The Research Of Response And Adaptation Of Altitude Training Of Juvenile Swinlmers

Background and Objectives:Swimmers who train using hypoxia may be among the best trained athletes, and that even a slight improvement in physical endurance might result in the shortening of swimming time in a given competition, and the achievement of a personal best, which is hard to obtain by normal training methods, when the personal results of the swimmer have reached a plateau. For children, the function of physical and organs grow rapidly, whether athletes lower than this age could participate in AT has remained unclear.33young swimmers from Shanxi Province paticipated in our research. They were divided into two groups, the high age group with an average age of13.53±0.87years and the low age group with an average age of11.25±0.86years. The altitude training was arranged in sports training base of Qinghai province(2366m) for five weeks including3phases(adapitive training for1week; altitude trainig for2weeks; de-adapitive training in plain for2weeks).Methods:1. Observed the variation of serum hypoxia inducible factor HIF-la and EPO of athletes during altitude training to research the difference of response and adaptation to hypoxia between children and adolescents.2. Observed the variation of red blood cell count, HGB and other parameters of athletes during altitude training to investigate the variation of oxygen carrying capacity of children athletes during altitude training.3. Color Doppler ultrasound system was used to measure the morphology and function of the athelets’heart, and to investigate the variation of cardio function of children athletes during altitude trainning. The PASP was calculated from the pressures wave Doppler echocardiography across tricuspid valve. The serum ET-1and NO were measured to investigate the reason of PASP change.4. Through5X200m incremental exercise test, calculate the individual lactate threshold of athletes, to research whether altitude training could improve the exercise performance and the performance in competition of children athletes.Results:1. There was a significant difference of serum HIF-1α and serum EPO in athletes at various time points during altitude trainning (P<0.05); There was no significant difference between groups (P>0.05); When entering the altitude, the serum HIF-1a of all athletes were significantly higher than that in plain. When entering the plateau the serum EPO of all athletes was significantly higher than that in plain, and recoverd to to before plateau level after14days on altitude.2. There was a significant differences of RBC, HGB and HCT in athletes at various time points during altitude trainning (P<0.05); There was no significant difference between groups (P>0.05); When entering the altitude, RBC and HGB of all athletes were significantly higher than that in plain. The HCT of all athletes were significantly lower than that before altitude after one week on altitude, and were significantly higher than that before altitude after two weeks on the plateau and after return to plain.3. Immediately after exposure to altitude, the resting heart rate increased, stroke volume decreased and cardiac output increases significantly. There was no significant differences of left ventricular tei index and right ventricular tei index in athletes at various time points during altitude trainning (P>0.05); But there was a significant difference of left ventricular tei index and right ventricular tei index in athletes at various time points after altitude training. The left ventricular tei index and right ventricular tei index were significantly lower than that before altitude training.4. There was no significant change of OBLA-V and OBLA-bla before and after altitude trainining.Conclusions:1. The serum HIF-1α and serum EPO of lower age group have a similar variation trend with the higher age group during altitude training.2. The RBC, HGB and HCT of the lower age group have a similar variation trend with higher age group athletes during altitude training.3. The hypoxia exposure and exercise training in altitude have no significane effect on cardio function of young athletes;4. The hypoxia exposure could cause the PASP of athletes elevated; The elevated PASP have no significantly effect on the cardio function of the athletes.5. The altitude training have no significant effect on the atheles’exercise performance.