Relationship between CO2 excess due to lactic acid production during exercise and endurance performance / 体力科学

ABSTRACT

A study was conducted to assess the relationship between CO<SUB>2</SUB> excess due to lactic acid production during exercise and endurance performance in order to clarify the availability of CO<SUB>2</SUB> excess as an index of endurance capacity. Four healthy males (control group; CON) aged 21-24 years, and six male long-distance runners (LDR) aged 18-22 years, were subjected to incremental maximal testing on a cycle ergometer and 12-min exhaustive track running. The results obtained are summarized as follows.<BR>1) Mean values (±SD) of CO<SUB>2</SUB> excess (m<I>l</I>) were 3, 442±677 m<I>l</I> for LDR and 2, 667±437 m<I>l</I> for CON, respectively. On the other hand, the mean value of CO<SUB>2</SUB> excess per unit body weight (CO<SUB>2</SUB> excess/w) obtained in LDR (59.1±9.07 m<I>l</I>⋅kg<SUP>-1</SUP>) was significantly higher than that in CON (40.3±3.54 m<I>l</I>⋅kg<SUP>-1</SUP>) (p<0.01) .<BR>2) The ratio of CO<SUP>2</SUP> excess/w to &Delta;LA (the difference between blood lactate at 1 min after exercise and that at rest) showed a tendency to be higher in LDR (5.59±1.16 m<I>l</I>⋅kg<SUP>-1</SUP>⋅mmol<SUP>-1</SUP>) than in CON (4.46±0.69 m<I>l</I>⋅kg<SUP>-1</SUP>⋅mmol<SUP>-1</SUP>) . However, there was no significant difference between these two groups in the ratio of CO<SUP>2</SUP> excess/w to &Delta;LA.<BR>3) The CO<SUP>2</SUP> excess/w (m<I>l</I>⋅kg<SUP>-1</SUP>) was significantly related to Vo<SUB>2</SUB>max (r=0.813, p<0.01) and Vo<SUB>2</SUB>AT (r=0.892, p<0.001), respectively. Moreover, CO<SUB>2</SUB> excess/w was significantly correlated with &Delta;HCO<SUB>3</SUB>- (the difference between blood bicarbonate at l min after exercise and that at rest) (r=0.649, p<0.05) .<BR>4) The CO<SUB>2</SUB> excess (m<I>l</I>) and CO<SUB>2</SUB> excess/w (m<I>l</I>⋅kg<SUP>-1</SUP>) were significantly correlated with 12-min exhaustive running performance (r=0.715, p<0.05, r=0.933, p<0.001), as was the ratio of CO<SUB>2</SUB> excess/w to d LA (r=0.671, p<0.05) .<BR>5) From these results, it was suggested that the CO<SUB>2</SUB> excess/w and the ratio of CO<SUB>2</SUB> excess/w to &Delta;LA could be important factors related to performance of endurance exercise (i. e., 3, 000-5, 000 m running) accompanied by blood lactate accumulation.