One of the variables you can manipulate when you train for strength or hypertrophy is the number of sets you do. Some people do 5 or 6 while others do only a single set. On average, most people do 3 or 4 sets when they’re trying to build muscle size or strength. The question is whether more sets lead to greater gains.
Are More Sets Better?
It might seem like the more sets you do the better, yet there has to be a point of diminishing returns. Isn’t that true of everything? The goal is to stress the muscles you’re working and force them to adapt without overtraining them. The goal is to sufficiently damage the muscle fibers and let them rebuild. Beyond a certain number of sets, you’ve done your job.
So, what is the optimal number of sets?
These days, some fitness trainers preach the single-set approach – one set to failure – but does science support this mode of training? For building strength, this may not be the best approach. A study published in the Journal of Strength and Conditioning Research in 2009 looked at strength gains when participants did a single set compared to when they did 2 to 3 sets. The multi-set group won out. In fact, their strength gains were 46% greater, on average.
Yet, there seems to be diminishing returns once you get past 2 to 3 sets. When participants did 4 to 6 sets, improvements in strength were only 20% greater. In this case, you have to weigh the additional time involved in doing 4 to 6 sets against the additional gains. In this case, sticking with 2 to 3 sets would be most time expedient, considering the added gains with 4 to 6 sets isn’t great.
Some studies looking at the issue of strength training and number of sets fail to control all of the other training variables such as the type of exercise, exercise order, etc. However, a 2007 study in the Journal of Strength and Conditioning Research did tightly control for other variables. The interesting conclusion of this study was 3 sets were better than 1 for lower body strength gains and hypertrophy but 3 were no better than 1 for upper body strength and hypertrophy gains.
Why did the number of sets make a difference for lower body strength gains but not for upper body? One possible explanation is that most lower body exercises are compound movements, meaning they activate multiple muscle groups as well as big muscles. When you work big muscles simultaneously with moves like squats and deadlifts, it elicits a greater anabolic effect than working smaller upper body muscles.
While most studies show that 3 sets are better than 1 for strength and hypertrophy, two studies found no difference in strength and hypertrophy gains with 1 versus 3 in non-professional, trained weight lifters. Keep in mind that a number of factors might impact the results – the type of exercise performed, the age of the weight trainers, gender, and how well trained they are. There aren’t a lot of studies out there that have controlled for all of these variables.
All in all, based on the research that’s out there, you can expect greater gains in strength and size if you do 3 sets as opposed to 1. On the other hand, going beyond 3 will only deliver slightly greater gains and you have to weigh that against the extra time you’re spending doing more sets. It might be better to devote that time to additional exercises.
One Set Weight Training as a Time Saver
Where single sets serve a useful purpose is when you’re so pressed for time that training time is at a premium. A single set that works each muscle group is enough of a stimulus to maintain the muscle and strength that you currently have until have more time to train. You might even work single set days into your workouts as a way to vary the stimulus you place on your muscles. You don’t want to get into the 3 sets of the same exercises every time mode. Your muscles are masters at adapting to routine and you need to change things up.
Another reason that a single set isn’t the best approach routinely is that it’s hard to maximize the results you get on a single set. Your first set warms up your muscles, blood flow increases to the muscles you’re working, and the connection between your brain and muscles to give your best performance. A single set doesn’t allow you to do that. Plus, when you consider the factors that stimulate muscle growth, prolonging the time the muscle is under tension, being one of them, doing more than a single set would seem to be most effective.
If you take the approach that you’re pressed for time and can only do a single set of each exercise, make sure you’re lifting at a high percentage of your one-rep max and taking the set to failure or near-failure. When you’re only doing a single set, you have to push harder than you normally would.
The Bottom Line
Despite the time-saving convenience of doing a single set of each exercise when you train, you’ll likely achieve more gains in strength and muscle size if you do 3 sets, although a few studies show no difference in gains between 1 and 3 sets. Even if you stick with 3 sets during most training sessions, you can use a single set to vary your workout or as a fallback when you’re short on workout time. Just remember, you won’t get anywhere if you do a single set that doesn’t challenge you. What you’re sacrificing in volume, you have to make up for with intensity.
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Journal of Strength and Conditioning Research 2007 Feb;21(1):157-63.
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