Friday Favorite Workout — Core and Cardio Day

Marine recruits execute a side plank.
Recruits with Mike Company, 3rd Recruit Training Battalion, execute a side plank during a physical training session at Marine Corps Recruit Depot, San Diego, June 23, 2020. (Lance Cpl. Zachary T. Beatty/U.S. Marine Corps photo)

Taking a workout session and mixing in several cardio options like running, rucking, biking, swimming or rowing that get the blood pumping at a moderate pace is great for the heart and lungs. Adding in core training, mobility and flexibility exercises can take a cardio-only day to the next level. 

Not only will you feel like you did something useful, but the full engagement of the core (from neck to the hips) and stretching will add a level of "feel good" to the end of your workout. The sense of accomplishment is different but addictive once you feel your lungs open and those typical aches and pains diminish.

Here is a workout I like to do when I have time to train, but little or no equipment.

Warm up with a short jog or bike for 10 minutes and follow it with a light stretch. Then, do the PT Reset circuit that starts the core on the back side of the body at the neck and shoulder level and works it down to the lower back and hips. Consider this a core warmup as well.

The core is a system that connects the head to the legs. Everything from the neck to the hips (front, back, sides) is your core. Core is not just the abdominal muscles most people focus on developing (often to the detriment of the lower and upper back). 


It is up to you what "easy" means, as intensity of training is all relative to the individual. The goal here is to get your heart beating at a nice zone 2 level. This is roughly 70%-80% of your max heart rate. 

Calculate that number using the equation 220-age = max heart rate (MHR). If you are 40 years old, your ballpark MHR is 180; 70%-80-% of that is a range of 125-145. That is the effort level you are seeking with this cardio workout.

Once you have completed your run or walk, mix in some more difficult core and hip flexor exercises.

Repeat 2 times

If you have a bike or stationary bike available, a nice ride is a great non-impact cardio activity that can work the legs, especially if you manipulate the resistance or find hills to ride up and down for part of your training time. 

Mix in a variety of workouts from Tabata Intervals (fast 20 seconds, followed by slow 10 seconds) for 5-minute sets. 

You can also try a pyramid for resistance increases each minute on the minute until you can no longer pedal at a 70-80 rpm on a stationary bike that allows for resistance changes.

Repeat 3 times

The final piece of cardio is your choice and depends on your time available, as well as your available options. You can also opt to walk, ruck, bike, row or use the elliptical machine if you do not have access to swimming (or prefer not to get wet).

Yes, this is a longer-than-average workout, but relatively moderate in intensity on the cardio. You may find the core sections somewhat challenging if many of these are new to you or you are not used to doing them. 

Often on these longer holiday weekends, you may find yourself with extra time but little equipment. If you are looking to get away and just clear your head from some of the stresses that holiday travel and visiting can cause, try this and come back refreshed and feeling better than when you started. 

-- 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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