VO(2) kinetics in heavy exercise is not altered by prior exercise with a different muscle group.
J Appl Physiol (1985)
; 92(6): 2467-74, 2002 Jun.
Article
em En
| MEDLINE
| ID: mdl-12015361
ABSTRACT
We examined whether lactic acidemia-induced hyperemia at the onset of high-intensity leg exercise contributed to the speeding of pulmonary O(2) uptake (VO(2)) after prior heavy exercise of the same muscle group or a different muscle group (i.e., arm). Six healthy male subjects performed two protocols that consisted of two consecutive 6-min exercise bouts separated by a 6-min baseline at 0 W 1) both bouts of heavy (work rate 50% of lactate threshold to maximal VO(2)) leg cycling (L1-ex to L2-ex) and 2) heavy arm cranking followed by identical heavy leg cycling bout (A1-ex to A2-ex). Blood lactate concentrations before L1-ex, L2-ex, and A2-ex averaged 1.7 +/- 0.3, 5.6 +/- 0.9, and 6.7 +/- 1.4 meq/l, respectively. An "effective" time constant (tau) of VO(2) with the use of the monoexponential model in L2-ex (tau 36.8 +/- 4.3 s) was significantly faster than that in L1-ex (tau 52.3 +/- 8.2 s). Warm-up arm cranking did not facilitate the VO(2) kinetics for the following A2-ex [tau 51.7 +/- 9.7 s]. The double-exponential model revealed no significant change of primary tau (phase II) VO(2) kinetics. Instead, the speeding seen in the effective tau during L2-ex was mainly due to a reduction of the VO(2) slow component. Near-infrared spectroscopy indicated that the degree of hyperemia in working leg muscles was significantly higher at the onset of L2-ex than A2-ex. In conclusion, facilitation of VO(2) kinetics during heavy exercise preceded by an intense warm-up exercise was caused principally by a reduction in the slow component, and it appears unlikely that this could be ascribed exclusively to systemic lactic acidosis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Consumo de Oxigênio
/
Resistência Física
/
Braço
/
Exercício Físico
/
Músculo Esquelético
/
Perna (Membro)
Tipo de estudo:
Etiology_studies
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
J Appl Physiol (1985)
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Japão