Journal of Exercise Physiologyonline

84 Journl of Exercise Physiologyonline December 2012 Volume 15 Number 6 Editor-in-Chief Tommy Officil Boone, Reserch PhD, Journl MBA of Review the Americn Bord Society of Todd Exercise Astorino, Physiologists PhD Julien Bker, PhD Steve Brock, ISSN 1097-9751 PhD Lnce Dlleck, PhD Eric Goulet, PhD Robert Gotshll, PhD Alexnder Hutchison, PhD M. Knight-Mloney, PhD Len Krvitz, PhD Jmes Lskin, PhD Yit Aun Lim, PhD Lonnie Lowery, PhD Derek Mrks, PhD Cristine Mermier, PhD Robert Robergs, PhD Chntl Vell, PhD Dle Wgner, PhD Frnk Wytt, PhD Ben Zhou, PhD Officil Reserch Journl of the Americn Society of Exercise Physiologists ISSN 1097-9751 JEPonline Effects of Sodium Bicrbonte Ingestion during n Intermittent Exercise on Blood Lctte, Stroke Prmeters, nd Performnce of Swimmers Edurdo Zpterr Cmpos 1, Edurdo Bernrdo Sngli 1, José Geros Neto 1, Ronldo Bucken Gobbi 1, Ismel Forte Freits Junior 1, Mrcelo Ppoti 1,2 1 Lbortory of Physiology of Exercise - Stte University Pulist - Presidente Prudente/SP, 2 University of So Pulo, Ribeirão Preto/SP ABSTRACT Cmpos EZ, Sngli EB, Geros Neto J, Gobbi RB, Freits Junior IF, Ppoti M. Effects of Sodium Bicrbonte Ingestion during n Intermittent Exercise on Blood Lctte, Stroke Prmeters, nd Performnce of Swimmers. JEPonline 2012;15(6):84-92. The purpose of this study ws to investigte the effects of sodium bicrbonte (NHCO 3 ) ingestion in high intensity intermittent exercise on blood lctte ([L - ]), stroke prmeters, nd performnce of swimmers. Ten swimmers completed six mximl front crwl efforts of 100 m interspced by 6 min of rest in both situtions: NHCO 3 (SB) nd dextrose (plcebo). The SB (0.3 g kg -1 of body mss) or the plcebo ws ingested 60 min before the trining in geltin cpsules. After ech effort, the rting of perceived exertion (RPE) ws ssessed nd blood smple ws collected. Stroke length (SL), stroke rte (SR), nd stroke index (SI) were mesured. All prmeters were compred using twowy repeted mesures ANOVA, followed by Tukey post-hoc test. The significnce ws set t 5%. The [L - ] in the sixth effort fter SB (17.93 ± 3.8 mmol l -1 ) supplementtion ws significntly higher thn plcebo [L - ] (15.67 ± 3.29 mmol l -1 ) (P<0.05). No difference ws found between SB nd plcebo for the time 100 m -1 of ny of the six swims. Neither stroke prmeters (SL, SF, nd SI) nor RPE were significntly different in ll swim efforts. In conclusion, NHCO 3 did not improve performnce in swimming trining, but did enhnce the glycolytic source without ltertion of RPE. Key Words: Swimming, Sodium Bicrbonte Supplementtion, Rting of Perceived Exertion, Exercise

85 INTRODUCTION The success of intermittent trining is dependent on intensity nd effort recovery reltionship tht consists of increses both erobic nd nerobic components (5,10,23,30). When compred to continuous trining of the sme energy expenditure, intermittent exercise promotes n improvement in crbohydrte nd lctte metbolism (18). Elevted glycolytic metbolism increses the production of lctic cid nd the dissocition into hydrogen ions (H + ) nd lctte, simultneously decresing the ph of the blood (11,16,30). Among the effects of reduced ph (incresed H + ) re the inhibitions of clcium ions relesed from the srcoplsmic reticulum, of the interction of ctin nd myosin, nd of the ctivity of phosphofructokinse. All three effects led to decresed force production (20). The use of sodium bicrbonte (NHCO 3 ) is suggested to dely ftigue during mximl efforts with durtion between 1 to 10 min (2,14,20) by mitigting the decline of ph (6,12). Thus, despite some contrdictory findings (3,14,21,24,25,27,28) bout the ergogenic effects of NHCO 3, it hs been used to enhnce performnce in severl sports (6,18,22). Lindh et l. (14) found tht supplementtion of 300 mg kg -1 of NHCO 3 improved the performnce of 200 m in elite swimmers due to the increse in buffering cpcity. The benefits of NHCO 3 on high intensity intermittent exercise were recently demonstrted. Findings by Siegler nd Gledll-Siddll (21) suggest potentil use of NHCO 3 in trining sessions for swimmers who wnt to improve the qulity of their high-intensity trining. In swimming, the qulity of the trining sessions is extremely dependent on the stroke prmeters (21). If NHCO 3 promotes the mintennce or even llevites the deteriortion in stroke prmeters during the sessions of intermittent high-intensity trining, it would be resonble to conclude tht the swimmers would benefit from this nutritionl strtegy. However, to our knowledge, no study ssessed the effects of NHCO 3 on the chnges in the prmeters of swimming together with the performnce of the swimmers. Thus, the im of the present study ws to evlute the effect of supplementtion of NHCO 3 on the mechnicl prmeters of swimming, physiologicl responses, rting of perceived exertion, nd performnce of high-level swimmers. METHODS Subjects Ten swimmers (3 femle nd 7 mle) (men ± SD: ge 18.33 ± 3.33 yr), volunteered to prticipte in the present study. The subjects hd minimum of 2 yr in competitive swimming, trining volume of pproximtely 7000 m d -1 with frequency of 6 d wk -1. Personl best times were t 85% of the world record of the specific style. The subjects were informed bout experimentl procedures nd risks, nd signed n informed consent before their prticiption in the study. The experimentl protocol ws pproved by the Reserch Ethics Committee of the ssocited institution nd ws performed in ccordnce with ethicl stndrds. Procedures The tests were performed in 25 m outdoor pool with wter temperture of 24-25ºC. At the end of the specified preprtory period, the tests took plce in 3 dys with n intervl up to 7 dys. During the first dy, body composition ws estimted by Dul-Energy X-ry Absorptiometry (DEXA,Lunr DPX-NT; Generl Electric Helthcre, Little Chlfont, Buckinghmshire, with softwre version 4.7). During the 2nd nd 3rd dys, the swimmers performed, rndomly, six mximl efforts of 100 m fter ingestion of NHCO 3 (SB) or dextrose (plcebo). A double-blind protocol ws used. In order to keep the testing s close s possible to the prctice sessions, the trining lod for ech subject (i.e., thlete) ws kept s usul.

Supplementtion of Sodium Bicrbonte nd Plcebo The SB supplementtion involved dose of 0.3 mg kg -1 of body mss, while the plcebo ws the sme dose of dextrose. The supplements were consumed 60 min before the strt of efforts (13) with wter consumption d libitum. To reduce gstro intestinl discomfort the NHCO 3 ws ingested with individulized number of geltin cpsules (27). Mechnicl Stroke Prmeters nd Rting of Perceived Exertion (RPE) The subjects indicted their rting of perceived exertion (RPE) t the end of ech effort, using tble of 15 points (6-20) (4). Mechnicl stroke prmeters, the stroke frequency (SF), stroke length (SL), nd stroke index (SI) were determined. The SF ws determined by the rtio between the number of strokes (NS) nd time 100 m -1. The SL prmeter ws determined by dividing the NS for 100 m. The SI ws ssumed s the product between SL nd swimming speed (7). Blood Anlysis nd Lctte Accumultion Index (LAI) Resting blood smples were collected prior to the wrm-up of the subjects. After ech effort, 25 µl of blood were collected nd immeditely deposited in eppendorfs tubes contining nticogulnt solution of sodium fluoride (1%). Lter, the blood ws nlyzed using lctimeter YSI Yellow Spring (Sport Model -1500 ) to determine the lctte concentrtion ([L - ]). The subjects were verblly encourged throughout the tests to ensure the ttinment of mximl effort (8). The LAI ws clculted in ech sprint s the rtio of the [L - ] nd the time 100 m -1 (s) (LAI = [L - ]/(time 100 m -1 ). Sttisticl Anlyses The normlity nd homogeneity of the dt were confirmed with the Shpiro-Wilk's test nd Levene's test, respectively. The physiologicl vlues ([L - ] nd LAI), the mechnicl prmeters, nd the time 100 m -1 (T1 o, T2 o, T3 o, T4 o, T5 o, T6 o ) obtined in the plcebo nd SB conditions were compred by two-wy ANOVA test for repeted mesures, the post-hoc Tukey s test ws used to evlute the difference between the efforts nd the plcebo nd SB conditions. The significnce ws set t 5%. 86 RESULTS Significnt differences were found between the times in the six 100 m effort both in the plcebo nd the SB conditions, while between plcebo nd SB no significnt differences were found (Figure 1). Time (s. 100 meters) 70 69 68 67 66 65 64 63 62 61 Plcebo SB Figure 1 b b b bc bcd bc 60 1 st 2 nd 3 rd Efforts 4 th 5 th 6 th Figure 1. Performnce (s 100 m -1 ) Altertions During the 100 meters Efforts., time (s 100-1 ) during the plcebo condition;?, time (s 100 m -1 ) during SB., significntly difference of the 1st effort; b, significntly difference of the 2nd effort; c, significntly difference of the 3rd effort; d, significntly difference of the 4th effort.

The [L - ] in the 6º effort ws significnt higher in SB (17.93 ± 3.8 mmol l -1 ) compred with plcebo (15.67 ± 3.29 mmol ll -1 ). In both conditions the [L - ] in the first effort ws significntly lower thn in the subsequent five, nd the lst effort ws higher thn the 2º, 3º nd 4º sets (Figure 2). Figure 2 87 20 18 16 Plcebo SB bc bcd * Lctte (mmol. l -1 ) 14 12 10 b b bcd 8 6 1 st 2 nd 3 rd Efforts 4 th 5 th 6 th Figure 2. Lctte Concentrtion (mmol l -1 ) After Ech 100 meters Effort., [L - ] (mmol l -1 ) during the plcebo condition;?, [L - ] (mmol l -1 ) during SB., significntly difference of the 1st effort; b, significntly difference of the 2nd effort; c, significntly difference of the 3rd effort; d, significntly difference of the 4th effort. * P<0.05. No difference ws found in RPE between the plcebo nd SB. However, significnt differences were found between RPE in the sme condition (Figure 3). Figure 3 21 20 Plcebo SB bc b RPE (.u) 19 18 17 b b bc 16 15 1 st Efforts 2 nd 3 rd 4 th 5 th 6 th Figure 3. Rting Perceived Exertion (.u) of Ech 100 meters Effort., RPE (.u) during the plcebo condition;?, RPE (.u) during SB., significntly difference of the 1st effort; b, significntly difference of the 2nd effort; c, significntly difference of the 3rd effort

In Tble 1 re rrnged the stroke prmeters (SL, SF, nd SI) of the six trils in two conditions (plcebo nd SB). No significnt difference ws found between SB nd plcebo in the stroke prmeters. During the efforts, ltertions were founds in SL, SF, nd SI of plcebo nd SB (Tble 1). A significnt difference ws found between plcebo nd SB in LAI of the 6th sprint (0.23 ± 0.06 mm seg -1 vs. 0.27 ± 0.07 mm seg -1, respectively). No difference ws observed between plcebo nd SB in other efforts. 88 Tble 1. Stroke Prmeters (men ± SD) for SB nd Plcebo Condition t All the Six Effort. SF (Hz) SL (m) SI (.u) SB Plcebo SB Plcebo SB Plcebo 1st 1.19 ± 0.1 1.18 ±0.12 1.41 ± 0.16 1.42 ± 0.18 2.18 ± 0.42 2.26 ± 0.45 2nd 1.16 ± 0.1 1.15 ± 0.10 1.38 ± 0.15 1.40 ± 0.17 2.15 ± 0.41 2.19 ± 0.46 3rd 1.14 ± 0.1 1.12 ± 0.11 1.37 ± 0.14 1.40 ± 0.18 2.11 ± 0.40 2.17 ± 0.45 4th 1.12 ± 0.1 1.11 ± 0.10 b 1.35 ± 0.13 1.38 ± 0.18 2.08 ± 0.40 b 2.15 ± 0.45 5th 1.11 ± 0.1 bc 1.10 ± 0.10 b 1.33 ± 0.13 b 1.36 ± 0.16 bc 2.06 ± 0.38 b 2.12 ± 0.45 b 6th 1.07 ± 0.1 bc 1.09 ± 0.11 bc 1.31 ± 0.13 bc 1.35 ± 0.16 bc 2.03 ± 0.38 bc 2.09 ± 0.44 bcd Men 1.13 ± 0.1 1.13 ± 0.11 1.38 ± 0.14 1.39 ± 0.17 2.15 ± 0.40 2.17 ± 0.45 Abbrevitions: SF; stroke frequency, SL; stroke length, SI; stroke index, SB; sodium bicrbonte tril, Plcebo; plcebo tril., significntly different of the 1st effort; b, significntly different of the 2nd effort; c, significntly different of the 3rd effort; d, significntly different of the 4th effort. DISCUSSION The primry finding ws tht NHCO 3 supplementtion hd no ergogenic effect on the subjects performnce of 6 consecutive 100 m efforts with 6 min intervl. But, NHCO 3 supplementtion did result in n increse [L - ] in the lst effort without chnge in RPE. Although NHCO 3 promotes n ergogenic effect on efforts lsting 1 to 10 min (14,19), the present study showed no improvement in the performnce of ny 100 m effort in the SB condition. The decrese in performnce during the 6 efforts ws similr in plcebo nd SB conditions (Figure 1). These findings re in disgreement with Lindh nd collegues (14) reported single effort of 200 m performnce improvement in elite thletes. Despite the different methodology, the first 100 m effort of the present study ws not different between plcebo nd SB. It seems tht elite thletes re ble to swim fster. They lso seem to present greter nerobic cpcity tht llows for higher level of cidosis nd, therefore, benefit from NHCO 3 more thn non-elite thletes. Siegler nd Gledll-Siddll (21) reported on the effect of NHCO 3 in trined swimmers following eight sets of 25 m with 5-sec puse, nd found reduction in the totl time of the sets (plcebo: 163.2 ± 25.6 sec, SB: 159.4 ± 25.4 sec). Thus, the elimintion of turn component could hve influenced the subjects improvement in swimming speed. In the present study, no difference in plcebo nd SB ws found in ny time 100 m -1, nd, s discussed by Siegler nd Gledll-Siddll

(21) nd Lindh nd collegues (14), the technicl nd competitive level of the subjects my hve influenced their performnce nd, therefore, the turn my hve diluted the improvement in SB. In ddition, the intervl between the sets my hve influenced the response of the swimmers. Siegler nd Gledll-Siddll (21) used shorter recovery time (5 sec) nd found differences in performnce. Although the present study did not nlyze ph ltertions, the dose of NHCO 3 (0.3 mg kg -1 ) ws used in other studies (18,24,30) nd showed to be effective in chnging ph nd the concentrtion of bicrbonte ion. The [L - ] ws significntly higher t the end of the lst 100 m effort (plcebo: 15.67 ± 3.29 mmol l -1 nd SB: 17.93 ± 3.80 mmol l -1 ; P<0.05). The increse in [L - ] ws reported by severl studies (6,18,27). Some hypotheses my explin the higher vlues of [L - ] on SB. The first one is relted to the fct tht the elimintion of [L - ] is incresed when the extrcellulr ph increses, justifying the incresed [L - ] with the NHCO 3 supplementtion (12,15). The second reltes to the higher glycolytic ctivity nd nerobic energy production due to better internl environment, which would increse performnce. However s to this hypothesis, in the present study, it ws not confirmed since there ws no significnt difference between the time 100m -1 in plcebo nd SB. Notwithstnding, the protocol used in the present study consisted of sets of specific trining for improvement in the tolernce to cidosis, so SB, besides chieving the gol of trining, llowed for higher production of [L - ] without decrese in the performnce of the subject. The RPE ws used to estimte physicl stress during exercise. This pproch is due to the close reltionship between RPE nd physiologicl mrkers relted to intensity (such s hert rte nd blood lctte) (9,17). The present study found no significnt difference between the vlues of RPE in plcebo or SB, but [L - ] ws higher in the lst set of SB (17.93 ± 3.80 mmol l -1 vs. 15.67 ± 3.29 mmol l -1 ). Ymnk et l. (26) did not find ny difference in RPE when studying the legs, even with higher [L - ] in SB fter set of intense exercise, which is in greement with the present study. Numerous studies hve shown elevted [L - ] fter NHCO 3 supplementtion (6,18,27). So, it seems tht despite the no chnge in RPE, SB incresed the production cpcity nd the lctte tolernce. Therefore, the ergogenic effect my be beneficil in trining tht is imed t incresing tolernce nd/or [L - ] production. As to the effect of SB on mechnicl stroke prmeters of swimming, no differences were found. The SF nd SL did not chnge due to mintennce of the number of strokes in 100 m efforts. In the sme wy, such s no chnge in swimming speed (time 100 m -1 ) ws verified (given tht the SI ws similr between the conditions. According to Siegler nd Gledll-Siddll (21), performnce in swimming depends on mechnicl fctors such s the turn component (21) s well s the level of the thletes (elite, competitive, nd non-elite) nd protocol used (i.e., the time of stimulus nd the recovery time). The LAI in the lst sprint ws significntly higher with the ingestion of SB (0.23 ± 0.06 mm seg -1 vs. 0.27 ± 0.07 mm seg -1 ). The significnt increse of [L - ] in the lst sprint in the SB condition is due to fctors lredy mentioned, which influenced the higher LAI. According to Deminice et l. (8), LAI hs positive ssocition with swimming prmeters, confirming the reltionship between physiologicl nd mechnicl prmeters. Despite the ccumultion of lctic cid cuse gret discomfort, loss of efficiency nd coordintion of the swimmers (1), the present study did not observe chnges of prmeters with concomitnt increse in [L - ]. 89

90 CONCLUSIONS We conclude tht the NHCO 3 supplementtion does not improve performnce nd stroke prmeters fter session of high intensity intermittent trining, with men durtion of 65.2 sec nd 6-min intervl. However, the [L - ] tolernce increses without chnging the RPE nd swimming prmeters, being good ergogenic to increse lctte tolernce. While this ergogenic might be useful in trining sessions, it ppers tht it is not helpful in one single effort. This thinking my chnge with elite thletes where NHCO 3 my help to improve performnce due to better nerobic performnce nd technicl skills Address for correspondence: Cmpos EZ, Msc, Roberto Simonsen Street, 305 Univ Estdul Pulist, Presidente Prudente, São Pulo, Brzil,19060-900. Phone (18)3229-7713 Emil. zcmpos@yhoo.com.br REFERENCES 1. Alberty M, Sidney M, Hout-Mrchnd F, Hespel JM, Pelyo P. Intrcyclic velocity vritions nd rm coordintion during exhustive exercise in front crwl stroke. Int J Sports Med. 2005;26:471-475. 2. Berger NJA, McNughton LR, Ketley S, Wilkerson DP, Jones AM. Sodium bicrbonte ingestion lters the slow but not the fst phse of VO 2 kinetics. Med Sci Sports Exer. 2006;38(11):1909-1917. 3. Bishop D, Cludius B. Effects of induced metbolic lklosis on prolonged intermittent-sprint performnce. Med Sci Sports Exer. 2005;37(5):759-767. 4. Brink MS, Visscher C, Arends S, Zwerver J, Post WJ, Lemmink KA. Monitoring stress nd recovery: new insights for the prevention of injuries nd illnesses in elite youth soccer plyers. Br J Sports Med. 2010;44(11):809-815. 5. Burgomster KA, Howrth KR, Phillips SM, Rkobowchuk M, McDonld MJ, McGee SL, Gibl MJ. Similr metbolic dpttions during exercise fter low volume sprint intervl nd trditionl endurnce trining in humns. J Physiol. 2008;586(1):151-160. 6. Cmeron SL, McLy-Cooke RT, Brown RC, Gry AR, Firbirn KA. Incresed blood ph but not performnce with sodium bicrbonte supplementtion in elite rugby union plyers. Int J Sport Nutr Exerc Metb. 2010;20(4):307-321. 7. Costill DL, Kovleski J, Porter D, Kirwn J, Fielding R, King D. Energy expenditure during front crwl swimming: predicting success in middle-distnce events. Int J Sports Med. 1985;6(5):266-270. 8. Deminice R, Gbrr L, Rizzi A, Bldisser V. Série de treinmento intervldo de lt intensidde como índice de determinção d tolerânci à cidose n predição d performnce neróbi de ntção. Rev Brs Med. Esporte 2007;13(3):185-189.

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