Single vs multiple sets? Finally the answer (again)

March 21st, 2010  |  Published in Stumpblog  |  5 Comments

We’ve talked about single vs multiple sets on this site before. In that case, the study examined the relationship between sets and strength gain. This study examines the relationship between set number and muscle mass gain. Basically: multiple sets are better than single sets for adding muscle mass. You’re welcome.

Krieger, James W. Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. J Strength Cond Res 24(4): 1150-1159, 2010-

Previous meta-analyses have compared the effects of single to multiple sets on strength, but analyses on muscle hypertrophy are lacking. The purpose of this study was to use multilevel meta-regression to compare the effects of single and multiple sets per exercise on muscle hypertrophy. The analysis comprised 55 effect sizes (ESs), nested within 19 treatment groups and 8 studies. Multiple sets were associated with a larger ES than a single set (difference = 0.10 +/- 0.04; confidence interval [CI]: 0.02, 0.19; p = 0.016). In a dose-response model, there was a trend for 2-3 sets per exercise to be associated with a greater ES than 1 set (difference = 0.09 +/- 0.05; CI: -0.02, 0.20; p = 0.09), and a trend for 4-6 sets per exercise to be associated with a greater ES than 1 set (difference = 0.20 +/- 0.11; CI: -0.04, 0.43; p = 0.096). Both of these trends were significant when considering permutation test p values (p < 0.01). There was no significant difference between 2-3 sets per exercise and 4-6 sets per exercise (difference = 0.10 +/- 0.10; CI: -0.09, 0.30; p = 0.29). There was a tendency for increasing ESs for an increasing number of sets (0.24 for 1 set, 0.34 for 2-3 sets, and 0.44 for 4-6 sets). Sensitivity analysis revealed no highly influential studies that affected the magnitude of the observed differences, but one study did slightly influence the level of significance and CI width. No evidence of publication bias was observed.

In conclusion, multiple sets are associated with 40% greater hypertrophy-related ESs than 1 set, in both trained and untrained subjects.

For more on James Krieger, check out his website The BS Detective and the Journal of Pure Power.


  1. Sharon says:

    March 22nd, 2010at 7:46 am(#)

    Thank you for clearing that up, Krista.

  2. Sasha says:

    March 22nd, 2010at 11:33 pm(#)

    Krista, I think anyone who spent any time in the gym and made any significant progress there, be it strength or hypertrophy, knows the answer.

    One-two sets are great to get back into training after a long break or to just have a light workout.

    To me it’s not clear if it is beneficial in terms of time/results ratio to go beyond 3 work sets for somebody whose goal is “general fitness”.

  3. kirsty says:

    March 24th, 2010at 1:48 am(#)

    :-( I did so like thinking that one set would do the job. Much easier to manage in a busy gym on limited time. Damn but I dislike multiple sets.

  4. Katie says:

    April 12th, 2010at 11:07 am(#)

    Thanks for posting the study. I recently came across an old post from Alwyn Cosgrove’s website:

    Back in 2000, a study published in the Journal of Strength and Conditioning Research compared equal-volume resistance training over one day or three days per week. [1] The participants in the study were experienced lifters. Group one performed the entire workout — three sets of each exercise — on one day. Group two performed the same volume of work, but spread it out over three days. So they did one set of each exercise in each workout.

    The researchers found that the once-per-week group achieved just 62 percent of the strength improvements of the three-times-per-week group, and also gained less muscle. The men in the second group put on nine pounds of muscle, vs. four pounds for those in the first group.

    This gives us an idea of how to start our training hack: It’s better to reduce volume per workout than it is to reduce frequency. So if you work out three times a week, it’s better to make those workouts shorter than to do longer workouts less often.

    I realize there are several differences in the studies, but just thought it was interesting that the conclusions from both almost seem to observe opposite results (at least from a layperson’s pov).


  5. James Krieger says:

    April 16th, 2010at 2:27 pm(#)


    I am the author of the recent meta-analysis. The results of my meta-analysis do not contradict the results of the study you mention, because they were looking at different things.

    My paper looked at the effects of the number of sets, when everything else is held constant (like frequency).

    The paper you mention looked at the effects of frequency, when training volume (in total # of sets per week) is held constant.

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