There have been several recent qualitative review articles published on the topic, and Bsta-alanine we present a preliminary quantitative Energy-boosting shots of the literature through a meta-analysis.
A byffering search of the literature was employed to identify Beta-alnine studies suitable for inclusion in the Balanced diet for youth athletes strict bufferung criteria were also applied.
Fifteen published manuscripts were included in musclf analysis, which reported the results of 57 measures within 23 exercise tests, using 18 supplementation regimes and a total of participants [, β-alanine supplementation group BA Organic food options tips for anxiety management, placebo supplementation group Capwcity ].
The median effect of β-alanine supplementation is a 2. Erick P. de Oliveira, Guilherme Beta-alanine and muscle buffering capacity. Nicholas F. Bufferinng, Michael D.
Chloe Gao, Saurabh Gupta, … Bet-aalanine P. Anaerobic capacit is Buckwheat and digestion dominant energy capacigy during high-intensity exercise. Nonetheless, Carb cycling for endurance athletes interferes with several metabolic bufefring that Pomegranate farming techniques result in reduced force production and bugfering Spriet et al.
Physicochemical buffers in the muscle, of which carnosine is one, provide the first musclr of defence against bufferlng changes in pH. β-alanine is the rate Orange Fruit Facts precursor to the synthesis of carnosine within mucsle fibres Ng and Marshall ; Skaper et al.
Further support for the Coconut Oil for Pets role Beta-alanune carnosine in skeletal muscle comes from aand Beta-alanine and muscle buffering capacity concentrations found Pharmaceutical-grade ingredient innovation fast-twitch muscle fibres Harris et al.
In isolated muscle, the absence of carnosine as a buffering agent leads to buffeeing due to acidification, which does not bufering when carnosine is present in the surrounding medium Severin et al. Since muscle acidosis is likely to contribute to the onset of fatigue during high-intensity Sugar and inflammation, increasing the muscle carnosine concentration Hydration strategies for trail runners theoretically buffdring the intracellular buffering capacity, thereby potentially Sleep support supplements for athletes the onset of bbuffering.
Indeed, supplementation with β-alanine has been Beha-alanine to significantly elevate carnosine levels in capcity type I and type II human muscle fibres of the vastus lateralis Harris et al.
This ergogenic effect of β-alanine supplementation on high-intensity exercise performance in humans has led to Beta-alnaine expansion Beta-alanind the commercial market anx β-alanine in recent years. There has also been a concomitant increase in interest in capacoty research area, so much so that, since the first muscel on the topic by Bufvering et al.
While these reviews are muscls a useful bufferihg to synthesise the available literature, such literature can also be analysed collectively in a quantitative way through meta-analysis.
As such, the primary aim ane this meta-analysis was to analyse the capcaity available on the ergogenic effect of β-alanine supplementation on exercise.
The secondary aim was to investigate the outcome of the different exercise protocols employed, i. This meta-analysis buffsring not attempt to conduct a traditional qualitative review concurrently with the quantitative data presented here, and Beta-alanine and muscle buffering capacity readers are directed musfle the capaxity review articles Beeta-alanine above for details of the studies included in this meta-analysis.
The published literature caapcity searched using cpacity databases of PUBMED, SPORTDiscus and GoogleScholar in Buffering Hand searches of journal articles and of the an lists from relevant publications were also buffsring to ensure, as far as practically possible, that all appropriate ajd were considered for inclusion.
Once all relevant articles ajd been located, three bufferng individually considered Orange Fruit Facts article for its appropriateness for inclusion based BBeta-alanine the pre-determined inclusion criteria discussed juscle. Where conflict in capaxity arose the majority ruled on the inclusion or exclusion of the article.
Several other desirable characteristics of studies were also discussed, such as the homogeneity of the participant Brta-alanine and the availability of information on the reliability of the exercise tests and measures employed, however, the bufferkng criteria remained as abd were.
This analysis was amd to manuscripts Bega-alanine human participants in Orange Fruit Facts controlled, double blinded trials, published in English language peer reviewed journals, and musclf had a β-alanine only supplementation group BA and a placebo group Pla.
Summary details of the studies included in the meta-analysis are buffeirng in Table 1. Due to these inclusion criteria, several studies qnd excluded from the analysis, for bufferlng multitude of reasons.
These muscel those with amd β-alanine only experimental group Hoffman et al. Capavity and post-supplementation mean Beta-aalnine standard deviations SD were obtained from the original data included in Beta-alanine and muscle buffering capacity published papers.
Where this information was not bfufering Sale et al. Unfortunately, further information was not received bufdering Derave and his co-workers in relation to their data on isokinetic peak force production and, as such, this Beta-alaninr is capackty included in the meta-analysis.
Musce effectiveness of the supplementation for BA and Pla groups was quantified by calculating Beta-wlanine effect size, which capacityy the difference between the pre- and post-supplementation measures, divided by the pooled SD of the two occasions. Therefore, effect size represents a common measure of treatment effectiveness, which allows the findings of individual studies to be analysed together.
Where a smaller number represents a better result such as running performancethe subtraction is reversed and thus a positive effect size still represents a positive treatment effect.
Each effect size was then corrected to adjust for any positive bias due to small sample size Thomas and French The studies of Hill et al. Exercise measures were analysed as one complete group for the overall effect of β-alanine supplementation compared to a placebo.
Due to the mechanisms by which β-alanine is proposed to have an ergogenic effect on exercise, the data were then sub-divided.
Where possible, data were separated into those generated by exercise capacity and exercise performance tests.
Although exercise performance tests are deemed to have a greater level of ecological validity, they rely upon intrinsic pacing strategies which may not elicit optimal performance Hinckson and Hopkins If there is no fixed pacing strategy, as may be the case in sub-elite athletes, then the effects of an intervention might be masked by large variance; if there is a fixed pacing strategy, as may be the case in elite or experienced athletes, it may not allow the effects of an intervention to be shown.
Therefore, exercise capacity and exercise performance data were analysed separately. Measures were also sub-divided by exercise duration, given that β-alanine supplementation increases carnosine concentrations in skeletal muscle and acts indirectly to increase muscle buffering capacity.
Finally, the dose of β-alanine administered above or below the average daily and total dose, as determined by mean and median was also investigated to determine if there was a direct link between the dose and the effect of β-alanine.
Information regarding which tests were included in each grouping is available in Table 2. With the data divided as BA and Pla groups, and the number of effect sizes in each group dictated by the variable being investigated, the data were analysed for skewness, kurtosis and normality of distribution.
Fifteen published investigations met the inclusion criteria see Table 1 for study details. Several studies employed multiple exercise tests and multiple measures within those tests, therefore 57 effect sizes were calculated for inclusion in the analysis.
A total of participants were included, subdividing into participants in the BA group and participants in the Pla group; the average group size was 12 participants, with a range of 7—20 participants.
Of the participants, Of the 15 studies included in the meta-analysis, 8 acknowledge the donation of the supplement used from a commercial company and 3 state the brand of supplement used, but 4 studies make no reference as to the source of the β-alanine administered Stout et al.
Furthermore, five manuscripts acknowledge an element of financial support for their study from a commercial company Hill et al. The effect size of the Pla group was 0. Further data analysis indicates that supplementation with a total of g of β-alanine the median dose across all studies would result in a median improvement of 2.
Twelve exercise performance measures were employed in six studies see Table 2 for details. When combined, tests such as rowing performance Baguet et al.
The effect size of Pla and BA groups when subdivided by type of exercise test or measure. Light grey represents Pla groups and dark grey represents BA groups. Thirteen of the fifteen studies included in this meta-analysis employed a total of 27 exercise capacity measures to investigate the effects of β-alanine supplementation.
BA groups had an effect size of 0. For the 9 measures lasting 60— s there was a significant difference between the effect size of the BA and Pla groups [0. However, once exercise duration increased over s the beneficial effects of β-alanine supplementation from the 34 measures become less pronounced, although still significant [BA 0.
Figure 2 demonstrates this pattern. The effect size of Pla and BA groups when subdivided by exercise duration. A large variety of supplementation protocols were employed, meaning that the total amount of β-alanine ingested by each participant varied from The difference in the median effect size between the BA and Pla groups for each study is plotted in relation to the total dose of β-alanine supplemented in Fig.
Through regression analysis, the data of Stout et al. The difference in the median effect size of the BA and Pla groups of each study in relation to the total dose of β-alanine supplemented.
To our knowledge, this is the first meta-analysis to be published on this topic and it shows that there is a significant effect of β-alanine supplementation on all exercise measures when taken as a single group. Analysis indicates that supplementation with a total of g of β-alanine the median dose across all studies would result in a median improvement of 2.
Assuming a linear relationship between running speed and percentage effect, if this improvement was extrapolated and applied to a sporting event lasting around 4 min, such as a 1, m run, performance time would be improved by ~6 s.
It should be noted that this calculation is based upon the median effect across several studies, and the vast majority of participants in the studies of this meta-analysis are recreationally active individuals rather than elite athletes.
Of these, only one yard shuttle run; Kern and Robinson falls within the time frame in which β-alanine supplementation is most efficacious 60— s. These studies have shown that, with Therefore, given the potential demonstrated for significant improvements in exercise lasting 60— s, this meta-analysis highlights the need for more studies investigating the effects of β-alanine supplementation on exercise performance of this duration.
However, to date, the available data suggests that β-alanine supplementation has no benefit on measures of exercise performance rather than exercise capacity. This result is perhaps unsurprising as only 2 of the 12 performance measures included in the meta-analysis have shown a significant difference between the BA and Pla groups mean power output and peak power output in a 30 s cycle sprint, after min of previous cycling; Van Thienen et al.
However, this is unlikely to be the true explanation for the results seen here as 3 of the 6 studies conducted full familiarisation trials with the participants prior to testing Kendrick et al. Although it can be argued that performance tests are more ecologically valid Coyle et al.
Exercise capacity tests do not require this skill and are often of more use in exercise physiology research, where mechanistic investigations are often the focus rather than the artificial recreation of a sporting setting. Furthermore, exercise capacity tests are, by their very nature, maximal and will, therefore maximally stress the homeostasis of the internal environment.
Exercise performance tests may not be maximal due to the use of pacing strategies, be these consistent strategies which mask the effect of an intervention, or inconsistent strategies which increase variability. It is possible that differences in the efficacy of β-alanine supplementation between performance and capacity tests and measures exist due to these factors.
Currently it would seem likely that the main ergogenic mechanism by which β-alanine acts is through an elevation in carnosine synthesis within the muscle Harris et al.
Readers are directed to the review articles of Sale et al. The data in this meta-analysis clearly shows that exercise of a duration less than 60 s is not improved by β-alanine supplementation, while exercise of 60— s clearly is improved, and exercise over s is also improved, although to a lesser extent.
However, it should be noted that, despite previous research suggesting that a reduced muscle pH did not affect performance of a single bout of 30 s maximal cycling Bogdanis et al. Therefore, it is likely that the relationship shown by Suzuki et al. It is possible that, the area occupied by type II muscle fibres was more important to 30 s maximal sprint cycling than pH regulation directly.
This meta-analysis supports the findings of Bogdanis et al. Therefore, other pathways related to β-alanine supplementation and the role of carnosine in the muscle, such as an effect of β-alanine on delaying the fatigue induced increase in ventilation rate Stout et al.
Stellingwerff in press recently published findings which demonstrate that as the dose of β-alanine supplemented increases, the duration of supplementation required to elicit changes in the muscle carnosine content is reduced. There is currently no known threshold to the storage of carnosine in muscle and therefore it would seem logical that the more β-alanine that is supplemented, be that at a lower dose over a longer duration or at a higher dose over a shorter duration, the more carnosine can be synthesised and stored in the muscle.
This could lead to a greater muscle buffering capacity during high-intensity exercise and therefore an improvement in exercise outcomes. Indeed, this theory is partially supported by the data of Hill et al.
: Beta-alanine and muscle buffering capacity| Top bar navigation | Peart DJ, Siegler JC, Vince RV. J Appl Physiol —13 PubMed CAS Google Scholar Stellingwerff T, Anwander H, Egger A, Buehler T, Kreis R, Decombaz J, Boesch C Effect of two β-alanine dosing protocols on muscle carnosine synthesis and washout. Several studies employed multiple exercise tests and multiple measures within those tests, therefore 57 effect sizes were calculated for inclusion in the analysis. Effects of induced alkalosis on simulated match performance in elite female water polo players. It may be speculated that muscle carnosine content was elevated in the majority of the subjects in the BA group at the time of the ramp incremental test but not at the time of the 3-min all-out tests. Article PubMed Central PubMed CAS Google Scholar Ormsbee MJ, Thomas DD, Mandler WK, Ward EG, Kinsey AW, Panton LB, et al. Although evidence thus far is contradictory, there is currently a paucity of research on the co-supplementation of intracellular and extracellular buffering agents on exercise. |
| Beta-Alanine: Impacts On Muscle | Contact us Submission enquiries: Access here and click Contact Us General enquiries: info biomedcentral. On the third of training, the volunteers ran a long distance 12 km. Giandolini, M. Skeletal muscle and physical function are critical throughout the aging process. Several strategies have been adopted in order to minimise the discomfort associated with acute sodium bicarbonate supplementation, including multiday ingestion [ 94 ], chronic administration [ 95 ] and split-dose protocols [ 54 , 96 ]. |
| Introduction | Smith AE, Moon JR, Kendall KL, Graef JL, Lockwood CM, Walter AA, Beck TW, Cramer JT, Stout JR b The effect of β-alanine supplementation and high-intensity interval training on neuromuscular fatigue and muscle function. Stellingwerff T, Anwander H, Egger A, Buehler T, Kreis R, Decombaz J, Boesch C Effect of two β-alanine dosing protocols on muscle carnosine synthesis and washout. Amino Acids In Press. PubMed Google Scholar. Stout JR, Graves BS, Smith AE, Hartman MJ, Cramer JT, Beck TW, Harris RC The effect of beta-alanine supplementation on neuromuscular fatigue in elderly 55—92 years : a double-blind randomized study. Suzuki Y, Ito O, Mukai N, Takahashi H, Takamatsu K High; levels of skeletal muscle carnosine contributes to the latter half of exercise performance during maximal cycle ergometer sprinting. Jpn J Physiol — Sweeney KM, Wright GA, Brice AG, Doberstein ST The effects of β-alanine supplementation on power performance during repeated sprint activity. Thomas L Retrospective power analysis. Conserv Biol — Thomas JR, French KE The use of meta-analysis in exercise and sport: A tutorial. Res Q Exerc Sport — Trivedi B, Daniforth WH Effect of pH on the kinetics of frog muscle phosphofructokinase. J Biol Chem — Van Thienen R, Van Proeyen K, Vanden Eynde B, Puype J, Lefere T, Hespel P β-alanine improves sprint performance in endurance cycling. Walter AA, Smith AE, Kendall KL, Stout JR, Cramer JT Six weeks of high-intensity interval training with and without β-alanine supplementation for improving cardiovascular fitness in women. Watson P, Shirreffs SM, Maughan RJ The effect of acute branched chain amino acid supplementation on prolonged exercise capacity in a warm environment. Download references. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author s and source are credited. Biomedical, Life and Health Sciences Research Centre, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK. Hobson, B. Saunders, G. You can also search for this author in PubMed Google Scholar. Correspondence to C. Reprints and permissions. Hobson, R. et al. Effects of β-alanine supplementation on exercise performance: a meta-analysis. Amino Acids 43 , 25—37 Download citation. Received : 21 October Accepted : 09 December Published : 24 January Issue Date : July Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Download PDF. Safety of beta-alanine supplementation in humans: a narrative review Article 21 February The Effect of Dietary Nitrate Supplementation on Endurance Exercise Performance in Healthy Adults: A Systematic Review and Meta-Analysis Article 06 September The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis Article Open access 09 July Use our pre-submission checklist Avoid common mistakes on your manuscript. Introduction Anaerobic glycolysis is the dominant energy source during high-intensity exercise. Methods Literature review and study selection The published literature was searched using the databases of PUBMED, SPORTDiscus and GoogleScholar in July Table 1 A summary of the studies included in the meta-analysis Full size table. Table 2 A summary of the studies and measures included in the sub-sections of the meta-analysis Full size table. Results Studies Fifteen published investigations met the inclusion criteria see Table 1 for study details. Overall The effect size of the Pla group was 0. Exercise performance and capacity Twelve exercise performance measures were employed in six studies see Table 2 for details. Full size image. Discussion To our knowledge, this is the first meta-analysis to be published on this topic and it shows that there is a significant effect of β-alanine supplementation on all exercise measures when taken as a single group. Exercise intensity and duration Currently it would seem likely that the main ergogenic mechanism by which β-alanine acts is through an elevation in carnosine synthesis within the muscle Harris et al. β-alanine dosage Stellingwerff in press recently published findings which demonstrate that as the dose of β-alanine supplemented increases, the duration of supplementation required to elicit changes in the muscle carnosine content is reduced. Limitations of meta-analysis as a research technique During a meta-analysis, studies with critical flaws in the methodology can be omitted from the analysis at the outset. Conclusion and recommendations The median overall effect of β-alanine supplementation is a 2. No Time to Lift? Designing Time-Efficient Training Programs for Strength and Hypertrophy: A Narrative Review Article Open access 14 June Reference values for estimated VO2max by two submaximal cycle tests: the Åstrand-test and the Ekblom-Bak test Article Open access 22 January References Artioli GG, Gualano B, Smith A, Stout J, Lancha AH Role of β-alanine supplementation on muscle carnosine and exercise performance. Med Sci Sports Exerc — PubMed CAS Google Scholar Baguet A, Reyngoudt H, Pottier A, Everaert I, Callens S, Achten E, Derave W Carnosine loading and washout in human skeletal muscles. 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J Appl Physiol —13 PubMed CAS Google Scholar Stellingwerff T, Anwander H, Egger A, Buehler T, Kreis R, Decombaz J, Boesch C Effect of two β-alanine dosing protocols on muscle carnosine synthesis and washout. Amino Acids — Article PubMed CAS Google Scholar Stout JR, Graves BS, Smith AE, Hartman MJ, Cramer JT, Beck TW, Harris RC The effect of beta-alanine supplementation on neuromuscular fatigue in elderly 55—92 years : a double-blind randomized study. J Int Soc Sports Nutr Article PubMed Google Scholar Suzuki Y, Ito O, Mukai N, Takahashi H, Takamatsu K High; levels of skeletal muscle carnosine contributes to the latter half of exercise performance during maximal cycle ergometer sprinting. Jpn J Physiol — Article PubMed CAS Google Scholar Sweeney KM, Wright GA, Brice AG, Doberstein ST The effects of β-alanine supplementation on power performance during repeated sprint activity. J Strength Cond Res —87 Article PubMed Google Scholar Thomas L Retrospective power analysis. Conserv Biol — Article Google Scholar Thomas JR, French KE The use of meta-analysis in exercise and sport: A tutorial. Res Q Exerc Sport — Google Scholar Trivedi B, Daniforth WH Effect of pH on the kinetics of frog muscle phosphofructokinase. J Biol Chem — PubMed CAS Google Scholar Van Thienen R, Van Proeyen K, Vanden Eynde B, Puype J, Lefere T, Hespel P β-alanine improves sprint performance in endurance cycling. Med Sci Sports Exerc — Article PubMed Google Scholar Walter AA, Smith AE, Kendall KL, Stout JR, Cramer JT Six weeks of high-intensity interval training with and without β-alanine supplementation for improving cardiovascular fitness in women. J Strength Cond Res — Article PubMed Google Scholar Watson P, Shirreffs SM, Maughan RJ The effect of acute branched chain amino acid supplementation on prolonged exercise capacity in a warm environment. Amino Acids — Article PubMed CAS Google Scholar Download references. Conflict of interest The authors have no conflict of interest to declare. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author s and source are credited. Author information Authors and Affiliations Biomedical, Life and Health Sciences Research Centre, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham, NG11 8NS, UK R. Sale Junipa Ltd, Newmarket, Suffolk, UK R. Harris Authors R. Hobson View author publications. View author publications. Upon arrival, subjects performed a 5 min standardised warm-up, consisting of light jogging and running, followed by 5 min of self-selected stretching. The YoYo IR2 consists of repeated 40 m 2 x 20 m runs between markers set 20 m apart, at progressively increasing speeds dictated by an audio signal [ 11 ]. Subjects perform 10 s of active recovery between each running bout, consisting of a 10 m 2 x 5 m walk. The test was ended if the player failed to reach the finish line within the given time frame on two consecutive occasions or if the player felt unable to continue volitional exhaustion. The total number of levels was recorded and used to determine total distance covered m during the test. All data were analysed using Statistica 9 Statsoft, USA and are presented as mean ± 1SD. A two factor ANOVA Group x Trial was used to determine any differences in YoYo performance. Distance covered during the YoYo IR2 for both supplementation groups pre white bars and post black bars supplementation. Individual response to supplementation in the placebo and β-alanine groups pre YoYo 1 and post YoYo 2 supplementation. Players supplemented from early to mid-season are indicated by a solid line and players supplemented from mid- to the end of the season are indicated by a dotted line. In the group of players supplemented from early to mid-season, 2 out of 5 in PLA and 6 out of 6 in BA group improved YoYo IR2 performance. Of the remaining players supplemented from mid until the end of season, no one in PLA showed an improvement while 2 out of 3 in BA improved their distance covered. There was a clear effect of 12 weeks of β-alanine supplementation on the distance covered during the YoYo IR2 test. This is in contrast to previous research that has shown no effect of β-alanine on repeated sprint exercise [ 7 — 9 ], although these studies used exercise protocols consisting of performance tests incorporating periods of high-intensity and sprint activity of less than 60 s in duration, which are suggested to be unaffected by β-alanine supplementation [ 10 ]. Furthermore, distance covered during the YoYo IR2 has been associated with high-intensity running performed during competitive games play [ 12 , 13 ]. Therefore, the results of the present investigation suggest that β-alanine supplementation is effective at improving team sport specific exercise capacity. Although muscle carnosine concentrations were not directly determined in this study, Stellingwerff et al. Therefore, it can by hypothesised that 12 weeks of β-alanine supplementation at 3. As such, since one of the undisputed roles of muscle carnosine is in muscle buffering, the most likely explanation for the improvement in YoYo IR2 performance is due to an increase in intracellular buffering capacity, resulting in an attenuation of the reduction in intracellular pH during high-intensity exercise. Furthermore, all 8 of the players who improved with β-alanine did so above this expected CV, while the placebo group showed more variation with 3 players exceeding the CV 1 improved and 2 decreased their performance , which suggests that performance improvements in the β-alanine group can be attributed to the nutritional intervention employed in the current investigation. Since all players were involved in an identical training structure throughout the supplementation period, the further increases in these subjects could be attributed to an increased ability to train due to increased muscle buffering capacity [ 7 ], providing an additive effect over supplementation alone. Although mid-season scores were not different from the start of the season for First Division Scandinavian footballers, YoYo IR2 performance was decreased at the end of the season compared to the start of the season in another group of First and Second division players [ 13 ]. Furthermore, only 4 out of 15 players improved their YoYo IR2 performance during the season, while a further 9 showed a performance decrement [ 13 ]. In the present investigation, performance for players in the placebo group supplemented from early to mid-season followed a similar pattern to this, and all 3 supplemented from the middle until the end of the season showed a decline in performance. In contrast, all players supplemented with β-alanine from early- to mid-season improved their YoYo scores, while 2 of the 3 supplemented from mid-season until the end of the season showed a performance improvement, with the remaining player unchanged. These data provide evidence to suggest that β-alanine supplementation can not only halt the decline in fitness levels shown during a competitive season[ 13 ], but may even improve them above typical levels. The ingestion of 3. Improvements can be attributed to an increase in muscle buffering capacity due to increased muscle carnosine concentration, attenuating the decline in intramuscular pH during repeated high-intensity exercise bouts. Harris RC, Tallon M, Dunnett M, Boobis LH, Coakley J, Kim HJ, Fallowfield JL, Hill CA, Sale C, Wise JA: The absorption of orally supplied β-alanine and its effect on muscle carnosine synthesis in human vastus lateralis. Amino Acids. Article CAS PubMed Google Scholar. Bate-Smith EC: The buffering of muscle in rigour: protein, phosphate and carnosine. J Physiol. Article Google Scholar. Hill CA, Harris RC, Kim HJ, Harris BD, Sale C, Boobis LH, Kim CK, Wise JA: Influence of β-alanine supplementation on skeletal muscle carnosine concentrations and high intensity cycling capacity. Sale C, Saunders B, Hudson S, Wise JA, Harris RC, Sunderland CD: Effect of beta-alanine plus sodium bicarbonate on high-intensity cycling capacity. Med Sci Sport Exerc. CAS Google Scholar. Bishop D, Edge J, Goodman C: Muscle buffer capacity and aerobic fitness are associated with repeated-sprint ability in women. Eur J Appl Physiol. Article PubMed Google Scholar. Rampinini E, Sassi A, Morelli A, Mazzoni S, Fanchini M, Coutts AJ: Repeated-sprint ability in professional and amateur soccer players. Appl Physiol Nutr Metab. Hoffman JR, Ratamess NA, Faigenbaum AD, Ross R, Kang J, Stout JR, Wise JA: Short duration β-alanine supplementation increases training volume and reduces subjective feelings of fatigue in college football players. Nutr Res. Sweeney KM, Wright GA, Brice AG, Doberstein ST: The effects of β-alanine supplementation on power performance during repeated sprint activity. J Strength Cond Res. Saunders B, Sale C, Harris RC, Sunderland C: Effect of beta-alanine supplementation on repeated sprint performance during the Loughborough Intermittent Shuttle Test. Hobson RM, Saunders B, Ball G, Harris RC, Sale C: Effects of β-alanine supplementation on exercise performance: a review by meta-analysis. Article PubMed Central CAS PubMed Google Scholar. Bangsbo JL: Fitness training in football — A scientific approach. Google Scholar. Bangsbo J, Iaia MF, Krustrup P: The Yo-Yo Intermittent Recovery Test: A Useful Tool for Evaluation of Physical Performance in Intermittent Sports. Sports Med. The placebo PL; white and β-alanine BA; gray group mean and individual T lim during incremental INC KEE A,B and intermittent INT KEE C,D knee-extension exercise pre- circles and post- triangles supplementation. We employed a comprehensive exercise testing regimen, which included whole-body and single-legged exercise modalities and the use of 1 H- and 31 P-magnetic resonance spectroscopy to determine muscle carnosine content and muscle metabolic changes during exercise, respectively, to investigate the influence of BA supplementation on exercise performance. The principal findings of this study were that BA supplementation did not significantly increase muscle carnosine content or alter intramuscular pH or performance during incremental or intermittent knee-extension exercise, or alter the power-duration relationship during all-out cycling. Although there was great inter-individual variability in muscle carnosine responses to BA supplementation, no relationships were observed between muscle carnosine content and blood pH or exercise performance. The findings of the current study indicate that muscle carnosine content was not increased following 4 and 6 weeks of BA ingestion 6. This is in contrast to previous studies that have assessed muscle carnosine content using 1 H-MRS and have shown that BA supplementation results in increased carnosine content in muscles of the calf Baguet et al. Whilst these studies employed a variety of different supplementation strategies, and although baseline muscle carnosine content and loading rates appear to be muscle specific Baguet et al. In the present study, subjects had ingested a total of g BA after 4 weeks and g BA after 6 weeks. This finding is similar to Hill et al. Whilst a greater baseline carnosine content has been observed in human type II muscle fibers Suzuki et al. Therefore, individual differences in muscle fiber type composition are unlikely to explain inter-individual variation in muscle carnosine response to BA supplementation. Given that the subjects in the current study were matched at baseline, were not trained in any particular sport, and that there was no association between muscle carnosine increase and parameters of fitness i. It is possible that reduced L-histidine bioavailability at baseline and as a consequence of BA supplementation may, in part, explain differences in muscle carnosine responses between subjects in the current study and in previous research Harris et al. A novel finding of our study is that 4—6 weeks of BA supplementation may not always result in a measurable increase in muscle carnosine content cf. Hill et al. The factors regulating muscle carnosine content require further research. The ergogenic effect of BA supplementation has been primarily attributed to its role in the synthesis of muscle carnosine, a potent intramuscular pH buffer Bate-Smith, However, to our knowledge there has only been one study that has previously assessed muscle buffering capacity in humans following BA supplementation and, despite observing an increase in muscle carnosine, found no improvements in muscle buffering capacity Gross et al. In the current study, we used 31 P-MRS to assess muscle pH during single-legged knee-extension exercise. It was shown that BA supplementation did not result in changes in muscle pH at rest or during INC KEE or INT KEE and no performance improvement was observed. In addition to INT KEE, we used a repeated 3-min all-out cycling test to determine whether BA supplementation might improve recovery from intense whole-body exercise. In agreement with Saunders et al. This observation is consistent with there being no significant change in muscle carnosine content and no change in muscle pH or performance during INT KEE following BA supplementation. There was a small but possibly meaningful change in blood pH and performance during the ramp incremental cycling test following BA supplementation, despite no significant change in muscle carnosine content. The increased blood pH and ramp test performance are in contrast with previous studies that have shown no significant improvements in incremental test performance following BA supplementation Zoeller et al. The 3-min all-out test has been shown to be sensitive to detect changes in the power-duration relationship following training Vanhatalo et al. Therefore, dietary interventions that may transiently enhance muscle present study; Smith-Ryan et al. The effects of BA supplementation on high-intensity exercise performance are equivocal meta-analysis see Hobson et al. The discrepancy between findings does not appear consistently linked to differences in supplementation regimes or exercise test protocols. Ducker et al. The repeated performance of short sprint-intervals Sweeney et al. Although interpretation of the studies reporting no significant improvements following BA supplementation is limited due to the omission of a carnosine assessment Sweeney et al. It was not possible to assess muscle carnosine content on every laboratory visit due to the large number of tests. It is possible that a temporal lag of 3—4 days between some performance test visits and muscle carnosine scans influenced the accuracy of correlations between muscle carnosine and exercise performance indices. Previous research has shown, however, that muscle carnosine content is relative stable and has a slow wash-out rate following BA supplementation Stellingwerff et al. There was no significant difference in muscle carnosine between 4 and 6 weeks of BA supplementation in the present study, although some individual variability was evident Figure 1. It may be speculated that muscle carnosine content was elevated in the majority of the subjects in the BA group at the time of the ramp incremental test but not at the time of the 3-min all-out tests. This seems unlikely, however, and the randomization of exercise tests would have minimized any consistent order effect. These differences might have contributed to the small performance benefit observed in the ramp test but not the all-out sprint test. We assessed muscle carnosine in a 1. It should be noted, that all previous studies using 1 H-MRS to assess muscle carnosine content have used a 3. We can therefore be confident that: 1 the technique we used would have been sufficiently sensitive to detect the changes in muscle carnosine that have been reported previously Harris et al. In keeping with the lack of change observed in muscle carnosine content and thus buffering capacity, we found no differences in muscle pH during INC and INT KEE. Collectively, these findings strongly suggest that the supplementation regime did not successfully increase muscle carnosine content and muscle buffering capacity. Given that adherence to the supplementation regime was confirmed by each subject, it should also be considered that the supplement did not contain the expected dosage of BA. The possible absence of active ingredients in some commercially-available dietary supplements has been noted as a concern previously Maughan, However, given that the supplementation product used in this study had been tested to ensure that it contains the identity and quantity of ingredients indicated on the label NSF Certified for Sport , supplement contamination, and decreased presence or omission of the active ingredient seems unlikely. Why we did not observe a significant increase in muscle carnosine and thus muscle buffering capacity having used a certified supplement, followed an adequate BA loading strategy, and utilized a sufficiently sensitive method for carnosine detection, is unclear. A variety of high-intensity exercise tests comprising different work-rate forcing functions and exercise modalities were used to assess possible ergogenic effects of BA supplementation. Under the conditions of the present study, BA supplementation had a variable and non-significant effect on muscle carnosine content and no influence on intramuscular pH during high-intensity incremental or intermittent knee-extension exercise. The small increase in blood pH during ramp incremental cycle exercise following BA supplementation was associated with a small but significantly greater increase in performance relative to the PL group but this was not sufficient to alter the power-duration relationship. Our findings indicate that BA supplementation may not always increase muscle carnosine content, and clearly, in such circumstances, no effect on exercise performance would be expected. This study was carried out in accordance with the recommendations of University of Exeter Research Ethics Committee with written informed consent from all subjects. All subjects gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by the University of Exeter Research Ethics Committee. MB, AJ, and AV were involved in conceptual design, data collection, interpretation of results, and manuscript preparation; PM, JF, and SB were involved in data collection, interpretation of results, and manuscript preparation. MB, AJ, AV, PM, JF, and SB approved the final version of the manuscript and agreed to be accountable for all aspects of the work. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The BA supplements for this study were provided gratis by a distributor who wishes to remain anonymous. Jonathan Fulford's salary was supported via an NIHR grant. The authors thank Dr. David Bailey and Dr. Trent Stellingwerff for insightful discussions. Baguet, A. Important role of muscle carnosine in rowing performance. doi: PubMed Abstract CrossRef Full Text Google Scholar. 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The effect of β-alanine and NaHCO 3 co-ingestion on buffering capacity and exercise performance with high-intensity exercise in healthy males. Debold, E. Effect of low pH on single skeletal muscle myosin mechanics and kinetics. Cell Physiol. del Favero, S. Amino Acids 43, 49— Ducker, K. Effect of beta alanine and sodium bicarbonate supplementation on repeated-sprint performance. Strength Cond. Dunnet, M. Influence of oral β-alanine and L-histidine supplementation on the carnosine content of the gluteus medius. Equine Vet. Fitts, R. Cellular mechanisms of muscle fatigue. Gevers, W. The effect of pH on glycolysis in vitro. PubMed Abstract Google Scholar. Gross, M. Effects of beta-alanine supplementation and interval training on physiological determinants of severe exercise performance. Harris, R. The time course of phosphorylcreatine resynthesis during recovery of the quadriceps muscle in man. Pflugers Arch. The absorption of orally supplied b-alanine and its effect on muscle carnosine. 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