Sequential or Alternating Resistance Training for Maximal Size, Strength and Endurance Gains!? Plus: Basic Blueprint for a 2x2 Day Alternating Muscle Split Workout

If you want to try something new, but feel that this is a bit over the top, why don't you try an alternate workout regimen to escape the daily grind?

It's funny and sad that studies like the one at hand, which investigate basic training principles and their effect on your real world results in the gym are so scarce. I mean, let's be honest. With a few exceptions, all of us will probably get much more out of training optimization than of any available supplement and maybe even drug. As far as supplements goes, you are bombarded with unwarranted claims and the occasional non-significant (per design) study on newly available products. On the training side of things, on the other hand, there is little to no innovation - probably for a good reason, but still: Would you be able to tell me for sure if and why training sequentially, i.e. finishing all sets of one exercise, is "better" than alternating training, where you would, for example do a set of leg curls followed immediately by leg extensions (not necessarily without rest)?

What's better sequential or alternating?

I see, you are scratching your head... well, maybe you'll feel enlightened, after having read what Hamid Arazi, Siavash Rahmati and Samira Zaheri from the Department of Exercise Physiology, Faculty of Sport Sciences at the University of Guilan in Rasht, Iran have found in their most recent study on the effectiveness of 10 weeks of alternating vs. sequential push and pull training of the large and small muscle groups in 24 healthy male athletes (age 22y, BF% 14, weight 72kg) with a history of at least 3-6 months of weight training (Arazi. 2013).

The actual training protocol, the two groups followed was virtually identical except for the exercise order, of course:

• frequency: 3x /week
• rest: 48h between workouts; 2 min between upper, 3 min between lower body ex.
• duration: 70-80min per workout (20 minutes warm-up + cool down) 
• progression: linear, every two weeks - 60%1RM\12reps < 65%1RM\12reps < 70%1RM\10reps < 75%1RM\10reps < 80%1RM\8reps

• exercise selection: 3 sets of leg extensions, leg curls, rows and bench presses for the major and 3 sets of bicep curls and triceps extensions for the smaller muscle groups
• push vs. pull: leg extension, chest press, and triceps extension are push exercises; leg curl, biceps curl and rowing are pull exercises

• sequential training: "Sequence means each exercise is performed for 3 sets (with intervals of rest) and then next exercise starts moving again." (Arazi. 2013)
• alternating training: "Each session was conducted by leg extension (1 set) and leg curl (1 set). The alternative means the opposing muscles (requires push and pull) that were trained alternatively ." (Arazi. 2013)

The main outcome measures were muscle circumference (hypertrophy), muscle strength and muscular endurance, and the results look like this:

Figure 1: Relative changes in arm and thigh circumference (Arazi. 2013)

As you can see in figure 1 the increases in arm and thigh circumference were more yet not statistically significantly more pronounced in the sequential training group. An observation that would suggest that hypertrophy requires a certain amount of body part specific training density, which is obviously reduced it you do one set of one exercise, rest for 2-3 min, do one exercise for the other muscle group and rest for another 2-3 minutes - that's 4-6 minutes of passive and ~1 min of active rest (while you perform the other exercise) between sets and that's imho simply too much to gain.

Figure 2: Changes in muscular strength and endurance (Arazi. 2013)

Both, strength and strength endurance don't show a clear response - overall maybe a marginal benefit for the longer rest times, but certainly not impressive. At least wrt to the increase in strength endurance once could maybe argue that is may be a simple result of an increased total training volume and - maybe even more importantly - more reps per set, when you train alternately instead of sequentially.

Suggested read: "Intra-Set Rest Periods Boost Power (+38%) & Strength Gains (+65%) Without Hampering Skeletal Muscle Hypertrophy" (read more)

Unfortunately, the "discussion" of the results, the authors provide is not exactly helpful in this regards (it is not exactly legible, either, by the way, and I am usually the last to criticize other non-native speakers for their command of the English language).

Still the overall message the researchers formulate in the conclusion to their paper, where it says that it would be "suggested to use the opposing exercises for strengthening agonist –antagonist exercises" (Arazi. 2013) is not totally beside the point. Nevertheless,I'd expect better hypertrophy effects if you reduce the inter-set rest times  from 2 minutes to 60s and from 3 minutes to 90s for the large and small muscle groups, respectively.

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Bottom line: While the study at hand certainly doesn't provide a conclusive answer to the question whether alternate or sequential training is the way to go for strength trainings, my personal experience is that alternating between exercises for antagonistic muscle groups as in a chest / lat,  biceps / triceps, front delts / upper back, and quads / hams + glutes 4- or 2-day split with relatively short inter-set rest periods (90s for larger, and 60s for smaller muscle groups) can be more than just a diversion from the daily grind at the gym.

You can be in and out of the gym in <40 min and still lift a pretty decent amount of weight; and that, at a lower risk of CNS burnout than with a classic super-set training, where you would not rest between the push and pull movements, at all. The latter allows for a relatively high training frequency, but I would still take a day off between workouts, unless you are trying to cut weight at all costs. In that case, a fast paced training split build around the concept of alternating back and forth between exercises for agonist and antagonist can actually be worth way more than hours of classic "cardio" training or HIIT training. Just don't overdo it! While the individual muscles may still get enough rest, any increase in workout density will also increase the load on the central nervous system.

References:

• Arazi H, Rahmati S, Zaheri S. The Effect Of Two Sequence Patterns In Resistance Training On Strength, Muscular Endurance And Circumference In Novice Male Athletes. Hrvat. Športskomed. Vjesn. 2013; 28: 7-13.