PainSci summary of Krieger 2009?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★★★☆4-star ratings are for bigger/better studies and reviews published in more prestigious journals, with only quibbles. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.
More is better, but not by much. This meticulous review of 8 tests of multiple sets versus one set of strength training shows that more sets do have a greater effect, but not proportionately: a clear case of diminishing returns. Three sets do not have even double the effect of one, not even close. Specifically, 2-3 sets are 40% better than just one, and only 20% more for 4-6 sets. The article begins by pointing out that “some authors have argued that a single set per exercise is all that is necessary for all populations and that further gains are not achieved by successive sets.” These results show the truth is in the middle, as it so often is: more sets probably are better, but nowhere near proportionate to the time and effort required. The author writes, “If time is a limiting factor, then single sets can produce hypertrophy, but improvements may not be optimal.” Time is indeed a factor — a huge factor — for the great majority of people.
The studies analyzed were all under-powered, but with a good analysis like this they can produce a pretty trustworthy conclusion.
Carpinelli, a critic of much exercise science, did not like this paper, but Krieger defended himself quite persuasively on his blog, Weightology.
original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
There has been considerable debate over the optimal number of sets per exercise to improve musculoskeletal strength during a resistance exercise program. The purpose of this study was to use hierarchical, random-effects meta-regression to compare the effects of single and multiple sets per exercise on dynamic strength. English-language studies comparing single with multiple sets per exercise, while controlling for other variables, were considered eligible for inclusion. The analysis comprised 92 effect sizes (ESs) nested within 30 treatment groups and 14 studies. Multiple sets were associated with a larger ES than a single set (difference = 0.26 +/- 0.05; confidence interval [CI]: 0.15, 0.37; p < 0.0001). In a dose-response model, 2 to 3 sets per exercise were associated with a significantly greater ES than 1 set (difference = 0.25 +/- 0.06; CI: 0.14, 0.37; p = 0.0001). There was no significant difference between 1 set per exercise and 4 to 6 sets per exercise (difference = 0.35 +/- 0.25; CI: -0.05, 0.74; p = 0.17) or between 2 to 3 sets per exercise and 4 to 6 sets per exercise (difference = 0.09 +/- 0.20; CI: -0.31, 0.50; p = 0.64). There were no interactions between set volume and training program duration, subject training status, or whether the upper or lower body was trained. Sensitivity analysis revealed no highly influential studies, and no evidence of publication bias was observed. In conclusion, 2 to 3 sets per exercise are associated with 46% greater strength gains than 1 set, in both trained and untrained subjects.
- “Single versus multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis,” James W Krieger, Journal of Strength & Conditioning Research, 2010.
- “Single versus multiple sets of resistance exercise: a meta-regression,” James W Krieger, Journal of Strength & Conditioning Research, 2009.
- “Individual Differences: The Most Important Consideration for Your Fitness Results that Science Doesn’t Tell You,” James Krieger and Bret Contreras, Bretcontreras.com.
- “Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis,” Brad J Schoenfeld, Dan Ogborn, and James W Krieger, Journal of Sports Science, 2016.
- “Strength and hypertrophy adaptations between low- versus high-load resistance training: A systematic review and meta-analysis,” Brad J Schoenfeld, Jozo Grgic, Dan Ogborn, and James W Krieger, Journal of Strength & Conditioning Research, 2017.
- “Resistance Training Volume Enhances Muscle Hypertrophy,” Brad J Schoenfeld, Bret Contreras, James Krieger, Jozo Grgic, Kenneth Delcastillo, Ramon Belliard, and Andrew Alto, Medicine & Science in Sports & Exercise, 2018.
Specifically regarding Krieger 2009:
One article on PainScience.com cites Krieger 2009 as a source:
- PS Strength Training Frequency — Less is more than enough: go to the gym less frequently but still gain strength fast enough for anyone but a bodybuilder
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Gronau 2017 Comprehensive Results in Social Psychology.
- The neck and headaches. Bogduk 2014 Neurol Clin.
- Agreement of self-reported items and clinically assessed nerve root involvement (or sciatica) in a primary care setting. Konstantinou 2012 Eur Spine J.
- Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury: A Systematic Review and Meta-analysis. Morelli 2017 Am J Sports Med.
- Association of Spinal Manipulative Therapy With Clinical Benefit and Harm for Acute Low Back Pain: Systematic Review and Meta-analysis. Paige 2017 JAMA.