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Pacing is Key to Mastering Fitness tests and Becoming a Cardio Machine (Run, Ruck, Swim)

Stew smith ruck run spec ops triathlon swim

Learn the Difference Between Pacing, Sprinting, and Moving Aimlessly Without a Strategy

Run, Ruck, Swim

There's a trio of cardio activities that, when mastered, can dramatically improve your military readiness and endurance. We call is the Spec Ops Triathlon. This is not just a workout—it's a rite of passage for anyone serious about pushing their physical limits. This monthly evolution combines running, swimming with SCUBA fins, and a 50-pound ruck, borrowing straight from the grueling routines of military training and special forces selections. If lifting weights and doing calisthenics dominate your fitness regimen, it's time to make room for this multi-faceted cardio challenge. Want some inspiration? Check out #specopstri on Instagram for a gallery of motivation.

Run - Ruck - Swim Guidance: The Basics

Now, let’s talk specifics. Transitioning from a sports background to military training was no walk in the park. I hated running anything over 100 meters. If you share my sentiment, you’ll appreciate these nuggets from my 35-year journey of loathing running. See Running Plan to Get TO and THROUGH Training.

The same wisdom goes for rucking. It’s not just strapping on a heavy backpack and heading out—there’s a technique to master, which you can explore through my Rucking Progression Rules. Build up three paces with rucking: Walking pace at 15 minutes / mile. Power walking at 12-13 minutes / mile. And a short stride shuffle at the 10 minutes / mile pace. You may need all three for longer rucks in your training. Know the difference.

Swimming with fins, especially using the combat swimmer stroke, demands its own set of skills. Before diving in, ensure your technique, swim conditioning, ankle mobility, and hip strength are up to par. This preparation is non-negotiable. All require progressions that are logical (10-15% per week) and building aerobic base and pacing comfort. 

Avoid Injury: Become Better at Running By Not Overdoing It

Picture this: you’re training like a triathlete, but smarter. Building a solid cardio base doesn’t mean grinding through endless slow miles. Most non-running athletes face injury within weeks of over-committing to this method. Instead, think of running as just a third of your cardio routine. Fill the remaining two-thirds with low-impact activities like swimming, biking, rowing, or using the elliptical. Your hips knees, shins, and ankles will thank you - especially if you are a non-running - strength athlete on the bigger side (200+ lbs.). Build up to a 6 minute mile for shorter timed runs and 7 minute mile for longer timed runs.

Consider this approach: rather than jogging for an hour at a snail’s pace, push yourself with a 20-minute run at a challenging speed. Follow that with 40 minutes of steady-paced cardio through swimming or another non-impact cardio activity. You get an hour's worth of cardio with 1/3 of the impact. Your knees and shins will thank you, especially if you're new to longer-distance running. But, if you can handle a 5-8 mile long slow distance run, go for it. I am not saying you shouldn't do them, I am just sharing experience with non-running athletes using this method and ending up not able to run for months due to stress fractures, shin splints, tendonitis and other over-use injuries. Diversify your cardio when first starting down this longer running mileage per week journey.

Planning Your Cardio Week: A Structured Approach

Find your yard / second pace for both fins and no-fin CSS Workouts
(*Goal 50 yds / 50 seconds for both)

Here’s a sample schedule to integrate these cardio events seamlessly into your routine. This model borrows from various rigorous training programs, including the 50-50 Swim Workouts favored by Navy and Air Force, tread and drownproofing drills, as well as purpose-driven pace workouts and leg-day rucking.

 If you need to work on your cardio more than your strength, do your cardio first most days, however it is wise to do these events in the order of any fitness test or event you know is going to be part of any assessment. 


Leg Day



Leg Day

Sat or Sun

Warmup plus 1 mile timed

Repeat 8 times
400m @ GP
- 1 min walk

50-50 Swim Workout

Warmup with 500m swim
10 x 50m free + 50m CSS (minimum rest)

10 min tread no hands

Warmup plus 1 mile timed

Hills, beach, or bleachers 15 min
+ 2 miles of 1 min fast / 1 min easy

Ruck 2-3 miles (50lbs)
and / or
Swim 500m no fins warmup
Swim with fins 2000m for time
Tread 10 min with fins / no hands

Mobility Day
Repeat 5 times
5 min cardio
5 min foam roller, stretch, massage

Swim 10 min + Tread 10 min + drownproof workout

(add 50-50 if you prefer and need the conditioning)




Warmup plus 1 mile timed

Repeat 6 times
800m @ GP
- 2 min walk

50-50 Swim Workout
Warmup with 500m swim
10 x 50m free + 50m CSS (minimum rest)



2-3 mile run fast for time on beach, hills, if available

Ruck 2-3 miles but
-Do squat 20 / lunges 10/leg every 5 minutes of first 2 miles

Swim with fins 2000-3000m




Warmup plus

4 mile timed run

Optional – add in obstacle course if available for fun running

Add 50-50 if you need to conditioning






use bike, row, elliptical or more swimming in place of running if needed

use bike, row, elliptical or more swimming in place of run/ruck if needed

No running / rucking today any way - but add in more swim conditioning if needed

use bike, row, elliptical or more swimming in place of running if needed

use bike, row, elliptical o r more swimming in place of run/ruck if needed

use bike, row, elliptical or more swimming in place of running if needed

Add 10-15% distance / time per week to the above chart if you feel you can handle more cardio volume - otherwise keep the mileage the same and focus on make the runs / rucks / swims faster / easier to handle.

 = goal pace for timed runs (6 min mile) or 7 min mile for runs of 4-6 miles
Bike / Row - Replace any run / ruck with non-impact if volume is getting more than you are ready for until you progress to this number of miles per week
Leg Day - Top off leg day with Ruck or swim with fins (depending on your needs USMC, Navy, AF, Army, etc) 

Balance your cardio and strength training wisely. On most days, tackle your cardio first. But remember, if you’re preparing for an assessment, prioritize the events in the same order they appear in the test.

Follow these four pillars to morph into an endurance powerhouse:

1. Diversify your cardio activities, balancing running with swimming and other low-impact options.
2. Focus on running quality, not just quantity, to avoid injury.
3. Progress your rucking with a technique-first approach.
4. Integrate swimming drills to build comprehensive endurance.

Ready to up your game and become the ultimate cardio warrior? Dive deeper into the secrets of pacing and execution in the Spring/Summer Tactical Fitness Cycles. Visit the link and discover how to turn running, rucking, and swimming into your new strengths.

New Tactical Fitness Training Course!

Getting TO the training does not guarantee you get THROUGH the training. Learn about the two phases of tactical fitness you need to develop thoroughly before getting to BUDS. Check out the Online Course - Getting TO and THROUGH Special Ops Selection.

Who is Stew Smith? Coach, Trainer, Author, PodcasterI'm the former Navy SEAL that special ops candidates go to for books, ebooks and online coaching to prepare themselves to get to and through intense tactical assessment and selection programs and qualify for service in their chosen tactical profession.  See More at

Where to Find More Information About Optimal Performance Training Programs

When you start training again, consider the seasonal tactical fitness model.  I call it A WAY to train and obviously not the only way to train. But it offers the opportunity to never neglect your weaknesses, helps with flexibility and mobility, but will also put you at a level of physical abilities where you are happy with your overall ability to just about anything. We have a systems where the seasons dictate our training. When it is nicer outside, we tend to run and do more calisthenics.  When it is colder and not so nice, we lift more, run, less, and still maintain our outdoor activities with shorter runs and rucks. Check it out: Seasonal Tactical Fitness Periodization System.  

My most recent programs that walk you through these four cycles with 12 weeks of each season in two programs. 

These Seasonal Tactical Fitness BLOCK Periodization programs will walk you through 4 x 4 weeks cycles with 16 weeks of each season in two programs. (32 total weeks)

The Specific Military / Special Ops Physical Fitness Workouts Where Optimal Performance Will Be Tested Each Day

Navy SEAL Workout Phase 1
Navy SEAL Workout Phase 2 - 3
Navy SEAL Workout Phase 4  Grinder PT
Navy SWCC Workout

Army PFT Workout (Prep For Rucking, OPAT, ACFT)
Army Special Forces / Ranger Workout
Army Air Assault School Workout
Army Airborne Workout


Advanced Running Program - Special Ops Supplement Plan
USMC OCS / TBS Workout


The Combat Conditioning Workout
Air Force PJ / CCT Workout  Battlefield Airman Prep Course
The UBRR Upper Body Round Robin Workout / Spec Ops version


The Coast Guard Rescue Swimmer / Navy SAR Workout
The Service Academy Workout (West Point, Navy, Air Force Academy)
The Navy, Air Force, Marine Corp Boot Camp Workout


The Law Enforcement Physical Fitness Workouts

The FBI Academy Workout  |   FBI Workout Vol 2  
The DEA Workout
The FLETC Workout - Ace the PEB
The PFT Bible: Pushups, Sit-ups, 1.5 Mile Run
The Fire Fighter Workout - Ace the CPAT


Online Coaching Options

Online PT CLUB - Weekly Workouts created personally for you.

New Member's Only Content / Services Program!

If you want access to years worth of workouts, many of the top eBOOKs, favorite workouts of the week, free fitness APP, closed Facebook Group, video / picture library of exercises, and more access to LIVE Q/A sessions check out the Stew Smith Fitness Members Section

The dashboard below has the links to all the information, archives, videos, and links to workouts, podcasts, live Q and A lessons. 

Consider this! - A Membership Program and Gain Access to Exclusive Content
(click for Fitness Club Dashboard - members only)

Best of all, if you have questions, email Stew Smith himself (  Join the tactical fitness group discussions, latest articles, videos, podcasts at the Stew Smith Tactical Fitness Training Closed Group on Facebook.


Questions?  Just email -

At - List of Products and Services

  1. FREE Articles
  2. Podcasts and Swimming Videos (Youtube, TikTok, Instagram)
  3. eBooks
  4. Books and eBooks in PRINT
  5. Stew Smith Fitness Club membership site
  6. Online Coaching  

Stew Smith Fitness 

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