Evaluation of Left Ventricular Myocardial Work Quantitatively by Pressure-strain Loop in Young Strength Athletes With Different Heart Rates

Abstract

Objective: The present study aimed to investigate the difference in left ventricular (LV) global and regional myocardial (MW) of strength athletes with different heart rates (HR) through non-invasive LV pressure-strain loop (PSL) and further address the effect of athlete’s heart rate variability on the LV systolic function.Methods:Fifty young professional wrestlers were collected randomly and divided into two groups in accordance with their different HR: the low HR (45~60 bpm, n1=25) and the high HR (60~80 bpm, n2=25). Thirty individuals with gender- and age-matched healthy volunteers served as controls (n3=30). Global and regional MW parameters were evaluated using LV-PSL derived from speckle tracking echocardiography (STE) and brachial artery pressure, and then compared between the above three groups.Results:The indicators of global and regional MW did statistically significantly differ between the athlete and control groups. Peak strain dispersion (PSD) and global myocardial wasted work (GWW) increased while global myocardial work efficiency (GWE) reduced in LHR and HHR groups compared with the control group, and global myocardial work index (GWI), global myocardial constructive work (GCW), global longitudinal strain (GLS) decreased in LHR group (P＜0.05). In comparison to the LHR group, GWI, GCW, GWW, PSD increased in HHR group and GWE reduced (P＜0.05). According to the regional MW analysis, the mean regional myocardial work index (RMWI) increasing gradually from basal to apical levels were similar across the three groups and regional myocardial work efficiency (RMWE) did not. Multiple linear regression analysis indicated that the HR, posterior wall thickness (PWT), interventricular septal thickness (IVST), GLS, and PSD were correlated with GWE (b’= -0.247, -0.390, -0.370, 0.340, and -0.554, respectively, P＜0.05).Conclusions:The LV contractile performance was more impaired in young strength athletes with high heart rates and PSL can be used to assess LV GMW and RMW quantitatively and accurately in reflecting LV systolic function.

The Study of the Effect of Variation of Human Parameters on the Walking Speed Based on Simulations

“…The correlation analysis shows that the leg length plus foot height parameter has a high positive correlation with walking speed at the 0.01 level (r = 0.4 m, p = 0.970; r = 0.41 m, p = 0.991; r = 0.42 m, r = 0.982), which is the same trend as the experimental research conclusions of Huali [5]. In the measured data of Huali [6], the range of leg length plus foot height is 0.390-0.456 m. In its evaluation indicators, this parameter is used as a length factor in the first level index, with a weight of 42%. It can be seen that the leg length plus foot height parameter is a key factor to be considered in the selection of race walking athletes.…”

“…In Huali's research, five indicators, including leg length plus foot height, (weight/height) * 1000, ankle circumference/lower limb length, foot height, (leg length plus foot height)/lower limb length, were used as indicators for the evaluation model of race walking athletes' body shape, and comprehensive scoring criteria were given respectively, and the athletes' body shape was scored. Among them, the four indicators of leg length plus foot height, (weight/height) * 1000, foot height, and (leg length plus foot height)/lower limb length are all rated high by those with high values, while those with high comprehensive ratings have a large proportion of high athletic performance, that is, the values of the above indicators are positively correlated with athletic performance [6].…”

“…According to national standard data, the average value of leg length plus foot height for adult women in China is 0.41 m. In the measured data of Huali, the parameter range is between 0.39-0.45 m. To cover the range of experimental samples, the simulation calculation of this study sets the parameter change range to 0.38-0.48 m [6].…”

“…Chen Tuyu conducted a kinematic analysis of the walking techniques of Chinese athlete Wang Kaihua and compared his differences with international elite athletes [5]. Hua Li determined five indicators, including leg length and foot height, weight/height * 1000, ankle circumference/lower limb length, foot height, (leg length and foot height)/lower limb length, as the basis for the evaluation model of race walking athletes by measuring and analyzing the physical parameters of 50 female race walking athletes, and the comprehensive scoring criteria have a high correlation with the athletes' performance grades [6].…”