The present study was designed to investigate the effects of low altitude training on swimming performance with setting the same duration (3-wk) and the same level of altitude (2, 300m) . Eight male (Gm₁) swimmers aged 13 to 19 years and four male (Gm₂) and eight female (Gf₂) swimmers aged 13 to 18 years sent to Mexico City, and they conducted swimming work outs. All of them were top Japanese swimmers of various events. They repeated the swimming training twice a day continuously for four days with one day rest. Hemoglobin concentration (Hb), red blood cell count (RBC) and hematocrit (Hct) were determined before, during and after the altitude training several times. The values of Hb, RBC and Hct of all three groups increased significantly from before training to after training except Hb in Gm₁. On the other hand, these three variables did not necessarily increase during the altitude training. Gm₁ and Gf₂ tended to increase Hb and RBC during the training. As for swimming performance at sea level, the individual best swimming records were improved significantly in 200m events, but not in 100m events in Gm₁. Therefore, it may be concluded that 3-wk altitude (2, 300m) training possibly improve swimming performance in the events equal to or longer than 200m at sea level.

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The purpose of this study was to compare two methods of CO₂ rebreathing-equilibrium method (Collier, 1965) and extrapolation method (Defares, 1958) -for determining the mixed venous CO₂ pressure (PvCO₂) during exercise. Following a sitting rest for 5 min, five healthy males performed upright bicycle ergometer exercises with work rate of 100 and 150W for 5 min. During both at rest and in exercise, PvCO₂ was measured twice to evaluate the reproducibility of both methods. The equilibrium method was performed according to that by Jones & Campbell (1982) . In the extrapolation method, instead of using the graphical analysis described by Klauaen (1965), PvCO₂ was directly calculated by applying the modified exponential equation (Defares, 1958) . In the duplicate tests, coefficient of variation was lower while correlation coefficient was higher, with increasing work rate in both methods. It was noted that these tendencies were more pronounced in the extrapolation method than in the equilibrium method. It was concluded that in contrast to the results of Auchincloss et al. (1980), the extrapolation method was more reproducible than the equilibrium method.

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筋パワー発現時の筋の動態を検討する目的で本実験を行なった.被検者は, 最大底屈力の20, 40, 及び60%の荷重を最大努力で挙上する底屈動作を実施した.この時, 下腿の周径変化をラバーゲージにて記録した.
(1) 筋パワーは, 約60%MVCの負荷条件で最大となった.
(2) 筋パワーは, 荷重挙上開始初期の周径変化量と有意な関係があった.しかし荷重挙上速度が最大となる期間の周径変化量とは, 相関がなかった.
本実験で筋パワーが約60%MVC条件で最大となったのは, 腓腹筋の収縮特性に因るものと推察された.また筋パワー発現に, 荷重が慣性負荷となる前の抗重力的筋活動がとくに重要なことが示唆された.

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寒冷馴化 (CA) および累代寒冷飼育 (25G) ラットで骨格筋と褐色脂肪組織 (BAT) のトリグリセライド (TG) , リン脂質 (PL) 分画の脂肪酸 (FA) 組成を検討した.
1.骨格筋のTG: 多不飽和FA (PU) , 不飽和指数 (UI) がヒラメ筋で赤筋白筋より高かった.CAでは白筋の飽和FA (SA) が低下, PUが上昇した.25Gでは白筋でCAと同様の変化がみられた.またヒラメ筋では単不飽和FA (MU) , PUの上昇, SAの低下がみられた.
2.骨格筋のPL: TGに比較してSA, PUが高く, MUが低かった.CAでは赤筋でSAの上昇, PUの低下がみられた.白筋, ヒラメ筋では変化がみられなかった.25Gでは赤筋でCAと同方向の, しかし一層著しい変化が認められ.C20: 4, UIが低下, すなわちリン脂質の不飽和化の低下が示された.
3.BATのTG: CAではSAの上昇, MUの低下がみられた.25GではSAとPUの低下, MUの上昇がみられた.
4.BATのPL: CAではSA, PUの上昇, C20-4, AI, UIの上昇があり, 全体として不飽和化の促進がみられた.25GはAI, C: 24は上昇したが, UI, PUは変化しなかった.
以上の結果は寒冷馴化が熱産生に関係している組織のFA組成の変化をもたらすことを示すものであるが, その意義についてはさらに検討する必要があると考えられる.

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トレーニングされていない男子学生5名およびトレーニングされた3名の運動家について, 自転車エルゴメータによる60分間の運動負荷 (63～69%Vo₂max) 前後におけるPlasmaβ-endorphinとprolactinレベルが測定された.
β-endorphinは運動負荷前の14.9±0.7pg/ml (mean±S.E.) から, 負荷後には57.1±17.0Pg/mlへと有意な (p<0.05) 上昇を示した.
prolactinは負荷前9.4±0.7ng/mlから, 負荷後19.1±3.1ng/mlへと有意な (p<0.01) 上昇が認められた.
β-endorphinとprolactinの間には有意な正の相関関係がみられた (r=0.892; p<0.01; n=32) .トレーニング群は非トレーニング群にくらべ, 運動負荷後の血中β-endorphinおよびprolactinの上昇度は大きい傾向にあった.
結論として, 激しい運動負荷によるstressはβ-endorphinおよびprolactinの血中レベルを双方平行して上昇させ, トレーニング群では激運動に伴いβ-endorphinおよびprolactinの血中でのレベルを上昇大にする可能性がある.

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Ramp及びBallistic収縮が, 静脈還流や筋収縮後充血に及ぼす作用を検討する目的で本実験を行なった.被検者は, 足関節を20度伸展する底屈動作を, 1秒間又は最大努力で行なった.負荷量は等尺性最大底屈力の10, 20, 30及び40%とした.そして筋収縮時及び弛緩後の下腿囲変化をラバーゲージにて記録し, 筋収縮状態及び弛緩後の下腿囲低下や筋収縮後充血を検討した.
1) 筋弛緩後, 下腿囲は動作前値以下に一度低下し, ついで約7～9秒間, その値をこえて増大し, その後約30～40秒間で安静値に回復した.
2) 下腿容積の低下量は, Ramp収縮の場合, 負荷量の増加に従い増大した.一方Ballistic収縮時では, 一定の傾向がなかった.また増加量は, 両条件とも負荷量に依存して増加する傾向を示した.これらは, 全て1.0ml・100ml tissue^-1以下の容積変化であった.
3) 両収縮条件間で下腿容積の低下量及び増加量を比較すると, 低下量の場合, Ramp収縮の方で大きく, 増加量はBallistic収縮時で有意に大となった.
4) 筋弛緩後の下腿容積増加の最大速度 (Maximum Inflow Rate: MIR, ml・min^-1・100ml tissue^-1) と変化量 (低下量+増加量) との間に, 正の相関が得られた.
5) 底屈動作時の下腿囲増加量と筋弛緩後の下腿容積の各変化量との関連をみると, Ramp収縮時では, 下腿容積の増加量と変化量及びMIRと, Ballistic収縮時の場合, その増加量と変化量と下腿囲増加量との間に有意な正の相関が示された.
以上の結果から, Ramp収縮では筋のmilking actionが強く現われ, 一方Ballistic収縮の場合, 筋収縮後充血の増大をみることが示唆された.

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Six male and seven female children, aged five or six years, ran on the flat treadmill increasing running speeds every two minutes by 20 m/min till their subjective exhaustions. The first steps were started with the speeds of 80 or 100 m/min and the rest periods of 30 seconds were inserted between each successive step for the blood sampling. Expired airs for the determination of oxygen uptakes were collected during the last 30 seconds of every stage. Heart rates were recorded for each subject throughout the whole test session.
Two male and two female subjects were selected in order to determine their physical activity levels in the nursery school. Their heart rates were recorded from Monday to Saturday in a given week.
Analyses of physical activity patterns were tried by relating heart rate levels to circulorespiratory variables which were equivalent to 3 or 4 mmol/l blood lactate concentration (3m MLA or 4m MLA) .
By so doing, the following results were obtained:
1) Mean values of blood lactate concentrations observed immediately after the cessation of the last exhaustive steps were 5.16 m MLA for males and 4.70 m MLA for females.
2) Relative values of heart rate to 3 and 4 m MLA against maximal heart rate (% HRmax-3 m MLA and % HRmax-4 m MLA) were respectively 92.2% HRmax-3 m MLA and 97.5% HRmax-4m MLA for males and 94.9% HRmax-3 m MLA and 98.2% HRmax-4 m MLA for females.
The corresponding relative values of oxygen uptakes were 85.2% Vo₂max-3 m MLA and 94.3% Vo₂max-4 m MLA for males and 89.7% Vo₂max-3 m MLA and 96% Vo₂max-4 m MLA for females.
3) Mean values of heart rate recorded in the nursery through a given week except Sunday ranged from 89 to 114 beats/min for males and 106 to 126 beats/min for females. In the relative value of a heart rate against the heart rate equivalent to 4 m MLA, that is, HR 4 m MLA these values correspond to 44-57% HR 4 m MLA and 57-67% HR 4 m MLA respectively.
4) Accumulated duration time: Their hearts beat higher than 160 beats/min, except in the case of 800 m endurance run (only 0-4 and 0-6 minutes for males and 0-6 and 4-21 (touch of tachycardia) minutes for females) .
Percentages of accumulated duration time lower than 120 beats/min occupied 72-94% and 77-91% of 6 or 7-hour nursing time for males and 51-91% and 51-78% for females.
5) Absolute and relative values of mean heart rates in 800 m endurance run ranged from 183 beats/min (Net 83% HRmax, 90% HR 4 m MLA) to 199 beats/min (Net 98% HRmax, 104% HR 4 m MLA) for males and from 172 beats/min (Net 77% HRmax, 92% HR 4 m MLA) to 196 beats/min (Net 92% HRmax, 96% HR 4 m MLA), though the duration times were short.
6) Optimal intensity of work load was proposed to be the heart rate level of at least 190 beats/min for favourable development and/or improvement of the circulo-respiratory system in young children.

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Changes in myoproteins during development of rat skeletal muscle were investigated using two-dimensional gel electrophoresis. In M, soleus (SOL) which in adult, is composed predominantly of slow twitch fibers, fast type myosin light chains (fLC) were the major species and slow type light chains (sLC) were the minor species at birth. During development, the replacement rate of fLC to sLC sequentially occured so that LC patterns at 21 days postpartum were similar to adult where fLC were difficult to visualize. In contrast, M. extensor digitorum longus (EDL) always contained dominant fLC although sLC were found only for 5-9 days. LC 3 f became detectable at 5 days and gradually increased. In α-tropomyosin there were isozymes of fast and slow type based on difference in molecular weight, but not in β-tropo-myosin. Changes in isozymes of α-tropomyosin approximately corresponded with that in isozymes (fast and slow type) of LC in both EDL and SOL. During adult stage following birth, in EDL creatine kinase underwent a three-fold increase in molecular ratio to actin, whereas in SOL there was little change though increase took place transiently. These results suggest that with develoment many myoproteins change more dramatically in slow muscle than in fast muscle, and that transitions in LC isozymes and changes in distribution of histochemically typed muscle fibers may follow different time courses.

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Wistar系雄ラット (5週齢, 体重1009前後に, 12週間の食餌制限及び食餌制限下でトレッドミルを用いて運動負荷を実施し, それが各組織・器官のタンパク質代謝に如何なる影響を及ぼすかについて検討した.食餌制限は対照群の自由食餌量の2/3量とし, 運動の条件は, 毎分30m, 一日60分, 週6日とした.食餌制限の影響, 食餌制限下での運動の影響について, 次の様な知見を得た.
A.食餌制限の影響 (対照群との比較)
1.体重の減少
体重当りの組織・器官重量の増加
2.タンパク質含量の減少―腓腹筋, 肝臓及び腎臓
3.¹⁴C-amino acid mixtureの取り込みの抑制―脳, 腎臓
B.食餌制限下での運動の影響
1.対照群との比較
1) 体重の減少
体重当りの組織・器官重量の増加
2) タンパク質含量の減少―腓腹筋, 肝臓及び腎臓
3) 14C-amino acid mixtureの取り込みの抑制―脳, 腎臓
2.食餌制限下での安静群との比較
1) 体重の減少
体重当りの組織・器官重量の増加
2) タンパク質含量の減少―腓腹筋
長期間の食餌制限により, 脳以外のタンパク質含量の減少及び脳のタンパク質含量の維持が観察されたことから, 過酷な環境下における生命維持の合目的的な体内機構の存在が示唆された.また, この様な食餌制限下で, 運動を負荷すると, 腓腹筋のタンパク質含量が減少したことから, 特に骨格筋のタンパク質が運動のエネルギー源として動員されたものと推察した.
本研究の要旨は, 第42回日本体力医学会 (沖縄, 1987年10月) において発表した.

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10年間にわたる企業内健康・体力づくりプログラムが, 従業員の健康・体力に及ぼす効果を, 1, 657名の健康づくり検診受診者を対象に縦断的に観察した.加齢に伴って, 体重, 皮下脂肪厚の増加, 血圧の上昇はみられたものの, いわゆる肥満者の増加は認められず, また, 血圧異常を有する受診者の出現率も低値であった.また, 心電図異常出現率も増悪はみられず, 血液生化学検査上, 脂質代謝の改善が認められた.体力診断テストの結果についても, 改善したものが多く, 特に全身持久力の向上が認められた.これら医学的検査ならびに体力診断テストの結果から, 企業内健康・体力づくりプログラムの中高年齢従業員に対する体力医学的効果が示唆された.

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