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Aerobic and Resistance Training Sequence
Is There A Better Afterburn Sequence
Len Kravitz, Ph.D.

Article Reviewed:
Drummond, M.J., Vehrs, P.R., Schaalje, G.B., and Parcell, A.C. (2005). Aerobic and resistance exercise sequence affects excess postexercise oxygen consumption. Journal of Strength and Conditioning Research, 19(2), 332-337.

Introduction to the Debate
One of the most time-efficient training methods for clients in completing their aerobic and resistance exercise training sessions is to combine them in the same workout session, a training technique referred to as concurrent training. Perhaps one of the longest lasting and engaging debates for fitness professionals and personal trainers has been the topic of which sequence is better when in combining the two modalities. A previous review in this column (IDEA Personal Trainer, 15(3), 34-37) on concurrent training revealed the following important points about muscle force production. When aerobic exercise precedes strength training, any muscle strength impairments are limited to the muscle groups used in the prior aerobic training. For instance, when cycle ergometry (a lower body cardiovascular modality) was performed first in the concurrent sequence, it was shown to noticeably impair the lower body resistance training workout performance (as measured by submaximal incline leg-press performance). However, this initial cycle ergometry workout (whether performed at a high-intensity or moderate intensity) had no limiting affect upon upper body strength performance (as measured by the bench press).

An imperative looming question in this concurrent training debate has been whether one particular workout sequence elicits a more pronounced post-exercise ‘after-burn’ of calories. The exercise after-burn, scientifically known as EPOC (Excess Post-Exercise Oxygen Consumption) has been previous reviewed in IDEA Fitness Journal (2004, 1(5), 42-47). Briefly, EPOC represents the calories expended above resting (or pre-exercise) values following an exercise bout. This after-burn caloric expenditure period, which has its most prominent effect within the first 2 hours of the exercise session, represents the oxygen consumption above resting level that the body is utilizing to return itself to its pre-exercise state.

This investigation compared the combined effect of resistance and aerobic exercise as well as the different sequences of these two modalities on EPOC. In addition, a recurring question answered by this study was whether the concurrent training session had a more meaningful after-burn as compared to single sessions of aerobics or resistance exercise.

The subjects in this study were 10 physically active males (age = 26 years) who had been performing jogging and strength training for at least 2 days per week for the previous 6 months. Before beginning the testing sessions, all the subjects completed 1-repetition maximum (1-RM) assessments on the resistance exercises performed in the study. This was needed in order to establish the precise workout intensity to be performed in the resistance testing sessions. In addition, the men performed a maximal aerobic capacity test (VO2max) in order to establish the appropriate workout intensity for the study’s aerobic sessions.

Pre-Exercise Procedures
Prior to all 4 exercise testing days, the male subjects ate a similar dinner at 5 pm and reframed from any physical activity for the previous 48 hours. The volunteers also had a similar morning meal at 6 am on each day of testing, which was complemented with a nutritional bar. These nutritional timing and intake controls were implemented because of the importance nutrition has on exercise performance, which can also affect the exercise after-burn. Upon arrival to the exercise physiology laboratory, each subject was asked to lie down in a supine position for 30 minutes where resting metabolic rate (RMR) data was collected for 30 minutes in a very relaxed atmosphere.

The Four Testing Conditions of the Study
To prevent any type of order bias in the testing, the four exercise sessions were systematically arranged for the subjects using a methodical ordering technique referred to as a randomized Latin square design. This was a very important design control utilized by the researchers to accurately compare the 4 testing sessions.
Resistance Only: The volunteers completed 3 sets of 10 repetitions at 70% of their 1RM with a 105-second rest between sets and exercises. Each subject performed the following 7 exercises in this order: bench press, leg press, barbell biceps curl, triceps extension, hamstring curl, latisimus pull down, and knee extension. Five minutes after completing the resistance training exercises, subjects were placed in a supine position where EPOC was recorded up to the 105-minute mark. After each testing session, EPOC values were collected precisely the same for each subject.
Run Only Session: For the treadmill run exercise session, each subject ran for 25 minutes at a stride pace of 70% of their VO2max. Five minutes after completing the treadmill run EPOC was measured as described above.
Run-Resistance: The subjects performed the 25-minute run at 70% of their VO2max. Five minutes after completing the treadmill run, the subjects performed the exact same resistance training bout, at the same intensity and in the same order as they did for the resistance only session. Once again, five minutes after completing the resistance training exercises EPOC was collected as previously described.
Resistance-Run: In this testing condition the resistance training session was completed first and then, following a five-minute break, the 25-minute cardiovascular run on the treadmill was performed. As with all sessions, EPOC was collected following the same data collection procedure for each subject.

Results and Discussion
The EPOC levels returned to pre-exercise values within 40 minutes of all 4 exercise sessions, thus confirming previous research which shows that the prominent effect of the exercise after-burn is within the first 2 hours of exercise. Perhaps the first 10 minutes of EPOC reveal the most meaningful data from this well-designed study. The unit to express EPOC is ml/kg/min, which means milliliters of oxygen, per kilogram of body weight, per minute. It is interesting to note that the resistance only and run-resistance were significantly higher than the resistance-run and the run only sessions. The researchers did not calculate actual calories or provide the data necessary for a reader to calculate caloric expenditure. However, since resting metabolism rate (RMR) was ~3.5 ml/kg/min for the subjects, it is clear at the 10-minute mark that the EPOC was 66% above the RMR for the resistance only and the run-resistance sessions as compared to 45% and 34% above the RMR for the resistance-run and run only sessions, respectively. At 20 minutes post-exercise the resistance only session was 28% above resting RMR as compared to the run only session, which was lowest at 17% above resting RMR.

What Has Been Answered from This Study?
One major answer from this study is that the combined run-resistance or resistance-run sequence did not elicit an exaggerated after-burn (EPOC) response. Secondly, at the intensities of exercise incorporated in this study, it is clear that resistance only and run-resistance had the most meaningful effect on EPOC within the first 10 minutes post-exercise. It is essential to realize that even though resistance training is an anaerobic activity some of the mechanisms that will elevate EPOC following resistance exercises include the re-synthesis of the phosphagen energy system (ATP-PC), lactate removal, and peripheral blood circulation and muscle temperature recovery.
It is also meaningful to discuss the fact that previous research clearly shows that the most profound effect on EPOC is ‘intensity’. Therefore, a follow-up study with the aerobic exercise and resistance exercise sessions being performed at different intensities (i.e., 75%, 80%, 85% of maximum) might be very enlightening to this sequence debate.

Lastly, even though many of the questions on concurrent training are now being scientifically tested and answered, it is important for personal trainers and fitness professionals designing concurrent exercise sessions to always focus on the principle of variety in training. It is well-established that for physiological change to occur as well as for the prevention of psychological boredom, that mixing up the exercises and exercise order will assuredly be a convincing formula for long-lasting exercise success.
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