Side note: This article contains excerpts from my book Next Level Strength Training.

When it comes to designing strength training programs, there are only a handful of variables you can change. These variables include (among others):

• How many repetitions you perform

• How often you train

• Which exercises you choose

• How many sets you do

• Whether you perform a full range of motion in the movement or only partials

• The speed with which you perform an exercise

Training volume, intensity and frequency are all interdependent factors. Generally speaking, the lower your training intensity, the more volume you need in order to reap rewards and vice versa. Likewise, when frequency is high (i.e. daily training or multiple training sessions per day), intensity and volume can't remain high for long periods of time as this will compromise the body's ability to recover, leading to plateaued or even diminished strength levels and possibly overtraining.

In this installment of the Research Corner, I'll try and boil down what really constitutes effective training parameters for the natural, non-gifted strength trainee with the goal of strength and hypertrophy gains as far as the amount of total sets is concerned.

Single vs. Multiple Sets - The Ongoing Debate

Regarding training for strength and size, some people audaciously claim that one single set (often taken to the point of failure) is all that is needed for producing maximum strength and muscle gains. (1-5)

The vast body of evidence in the scientific literature does not support this notion.

In fact, in the light of current research on the whole single vs. multiple set discussion, multiple-set protocols are clearly in the lead. (6-9)

Kramer and colleagues noted that multiple sets not performed to failure yield superior gains in 1RM squat strength compared to one set to failure in moderately trained subjects. (10)

Rhea and others demonstrated that when intensity is kept equal, multiple sets produce greater strength gains in both the upper and lower body than one set in a periodized training program. (11)

Wolfe et al. located and retrieved 16 studies conducted between 1962-2002 that addressed the single vs. multiple set discussion in resistance training. Their findings indicate that single-set programs result in similar strength gains as multiple-set programs for an initial short training period in untrained individuals. However, as progression occurs and higher gains are desired, multiple-set programs are more effective for trained individuals. Thus, for programs with an extended duration, multiple sets are superior to single sets for gaining strength. (12) 

Moreover, Krieger and colleagues found that 2 to 3 sets per exercise are associated with 46% greater strength gains than 1 set in both trained and untrained subjects. (13)

For muscle hypertrophy, 2-3 sets per exercise are more effective than 1 set (40% greater size gains with multiple vs. single set) in both trained and untrained subjects. (14)

Now here's where things get really interesting... and I apologize in advance if your eyes are glazing over already. Feel free to come back to this part at a later time (or never).

According to the research papers by Krieger quoted above, there appears to be no significant difference between 2-3 sets per exercise and 4-6 sets per exercise in terms of strength gains, although there may be a corresponding increase in hypertrophy in relation to a higher number (≥ 4) of sets performed. However, whether 2-3 sets and 4-6 sets per exercise actually do produce different rates of strength and hypertrophy was still inconclusive at the time the research papers were published, as the author of the papers also noted.

A more recent study did indeed find a difference. Researchers from Down Under compared the effect of 1, 4 and 8 sets of squats performed at 80% of 1RM twice a week on strength and hypertrophy on trained individuals. What they found is that the high-volume protocol (8 sets) was superior to 1 and 4 sets both in terms of squatting strength. The 8-set group also saw a significant increase in total body weight possibly suggesting an increase in muscle mass. (15)

After all of this massive theory-wanking, it's evident that multiple sets are more effective than single sets as clearly stated by research.

Or are they?

When you pore over the research papers, you'll quickly notice that the proponents of single-set protocols are able to rip apart pretty much any research paper that is pro multiple-set training, pointing out inconsistencies and flaws in study design. On the other hand, multiple-set advocates accuse the single-set crowd of misinterpreting the data on purpose. Just because a difference didn't reach statistical significance doesn't mean no meaningful effect was observed, which is often the case in this debate - a study demonstrates that multiple set protocols cause greater positive changes in strength and hypertrophy, but that difference is not "statistically significant" so the result is interpreted as proof for no difference between single and multiple set training programs.

Who's Right, Who's Wrong?

You could literally review the current research out there and all it would do is make your head hurt like the time Charlie Sheen woke up in a hospital following a what must have been a stupendously glorious night of binging on a briefcase full of cocaine off random strippers' backs.

Both sides of the single vs. multiple set debate present logical arguments (at least on the surface) and defend their stance with the tenacity of the Grove Street Families gearing up for a turf war with The Ballas somewhere in East Los Santos.

Here's where we stumble upon the limitations of research. Remember when I said earlier that you can use scientific studies to help back up or refute pretty much any point of view? 

Well, what we've got here is a bunch of inconclusive studies and it's not likely a consensus will be reached on the matter among scientists too busy swinging virtual dicks and shooting holes through the opposition's claims any time soon. What we're left with is casting our views on the blatantly obvious empirical evidence, which is hardly inconclusive and too obvious to be ignored.

You'll be hard-pressed trying to find a world-class powerlifter, Olympic lifter or strongman who uses and excels on single-set routines.

The training programs and experiences of most strength/power athletes indicate that multiple sets produce superior results. Likewise, the vast majority of respectable strength & conditioning coaches favor multiple sets when designing programs for their clients.

Let's stop for a moment and think about the practical implications of the 1 set is enough theory. If  - and this is a huge assumption - a single set of a given exercise was enough to maximize hypertrophy and strength gains, it would mean that the human body functioned in a switch on/switch off manner. You go to the gym, perform a moderately heavy set of squats, and you now have milked the potential gains to a full 100%, meaning that all subsequent sets will be useless.

Contrary to that point of view, proponents of the multiple-set theory state that gains are produced in a dose-response manner, which, at least for me, makes much more sense. The first set will have the biggest overall effect, yes, but the following sets will have an impact as well. Even though this effect is smaller (relatively speaking) for each and every set you perform for that same exercise (and at some point one additional set will cease to provide a desired effect), they still do yield an effect that should not be neglected.

"The dose-response is a training principle that states that a given stress or dose will result in a certain response with higher doses eliciting a greater response up to a certain point. After this point of maximal effectiveness, benefits of increased dosages begin to diminish and an overdose is observed.

In the pharmaceutical world, the principle of the dose-response is a very familiar and important concept. Physicians must know the degree of impact that a specific dose of a drug will have in order to prescribe the correct amount. Too little dose will fail to achieve the needed change in health or condition while an overdose may carry severe adverse effects. Similar to pharmaceutical drug prescriptions, exercise professionals prescribe resistance training programs (of varying doses) to elicit the needed or desired degree of strength development. Prescribing too little work will result in a failure to achieve the desired or needed strength gains while too much work could result in overtraining.

The principle of progression states that once an individual has become accustomed to a stimulus, they must add additional stress in order to stimulate continued responses. In other words, the dose must be progressively increased to result in continued adaptation. These principles have been developed through years of research and practice and have continually been supported by such work." (16)

Is There an Optimal Volume for Strength and Hypertrophy?

Short answer: no.

Volume is a highly individual thing. Some people thrive on high volume, whereas others can and do see great gains with only one or two work sets.

How someone responds to a high-volume training plan depends on multiple factors such as age, training age, injury history, ability to recover, external stressors in life, etc. Another thing we need to take into account is that you can't increase volume forever. If 8 sets of squats is better than 4 sets, then surely 16 would be even better? And when 16 sets cease to produce further gains (as all training protocols at some point will) why not go up to 32 sets? Or 100?

Once again, we can merely establish guidelines and go from there...

Peterson and colleagues summarized their findings in the following manner:

• For untrained individuals, maximal strength gains are elicited at an average training intensity of 60% of 1RM, 3 days per week, and with an average training volume of 4 sets per muscle group.

• Recreationally trained non-athletes exhibit maximal strength gains with an average training intensity of 80% of 1RM, 2 days per week, and an average volume of 4 sets per muscle group.

• For advanced athletic populations, maximal strength gains are seen at an average training intensity of 85% of 1RM, 2 days per week, and with an average training volume of 8 sets per muscle group (16 total sets per week per muscle group). (17)

A study by Wernbom et al. established similar specifications, suggesting that hypertrophy in novice to intermediate lifters can be maximized with up to 3-6 sets per muscle group, performed 2-3 times per week (6-18 total sets per week per muscle group). The researchers also noted that advanced lifters probably need even higher volumes to elicit further gains in size. (19)

Summing It All Up

Can you gain muscle by performing only a single set of a given exercise?

Yes.

Can you build strength with a single-set training program?

Absolutely, as long as the principle of progressive overloading is adhered to.

For people interested in general fitness and/or lacking in time, motivation or intestinal fortitude to undergo a more rigorous training plan, a single set is suitable.

Three sets per exercise is an appropriate starting point for someone looking for maximal strength and muscle gains. Adjustments can and should be made from these starting points based on how a trainee responds to a given training protocol. (18) In other words, let your progress or lack of it guide you with training-related decisions; only make changes when what you're doing no longer works.

In practice, the sweet spot for optimal strength and hypertrophy both from a results-oriented and time management standpoint appears to lie somewhere between 2-6 sets per exercise per training session, and a minimum of 2-3 sets per exercise is required to elicit significant gains. Advanced athletic trainees generally need to perform more volume than beginner or intermediate lifters to cause additional training adaptations.

References

(1) Otto, RM. et al. A critical analysis of the single versus multiple set debate. Journal of Exercise Physiology-online. 2006 Feb; 9(1):32–57.

(2) Carpinelli, RN. et al. Strength Training: Single Versus Multiple Sets. Sports Medicine. 1998 Aug; 26(2):73-84.

(3) Carpinelli, RN. et al. Strength Training: Single Versus Multiple Sets [Reply]. Sports Medicine. 1999 Jun; 27(6):409-416.

(4) Winett, RA. Meta-Analyses Do Not Support Performance of Multiple Sets or High Volume Resistance Training. Journal of Exercise Physiology-online. 2004 Oct; 7(5):10-20.

(5) Hass, CJ. et al. Single versus multiple sets in long-term recreational weightlifters. Medicine & Science in Sports & Exercise. 2000 Jan; 32(1):235-242.

(6) Humburg, H. et al. 1-Set Vs. 3-Set Resistance Training: A Crossover Study. The Journal of Strength and Conditioning Research. 2007 May; 21(2):578–582.

(7) Galvao, DA. et al. Single- Vs. Multiple-Set Resistance Training: Recent Developments in the Controversy. The Journal of Strength and Conditioning Research. 2004 Aug; 18(3):660–667

(8) Stone, MH. et al. Athletic Performance Development: Volume Load -1 Set vs. Multiple Sets, Training Velocity and Training Variation. Strength and Conditioning Journal. 1998 Dec; 20(6):22-31.

(9) Byrd, R. et al. Strength Training: Single Versus Multiple Sets [Reply]. Sports Medicine. 1999 Jun; 27(6):409-416.

(10) Kramer, JB. et al. Effects of Single vs. Multiple Sets of Weight Training: Impact of Volume, Intensity, and Variation. The Journal of Strength and Conditioning Research. 1997 Aug; 11(3):143-147.

(11) Rhea, MR. et al. Three Sets of Weight Training Superior to 1 Set With Equal Intensity for Eliciting Strength. The Journal of Strength and Conditioning Research. 2002 Nov; 16(4):525-529.

(12) Wolfe, B. et al. Quantitative Analysis of Single- Vs. Multiple-Set Programs in Resistance Training. The Journal of Strength and Conditioning Research. 2004 Feb; 18(1):35-47.

(13) Krieger, JW. Single Versus Multiple Sets of Resistance Exercise: A Meta-Regression. The Journal of Strength and Conditioning Research. 2009 Sep; 23(6):1890-1901.

(14) Krieger, JW. Single vs. Multiple Sets of Resistance Exercise for Muscle Hypertrophy: A Meta-Analysis. The Journal of Strength and Conditioning Research. 2010 Apr; 24(4):1150-1159.

(15) Marshall, PW. et al. Strength and neuromuscular adaptation following one, four, and eight sets of high intensity resistance exercise in trained males. European Journal of Applied Physiology. 2011 Dec; 111(12):3007-3016.

(16) Rhea, MR. Resolving the Single-Versus Multiple-Set Strength Training Debate. NSCA Hot Topic Series. [no date]

(17) Peterson, MD. et al. Applications of the Dose-Response for Muscular Strength Development: A Review of Meta-Analytic Efficacy and Reliability for Designing Training Prescription. The Journal of Strength and Conditioning Research. 2005 Nov; 19(4):950-958.

(18) Krieger, J. Determining Appropriate Set Volume for Resistance Exercise. Strength and Conditioning Journal. 2010 Jun; 32(3):30-32.

(19) Wernbom, M. et al. The Influence of Frequency, Intensity, Volume and Mode of Strength Training on Whole Muscle Cross-Sectional Area in Humans. Sports Medicine. 2007 Mar;37(3):225-264.