Useful exercise protocol and method of evaluation for determining gas exchange threshold (VOA) / 体力科学

ABSTRACT

The purpose of the present study was to investigate a useful exercise protocol and method of evaluation for determining the gas exchange threshold (VO<SUB>2</SUB>GET) and correlation coefficient between VO<SUB>2</SUB>GET and maximal oxygen uptake (VO<SUB>2</SUB>max), which is an index of aerobic capacity. Five healthy male volunteers (age 25.6 ± 2.0 yrs; height 172.9±4.0 cm; weight 69.5±6.6 kg) performed exercise tests 82 times. Each volunteer randomly conducted a RAMP exercise (1 W⋅3 sec<SUP>-1</SUP>), STEP-1 exercise (20W⋅min<SUP>-1</SUP>) and STEP-2 exercise (40W⋅2 min<SUP>-1</SUP>), respectively, at least 4 to 8 rotations. The gas exchange parameters (VE, VO<SUB>2</SUB>and VCO<SUB>2</SUB>) for incremental exhaustive cycle ergometer exercise were measured using a“breath-by-breath”method. Three different methods of evaluation- (VE/VO<SUB>2</SUB>and VE/VCO<SUB>2</SUB>) exchange (M-1), V-slope method (M-2), and M-1 & M-2 (M-3) -were attempted to determine VO<SUB>2</SUB>GET. The VO<SUB>2</SUB>GET values, determined by three different methods (M-1, -2 and -3) of evaluation, were classified as‘easy’ (J-A) and‘difficult’ (J-B) in all tests. Reproducibility of VO<SUB>2</SUB>max and VO<SUB>2</SUB>GET were assessed using the coefficient of variation (CV) and correlation coefficients (r) between VO<SUB>2</SUB>max and VO<SUB>2</SUB>GET.<BR>The results are summarized as follows<BR>1) The means of the reproducibility of VO<SUB>2</SUB>max were determined among the 5 subjects by us ing RAMP, 4.8% (n=25), STEP-1, 3.1% (n=28) and STEP-2, 2.9% (n=29) exercise tests; STEP-2 exercise test values (CV) were lower than the others. There was no significant difference in the means of VO<SUB>2</SUB>max among the 5 subjects according to the RAMP and two STEP exercise tests (Two-way ANOVA) .<BR>2) The best reproducibility value of VO<SUB>2</SUB>GET among the 5 subjects was determined using RAMP exercise tests with the V-slope method (M-2) and evaluations were classified as easy (J-A) . The value (CV) was 2.8%. There was no significant difference in the VO<SUB>2</SUB>GET values (M-1 (J-A, -B), M-2 (J-A, -B) and M-3) (Two-way ANOVA) and their means among the 5 subjects concerning RAMP and two STEP exercise tests (Two-way ANOVA) .<BR>3) The best correlation coefficient (r) value between VO<SUB>2</SUB>max and VO<SUB>2</SUB>GET was obtained using RAMP exercise tests with M-2 (J-A) (r=0.976, n=20) .<BR>The present results indicate that the most useful exercise protocol and method of evaluation for determining VO<SUB>2</SUB>GET is the RAMP exercise test with the V-slope method.