The repeatability of the mechanomyogram (MMG) must be carefully determined before the signal can be generally used as a reliable tool in the fields such as physical fitness, sports and rehabilitation. In the present investigation, both the between-trial and between-day repeatability of the MMG was examined in the time and frequency domain and was compared with that of the more established electromyogram (EMG) . Isometric contraction trials of the biceps brachii muscles at different force levels of 10% to 90% MVC were held until a force plateau lasting 5 s was completed. The testing session consisting of 9 submaximal trials was repeated 6 times on the same day for estimation of the variation between trials. The same testing session was also performed 8 times over 3 weeks with a 2-day rest interval to examine the day-to-day variation. The coefficient of variation (CV) between-trials as well as between-days of the root mean squared (rms) MMG, mean frequency and median frequency did not demonstrate any significant differences among the force levels. The combined CV of the rms MMG over all the force levels was approximately 9 % between trials and 22% between days. The mean frequency and the median frequency presented the CV between-trials and between-days of approximately 6% and 10%, respectively. The different CV between the time and frequency domain parameters of the MMG may result from different contributing factors in the motor unit activation pattern. The results of this study suggest that the repeatability of the time domain parameter of the MMG is similar to that of the more established EMG, whereas the frequency parameters are somewhat less repeatable than those of the EMG.

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The purpose of this study was to compare the influence of prolonged continuous (CON) and intermittent (INT) exercises on metabolic and hormonal responses in 8 male college students (age ; 23.0±0.5 yr, weight; 67.7±1.5 kg, VO₂max ; 2.8±0.1 L/min, mean±SE) . Both trials consisted of two 40 min cycling bouts divided by a 5-min rest period. The intensity of INT was alternated every 4 min at low intensity (25% VO₂max) and high intensity (75% VO₂max), whereas the intensity of CON was maintained at 50% VO₂max. Blood samples were collected before, and after 40 and 80 min of exercise, to determine blood lactate, serum glucose, FFA, insulin, plasma adrenaline and noradre-naline. Perceived exertion (RPE) was assessed at 40 and 80 min of exercise using the Borg scale. Although the changes in the concentration of plasma noradrenaline and serum insulin from basal values were similar in INT and CON, the degree of increase in plasma adrenaline during INT was significantly smaller than that during CON (90.5±16.6 vs. 152.8±27.0 pg/ml, p<0.05, after 80 min of exercise) . There was no difference in the change in the serum glucose level between the two trials. However, serum FFA in INT was significantly smaller than that in CON after 40 min (0.28±0.06 vs. 0.10±0.04 mEq/l, p<0.05) and 80 min (0.54±0.08 vs. 0.33±0.07 mEq/l, p<0.05) of exercise. RPE did not differ between the trials. These data indicate that even if performed total work and exercise duration are the same, metabolic and hormonal responses during prolonged intermittent exercise differ from those during continuous exercise.

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本研究では, 減量プログラムの成果に季節差がみらるかどうかを検証するために, 日本の成人肥満女性95名を対象に運動と食事指導からなる減量プログラムを実施し, 身体計測値および身体組成と有酸素性能力の変化を検討した.得られた主な結果は次の通りである.
1.W群はS群と比較して, 身体組成は望ましい変化であった.とくにFFMの増加はW群で有意に大きかった.
2.VO₂maxの変化の大きさに両群間で差異はなかったが, VO₂LTの変化はS群で有意に大きかった.
3.総摂取エネルギーはS群で有意に減少し, 3大栄養素別では糖質が有意に減少した.しかし, PFC比でみれば両群に差異はなかった.
以上より, W群はS群に比べて身体組成に望ましい変化を示したといえ, その変化にはエネルギー摂取量の差異および寒冷環境下での脂肪組織の活性の違いが影響していると推察できる.FFMの増加と有酸素性能力の向上との関連については検討の余地が残るが, 本研究の結果は減量プログラム実施にとって冬季が有利であることを示唆している.
本研究の要旨の一部は, 第2回European College of Sports Science (於: コペンハーゲン) において報告した.
本研究の一部は筑波大学先端学際領域研究 (TARA) センター (田中プロジェクト) の援助を受けて行なったものである.

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The purpose of this study is to obtain more information about the occurrence of sports injury and through this to prevent injury in handball players.
Aquestionnaire was delivered to Japanese and Korean company handball players totaling 244 women (8 Japanese teams, 136 women and 7 Korean teames, 108 women), during the period from December, 1996 through March, 1997. The return rate was 88.9%. Injury rate in Korean teams was 73.2% and 71.7% in Japanese teams ; no statistical differences were found among these two countries. The injury rate was high on ankle joint, knee joint and lumbar in that order. Korean teams presented higher occurrence of jumper's knee and stress fracture.

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本研究では, 活動筋の酸素動態を筋への酸素供給と筋での酸素消費の観点から筋別に評価することにより, 運動強度の変化に対して肺胞での酸素摂取量が変化する過程において, 協働筋の酸素動態がどのように変化するかを明らかにすることを目的とした.被検者は年齢21～22歳の体育専攻の女子大学生7名であった.運動は椅座位姿勢での膝関節伸展運動とし, 0Wから2分毎に休息を挟みながら5Wずつ負荷を増加させるプロトコールでの運動を行わせた.肺胞での酸素摂取量は10秒間のmixing chamber法で測定した.外側広筋と大腿直筋を被検筋とし, 筋の酸素動態を近赤外分光法を用いて評価し, さらに表面筋電図を記録した.
その結果, 膝伸展運動の強度の増加に対して, 50%Vo_2peak以下の比較的低い運動強度では外側広筋と大腿直筋における酸素の供給と消費のバランスには顕著な変化がみられなかった.しかし, さらに強度が高くなると筋での酸素の供給と消費のバランスに変化がみられ, 大腿直筋の方が外側広筋と比較してより低い強度で脱酸素化が亢進し始めた.このことから, 膝伸展運動の強度の増加に対して肺胞での酸素摂取量が変化する過程において, 協働筋である外側広筋と大腿直筋での酸素の供給と消費のバランスは, 運動強度に対して筋間で異なった変化を示すことが明らかになった.

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本研究では400m走後半の筋疲労状態での疾走能力と体力的要因との関係を検討した.15名のランナー (400m走記録48.90±1.18s) を対象に, 80m走, 400m走のビデオ撮影および酸素摂取能力, 酸素負債能力, 最大筋パワーおよび筋持久性などの体力的要因の測定を行った.ビデオ分析により80m走中の全力疾走速度 (50m付近の疾走における走速度) , 筋疲労時疾走速度 (400m走中の360m付近の疾走における走速度) , %Max.Speed (全力疾走速度に対する筋疲労時疾走速度の割合) を算出した.
主な結果は次の通りである.
1) %Max.Speedは, 全力疾走速度と有意な負の相関関係にあったことから, 高い疾走速度を出す能力と, 筋疲労時において全力疾走時により近い速度で走ることのできる能力は相反すると考えられる.
2) 筋疲労時疾走速度は, 股関節伸展・屈曲運動の持久性指標との間に有意な正の相関関係が認められた.
3) 酸素負債量は, 400m走平均走速度との間に有意な相関関係が認められたが, 筋疲労時疾走速度との間には有意な関係が認められなかった.
4) %Max.Speedと股関節屈曲・伸展筋持久性, 膝関節屈曲持久性および最大酸素摂取量との間に有意な正の相関関係が認められた.

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A study was conducted to clarify the occurrence of injuries among Japanese and Korean handball players, their present condition, and the response to prescribed treatments. It was also ascertained whether players, after receiving proper treatment, were less susceptible to injury sequelae. A questionnaire was delivered to Japanese and Korean company handball players totaling 244 women (8 Japanese teams, 136 women ; 7 Korean teams, 108 women), during the period from December 1996 through March 1997.
The rate of injuries and the treatment situation during and after the period when the injury was sustained, and the occurrence of sequelae in the lower limbs after the player had joined the team, were examined, and a comparison between the two countries was made. The return rate was 88.9%.
1. The emergency treatment rate after injury was similar in the twe countries. However, Japanese players usually used taping and cooling, whereas Korea players used heat treatment. 2. Both Japanese and Korean players' injuries were diagnosed at hospital, although Koreans also went to bonesetters. 3. Japanese players resumed playing upon receiving their doctors' consent, whereas some Korean players were forced to resume playing before fully recovering ; there was a significant difference between the two countries. 4. Many players in both countries, resumed playing even though they felt pain in daily life. 5. Players who had undergone cooling treatment immediately after the injury, and who resumed activities upon their doctors' consent, and only after the pain had disappeared during daily life, had a lower incidence of sequelae.

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本研究の目的は, 磁気共鳴分光法 (³¹P-MRS) と近赤外分光法 (NIRS) とを用いて, 等尺性運動負荷時に見られる局所的な筋疲労, 特に運動強度の違いが筋疲労の程度や筋持久力 (持続時間) に及ぼす影響を細胞内の代謝および酸素動態の面から観察し, さらに各負荷強度の持続時間.どの関連について検討を加え, 以下の結果を得た.
1) 各相対強度での持続時間は50%MVCで95.3±13.6秒, 30%MVCで209±41.9秒であり, また低強度の10%MVCでは963±236秒と, 50%MVC時の10倍であった.
2) 運動中の各測定項目の変動をみると, 運動開始時においてPCrの低下及びPi (H₂PO₄-) の上昇が見られた.細胞内pHは運動開始40秒 (50%MVC) ～347秒 (10%MVC) まで安静時レベル (-6.95pHunit) 維持したものの, それ以降'低下を示した.また各測定項目 (pH低下率及びH₂PO₄-増加率) とも強度の上昇に伴いその変化の程度は増大を示した.
3) 筋内の酸素化レベルは, 全ての強度において運動開始時直後から直線的に低下を示した.しかしながらその後の変化は各強度間で異なり, 10%, 30%MVCではその後上昇し一定レベルを維持した.一方50%MVCではさらに低下し, 平均値において10%を下回っていた.
4) 各相対強度におけるpH低下率及びH₂PO₄-増加率と持続時間との間には, いずれも負の相関関係が認められた.pH低下率と持続時間との問にはr=-0.578～-0.871の相関係数が得られ, 10%, 30%MVCではそれぞれ有意 (P<0.05) であった.また, H₂PO₄-増加率との間にはr=-0.370～-0.740の相関係数が得られた.
本研究の結果から, 最大下の等尺性運動時における筋持久力 (持続時間) には, 筋興奮・収縮連関やエネルギー供給系に対して直接あるいは間接的に関与する細胞内pHの低下率が重要な因子であることが示唆された.

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本研究では, ラットを対象に持久性ランニングトレーニングを処方し, ラットの骨格筋Mb濃度の運動強度, 運動時間の影響および経時的変化の現象を明らかにすることを目的とし, さらにミトコンドリアの酸化系酵素活性の変化との比較を行った.得られた結果は以下の通りである.
1) 腓腹筋表層部を除く全ての筋 (ヒラメ筋, 腓腹筋深層部, 足底筋) において, 運動強度依存的にMb濃度が上昇した (運動強度の検討) .
2) CS活性は, ヒラメ筋, 腓腹筋深層部では低強度運動から, 足底筋や腓腹筋表層部ではより高い運動強度によって上昇した (運動強度の検討) .
3) 腓腹筋表層部を除く筋 (部位) においてMb濃度およびCS活性が運動時間の増加に伴って漸増し, 90分の運動時間によって十分な適応が得られた (運動時間の影響) .
4) Mb濃度はCS活性と比較して最大適応を得るためのトレーニング期間が長い傾向であった (期間の検討) .
以上のことから, ラットに持久性トレーニングを行わせた場合, (1) 運動強度の違いによるMbの変化は強度依存的に生じ, その様相はミトコンドリア酵素活性とは異なること, (2) Mb濃度の最大の増加率を得るためには, 一回に90分の運動時間が必要であること, (3) Mb濃度の増加には, ミトコンドリア酵素活性の増加と比較してより長い期間が必要であることが明らかになった.

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Previously, we observed that hypoxic pulmonary vasoconstriction (HPV) can be reduced by endurance exercise training. This study determined whether nitric oxide (NO) plays a role in inhibition of the HPV after endurance exercise training in isolated rat lung perfused with physiological saline solution containing meclofenamate. Sprague-Dawley rats were used, and were divided into two groups: a control (Cont) group and an endurance exercise-trained (ET) group. Endurance exercise training was carried every day on a small-animal motorized treadmill. The training protocol was 30 to 40 min/day and the rats ran at a speed of 15 to 30 m/min for 2 weeks. It appeared that HPV could be reduced by short-term endurance exercise training. The NO-forming enzyme inhibitor, N^G-nitro-L-arginine methyl ester (1.5×10^-8M, L-NAME), administered to the ET group increased the HPV compared in that of the Cont group. These findings indicate that endothelial NO synthesis may contribute to the inhibition of HPV in ET rats. Our data suggest that endurance exercise training promotes endothelium dependent-pulmonary vasodilation through the stimulation of NO released during HPV.

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本研究は青少年期における自覚疲労症状について, 自覚の経験及び重要度評価の観点から疲労症状の内容を踏まえて性差を検討した.学生730名 (男子290名, 女子440名) を対象に調査を実施した.54項目の自覚疲労症状質問項目の回答方法は疲労時に自覚する内容であるか否かの2件法と自覚疲労症状の内容としてどの程度重要であるかに関する7段階評定であった.項目毎に自覚の有無の比率と重要度評価の反応傾向及び平均値について性差を検討した.自覚疲労症状に対する重要度評価の平均値は, 男子において3.9～5.4, 女子において4.5～5.6であった.男女別に自覚の有無の比率を検討した結果, 全ての項目において自覚する確率の高いことが確認された.
自覚の有無及び性差を要因とする重要度の2要因分散分析の結果, 全ての項目において自覚の要因に有意差が認められ, 「自覚する」者の重要度の認識が高かった.一方, 性差の要因に有意差が認められた28項目はいずれも女子に高い値を示し, だるさ, 気力の減退及び焦燥・身体違和感の領域に顕著であった.
同一項目において自覚する者と自覚しない者とでは, 自覚する者の方がより自覚疲労症状を重要視すると推測された.また, 性の要因において有意差の認められた項目内容の多くは, 気力の減退, 焦燥・身体違和感に関する自覚疲労症状であり, 女子の方が男子よりもこれらの症状を重要視すると考えられた.
以上のことから, 自覚疲労症状の性差は, 自覚の経験及び項目内容の捉え方に因るものと推測され, だるさ, 気力の減退及び焦燥・身体違和感においてより強く反映されると考えられた.

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A study was conducted to investigate the relationship between the characteristics of torque production with special reference to eccentric and concentric muscle contraction and the structural and functional properties at the lower limb joints in the human kinetic chain. Ten male college athletes were tested with a isokinetic dynamometer (biodex) for eccentric and concentric torques during extension and flexion at the hip and knee, and plantar flexion and dorsiflexion at the ankle (angular velocity ; 30, 60, 120 deg/s) . The peak eccentric and concentric torques were higher in the order hip, knee and ankle joints, as the size of each muscle acting on its joint increased. However, the rate of peak concentric to eccentric torque (CON/ECC, %) was higher at the ankle joint than at the hip and knee joints. They tended to increase in the order of angular velocity ; 30, 60, 120 deg/s. These results suggest that the ankle joint is charactered by higher eccentric torque production. This characteristic is probably due to the fact that (1) the ankle joint is located at the end of the human kinetic chain and plays a role in transmitting the power to the ground effectively, (2) the muscle tendon complex acting at the ankle joint must have increased stiffness and tolerate great stretch loads to store and reuse the amount of elastic energy, (3) the hip and knee joints located at the center are the main sources of power supply. On the other hand, no significant correlations were observed among the torques at the hip, knee and ankle. These results suggest that torque production is independent at each of the lower limb joints, and is based on the structural and functional properties of each joint. These findings seem to be useful to clarifying the methods of strength and power training that can be adapted to the characteristics of torque production and the structural and functional properties of the hip, knee and ankle joints.

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A study was performed to examine sex and age differences in physique and physical fitness and the sex differences in the change of these parameters with age, and to clarify the relationship between the amount of exercise and fundamental physical fitness in 326 healthy elderly individuals over 60 years of age.
A total of 22 variables consisting of 9 items concerning body linearity, quantitative growth, circumference growth and posture, and 13 items representing 4 domains (muscular, joint, neural, and cardiorespiratory functions) were selected. The exercise performance index (EPI) was calculated as the product of frequency and duration (yr) of exercise. The sex and age differences in physique and physical fitness were examined using two-way ANOVA (sex × age group) . Post hoc tests using Ryan's procedure were carried out when the main effect of these factors proved significant. To examine the characteristics of changes in physique and physical fitness with age, Pearson's correlation coefficient was calculated, and linear regression analysis [test item was the dependent variable (X) and age was the independent variable (Y) ] was applied. Then significant differences in the regression coefficient and intercept between males and females were examined. Furthermore, curved-line regression analysis was executed for the above variables. Applying principal component analysis for 13 physical fitness items, the first principal component was interpreted as fundamental physical fitness for performance, and the above analysis was applied to the fundamental physical fitness score (FPS) . To examine the relationship between EPI and FPS, the difference in FPS among the three EPI groups was examined using analysis of co-variance (ANCOVA) with age as the co-variable.
The main findings of this study can be summarized as follows.
1. With regard to physique, males showed greater body linearity, and females had more skinfold. Sex differences in circumference growth were not as significant as those in body linearity and quantitative growth. Changes in physique with age were greater in females than in males, the change becoming obvious in individuals over 80 years of age.
2. With regard to physical fitness, males had superior muscular function and vital capacity, while females outperformed males in standing-reach. However, there was little sex difference in neural function. The trend for deterioration in physical fitness with age differed between the sexes among 4 domains of physical fitness. For example, in males muscular, neural, and joint functions deterioration significantly with age, while in females, all physical fitness variable did so. In addition, the age-related trends of deterioration in muscular function (grip strength and vertical jump), cardiorespiratory function (duration of breath-holding and vital capacity), and neural function (stepping) were differed between the sexes.
3. The FPS was higher in males than in females. However, FPS decreased significantly with age in both sexes.
4. It was inferred that among active and healthy elderly males and females who exercised regularly, FPS was not influenced by EPI.

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