Effects of Concurrent Endurance and Strength Training on Running Economy and Endurance Performance Indices in Distance Runners:A Meta-analysis

Objective:To evaluate the effects of concurrent endurance and strength training on running economy(RE) and endurance performance indices,such as body mass(BM),maximal oxygen uptake(<img id="6" type="formula" href="images/TYKX201909008_00600.jpg" display="inline" placement="inline" src="Detail/GetImg?filename=images/TYKX201909008_00600.jpg&uid=WEEvREcwSlJHSldSdmVpM3VCWENoekZpVHQzeWdJMlBJK0FyZ01SWC9Iaz0=9A4hF_YAuvQ5obgVAqNKPCYcEjKensW4IQMovwHtwkF4VYPoHbKxJw!!" style="height: 22px;"> <alt></alt>O_2max),time trial performance(TT)by using meta-analysis,and to provide strong evidences for training practice in long distance runners.Methods:A literature search was conducted by using the Pubmed,Springer,Embase,Sportdiscuss,Science Direct and CNKI databases. Two experienced reviewers were assigned to screen the articles and extract the data from included original studies independently. The PEDro scale was used to assess the methodological quality of the included studies. The heterogeneity,data combining,subgroup analyses,producing forest plot and sensitivity analyses,meta-regression,producing funnel plot,publication bias were assessed with Revman 5.3 and Stata 12.0,respectively. Results:17 studies in 15 articles were analyzed,a total of 276 well and highly trained runners who had no history of strength training were included. 10 studies were assessed to 6 points in PEDro quality scores,and 7 studies were ranged 4 to 5 points. The concurrent training had no significant effect on BM(P>0.05). Compared with power training,the heavy weight training and mixed strength training had a similar training effect on BM(P>0.05). The concurrent training had no effect on <img id="7" type="formula" href="images/TYKX201909008_00700.jpg" display="inline" placement="inline" src="Detail/GetImg?filename=images/TYKX201909008_00700.jpg&uid=WEEvREcwSlJHSldSdmVpM3VCWENoekZpVHQzeWdJMlBJK0FyZ01SWC9Iaz0=9A4hF_YAuvQ5obgVAqNKPCYcEjKensW4IQMovwHtwkF4VYPoHbKxJw!!" style="height: 22px;"> <alt></alt>O_2max,but the risk of deteriorating <img id="8" type="formula" href="images/TYKX201909008_00800.jpg" display="inline" placement="inline" src="Detail/GetImg?filename=images/TYKX201909008_00800.jpg&uid=WEEvREcwSlJHSldSdmVpM3VCWENoekZpVHQzeWdJMlBJK0FyZ01SWC9Iaz0=9A4hF_YAuvQ5obgVAqNKPCYcEjKensW4IQMovwHtwkF4VYPoHbKxJw!!" style="height: 22px;"> <alt></alt>O_2max could be higher in incremental volume training subgroup than that of equal volume training subgroup(P=0.08). Training level was considered to be a factor affecting the heterogeneity of the studies,the concurrent training was more effective for TT in highly trained runners than that of well-trained runners(SMD:highly trained subgroup-1.46-2.33,-0.60vs. well-trained subgroup 0.29-0.19,0.76,P<0.01). The concurrent training had a moderately and significantly beneficial effect on RE(SMD:-0.52-0.86,-0.18,P<0.01). The power training,heavy weight training and mixed strength training had a similar positive effect on RE(P>0.05),but the equal volume training was better than the incremental volume training(P<0.05),and the training duration of 9~12 weeks was better than 6~8 weeks(P<0.05). The training frequency of 2~3 times/week could be better than 1 time/week(P=0.05). Conclusions:The concurrent endurance and strength training could enhance RE in distance runners without BM gaining,and the improvement of RE could be more effective in improving exercise performance in highly trained runners. The training frequency of 2~3 times/week for 9~12 weeks could achieve an ideal training effect. The addition of strength training with a certain endurance training volume will attenuate the benefit effects on RE,and it will increase the risk of deteriorating the maximal aerobic capacity.