-minute halves (basketball) . The results were 0.172±0.017kcal⋅kg^-1⋅min^-1 for jogging (UTS), 0.146±0.028kcal⋅kg^-1⋅min^-1 for badminton (TS), 0.133±0.021kcal⋅kg^-1⋅min^-1 for basketball (TS), 0.130±0.018kcal⋅kg^-1⋅min^-1 for badminton (UTS), 0.102±0.016kcal⋅kg^-1⋅min^-1 for tennis (TS), 0.096±0.014kcal⋅kg^-1⋅min^-1 for tennis (UTS), 0.089±0.019kcal⋅kg^-1⋅min^-1 for table tennis (UTS), and 0.055±0.009kcal⋅kg^-1⋅min^-1 for bowling (UTS) . In comparison with UTS, TS exhibited higher values in tennis and badminton. This is considered to result from TS's better training. This result indicates that energy expenditure in playing sports activities depends on the level of player's ability. The method employed in of this study is believed to be the best choice at present. Many other sport activities must be reexamined in detail using this method.

Bone mineral content (BMC), fat weight (FAT) and lean tissue weight (LTW) were determined by dual-energy X-ray absorptiometry (DEXA) in 20 young adults of both sexes who were performing habitual exercise. From these data, body weight, lean body weight (LBW) and the percentage of BMC relative to LBW (BMC%LBW) were obtained. First, body density based on a two-component model (D₂) was calculated using the values of FAT and LBW of the subjects and the fat and lean densities of the Reference Body, Then percentage body fat (%Fat₂) was calculated using the formula of Brozek et al. The body density for a three-component model (D₃) was then determined from the values of FAT, BMC and LTW of the subjects, and the fat, bone mineral and lean tissue densities of the Reference Body. Percentage body fat (%Fat₃) was also calculated in the same manner as %Fat₂. Analysis of the data indicated that (1) females had higher values of BMC%LBW than males, and that (2) subjects whose %Fat₂ exceeded %Fat₃ by more than 1% were exclusively females whose BMC%LBW values were more than 6.1%. In contrast, those whose %Fat₂ was lower than %Fat₃ by less than -1% were exclusively males who had BMC%LBW values less than 5.2%. It is concluded that male subjects develop their muscles more than their bones with habitual exercise, which results in a lower BMC%LBW value than in females, and that for those with BMC%LBW values exceeding 6.1% (females) or less than 5.2% (males), %Fat calculation from body density using the formula of Brozek et a1. will produce an error of more than 1% if BMC%LBW is not considered.