A popular and somewhat controversial topic among fitness experts and scientists alike. Before we delve too deep, a “split” is just the sequence or day of the week you perform you exercises in. There is the classic “bro split” which usually details a single body part per day. The upper/lower split in which you work out muscle groups from your upper body on one day and the lower body on another (usually hitting the same body part more than once a week). Push/pull splits where you are working out your pushing muscles one day and pulling on another (also usually hitting the same body part multiple times a day). There is also those that enjoy a full body workout whenever they workout. Each workout split has its own advantages and disadvantages from a timing and scientific standpoint.
The first split we will talk about is the classic “bro split“. Not going to lie, I love this split. Despite all the claims that it is just “bro science” and all the negativity behind the word “bro” these days, it still works. I like it because I get to take my weekends off and focus on my family, friends and sanity. I like really targeting a single muscle group a day and killing it. I love the pump I get in that muscle group when I leave the gym. Despite all of this, I will be honest in saying that the research shows that this is not the OPTIMAL split to build muscle. The reason for this is you are not stimulating the muscle group as frequently as you OPTIMALLY should be. This split is generally divided into 4-5 days with specific focus on chest, back, legs, arms and possible a dedicated shoulder day (with abdominal exercises generally sprinkled in, but some sprinkle in shoulders AND abs and take an additional rest day).
The upper/lower split is a promising split. With this split you are simply focusing on upper body muscle groups one day and lower body (legs) on another. This will target all of your muscle groups multiple times a week if done right. You can do this split 4 times a week up to 6 times a week. The only problem I have with this system is that a vast majority of your muscles are in your upper body (well the muscles we generally focus on at least). This can lead to overtraining of your legs and undertraining of the upper body muscle groups. I personally feel like this split doesn’t allow you the time to focus on all the upper body muscles with the proper volume to stimulate growth unless you spend quite a bit of time in the gym on upper body days. I will touch on volume after I go through the splits.
The Push/pull split is similar to upper/lower because you can do it 4-6 times per week and it hits muscle groups multiple times throughout the week when done right. I feel like this, however, promotes a better balance between upper and lower body muscle groups. Unlike the upper/lower body splits there is not as drastic of a difference between the amount of trainable muscles in the front vs backside of your body when compared to your upper and lower body. You also have the added benefit of moving some exercises around that don’t really fit into either category well. For instance, you could do lateral deltoid training on either day as this isn’t a definitive push or pull exercise. In my personal opinion this is likely the OPTIMAL split for maximizing your muscle growth.
The full body split (or total body workout = TBW) is not really a split. You basically go to the gym multiple times a week and target every muscle group you can think of. Obviously this can be a very good workout, but most people find it too taxing to do this every day they workout and usually drastically extends your time in the gym to over an hour (most people I know that do a good total body workout are in the gym for about 2 hours or more). TBWs can also lead to more overtraining than other splits. I have personally seen many crossfit members (both new and seasoned members) in the hospital for rhabdomyolysis (severe muscle breakdown that can hurt your kidneys and other organs). TBWs are not for the faint of heart, nor would I recommend them for beginners. See below for more information on the proper volume of your workouts and how to prevent overtraining or muscle breakdown.
As long as you adhere to proper training volume you should be making progress (assuming all other factors of lean mass gaining are being addressed properly, such as diet and nutrition). To put it simply, volume (in this case) is expressed as working sets (excludes any warm-up sets) per body part per week (sets/body part/week). These sets should be done at around 60-85% of your one-rep-max (ORM). ORM is simply the weight at which you can only do one repetition with perfect form. I don’t expect everyone to know their ORM, in fact, I don’t even know mine. Most of the time finding your ORM requires you to lift very heavy weight. This can put you at high risk for injury and I don’t recommend doing it (or at least not often). If you are a strength competitor or someone who really strives to increase their ORM then that is a different story and you likely don’t need my advice on it.
The one caveat to volume is frequency. As mentioned in the bro split paragraph, you should optimally divide these sets up into at least twice a week to maximize muscle stimulation because some studies show that going a week between stimulation of the muscle group is not optimal for muscle growth, thus the downfall of the bro split. However, once a week still WORKS as long as the volume is there. Research shows that the optimal volume for building muscle seems to be in the 10-20 sets per body part per week zone. In order to maintain your current muscle mass most studies and experts agree that around 10 sets per body part per week is required. Many can tolerate much more than this (high volume training), but the hard part is that research has not yet landed on where you start getting into muscle breakdown from overtraining (and this point is different for everyone and also depends on your level of training). New studies have shown that there was no evidence of breakdown (overtraining) in up to 30 sets per body part per week, but they did not test higher than that. The point of overtraining is obviously very dependent on your current level of fitness. If you are just starting out, aim for the lower end of this spectrum to avoid overtraining and build up more volume over time. The more experienced you become, the more volume you can add (to a certain point – overtraining). Once you have settled in a good volume you should focus more on progressive overload than increasing your volume (especially if you are in the 20-30 set volume range already because you are stepping into risky and unknown territory as far as overtraining).
Once again, they key to all of this comes down to sustainability. If you know that push/pull or upper/lower splits are optimal for muscle growth, but hate that split, you likely aren’t going to stick with it or put in maximal effort. You need to find splits and exercises you enjoy doing and that fit into your schedule. I know that seems like an oxymoron to those new to working out, but you will eventually fall in love with certain exercises. Don’t let yourself slip into monotony however. If you keep doing the same exercises, the same way, with the same weight you will likely plateau. You need to find ways to mix it up, some of which I have discussed already in previous articles. Another way to mix it up besides methods I have mentioned in previous articles is to switch up your splits. This shocks the muscle quite a bit and is a way to test out new splits at the same time. A friend of mine (who I have mentioned in previous articles as the “beast-man”) switches up his splits every couple of months or so. He will cycle through various splits and even total body workouts. Muscle growth can be finicky so you need to “trick” or “shock” the muscle from time to time in order to continue growing. If your workouts gets stale, even if you are progressively overloading, your muscle growth with slow or stall.
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