下り勾配トレッドミル歩行の運動負荷について  [in Japanese] The Work Load during Downhill Walking on Treadmill  [in Japanese]

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Author(s)

    • 佐々木 誠 SASAKI Makoto
    • 仙台医療技術専門学校:東北大学大学院医学系研究科障害科学専攻内部障害学分野 Sendai College of Medical Technology:The Section of Internal Medicine and Disability Prevention, Disability Science, Division of Medicine, Tohoku University Graduate School

Abstract

本研究の目的は,下り勾配トレッドミル歩行の呼吸循環器障害患者への臨床応用の可能性の有無を考察することである。若年健常女性27名を対象に,下り勾配トレッドミル歩行の運動負荷について,上り勾配トレッドミル歩行のそれとの対比を含めて酸素搬送系の各指標および自覚的運動強度(RPE)から検討するために,上り勾配と下り勾配でのトレッドミル運動負荷試験を実施した。運動負荷試験プロトコールは勾配0%から ± 15%まで7段階に2分毎にそれぞれ正負に漸増するものである。上り勾配では全指標が勾配漸増に伴って増加したのに対して,下り勾配では酸素摂取量(VO<sub>2</sub>/kg)は-7%まで漸減した後-10%を境に増加傾向を示したが,全値とも平地歩行より低値であった。酸素脈(O<sub>2</sub> pulse)もVO<sub>2</sub>/kgと同様の推移であったが,心拍数(HR)は平地よりも僅かに低値のまま不変であり,二重積(RPP)は平地歩行と同値で推移した。また,分時換気量(V<sub>E</sub>)は-10%を最小とするVO<sub>2</sub>/kgと近似した推移を示したが,これは一回換気量(V<sub>T</sub>)の漸減が理由と考えられ,呼吸数(RR)は上り勾配と同様に漸増し続けた。更に,RPEは上り勾配ほど急峻ではないものの漸増した。以上より,下り勾配歩行は酸素需要量が少ないにもかかわらず,心筋酸素需要は減少せず浅く速い呼吸がもたらされ,設定運動強度以上に“きつい運動”と感じられる特性があり,呼吸循環器障害患者への臨床応用に否定的な要素が多かった。しかしながら,トレナビリティー,慣れの効果,筋収縮や歩行形態の相違による末梢効果や応用歩行への適応効果が期待される可能性が残されており,更なる検討が必要と考えられた。

Study was made to determine whether downhill walking on treadmill would be applicable to cardiopulmonary disorder patients. To investigate work load during downhill walking on the treadmill including uphill walking based on oxygen transport and rating of perceived exertion (RPE), 27 young healthy female volunteers participated in uphill and downhill walking. The treadmill gradient was increased gradually from stage one (0% gradient) to stage seven (± 15% gradient) in positive or negative direction. <br>All indices gradually increased with positive gradient in uphill walking. Oxygen intake (VO<sub>2</sub>/kg) in downhill walking decreased -7% down to the bottom borderline at the -10% gradient, and then increased. Oxygen intake (VO<sub>2</sub>/kg) was less than in level walking. Oxygen pulse (O<sub>2</sub> pulse) showed similar change, but heart rate (HR) remained constant at slightly less than in level walking, and rate-pressure product (RPP) remained stable at that of level walking. Minute ventilation (V<sub>E</sub>) showed transition similar to VO<sub>2</sub>/kg, the lowest value being -10%. The gradual decrease in tidal volume (V<sub>T</sub>) may have been the reason for this since respiratory rate (RR) continued to increase as well as in uphill walking. Though RPE in downhill walking did not rise as much as in uphill walking, it increased gradually. <br>Myocardial oxygen demand would thus appear not to decrease, rapid shallow breathing may occur and there may be the sensation of "heavy" exercise, in spite of low oxygen demand. This exercise mode may thus not be sufficiently applicable to cardiopulmonary disorder patients. But there appears the possibility of good results through training, learning through exercise and different muscular contractions, etc. Additional investigation should thus be continued.

Journal

  • Physical Therapy Japan

    Physical Therapy Japan 27(1), 17-23, 2000

    Japanese Society of Physical Therapy

References:  29

Cited by:  2

Codes

  • NII Article ID (NAID)
    110004010450
  • NII NACSIS-CAT ID (NCID)
    AN10146032
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0289-3770
  • Data Source
    CJP  CJPref  NII-ELS  J-STAGE 
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