Efeito da ingestão de cafeína sobre os parâmetros da potência crítica

Machado, Marcus Vinícius; Batista, Alexandre Rosas; Altimari, Leandro Ricardo; Fontes, Eduardo Bodnariuc; Triana, Ricardo Okada; Okano, Alexandre Hideki; Marques, Alessandro Custódio; Andries Júnior, Orival; Moraes, Antonio Carlos de

doi:10.5007/1980-0037.2010v12n1p49

Resumos

O objetivo do presente estudo foi verificar o efeito da ingestão de cafeína sobre os parâmetros do modelo de potência crítica determinado em cicloergômetro. Participaram do estudo oito sujeitos do sexo masculino. A ingestão de cafeína pura (6 mg.kg-1) ou placebo (maltodextrina) foi realizada através de protocolo duplo-cego, 60 minutos antes dos testes. Para determinação da potência crítica, os sujeitos foram submetidos a quatro testes de cargas constantes em cicloergômetro, realizados aleatoriamente, nos momentos cafeína e placebo, nas intensidades de 80, 90, 100 e 110% da potência máxima, a uma cadência de 70 rpm até a exaustão. A potência crítica e a capacidade de trabalho anaeróbio foram obtidas através de regressão não linear e ajuste de curva para o modelo hiperbólico potência-tempo. Para o tratamento estatístico, utilizaram-se-se o teste de Shapiro Wilk e o teste t de Student pareado. Não foram encontradas diferenças significativas na potência crítica nas condições cafeína e placebo (192,9 ± 31,3 vs 197,7 ± 29,4 W, respectivamente). A capacidade de trabalho anaeróbio foi significativamente maior na condição cafeína (20,1 ± 5,2 vs 16,3 ± 4,2 W, p< 0,01). Foi, ainda, obtido um alto valor de associação (r²) entre as condições cafeína e placebo (0,98± 0,02 e 0,99± 0,0). Através dos resultados obtidos, concluiu-se que a ingestão de cafeína não proporcionou melhorias no desempenho da potência crítica, entretanto, elevou os valores da capacidade de trabalho anaeróbio por influenciar o desempenho nas cargas de maior intensidade e menor duração.

Potência Crítica; Cafeína; Ergogênico

The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg) or placebo (maltodextrin) 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively). The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p<0.01). A high association (r²) was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively). We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

Critical power; Caffeine; Ergogenic; Ergogenic supplement

ARTIGO ORIGINAL

Efeito da ingestão de cafeína sobre os parâmetros da potência crítica

Effect of caffeine intake on critical power model parameters determined on a cycle ergometer

Marcus Vinícius Machado^I;II;III; Alexandre Rosas Batista^I;III; Leandro Ricardo Altimari^I;III;IV; Eduardo Bodnariuc Fontes^I;III;IV; Ricardo Okada Triana^I;III; Alexandre Hideki Okano^III;IV;V; Alessandro Custódio Marques^I;II; Orival Andries Júnior^I;II; Antonio Carlos de Moraes^I;III

^IUniversidade Estadual de Campinas. Faculdade de Educação Física. Programa de Pós-Graduação em Educação Física. Campinas, SP. Brasil.

^IIUniversidade Estadual de Campinas. Faculdade de Educação Física. Laboratório de Atividades Aquáticas. Campinas, SP. Brasil.

^IIIUniversidade Estadual de Campinas. Faculdade de Educação Física. Grupo de Estudo e Pesquisa em Sistema Neuromuscular. Campinas, SP. Brasil.

^IVUniversidade Estadual de Londrina. Centro de Educação Física e Desporto. Grupo de Estudo e Pesquisa em Metabolismo, Nutrição e Exercício. Londrina, PR. Brasil.

^VUniversidade Federal do Rio Grande do Norte. Departamento de Educação Física. Grupo de Estudo e Pesquisa em Biologia Integrativa do Exercício. Natal, RN. Brasil.

^{Correspondencia para} Marcus Vinicius Machado Instituto Oswaldo Cruz Laboratório de Investigação Cardiovascular Av. Brasil, 4365, Manguinhos. CEP 21045-900 Rio de Janeiro, RJ. Brasil. E-mail: marcus_machado@globomail.com

RESUMO

O objetivo do presente estudo foi verificar o efeito da ingestão de cafeína sobre os parâmetros do modelo de potência crítica determinado em cicloergômetro. Participaram do estudo oito sujeitos do sexo masculino. A ingestão de cafeína pura (6 mg.kg^-1) ou placebo (maltodextrina) foi realizada através de protocolo duplo-cego, 60 minutos antes dos testes. Para determinação da potência crítica, os sujeitos foram submetidos a quatro testes de cargas constantes em cicloergômetro, realizados aleatoriamente, nos momentos cafeína e placebo, nas intensidades de 80, 90, 100 e 110% da potência máxima, a uma cadência de 70 rpm até a exaustão. A potência crítica e a capacidade de trabalho anaeróbio foram obtidas através de regressão não linear e ajuste de curva para o modelo hiperbólico potência-tempo. Para o tratamento estatístico, utilizaram-se-se o teste de Shapiro Wilk e o teste t de Student pareado. Não foram encontradas diferenças significativas na potência crítica nas condições cafeína e placebo (192,9 ± 31,3 vs 197,7 ± 29,4 W, respectivamente). A capacidade de trabalho anaeróbio foi significativamente maior na condição cafeína (20,1 ± 5,2 vs 16,3 ± 4,2 W, p< 0,01). Foi, ainda, obtido um alto valor de associação (r²) entre as condições cafeína e placebo (0,98± 0,02 e 0,99± 0,0). Através dos resultados obtidos, concluiu-se que a ingestão de cafeína não proporcionou melhorias no desempenho da potência crítica, entretanto, elevou os valores da capacidade de trabalho anaeróbio por influenciar o desempenho nas cargas de maior intensidade e menor duração.

Palavras-chave: Potência Crítica; Cafeína; Ergogênico

ABSTRACT

The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg) or placebo (maltodextrin) 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively). The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p<0.01). A high association (r²) was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively). We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

Keywords: Critical power; Caffeine; Ergogenic; Ergogenic supplement

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Recebido em 04/06/08

Revisado em 26/01/09

Aprovado em 18/05/09

1. Davis JM, Zhao Z, Stock HS, Mehl KA, Buggy J, Hand GA. Central nervous system effects of caffeine and adenosine on fatigue. Am J Physiol 2003; 284 (Suppl):R399-R404.
2. Graham TE. Caffeine and exercise: metabolism, endurance and performance. Sports Med 2001;31(11):785-807.
3. Lindinger MI, Graham TE, Spriet LL. Caffeine attenuates the exercise-induced increases in plasma [K⁺] in humans, J Appl Physiol 1993;74(3):1149-1155.
4. Tarnopolsky MA, Cupido C. Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine users. J Appl Physiol 2000;89(5):1719-1724.
5. Graham TE, Rush JW, Van Soeren MH. Caffeine and exercise: metabolism and performance. Can J Appl Physiol 1994;19(2):111-138.
6. Greer F, Friars D, Graham TE. Comparison of caffeine and theophylline ingestion: exercise metabolism and endurance. J Appl Physiol 2000;89(5):1837-1844.
7. Bruce CR, Anderson ME, Fraser SF, Stepto NK, Klein R, Hopkins WG, et al. Enhancement of 2000-m rowing performance after caffeine ingestion. Med Sci Sports Exerc 2000; 32(11):1958-1963.
8. Doherty M, Smith PM, Hughes MG, Davison RC. Caffeine lowers percentual response and increases power output during high-intensity cycling. J Sports Sci 2004;22(7):637-643.
9. Jackman M, Wendling P, Friars D, Graham TE. Metabolic, catecholamine and endurance responses to caffeine during intense exercise. J Appl Physiol 1996;81(4):1658-1663.
10. Spriet LL. Caffeine and performance. Int J Sports Nutr 1995;5(Suppl):S84-S99.
11. Kalmar JM, Caffarelli E. Caffeine: a valuable tool to study central fatigue in humans? Exerc Sport Sci Rev 2004;32(4):143-147.
12. Monod H, Sherrer J. The work capacity of a synergic muscular group. Ergonomics 1965;8(3):329-338.
13. Wakayoshi K, Ilkuta K, Yoshida T. Determination and validity of critical velocity speed as an index of swimming performance in the competitive swimmer. Eur J Appl Physiol Occup Physiol 1992;64(2):153-157.
14. Wakayoshi K, Yoshida T, Udo M, Harada T, Moritani T, Mutoh Y, et al. Does critical swimming velocity represent exercise intensity at maximal lactate steady state? Eur J Appl Physiol Occup Physiol 1993;66(1):90-95.
15. Moritani T, Nagata A, Devries H, Muro M. Critical power as a measure of physical work capacity and anaerobic threshold. Ergonomics 1981;24(5):339-350.
16. Le Chevalier JM, Vandewalle H, Thépaut-Mathieu C, Stein JF, Caplan L. Local critical power is an index of local endurance. Eur J Appl Physiol 2000;81(1-2):120-127.
17. Hill DW, Smith JC. A method to ensure the accuracy of estimates of anaerobic capacity derived using the critical power concept. J Sports Med Phys Fitness 1994;34(1):23-37.
18. Calis JF, Denadai BS. Influência das cargas selecionadas na determinação da potência crítica determinada no ergômetro de braço em dois modelos lineares. Rev Bras Med Esporte 2000;6(1):1-4.
19. Housh DJ, Housh TJ, Bauge SM. A methodological consideration for the determination of critical power and anaerobic work capacity. Res Quarterly Exerc Sport 1990;61(4):406-409.
20. Miura A, Sato H, Whipp BJ, Fukuba Y. The effect of glycogen depletion on the curvature constant parameter of the power-duration curve for cycle ergometry, Ergonomics 2000; 46(1):133-141.
21. Smith JC, Stephens DP, Hall EL, Jackson AW, Earnest CP. Effect of oral creatine ingestion on parameters of work-time relationship and time to exhaustion in high-intensity cycling. Eur J Appl Physiol 1998;77(4):360-365.
22. Eckerson JM, Stout JR, Moore GA, Stone NJ, Nishimura K, Tamura K. Effect of two and five days of creatine loading on anaerobic working capacity in women. J Strength Condit Res 2004;18(1):168-173.
23. Jenkins DG, Quigley BM. Endurance training enhances critical power. Med Sci Sports Exerc 1992;24(11):1283-1289.
24. Jenkins DG, Quigley BM. The influence of high-intensity exercise training on the Wlin-Tlim relationship. Med Sci Sports Exerc 1993;25(2):275-282.
25. Anselme F, Collomp K, Mercier B, Ahmaidi S, Prefaut C. Caffeine increases maximal anaerobic power and blood lactate concentration. Eur J Appl Physiol 1992;65(2):188-191.
26. Paton CD, Hopkins WG, Volebregt L. Little effect of caffeine ingestion on repeated sprints in team-sport athletes. Med Sci Sports Exerc 2001;33(5):822-825.
27. Jackman M, Wendling A, Friars D, Graham TE. Metabolic, catecholamine, and endurance responses to caffeine during intense exercise. J Appl Physiol1996;81(4):1658-1663.
28. Doherty M. The effects of caffeine on the maximal accumulated oxygen deficit and short-term running performance. Int J Sports Nutr 1998;8(2):95-104.
29. Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33(11):1399-1403.
30. Alves MN, Ferrari-Auarek WM, Pinto KMC, Sá KR, Viveiros JP, Pereira HAA, et al. Effects of caffeine on tryptophan on rectal temperature, metabolism, total exercise time, rate of perceived exertion and heart rate. Braz J Med Biol Res 1995;28(6):705-709.
31. Butts NK, Crowell D. Effect of caffeine ingestion on cardiorespiratory endurance in men and women. Res Q Exerc Sport 1985;56(4):301-305.

Marcus Vinicius Machado

Instituto Oswaldo Cruz

Laboratório de Investigação Cardiovascular

Av. Brasil, 4365, Manguinhos.

CEP 21045-900 Rio de Janeiro, RJ. Brasil.

E-mail:

marcus_machado@globomail.com

Datas de Publicação

Publicação nesta coleção
06 Fev 2013
Data do Fascículo
Fev 2010

Histórico

Revisado
26 Jan 2009
Recebido
04 Jun 2008
Aceito
18 Maio 2009

This work is licensed under a Creative Commons Attribution 4.0 International License.

[1] 1. Davis JM, Zhao Z, Stock HS, Mehl KA, Buggy J, Hand GA. Central nervous system effects of caffeine and adenosine on fatigue. Am J Physiol 2003; 284 (Suppl):R399-R404.

[2] 2. Graham TE. Caffeine and exercise: metabolism, endurance and performance. Sports Med 2001;31(11):785-807.

[3] 3. Lindinger MI, Graham TE, Spriet LL. Caffeine attenuates the exercise-induced increases in plasma [K⁺] in humans, J Appl Physiol 1993;74(3):1149-1155.

[4] 4. Tarnopolsky MA, Cupido C. Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine users. J Appl Physiol 2000;89(5):1719-1724.

[5] 5. Graham TE, Rush JW, Van Soeren MH. Caffeine and exercise: metabolism and performance. Can J Appl Physiol 1994;19(2):111-138.

[6] 6. Greer F, Friars D, Graham TE. Comparison of caffeine and theophylline ingestion: exercise metabolism and endurance. J Appl Physiol 2000;89(5):1837-1844.

[7] 7. Bruce CR, Anderson ME, Fraser SF, Stepto NK, Klein R, Hopkins WG, et al. Enhancement of 2000-m rowing performance after caffeine ingestion. Med Sci Sports Exerc 2000; 32(11):1958-1963.

[8] 8. Doherty M, Smith PM, Hughes MG, Davison RC. Caffeine lowers percentual response and increases power output during high-intensity cycling. J Sports Sci 2004;22(7):637-643.

[9] 9. Jackman M, Wendling P, Friars D, Graham TE. Metabolic, catecholamine and endurance responses to caffeine during intense exercise. J Appl Physiol 1996;81(4):1658-1663.

[10] 10. Spriet LL. Caffeine and performance. Int J Sports Nutr 1995;5(Suppl):S84-S99.

[11] 11. Kalmar JM, Caffarelli E. Caffeine: a valuable tool to study central fatigue in humans? Exerc Sport Sci Rev 2004;32(4):143-147.

[12] 12. Monod H, Sherrer J. The work capacity of a synergic muscular group. Ergonomics 1965;8(3):329-338.

[13] 13. Wakayoshi K, Ilkuta K, Yoshida T. Determination and validity of critical velocity speed as an index of swimming performance in the competitive swimmer. Eur J Appl Physiol Occup Physiol 1992;64(2):153-157.

[14] 14. Wakayoshi K, Yoshida T, Udo M, Harada T, Moritani T, Mutoh Y, et al. Does critical swimming velocity represent exercise intensity at maximal lactate steady state? Eur J Appl Physiol Occup Physiol 1993;66(1):90-95.

[15] 15. Moritani T, Nagata A, Devries H, Muro M. Critical power as a measure of physical work capacity and anaerobic threshold. Ergonomics 1981;24(5):339-350.

[16] 16. Le Chevalier JM, Vandewalle H, Thépaut-Mathieu C, Stein JF, Caplan L. Local critical power is an index of local endurance. Eur J Appl Physiol 2000;81(1-2):120-127.

[17] 17. Hill DW, Smith JC. A method to ensure the accuracy of estimates of anaerobic capacity derived using the critical power concept. J Sports Med Phys Fitness 1994;34(1):23-37.

[18] 18. Calis JF, Denadai BS. Influência das cargas selecionadas na determinação da potência crítica determinada no ergômetro de braço em dois modelos lineares. Rev Bras Med Esporte 2000;6(1):1-4.

[19] 19. Housh DJ, Housh TJ, Bauge SM. A methodological consideration for the determination of critical power and anaerobic work capacity. Res Quarterly Exerc Sport 1990;61(4):406-409.

[20] 20. Miura A, Sato H, Whipp BJ, Fukuba Y. The effect of glycogen depletion on the curvature constant parameter of the power-duration curve for cycle ergometry, Ergonomics 2000; 46(1):133-141.

[21] 21. Smith JC, Stephens DP, Hall EL, Jackson AW, Earnest CP. Effect of oral creatine ingestion on parameters of work-time relationship and time to exhaustion in high-intensity cycling. Eur J Appl Physiol 1998;77(4):360-365.

[22] 22. Eckerson JM, Stout JR, Moore GA, Stone NJ, Nishimura K, Tamura K. Effect of two and five days of creatine loading on anaerobic working capacity in women. J Strength Condit Res 2004;18(1):168-173.

[23] 23. Jenkins DG, Quigley BM. Endurance training enhances critical power. Med Sci Sports Exerc 1992;24(11):1283-1289.

[24] 24. Jenkins DG, Quigley BM. The influence of high-intensity exercise training on the Wlin-Tlim relationship. Med Sci Sports Exerc 1993;25(2):275-282.

[25] 25. Anselme F, Collomp K, Mercier B, Ahmaidi S, Prefaut C. Caffeine increases maximal anaerobic power and blood lactate concentration. Eur J Appl Physiol 1992;65(2):188-191.

[26] 26. Paton CD, Hopkins WG, Volebregt L. Little effect of caffeine ingestion on repeated sprints in team-sport athletes. Med Sci Sports Exerc 2001;33(5):822-825.

[27] 27. Jackman M, Wendling A, Friars D, Graham TE. Metabolic, catecholamine, and endurance responses to caffeine during intense exercise. J Appl Physiol1996;81(4):1658-1663.

[28] 28. Doherty M. The effects of caffeine on the maximal accumulated oxygen deficit and short-term running performance. Int J Sports Nutr 1998;8(2):95-104.

[29] 29. Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33(11):1399-1403.

[30] 30. Alves MN, Ferrari-Auarek WM, Pinto KMC, Sá KR, Viveiros JP, Pereira HAA, et al. Effects of caffeine on tryptophan on rectal temperature, metabolism, total exercise time, rate of perceived exertion and heart rate. Braz J Med Biol Res 1995;28(6):705-709.

[31] 31. Butts NK, Crowell D. Effect of caffeine ingestion on cardiorespiratory endurance in men and women. Res Q Exerc Sport 1985;56(4):301-305.