Building muscle can help improve strength, reverse the effects of age-related muscle loss, and, in some cases, improve sport performance. Expectations of what levels of hypertrophy are attainable can be useful for long-term goal setting and may help encourage a realistic body image.
How Much Muscle?
Without advanced equipment, determining fat free mass can help estimate how much muscle an individual carries. Fat-free mass includes all of our body’s components, excepting fat. It is assumed an individual with greater fat-free mass also possesses greater muscle mass.
In studies related to body composition, researchers sometimes use a calculation to determine how much fat-free mass participants have in relation to height. This is a relatively simple calculation involving height, weight, and percentage of body-fat. The link below makes the calculation process very easy.
Fat-Free Mass Index of a Reference Population.
Once the FFMI has been determined, it may be useful to compare this number to a “normal” healthy population. This comparison may help give a realistic perspective on how much fat-free mass people carry.
What does the fat-free mass index of a normal healthy population look like? The following is data gathered by Schutz et al. (2002) and sampled from a healthy Caucasian population of over 1,000 people.
Men (FFMI kg/m2)
18-35 y/o 16.8 17.2 18.0 18.9 19.8 20.5 21.1
35-54 y/o 17.2 17.6 18.3 19.2 20.1 21.1 21.7
Women (FFMI kg/m2)
18-35 y/o 13.8 14.1 14.7 15.4 16.2 17.1 17.6
35-54 y/o 14.4 14.7 15.3 15.9 16.7 17.5 18.0
Notice that it is unusual for men in the average population to have a FFMI greater than 22 and women to have a FFMI greater than 18.
What do these numbers mean?
Gruber et al. (2000) proposed the following:
- 18 – slight build with low musculature
- 20 – average musculature
- 22 – distinctly muscular
- >22 – not normally achieved without weight training
- 25 – the upper limit of muscularity without pharmacological agents (e.g., anabolic steroids)
- 13 – low musculature
- 15 – average musculature
- 17 – distinctly muscular
- 22 – not typically achieved without pharmacological agents (e.g., anabolic steroids)
The above information should help give the resistance trainer perspective on how muscular they currently are and what research suggests is the upper level of muscularity. A FFMI greater than 25 for men and 22 for women may be achieved without pharmacological help but this does not seem to be common.
Genetics, environment and training play a crucial role in how muscular an individual can become. In my experience, a FFMI of 22-25 is attainable for many men with reasonable levels of bodyfat after several years of weight training. Keep in mind that the work by Kouri et al., which determined the upper level FFMI (25) for men did not include subjects with body fat greater than 20%. Those with increased body fatness (>20%) may be able to exceed a FFMI of 25 through mechanisms such as increased organ size, visceral fat, intramuscular fat (Kouri et al. used calipers which do not directly account for visceral or intramuscular fat), or even increased musculature.
I believe a FFMI of 17-20 is attainable for many women after several years of weight training. Gruber et al. (2000) believe that a FFMI of 22 is the upper limit for women.
- Knowing the FFMI of a “normal” population may help encourage a realistic body image.
- Understanding of what researchers believe to be the upper limit of muscularity without pharmacological assistance should give an idea of what can be achieved and what may not be easily attainable.