One article on PainSci cites Krieger 2010: Strength Training Frequency
PainSci summary of Krieger 2010: ?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.
[This study has been superceded by a newer one, Schoenfeld 2016, with roughly similar conclusions.]
If you’re trying to build muscle size (hypertrophy), how many sets should you do? One set? Two sets? (Red set, blue set?) This is the best review of the evidence to date. While it can’t conclusively settle the issue until there’s more data, it does strongly suggest that “more is better,” and yet at the same time it reaffirms that “less is still actually pretty good.” Single sets will get the job done, which is ideal if your goal is bang-for-buck. If you want to be “hyooge,” though, definitely go with more sets.
Alas, there wasn’t that much data to review, just 8 studies, and only 2 of those included higher numbers of sets. That’s not a lot to work with. But the results are consistent with the more complete data about strength (see Krieger’s 2009 review, Krieger), and strength and muscle size do tend to go together.
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.
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.
- “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 2010:
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:
- Relationships Between Sleep Quality and Pain-Related Factors for People with Chronic Low Back Pain: Tests of Reciprocal and Time of Day Effects. Gerhart 2017 Ann Behav Med.
- Modulation in the elastic properties of gastrocnemius muscle heads in individuals with plantar fasciitis and its relationship with pain. Zhou 2020 Sci Rep.
- Association Between Plantar Fasciitis and Isolated Gastrocnemius Tightness. Nakale 2018 Foot Ankle Int.
- No Added Benefit of Combining Dry Needling With Guideline-Based Physical Therapy When Managing Chronic Neck Pain: A Randomized Controlled Trial. Stieven 2020 J Orthop Sports Phys Ther.
- Effectiveness of customised foot orthoses for Achilles tendinopathy: a randomised controlled trial. Munteanu 2015 Br J Sports Med.