Effects Of Training Load On Heart Rate Variability Of Elite Swimmers At Different Stages

Purpose:The first is to study the training load and heart rate variability(HRV)in plateau,plain and before the race.The second is to study the effect of the changing characteristics of training load on heart rate variability(HRV),aiming to discuss whether heart rate variability(HRV)can be used as the monitoring of training load.Methods:(1)research objects: 6 national elite swimmers(male-3,female-3),men's height:188±5.89(cm),women's height:175±4.64(cm),were all international athletes.(2)research scheme:Six athletes who are preparing for the national swimming championship are selected to train at the plateau training stage in the preparatory period,the plain training stage and the pre-competition training stage respectively.The plateau training phase was 4 weeks' training(G1-G4)at the hairidges training base in yunnan province,1890 meters above sea level;the plain training phase was 4 weeks' training(P1-P4)and the pre-competition training phase was 3 weeks' training(S1-S3)at the training bureau of the general administration of sport in Beijing.Elite swimmers were tested once a week in each session(a total of 11 times)and three times in the week before each session(a total of three times)for their HRV and routine blood levels in the morning.Blood was collected immediately after each HRV test.Record individual exercise duration and individual RPE value after each training session(land and water).In addition,in the three stages,the special performance of the test.(1)test indicators Heart rate variability(HRV)test index:Time domain index:SDNN,RMSSD,SDSD;Frequency index:TP,HF,HFn.u.,LF,LFn.u.,LF/HF.Indicators of body function state:WBC,RBC,Hb,CK,BU,T,C,T/C Results:(1)variation characteristics of training load in different stagesIn the plateau training phase,the training load showed a gradual increase,with an increase of 3.8%,which was not significant(P>0.05).In the later phase,the training load showed a downward trend,but the G4 value was still greater than the G1 value.In the plain training stage,the training load showed a decreasing trend,with a decrease of 13.8%,and the decreasing range was not significant(P>0.05).However,the training load value at the early stage of this stage showed a peak.In the pre-competition training stage,the training load showed a negative slope and a linear decrease,with a decrease of 40.33%,which was significant(P<0.05).(2)change characteristics of HRV indexes in different stagesThe activity of parasympathetic nerve dominated the early stage of altitude training.TP increased by 167% and G1 peaked,indicating a greater increase in parasympathetic activity than sympathetic activity.Sympathetic nerve was dominant in the later stage,indicating that the decreasing trend of parasympathetic nerve index was significantly greater than the amplitude of sympathetic nerve activity.In the plain training stage,the training load showed a downward trend,and the sympathetic nerve activity was dominant in the whole stage,and TP,RMSSD,SDSD,SDNN,HF and LF were at the lowest values in this stage.At the beginning of pre-race training,SDNN and TP increased by 4.8% and33.9% respectively,with the decrease of sympathetic nerve activity and the increase of parasympathetic nerve activity.In the later stage,the activity of sympathetic nerve was mainly enhanced,and the TP and SDNN indexes were the lowest,while the parasympathetic nerve indexes were significantly decreased.(3)correlation between training impulse at different stages and HRV indexIn the plateau training stage,there was a significant negative correlation between training impulse and HF of HRV index(P < 0.05).In the plain training stage,there was a significant positive correlation between the training impulse and SDNN,SDSD and RMSSD of HRV indexes(P<0.05).In the pre-competition training stage,there was a significant positive correlation between the training impulse and SDNN,TP,HFand HFn.u of HRV indexes(P<0.05).There was a significant negative correlation between training impulse and LF/HF and LF of HRV index(P<0.05).Conclusion:1.The difference of training load in different stages.SDNN and TP indexes generally show the same trend from growth to decline in the three different stages.During the plateau training,the training load first increased and then decreased,and parasympathetic innervation dominated the transition to sympathetic innervation.The peak of the training load in the plain training stage makes SDNN,TP and parasympathetic index(SDSD),RMSSD,HF and LF and LFn.u of the parasympathetic index appear peaks,and the parasympathetic activity and sympathetic activity change from increasing to decreasing,with the sympathetic activity as the leading factor.In thetraining stage before the competition,the training load showed a downward trend,and the parasympathetic activity mainly changed to the sympathetic activity,and the sympathetic nerve was the dominant one.2.The indexes related to heart rate variability(HRV)have synchronicity and correlation with the training loads at different stages,suggesting that heart rate variability(HRV)can be used as an auxiliary means to monitor the training loads of athletes in swimming events.