DOES AEROBIC AND STRENGTH EXERCISE SEQUENCE IN THE SAME SESSION AFFECT THE OXYGEN UPTAKE DURING AND POSTEXERCISE? JOSE ´ VILACXA ALVES, 1 FRANCISCO SAAVEDRA, 1 ROBERTO SIMA ˜ O, 1,2 JEFFERSON NOVAES, 1,2 MATTHEW R. RHEA, 3 DANIELLE GREEN, 4 AND VICTOR MACHADO REIS 1 1 Research Center for Sport, Health, and Human Development, University of Tra´s-os-Montes and Alto Douro (UTAD), Vila Real, Portugal; 2 School of Physical Education and Sports, Rio de Janeiro Federal University, Rio de Janeiro, Brazil; 3 RACE Rx Academy of Exercise Sciences, Logan, Utah; and 4 A.T. Still University Human Movement Program, Mesa, Arizona ABSTRACT Vilac xa Alves, J, Saavedra, F, Sima ˜ o, R, Novaes, J, Rhea, MR, Green, D, and Machado Reis, V. Does aerobic and strength exercise sequence in the same session affect the oxygen uptake during and postexercise? J Strength Cond Res 26(7): 1872–1878, 2012—Concurrent training is a strategy employed in both general fitness and sports conditioning. The purpose of this study was to compare the responses of _ VO 2 in different combinations of strength exercise with aerobic interval exercise. Eight men (23.6 6 4.2 years, 178 6 6.3 cm, 77 6 7.9 kg, 7.67 6 1.95% body fat) completed 3 combinations of strength training (ST) and aerobic training (AT) in a randomized order with a 7-day recovery period: AT before ST exercises, AT between 2 blocks of ST exercises, and AT after ST exercises. The ST comprised 4 exercises performed in 3 sets of 10 reps and 2 exercises, abdominal crunch and lumbar extension, performed in 3 sets of 30 and 20 reps, respectively. The AT consisted of a 20-minute interval cycling. There were no significant differences in the values of absolute or relative _ VO 2 , in the heart rate (HR) and in the respiratory exchange ratio (RER) when the 3 sessions (during + postexercise measure- ments) were compared (values are mean 6 SD). Analyzing only ST in each session, differences were detected in the RER values (F = 4.714; p , 0.05; h 2 = 0.308) between AT before ST and AT in the middle of ST (1.01 6 0.97 vs. 1.11 6 0.07, respectively). In all sequences, there was a significant increase (p , 0.05) in the values of relative and absolute _ VO 2 and HR, and a significant decrease in RER values (p , 0.05) from the first to the second part of the ST session. The values of absolute or relative _ VO 2 , HR, and RER did not vary significantly among the 3 sessions as compared with the AT after ST. These data support the hypothesis that ST and AT, when performed in sequence in the same session, do not seem to affect the overall oxygen consumption during the exercise session. Therefore, training sessions may incorporate both modalities without apparent impact on aerobic exercise. KEY WORDS cardiovascular exercise, resistance exercise, energy expenditure, concurrent training INTRODUCTION T he acute metabolic demands of strength training (ST) exercise have been investigated by previous studies, and their results have shown significantly larger increases in oxygen uptake ( _ VO 2 ) and energy expenditure (EE), during and after exercise, depending on variables, such as muscle mass (24), lifting velocities (14), number of sets (13), number of repetitions (31), workload (38), training volume (16), rest intervals (31), or exercise order (7). Similarly, research on the use of aerobic training (AT) exercise showed increases in exercise _ VO 2 , which are concomitant with increases in exercise intensity (26,34) and are larger when AT is preceded by ST exercise (17). Additionally, studies have shown that when performing intermittent aerobic exercise (20,23) and when performing at high and supramaximal intensities (20,30), a significant increase in postexercise oxygen consumption (EPOC) is present. The combination of AT and ST in the same-session training is very common in physical fitness training programs (1) and athletic programs (5,29) because of time constraints and convenience. However, training including aerobic and strength exercises performed in a single session, known in the literature as concurrent training, presents a specific challenge, especially among different populations (21). Fatigue generated from one mode of exercise may negatively influence the quantity and quality of exercise in the other mode (21). Few studies have addressed the sequence of ATand ST in the same session and its influence on _ VO 2 during (27) and Address correspondence to Jose ´ Vilac x a Alves, josevilaca@utad.pt. 26(7)/1872–1878 Journal of Strength and Conditioning Research Ó 2012 National Strength and Conditioning Association 1872 Journal of Strength and Conditioning Research the TM Copyright © National Strength and Conditioning Association Unauthorized reproduction of this article is prohibited.