体力科学
Online ISSN : 1881-4751
Print ISSN : 0039-906X
ISSN-L : 0039-906X
52 巻 , 1 号
選択された号の論文の10件中1~10を表示しています
  • 2003 年 52 巻 1 号 p. 1-27
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
  • 山田 洋, 木塚 朝博, 増田 正, 横井 孝志, 金子 文成, 金子 公宏, 岡田 守彦
    2003 年 52 巻 1 号 p. 29-42
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    We studied the mechanism for slowing surface electromyography (EMG) during fatiguing contraction using superimposed M-wave analysis. Seven healthy male subjects exerted 60% maximum voluntary contraction of isometric abductions in the left first dorsal interosseous muscle (FDI) until exhaustion. Simultaneously with voluntary contractions, the ulnar nerve was electrically stimulated at supramaximal intensity, and volitional EMG and superimposed M-waves were obtained. We examined the behavior of muscle fiber conduction velocity (MFCV) and median frequency (MDF) for both EMG, with the following results:
    1) MFCV calculated from volitional EMG of FDI was about 6 m/s during 60% MVC.
    2) The waveform of voluntary EMG detected from FDI slowed in all subjects during fatiguing contraction at 60% MVC, indicating fatigue had developed in the muscle.
    3) As fatigue progressed, the waveform of the superimposed M-wave tended to decrease in amplitude and increase in duration.
    4) As fatigue progressed, MDF and MFCV in volitional EMG decreased significantly (p<0.04) . The rate of change was larger in MDF than in MFCV (p<0.01) .
    5) As fatigue progressed, MDF and MFCV in the superimposed M-wave decreased significantly (p<0.01) . The rate of change was larger in NIDF than in MFCV (p<0.05) .
    These results suggested that MFCV and other peripheral factors affected the slowing of volitional EMG. Elongation of the depolarization zone in muscle fiber is proposed as a peripheral factor.
  • 八十島 崇, 木塚 朝博, 埜口 博司, 白木 仁, 向井 直樹, 下條 仁士, 宮永 豊
    2003 年 52 巻 1 号 p. 43-50
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    Electromyographic activity of the shoulder muscle at 20 and 90°abduction (20 Abd, 90 Abd) during external rotation was investigated in seven healthy men with no history of injury or instability of the shoulder joint.
    Electromyography (EMG) was recorded using intramuscular fine-wire electrodes inserted into the M. Supraspinatus, M. Infraspinatus and M. Teres minor, and with bipolar surface electrodes on the middle and posterior parts of M. Deltoid anti the upper and middle parts of M. Trapezius. To compare activity in different muscles, the integrated EMG (iEMG ) activity of each muscle was normalized.
    M. Infraspinatus and M. Teres minor showed significantly higher activity at both the 20 Abd and 90Abd compared with the middle and posterior parts of M. Deltoid and upper parts of M. Trapezius. M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius all showed a difference in activity level between the two positions.
    These findings suggest that when M. Infraspinatus and M. Teres minor contribute to external rotation as a stabilizer and prime mover, consecutively, M. Supraspinatus, the middle and posterior parts of M. Deltoid, and upper and middle parts of M. Trapezius function according to the positions. Moreover, the activity of the upper and middle parts of M. Trapezius in 90Abd should influence stabilization, adduction and upward rotation of the scapula. Therefore, we conclude that the external rotation position is closely related to shoulder muscle activity and coordination.
  • 山田 洋, 木塚 朝博, 増田 正, 関 和彦, 横井 孝志, 金子 文成, 岡田 守彦
    2003 年 52 巻 1 号 p. 51-64
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    The purpose of this study was to examine the effects of short-term immobilization on the maximum voluntary contraction (MVC) force. The first dorsal interosseus (FDI) of 10 healthy male adults was immobilized for 1 week using casting tape. Atrophy of the muscle was estimated from a cross sectional view of magnetic resonance images (MRI) . To clarify the factors of a peripheral neuromuscular system contributing to the change in the MVC force, twitch force at rest was measured. The contribution of central factors was estimated from a voluntary activation (VA) index, which was obtained by the twitch interpolation method.
    The MRI showed no significant changes in the cross sectional area. The MVC force declined after immobilization (p<0.01), and recovered after 1 week from the termination of immobilization (p<0.01) . Both the twitch force at rest and the VA at MVC declined after immobilization (p<0.01), and recovered after 1 week (p<0.05) .
    The results indicate that the temporary decline of the MVC force was not accompanied by atrophy of the muscle. Furthermore the decline of the MVC was caused both by the deterioration of peripheral and central functions in the neuromuscular system. Possible factors in the peripheral and central neuromuscular systems affected by the immobilization were discussed.
  • 本田 亜紀子, 長澤 省吾, 梅村 義久
    2003 年 52 巻 1 号 p. 65-73
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    本研究は, 低頻度のジャンプトレーニングが, ラットの骨量, 骨強度および骨形態に及ぼす影響を検討することを目的とした.異なる日程においてIntactおよびOVX実験を設定し, 各トレーニング群には, 10回/日, 週1日あるいは3日, 8週間のジャンプトレーニングを行わせた.ジャンプの台高はIntact実験では45cm, OVX実験では40cmに設定した.それにより以下のような結果が得られた.
    1.週1日のトレーニングでも, Intactラットと同様, OVXラットの骨量・骨強度の増加に対して十分な効果がある
    2.骨量・骨強度におけるセデンタリー群に対する各トレーニング群の変化率は, 両実験間で同様の上昇を示した
    3.骨量・骨強度の増加は, 両実験ともトレーニング頻度に大きくは依存しなかった
    4.骨形態の変化に関しては, Intact群では横軸方向への肥大が見られ, 特に皮質骨面積の増加が顕著であったが, OVX群では有意な変化は見られなかった
    以上のことより, ジャンプトレーニングは週1日と低頻度であってもIntactおよびOVXラットの骨量・骨強度増加に対して効果があり, セデンタリー群に対する各トレーニング群の変化率も両ラットで同じであった.骨形態に関して, OVXラットでは顕著な変化は見られなかったが, 骨量, 強度増加の点から皮質骨における質的変化および改善があったと考えられた.このことから, 週1日でもトレーニングすることが重要であることが示唆された.
  • 新矢 博美, 芳田 哲也, 高橋 英一, 常岡 秀行, 中井 誠一
    2003 年 52 巻 1 号 p. 75-88
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    The effects of fencing uniforms (U) on thermoregulatory responses were analyzed in both practical field investigation (PFI) and laboratory experiment (LE) . In PFI, six fencers (college-aged) performed regular fencing practice wearing U and wearing a short-sleeved shirt and pants (T) in summer. Rectal temperature (Tr), chest skin temperature (Tch), mask temperature (Tmk), heart rate (HR) and sweat rate (SR) were measured during fencing practice. In LE, seven male college-aged subjects performed three sessions of 20-min cycling at light intensity (250 W/m2) in a room temperature maintained at 28 WBGT (wet bulb globe temperature) . Esophageal temperature (Tes), mean skin temperature (Tsk), mean body temperature (Tb), HR, and SR were measured during exercise wearing U and in a semi-nude condition (N) . In both PFI and LE, increases in Tch, Tsk, Tb, Tes, Tr and SR were significantly (p<0.001) greater when wearing U than when wearing T and N. In PFI, the maximal value of Tr correlated significantly with the maximal values of Tch (r=0.513, p<0.001) and SR (r=0.635, p<0.001) during practice wearing U and T. In LE, positive correlations between Tsk and Tes (r=0.797, p<0.001), and between Tb and SR (r=0.658, p<0.02) were found at the end of exercise wearing U and N. In PFI, although the Tsk decreased within a few minutes of a decrease in Tmk, a significant relationship between the decrease in Tmk and Tsk or Tr was not observed during fencing practice. These results demonstrate that when wearing U, a higher skin temperature induces core temperature elevation, and higher skin and core temperatures are associated with increases in SR and HR during exercise in a hot environment. Thus, wearing light clothing during exercise, and taking off the fencing jacket and mask during rest periods would be recommended to reduce the heat stress during fencing practice in hot environments.
  • 真鍋 芳明, 横澤 俊治, 尾縣 貢
    2003 年 52 巻 1 号 p. 89-97
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    The squat is used for strength training of the hip and knee joint muscles. The weight to be lifted is important for multi-joint movement like a squat, because weight differences are thought to directly affect joint load. The purpose of this study is to compare the activity of eight muscles crossing the ankle, knee and hip joints during three kinds of squats with different loads (60%, 75% and 90% of 1RM) . Eight male athletes performed squats with three different loads. Variables such as net torque, power and work about the joint were calculated only during the ascending phase of each squat. At the same time, surface electrodes was placed over the eight lower extremity muscles, and %iEMG was also calculated during the ascending phase of each squat. Elector spinae and Biceps femoris muscle activity of 90% was significantly greater than at 60%. Gluteus maximus muscle activity at 90% was significantly of 75% and 60%. Mean torque and work on the hip joint increased significantly as load increased from 60% and 75% to 90%. For the knee, mean torque increased significantly from 60% to 90%. These results that a heavy weight like 90% of 1RM used in squat exercise increases the load on the hip joint extensor muscles.
  • 鈴川 一宏, 谷 浩充, 小山内 弘和, 白土 男女幸, 中野 昭一
    2003 年 52 巻 1 号 p. 99-110
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    本実験では, 実験1としてホエイペプチドと大豆ペプチドのラット翻転腸管による腸管壁通過現象の比較検討を行った.また, 実験2として強制運動を行わせたラットを用い, コラーゲンペプチドの腸管壁通過現象について検討を行った.
    すなわち, 実験1では, ラットの翻転腸管の粘膜側にホエイペプチドおよび大豆ペプチドを添加した場合, 紫外部吸光度増加面積およびアミノ酸分析の成績から, 両者ともに腸管壁を通過したことが認められた.なお, この両ペプチドの腸管壁通過を比較した場合, ホエイペプチドが大豆ペプチドより有意に高値を示し, ホエイペプチドの方が大豆ペプチドよりも腸管壁を通過しやすいことを示していた.
    次に, 実験2の強制運動を行ったラットでは, 体重の増加に抑制がみられ, 臓器重量からも運動による生体への影響が認められた.また, Training群とControl群における翻転腸管の粘膜側にコラーゲンペプチドを添加した場合には, 両群ともにコラーゲンペプチドが腸管壁を通過していた.しかし, この両群のコラーゲンペプチドの腸管壁通過現象には有意の差は認められなかった.したがって, コラーゲンペプチドが腸管壁を通過することは明確であったが, 強制運動による腸管壁通過現象には著明な影響はみられなかった.
  • 樋口 博之, 綾部 誠也, 進藤 宗洋, 吉武 裕, 田中 宏暁
    2003 年 52 巻 1 号 p. 111-118
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    Daily energy expenditure has been measured by the physical activity recording and/or the questionnaire method. Recently, the accelerometer or pedometer is used to measure daily energy expenditure. The purpose of this study was to examine validity of the pedometer with accelerometer and to compare the daily physical activity between young and older Japanese. To examine validity of the pedometer, 10 young subjects worn the pedometer (Lifecorder) on the waist and then performed the walking test. Energy expenditure was measured by the expired gas analysis during the test. Fourtythree young and 54 older subjects worn the Lifecorder on the waist during free-living condition for 14 days. The intensity of Lifecorder had a high correlation with the physical activity intensity (METs) (r=0.958, P<0.001) . In the free-living condition, daily energy expenditure was 2171±305 kcal in young and 1617±196kcal in older (P<0.001) . Total step in young was significantly higher than older (young: 9490±2359 steps ; older: 6071±2804 steps, P<0.001) . There was no significant difference in the duration of physical activities at the Lifecorder intensity 1 such as desk working, watching TV sitting on a sofa and driving a car. However, the duration more than the intensity 2 corresponding to 2.2 METs in young subjects was longer than that in older (P<0.001) . We concluded that in older subjects, not only amounts of daily energy expenditure but also intensities of daily living were lower compared to the young subjects.
  • 山内 秀樹, 益子 詔次, 木村 真規, 宮野 佐年, 米本 恭三
    2003 年 52 巻 1 号 p. 119-130
    発行日: 2003/02/01
    公開日: 2010/09/30
    ジャーナル フリー
    若齢ラットを用い, 非荷重ならびに再荷重に伴う脛骨の変化と等尺性抵抗運動の効果について検討し, 以下の成績を得た.
    3週間の非荷重により脛骨全体の脱脂乾燥重量, 骨塩量, 骨密度はそれぞれ8%, 10%, 6%低下した.脱脂乾燥重量と骨塩量は3週間の再荷重により対照レベルに回復したが, 骨密度の回復はみられなかった.
    長軸に沿って7等分された領域別 (近位からR1~R7) に骨密度を測定した結果, 非荷重による骨密度の低下はR1~R4とR7で観察された.骨密度の低下率は部位により異なり, とくにR1で顕著であった.また, R2~R4の骨密度は再荷重後も対照群に比べ低値のままであった.
    骨幹部の静的3点曲げ試験による最大破断荷重, エネルギー量, 変形量に非荷重や再荷重による影響はみられなかった.
    非荷重はヒラメ筋 (-38%) , 足底筋 (-14%) , 腓腹筋 (-25%) , 前脛骨筋 (-8%) , 長指伸筋 (-8%) , 大腿直筋 (-17%) の重量低下を引き起こしたが, ヒラメ筋を除くすべての筋の重量は再荷重により回復した.
    等尺性抵抗運動は非荷重によるヒラメ筋と腓腹筋の重量低下を軽減したが, 再荷重による筋重量の回復を助長しなかった.また, 骨密度の非荷重による低下や再荷重による回復に対する影響も観察されなかった.
    以上の結果から, 1) 骨密度の領域別解析は局所における骨代謝の評価として有用である'2) 荷重条件の変化に対する骨応答は必ずしも骨格筋の応答に依存しているわけではない, 3) 骨量低下からの回復は筋萎縮からの回復に比べて遷延し, 骨密度の回復には非荷重期間以上の長期を要すると結論された.非荷重や再荷重と関係した骨量と筋量の維持・増進を図る効果的な運動処法の確立には更なる研究が必要と考えられた.
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