Método de determinação direto e indireto do máximo estado estável de lactato em pista de atletismo

1 UNIVERSIDADE CATÓLICA DE BRASÍLIA-UCB

PROGRAMA E PÓS-GRADUAÇÃO STRICTO SENSU EM EDUCAÇÃO FÍSICA

MÉTODOS DE DETERMINAÇÃO DIRETO E INDIRETO DO MÁXIMO ESTADO ESTÁVEL DE LACTATO EM PISTA DE ATLETISMO

Rafael da Costa Sotero

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Rafael da Costa Sotero

MÉTODOS DE DETERMINAÇÃO DIRETO E INDIRETO DO MÁXIMO ESTADO ESTÁVEL DE LACTATO EM PISTA DE ATLETISMO

Dissertação apresentada ao Programa de Pós-Graduação Stricto Sensu em Educação Física da Universidade Católica de Brasília (UCB), como parte dos requisitos para a obtenção do título de Mestre em Educação Física.

Orientador: Prof. Dr. Herbert Gustavo Simões

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AGRADECIMENTO

A Deus por me presentear com a vida e por meio dela conhecer e conviver com pessoas que tanto amo e desejo toda felicidade.

Agradeço aos meus pais Wilson Sotero Junior e Selene Maria da Costa Sotero e aos meus irmãos Marina e Fabio da Costa Sotero que amo e são exemplos na minha vida.

Com carinho, aos meus “pais” acadêmicos e também amigos Prof. Dr. Herbert G. Símões e a Prof. Dr. Carmen S. G. Campbell, muito obrigado pelos ensinamentos acadêmicos e de vida que pude tanto aprender com vocês.

Aos meus familiares e amigos desejo que Deus abençoe todos com muita saúde, paz, sabedoria e felicidades.

Ao Conselho Nascional de Desenvolvimento Científico e Tecnológico (CNPq), pela concessão de bolsa de Iniciação Científica (IC) e à Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)/Programa de Suporte à Pós-graduação de Instituições de Ensino Particulares (PROSUP), pela concessão de bolsa em nível de mestrado.

“Deus abençoe a todos” (Deus et al., 0)

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ÍNDICE

1. RESUMO... 06

2. ABSTRACT... 07

3. INTRODUÇÃO... 08

4. OBJETIVOS... 10

5. REVISÃO DE LITERATURA... 11

5.1 Lactato Sanguíneo... 11

5.1.1 Resposta do Lactato Sanguíneo ao Exercício... 11

5.2 Máximo Estado Estável do Lactato Sanguíneo (MEEL)... 11

5.3 Protocolo do Lactato Mínimo (LM)... 12

5.4 Protocolo da Glicemia Mínima (GM)... 13

5.5 Identificação do LM por inspeção visual e por ajuste matemático... 13

6. ARTIGOS PUBLICADOS... 15

6.1 Indirect assessment of lactate minimum and maximal blood lactate steady-state intensity for physically active individuals... 15

6.2 Polynomial adjustment as a new technique for determination of lactate minimum velocity with reduced blood sampling... 23

6.3 Blood glucose minimum predicts maximal lactate steady state on running... 30

7. ARTIGO SUBMETIDO À PUBLICAÇÃO- Aerobic evaluation can be done in youth runners by performing only three incremental stages of lactate minimum test... 35

8. CONCLUSÕES... 59

9. REFERÊNCIAS BIBLIOGRÁFICAS... 60

10. ANEXOS... 65

10.1 Anexo 1 - Processo de revisão do artigo: Indirect assessment of lactate minimum and maximal blood lactate steady-state intensity for physically active individuals ... 65

10.1.1 Carta de submissão... 65

10.1.2 Carta resposta (processo de revisão)... 65

10.1.3 Carta de aceite... 74

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technique for determination of lactate minimum velocity with reduction blood

sampling... 75

10.2.1 Carta de submissão... 76

10.2.2 Carta resposta (processo de revisão)... 76

10.2.3 Carta de aceite... 76

10.3 Anexo 3 - Processo de revisão do artigo: Blood glucose minimum predicts maximal lactate steady state on running... 78

10.3.1 Carta de submissão... 78

10.3.2 Carta resposta (processo de revisão)... 78

10.3.3 Carta de aceite... 96

10.4 Anexo 4 - Processo de revisão do artigo: Aerobic evaluation can be done in youth runners by performing only three incremental stages of lactate minimum test... 98

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1. RESUMO

MÉTODOS DE DETERMINAÇÃO DIRETO E INDIRETO DO MÁXIMO ESTADO ESTÁVEL DE LACTATO EM PISTA DE ATLETISMO

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2. ABSTRACT

DIRECT AND INDIRECT METHODS OF DETERMINATION OF THE MAXIMAL LACTATE STEADY STATE IN TRACK ATHLETES

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3. INTRODUÇÃO

Os protocolos de identificação do máximo estado estável de lactato (MEEL) têm sido estudados por diversos pesquisadores (Kindermann et al., 1979; Davis et al., 1979; Campbell et al., 1996; Simões et al., 1998; MacIntosh et al., 2002; Souza et al., 2003), e sua utilização tem sido de grande eficácia na prescrição de níveis de treinamento e predição da performance atlética (Kindermann et al., 1979; Snyder et al., 1994; Weltman, 1995).

Dentre os diversos métodos que se propõem a predizer e/ou determinar a velocidade de corrida correspondente ao MEEL temos, respectivamente, o protocolo do Lactato Mínimo (LM) (Souza et al., 2003) e a identificação direta do MEEL por meio de 3 a 5 séries de exercício retangular com mensuração periódica de lactato sangüíneo (Bacon & Kern, 1999).

A intensidade correspondente ao LM em testes de corrida é determinada como sendo a velocidade associada à menor concentração de lactato durante teste incremental após indução de hiperlactatemia (Souza et al., 2003), enquanto o MEEL é definida como a maior intensidade de exercício em que a [Lac] varia menos que 1mM entre 10 e 30 minutos de exercício (MacIntosh et al., 2002; Bacon & Kern, 1999). Simões et al. (1999), trabalhando com o protocolo do LM em corredores fundistas, observaram ser possível, durante a realização do teste, determinar a intensidade do LM (ILM) por meio da resposta da glicemia dos voluntários, por apresentar similar comportamento ao do lactato sanguíneo durante o teste incremental, propondo então a identificação do LM a partir da Glicemia Mínima (GM), sendo essa validada com o MEEL (Sotero et al., 2009).

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fisicamente ativos (Sotero et al., 2009, 2009B), vêm proporcionando uma diminuição dos custos e uma maior praticidade para determinação das intensidades de exercício associadas ao LM e ao MEEL.

Tradicionalmente o LM tem sido identificado por inspeção visual a partir da resposta do [Lac] durante o teste incremental (Carter et al.,1999; Jones & Doust, 1998; Simões et al., 1999). Entretanto, modelos matemáticos têm sido empregadas para ajustar a cinética do [Lac] e identificar com maior precisão a ILM. Durante esse teste a [Lac] se apresenta em forma de parábola (U shaped) possibilitando a aplicação de ajustes matemáticos para o cálculo da abscissa do vértice da equação gerada. Dentre os ajustes utilizados, podemos citar a função cúbica (Ribeiro et al., 2003) e a função quadrática, também denominada de função polinomial de segunda ordem (MacIntosh et al., 2002; Pardono et al., 2006; Sotero et al., 2006; Simões et al., 2005; Voltarelli et al., 2004), além da análise obtida a partir de spline function (Voltarelli et al., 2002; Jones and Doust et al., 1998; Tegtbur et al., 1993).

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4. OBJETIVOS

A presente dissertação de mestrado foi originada a partir de um projeto de pesquisa que resultou em 4 artigos científicos, cujos objetivos foram:

1. Elaborar e validar uma equação de predição das intensidades do LM e da MEEL em indivíduos não atletas (SOTERO RC, PARDONO E, CAMPBELL CSG, SIMOES HG. Indirect assessment of lactate minimum and maximal blood lactate steady state intensity. Journal of Strength and Conditioning Research, v. 23, p. 847-853, 2009);

2. Comparar as intensidades de corrida correspondentes à GM, ao LM e ao MEEL em

indivíduos fisicamente ativos (SOTERO RC, PARDONO E, LANDWEHR R, CAMPBELL CSG, SIMOES HG. Blood glucose minimum predicts maximal lactate steady state. International Journal of Sports Medicine, v. 30, p. 643-646, 2009);

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5. REVISÃO DE LITERATURA 5.1 Lactato Sanguíneo

O lactato é um metabólito originado ao final da glicólise, predominantemente quando a quantidade de oxigênio celular é insuficiente para a manutenção do ciclo dos ácidos tricarboxílicos. Devido a essa insuficiência de O2, o piruvato deixa de se converter em Acetil-Coa para se converter em lactato (Lehninger et al., 2006).

5.1.1 Resposta do Lactato Sanguíneo ao Exercício

A resposta de lactato sanguíneo ao exercício constitui um índice capaz de avaliar um indivíduo aeróbio e anaerobiamente. Durante um exercício de cargas progressivas no qual a capitação de O2 é suficiente para manutenção do sistema energético aeróbio, ocorre uma maior remoção do que produção de lactato. Em um dado momento do exercício, a produção e remoção de lactato se igualam correspondendo assim à intensidade da máxima fase estável de lactato. Quando a intensidade do exercício ultrapassa esse ponto de equilíbrio, ocorre uma maior produção em relação à remoção de lactato. Esse aumento na produção reflete o aumento da acidose metabólica provocada pelos íons de hidrogênio (H+) (Marzzoco & Torres, 1999; Denadai et al., 2000).

5.2 Máximo Estado Estável do Lactato (MEEL)

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intensidade apresenta equivalência com a intensidade correspondente aos limires ventilatório, de lactato e glicêmico (Baron et al., 2003; Sotero et al., 2009).

Figura 1. Comportamento da [Lac] durante corrida constante de 30 min. (MEEL) (Sotero et

al., 2009B).

5.3 Protocolo do Lactato Mínimo (LM)

Uma forma de se identificar a velocidade correspondente ao MEEL se dá por meio do teste do lactato mínimo (MacIntosh et al., 2002; Souza et al., 2003). O protocolo do LM consiste em um teste incremental, após indução à hiperlactatemia, no qual a intensidade de exercício correspondente à menor concentração de lactato é considerada o ponto de equilíbrio entre produção e remoção de lactato (Tegtbur et al., 1993; Simões et al., 2003) (Figura 2).

Figura 2. Comportamento do lactato sanguíneo em teste de corrida após indução à

13 3.5 4 4.5 5 5.5 6 Sprint 150m

201.7 213.3 221.2 229.7 235.3 241.2

Running velocity (m.min-1)

B lo o d l a c ta te ( m m o l. L -1) 65 70 75 80 85 90 95 100 105 B lo o d g lu c o s e ( m g .d l -1 ) LM GM 5.4 Protocolo da Glicemia Mínima (GM)

Similarmente ao protocolo do LM, a concentração da glicemia [Glic], durante o teste incremental, também apresenta um ponto mínimo, associado às intensidades de LM e do MEEL (Simões et al., 1999; Sotero et al., 2009) (Figura 3).

Figura 3. Comportamento da glicemia em teste de corrida após indução à hiperlactatemia, no

qual a menor concentração de glicemia corresponde à GM (Sotero et al., 2009).

5.5 Identificação do LM por inspeção visual e por ajuste matemático

A velocidade de corrida correspondente à menor concentração de lactato sanguíneo durante o teste incremental pode ser determinada por inspeção visual e/ou se aplicando função polinomial de segunda ordem (LMp) (MacIntosh et al., 2002; Sotero et al., 2007).

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Equação de 2ª grau: y = a. x2 - b. x + c

Derivada da equação: 0 = 2a . x – b onde a e b são constantes da equação e x a velocidade correspondente ao vértice da parábola, ou seja, ILM, sendo assim determinada (Figura 4): x = -b_ ou ILM = -b_

2.a 2.a

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6. ARTIGOS PUBLICADOS

6.1 Indirect assessment of lactate minimum and maximal blood lactate steady-state intensity for physically active individuals

Referência:

SOTERO RC; PARDONO E; CAMPBELL CSG; SIMOES HG. Indirect assessment of lactate minimum and maximal blood lactate steady state intensity. Journal of Strength and Conditioning Research, v. 23, p. 847-853, 2009.

Dados da periódico:

Editor(es) Científico(s): National Strength and Conditioning Association (NSCA) Área(s): Educação Física e Esportes

Tipo de Material: Periódicos com texto completo Qualis Nacional: A2

Forma de Aquisição: Assinado Analisado JCR 2008: sim

Fator de Impacto: 0.815 (JCR-2008) Número de citações: 1,681

Editor/distribuidor: EBSCO ISSN: 1064-8011

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6.2 Polynomial adjustment as a new technique for determination of lactate minimum velocity with reduced blood sampling

- Referência:

SOTERO RC; CAMPBELL CSG; PARDONO E; PUGA GM; SIMOES HG. Polynomial adjustment as a new technique for determination of lactate minimum velocity with reduced blood sampling. Revista Brasileira de Cineantropometria & Desempenho Humano, v. 4, p. 321-326, 2007.

- Dados da periódico:

Editor(es) Científico(s): Universidade Federal de Santa Catarina (UFSC) Área(s): Ciências da Saúde (Geral), Educação Física e Esportes

Tipo de Material: Periódicos com texto completo Qualis Nascional: B2

Forma de Aquisição: Livre acesso Analisado JCR 2008: não

Editor/distribuidor: Outros editores ISSN: 1415-8426

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6.3 Blood glucose minimum predicts maximal lactate steady state on running

- Referência:

SOTERO RC; PARDONO E; LANDWEHR R; CAMPBELL CSG; SIMOES HG. Blood glucose minimum predicts maximal lactate steady state. International Journal of Sports Medicine, v. 30, p. 643-646, 2009.

- Dados da periódico:

Área(s): Fisiatria. Medicina Física. Reabilitação Tipo de Material: Periódicos com texto completo Qualis Nascional: A1

Forma de Aquisição: Assinado Analisado JCR 2008: sim

Fator de Impacto: 1.626 (JCR-2008) Número de citações: 4,418

Editor/distribuidor: Thieme ISSN: 0172-4622

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7. ARTIGO SUBMETIDO À PUBLICAÇÃO- Aerobic evaluation can be done in youth runners by performing only three incremental stages of lactate minimum test

Referência:

SOTERO RC; CUNHO VNC; MADRID B; SALES MM; MOREIRA SR; SIMOES HG. Aerobic evaluation can be done in youth runners by Performing only three incremental stages of lactate minimum test. Prelo. Revista Brasileira de Medicina do Esporte, 2010.

Dados da periódico:

Editor(es) Científico(s): Sociedade Brasileira de Medicina do Esporte

Área(s): Medicina (Geral) Fisiatria. Medicina Física. Reabilitação Fisioterapia, Terapia Ocupacional e Educação Física e Esportes

Tipo de Material: Periódicos com texto completo Qualis Nascional: B1

Forma de Aquisição: Livre acesso Analisado JCR 2008: não

Editor/distribuidor: SciELO Scientific Electronic Library Online ISSN: 1517-8692

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8. CONCLUSÕES

Foi possível concluir a partir dos resultados dos estudos que:

1) A velocidade de corrida determinada pela equação de predição a partir do desempenho de 1600m não diferiu das intensidades de LM e de MEEL, validando sua aplicação e utilização de maneira não invasiva para prescrição de treinamento em indivíduos não atletas;

2)

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9. REFERÊNCIAS BIBLIOGRÁFICAS

BACON L, and KERN M. Evaluating a test protocol for predicting maximum lactate steady state. Journal Sports Medicine Physicol Fitness, v.39, p.300-308, 1999.

BARON B, DEKERLE J, ROBIN S, NEVIERE R, DUPONT L, MATRAN R, VANVELCENAHER J, ROBIN H, PELAYO P. Maximal lactate steady state does not correspond to a complete physiological steady state. International Journal Sports Medicine, v.24, p.582-587, 2003.

CAMPBELL CSG, SIMÕES HG, KOKUBUN E, DENADAI BS, BALDISSERA V. Reproducibility of individual anaerobic threshold (IAT) and lactate minimum (LM) in track test. In: International Pre-Olympic Scientific Congress, Dallas, 1996. Abstracts’ Book. Dallas, International Council of Sports Science and Physical Education, p.114, 1996.

CARTER H, JONES AM, and DOUST JH. Effect of incremental test protocol on the lactate minimum speed. Medicine and Science Sports and Exercise, 31: 837–845, 1999.

DAVIS HA. and GASS GC. Blood lactate concentrations during incremental work before and after maximum exercise. Brazilian Journal Sports Medicine, v.13: p.165-169, 1979.

DENADAI BS. Avaliação aeróbia: determinação indireta da resposta do lactato sanguíneo. Rio Claro: Motrix, 2000.

DINIZ JR, SAKUMA KC, OLIVEIRA F, MARCON F, PACHECO ME, SILVA LGM, SIMÕES HG, CAMPBELL CSG. Accuracy of the lactate minimum predictive equation for young swimmers In: 7 th Annual Congress of the European College of Sport Science, Athens, 2002.

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JONES AM. and DOUST JH. The validity of the lactate minimum test for determination of the maximal lactate steady state and physiological correlates to 8 Km running performance. Medicine and Science in Sports and Exercise, v.30, p.509-518, 1998.

KINDERMAN W, SIMON G and KEUL J. The siginificance of the aerobic-anaerobic transitions for determination of workload intensities during endurance training. European Journal Applied Physiology, v.42, p.25-34, 1979.

LEHNINGER A, NELSON DL, COX MM. Princípios de bioquímica. 4. ed. São Paulo: Sarvier, 2006.

MACINTOSH BR, ESAÚ S, and SVEDAHL K. The lactate minimum test for cycling: Etimation of the maximal lactate steady state. Canadian Journal of Applied Physiology. 27(3): p.232-249, 2002.

MARZZOCO A, TORRES BB. Bioquímica básica. 2. ed Rio de Janeiro: Guanabara Koogan, 1999.

PARDONO E, SOTERO RC, HIYANE W, MOTA MR, CAMPBELL CS, NAKAMURA FY, SIMÕES HG. Maximal Lactate Steady State Prediction Through Polynomial Modeling of the Three Stages Lactate Minimum Test. Medicine and Science in Sports and Exercise, 38:505, 2006.

RIBEIRO L, BALIKIAN P, MALACHIAS P, BALDISSERA V. Stage length, spline function and lactate minimum swimming speed. Journal Sports Medicine Physicol Fitness, 43(3):312-18, 2003.

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young soccer players In: 7 th Annual Congress of the European College of Sport Science, Athens, 2002.

SIMÕES HG, DENADAI BS, BALDISSERA V, CAMPBELL CS, HILL DW. Relationships and significance of lactate minimum, critical velocity, heart rate deflection and 3000 m track-tests for running. Journal Sports Medicine Physicol Fitness, 45(4):441-51, 2005.

SIMÕES HG, CAMPBELL CS, KUSHNICK MR, NAKAMURA A, KATSANOS CS, BALDISSERA V, and MOFFATT RJ. Blood glucose threshold and the metabolic responses to incremental exercise tests with and without prior lactic acidosis induction. European Journal Applied Physiology, 89: 603–611, 2003.

SIMÕES HG, CAMPBELL CSG, BALDISSERA V, MAZIERO DC, MELLO F, TANGO MH. Lactate minimum test in swimming : relationship to performance and maximal lactate steady state. Medicine and Science in Sports and Exercise Supplement, USA, 2000.

SIMÕES HG, GRUBERT CAMPBELL CS, KOKUBUN E, DENADAI BS, BALDISSERA V. Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests. European Journal Applied Physiology Occup Physiol, 80(1):34-40, 1999.

SIMÕES HG, CAMPBELL CSG, DENADAI BS, KOKUBUN E, BALDISSERA V. Determinação do limiar anaeróbio por meio de dosagens e glicêmicas e lactacidêmicas em testes de pista para corredores. Revista Paulista de Educação Física, v.12, p.17-30, 1998.

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SIMÕES HG, CAMPBELL CSG, DENADAI BS, KOKUBUN E, BALDISSERA, V. Indirect assessment of anaerobic threshold in track test for endurance runners. Abstract book of the 1996 International Pre- Olympic Scientific Congress, Dallas – Texas, EUA, 1996.

SNYDER AC, WOULFE T, WELSH R, FOSTER C. A simplified approach to estimating the maximal lactate steady state. Ind. J. Sports Medicine, v.15, p.27-31, 1994.

SOTERO RC, PARDONO E, LANDWEHR R, CAMPBELL CSG, SIMOES HG. Blood glucose minimum predicts maximal lactate steady state. International Journal of Sports Medicine, v. 30, p. 643-646, 2009.

SOTERO RC, PARDONO E, CAMPBELL CSG, SIMOES HG. Indirect assessment of lactate minimum and maximal blood lactate steady state intensity. Journal of Strength and Conditioning Research, v. 23, p. 847-853, 2009B.

SOTERO RC, CAMPBELL CSG, PARDONO E, PUGA GM, SIMOES HG. Polynomial adjustment as a new technique for determination of lactate minimum velocity with reduced blood sampling. Revista Brasileira de Cineantropometria & Desempenho Humano, v. 4, p. 321-326, 2007.

SOUZA TNT, YAMAGUTI SA, ALEXANDRE L, CAMPBELL CSG, SIMÕES HG. Identificação do lactato mínimo e glicose mínima em indivíduos fisicamente ativos. Revista Brasileira de Ciência e Movimento, v.11, p.71-75, 2003.

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TEGTBUR U, BUSSE MW, and BRAUMANN KM. Estimation of an individual equilibrium point between lactate production and remotion during exercise. Medicine and Science in Sports and Exercise, v.25, p.620-7, 1993.

VOLTARELLI FA, MELLO MAR, GOBATTO CA. Limiar anaeróbio determinado pelo teste do Lactato mínimo em ratos: efeito dos estoques de glicogênio muscular e do treinamento físico. Revista Portuguesa de Ciência do Desporto, 2004; 4(3): 16-25.

VOLTARELLI FA, GOBATTO CA and MELLO MAR. Determination of anaerobic threshold in rats using the lactate minimum test. Brazilian Journal of Medical and Biological Research, 35(11):1389-94, 2002.

WELTMAN A. The blood lactate response to exercise – Current issues in exercise science. Monograph Number 4, Human Kinetics, 1995.

8. ANEXOS

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10. ANEXOS

10.1 Anexo 1 - Indirect assessment of lactate minimum and maximal blood lactate steady-state intensity for physically active individuals

10.1.1 Carta de submissão

Dear Dr. William J. Kraemer

The manuscript entitled: “Indirect assessment of lactate minimum and maximal blood lactate steady state intensity” is addressed for first analysis in JSCR.

This manuscript contains material that is original and not previously published in text or on the Internet, nor is it being considered elsewhere until a decision is made as to its acceptability by the JSCR Editorial Review Board.

The address for correspondence is:

Prof Rafael da Costa Sotero and Prof Herbert Gustavo Simões Universidade Católica de Brasília

Programa de Mestrado e Doutorado em Educação Física – Sala G 119 QS07 LT1 EPCT, Águas Claras, Taguatinga – DF, Brasil

ZIP code: 72022-900

Phones: 55 61 33569350 / 55 61 33569330 Fax: 55 61 33569350 / 55 61 33440098 E-mails: rafasotero@gmail.com

10.1.2 Carta resposta (processo de revisão)

From: NSOE - JSCR < jscr@uconn.edu> Date: 29/10/2007 12:04

Subject: JSCR Request for Revisions To: rafasotero@gmail.com

R- 25337

Dear Dr . Sotero,

Please use the title, first author, and corresponding author, and this R number and its revision state when communicating with our office. It is important that this information is on the paper as well.

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point must be addressed before it can be considered for publication in the Journal of Strength and Conditioning Research.

Therefore, I invite you to respond to the reviewers' comments and submit a revision if you believe you can adequately address their concerns. Please note that this request for revision does not imply that the manuscript will ultimately be accepted, but that the manuscript must be revised before further consideration is provided.

Obviously, your revised submission must include an itemized, point-by-point response to each the comments of the reviewers. The revised manuscript will be sent to the original reviewers for another evaluation before a decision is made. You also need to carefully check your JSCR journal format as this will just delay publication if it is not correct.

You now can email your revision to us at jscr@uconn.edu. Please contact us at this email if you need further assistance.

You must make sure you send the response to the reviewers, manuscript (with R number and revision number on it), figures, tables, copyright (if you have not already sent it in with your initial submission).

Receipt of your revised manuscript will be acknowledged by email. Our new publisher is LWW and we will be going to 6 journals a year to speed publication and reduce in press time.

Thank you for your contribution to the JSCR. Sincerely,

Amanda K. Hopkins Staff

Joan M. Kraemer, BA Editorial Assistant

Journal of Strength and Conditioning Research

The Journal of Strength and Conditioning Research has been a PUBMED, Medline journal since 2001. A full ar chive of all papers is on the NSCA web site at www.nsca-lift.org . ================================================================ REVIEWS

===============================================================

The Journal of Strength and Conditioning Research

Manuscript Number R-25337

Responses to the comments of Reviewer #1

Dear reviewer #1,

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included as well. For instance, a discussion regarding the limitations of the study

was added on page 11 of the manuscript. Furthermore, the paper was revised

(English revision) by a native English speaker, an American who is a Professor

in languages. Overall, we believe the paper is better now. Below are the main

changes as a result of the reviewer’s comments and their locations in the

manuscript.

1. So both groups were different or the same group? Unclear. Clarify.

We agree that the experimental design needed clarification. Accordingly both the Abstract and Methods sections have been modified for improved clarity. In addition, a representative scheme of the Experimental Design was included (see page 21 of manuscript). The following paragraphs reflect the main changes regarding the first request of the referee #1:

ABSTRACT

“…were analyzed on twenty-two physically active men (24.6±4.1 years; 72.6±8.0 Kg; 1.75±0.1 m; 11.9±3.7% body fat). The participants were allocated in two different groups (G1 and G2). The running velocities (m.min-1) corresponding to the 1600-m time trial (1600mV) and lactate minimum (LM) were determined on G1 (n=12), while the G2 participants (n=10) had the MLSS identified in addition to 1600mV and LM tests. ” (Page 3, lines 3 to 8 from Abstract)

“The relationship between 1600mV and LM for G1 yielded the following equation for indirect assessment of the LM velocity: LMind (m.min-1) = (0.7507*1600mV) + 21.575. The validity of the LMind was tested in the participants of G2 by comparing to the MLSS..” (Page 3, lines 10 to 13 of Abstract)

METHODS

“Experimental Approach to the Problem

Twenty two physically active young males volunteered to take part in this investigation. The research was initially conducted as Study 1 (group 1, G1) with the purpose of elaborating a predictive equation for LM running velocity. Study 2 was then conducted with another group of participants (group 2, G2) in order to analyze the validity of the predictive equation (as obtained in Study 1 for G1) to identify the exercise intensity corresponding to LM and MLSS velocities”. (Page 5, lines 2 to 8 of Methods – Experimental Approach to the Problem)

“Subjects

A group of twelve participants took part in Study 1 (G1) and another group of ten individuals participated in Study 2 (G2) after having signed … ” (Page 5, lines 16 to 18 from Methods)

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Scheme 1 (experimental design) and Table 1 (with the characteristics of the participants) are now on pages 21 and 29 of the manuscript respectively. Table 1 presents information of both groups studied (G1 – Study 1; G2 – Study 2). From the above mentioned changes we expect that the manuscript is now clearer as requested.

2. The study is complex and the abstract practical applications are not clear in the abstract.

The present study aimed to determine an equation to estimate the running velocity corresponding to LM and to MLSS for physically active individuals on a running track, so the authors believe that with this equation the coaches or trainers would be able to use it as a practical and economical alternative, particularly for those that don’t have laboratorial facilities. Thus, the last sentence of the Abstract was changed to support these practical applications.

“…,, thus being a practical and economical alternative to trainers that can not directly determine the MLSS”.” (Page 3, lines 20 to 21 from Abstract)

3. The introduction needs to develop the hypothesis of the study in a clear manner. At times it is hard to understand.

We agree. The Introduction now has a clearer hypothesis as indicated in the 3rd paragraph of the Introduction:

“Since LM and MLSS are expected to occur at similar exercise intensities (1,5,9,11) and have been well correlated to middle distance performance (4,10,13), it was hypothesized that the LM and thus the MLSS intensity would be estimated for physically active non-competitive individuals from the 1600-m running performance.”

(Page 4, 3rd paragraph of Introduction)

4. You need to better qualify for context the activity and fitness level and training background of the subjects used in the investigation.

The activity and fitness levels and training background of the subjects were included in the text. This information is in the Subjects section, page 5 line 20 to page 6 line 4 (see below). Also, in addition to this referee’s request, we estimated the VO2

peak of the participants according to their results of 1600-m running performance, following procedures described by Cureton et al (14). It was done for a better characterization of the participants as requested (Cureton KJ et al. A generalized equation for prediction of VO2peak from 1-mile run/walk performance. Med. Sci. Sports. Exerc. 27:445-51. 1995).

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5. Did they sign an informed consent document as part of the ethics committee requirement? Clarify and add.

Ok. It was already added as follows.

“A group of twelve participants took part in Study 1 (G1) and another group of ten individuals participated in Study 2 (G2) after having signed an informed consent form stating both the risks and benefits of their participation. The local Ethics Committee for Human Research approved the methods involved in this study (nº 019/2004).” (Page 5, lines 16 to 19 from Methods)

6. Did you do any reliability testing for the dependent measures? ICCRs?

We and other researchers have done previous studiesregarding the reliability of the LM test (CAMPBELL et al. 1998; MACINTOSH et al. 2002; SIMÕES et al. 1997). Other studies also have shown the LM to be reliable and valid to estimate MLSS (BENEKE et al. 2003; SOTERO et al. 2007). Also, the middle distance performance, as 1600-m running in present study, have been shown to be reproducible both for children and adults regardless of whether they are athletes or physically activenon-athletes(CAMPBELL et al. 1998; LAURSEN et al. 2007; RIKLI et al. 1992; SIMÕES et al. 1997). Information regarding these concerns is now on page 10 line 13 to 18 of the Discussion section. The dissertation of the paper regardingthis subject, as well as in general, is now clear as suggested.

7. So were the G2 subjects same as the G-1 or different group? You need to clarify this and then give their backgrounds as well.

As answered for comment/question#1 (see page 1 of this letter), G1 and G2 were not the same. The authors improved these points in the Methods section and the participants’ backgrounds are now described in table 1.

Table 1. Age (years) Weight (kg) Height (m) Body Fat (%) VO2peak (mL.kg-1.min-1)

G1 (n=12) 23.5 (3.6) 71.5 (7.2) 1.76 (0.1) 10.3 (2.4) 53.5 (3.1) G2 (n=10) 25.9 (4.5) 73.9 (9.0) 1.75 (0.1) 13.8 (4.3) 52.8 (3.4) (Page 27)

8. Statistical Analyses, not analysis, check all formatting.

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9. Why is P = 0.05 not significant?

Ok. The authors changed for p<0.05.

10. Do not bullet the practical applications and make them clear to the coach or end user.

The bullets were deleted. We also altered the first and second paragraphs to enable better comprehension. We tried to construct our Practical Applications as follows: Why to use the LMind; Suggestions about training sessions (relationship between volume and intensity) using LMind; How these intensities could be connected to exercise prescription within different exercise intensity domains.

Practical Applications

“The proposed predictive equation for lactate minimum intensity: “LMind (m.min-1) = (0.7507 * 1600mV) + 21.57”, may enable the prediction of the running velocity associated with the maximal blood lactate steady state. Thus coaches or trainers may benefit from this predictive equation since it is a practical and less expensive method while the costs of the direct determination of LM/MLSS are elevated due the laboratory equipment and technicians dealing with blood lactate measurements.

The results of the present study would be applied in several ways. For example, after a 1600-m perfor1600-mance test is co1600-mpleted, the LM intensity would be esti1600-mated (LMind) and then so1600-me sessions of running training would be prescribed on an individual basis as follows:

- Moderate intensity running: 30 to 50 minutes at a velocity below LMind (e.g. 90 to 95% LMind);

- Moderate to high intensity running: 20 to 30 minutes at a velocity slightly above but not higher than 3% above LMind;

- High intensity running: 10 to 20 minutes of exercise at a velocity ~ 5% above LMind. - Alternatively, a very high intensity running session, at a velocity 10 to 20% above

LMind (which is around 95-100% of 1600mV, respectively), would also be done to improve performance. For this last, the utilization of 2-4 bouts of 4 to 5 minute exercise with ~4–8 minutes rest would be useful with the purpose of reaching the VO2max during the exercise session.

Finally, in general 3 to 5 aerobic sessions per week are recommended, with no more than 2 sessions being done at an intensity above LMind. Those high or very high intensity exercise sessions would be alternated with moderate intensity exercise sessions (e.g. below LMind).” (Page 12 and 13 from Practical Applications section)

Responses to the comments of Reviewer #2

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The experimental design was carefully revised, and the Methods section was changed for better comprehension. The changes included the position of the figures and tables besides the inclusion of a representative scheme of the procedures (experimental design) as suggested by this referee. Scheme 1 (experimental design) and Table 1 (with the characteristics of the participants) are now on pages 21 and 29 of the manuscript respectively. Table 1 presents information of both groups studied (G1 – Study 1; G2 – Study 2). From the above mentioned changes we expect that the manuscript is now clearer as requested.

ABSTRACT

“…were analyzed on twenty-two physically active men (24.6±4.1 years; 72.6±8.0 Kg; 1.75±0.1 m; 11.9±3.7% body fat). The participants were allocated in two different groups (G1 and G2). The running velocities (m.min-1) corresponding to the 1600-m time trial (1600mV) and lactate minimum (LM) were determined on G1 (n=12), while the G2 participants (n=10) had the MLSS identified in addition to 1600mV and LM tests. ” (Page 3, lines 3 to 8 from Abstract)

“The relationship between 1600mV and LM for G1 yielded the following equation for indirect assessment of the LM velocity: LMind (m.min-1) = (0.7507*1600mV) + 21.575. The validity of the LMind was tested in the participants of G2 by comparing to the MLSS..” (Page 3, lines 10 to 13 of Abstract)

METHODS

“Experimental Approach to the Problem

Twenty two physically active young males volunteered to take part in this investigation. The research was initially conducted as Study 1 (group 1, G1) with the purpose of elaborating a predictive equation for LM running velocity. Study 2 was then conducted with another group of participants (group 2, G2) in order to analyze the validity of the predictive equation (as obtained in Study 1 for G1) to identify the exercise intensity corresponding to LM and MLSS velocities”. (Page 5, lines 2 to 8 of Methods – Experimental Approach to the Problem)

“Subjects

A group of twelve participants took part in Study 1 (G1) and another group of ten individuals participated in Study 2 (G2) after having signed … ” (Page 5, lines 16 to 18 from Methods)

2. The development of the hypothesis needs to be clearly developed leading to the experimental approach to the problem showing how the design will allow the author(s) to test the hypothesis(s).

We agree with the reviewer and believe that the Introduction needed a clearer hypothesis. Therefore, the following text was added:

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that the LM and thus the MLSS intensity would be estimated for physically active non-competitive individuals from the 1600-m running performance.”

(Page 4, 3rd paragraph of Introduction)

4. The subjects background and informed written consent needs to be clear and the equipment and methods need to be clearly defined for replication of the study.

Information regarding the ethics approval and written consent of the subjects was included in the text. The activity and fitness levels and training background of the subjects were included in the text too.

All information regarding the participants’ background is now in the Subjects section, page 5 line 20 to page 6 line 4 (see below). Also, in addition to this referee’s request, we estimated the VO2 peak of the participants according to their results of

1600-m running performance, following procedures described by Cureton et al (14). It was done for a better characterization of the participants as requested (Cureton KJ et al. A generalized equation for prediction of VO2peak from 1-mile run/walk performance. Med. Sci. Sports. Exerc. 27:445-51. 1995).

“All volunteers were physically active males (engaged in a minimum of 30-min of physical exercise at least three times a week for non-competitive purposes). These participants were Physical Education students that used to exercise on a recreational basis as well as for practical classes. Their VO2peak was predicted according to Cureton et al. (14) from the time they would spend to complete a mile running test. The main characteristics of the participants of Group 1 ( Study 1) and Group 2 (Study 2) are described in Table 1 and the general procedures of the studies 1 and 2 are detailedin Scheme 1.”(Page 5, lines 20 to page 6 line 3 from Methods)

Information about informed consent was also included as follow:

. “A group of twelve participants took part in Study 1 (G1) and another group of ten individuals participated in Study 2 (G2) after having signed an informed consent form stating both the risks and benefits of their participation. The local Ethics Committee for Human Research approved the methods involved in this study (nº 019/2004).” (Page 5, lines 16 to 19 from Methods)

5. The reliability of the measures needs to be clear and the writing style needs to be concise to the point of exacting clarity.

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5. The discussion needs to reflect the hypothesis(s) tested and the practical applications needs to be clear for the use by the coach or trainer.

The authors believe that the discussion should reflect the hypothesis, This was done in this revised version. Also, the practical applications section was improved accordingly. So, both a part of the discussion regarding the hypothesis and practical applications are now improved as follows:

Discussion

…..“The MLSS has been considered as the gold standard among the protocols of functional assessment from the responses of blood lactate (28). In the present study there were no significant differences between the running velocities corresponding to LM, LMind and MLSS (p>0.05) (Table 2). Additionally, high correlations were observed between the LM, LMind and MLSS velocities, and the technique of Bland and Altman (16) showed an agreement between the LM-LMind and MLSS-LMind (Figure 3). So, while the costs of laboratory equipment and technicians dealing with blood collection and analyses for determining the LM and/or MLSS are elevated, the LMind is a practical and less expensive method that would enable the prediction of the MLSS and LM. Such predictive method was shown to be an accurate alternative for coaches or trainers to prescribe exercise intensities that would be sustained without blood lactate accumulation.

Finally, the findings of the present study indicate that both LM and LMind are valid estimates of running velocities associated with MLSS (Table 3) if determined on individuals with characteristics similar to the participants of the present study. So, it was concluded that the proposed equation: (LMind = (0.7507 * 1600mV) + 21.575) may be applied to estimate the running velocity (m.min-1) corresponding to LM and MLSS from the 1600-m running performance on young physically active individuals. Further studies should be done in order to formulate other predictive equations for different populations and from different running distances that would be sub-maximal instead of maximal.

The authors agree that the Practical Applications should be clearer, so we altered its first and second paragraphs for a more comprehensible sequence. We tried to construct our Practical Applications as follows: Why to use the LMind; Suggestions about training sessions (relationship between volume and intensity) using LMind; How these intensities can be connected to exercise domains.

Practical Applications

“The proposed predictive equation for lactate minimum intensity: “LMind (m.min-1) = (0.7507 * 1600mV) + 21.57”, may enable the prediction of the running velocity associated with the maximal blood lactate steady state. Thus coaches or trainers may benefit from this predictive equation since it is a practical and less expensive method while the costs of the direct determination of LM/MLSS are elevated due the laboratory equipment and technicians dealing with blood lactate measurements.

The results of the present study would be applied in several ways. For example, after a 1600-m perfor1600-mance test is co1600-mpleted, the LM intensity would be esti1600-mated (LMind) and then so1600-me sessions of running training would be prescribed on an individual basis as follows:

74

- Moderate to high intensity running: 20 to 30 minutes at a velocity slightly above but not higher than 3% above LMind;

- High intensity running: 10 to 20 minutes of exercise at a velocity ~ 5% above LMind. - Alternatively, a very high intensity running session, at a velocity 10 to 20% above

LMind (which is around 95-100% of 1600mV, respectively), would also be done to improve performance. For this last, the utilization of 2-4 bouts of 4 to 5 minute exercise with ~4–8 minutes rest would be useful with the purpose of reaching the VO2max during the exercise session.

Finally, in general 3 to 5 aerobic sessions per week are recommended, with no more than 2 sessions being done at an intensity above LMind. Those high or very high intensity exercise sessions would be alternated with moderate intensity exercise sessions (e.g. below LMind).”

(Page 12 and 13 from Practical Applications section)

6. Figures are on one page each with a legends page before it and the formatting for the journal should be precise.

OK

7. In general this paper needs fine tuning and attention to details and writing style and it should be a contribution to the literature if the ambiguities can be removed, lack of clarity improved, and details of experimental design enhanced.

The manuscript has been significantly modified and improved as a result of the helpful referee`s comments. Now the methods are more detailed than before. The explanation of the experimental design was enhanced, including the insertion of the Scheme 1 (representative of the Experimental Design). The division of the participants in two different groups was better explained and additional details were presented regarding the subjects` characteristics. The lack on literature and our hypothesis were clarified and the results are better discussed now. Furthermore, in regards to the writing style the paper was revised by a native English speaker, an American who is a Professor in languages. Additionally, other parts of the study (general) were enhanced and some additional references were included. For instance, a discussion regarding the limitations of the study was also added on page 11 of the manuscript. The main changes and their locations were presented above over this answer letter.

10.1.3 Carta de aceite

NSOE - JSCR <jscr@uconn.edu> 27 de março de 2008 14:42

Para: rafasotero@gmail.com, Herbert Gustavo Simões <hgsimoes@gmail.com> Dear Prof. Rafael da Costa Sotero and Dr. Herbert Simoes,

75

coauthors in meeting the very high standard of quality that is required for publication in this Journal. You will receive a formal letter of acceptance in the mail. Pending a final format check, all manuscript materials will be forwarded to the production staff at Lippincott, Williams and Wilkins (LWW) for placement in an upcoming issue. LWW will be sending galley proofs and work with you to put your manuscript into format for publication.

I want to take this opportunity to remind you to check the page proofs promptly but carefully for accuracy when you eventually receive them.

Finally, please be aware that there is usually a delay at this point in time of about 9 months before the article will appear in print, due to the high demand for space in the Journal. We are working toward getting this time down to 6 months with LWW. We are adding more journals and pages starting in Jan 2008. So this is just part of the transition to a larger journal and a growing excitement for the JSCR, whose distribution is over 30,000. We will also address the “ahead” of print aspect as well in the near future.

As we continue the process of converting to electronic communication, we hope to move to press more rapidly and cut in-press time down to 5-6 months. We look forward to other manuscripts from your laboratory. Thank you for your patience as the journal continues to grow in impact and high end practical use factors.

Thank you for submitting this study and best wishes for your future work. With Kind Regards,

Amanda Hopkins, BA Staff

Dr. William J. Kraemer Editor-In-Chief

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10.2 Anexo 2 - Polynomial adjustment as a new technique for determination of lactate minimum velocity with reduction blood sampling

10.2.1 Carta de recebimento da submissão

Revista Brasileira de Cineantropometria & Desempenho Humano - ISSN 1415-8426 Brazilian Journal of Kinanthropometry and Human Performance

Universidade Federal de Santa Catarina.

Centro de Desportos – NuCIDH – www.rbcdh.ufsc.br CEP: 88.040-900 – Florianópolis, SC

Tel. (048) 331.9462 R/ 23 Fax. 331.9368

E-MAIL: petroski@cds.ufsc.br nucidh@cds.ufsc.br

Florianópolis, 05 de março de 2007

Prezado Pesquisador: Rafael da Costa Sotero

É com satisfação que comunico o recebimento do artigo científico de vossa autoria:

“POLYNOMIAL ADJUSTMENT AS A NEW APPROACH FOR THE DETERMINATION OF

LACTATE MINIMUM WITH BLOOD SAMPLING REDUCTION". O mesmo foi protocolado

sob o nº 272/2007. O manuscrito será enviado ao Conselho Editorial para ser apreciado com

vista à publicação na RBCDH. Finalmente, em nome do Conselho Editorial agradeço o

envio do mesmo.

Com os melhores cumprimentos,

Andreia Pelegrini Secretaria RBCDH

10.2.2 Carta de aceite

Revista Brasileira de Cineantropometria & Desempenho Humano - ISSN 1415-8426 Brazilian Journal of Kinanthropometry and Human Performance

Universidade Federal de Santa Catarina.

Centro de Desportos – NuCIDH – www.rbcdh.ufsc.br CEP: 88.040-900 – Florianópolis, SC

Tel. (048) 331.9462 R/ 23 Fax. 331.9368

77

Florianópolis, 16 de abril de 2007

Senhores Pesquisadores: Herbert Gustavo Simões / Rafael da Costa Sotero

É com satisfação que comunico que o manuscrito de vossa autoria intitulado “Polynomial adjustment as a new approach for the determination of lactate minimum with blood sampling reduction”, foi aceito para publicação na Revista Brasileira de Cineantropometria & Desempenho Humano n. 9, v. 4, 2007 (ISSN 1415-8426). Finalmente, em nome do Conselho Editorial agradeço o envio do manuscrito.

Com os melhores cumprimentos,

78

10.3 Anexo 3 - Blood glucose minimum predicts maximal lactate steady state on running

10.3.1 Carta de recebimento da submissão

--- Forwarded message --- From: <lehnen@online.de>

Date: 2008/6/26

Subject: International Journal of Sports Medicine - Account Created in Manuscript Central To: rafasotero@gmail.com

26-Jun-2008 Dear Mr. Sotero:

A manuscript titled Maximal lactate steady state predicted by blood glucose (IJSM-06-2008-0923-tt) has been submitted by Dr. Herbert Gustavo Simoes to the International Journal of Sports Medicine.

You are listed as a co-author for this manuscript. The online peer-review system, Manuscript Central, automatically creates a user account for you. Your USER ID and PASSWORD for your account is as follows:

To enter your account, please do the following: Go to: http://mc.manuscriptcentral.com/ijsm

This password is case-sensitive and temporary. Please log in to

http://mc.manuscriptcentral.com/ijsm to update your account information and change your password (under "Edit my Account"). The password should consist of at least eight digits (minimum), two of which must be numbers. You will find in the attached manual a

description how to change your User ID and your password (both should be selected in such a manner that you may find it easy to remember them).

Afterwards you can use the User ID and Password to log in to the site and check the status of papers you have authored/co-authored.

Thank you for your participation. Sincerely,

International Journal of Sports Medicine Editorial Office

10.3.2 Carta resposta (processo de revisão)

79

From: <houmardj@ecu.edu> Date: 2008/8/4

Subject: International Journal of Sports Medicine - Decision on Manuscript ID IJSM-06-2008-0923-tt

To: hgsimoes@gmail.com

8.4.2008

Dear Dr. Simoes:

Manuscript ID IJSM-06-2008-0923-tt entitled "Maximal lactate steady state predicted by blood glucose" which you submitted to the International Journal of Sports Medicine, has been reviewed. The comments of the reviewer(s) are included at the bottom of this letter.

The reviewer(s) have recommended publication, but also suggest some minor revisions to your manuscript. Once the comments and criticisms are addressed sufficiently in your manuscript, it can be considered for publication.

Please do NOT reply to this message; your comments to the editors may be submitted with your revised manuscript. To revise your manuscript, log into http://mc.manuscriptcentral.com/ijsm and enter your Corresponding Author Center, where you will find your manuscript title listed under "Manuscripts with Decisions." Under "Actions," click on "Create a Revision." Your manuscript number has been appended to denote a revision.

Please note: Once you create a revision in the system, your manuscript will subsequently be listed under "Revised Manuscripts in Draft" instead of "Manuscripts with Decisions."

Your original files are available to you when you create your revision in Manuscript Central. Revise your manuscript by downloading the files that you submitted and saving them on your computer. Please make the changes to your manuscript by using the track changes mode in MS Word (In Microsoft Word go to "Tools" –"Track Changes" – "Highlight Changes." Activiate all checkboxes in the "Track Changes" menu.). This highlights your changes so that insertions and deletions of text are visible. Once you have completed the changes you can rename the files and upload them to the system. Please delete any redundant files before completing the submission.

When submitting your revised manuscript, you will be able to respond to the comments made by the reviewer(s) in the space provided. You can use this space to document any changes you make to the original manuscript. In order to expedite the processing of the revised manuscript, please be as specific as possible in your response to the reviewer(s).

Because we are trying to facilitate timely publication of manuscripts submitted to the International Journal of Sports Medicine, your revised manuscript should be uploaded as soon as possible.

80

Sincerely,

Prof. Joseph Houmard

Editor, International Journal of Sports Medicine houmardj@ecu.edu

Editorial Office Comments null

Answers to the comments of Reviewer #1

Dear reviewer #1,

As a result of the reviewer’s helpful comments, the manuscript has been

modified and improved. So some parts of the study were clarified. Furthermore,

the paper was revised (English revision). Overall, we believe the paper is better

now. Below are the main changes as a result of the reviewer’s comments and

their locations in the manuscript.

Comment #1 (General) The present manuscript describes a study investigating correlations and differences between maximal lactate steady state (MLSS), lactate minimum (LM) and glucose minimum (GM) in physically active men. Both LM and GM correlated with MLSS, and no difference among MLSS, LM and GM was found. The study seems to be well conducted; all details have been clearly described and would be a good addition to the body of evidence. However, there are some general and specific points that you ought to address – see below.

Good introduction. It sets out the rationale for the study clearly. However, the hypothesis needs to be sustained in physiological mechanisms. Why the relationship between MLSS and GM obtained during incremental test could be expected? Is there some difference between

trained and untrained subjects?

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Despite the method utilized to identify the anaerobic threshold (e.g lactate threshold, ventilatory threshold, catecholamine threshold, HRV threshold…) there is a close relationship between the anaerobic threshold intensity and the exercise intensity at which blood lactate production equals blood lactate removal (e.g. LM and MLSS). Once the MLSS is defined as an exercise intensity corresponding to this equilibrium point between lactate production and removal, it has been demonstrated that a single incremental test after blood lactate elevation would identify this equilibrium point that was named lactate minimum (Tegtburt et al. 1993). And besides there is no cause-effect relationship between blood glucose threshold (GM) and MLSS, once GM predicts the anaerobic threshold, and this last is associated to the MLSS, the GM would be associated (or would predict) the LM and MLSS too. This hypothesis seemed to be confirmed on present investigation, but for non-athletes. The hypothesis and the possible underlying mechanisms were better pointed out on the manuscript, by the second paragraph of the introduction, with a short explanation (due to space limitations) as follows: The following has been added to the introduction:

“In fact, the potential mechanisms for these similar responses include higher activity of epinephrine and glucagon induced liver glycogenolisys [8, 24] and thus the [bgluc] production to surpass its consumption when exercise intensity associated to [lac] accumulation is reached (e.g. above LM).” (Page 2, lines 16 to 17 from introduction)

Comment #2 (Specific – Abstract) The main results (e.g., running speeds at MLSS, LM and GM, correlations and level of agreement) must be shown.

Response to Comment #2: The abstract was re-written to include the main results.

“…Repeated measures ANOVA showed no differences between running speeds associated to the GM (205.2±15.7 m.min-1), LM (203.8±16.3 m.min-1) and MLSS (205.7±13.9 m.min-1), with high correlation between GM vs LM (r=0.968), GM vs MLSS (r=0.833) and LM vs MLSS (r=0.876). The Bland and Altman plots evidenced an agreement [Bias (±95% CI)] for GM and MLSS [-0.2 (14.7) m.min-1], MLSS and LM [-1.5 (14.8) m.min-1], as well as for LM and GM [1.3 (7.7) m.min-1]..…” (Page 1, lines 7 to 12 from Abstract)

Comment #3 (Methods) How the running speeds corresponding to the lowest [lac] and [bgluc] were determined? Was it used visual inspection or the data were adjusted by some function (e.g., cubic spline)?Was the nutritional status controlled? If not, is there some methodological limitations?

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status, that was a concern of both referees, is better described on methods section too (see 4th paragraph of page 4).

Comment #4 (Figures) Figure 2 – Please change MEEL by MLSS.

Response to Comment #4: The figures were changed properly. See below and also on page 15, from List of Figures

Comment #5 The English needs to be revised. The paper can not be printed as it stands.

Response to Comment #5: We have addressed the English grammar within this manuscript.

Answers to the comments of Reviewer #2

83

As a result of the reviewer’s helpful comments, the manuscript has been modified and improved. So some parts of the study were clarified. Furthermore, the paper was revised (English revision). Overall, we believe the paper is better now. Below are the main changes as a result of the reviewer’s comments and their locations in the manuscript.

Comments to the Author (reviewer #2)

The paper examines the possibility of maximal lactate steady state estimation using blood glucose responses during incremental running test, with prior sprinting. The authors have shown that glucose minimum velocity was similar to maximal lactate steady state, and that the agreement between these measures was acceptable for practical using.

It is well constructed, with appropriate length to be published.

Comment #1 (Introduction)

The authors should state the rationale of the study. Why using blood glucose is advantageous in comparison to blood lactate? How do the coaches and practioners can benefit of this method?

Response to Comment #1: We included one sentence in the beginning of the last paragraph of introduction (page 3) to address these points, as follows:

“The analyses of the [bgluc] responses would be of practical consideration, especially as a cost saving, reducing overall supplies needed, and also to increase the accuracy of MLSS prediction when [bgluc] measures are done at the same time as [lac] [18,19].” (Page 2, lines 18 to 20 from Introduction)

Comment #2 (Methods)

Were there special recommendations regarding the last meal and hydration state prior to the tests? It seems to me that this aspect is crucial to the protocol, as the blood glucose regulation would be disturbed during exercise under hypoglycaemia, for example. The authors should address this issue in the paper.

Response to Comment #2: The referee’s concern is important. So we clarified the Methods section with information regarding our recommendations to the participants as follows: “For all sessions the participants were instructed to eat the last meal two hours before testing and to keep hydrated. In addition, the ingestion of alcoholic beverages and the practice of intense exercise were not allowed during the last twenty four hours before testing.” (Page 3, lines 19 to 21 from Methods)

Comment #3 (Discussion)

The authors argue that sympathetic activity induces hepatic glycogenolysis for the

84

Are the autonomic and hormonal responses induced by the adopted protocol also responsible for the lactate minumum occurance? If so, it can be highlighted by the authors, as it would reinforce the physiological link between these two metabolic thresholds.

Response to Comment #3: This comment is similar to the comment #1 of the referee #1. Therefore, please see the answer to the referee #1 too. In general, we tried to address this concern in both Introduction and Discussion section. For the introduction we included the following sentence:

“In fact, the potential mechanisms for these similar responses include higher activity of epinephrine and glucagon induced liver glycogenolisys [8,24] and thus the [bgluc] production to surpass its consumption when exercise intensity associated to [lac] accumulation is reached (e.g. above LM)” (Page 2, lines 16 to 17 from introduction)

The sympathetic nervous system (SNS) activity and the increased levels of glucagon induced [bgluc] to increase may be linked mainly to the occurrence of the GM. In spite of the

increased SNS activity be associated both to the higher glycolisys and lactate production, we don’t know to which magnitude the SNS activity contributes to the blood lactate accumulation observed during the ascendant part of the U-shaped curve. So the discussion section was reorganized a little to present such mechanisms (increase in the glucagon and

epinephrine/SNS activity) as a possible explanation of the [bgluc] responses. We avoided extending these mechanisms as linked to the [lac] but to maintain the focuses on [bgluc] responses. Below there are some changes we did in Discussion section (2nd paragraph of page 7) as a result of referee’s comment:.

“Previous studies involving endurance runners have proposed that after reaching the anaerobic threshold during an incremental test there is an increase in the activity of hyperglycemiant hormones such as glucagon and catecholamines. It therefore is possible that the liver glycogenolysis induced by these hormones [8, 24] helps to explain the [bgluc] production surpassing its consumption by skeletal muscles, leading the [bgluc] to increase when exercise intensity above LM is reached [18,20]. It is likely this point that enables the identification of the brake even point of aerobic-anaerobic balance during exercise as previously suggested [13, 17, 18, 19, 21, 23]. In this study, kinetics of [bgluc] responded similarly to [lac] as an "U" shaped curve during the incremental test after blood lactate elevation, allowing to determine the GM for non-athletes too (Figure 1).

Comments #4-9 (Specific comments)

Pg2 line 27 - "...from a single test session has been the focus of several research", not focuses Response – OK. It has been corrected (Page 2, line 7 from Introduction)

Pg3 line 45 - "...a [la] variation did not surpass...", not didn't

Response – OK. It has been corrected (Page 3, line 16 from Methods) Pg3 line 48 - "as described previously [2,3,16,24]"