The Myth of Bulk: Why Women Should do Crossfit

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There is a particularly popular YouTube video series that comes to mind when you hear some women speak about why they don’t do Crossfit or any type of heavy Olympic lifting. The series is aptly titled “Sh*t (insert some sport or activity or group here) Say.” Some of the Sh*t I hear anti-crossfit women, and even some pro-crossfit women, say goes as follows:

  • “I don’t want to get bulky arms/legs/back/etc.”
  • “I don’t want to get too BIG.”
  • “I don’t want my thighs to get bigger.”
  • “I don’t want to look like a body builder.”
  • “Is that Jason Khalipa?!?”

I think you’ll have noticed a theme by now. Without dancing around the issue let me make a proclamation: Doing Crossfit with [relatively] heavy weights will NOT make you look like a body builder.  Moreover, the advantages of doing crossfit-type training far outweigh any perceived disadvantages.


I don’t really need to remind any readers of this blog that I’m not a doctor. However, I have researched the topic thoroughly and gotten feedback from an actual physician. The information is yours to absorb or not, hopefully (if nothing else) it inspires some enlightening debate in the gym.

I realize that claiming you “will NOT…look like a body builder” doing crossfit is painting in broad strokes. Dr. Fredrick C. Hatfield, a world champion powerlifter and sports science PhD, coined the term The Principal of Individual Differences. As you can likely deduce from the name, everyone in this world is different (no sh*t). From a physiological perspective this means that one person’s response to this type of training will be quite different than another person’s over a range of factors. In the proceeding section I will attempt to explain myself without boring you to tears.

The Layman’s Explanation of Body Types


One large determiner of how you look after doing a certain type of workout depends on your body type or, more scientifically, your somatotype. Somatotypes are defined as follows:

  • Ectomorph: Thin, light bone structure, difficult to gain mass.
  • Mesomorph: Muscular, lean, gains muscle mass relatively easy.
  • Endomorph: Heavy, large bone structure, likely to gain weight (either through muscle or fat).

To further complicate matters it is rare that someone is completely one somatotype. Typically people are a combination of all three types, perhaps with one dominating over the rest. Thus, your propensity to get bigger or “look like a bodybuilder” is more than a little dependent on your genetics.

Moreover, it’s important to distinguish between mass and strength. Mass, as the title implies, is the size of your muscles. Strength, on the other hand, is the person’s (or muscle’s) ability to bear weight and/or provide resistance to external stimuli. Although the two are correlated, they aren’t the same thing. Someone with huge muscles may not be able to lift as much weight as a “flabby” powerlifter with poor aesthetic genetics.

Heavy and Short or Light and Long?

Bearing the above differences in mind, and understanding that there is no “one formula” for everyone, what is the proper rep and weight scheme to avoid gaining muscle mass? I have heard from several women that they avoid doing heavy weight during certain exercises because they don’t want to get big – and instead they focus on a low weight/high rep combination.

The body’s adaptive response to working out is called muscular hypertrophy. At the most basic level hypertrophy simply means the enlargement of a muscle fiber. Hypertrophy will vary based on your body type (as mentioned above) and the composition of fast-twitch and slow-twitch muscle fibers in your skeletal muscles. It sucks, but both of those things are out of your control. In general, however, there is nearly a consensus in the body building world as to what leads to bigger muscles (aside from genetic composition).

Pay attention ladies, this is where I try to make a point after a couple paragraphs of ranting. The abovementioned consensus is that in order to gain mass it is best to work at a “sub-maximal” weight for several reps (8-12+). This leads to sarcoplasmic hypertrophy which tends to lead to bigger size gains – and not necessarily comparable strength gains. What this means is that working at a weight well below your maximum for a certain exercise for a “large” number of reps is actually making you bigger! In contrast, in order to gain strength (and this theory is supported by many power and Olympic lifting programs throughout the world) it is best to use a weight at or near your max for a short number of reps (2-8). This leads to myofibrillated hypertrophy which increases muscle strength more than mass. Additionally, training heavy weights for a short number of reps engages the fast twitch fibers and makes you more powerful – but not necessarily bigger. Mark Sisson has a good article here if you want to read more on this theory.

Further Benefits

In Crossfit, or a similar exercise program, the increased muscular activity will also increase your body’s metabolism. When you have a more powerful engine, it often requires more fuel to keep it running (remember to eat Paleo). An increased metabolism over  a sustained period usually leads to a very lean frame.

Because Crossfit focuses on what is called “functional” fitness you’re making it easier on yourself to perform everyday tasks. Although some of the things we do seem far removed from the realities of everyday life (admittedly I don’t often do hand stands or box jumps at any point during my work day) you’re training muscles that you use on a daily basis. Further, for those concerned with health and longevity, some anecdotal evidence suggests that Crossfit can help you age more gracefully.

You’re also improving cardiovascular fitness. Although slogging it out on a treadmill seems to be some folks’ ideal “cardio” workout, there are substantial benefits to cardiac health in doing Crossfit. Moreover, the high intensity interval training (HIIT) favored by crossfit is alleged to burn more fat and make people more (you guessed it) lean.

The range of exercises done in Crossfit also increases strength in several muscle groups (as opposed to single muscle “isolation” exercises). Thus engaging your core to balance yourself during overhead squats is probably benefitting your abs as much as those 1,000 crunches you used to bust out weekly during the “bikini season.” And as a bonus the constant variation of crossfit means you likely won’t get bored at the gym.

And in Conclusion…

The “optimum” exercise regimen for a particular person will depend on several different things – chief among them is the genes their parents gave them. However, ladies if you’re trying to avoid size by doing light weights and high reps – you’re going about it the wrong way.

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