| Purpose:The purpose of this study is to measure the energy supply characteristics of athletes by MAOD method,including energy supply ratio,VO2max,running economy,maximum accumulated oxygen deficit,accumulated oxygen deficit during exercise,blood lactate and oxygen uptake,and measure the speed index(speed variability)related to energy distribution,analyze the correlation between the above energy supply characteristics and speed index and sports performance,to explore sensitive indicators that reflect sports performance.Method:The research object is 400m(11 male)athletes,including 4 first-class athletes and 7 second-class athletes(age 19.7± 1.1 y.o,height 177.4±5.1 cm,weight 68.6±6.3 kg).In the first part the subjects(on the selected date)were given laboratory test exercise:(1)Incremental load test:the subjects wore portable gas metabolism analyzer,started at 10km/hr on the treadmill,increased lkm/hr every 2min,and stopped after exhausted.The gradient of treadmill is set at 1%.This test can obtain the maximum oxygen uptake to evaluate aerobic capacity.(2)Constant load test:according to the maximal oxygen uptake intensity of incremental load test,subjects completed five levels of constant load test(50%,60%,70%,80%and 90%VO2max),each level lasted for 10 minutes,the average oxygen uptake in the last 2 minutes of each level can be used to evaluate the economics of running.(3)Supramaximal test:the subjects were required to exercise on the treadmill with a gradient of 1%to exhaustion(≥ 2min)at 110%maximal oxygen uptake,the maximum cumulative oxygen deficit of the test can be used to evaluate the anaerobic capacity.The second part is the special 400m test of the outfield track and field.Before the test,the portable gas metabolism analyzer was worn,and fingertip blood lactate samples were collected 30 seconds before running and 1,4,7,10 minutes after exercise.Segment every 50 meters.It is divided into 8 segments to calculate the change percentage of segment speed and average competition speed.Results:(1)The energy supply characteristics of the laboratory test:the maximum oxygen uptake is 57.73±2.14 ml/kg/min,the running economy RE90(90%VO2max)is 54.34±2.15,MAOD is 58.99±12.23 ml/kg/min.(2)The energy supply characteristics of the 400-meter running test:the aerobic and anaerobic energy supply ratios are 47.05±4.32%and 52.95±4.32%,respectively;The total coefficient of variation of VO2 in the 400-meter segment is 2.17±0.47,the total coefficient of variation of the percentage of aerobic energy supply is 2.99±0.74,and the total coefficient of variation of the percentage of anaerobic energy supply is 2.12±0.52,the accumulated blood lactate is 15.5±2.04 mmol/1.(3)The result of the 400-meter race was 54.2±1.44 s,and the total speed variation coefficient of the segment speed was 1.27±0.23.The peak speed of the 400-meter segment appeared in the 50-150-meter segment,and the oxygen uptake peak of the 400-meter segment appeared in the within 200-250 meters.Pearson correlation analysis results show that:total coefficient of variation of speed(r=-0.57)are respectively negatively correlated with athletic performance(P<0.5),there is no correlation between other energy metabolism indexes and sports performance(P>0.5).Conclusion:1.The 400-meter athletes selected in this study(sports performance of 54.2±1.44 s),the energy supply ratio measured by the maximum cumulative oxygen deficit method is 47.05±4.32%for aerobics and 52.95±4.32%for anaerobics;2.The higher the MAOD,the better the performance,the contribution of anaerobic ability to athletes’ performance is greater,that is pace may have an impact on athletic performance;3.This study has not found that VO2max,RE,AOD during exercise,accumulated blood lactate and VO2 it is a sensitive indicator of sports performance. |
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