09/29/2026
In tactical fitness, CSS stands for the Combat Swimmer Stroke, a modified sidestroke popularized by former Navy SEAL and tactical fitness coach Stew Smith https://www.stewsmithfitness.com
It serves as the signature swimming technique used by candidates trying to get into Navy SEAL, SWCC, EOD, and Fleet Diver programs. Here is the perfect CSS the way Stew Smith teaches it -
https://youtube.com/shorts/i5cG4CXXrc4?si=EWcmhRzAKfgAL3RB
Key Characteristics of the CSS
• Efficiency & Energy Conservation: The stroke combines elements of the traditional sidestroke, freestyle, and breaststroke. It is highly efficient, allowing special operations candidates to save their energy for subsequent physical tests (like pushups, situps, pullups, and running).
• Underwater Recovery: Unlike freestyle, where arms exit the water, the CSS requires an "underwater recovery" where the arms stay below the surface. This is mandatory for passing the official Navy Physical Screening Test (PST). Learn how to ace the PST here: https://www.stewsmithfitness.com/products/book-so-navy-seal-workout-phase-1
• Stealth: By keeping a low profile and eliminating surface splashes, the stroke minimizes detection during night or open-water tactical operations.
https://www.stewsmithfitness.com/blogs/news/spec-ops-use-of-the-combat-swimmer-side-stroke-css-explained
• The "Magic" Sequence: Stew Smith famously trains athletes to master a strict, rhythmic tempo: Pull → Breathe → Kick → Glide. Swimmers are taught to hold a streamlined glide for 2 to 3 seconds on every stroke to maximize horizontal distance per movement. See more here in article/video format: https://www.stewsmithfitness.com/blogs/news/pull-breathe-kick-glide-1-mississippi-2-mississippi-repeat
Smith heavily features the CSS across his instructional platforms, offering online coaching, books, and regular video critiques on YouTube and Instagram to help non-swimming athletes master the technique for Special Ops jobs in their future.
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