Guys hitting the gym are always looking for the best training program or supplement that’s going to enhance their performance and unleash those hidden gains. This often leads into a question of “what’s the best training split?”, which is almost always following by a very heated discussion among bros about which split is superior.
Test this for yourself. Just walk up to any number of guys (or girls) at the gym and ask them what split they think is best. Chances are you’ll get as many different responses as the number of people you asked.
So, rather than get another bro-pinion on the question, let’s take a look at what the research has to say, and see if we can finally answer once and for all what the best split for muscle growth is.
The “Best” Training Split
Given how hotly debated this topic is, there’s a surprising lack of research regarding the topic. First off, there is no study that clearly defines the “best” or “most optimal” training split for individuals. There’s simply too many variables to account for (reps, weights, time under tension) to accurately answer this question. Nevermind the fact that each individual has a unique makeup of muscle fibers and recovery abilities, so before going any further, just know that there is no one single “best” training schedule for all human beings on planet earth.
Sorry to disappoint you.
That being said, there have been a handful and studies, reviews, and meta-analyses that have unearthed a few crucial nuggets that can help you come up with the best training schedule based on YOUR abilities.
Optimal Training Research
One thing that is clear from the limited research done on muscle hypertrophy is that there is a dose-dependent response to training. In other words, higher volume protocols are associated with greater increases in muscle size. A systematic review and meta-analysis of the available literature led by “The Hypertrophy Doc” Brad Schoenfeld showed that higher volume protocols (>9 sets / muscle group per week) provided greater increases in hypertrophy than low (
Does that mean you should be doing 20+ sets for each muscle group each workout? No, natural athletes lack the ability to recover sufficiently from excessive workloads, not to mention the CNS fatigue that also accumulates over a week of heavy lifting.
The “sweet spot” seems to be 10+ sets per muscle group, but the upper limit on sets will ultimately be governed by an individual’s ability to recovery. It’s best advised to start on the lower range and increase if your performance is not increasing with the 10 sets per muscle group per week.
In regards to training 1x, 2x, or 3x per week for a muscle group, there hasn’t been an ideal frequency identified in the literature. Research on resistance-trained individuals demonstrates an advantage to training muscle groups more frequently (3x vs 1x per week) with volume equated, but very high frequency (6x vs 3x per week) has been shown to provide no additional advantage. And in novices, frequency isn’t always associated with better gains.[5,6]
Another meta-analysis by Schoenfeld & Co. shed some light on the frequency debate in that it showed that training a muscle group 2x / week resulted in better gains than training it 1x / week, but didn’t discuss training 3x / week:
“It can therefore be inferred that the major muscle groups should be trained at least twice a week to maximize muscle growth; whether training a muscle group three times per week is superior to a twice-per-week protocol remains to be determined.”
A study is currently underway led by none other than Brad Schoenfeld which will compare muscular adaptations to a training frequency of full-body 3x / week training vs a 2x / week upper/lower split for each muscle group with volume equated weekly. Hopefully the results of this study will continue to shed some light in determining once and for all the best workout schedule.
Intensity refers to lifting heavy weights or light weights. Yet again, Schoenfeld and his team have sought to answer this question which is constantly debated by trainers -- heavy weight for low reps or lighter weight for higher reps to spark hypertrophy.
Well, the good doc has conclusively shown that hypertrophy can occur when training with very low reps (8-12 reps / set) and with very high reps (25-35 reps / set). Provided you take a muscle to failure, and employing progressive overload, you can increase muscle size using a variety of rep ranges.
The final variable we’ll address is “how long should you rest between sets.” You’ll often hear that for hypertrophy you should rest 45-90 seconds and for strength rest 3-5 minutes. Well, Schoenfeld has looked into that to, and the answer might surprise you.
When tracking rest intervals and their impact on hypertrophy, Schoenfeld and his team found superior gains in muscle size when subjects rested 3 minutes vs 1 minute. Both groups did experience gains in size, but the 3 minute rest interval group increased strength and size greater than the 1 minute interval group.
So, for those larger muscle groups (legs, back, chest), it might pay some extra dividends to take an extra second or two between sets to gather yourself and push that much harder the following set.
So, what are some of the key takeaways we can gather from all of this:
10 sets per week seems to be the minimum number of sets per muscle group to induce significant hypertrophic adaptations
Training more frequently is better than less frequent training sessions, but frequency is secondary to volume and intensity. If you aren’t doing an appropriate amount of volume or pushing your muscles to failure, it doesn’t matter how many times you hit a muscle per week.
Total weekly volume and one’s ability to recover from it is paramount to developing an effective hypertrophy training program and should be tailored to an individual’s abilities (i.e. one size doesn’t fit all)
Resting 2-3 min may yield superior gains for hypertrophy over the frequently recommended 1 min rest interval.
Let’s say your back is a weak point in your physique. How can you put the principles outlined above to work and shore up your weakness?
If you’re currently training each bodypart one time per week, consider adding in an extra back day to your schedule, or sprinkling in a few extra sets throughout the week in your other workouts to specifically address your back (preferably not on the days immediately before or after your back day).
Even though science has yet to identify one “best” way to train, there are several important findings which have been discussed that can help you craft your own specific “optimal” training schedule. Remember to hit your muscles with sufficient volume and intensity, while employing progressive overload, and you’ll be well on your way to creating the best training schedule for your body.
Schoenfeld B, Ogborn D, Krieger J. Dose-Response Relationship between Weekly Resistance Training Volume and Increases in Muscle Mass: A Systematic Review and Meta-Analysis.; 2016. doi:10.1080/02640414.2016.1210197.
Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Tiryaki-Sonmez G. Influence of Resistance Training Frequency on Muscular Adaptations in Well-Trained Men. J strength Cond Res. 2015;29(7):1821-1829. doi:10.1519/JSC.0000000000000970.
Schoenfeld BJ, Ogborn D, Krieger JW. Effects of Resistance Training Frequency on Measures of Muscle Hypertrophy: A Systematic Review and Meta-Analysis. Sport Med. 2016;46(11):1689-1697. doi:10.1007/s40279-016-0543-8.
Schoenfeld BJ, Peterson MD, Ogborn D, Contreras B, Sonmez GT. Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. J strength Cond Res. 2015;29(10):2954-2963. doi:10.1519/JSC.0000000000000958.
Gentil P, Fischer B, Martorelli AS, Lima RM, Bottaro M. Effects of equal-volume resistance training performed one or two times a week in upper body muscle size and strength of untrained young men. J Sports Med Phys Fitness. 2015;55(3):144-149.
Candow DG, Burke DG. Effect of short-term equal-volume resistance training with different workout frequency on muscle mass and strength in untrained men and women. J strength Cond Res. 2007;21(1):204-207. doi:10.1519/R-19785.1.
Schoenfeld B, Pope Z, M. Benik F, et al. Longer Inter-Set Rest Periods Enhance Muscle Strength and Hypertrophy in Resistance-Trained Men. Vol 30.; 2015. doi:10.1519/JSC.0000000000001272.