Comparação das intensidades correspondentes ao lactato mínimo, limiar de lactato e limiar anaeróbio durante o ciclismo em atletas de endurance
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Data
2000-10-01
Autores
Lucas, Ricardo Dantas de [UNESP]
Rocha, Renato [UNESP]
Burini, Roberto Carlos [UNESP]
Denadai, Benedito Sérgio [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Medicina do Exercício e do Esporte
Resumo
O objetivo deste estudo foi comparar a intensidade de exercício no lactato mínimo (LACmin), com a intensidade correspondente ao limiar de lactato (LL) e limiar anaeróbio (LAn). Participaram do estudo, 11 atletas do sexo masculino (idade, 22,5 + 3,17 anos; altura, 172,3 + 8,2 cm; peso, 66,9 + 8,2kg; e gordura corporal, 9,8 + 3,4%). Os indivíduos foram submetidos, em uma bicicleta eletromagnética (Quinton - Corival 400), a dois testes: 1) exercício contínuo de cargas crescentes - carga inicial de 100W, com incrementos de 25W a cada três min. até a exaustão voluntária; e 2) teste de lactato mínimo - inicialmente os indivíduos pedalaram duas vezes 425W (+ 120%max) durante 30 segundos, com um min. de intervalo, com o objetivo de induzir o acúmulo de lactato. Após oito min. de recuperação passiva, os indivíduos iniciaram um teste contínuo de cargas progressivas, idêntico ao descrito anteriormente. O LL e o LAn foram identificados como sendo o menor valor entre a razão - lactato sanguíneo (mM) / intensidade de exercício (W), e a intensidade correspondente a 3,5mM de lactato sanguíneo, respectivamente. O LACmin foi identificado como sendo a intensidade correspondente a menor concentração de lactato durante o teste de cargas progressivas. Não foi observada diferença significante entre a potência do LL (197,7 + 20,7W) e do LACmin (201,6 + 13,0W), sendo ambas significantemente menores do que do LAn (256,7 + 33,3W). Não foram encontradas também diferenças significantes para o (ml.kg-1.min-1) e a FC (bpm) obtidos no LL (43,2 + 5,01; 152,0 + 13,0) e no LACmin (42,1 + 3,9; 159,0 + 10,0), sendo entretanto significantemente menores do que os obtidos para o LAn (52,2 + 8,2; 174,0 + 13,0, respectivamente). Pode-se concluir que o teste de LACmin, nas condições experimentais deste estudo, pode subestimar a intensidade de MSSLAC (estimada indiretamente pelo LAn), o que concordacom outros estudos que determinaram a MSSLAC diretamente. Assim, são necessários mais estudos que analisem o possível componente tempo-dependente (intensidade inicial) que pode existir no protocolo do LACmin.
The objective of this study was to compare the exercise intensity at lactate minimum (LACmin), with the intensity corresponding to lactate threshold (LT) and anaerobic threshold (AT). Eleven male athletes (age, 22.5 + 3.17 yr.; height, 172.3 + 8.2 cm; weight, 66.9 + 8.2 kg; and body fat, 9.8 + 3.4 %), participated in this study. The individuals performed two tests in an electromagnetic cycle (Quinton - Corival 400): 1) progressive load test - initial load of 100 W, with increments of 25 W to volitional fatigue; and 2) lactate minimum test - initially the individuals performed two supramaximal boats (+ 120% max) for 30 seconds, with 1-min. rest interval between boats to induce hyperlactemia. After 8 min. of passive recovery, individuals began a progressive load test, identical to that previously described. LT and AT were identified as the smallest values among the ratio - blood lactate (mM) : exercise intensity (W), and the intensity corresponding to 3.5 mM of blood lactate, respectively. The LACmin intensity (the intensity corresponding to the nadir on the blood lactate versus intensity plot) was determined from the zero gradient tangent to a spline function fitting the blood lactate data derived from the incremental part of the test. No significant difference was observed among the power at the LT (197.7 + 20.7 W) and LACmin (201.6 + 13.0 W), being both significantly lower than AT (256.7 + 33.3 W). There were no significant differences for the (ml.kg-1.min-1) and HR (bpm) obtained at the LT (43.2 + 5.01; 152.0 + 13.0) and LACmin (42.1 + 3.9; 159.0 + 10.0), being however significantly lower than that obtained at the AT (52.2 + 8.2; 174.0 + 13.0, respectively). It can be concluded that the LACmin test, under the condition of this investigation, can underestimate the intensity of MSSLAC (indirectly assessed by AT), which is consistent with other studies that determined MSSLAC directly. Thus, more studies are necessary to access the possible time-dependant component (initial intensity) that may exist in the LACmin test.
The objective of this study was to compare the exercise intensity at lactate minimum (LACmin), with the intensity corresponding to lactate threshold (LT) and anaerobic threshold (AT). Eleven male athletes (age, 22.5 + 3.17 yr.; height, 172.3 + 8.2 cm; weight, 66.9 + 8.2 kg; and body fat, 9.8 + 3.4 %), participated in this study. The individuals performed two tests in an electromagnetic cycle (Quinton - Corival 400): 1) progressive load test - initial load of 100 W, with increments of 25 W to volitional fatigue; and 2) lactate minimum test - initially the individuals performed two supramaximal boats (+ 120% max) for 30 seconds, with 1-min. rest interval between boats to induce hyperlactemia. After 8 min. of passive recovery, individuals began a progressive load test, identical to that previously described. LT and AT were identified as the smallest values among the ratio - blood lactate (mM) : exercise intensity (W), and the intensity corresponding to 3.5 mM of blood lactate, respectively. The LACmin intensity (the intensity corresponding to the nadir on the blood lactate versus intensity plot) was determined from the zero gradient tangent to a spline function fitting the blood lactate data derived from the incremental part of the test. No significant difference was observed among the power at the LT (197.7 + 20.7 W) and LACmin (201.6 + 13.0 W), being both significantly lower than AT (256.7 + 33.3 W). There were no significant differences for the (ml.kg-1.min-1) and HR (bpm) obtained at the LT (43.2 + 5.01; 152.0 + 13.0) and LACmin (42.1 + 3.9; 159.0 + 10.0), being however significantly lower than that obtained at the AT (52.2 + 8.2; 174.0 + 13.0, respectively). It can be concluded that the LACmin test, under the condition of this investigation, can underestimate the intensity of MSSLAC (indirectly assessed by AT), which is consistent with other studies that determined MSSLAC directly. Thus, more studies are necessary to access the possible time-dependant component (initial intensity) that may exist in the LACmin test.
Descrição
Palavras-chave
Lactato mínimo, Limiar de lactato, Limiar anaeróbio, Ciclismo, Lactate minimum, Lactate threshold, Anaerobic threshold, Cycling
Como citar
Revista Brasileira de Medicina do Esporte. Sociedade Brasileira de Medicina do Exercício e do Esporte, v. 6, n. 5, p. 172-179, 2000.