著者

福岡 義之 近藤 徳彦 後藤 真二 池上 晴夫

出版者

日本体力医学会

雑誌

体力科學 (ISSN:0039906X)

巻号頁・発行日

vol.40, no.1, pp.60-73, 1991-02-01

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Amplitude and phase response of ventilation (V_E), carbon dioxide output (VCO_2) and oxygen uptake (VO_2) during sinusoidally varying work load for periods (T) of 1〜16 min were studied in six healthy men. The relationships between these parameters and aerobic capacity (VO_2max, ATVO_2) were also examined.The results and conclusions obtained were as follows : (1)The relationship between the period (T) of exercise and amplitude response of VO_2,VCO_2 and V_E was well described by first-order exponential models.However,the relationship between the period of exercise and the phase shift (phase responses of VO_2,VCO_2,and V_E) was better described by complex models comprising a first-order exponential function and a linear equation.This can be explained by Karpman's threshold theory.(2)High negative correlations were observed between the steady-state amplitude (A) of phase response or the time constants (〓) of amplitude response and VO_2max,and ATVO_2.Significantly high negative correlations for all gas exchange parameters may be more rapid in individuals with greater aerobic capacity.(3)A close relationship between the response of VCO_2 and V_E was demonstrated by a higher correlation coefficient than that between VO_2 and VCO_2 or between VO_2 and V_E.This call be partly,but not completely,explained by the cardiodynamic theory.

著者

西保 岳 後藤 真二 鍋倉 賢治 池上 晴夫

出版者

日本体力医学会

雑誌

体力科学 (ISSN:0039906X)

巻号頁・発行日

vol.36, no.4, pp.195-201, 1987

被引用文献数

2

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The purpose of this study was to investigate the effects of contraction force and the pooled blood volume in the calf on the pumping action of calf muscle contraction. Calf blood volume was controlled by lower body negative pressure (LBNP) and isometric contraction of calf extensor muscle was performed using a handmade dynamometer in recumbent position. The relative volume changes (&Delta;V/V%) of calf were determined using rubber straingage, when isometric contractions (5, 10, 20, 40 and 60 kg) of the calf muscle were repeated under LBNP of 0, -20, -40, and -60 mmHg.<BR>During resting condition, &Delta; V/V was increased by 1.04% under -20 mmHg LBNP, 1.88% under -40 mmHg, and 2.54% under -60 mmHg. These increases of &Delta;V/V were due to the increased blood pooling in the calf. It was shown that the increased blood volume was almost expelled by several bouts of muscle contractions of proper force. The optimum force of contractions for expelling pooled blood was 20 kg under -20mmHg LBNP, and 40 kg under -40 and -60 mmHg LBNP. And it was apparent that the effectiveness of muscle pump was accumulated with repeating contractions, arriving to a plateau after several bouts.<BR>It was shown that the effect of muscle pump in the given contraction force was more effective under the condition with more amount of blood contained in the calf, but the muscle pumping action by light contraction forces couldn't overcome the effect of severe LBNP.