RESUMO
NEW FINDINGS: What is the central question of this study? What is the reliability of near-infrared spectroscopy-derived muscle oxygen uptake ( mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ ) kinetics following running exercise and what is the relationship between the time constant of mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ off-kinetics and parameters of aerobic fitness? What is the main finding and its importance? The time constant of mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ kinetics in gastrocnemius following moderate running exercise presents good to excellent reliability. In addition, it was well correlated with parameters of aerobic fitness, such as maximal speed of an incremental test, ventilatory threshold and pulmonary VÌO2${\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ on-kinetics. Therefore, near-infrared spectroscopy-derived muscle oxidative capacity together with other physiological measurements may allow a concomitant local and systemic analysis of the components of the oxidative system. ABSTRACT: Near-infrared spectroscopy-derived muscle oxygen uptake ( mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ ) kinetics following single-joint exercise has been used to assess muscle oxidative capacity. However, little evidence is available on the use of this technique following whole-body exercise. Therefore, this study aimed to assess the reliability of the NIRS-derived mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ kinetics following running exercise and to investigate the relationship between the time constant of mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ off-kinetics ( τmVÌO2$\tau {\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ ) and parameters of aerobic fitness. After an incremental test to determine VÌO2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ , first (VT1 ) and second (VT2 ) ventilatory thresholds, and maximal speed (Smax ), 13 males (age = 21 ± 4 years; VÌO2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ = 55.9 ± 3.4 ml kg-1 min-1 ) performed three sets (two on the first day and one on a subsequent day) of two repetitions of 6-min running exercise at 90%VT1 . The pulmonary VÌO2${\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ ( pVÌO2${\rm{p}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ ) on-kinetics and mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ off-kinetics in gastrocnemius were assessed. τmVÌO2$\tau {\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ presented no systematic change and satisfactory reliability (the standard error of the measurement (SEM) and intraclass correlation coefficient of 4.21 s and 0.49 for between transitions; and 2.65 s and 0.74 averaging τmVÌO2$\tau {\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ within each time set), with no difference (P > 0.3) between the within- (SEM = 2.92 s) and between-day variability (SEM = 2.78 s and 2.19 s between first vs. third set, and second vs. third set, respectively). τmVÌO2$\tau {\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ (28.5 ± 4.17 s) correlated significantly (P < 0.05) with Smax (r = -0.66), VT1 (r = -0.64) and time constant of the p VÌO2${\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ on-kinetics (r = 0.69). These findings indicate that NIRS-derived mVÌO2${\rm{m}}{\dot{V}_{{{\rm{O}}_{\rm{2}}}}}$ kinetics in the gastrocnemius following moderate running exercise is a useful and reliable parameter to assess muscle oxidative capacity.
Assuntos
Corrida , Espectroscopia de Luz Próxima ao Infravermelho , Adolescente , Adulto , Teste de Esforço/métodos , Feminino , Humanos , Cinética , Masculino , Músculo Esquelético/metabolismo , Oxigênio/metabolismo , Consumo de Oxigênio/fisiologia , Reprodutibilidade dos Testes , Adulto JovemRESUMO
do Nascimento Salvador, PC, Dal Pupo, J, De Lucas, RD, de Aguiar, RA, Arins, FB, and Guglielmo, LGA. The V[Combining Dot Above]O2 kinetics of maximal and supramaximal running exercises in sprinters and middle-distance runners. J Strength Cond Res 30(10): 2857-2863, 2016-The aim of this study was to compare the V[Combining Dot Above]O2 kinetics parameters during maximal and supramaximal running exercises in sprinters (SPR) and middle-distance runners (MDR). Twelve SPR (age 20.6 ± 3.4 years; and body mass 74.9 ± 6.2 kg) and 10 MDR (age 17.6 ± 1.4 years; and body mass 70.1 ± 11.8 kg) performed, on different days, a maximal incremental running test for determination of the velocity at maximum oxygen uptake (vV[Combining Dot Above]O2max) and 2 constant-speed tests for analysis of V[Combining Dot Above]O2 kinetics at 100 and 120% of vV[Combining Dot Above]O2max. The MDR presented significantly higher values for the critical speed (18.0 ± 1.0 vs. 14.2 ± 1.0 km·h), vV[Combining Dot Above]O2max (19.4 ± 0.7 vs. 17.2 ± 0.8 km·h), and time to exhaustion at 100% (437 ± 53 vs. 366 ± 49 seconds) than the SPR (p ≤ 0.05). However, the SPR demonstrated greater values for the anaerobic distance capacity (281.3 ± 66.1 vs. 208.0 ± 43.4 m). Although the mean response time and the time to attain the V[Combining Dot Above]O2max of the V[Combining Dot Above]O2 kinetics was higher in the maximal than supramaximal running speed (p ≤ 0.05), no difference was found in these parameters as well for V[Combining Dot Above]O2 slow component (p > 0.05) between the groups. This study showed that different aerobic and anaerobic characteristics in MDR and SPR did not affect the V[Combining Dot Above]O2 kinetics in maximal and supramaximal intensities within the severe-intensity domain. From a practical perspective, parameters of V[Combining Dot Above]O2 response may provide helpful information for training control as the duration of stimulus close to V[Combining Dot Above]O2max.
Assuntos
Teste de Esforço/métodos , Consumo de Oxigênio/fisiologia , Corrida/fisiologia , Adolescente , Adulto , Atletas , Estudos Transversais , Exercício Físico/fisiologia , Humanos , Cinética , Masculino , Oxigênio/metabolismo , Adulto JovemRESUMO
Although the amount of evidence demonstrating the beneficial effects of ischemic preconditioning (IPC) on exercise performance is increasing, conclusions about its efficacy cannot yet be drawn. Therefore, the purposes of this review were to determine the effect of IPC on exercise performance and identify the effects of different IPC procedures, exercise types, and subject characteristics on exercise performance. The analysis comprised 19 relevant studies from 2000 to 2015, 15 of which were included in the meta-analyses. Effect sizes (ES) were calculated as the standardized mean difference. Overall, IPC had a small beneficial effect on exercise performance (ES = 0.43; 90% confidence interval [CI], 0.28 to 0.51). The largest ES were found for aerobic (ES = 0.51; 90% CI, 0.35 to 0.67) and anaerobic (ES = 0.23; 90% CI, -0.12 to 0.58) exercise. In contrast, an unclear effect was observed in power and sprint performance (ES = 0.16; 90% CI, -0.20 to 0.52). In conclusion, IPC can effectively enhance aerobic and anaerobic exercise performance.
Assuntos
Desempenho Atlético/fisiologia , Precondicionamento Isquêmico , Educação Física e Treinamento/métodos , Teste de Esforço , Humanos , Precondicionamento Isquêmico/métodos , Aptidão Física/fisiologiaRESUMO
High-intensity interval training applied at submaximal, maximal, and supramaximal intensities for exercising at V[Combining Dot Above]O2max (t95V[Combining Dot Above]O2max) has shown similar adaptation to low-volume sprint interval training among active subjects. Thus, the aim of the present study was to investigate t95V[Combining Dot Above]O2max during 2 different intermittent exercises in the severe-intensity domain (e.g., range of power outputs over which V[Combining Dot Above]O2max can be elicited during constant-load exercise) and to identify an exercise protocol that reduces the time required to promote higher aerobic demand. Eight active men (22 ± 2 years, 72 ± 5 kg, 174 ± 4 cm, 47 ± 8 ml·kg·min) completed the following protocols on a cycle ergometer: (a) incremental test, (b) determination of critical power (CP), (c) determination of the highest constant intensity (IHIGH) and the lowest exercise duration (TLOW) in which V[Combining Dot Above]O2max is attained, and (d) 2 exercise sessions in a randomized order that consisted of a constant power output (CPO) session at IHIGH and a decreasing power output (DPO) session that applied a decreasing work rate profile from IHIGH to 110% of CP. Time to exhaustion was significantly longer in DPO (371 ± 57 seconds vs. 225 ± 33 seconds). Moreover, t95V[Combining Dot Above]O2max (186 ± 72 seconds vs. 76 ± 49 seconds) and O2 consumed (29 ± 4 L vs. 17 ± 3 L) were higher in DPO when compared with the CPO protocol. In conclusion, data suggest that the application of a DPO protocol during intermittent exercise increases the time spent at high percentages of V[Combining Dot Above]O2max.