The debate of whether 1 set versus 3 sets is better for building muscle has been around almost as long as the sport of bodybuilding itself! There have been numerous studies and reviews in recent years which have attempted to answer the question, but the bulk have only produced equivocal results1-3. The conflicting results are thought to be due to a number of factors, namely, the inherit differences in response between individuals to resistance training, poor study design and/or differing training status of the research subjects1.
Measuring Muscle Growth
However, with advances in technology, scientist are now is a position to conduct studies which overcome a lot of these issues. New technologies allow scientists to measure right down to the molecular level of gene expression and protein synthesis. By combining the molecular changes as well as the physical changes (i.e. changes in strength, weight and muscle size) mirroring muscle development, scientists can be more objective in their conclusions about the most effective stimuli for muscle development.
1 Set vs 3 Sets
Armed with these new tools, scientists from Canada set about answering this age-old question once and for all. Their study, which was published in The Journal of Physiology in 2010 resulted in some fascinating findings, which should be of interest to the average bodybuilder4. After recruiting eight resistance-trained men, they were randomly assigned to perform unilateral leg extension (i.e. single leg extensions) exercises at 70% concentric one repetition maximum (1RM) until volitional fatigue for 1 set or 3 sets4. The researchers really wanted to see how the anabolic response differed across a 29-hour period following the resistance exercise. For this reason, measurements were taken at baseline and then at 5 hours, 24 hours and 29 hours following the resistance exercise bout.
Muscle Growth After 1 Day
As expected both types resulted in an increase in muscle protein synthesis after 5 hours, but even after this short period of time 3 sets resulted in a greater amplitude in muscle protein synthesis that 1 set (i.e 3.1 vs 2.3-fold above baseline). However, the key findings came when they compared muscle protein synthesis at 24 and 29 hours. Muscle protein synthesis had dropped back to resting levels at 29 hours in the 1 set group, whereas muscle protein synthesis was still elevated above baseline (i.e. 2.3-fold) in the group performing 3 sets4. It’s important to clarify that study subjects only completed one or three sets of single leg extensions, with no other resistance exercises. Those subjects performing three sets rested for 2 mins between sets.
So while many avid bodybuilders and gym goers already employ multiple sets as part of their regular training regime in the belief that its superior for muscle growth; it’s good to know that there is good scientific evidence out there that three sets is in fact better than one when it comes to building muscle. In fact, one surprising finding of this study was just how little resistance exercise is needed to stimulate muscle protein synthesis for up to 30 hours.
1. Krieger JW. Single versus multiple sets of resistance exercise: a meta-regression. J Strength Cond Res. 2009;23(6):1890-901.
2. Krieger JW. Single vs. multiple sets of resistance exercise for muscle hypertrophy: a meta-analysis. J Strength Cond Res. 2010;24(4):1150-9.
3. American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687-708.
4. Bird NA, et al. Resistance exercise volume affects myofibrillar protein synthesis and anabolic signalling molecule phosphorylation in young men. J Physiol. 2010;588(16):3119–3130.