Today, we'll be having a look at James Krieger's The Volume Bible to find the most up to date evidence on how much volume is ideal for hypertrophy.
James Krieger is a published scientist, author, and speaker in the field of exercise and nutrition. He holds a Master's degree in Nutrition and a second Master's degree in Exercise Science and has published numerous studies in the field. He also runs a research review, Weightology, in which he reviews the latest research in the field of exercise science, which is where I obtained his holy scriptures. This "bible" is a whopping 61 pages chock full of studies, graphs, tables meta-analyses and his own conclusions. If you're brave enough, you can check it out for yourself here: link or, instead, you could read this short article to find out all you need to know about how much work you need to do to see muscle growth.
Before I begin, let me provide some definitions so we're both on the same page.
Volume is a measurement of how much work you do, usually measured by the weight, reps and sets you perform.
Hypertrophy is muscle growth, which is ideal for people aiming to put on size, lose fat or just look their best.
Here is the TL;DR version:
On average, muscle growth tends to be best around 6-8 hard sets per muscle group per training session when taking long rests. That can be 12 - 24 weekly sets for a frequency of 2-3 days per week.
Volume needs may be double this when taking short rests, but the max muscle growth is still around the same so there's no advantage to doing short rests.
Individual results may vary substantially from these averages, with some individuals having volume ceilings much higher than 8 sets per session or 24 weekly sets.
Volume increases are best done in small (20%) increments.
So let's break that down a bit.
6-8 hard sets per muscle group, per training session
Per muscle group refers to the primary movers in a lift. For example, in a bench press you are using your pec major (chest) muscles but you are also using your triceps to push the bar away from you. If you do 4 sets of bench press, then 2 sets of another exercise called tricep extensions, your triceps muscle group will have performed 6 sets of volume, while your pecs will have performed 4 sets. Hard sets mean the set must come close to failure (or technical breakdown), regardless of the weight being used (heavy weights require less reps to get to failure, whereas light weights require more reps).
Volume needs may be double this when taking short rests
When we take longer rest periods (2+ minutes), we are able to work our muscles to a greater extent before fatiguing. Taking short rests (<90 seconds) may seem like you're working harder, but you're not creating the same stimulus to the muscles, which is why, to get similar results, the number of sets must increase around double the amount needed for long rests. Oftentimes, females are the ones taking shorter rests (because they don't want the heavy weights to make them bulky... 🤦♀️) which means they will have to perform more sets to see similar benefits. Don't make things harder for yourself, work hard for your set, then get some rest.
Individual results may vary substantially
It is important to remember that these are just averages. Individuals have been reported benefiting from up to 15 hard sets per muscle group, per session or 30+ sets per week. Of course, the same applies in the opposite direction, not everyone needs to hit 8 sets per session to see muscle growth. These numbers should be used as a guide to find optimal muscle hypertrophy, not as a text to be followed religiously (despite having the word bible in the title).
Volume increases are best done in small (20%) increments
When increasing volume, it is best done in a progressive manner rather than starting everyone at the ideal number. This is to take into account previous training history and to avoid overtraining. The volume bible provides this step by step process for building up to high volume programs:
Begin with a low training volume (for example, 2-3 sets per muscle group or 4-6 weekly sets).
Add sets per muscle group or per exercise over time (such as once per week, or per session as long as you don't experience next-day soreness). Research suggests a 20% increase in set volume is appropriate.
Continue adding sets until you hit a plateau.
If two successive 20% increases in volume fail to stimulate further progress, then you've likely hit a plateau and would benefit from changing up your program for a new stimulus.
Other key take aways
No matter what the well-studied average says, the best results come when individualisation is accounted for. This means that if someone is not recovering enough between sessions, decreasing the volume below the minimum number of sets stated here can be beneficial or if someone is already performing the maximum number of sets, they may still find benefits in increasing that volume further. These numbers are the averages and there were multiple outliers in the data.
This research review is aimed at finding the ideal volume for muscle growth. Keep in mind that anything is better than nothing, so don't worry if you aren't quite hitting the minimum numbers, you can still experience significant muscle hypertrophy (especially if you're a beginner) and not everyone prioritises speed of muscle growth.
The research suggests that the typical "bro-split" of blasting one muscle group for very high volume per session (e.g. having a leg day, a back day and a chest day) may be inferior for gaining muscle. It appears better to split the volume up into 2-3 sessions per week.
So, when aiming for muscular hypertrophy, the latest research suggests...
Hit 6-8 hard sets per muscle group, per session for around 12-24 sets per week.
Take plenty of rest or increase your volume substantially.
Increase your volume incrementally (about 20% at a time).
Individual results may vary. Make sure your program is working for you.
Hopefully this article gave you some professional pointers without requiring a master's degree in the field. If you found something useful don't forget to sign up to my mailing list below and check out more of James Krieger at https://weightology.net/ or on his instagram account here