Effects Of Concurrent Resistance And Endurance Training On Body Composition,Muscle Strength And Cardiovascular Function In Healthy Young Men

Objective:Concurrent resistance and endurance training is a combined training method in which resistance training（RT）and endurance training（ET）are performed simultaneously,relevant studies have been conducted on body composition and muscle strength.However,the effects of acute concurrent training（CT）and eight-week CT on cardiovascular function in healthy young men remain unclear.In view of this,the effects of acute CT on cardiovascular function and eight-week CT on body composition,muscle strength and cardiovascular function of healthy young men were investigated using high intensity interval training（HIIT）and RT as control groups.Methods:A total of 39 healthy male university students conforming to the experimental requirement were selected from a university and randomly divided into HIIT group,RT group and CT group.Before the training,the morphological parameters of body,maximal oxygen consumption(VO_2max)and 1RM were determined.An acute training was performed 7 days later,followed by eight weeks of exercise training three times a week with a minimum interval of 48 hours every two times.In HIIT program,after 2min warm-up with 50W load,high intensity pedaling at 85%VO_2maxfor 1min,then low intensity pedaling at 35%VO_2maxfor 1min,alternating cycles of 10 groups,and pedaling at 50W load for 2min relaxation after exercise;RT scheme consisted of squat,bench press,hard pull and row.Four sets of repetitions were performed at 70%1RM,with 8-12 repetitions in each group.The interval was 60-90 seconds within the group and 2-3 minutes between the groups.The CT regimen consisted of 50%RT and 50%HIIT,with 2 groups of RT first and5 groups of HIIT 10 minutes later.Body composition,muscle strength,arterial stiffness[cardio-ankle vascular index（CAVI）],blood pressure,heart rate variability[standard deviation of normal R-R intervals（SDNN）,squares of differences between adjacent NN interval（RMSSD）,high frequency（HF）,low frequency（LF）,LF/HF],and cardiovascular biochemical indicators[transforming growth factor-β（TGF-β）,cardiac troponin（c Tn）,N-terminal pro-B-type natriuretic peptide（NT-pro BNP）]were measured before and immediately after acute single exercise and 48h after eight weeks of training.SPSS 26.0was used for statistical analysis.Firstly,K-S was used to test the normality of the data,Levene Text was used to test the homogeneity of variance,two-factor repeated measure analysis of variance was used for acute and 8-week data,then simple effect analysis was performed,paired sample T test was performed within each group,and univariate analysis of variance was used between groups.Correlation was tested by Pearson.Results:Acute training results:1.After acute training,systolic blood pressure was significantly increased in CT group compared with HIIT group and RT group（P<0.05）,but diastolic blood pressure had no significant change（P>0.05）.CAVI in both sides was significantly decreased（P<0.01）,and CT group was significantly lower than RT group（P<0.05）.2.After acute training,LF/HF in CT group was significantly increased compared with HIIT group and RT group（P<0.05）,while SDNN,RMSSD,HF and LF were significantly decreased（P<0.05）.3.After acute training,TGF-β,c Tn and NT-pro BNP were significantly increased in CT group compared with HIIT group and RT group（P<0.05）.Eight weeks of training results:1.After eight weeks of training,lean body mass was significantly increased in CT group compared with HIIT group and RT group（P<0.05）.The body fat percentage in HIIT group and CT group was significantly decreased（P<0.05）,but there was no significant change in RT group（P>0.05）.2.After eight weeks of training,the 1RM of squat in HIIT,RT and CT groups were significantly increased（P<0.05）,the 1RM of bench press,1RM of hard pull and 1RM of row in RT and CT groups were significantly increased（P<0.05）,but there were no significant changes in HIIT group（P>0.05）;The maximum strength improvement in CT group was significantly higher than that in HIIT group after training（P<0.05）.3.The VO_2maxin HIIT group and CT group were significantly increased（P<0.05）,but there were no significant changes in RT group（P>0.05）;The VO_2maxin CT group was significantly lower than that in HIIT group,but higher than that in RT group（P<0.05）.4.After eight weeks of training,systolic blood pressure and bilateral CAVI in HIIT and CT groups were significantly decreased（P<0.05）,but no significant changes were observed in RT group（P>0.05）;There were no significant changes in diastolic blood pressure in HIIT,RT and CT groups（P>0.05）.5.After eight weeks of training,SDNN and RMSSD in HIIT group and CT group were significantly increased（P<0.05）,HF in CT group was significantly increased（P<0.05）,LF/HF was significantly decreased（P<0.05）;LF in the three group,all indexes in the RT group and HF and LF/HF in the HIIT group was no significant change（P>0.05）.6.After eight weeks of training,NT-pro BNP in HIIT group and CT group was significantly decreased（P<0.05）,TGF-β,c Tn in the three group and NT-pro BNP in the RT group was no significant change（P>0.05）.Conclusion:1.Acute concurrent training,high-intensity interval training and resistance training can cause similar changes in cardiovascular function in healthy young men.2.The eight-week concurrent training had no interference effect,and compared with high-intensity interval training,it could improve the muscle strength of healthy young men better;Compared with resistance training,it can improve VO_2max,body composition and cardiovascular function in healthy young men.