high - intensity exercise can cause temporary fatigue due to atp depletion and excessive 
 production of hydrogen ions and ammonia .
in addition , intense exercise causes muscle tissue damage 
 that gives rise to an inflammation response . in these individuals , a higher frequency of 
 lesions , chronic inflammatory processes , reports of muscle pain , and discomfort are 
 observed , and these effects harm athletic performance1 .
exercise with high energy consumption or a high repetition rate , 
 such as rowing , can release intracellular proteins in the blood , such as ck , lactate , and 
 cytokines , independent of the nature of the muscle damage .
activation of the inflammatory 
 mechanism involves the synthesis and release of pro - inflammatory mediators such as 
 cytokines2 .
the mechanisms involved , 
 however , have not been fully determined and seem to be multifactorial , including such things 
 as training and nutritional status .
bcaa is the only amino acid metabolized in skeletal muscles , and its effects as a precursor 
 for glutamine synthesis have been studied broadly . regarding the impacts of bcaa 
 supplementation ,
studies have been reported with contradistinctive results indicating that 
 the bcaa acts as a major energy substrate in the muscle along with the increased 
 contribution of fat as an energy source in accordance with the exhaustion of carbohydrates 
 during long periods of exercise3 while 
 also indicating that the increase in the degree of oxidation of bcaa triggers a gradual 
 decrease in intermediates in the tca cycle , which could cause fatigue due to exhaustion of 
 energy4 . however , glutamine is a sort of 
 amino acid found abundantly in human skeletal muscles and blood .
it maintains the acid - base 
 balance while acidosis occurs and acts as a nitrogen precursor to synthesize nucleotides , as 
 a fuel in muscles , and as a direct controller for the synthesis and decomposition of 
 protein5 .
additionally , glutamine has 
 been reported to be an important fuel for immunostimulatory effects6 .
the glutamine level , however , is lower after exhaustive 
 exercise , and its provision as an oral supplement after exercise has beneficial effects on 
 infections in athletes7 .
furthermore , 
 athletes experiencing discomfort from overtraining exhibit lower levels of plasma glutamine . 
 thus , glutamine supplementation is very important for growing juvenile athletes .
however , 
 several studies of oral supplementation of substantial amounts of glutamine in athletes have 
 failed to demonstrate enhancements in immune function or performance parameters .
recently , 
 however , cruzat et al . demonstrated that a solution containing glutamine represents an 
 effective means of supplementing rats with glutamine , attenuating inflammation markers and 
 plasma ck levels induced by intense exercise8 . in the present study , we investigated the effects of supplementation with bcaa and 
 glutamine on blood concentrations of lactate , phosphorus , ammonia , ck , and cytokines in 
 juvenile athletes subjected to maximal intensity rowing exercise .
five male juvenile athletes ( mean age ( sd ) , height , weight , and percent body fat were 
 17.21.1 y , 176.22.9  cm , 71.712.2  kg , and 17.75.6% ) were included in this study .
prior to 
 participation , all subjects provided written informed consent in compliance with the 
 appropriate institutional review board at the university .
the athletes were allowed to drink and eat normally but received a placebo , bcaa , or 
 glutamine for 7 days before the test .
bcaa ( spomax , seoul , republic of korea ) was given 
 three times a day ( 25% valine , 50% leucine , 25% isoleucine , 3.15  g / day ) , and l - glutamine 
 ( optimum nutrition , aurora , il , usa , 6  g / day ) was given three times a day .
blood samples 
 were collected from the antecubital vein on the day of testing while resting before the 
 test , immediately at the end of test , and 30  min after the test .
all tests were conducted 
 with a 1-week interval to eliminate the potential effects from remaining dosages .
the rowing test was conducted with an indoor rowing machine ( concept2 , morrisville , vt , 
 usa ) 3 times each for supplementation with the placebo , bcaa , and glutamine .
all the 
 subjects performed a 2,000  m ( olympic single scull race ) race at their own individual 
 maximum paces ( 4245 pace for 0m~250 m , 40 pace for 250m~500 m , 3638 pace for 500m~1,500 m , 
 and over 42 pace for 1,500 m~2,000 m)9 .
the blood lactate concentration was measured using an accutrend plus system ( roche , 
 indianapolis , in , usa ) .
drops of blood were collected from fingertips washed and dried 
 completely using a blood gathering device .
reagent paper was then inserted into the device 
 for 60 seconds , and measurements were obtained thereafter .
the blood phosphorous 
 concentration was analyzed using a hitachi 747 analyzer ( hitachi , tokyo , japan ) by applying 
 the uv method .
a 0.5ml sample of centrifuged blood serum was prepared to develop the color 
 by applying a reagent containing sulfuric acid , 250l of added surfactant , and ammonium 
 molybdate for measurement with a dominant wavelength of 340  nm and sub - wavelength of 505  nm . 
 the blood ammonia concentration was analyzed using a shimadzu cl-750 spectrophotometer 
 ( poli , milano , italy ) by identifying the reaction . at first , 1ml of blood was added into 2ml 
 of deproteinization solution to remove enzymatic activity , which could create blood ammonia , 
 and the supernatant was separated after centrifugation .
then 4% of phenol , 0.015% of 
 nitroprusside salt , and 4.1% of koh were added to make it alkaline , and the color was 
 developed using a reagent containing 28% of potassium carbonate and 3% of potassium chlorate 
 for measurement at a wavelength of 630  nm .
ck activity was analyzed with a hitachi 7600 - 110 
 chemistry analyzer ( hitachi , tokyo , japan ) by applying the uv method .
eight microliters of 
 blood serum was separated to develop the color at 37  c using 75l of reagent r2 and 300l 
 of regent r1 , and it was measured at a dominant wavelength of 340  nm and sub - wavelength of 
 405  nm .
the biochemical analyses for il-6 , il-8 , and il-15 were conducted with the bio - plex pro 
 magnetic cytokine assay ( bio - rad , hercules , ca , usa ) , and it was directly analyzed using a 
 human serum cytokine kit .
all components were stored at 4  c , and a multichannel pipette , 
 reagent reservoir , plate shaker , and vacuum manifold were prepared for the test . the 
 standard , cytokine , and magnetic beads were each diluted , and 50l of diluted standard and 
 diluted samples were sprayed into each of the wells and washed 3 times after 30 minutes of 
 incubation in the shaker .
then , 50l of prepared detection antibody were sprayed into each 
 well and washed 3 times after incubation for 30 minutes in the shaker ; using the assay 
 buffer , 50l of prepared streptavidin - pe were sprayed into each well and washed 3 times 
 after incubation for 10 minutes in the shaker .
finally , 125l of assay buffer were sprayed 
 into each well and shook for 30 seconds and the states of calibration and washing were 
 analyzed using the bio - plex manager software ( bio - rad , hercules , ca , usa ) .
data were analyzed using the spss 18.0 for windows computer software package ( spss , 
 chicago , il , usa ) .
all the data were tested for normal 
 distribution using the shapiro - wilk test .
comparisons of variables between the groups and 
 times of the test were analyzed by two - way mixed model repeated measures anova . in the case 
 of a significant group and time main effect , two - tailed post hoc analysis
the alpha level was set a priori to p=0.05 to determine statistically 
 significant differences .
the blood lactate concentration varied at each stage ( p<0.05 ) but was not significantly 
 different between groups .
the blood lactate concentration at the end of exercise appeared 
 higher in all 3 groups compared with in the resting stage ( p<0.05 ) , and those of all 3 
 groups in the recovery stage were lower than those at the end of exercise . the blood 
 phosphorous concentration differed stage by stage ; however , the differences between groups 
 were insignificant ( p<0.05 ) .
the blood phosphorous concentrations of the 3 groups at the 
 end of exercise were all higher than those in the resting stage ( p<0.05 ) , and those of 
 the ps group in the recovery stage were not significantly different from those at the end of 
 exercise .
but the concentrations in the bs and gs groups in the recovery stage appeared to 
 be lower than those at the end of exercise ( p<0.05 ) .
the blood ammonia concentration 
 showed different levels in each stage but also did not differ significantly between groups . 

the blood ammonia concentrations in the 3 groups at the end of exercise all appeared to be 
 higher than those in the resting stage ( p<0.05 ) , and those of all 3 groups in the 
 recovery stage appeared to be lower than those at the the end of exercise .
the blood ammonia 
 concentration also varied stage by stage ( p<0.05 ) , but it also did not differ 
 significantly between groups .
the level of blood ck activity at the end of exercise appeared 
 higher in all 3 groups than in the resting stage ( p<0.05 ) , and from the levels of the ps 
 and bs groups in the recovery stage were not significantly different from those at the end 
 of exercise ; however , the level of the gs group appeared to be lower than that at the end of 
 exercise ( p<0.05 ) ( table 1table 1 .
blood fatigue factorsitemsgrouprestingend of exerciserecoverylactate ( mmol / l)ps2.261.098.282.92 * 4.941.79*bs1.660.439.243.15 * 6.281.12*gs2.300.3710.540.82 * 4.421.05*phosphorous ( ug / dl)ps4.100.775.620.28 * 4.420.39bs4.520.855.540.46 * 4.360.52gs3.960.445.680.41 * 3.400.27ammonia ( mg / d)ps88.8031.99335.8085.37 * 123.0056.32bs111.0024.24418.0060.74 * 165.8057.01gs129.6026.17430.80102.32 * 119.2025.44ck ( iu / l)ps214.2078.61240.4086.91 * 227.4074.74bs217.4050.04258.0062.72 * 235.8051.09gs203.2044.40222.6045.13 * 190.2042.17meansd .
ps , placebo supplementtation ; bs , bcaa supplementtation ; gs , glutamine 
 supplementation . *
ps , placebo supplementtation ; bs , bcaa supplementtation ; gs , glutamine 
 supplementation . * p<0.05 vs. resting ;  p<0.05 vs. end of exercise the results regarding the variation in the blood cytokine concentrations are illustrated in 
 table 2table 2 .
blood cytokinesitemsgrouprestingend of exerciserecoveryil-6 ( pg / ml)ps21.7020.4624.7610.5818.601.14bs14.106.5324.0210.6115.366.27gs21.767.6322.127.5916.686.00il-8 ( pg / ml)ps25.3010.3534.168.0829.164.02bs27.148.3730.767.0824.229.78gs26.125.2125.915.0923.826.91il-15 ( pg / ml)ps24.266.4242.6624.04 * 34.9616.95bs24.266.4241.9821.89 * 19.065.56gs21.367.0729.604.8728.5010.63meansd .
ps , placebo supplementation ; bs , bcaa supplementation , gs , glutamine 
 supplementation . * p<0.05 vs. resting ;  p<0.05 vs. end of exercise . il-6 and il-8 showed no significant difference among the groups and stages . 

il-15 showed differences between stages ( p<0.05 ) , but the differences between groups were 
 not significant .
the blood il-15 concentrations of the ps and bs groups at the end of 
 exercise were different from those in the recovery stage ( p<0.05 ) , but there was no 
 significant difference between these stages in the gs group . in the recovery stage ,
the bs 
 group alone appeared lower than at the end of exercise ( p<0.05 ) .
ps , placebo supplementation ; bs , bcaa supplementation , gs , glutamine 
 supplementation . * p<0.05 vs. resting ;  p<0.05 vs. end of exercise
the enhancement of exercise performance for sports is deeply related to the capability to 
 generate anaerobic atp continuously along with delaying fatigue . in general , the degree of 
 fatigue depends on external factors ( such as exercise intensity , exercising period , etc . ) 
 and internal factors ( such as muscle mass , muscle fiber type , energy storage , etc . ) , and the 
 drop in muscle contraction is closely related to the stimulation of fatigue - triggering 
 metabolites such as lactate , phosphorous , and ammonia10 .
thus the proper supply of ergogenic aids can play a critical role 
 for the enhancement of exercise performance11 .
bcaa , an amino acid that can be mobilized in the skeletal muscles , is a nutritive substance 
 that can supplement the energy and help anabolism .
studies on application of bcaa to 
 minimize fatigue substances along with supplementation of required energy sources during 
 long periods of high intensity exercise have been conducted . however , there are 
 disagreements concerning the results from those studies . some positive results of studies on 
 bcaa application showed that enhancement of exercise performance through an increase in the 
 internal concentration of bcaa led to enhanced atp resynthesis and that facilitated the 
 anabolic hormone release to stimulate the synthesis of myoproteins improved the power of the 
 muscles .
glutamine is an amino acid found in abundance in the human muscles and blood plasma , and it 
 is considered to be essential for proper immune function because it supplies energy for 
 nucleotide biosynthesis . it was reported that in statuses of fasted or prolonged exercise or 
 recovery period followed by high intensity exercises the levels of plasma glutamine 
 dropped12 . also , the stressed states 
 caused by exercises demand an increased amount of glutamine for gluconeogenesis , and thus 
 the amount of plasma glutamine is rapidly exhausted .
thus , ingesting a 
 proper amount of glutamine would be critical , especially for juvenile athletes in the 
 growing stage . from the results of analyses conducted in this study ,
the blood lactate concentration , one 
 of the fatigue factors , showed differences at each stage ; however , those were indifferent to 
 each group that the glutamine supplementation appeared to be ineffective in reducing the 
 level of lactate stimulation during the recovery stage .
the rate of lactate production 
 exceeds the rate of removal during high - intensive exercise .
the stimulated lactate 
 facilitates acidosis and suppresses the enzymatic activation related to other metabolism and 
 glycolysis , which impedes atp synthesis and eventually leads to fatigue .
according to the 
 results of one study , glutamate transformed into other intermediates in the tca cycle and 
 the carbon skeleton of -ketoglutarate , and the glutamate concentration decreased rapidly 
 along with the reduction in glutamine13 . 

eventually , this would cause trouble in energy supply due to the reduction in intermediates 
 in the chained tca cycle14 .
moreover , 
 since the majority of carbon skeletons required for glutamine synthesis are derived from 
 glycogen or glucose in the muscle , the glycogen saved for glutamine synthesis might be 
 exhausted rapidly along with the practice of exercise .
the link between carbohydrate 
 metabolism and glutamine formation is closely connected to the level of postexercise plasma 
 glutamine , so synthesizing and maintaining the intermediates in the tca cycle by supplying 
 glutamine would decrease the lactate stimulation , giving positive effects to athletes ; 
 however , such effects were not clearly observed in this study . in the recovery stage ,
the 
 level of the glutamine supplementation group was the lowest among the groups , and the 
 difference was not statistically significant , probably due to an insufficient number of 
 subjects .
an increase in phosphorous , which is another fatigue substance , decreases the ratio of 
 cross - bridges in muscle fibers , and hinders the catalysis of atpase , and hydrogen ion 
 stimulation would form an inorganic phosphate ( h2po4 ) , 
 which leads to a decrease in power eventually .
the results of our analysis showed that the 
 levels of blood phosphorous in the bs and gs groups in the recovery stage were decreased 
 significantly compared with at the the end of exercise ( p<0.05 ) .
the results of the 
 present study showed that the phosphorous concentrations in the bs and gs groups were 
 significantly lower than that in the ps group at the end of exercise .
as discussed 
 previously , it was presumed that the bcaa or glutamine could have contributed in maintaining 
 the intermediate energy substrate in the tca cycle , which enabled the preservation of atp 
 that might have reduced the creation of inorganic phosphates .
the magnitude of amino acid metabolism may increase due to sharp rise in the level of blood 
 ammonia during high - intensity exercise , but the majority of the increase in ammonia during 
 the high - intensity exercise is created in the pnc cycle to maintain the total amount of 
 adenine nucleotides ; thus , the amount of ammonia created by amino acid metabolism is 
 estimated to be slight15 .
glutamine may 
 discharge nh4 through glutaminase catalysis in the oxidative 
 deamination of protein or may transform itself into glutamine by accepting the 
 nh4 from glutamate , and this role of ammonium ions is crucial in 
 amino acid metabolism .
problems with internal energy supply could be triggered by conditions 
 involved with inactive metabolites , hypoxia , stresses and dietary restriction .
the level of 
 glycogen is decreased by high - intensity exercise along with the decrease in the level of 
 -ketoglutarate which is the intermediate in the tca cycle .
glutamate also decreases in 
 accordance with the decrease in -ketoglutarate , which lowers the creation of glutamine , and 
 accordingly , the increase in ammonia from by the exercise hinders glutamine transformation 
 through the glutamine synthetase reaction ; eventually the increased level of ammonia would 
 trigger central fatigue and degrade exercising capability . in this study
, it was not 
 possible to identify the effects of internal bcaa presumed to be decreased by the exercise 
 and glutamine supplementation because the observed ammonia concentration among the groups 
 and per stage did not differ significantly from each other .
the ck , an enzyme decomposing creatine phosphate to generate anaerobic atp during 
 high - intensity exercise , is closely related to energy metabolism and is used as a marker for 
 tissue damage due to exercise stresses .
the results of the present study showed that the 
 levels of ck in the gs group at the end of exercise and in the recovery stage were lower 
 than those in the ps and bs groups , which might represent the effects of energy 
 supplementation from glutamine supply , which activated as a fuel in the muscle and as a 
 nitrogen precursor for nucleotide synthesis ; it could also be presumed that there was a 
 positive effect in protecting against tissue damage due to exercise stresses .
intensive exercise not only causes fatigue but also causes tissue damage triggering 
 inflammatory responses and changes in cytokines . until now ,
pro- and anti - inflammatory 
 cytokines have been considered part of the acute phase response to an infection or tissue 
 injury16 .
il-6 has been classified as a pro- and anti - inflammatory 
 cytokine , and recently , its main anti - inflammatory effects have been a concern .
il-6 
 directly inhibits the expression of tnf- and il-1 , and furthermore , il-6 is a potent 
 inducer of the il-1 receptor antagonist ( il-1ra ) , which exerts anti - inflammatory activity by 
 blocking il-1 receptors and thereby prevents signal transduction of pro - inflammatory 
 il-116 .
some studies have shown that 
 several cytokines can be detected in plasma during and after strenuous exercise17 , 18 .
that is , as the pro - inflammatory cytokines increase rapidly , 
 anti - inflammatory cytokines such as il-6 also increase accordingly to bring about balance in 
 cytokine secretion . in this study
, the level of il-6 in each group and in each stage did not appear to differ 
 significantly from each other .
the stagnant level of il-6 during the intensive exercise 
 might be regarded as indicating that glutamine supplementation could have prevented the 
 increase in inflammation induced by exercise ; however , it would be difficult to draw a clear 
 conclusion based on those insignificant results .
besides , it has been reported that il-6 is 
 discharged from the muscle to maintain glucose homeostasis and that the il-6 created in 
 skeletal muscle activates amp - kinase , which subsequently stimulates intramuscular glucose 
 uptake and fat oxidation19 . thus , the 
 increase in il-6 secretion might not occur due to supplementary effects on energy from 
 glutamine supplementation however , given the insignificant results obtained in the present 
 study , it would be difficult to insist that there were clear effects related to glutamine 
 supplementation .
it is known that il-8 causes inflammation by activating inflammatory cells and that it is a 
 chemokine produced by macrophages and other cell types such as epithelial cells .
it serves as a 
 chemical signal that attracts neutrophils at the site of inflammation , and therefore is also 
 known as neutrophil chemotactic factor .
il-15 , a sort of cytokine related to immune 
 function , is created in the mononuclear phagocyte , macrophage , and muscle to trigger the 
 creation of natural killer cells20 .
the results of the present study showed that there were no significantly differences in 
 il-8 among the 3 groups in the resting stage or at the end of exercise ; however , in the case 
 of il-15 , the ps and bs groups showed differences , and the gs group did not .
the results 
 regarding il-8 obtained in this study turned out to be different from those of another study 
 reporting that the concentration of the chemokine il-8 was increased18 , and this was probably due to the difference in the level 
 of exercise intensity and duration , which would have been insufficient to stimulate the il-8 
 reaction .
fischer reported that the blood chemokine concentrations would increase little or 
 remain stagnant unless a sufficient muscle mass is not mobilized and maintained at a certain 
 level of intensity sufficiently21 ; thus , 
 it seems that changing the blood chemokine concentrations requires performance of exercise 
 at a comparatively high - intensity for a long duration .
besides , differences in the blood 
 il-15 concentration were apparent in the ps and bs groups in the resting stage and at the 
 end of exercise except in the gs group .
this shows that il-15 has a more sensitive reaction 
 than il-8 to exercise , and it seems that the glutamine supplementation caused an effective 
 increase in the amount of saved glutamine . as the amount of glutamine application decreases , 
 the cell proliferation rate of lymphocytes decreases , and antioxidants , peptides , oxidative 
 stress , amino sugars related to cell resistance against and apoptotic processes , purines , 
 and synthesis of key molecules such as pyrimidines also decrease accordingly22 .
moreover , along with the decrease in the 
 saved amount of glutamine , neutrophils and macrophages , which are crucial to immune function 
 and the inflammatory response , and the protective activity related to apoptosis of 
 lymphocytes might also decrease23 .
so , 
 the il-15 concentrations observed in the ps and bs groups were increased as a compensational 
 effect corresponding to the decrease in the glutamine level , and in the gs group , the il-15 
 concentration was not increased because the immune function and inflammatory defense 
 reaction were not diminished .
compared with the group supplemented with the placebo , the groups supplemented with bcaa or 
 glutamine showed a lower level of blood phosphorous during the recovery stage after maximal 
 intensity exercise . regarding blood ck ,
the groups supplemented with glutamine alone 
 appeared to have a lower concentration than the other groups , which suggests positive 
 effects on reduction of fatigue factor stimulation .
differences in measurements of blood 
 il-6 and il-15 were found between the resting stage and the end of exercise in the ps group 
 and bs group , but not in the gs group .
thus , glutamine supplementation could be helpful for 
 enhancement of immune function and the defensive inflammatory reaction after exercise .
   [ purpose ] this study was conducted to understand the impacts of bcaa ( branched - chain 
 amino acid ) and glutamine supplementation on the degree of blood fatigue factor 
 stimulation and cytokines along with performance of exercise at the maximal intensity . 
 
 [ subjects ] five male juvenile elite rowing athletes participated in this study as the 
 subjects ; they took 3 tests and received placebo supplementation ( ps ) , bcaa 
 supplementation ( bs ) , and glutamine supplementation ( gs ) . 
 [ methods ] the exercise applied 
 in the tests was 2,000  m of rowing at the maximal intensity using an indoor rowing 
 machine , and blood samples were collected 3 times , while resting , at the end of exercise , 
 and after 30  min of recovery , to analyze the blood fatigue factors ( lactate , phosphorous , 
 ammonia , creatine kinase ( ck ) ) and blood cytokines ( il ( interleukin)-6 , 8 , 15 ) . [ results ] 
 the results of the analysis showed that the levels of blood phosphorous in the bs and gs 
 groups at the recovery stage were decreased significantly compared with at the end of 
 exercise , and the level of ck appeared lower in the gs group alone at recovery stage than 
 at the end of exercise . the level of blood il-15 in the ps and bs groups appeared higher 
 at the end of exercise compared with the resting stage . 
 [ conclusion ] it seemed that 
 glutamine supplementation had a positive effect on the decrease in fatigue factor 
 stimulation at the recovery stage after maximal intensity exercise compared with 
 supplementation with the placebo or bcaa . 
 besides , pre - exercise glutamine supplementation 
 seemed to help enhance immune function and the defensive inflammatory reaction . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION