Effects Of Complex Training On Musculoskeletal Fitness,Running Economy And Endurance Performance In Distance Runners

BackgroundWith the enhancement of national health awareness and the hot promotion of running events,more people have participated the long-distance running;both professional and amateur runners are committed to finding training methods to improve their long-distance running performance.In the past 10 years,maintaining maximum aerobic capacity while improving the musculoskeletal fitness of trainers through strength training for improving running economy and maximum running speed are new trends of long-distance running training.Complex Training(CT)is a combination training method that alternates performing heavy resistance exercises and plyometric exercises within one single session,resulting in great improvement on neuromuscular adaptation.Resistance Training(HRT)and plyometric training(PLY)are the most common strength training methods utilized for distance runners,improve running economy and maximum sprint speed.However,so far,there has not been a report on long-distance runners using the complex training to improve running performance.There is no comparative study on the effect of complex training,maximum strength and strength-endurance training to improve long-distance running performance.Based on this,the purpose of this study is to:1)explore the effects of complex training on skeletal muscle function,running economy,aerobic capacity,running biomechanical characteristics and running performance in professional long-distance runners and amateur marathon runners.2)Compare the effects of CT,HRT and strength-endurance training in improving the above indicators.3)Exploring the physiological and biomechanical mechanisms of CT to improve the long-distance running performance.MethodsThis thesis contains two longitudinal experimental studies to investigate the effects of 6 and 8 weeks of complex training on the running performance in recreational marathon runner and professional distance runners.In the first part of the study,a total of 38 recreational marathon runners completed the entire experiment.After 2 weeks of preparation,the participants mastered the strength training technique and were familiar with the test procedure,and then performed body composition(body weight,body fat,fat free etc.),musculoskeletal fitness(1RM[one maximum repetition]strength,squat jump[SJ],counter movement jump[CMJ],drop jump[DJ]and leg stiffness),12-14km·h-1 running economy,maximum oxygen uptake and 10-km as pre-test.Based on the pre-test results,the participants were divided into three groups according to gender,age and VO2max level and 10km running time:complex training group(CTG,N=13),who performed 70-85%1RM heavy strength training and plyometrics training;Maximum strength group(MSG,N=13)who performed 70-85%IRM heavy strength training;Control group(CG,N=12).who performed 30-40%1RM strength-endurance training.During the intervention training phase,the subjects maintained the normal endurance training arrangements and added twice a week,totally 6 weeks of strength training.After the 6 weeks training intervention,all participants completed a post-test(identical to pre-test)to investigate the training effects between groups.In second study,28 well-trained male distance runners performed body composition(body weight body fat,fat free etc.),musculoskeletal fitness(1RM[one maximum repetition strength],counter movement jump[CMJ],drop jump[DJ]),running biomechanical(lower limb stiffness,contact time,ground reaction force,sagittal angle change of the lower limbs and vertical oscillation of the center of mass),12-16km·h-1 running economy,blood lactate concentration,maximum oxygen uptake,50-m sprint and 5-km as pre-test.Based on the pre-test results,the participants were divided into three groups according to the age,VO2max level and 50km running time:complex training group(CT,n=10),who performed 80-85%1RM heavy strength training and plyometrics training;Heavy resistance training group(HRT,n=9)who performed 80-85%1RM heavy strength training;Control group(CON,n=9),who performed 40%1RM strength-endurance training.In addition,participants took the same endurance training during the intervention,including long-distance running with 70-75%maximum heart rate(HRmax)and interval running with 90-95%HRmax.After the 8 weeks training intervention,all participants completed a post-test(identical to pre-test)to investigate the training effects between groups.ResultsIn the first study,after 6 weeks of intervention,all three groups did not change the body composition,and significantly increased 1RM strength(p<0.001).Both the CTG and MSG groups had significant improvements in 1RM strength,SJ,CMJ and DJ height and leg stiffness(P<0.001).There was no significant difference in the CG group.After intervention,the CTG group had a significant improvement in EUR(3.87%,P=0.001),and MSG group had a significant reduction in EUR(-3.86%,P=0.001).There were no significant changes in VO2max in the three groups compared to the pretest,but both the CTG and MSG groups showed a significant increase in vVO2max after intervention(P<0.001).For the running economy,all three training groups showed significant improvement in 12 km·h-1 RE(p<0.05),both the CPX and HRT groups had significant improvements in 14km·h-1 RE(P<0.001).There was no significant difference in the CON group.All three training groups showed significant improvement in 10-km running performance.In the second study,after intervention,both the CPX and HRT groups had significant improvements in 1RM strength,CMJ height,Peak Power,and RFD(P<0.05).Only the CPX group exhibited significant increases in drop jump height and reactive strength index(p<0.001).For biomechanical test,both the CPX and HRT groups had significant improvements in 14km·h-1 leg stiffness,14 and 16 km·h-1 vGRF.At high speed running test,the CT group showed significant improvement in 16km·h-1 leg stiffness,and a reduction in the contact time,knee angle of middle land phase and vertical oscillation of the COM,but not for the CON group after intervention.For running economy,all three training groups showed significant improvement in 12 km·h-1 RE(p<0.05),both the CPX and HRT groups had significant improvements in 14km·h-1 RE.Only the CPX group exhibited significant improvement in 16 km·h-1 RE and reduction of blood lactate concentration(BLa)at the speed of 16 km·h-1(-40.80%,p<0.001)between pre-and post-test.Both the CPX and HRT groups had significant improvements in 50-m sprint and 5-km running performance.There was no significant difference in the CON group.Conclusion1.Adding 6-week complex training to recreational marathon runners' endurance training can significantly improve musculoskeletal fitness such as maximum strength,jump height,reactive strength and leg stiffness without affecting body composition and VO2max.Complex training can also improve the12,14km·h-1 RE and velocity at VO2max and 10km running performance.2.In addition to the EUR,the maximum strength training and complex training have similar effects on improving the musculoskeletal fitness,running economy and running performance in recreational marathon runners.3.Adding 8-week complex training or heavy resistance training to professional distance runners' endurance training can significantly improve 1RM,CMJ jump height,peak power and RFD;at the same time,it can also increase 12 and 14km·h-1 running economy,50-m sprint and 5-km running performance.4.Compared with the heavy resistance training and strength-endurance training,complex training has better effects on improving the power and reactive strength.This can reduce vertical oscillation of the COM while improving their landing and propelling efficiency,and reduce the oxygen consumption and blood lactic acid concentration during the 16 km·h-1 speed running.Therefore,complex training is superior to maximum strength and strength-endurance training for improving endurance performance in professional distance runners.5.The complex training can simultaneously involve the benefits of heavy resistance training and plyometrics training,and enhance the running performance of professional and recreational runners from the physiological and biomechanical aspects.