Recently, I have been adding more cardiovascular activity to the workouts I do with local military recruits and myself and have developed a fun but challenging program. You can easily alter the events to your preferences and future military / law enforcement training and use these programs to maintain a high operational fitness level. I call it the Military Triathlon!
Phase 1 of the Spec Ops Triathlon: The first segment of the workout consists of a standard aerobic routine. If you are seeking more land based training then I would suggest performing the 3-6 mile timed run. It is up to you if you want to run this in boots / pants or regular training gear.
Phase 2 of the Spec Ops Triathlon: The next segment is great for those of you are seeking more Navy, USMC, Coast Guard, or water Special Ops type training. I suggest doing a 1000-1500m swim with fins after performing the run. Some like to push this distance with fins and build up to 2-3 mile swim with fins.
Phase 3 of the Spec Ops Triathlon: After the swim, dry off and put back on your gear but this time pack a ruck with 40-50 lbs of gear in it and perform a 6 mile timed ruck.
Overall, this is not that bad of a workout. It takes a few hours to do. You can always get creative and add some upper body PT after the run or the swim. Perhaps doing a max rep superset of pull-ups, pushups, sit-ups in a non-stop circuit until you do five complete sets or hit a group of goal numbers like 100,200,300 (pull-ups, pushups, situps) will complete your PT workout.
Another addition is to add some squats and lunges every 15-20 minutes of the ruck. Try adding 20 squats and 10 lunges each leg during your ruck (with ruck still on!) for your 60-90 minute ruck march.
I usually do the military triathlon once every other week or once a month and always after a day off of workout activity. After the military triathlon, make sure you re-hydrate, get proper electrolytes, eat well and enjoy the rest of your day. You earned it!