By: Mike Caviston, Director of Fitness, Naval Special Warfare Center
Posted: August 5, 2020

The quality of the physical training and conditioning you do before Basic Underwater Demolition/SEAL (BUD/S) or Alpha Phase will greatly affect your odds of successfully completing selection and avoiding injury. By looking at results of physical fitness assessments performed by candidates before selection begins (administered at the Naval Special Warfare (NSW) Preparatory Course or during NSW Orientation), we can determine the relationships between run and swim times, push-up and sit-up reps, and other performances to outcomes such as drop on request, medical or performance roll, or successfully completing training. Simple statistics indicate which physical tests have the strongest relationships with completing selection and avoiding injury.

Run times have consistently shown the strongest correlation with success in BUD/S and Alpha Phase. Every enlisted candidate since BUD/S Class 270 has been timed for a 4-Mile Run at the NSW Prep Course, so thousands of data points show the relationship between running ability and the odds of getting through Hell Week. Swim times have also correlated well with success. Not only do run and swim times have more impact on success than other physical measures (e.g., strength), there is a direct link between speed and success: the faster candidates run or swim before beginning selection, the better the odds they will make it. Endurance is the most important fitness characteristic for success.

Why is endurance such an important factor? Here are some possible answers. During the first few weeks of BUD/S, candidates perform multiple high-intensity evolutions, each of which is difficult, but stacked back-to-back-to back become an ultra-marathon of physical performance. Running performance alone may not be a crucial factor (after all, the pre-Hell Week 4-Mile Run standard is 32:00, and being able to run in 25:00 doesn’t get you extra credit). But being able to run very fast on a test such as 4 Miles is an indicator of overall endurance that affects the ability to successfully complete all portions of the selection curriculum. Better endurance also allows the maintenance of better technique during fatiguing activities (such as Log PT), reducing the risk of injury. Perhaps training for endurance influences diet and nutrition in ways that favor success and avoiding injury.

The take-home message is to train seriously and aggressively because physical fitness has an enormous impact on success in the NSW selection process. However, it is crucial to understand which aspects of fitness are most relevant to success and to target them effectively. In short, train hard and smart. Prioritize running performance but follow the guidelines for increasing mileage and intensity in a systematic, progressive manner to improve running speed while minimizing the risk of injury. Follow a program with a blend of long slow distance runs and high-intensity intervals. Consult the Physical Training Guide (PTG) for details.


Naval Special Warfare Assessment Command