Study On Strength Trainability Of Preadolescent Children

Objective:Strength and muscle function are the cornerstone of all physical ability.Conditioning has become a mandatory test for Chinese professional Athletes nowadays,and the significant role of youth conditioning training has been reiterated.However,there is a lack of strength training research on preadolescent children.Considering the unique physiological character of this population,filling this void is indeed an urgent task.Hence,the objective of this study is to:1)Explore the strength trainability of preadolescent children(7～9 years old);2)Explore whether the improvement of muscle function can benefit other physical ability;3)Explore the safety of strength training among preadolescent children and,4)Provide some thoughts and theory for the practice of youth conditioning training.Method: Forty five amateur 7-9-year-old basketball players were randomly assigned to intervention group(INT)that performed two 7-week plyometric training block(Lower body and Upper body)and control group(CON)that continued regular training.The following tests were performed before,at middle and after the intervention: Seated Medball throw(SMT),Handgrip(HG),Push-Up test,40 s Curl-Up,CMJ,squat jump(SJ),standing long jump(SLJ),20 m sprint,505 test and sit-and-reach.Result:Group × time interactions were found for all parameters except for sit-and-reach.However,the effect size of 505 test imply that the change might not reach meaningful level in real life(d= 0.12 and 0.34).Post hoc test and effect size show that the improvement of upper body function(SMT,HG,Push-Up and Curl-Up)are greater after the second training block,and the improvement of lower body function(CMJ,SJ and SLJ)are greater after the first training block.Conclusion:14 weeks of plymotric training significantly increased 7-9-year-old children’s muscle function,but didn’t improve change-of-direction(505 test)and flexibility(sit-and-reach)performance.Plyometric training is safe for 7-9-year-old preadolescent children as long as there are suffice supervision.