The Influence Of Carbohydrate-protein Ingestion On Androgens Metabolism Of Male Strength Athletes During Resistance Training

Purposes:Strength quality is the most important physical quality of athletes. Resistanceexercise is important training method to improve strength quality. Nutritionalsupplement methods are used in training practice to promote fatigue recovery afterresistance exercise and improve the capability of strength. A lot of existing studiesfocused on the influence of athletic ability after supplementing pure carbohydratedrinks. But the research is less on carbohydrate plus protein drink to promote sportperformance. The latter nutrient method is preferred in the field of international sportsnutrition recently. The study is designed to research the influence of the carbohydrateplus protein drinks on the sports performance and fatigue recovery to the malestrength event athletes during resistance exercise by observing the effect ofcarbohydrate plus protein supplementation on androgen metabolism after resistanceexercise.Methods:In a bout resistance exercise, an acute experiment，18male strength eventathletes as the subjects were divided into three groups randomly. They arecarbohydrate plus high-protein group (group HP, CHO: PRO=3:1), carbohydrateplus low-protein group (group LP, CHO: PRO=6:1) and carbohydrate-only group(group C).Total volume of beverage is15ml·kg-1, the CHO concentration is8%，30minutes before, in process and30minutes post exercise, intake volume is6ml·kg-1,3ml·kg-1, and6ml·kg-1respectively. The activity of resistance exercise is squat andbench press in turns.4sets of8repetitions were completed at70%of1-RM for squat with60-second rest between each set and90-second rest after the fourth set. After that,4sets of squatswere performed at50%of1-RM with the same rest time between each set and150-second restafter the fourth set. And then, bench press exercises were followed with the same sport load as thesquat exercises. The venous blood was drawn immediately before and after exercise,3hours after exercise and the next morning after exercise respectively. The urine was also collected at rest and after exercise and the next morning after exercise. ANOVAof repeated measurement was used to compare intra-group variables in fixed timepoints. One-way ANOVA was used to compare inter-group variables.In3-week resistance exercise, a chronic experiment，10male Greco-romanwrestling athletes as the subjects were divided into three groups randomly. They werecarbohydrate plus high-protein group (group HP), carbohydrate plus low-proteingroup (group LP) and carbohydrate-only group (group C). The quantity and time pointfor nutritional supplement is the same as the acute experiment. All subjects completedthe instrument resistance training3times a week. The training activities were benchpress, squat, pull up and dead left. And the exercise load was90%of1RM,6sets×4reps,2.5mins rest between sets; The others session was cushion training. The chronicexperiment was designed by cross-over trial design. Each group received the3-weekintervention and2-week wash-out to observe the absolute strength and specialstrength before and after each intervention period, the body composition with emptystomach, blood androgen and urine androgen ect.. Paired samples test was used tocompare intra-group differences.3-period cross-over analysis of variance was used tocompare inter-group difference.Results:In the acute experiment:(1) Serum free testosterone (FT) in HP group droppedsignificantly (P<0.01) immediately after exercise, increased (P<0.05)3h afterexercise, and then decreased (P<0.05) next morning after exercise. FT in LP groupdropped significantly (P<0.05) immediately after exercise, increased (P<0.05)3hafter exercise, and then decreased significantly (P<0.01) the next morning afterexercise. FT in Group C had no change immediately and3h after exercise, butdropped sharply（P<0.05）the next morning after exercise. In comparison amonggroups, FT in group C is significantly higher than that in HP, LP group afterimmediately exercise,3h after exercise and the next morning after exercise.(2) Sex hormone binding globulin (SHBG) in HP and LP group has samevariation trend. There is no changed immediately after exercise. but it droppedsignificantly (P<0.05)3h after exercise, subsequently increased (P<0.05) next morning after exercise. SHBG in Group C dropped significantly immediately afterexercise (P<0.01) and3h after exercise (P<0.05), and then increased the nextmorning after exercise. By comparison among groups, the group C is obviously lowerthan that in HP and LP group the next morning after exercise.(3) Urine androgens increased immediately after exercise, and then declined thenext morning except5α-diol and5β-diol of HP group, which increased significantly(P<0.05) the next morning after exercise.In chronic experiments:(1) Sports performance: absolute strength in HP groupincluding bench press, squats and dead left increased significantly (P<0.01). Absolutestrength in LP group including squats and dead left increased significantly (P<0.05).Bench press increased, but there was no significant change (P>0.05). Absolutestrength in C group including bench press, squats and dead left increased, but therewas no significant change (P>0.05). In addition, there was no significant differenceamong groups (P>0.05).(2) In the comparison of body composition there was no significant difference ingroups except significant increase in muscle mass of HP group (P<0.05).(3) There is no significant change in urine androgens among3groups except thesignificant increase of5α-diol in HP group（P<0.05）.(4) Serum testosterone and the values of urine epitestosterone andetiocholanolone corrected by creatinine had significant correlation (P<0.01) and thecorrelation coefficient is0.516and0.491respectively.Conclusions:During the process of a bout resistance exercise, HP (CHO: PRO=3:1) and LP(CHO: PRO=6:1) beverage intake causes serum sex hormone-binding globulinlevels in recovery period significantly higher than the intake of C (pure carbohydrate)Beverage. The intake of carbohydrate plus protein drinks can promote the bodytissues assimilation of male strength athletes after resistance exercise and improve thesports performance of male strength athletes.HP beverage intake during a bout resistance exercise can change the androgenicmetabolic profile of male strength athletes, while LP and C beverage intakes do not show any change at all. HP beverage intake can promote testosterone todihydrotestosterone conversion of male strength athletes after a bout resistanceexercise and relieve fatigue after exercise and improve sports performance.HP beverage intake during3-week resistance exercise can change the androgenicmetabolic profile of male strength athletes. However, LP and C beverage intakes donot show the change. HP beverage intake can promote testosterone todihydrotestosterone conversion of male strength athletes during3-week resistanceexercise，relieve fatigue after exercise and improve sports performance of the athletes.Owing to the non-invasive and easy sampling， epitestosterone （ET） andetiocholanolone (Etio) in the urine can be employed as a new sport monitoring indexfor the long-term and longitudinal supervision to the training of male strength athletes.