March 21, 2026
Evidence-Based Strength Training, Part I:
What is a Training Split?
One of, if not the first consideration when designing a training program is which training split you will utilize. A training split is simply how the “work” (Volume, i.e. Sets, Reps, etc.) for major muscle groups is distributed across a training block, usually a period of a week. There is no universal “best split”, rather there are splits that are good for some and not as great for others, depending on constraints like sessions/week, time per session, or experience level/recovery ability. For the purposes of this blog, I will describe four commonly used training splits, their strengths and weaknesses, the rationale behind them, who they are best for, and my overall recommendations. The four splits we’ll discuss are: Full Body, Upper/Lower, Push/Pull/Legs, and the infamous “Bro Split”.
The Split Spectrum
I like to think about these splits lying on a spectrum. At one end of the spectrum, you have the variable of Frequency; the number of times per week that each muscle group is trained. At the other end of the spectrum, there are two variables: Volume and Exercise Variation. Volume is the amount of “work” done for each major muscle group. It can be defined as the combination of Sets x Reps, but in this context, it refers simply to the number of Sets done for each muscle group within each week block. Exercise Variation, which can often come along with additional Volume in this context, is the number of different exercises performed for each muscle group within the week.
Generally speaking, when it comes to Frequency, training each major muscle group as close to 2 x per week as possible is ideal for most people. Volume requirements vary widely by individual and by specific muscle group, but ~ 4–20 Sets per week for each major muscle group is considered ideal. With Exercise Variation, there is no hard and fast rule, but it is generally better to get as much variation as reasonably possible, especially with the more complex muscle groups like the back musculature.
Full Body
If you were to plot the four splits mentioned above on the spectrum of Frequency → Volume/Variation, the Full Body split where you train each major muscle group every session lies on the far end towards Frequency. If you train three times per week, then you would have a 3 x Frequency, and to cross the 2 x optimal threshold, it only takes two sessions per week. This makes it an ideal split for individuals with extremely limited time or who are highly untrained and require less overall Volume. The drawbacks of the Full Body split are that the overall Volume and Variation for each muscle are low unless each session is extremely long. This makes it not ideal for those with more than two days per week available to train as well as those with more experience and a higher recovery ability.
Upper/Lower
The Upper/Lower and Modified Upper/Lower split falls one step short of Full Body on Frequency, but one step higher on Volume and Variation. An Upper/Lower split simply means you train your entire upper body musculature on one day and then the next day you train, you focus on your entire lower body musculature and repeat with rest days as needed. If you train 2 x per week, then you at least train every major muscle once within that timeframe. If you train 4 x per week, then you are able to reach the optimal 2 x per week Frequency, and even if you can only make 3 x per week work, you still are left with a 1.5 x average Frequency with higher potential Volume and Variation without having to extend the time required each session. The Upper/Lower split is an amazing training split for those of all experience levels that have an average of 3–4 days per week to train.
Push/Pull/Legs
Moving one step farther on the spectrum away from Frequency and towards Volume/Variation lie three-day splits, the most common of which being Push/Pull/Legs. On Push Day, musculature that has the primary function of movement away from the body such as chest, shoulders, and triceps are trained. On Pull Day, musculature with the primary function of pulling towards the body such as the back, rear deltoids, and biceps are trained. The leg musculature is typically all trained on its own day, similar to an Upper/Lower Split. Push/Pull/Legs is a great split for those of all experience levels that train anywhere from 3–6 days. Frequency ranges from 1 x per week to 2 x per week depending on how many days you train. On average, this gives you less overall Frequency than Upper/Lower or any other split towards that end of the spectrum, but is also usually accompanied by a significant jump in Volume and Variation.
The “Bro Split”
The final split we’ll discuss is the famous (or infamous) “Bro Split”. This split generally entails dedicating each day to train an individual muscle or small groups of muscles. A common example would be something like: Monday – Chest, Tuesday – Back, Wednesday – Legs, Thursday – Shoulders, Friday – Arms. A split like this often works well enough for those on the far ends of the experience spectrum. Those who are younger and brand new to weight-training, as well as very advanced trainees whose strength can cause them to more easily exceed their recovery capability. Frequency with the “Bro Split” is low, rarely ever more than 1 x per week, but the Volume and Variation can be extremely high as you’re dedicating the entire session to training a single muscle or small group of muscles.
What Split is Best for You?
So, knowing all this, which split is best for you? As is the case with many things in life, the answer usually lies somewhere towards the middle. For most people, depending on your realistic number of training sessions per week, the Upper/Lower and Push/Pull/Legs split (or similar) provide the best balance of overall frequency, Volume, and Exercise variation. However, other splits definitely have their place. If you are rarely able to train more than once or twice per week, the Full Body Split is likely great for you, and if you fall into the category of brand new or wildly experienced trainee, the “Bro Split” might be fine.
For the vast majority of the weight training population reading this article, however, who are willing to dedicate 3–5 training sessions per week I would highly recommend one of the splits that balances the variables. Remember though, the best training split is the one you actually do! So, in the end, the most important factor might just be to follow the split that makes you enjoy training the most!
