Exercise, Hypertrophy, Studies

April 6, 2016

Is Daily Undulating Periodization Best for Muscle Growth?

If you follow my work you’ll undoubtedly know that our lab has carried out a number of studies seeking to determine the effects of training in different repetition ranges on muscle strength and growth. The overall findings from these studies showed similar increases in hypertrophy between both heavy and moderate rep ranges, as well as moderate and high rep ranges.

However, the choice of rep ranges is not necessarily an either-or proposition; you can in fact combine strategies to potentially achieve greater hypertrophic benefits. Daily undulating periodization (DUP) routines are specifically designed for this purpose. However, no study to date had compared a varied rep approach to traditional constant-rep training using site-specific measures of muscle growth.

Until now.

Our study, just published in the International Journal of Sports Medicine, set out to investigate if muscular adaptations would differ between DUP-style routine and a traditional hypertrophy-style protocol. Here’s the scoop.

What We Did
Nineteen young men with over four years average resistance-training experience were randomly assigned to 1 of 2 experimental groups that trained 3 days per week: a constant-rep protocol (CONSTANT) that trained using a standard bodybuilding rep range of 8-12 RM per set, or a DUP-style varied-rep protocol (VARIED) that trained with 2-4 RM per set on Day 1, 8-12 RM per set on Day 2, and 20-30 RM on Day 3. All subjects performed a total-body routine consisting of the following seven exercises per session: flat barbell press, barbell military press, wide grip lat pulldown, seated cable row, barbell back squat, machine leg press, and machine knee extension. We tested subjects for changes in hypertrophy of the arm flexors, elbow flexors and quads, as well as maximal strength in the squat and bench press, and upper body muscle endurance. Training was carried out over an 8-week period, with testing done pre- and post-study.

What We Found
Both groups significantly increased markers of muscle strength, muscle thickness, and local muscular endurance. No statistically significant differences were found between conditions in any of the outcomes studied. Sounds like it really doesn’t matter which option you choose, right?

Well, not so fast…

It’s important to understand that the term “statistically significant” simply refers to the probability of results being due to chance at a predetermined level of 5%. This binary method of determining probability has been widely criticized by those in the know about statistics, who proclaim that practical conclusions cannot be drawn merely on the basis of whether a p-value passes a specific threshold. Rather, probability exists on a continuum, and in this regard the p-values (a measure of probability) in our study favored the VARIED condition in several outcome measures. Moreover, magnitude-based statistics (i.e. effect sizes) indicated a benefit to the VARIED condition for upper body hypertrophy, strength, and muscular endurance; no effect size differences were noted for lower body outcomes.

What are the Practical Implications
The study showed a potential benefit – albeit small – to varying repetitions across a spectrum of ranges for increasing upper body muscle strength and hypertrophy. Whether the differences between the varied versus constant rep approach seen in our study would amount to practically meaningful improvements is specific to the individual. For the average gym-goer it probably wouldn’t be of much consequence; alternatively, to a bodybuilder or competitive athlete it very well may. It’s not clear why these findings did not translate into similar differences in lower body muscular adaptions, but based on our findings either approach would seem to be an equally viable choice for leg training.

It’s important to note that this was a relatively short-term study, lasting a total of 8 weeks. When factoring in missed sessions, this means subjects in VARIED trained in each loading zone for a total of only 7-8 sessions over the course of the study period. If the differences in upper body outcomes favoring VARIED would persist over time – highly speculative but certainly possible – the magnitude of results could widen and thus be potentially meaningful for a wide array of fitness enthusiasts.

Another important point is that volume load was consistently lower across all conditions (pushing exercises, pulling exercises, leg exercises, and total volume of all exercises) in VARIED as compared to CONSTANT. This indicates that training in a varied fashion provides comparable or better results with less volume load than training at a constant 8-12 RM repetition range. It also suggests that if volume load were equated between conditions, there might have been even better results for the varied approach.

In sum, our study shows that both varied and constant loading schemes are viable strategies to increase strength and hypertrophy in resistance-trained men. The data suggest a potential modest benefit to varying loading ranges over time, at least for maximizing upper body muscular adaptations. Importantly, findings clearly indicate that contrary to what many believe, training in the “hypertrophy zone” (6-12 RM) is not superior for building muscle. When considering the practical implications of the findings, remember that exercise prescription is always a function of the needs/abilities/goals of the individual.


  1. Brad when you say that Volume Load was consistently lower in the varied group, do you mean that they did less sets per workout? As in, the constant group may have consistently performed 4×8-12 but the DUP group only did 3?

    Comment by Travis — April 6, 2016 @ 7:24 am

  2. If you have clients, or you yourself, are precluded from heavy lifting, do you think using a moderate and light loading scheme would be more beneficial than just a moderate loading scheme?

    Comment by Jason — April 6, 2016 @ 10:12 am

  3. Yeah, I would have liked to see more sets in the lower rep range to bring the overall volume closer to the 8 to 12 range volume.

    Comment by Randy — April 6, 2016 @ 10:50 am

  4. Hi Brad,

    Thanks a lot for sharing! Question: Was volume load not equated primarily for practical reasons (i.e. time in the gym)?

    Also, I’m curious as to how much less volume on a DUP program one could get away with while still achieving at least equal results to the constant rep range.

    Thanks for all of the awesome work you’re doing to further our field!

    Comment by Logan — April 6, 2016 @ 11:05 am

  5. Just got a chance to read the full text between clients. I see now that the study design was not aimed at equating volume. So please ignore my original question! LoL

    Comment by Logan — April 6, 2016 @ 12:34 pm

  6. Travis:

    No, sets were equated. Volume load refers to reps x sets x load. What seemed to happen is that the total amount of weight lifted did not increase to the same extent for whatever reason in the DUP-style group to a greater extent compared to the constant group, but this did not have a negative effect on results.

    Comment by Brad — April 6, 2016 @ 4:04 pm

  7. Randy:

    The volume load in the first few weeks of training was similar between conditions. The discrepancies in volume load occurred over time for whatever reason.

    Comment by Brad — April 6, 2016 @ 4:05 pm

  8. Cheers Logan!

    Comment by Brad — April 6, 2016 @ 4:05 pm

  9. Jason:

    Always tough to answer hypotheticals. Training necessarily must be tailored to the needs and abilities of the individual. Limitations have to be considered as part of the process. Certainly removing heavy load training is an option; whether it’s the best option would depend on the particulars of the situation.

    Comment by Brad — April 6, 2016 @ 7:56 pm

  10. Brad, One thing I appreciate about your work is you often comment about the time implications of a protocol. I know the study did not address this as it was fully body v. fully body. But I would imagine that running a classical DUP 3x total body routine would require a far larger time commitment per session than any sort of split routine, particularity with moderate rep ranges. This is particularly true if resting 3 minutes between sets on 2-4 reps.

    Also regarding your meta-analysis on rest intervals I think it would be interesting to time match a study. 1 minute v. 2 minute v. 3 minute with a time limit of 45 minutes or so. Does the decreased rest allow more volume which in the same time frame yields similar results? IF 1 minute or 90 second may be more optimal for people with limited training time.

    Thanks for your awesome work!

    Comment by Brad — April 8, 2016 @ 9:35 am

  11. Brad-
    Similar to the above comment-
    Did workouts last the same amount of time? If volume load was higher, but workout duration was the same, this has a lot of practical significance.


    Comment by Sawyer — April 8, 2016 @ 12:27 pm

  12. Sawyer and Brad:

    We did not time the workouts in this study, but observationally the durations were not that much different between conditions. The two primary factors that influence workout duration are the number of sets and the rest interval – both of these variables were controlled between conditions so total time would necessarily be rather similar.

    Comment by Brad — April 8, 2016 @ 1:45 pm

  13. Hey Brad,
    I know studies are costly and difficult to run but is there anything in the works to compare a high, moderate, and low intensity DUP like the above study with a high and low intensity DUP?

    I’m just curious if the moderate range makes any difference given that theoretically the high intensity (85% or higher of 1RM) would hit the type II fibres and the low intensity (50-60% 1RM) would hit the type Is.

    Comment by Jason — May 5, 2016 @ 10:53 am

  14. Is it possible to know how many sets were performed in the Varied group? I’m asking because I had planned to transition to DUP, and am struggling with the number of sets to do while at, say, 15 10 & 5 RM’s – whether sets should be three at all RM’s or, if at the 10 RM, I should od 4 sets, and the 5 RM I should do 5 sets. Thanks for any help -Marc

    Comment by Marc Roberson — June 6, 2016 @ 11:06 am

  15. Marc:

    We used 3 sets for all groups across all exercises. That doesn’t mean other options aren’t equally viable or even superior.

    Comment by Brad — June 6, 2016 @ 6:46 pm

  16. I really wonder what the underlying effect of the success of DUP routines is. Maybe it is, because there is a good chance each athlete trains in its individual/optimal rep range at least once a week. This study from 2008 (http://www.ncbi.nlm.nih.gov/pubmed/18550956) revealed a highly individual response to different rep ranges.
    A study “individual rep range vs DUP” would be great and shed new light onto the whole subject.

    Nonetheless, congrats to this study. Well done!

    Comment by Sebastian — June 9, 2016 @ 4:09 pm

  17. Sebastian:

    Agreed, it would make for a good study. I’d note, though, that the Beaven et al study looked at strength gains, not hypertrophy. I’d surmise that the response would show similar effects on growth, but that needs to be established.

    Comment by Brad — June 15, 2016 @ 6:35 am

RSS feed for comments on this post.

Sorry, the comment form is closed at this time.