Does Physiological Training Matter for Special Ops?

BUD/S candidates learn teamwork by carrying 600-pound log.
First Phase Basic Underwater Demolition/SEAL candidates use teamwork to perform physical training exercises with a 600-pound log at Naval Amphibious Base Coronado. (Petty Officer 2nd Class Shauntae Hinkle-Lymas/U.S. Navy photo)

If there is a perfect ratio of physiological gifts or training to develop fast-twitch and slow-twitch muscle fibers for tactical athletes seeking special-ops selection, I am not aware of it. Getting good at all the elements of fitness that apply specifically to your selection program is critical to success.

The rules and phases of tactical fitness do not change for those athletes. In the end, success is more about the internal will to succeed than a student's particular physiological makeup.

Here is a question that opens a great discussion on the topic of physiology, psychology and even academic abilities to be successful in high-attrition selection programs:

Could there be something physiological making BUD/S more doable for some than others? Maybe a certain ratio of slow-twitch to fast-twitch muscle fibers? Or is it really 100% mental? If it is mental, what mental training does one need to make the physical happen? I appreciate your time, sir, and I look forward to your reply.

That is a great question. I have seen people with a history of strength training who worked to be better runners and swimmers do really well getting to and through Basic Underwater Demolition/SEAL training. And I've also seen endurance athletes work to get stronger and then do really well. But I've also seen failures among above-average athletes who otherwise function on a collegiate, professional or Olympic level.

I wish there was a physiological answer for success at BUD/S or any other selection, but it is so challenging that it becomes more of a battle between your body and mind. Passing boils down more to your internal will than physical attributes.

That said, a foundation of strength is still most important, followed by turning into a better endurance athlete. You also can do the opposite, coming from an endurance athlete background and getting stronger.

But in very basic terms, lifters need to be better runners and swimmers, and swimmers and runners need to become better lifters. That is what the candidate tactical athlete has to prepare to do -- be good at all the events tested. Tactical fitness applies to any profession in special ops, military, police and fire fighting -- just at different levels of the fitness spectrum.

Mental or academic ability?

Math, science and English do have their place in BUD/S, with a steep learning curve of navigation, diving and shooting. But when we say that the training is "10% physical and 90% mental," we're talking about mental toughness, not academic ability.

To meet and exceed the standards for getting in and staying in training, there is obviously a base of physical ability required. But to endure the pain and discomfort of each day, one must be prepared mentally for being uncomfortable and handle it without thought. Your work capacity and durability play a major part in success, and the only way to get that is to spend significant time preparing to get to and through the training.

Some basic physiology to help explain your question/answer

Physiologically speaking, maybe there is something that makes a successful BUD/S student, but it has not been proven precisely. Many studies and statistical analyses have been done at BUD/S on students who were and were not successful. You can look at the official Navy SEAL + SWCC website to see the Speed, Distances and Reps that Correlate with Hell Week Success article to get an idea of some of the objective scores that help with Hell Week success.

Here's a closer look at exactly what we are talking about when we discuss physiological makeup:

Type 1 muscle fibers. Also known as "slow-twitch fibers," these skeletal muscle types are dense with capillaries, with a very high capacity for using oxygen and body-fat breakdown for energy. These also are considered aerobic and are associated with a lower heart rate and help with longer endurance.

Type 2a muscle fibers. Also known as "fast-twitch fibers," these are also dense in capillaries. They can utilize the body's storage of glycogen and blood sugar for higher-intensity energy needs, such as fast-paced, high-repetition calisthenics, running and swimming at medium distances.

Type 2b muscle fibers. Also known as "super-fast twitch fibers," these are designed specifically for anaerobic energy consumption for activities like heavy lifting and sprinting.

When we are born, we have a certain percentage of slow- and fast-twitch fibers. Some studies have shown that, through challenging training programs, you can convert muscle fibers within the Type 2a and Type 2b groups, but you cannot change Type 1 into Type 2 or vice versa.

Still, through six to 12 months of training, a strength athlete can become a better and faster runner or swimmer, and an endurance athlete can become a stronger athlete and improve calisthenics and weightlifting maximum strength and power performance. That happens as they convert a certain percentage of Type 2a and Type 2b fibers to handle the stimuli they're exposed to in training better. Check out this study on Type 2 to Type 1 possibilities.

For the tactical athlete, the three muscle types must be developed adequately. All three types of muscle fibers are important to any athlete and will be enhanced by the specific training provided. For the tactical athlete, the muscle fibers work together to create an athlete with more durability and work capacity.

I would not get too caught up with what constitutes a better percentage of Type 1 or Type 2 fibers. Just get out there and do it, and stay there because you really want to serve in that capacity. Training is designed to test your why.

Stew Smith is a former Navy SEAL and fitness author certified as a Strength and Conditioning Specialist (CSCS) with the National Strength and Conditioning Association. Visit his Fitness eBook store if you’re looking to start a workout program to create a healthy lifestyle. Send your fitness questions to

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