Study On The Relationship Between HRV And Physical Function Of Elite Swimming Athletes In Different Stages Before Competitions

Research purpose:The purpose of this study was to explore the characteristics of the HRV of elite swimmers in the training stage of winter training and pre-competition training and its correlation with the physical function status index,and to provide a reference for the application and further research of HRV in the field of training monitoring.Research method:(1)The research object:Shanghai Swimming team 5 elite male athletes.(2)The Research scheme:Select the stage of plateau training in winter training and the stage before the finals of the National Games in preparation for the 13 th National Games.In the plateau training stage,a seven-week plateau training was conducted in Duoba,Qinghai province,2388 meters above sea level,and Kunming,Yunnan,1890 meters above sea level(sea level-1 week in Qinghai Province-6 weeks in Kunming-sea level).The previous week of the plateau was expressed as G1.G2-G8 at 7 weeks and G9 one week after the plateau.A total of 7 weeks of follow-up tests were carried out in the final stage,which were expressed as S1-S7 respectively.A total of Six HRV tests were performed at G1-G3,G5,G7,G9 during the recovery period.seven HRV tests were performed at S1-S7 during the recovery period.Blood was collected on a quiet,empty stomach every Monday morning.The venous blood was collected at S1,S2,S3,S5,S7 weeks,and take blood at the fingertips at G3,G7,S4,S6 weeks.(3)Test indicators:(1)Physical function state index:HB,WBC,CK,BU,T,C,T/C.(2)Heart rate variability:SDNN,RMSSD,SDSD,TP,HF,LF,LF/HF,VLF.(3)Endocrine index of cardiac autonomic nervous system:Cardiovascular endocrine indexes:NO,ET-1.Indicators of autonomic neurotransmitters: E,NE,DA;ACHResearch results:(1)Changes of athletes' physical function in different training stages The HB was at a high level during the high altitude,the later stage decreased and approached the before altitude level,gradually increased in the early stage of the pre-competition train stage,the S4 week was significantly increased,and the later stage decreased slightly.The WBC only increased 29.15% in the plateau training stage,and remained basically unchanged in the pre-competition training stage.CK,BU increased by 45.66% and 8.65% respectively after high altitude training,CK decreased 34.19%and BU increased 20.14% after pre-competition.In the two stages,both T and T/C decreased,and the T decreased significantly in the pre-competition stage(P<0.05),and C increased only in the pre-competition stage.(2)The change of HRV in different training stage In the early stage of plateau,the relative indexes of HRV increased,the HRV decreased during the upper cycle of G3 and the HRV on the intensity of G7 decreased.The relative indexes of HRV increased after plateau training and reached the peak value of the whole plateau training stage.In the pre-competition training stage,the HRV index of high intensity S5 weeks decreased,and the SDNN,RMSSD,SDSD,TP was at the lowest value of the whole pre-competition stage.The HRV decreased after the pre-competition training,which showed that the vagus nerve index decreased,the sympathetic nerve index increased significantly and the peak value of the whole pre-competition stage was reached.(3)Changes of Endocrine Indexes of ANS in different training stages During the first week of high altitude,the index of NO,ACH,CA increased,especially the CA increased significantly(P < 0.05)and ET-1 decreased significantly(P < 0.05).Recovery period after plateau training,compared with those before high altitude,the index of NO,ACH,CA increased and ET-1 decrease.the NO decreased36.02% at S5 week,and ET-1 increased significantly(P < 0.01).ET-1 decreased significantly(P < 0.05)at S7 week.ACH decreased significantly at S3,S5 week(P< 0.01)and rose significantly(P < 0.01)at S7 week.(4)Correlation between HRV and physical function status during different training stages There was a significant positive correlation between HRV and CK in altitude training stage(P<0.05)and a significant positive correlation between TP and CK(P <0.01).There was a significant negative correlation between VLF and C(P < 0.01)and a significant positive correlation between VLF and T /C(P < 0.05).significant positive correlation between SDNN,HF,LF and HB(P < 0.05)and significant negative correlation(P < 0.01)between TP and HB during pre-competition training.significant negative correlation Between SDNN,HF and C(P < 0.05),and significant positive correlation between HF and T / C(P < 0.05).Research conclusion:The change of HRV showed good consistency with the change of routine functional state evaluation index.At the early stage of high altitude winter training,the related indexes of sympathetic nerve activity of HRV response increased significantly,and the sympathetic / parasympathetic balance gradually recovered with the adaptation to training.The index of parasympathetic nerve activity of HRV was significantly decreased in the period of high intensity training before the competition,and gradually recovered after training adjustment.The above results suggest that HRV can be used as a non-invasive index to judge the physical function of athletes.It can accurately reflect the adaptability of athletes to the training load.