Find out the maximum amount of muscle you can build!

A question that comes up regularly on forums and is usually asked by beginners is along these lines: "What is my maximum potential for muscle gain?"

It should go without saying that no one can say in advance what anyone's genetic potential actually is. Furthermore, worrying about such things before you even start training usually misses the point completely. At a basic level, exercisers should train and eat correctly and just let what happens happen.

Expert Lyle McDonald has looked at this issue from different perspectives. Nevertheless, in most cases these lead to a relatively similar result, as we will see below.

The McDonald model

Lyle McDonald himself has used the following calculation for maximum muscle building potential in a number of articles and papers:

These are values for men. Women should use about half of these values.

Of course, these are average values. Some assumptions have been made about correct training, diet and the like. Age will also interact with these values - older people will not build muscle as quickly and younger people may build muscle faster. For example, it is not unusual for an underweight student to build muscle very quickly. However, these individuals usually start out severely underweight and just have a natural steroid cycle called puberty working for them.

The year of training refers to the years of proper training. Someone who has been training for 4 years and hasn't built much muscle could still have about the muscle building potential from year 1 if they start training properly.

If you now add up all these values, then you come to roughly 40 to 50 pounds (18 to 23 kilos) of total muscle mass over the course of a training career. Of course, it can take more than 4 years to achieve this. So if you started with 59 kilos of lean body mass, you may have the muscle building potential to reach a level of 77 to 82 kilos of lean body mass. With a body fat percentage of 12%, this would correspond to a total weight of 86 to 91 kilos.

Of course, these are only rough averages. You will certainly also see people who build up a little more and others who build up a little less

The Alan Aragon model

Alan Aragon has also looked into this topic. In his monthly Research Review column, he addressed the topic of rates of muscle gain in a different way, with quite similar results. He found that the following rates of muscle gain should be roughly achievable for natural (steroid-free) exercisers. However, it's important to note that this ignores things like creatine loading or temporary glycogen supercompensation, which can cause rapid changes in lean body mass that don't represent actual changes in skeletal muscle mass.

So a 150 pound (68 kilo) beginner might be able to gain 1.5 to 2.25 pounds of muscle per month (18 to 27 pounds per year). After a year, he's a slightly more advanced exerciser at 170 pounds (77 kilos) and might be able to build 0.85 to 1.7 pounds of muscle per month (10 to 20 pounds per year, with 20 pounds I'd consider exceptional gains). After another year, he is an advanced exerciser with a body weight of 180 pounds (82 kilos) and might be able to build only 0.5 to 1 pound of muscle per month (real muscle gains of one pound per month would be very rare for an advanced athlete).

He could peak at 190 to 200 pounds (86 to 91 kilos) or something along those lines after another year or two of training and have about 170 to 180 (77 to 82) pounds of lean body mass with a body fat percentage of 10%. This model comes to almost the same conclusion as my model, even though we took a slightly different path.

Casey Butt's Frame Size Model (Bone Structure Model)

Of course, both McDonald's model and Aragon's model for maximum muscle growth are greatly simplified and do not take into account some other factors. One of these factors that could influence the potential for strength and muscle growth is bone structure.

Casey Butt, a steroid-free bodybuilder, has done a thorough analysis of natural (steroid-free) top level bodybuilders and developed a calculator that predicts maximum muscle building potential. This involves looking at body size, wrist and ankle circumference in conjunction with a target body fat percentage.

Lyle McDonald then ran an exerciser with a wrist circumference of 7" (17.8 cm) and an ankle circumference of 8.5" (21.6 cm) and different body sizes through this calculator to show the predicted body weights (at a body fat percentage of 10%) and lean body mass.

As you can see, Casey's calculations are somewhat more conservative than those of McDonal or Aragon. Nevertheless, his values are at least close to the other values. Some may argue that bone structure has nothing to do with all this. In fact, there are scientific studies that support this idea.

Bone structure as a decisive factor?

At least one study showed that people with a lighter bone structure built less muscle when using the same exercise program compared to people with a heavier bone structure, and at a more basic level, hormones like testosterone also affect things like bone growth and bone structure. So there is a potential biological link between bone structure and hormone levels. This can contribute to training ability and ultimately to gains in muscle mass.

It is also no coincidence that the best strength athletes typically have a heavier bone structure and robust joints. Some of this is simply due to their ability to cope with the level of training required to be successful at their sport, but some of it is probably also indicative of overall hormonal status.

Martin Berkhan's muscle building model

Martin Berkhan has a slightly simpler model than Casey, which is also based on his observations of natural top level bodybuilding competitors who are in competition shape.

His equation is as follows:

Height in centimeters - 100 = upper limit for bodyweight in contest shape

So you subtract 100 from the height in centimeters to get the predicted maximum body weight in competition form. Let's look at the body weight at a body fat percentage and use the same body sizes as in Casey's calculations.

Even if these values are not identical, they are in the same direction as the values from Casesy's calculator. However, it should be noted that bodybuilders in competition form are often severely dehydrated. In addition, glycogen stores are usually depleted. This tends to lower the measured lean body mass. We could realistically add 5 to 10 pounds of lean body mass to the values above to account for dehydration. With this adjustment, the values are more or less identical to Casey's values.