RESUMO
Exercise promotes pulmonary oxidative imbalance. In this regard, some evidence has been obtained from the study of exhaled breath condensate (EBC) during urban races, in which the factors involved in the occurrence of this process are still not characterized. In this paper, under laboratory conditions, both the role of time of exercise on the generation of pro-oxidants (H2O2, NO2 (-)) and pH have been assessed in EBC of 16 under-trained subjects who completed three tests of cycloergometric exercise at low intensity (30 % of VO2 max) with a duration of 10, 30, and 90 min. Samples were obtained as follows: immediately before and at 80 min post exertion in each test. In the 90-min test, an increase in H2O2, NO2 (-) concentration in EBC at 80 min post exertion with no changes in the pH was observed. Total O2 consumption and total ventilation weakly correlated with the changes in H2O2 and NO2 (-). In conclusion, the concentration of pro-oxidants in the EBC depends on the duration of the exercise when it is performed at low intensity under laboratory conditions.
Assuntos
Exercício Físico , Pulmão/metabolismo , Oxidantes/metabolismo , Mucosa Respiratória/metabolismo , Adolescente , Adulto , Ciclismo , Testes Respiratórios , Teste de Esforço , Frequência Cardíaca , Humanos , Peróxido de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Masculino , Nitritos/metabolismo , Consumo de Oxigênio , Eliminação Pulmonar , Taxa Respiratória , Fatores de Tempo , Adulto JovemRESUMO
BACKGROUND: The innervation zone (IZ) corresponds to the location of the neuromuscular junctions. Its location can be determined by using arranged surface linear electrode arrays. Typically, voluntary muscle contractions (VC) are used in this method. However, it also may be necessary to locate the IZ under clinical conditions such as spasticity, in which this type of contraction is difficult to perform. Therefore, contractions imposed by electrostimulation (ES) can be an alternative. There is little background comparing the locations of IZ obtained by two different types of contractions. OBJECTIVE: Evaluate the concordance between using voluntary and imposed contractions from electrostimulation in order to determine the location of the innervation zone of the tibialis anterior muscle in healthy volunteers. METHODS: The tibialis anterior (TA) muscle of sixteen volunteers (men: 8; women: 8; age: 22.1±1.4years, weight: 61.6±7.5kg, height: 167.1±7.5cm) were evaluated using a linear electrode array. The IZ of the TA muscle was located using two types of muscle contractions, voluntary (10% MVC) and imposed contractions by ES. The concordance between both conditions was evaluated using the Bland-Altman method and the concordance correlation coefficient (CCC). The analyses were applied to the absolute and relative positions to the length of an anatomical landmark frame. RESULTS: CCC for absolute position was 0.98 (p<0.0001, 95% CI [0.98-1.00], and CCC for relative positions also was 0.98 (p<0.0001, 95% CI [0.97-1.00]). The Bland-Altman analysis for absolute data showed an average difference of -0.63mm (SD: 4.1). Whereas, for adjusted data, the average difference was -0.20% (SD: 1.2). The power of the results, based on absolute data, was 98%, whereas for relative data, 82%. CONCLUSION: In healthy volunteers, there was a substantially concordance between the location of the IZ of the TA muscle derived from using contractions imposed by ES and the location derived from using VC.