Effects Of Different Supplementation Groups On U-18 Man's Footballer's Body Composition,strength And Partial Biochemical Indexes In Pre-competition Preparation Period

Objective: To evaluate the effects of three different nutritional supplements on the changes of body composition,exercise capacity,and some blood parameters of man's U-18 footballers during pre-competition preparation,and to provide valuable reference materials for the scientific nutrition and monitoring of related sports training.Methods: Twenty-four male U-18 soccer players were recruited for the eight-week pre-match preparation of athletes(CHO group),supplemented with sugar and whey protein concentrate powder(CHO+WPC group),supplemented with sugar and whey protein isolate powder(CHO+WPI group).The CHO+WPC group and the CHO+WPI group supplemented the protein by 2g/kg body weight standard every day according to the footballer's physical reserve period(including strength training,twice a week,Wednesday and Saturday),and the CHO group supplemented the corresponding calories of sugar.The differences in body composition,Wingate anaerobic work,maximum strength,and blood physiological and biochemical indexes before and after the trial were compared among the three groups of athletes.Results:(1)Body weight and body composition: Body weight of CHO group decreased significantly after the test,while body weight of the other two groups did not change significantly;body weight gain effects of CHO+WPI group and CHO+WPC group were significantly higher than those of CHO group;The fat content in the WPI group and the CHO+WPC group was significantly reduced,and the lean body mass was significantly increased in the CHO+WPI group.(2)Exercise capacity: There was no difference between the maximum force of bench press,half squat,shoulder push and deadlift before and after each trial,and the increase in scores of semi-and deadlift in CHO+WPI group was significantly higher than that in CHO group;Peak power and relative peak power values did not change significantly before and after the tests,and absolute average power and relative average power were significantly higher in all three groups than before the test.(3)Relevant biochemical indicators: Serum CK levels in the CHO+WPI group decreased significantly after the trial,and there was no significant change in the other groups.There was no significant change in blood urea levels before and after the experiment;serum testosterone levels did not change significantly in each group before and after the test.There was no significant difference between the groups;serum cortisol was significantly reduced in each group after the test;T/C values in each group were significantly higher than before the test,and there was no difference in the T/C change value(difference)between the groups.Conclusions:(1)Supplementing WPC and WPI in the pre-preparation period can effectively combat the weight loss caused by exercise training,among which WPI supplementation has a positive effect on increasing lean weight.(2)Supplementing CHO + WPI in improving stepping on the man's footballers and the greatest power of big muscle group has a promoting effect,simple carbohydrate supplement and complement CHO + WPC has to maintain the pre-match preparation stepping male footballers big muscle group's largest power;There was no significant difference in anaerobic capacity between different nutrient supplements.(3)Supplementing CHO+WPI during the preparation period can reduce the serum CK level of U-18 man's footballers;Supplementing CHO,CHO+WPC and CHO+WPI is conducive to maintaining serum testosterone levels,lowering cortisol levels,relieving muscle breakdown and reducing exercise fatigue.