The systolic time intervals (STI's) and the diastolic time (DT) as functions of the RR interval during exercise were proved to be described by cubic regression equations that converge to the origin of the coordinates. Using the equations, we compared I) the systolic time and DT of trained and untrained men, and II) examined the relations between parameters of STI's. I) Forty healthy male subjects aged 19-22 years old were divided into three groups, i, e., 8 long distance runners (group LD), 16 men with relatively high fitness (group A) and 16 men with relatively low fitness (group B) . They performed submaximal exercise test using a cycle ergometer for measuring the time of electromechanical systole (QS₂) and DT. After test, maximal exercise test was conducted to determine the maximal heart rate (HRmax) in each subject. Means±SD of the minimum QS₂ and the minimum DT of the 40 subjects predicted from the regression equations at the HRmax were 209.7±12.5 and 108.2±15.6 ms, their ratio being about 2: 1. The QS₂ was significantly shorter, whereas DT was longer in the group LD than in the groups A and B at the HR of more than 120 bpm. II) Ten healthy male subjects aged 19-22 years old performed submaximal exercise to clarify the relations between any two of QS₂, the left ventricular ejection time (LVET) and the preejection period (PEP) at the same HR: there were positive and negative significant correlations between QS₂ and LVET, and between LVET and PEP, respectively, at the HR of more than 100 bpm. These results reveal that, when the HR is increased in exercise, the left ventricular systolic time (QS₂) is shortened while the diastolic time is lengthened for the subjects trained as long distance runners. The shortening of the systolic time is mainly caused by shortening of LVET. The changes in the systolic and diastolic times suggest that contractility of cardiac muscle is enhanced during exercise of above moderate intensity after an extensive period of the aerobic training.

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本研究の目的は, 高い相対的強度の回復運動を負荷することによって持久性鍛練者の乳酸消長の特徴について検討することであった.対象は持久性鍛練者群である長距離選手 (Endurance-Train-ed Men; ET) 5名および対照群として比較的活発に運動している一般大学生 (Untrained Men; UT) 7名である.自転車エルゴメーターを用いて90%Vo₂maxに相当する3分間のMainExercise (ME) 後, 70%および40%Vo₂maxの二種類のRecovery Exercise (RE) で20分間実施した.各RE時の血中乳酸を測定し, 乳酸除去率Aおよび補正乳酸除去率Bを算出し, 以下の知見が得られた.
1) 70%REにおける10, 15, 20分目の血中乳酸値は, 町群の方がUT群に比べ有意に低かったが (P<0.05, P<0.01) , 40%REでは両群に有意な差が認められなかった.
2) 血中乳酸除去率Aは, 70%REにおけるET群 (0.2730±0.0920mmol・l^-1・min^-1) がUT群 (0.0520±0.1010mmol・l^-1・min^-1) に比べ有意に高かった (P<0.01) .40%REでは両群で有意な差は認められなかった.
3) 補正乳酸除去率Bは, 70%REでET群 (0.3770±0.08000mmol・l^-1・min^-1) の方がUT群 (0.1163±0.14416mmol・l^-1・min^-1) に比べ有意に高かった (P<0.01) .40%REでは両群に差が認められなかった.
4) 以上のことより, 本研究の持久性鍛練者が高い相対強度の回復運動でも高い乳酸除去率を示し, その値が回復運動ではもっとも効率の良い強度の乳酸除去率と変わらないほど高い乳酸除去率を示すことが指摘された.

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Experiments were performed on twelve young, healthy males. The subjects were asked to step in accordance with acoustic stimuli with a cyclic time of 1.2 s, while EMGs were recorded with surface bipolar electrodes from the vastus lateralis and medialis, semitendinosus, biceps femoris, tibialis anterior, and medial and lateral gastrocnemius muscles. An electrical stimulus consisting of 5 train pulses (duration : 1 ms, frequency : 300 Hz, 1.5 times perceptual threshold) was applied randomly to either the sural or posterior tibial nerve at the ankle joint during various stepping phases. In general, polyphasic reflex responses were elicited by the peripheral nerve stimulation. The reflex response of flexor muscles showed facilitation followed by inhibition, while that of extensor muscles showed inhibition followed by facilitation with either type of nerve stimulation. However in the case of sural nerve stimulation, inhibition followed by facilitation was observed during the early stance phase in the semitendinosus and biceps femoris muscles, which work as extensors during this phase. The effects of posterior tibial nerve stimulation on the femoral muscles during the stance phase were weak as than those of sural nerve stimulation. The amplitude of the reflex response changed depending on both the EMG activity of each muscle and the joint angle of the lower limb during stepping. It is suggested from these results that sensory inflow from the sole controls stepping, and that bifunctional muscles play an important role in the maintenance of equilibrium using peripheral inflow during stepping.

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A study was conducted to elucidate the changes in circulatory responses to sudden strenuous exercise (SSE) using beat-by-beat analysis of heart rate (HR), stroke volume (SV) and blood pressure (BP) . The effects of warming-up on these responses were also studied.
Six healthy male students volunteered for the study. A bicycle ergometer was prepared for SSE. The intensity and duration of SSE were 100% VO₂max and 1 min, respectively. Warming-up of 80% VO₂max for 5 min followed by SSE. The interval between SSE and warming-up varied from 5 to 30 min. A control experiment was also performed without warming-up.
The main results obtained were as follows :
1) BP decreased in the initial stage of SSE, followed by a steep increase. This temporary drop in BP was prevented by warming-up. This might contribute to the prevention of myocardial ischemia which is occasionally observed in the initial stage of SSE without warming-up.
2) Time constants of HR and SV during SSE were shortened by warming-up with long intervals, while the time constant of BP was shortened when the interval was short.
3) The recovery response of each parameter was accelerated by warming-up, but the effect of warming-up had almost disappeared after a 30 min interval.
These results suggest the following conclusions :
Warming-up accelerates the up-stroke and recovery of circulatory responses to SSE, but these effects of warming-up are strongly influenced by interval time. In particular, the effect of recovery acceleration is almost abolished by a 30 min interval.

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A study was performed to investigate the effects of exercise and Spirulina platensis (SPL) intake on the hapten specific immune response of growing mice.
Male BALB/C mice aged five weeks were divided into 6 groups : Group A was a control group given a normal diet ; group B, sedentary with a normal diet ; group C, exercise with a normal diet ; group D, control with SPL diet ; group E, sedentary with a SPL diet ; group F, exercise with a SPL diet. The mice in groups C and F were trained by swimming for about 30 min 4 times a week for 5 weeks. The SPL diet was a mixture of SPL (20%) and the normal diet (80%) . At 4 weeks after the experiment, the mice belonging to groups B, C, E and F were sensitized with 1% toluene-2, 4-diisocyanate (TDI) . Five days after sensitization, TDI was painted on the ears of the mice, and delayed type hypersensitivity (DTH) was evaluated by measuring the ear thickness at 24 h later as an index. After this evaluation, the body weights of the mice, the weights of the thymus and spleen, and serum TDI-specific IgG antibody levels as an index of humoral immunity, were measured.
In the mormal diet groups, the highest DTH reaction was shown in the exercise group, followed by the sedentary group. On the other hand, the DTH reactions in the SPL diet groups were significantly suppressed in both the sedentary and exercise groups. However, a slightly higher DTH reaction was shown in the exercise group than in the sedentary group. Body weights of mice in the exercise groups receiving both the normal and SPL diets were suppressed in comparison with the control and sedentary groups. Although increased spleen weights were shown in all the sensitized groups, thymus weights in the 6 groups were not changed. TDI-specific IgG antibody levels were also not changed in any of the TDI sensitized groups.
From these results, the SPL diet seemed to effectively suppress the DTH reaction, and might be effective for treatment of various types of contact hypersensitivity which are currently the focus of clinical attention.

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A portable device for long-term monitoring of oxygen uptake without discomfort has been developed based on a flow-through principle. The oxygen content of the exhaust gas was kept constant by a servo-controlled blower, so that the flow rate was essentially proportional to the oxygen uptake. This system was evaluated by both a bench test and in exercising human subjects. The limiting current-type oxygen sensor used this portable device produced results which were in good agreement those obtained using a zirconia oxygen sensor (r= 0.999), and stable values were obtained for at least 15 h. The response time for a stepped oxygen change was 4 s. The air flow rate produced by the blower was proportional to the supplied voltage. The results using a time-of-flight flowmeter were highly correlated with those for a hot-wire anemometer (r=0, 999) . The oxygen uptake of exercising human subjects measured with this portable device showed good agreement with that obtained by a conventional oxygen monitor (r=0.973 for cycle ergometer, r=0, 932 for treadmill) . This portable device was able to measure oxygen uptake in subjects during daily activities, and also while driving a car, without disturbance.

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同一強度の労働を日常行なっている工場従業員を対象にし, ハンドボール選手群と非運動対照群とに分けて血清脂質の変動について比較検討した.
ハンドボール選手群においてはTGの減少, HDL-Chの上昇, 亜分画ではHDL₂-Chの上昇がみられ, アポ蛋白ではアポA-Iが有意に高値を示した.またLCAT活性もハンドボール選手群で高かった.さらに動脈硬化の指標としてのアポB/アポA-I比をみるとハンドボール選手群でより低値を示した.以上, ハンドボール選手では, 血清脂質の中でいわゆる抗動脈硬化作用を有するとされるリボ蛋白画分とアポ蛋白画分が高値を示していることが確認された.また動脈硬化指数の低下からも長期にわたるハンドボール運動が動脈硬化性疾患の予防, 発症率の減少に結びつく効果を持つと考えられた.

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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.

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大学陸上投擲選手を対象にし, 日頃のトレーニング期における蛋白質摂取量 (B群: 1.5g・kg^-1・d^-1) とその摂取量よりも蛋白質を増加した場合 (A群: 2.1g・kg^-1・d^-1) とにおける62日間の栄養管理下の蛋白質摂取量の違いが, 身体組成と身体諸機能へ及ぼす効果を検討した.その結果は以下のようである.
1) 62日間の平均1日当りのエネルギー摂取量はA群3824kcal, B群は3441kcalであり, 蛋白質摂取量はA群2.0g・kg^-1., B群は1.5g・kg^-1となり, ビタミン・ミネラル類はRDAを十分に充足した.
2) 62日間の献立食摂取により両群の体重, %fat, Fat, LBWはいずれも有意な変化を示さなかった.また, MRIによる大腿部および腹部のそれぞれ脂肪と脂肪以外の断面積についても両群ともそれぞれ有意な変化はなかった.
3) 血液成分では, 両群とも有意に変化した項目があったが, いずれも正常範囲内の変化であり, 両群とも貧血症状はみられなかった.また, 尿中尿素窒素量は両群とも有意な変化を示さなかった.
4) 最大等尺性収縮による握力, 腕伸展九腕屈曲力, 脚伸展力, 脚屈曲力は両群とも有意な変化を示さなかった.
以上のように, 本研究の陸上投擲選手がトレーニング期に蛋白質の摂取量を, 日頃摂取している1.5g・kg^-1・d^-1から2.0g・kg^-1・d^-1へと62日間にわたって増加させ摂取したのであったが, LBWや筋力は増加しなかった.このことから, わが国でスポーツ競技者の蛋白質所要量として推奨されている2.0g・kg^-1・d^-1は, 少なくとも本研究の陸上競技投擲選手のLBWと筋力の増加には有効ではないことが明らかとなった.また, 貧血を生じさせない蛋白質摂取量は2.0g・kg^-1・d^-1以下でも十分であることがわかった.

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