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Aerobic Capacity Training, Part 2: Pacing

There are many additional benefits of aerobic capacity training to those discussed in Part 1, but they can be summarized in one word: pacing.  Pacing sometimes has a negative connotation to the arrogant, who might stereotype it as what wimps or losers do.  Winners charge out of the gate and don’t slow down!  Except that if you charge all out you will slow down when your glycolytic energy system is out of fuel, your muscles are chock full of lactate, and your heart rate is pegged at its maximum.  If you’re fit, that won’t happen for events less than 2:00, so if that’s the time domain the workout or event demands, by all means, slam the throttle and Go!  But for anything beyond 2:00, finding your maximum sustainable pace for the time you expect it to take is the highest intensity – and wisest – choice you can make.

…for anything beyond 2:00, finding your maximum sustainable pace for the time you expect it to take is the highest intensity – and wisest – choice you can make.

Simple test: run for 100m as fast as you possibly can.  How fast will you choose to run?  Pretty darn fast (relative to your body’s top speed), since 100m won’t take a very long time, and your phosphate & glycolytic energy systems can provide plenty of energy for that period of time.  Rest a bit, then run 1 mile as fast as you possibly can.  You could start out at your 100m pace, but you’ll exhaust those two energy systems and still have 1,500m left to go.

Obviously, the sensible thing to do is to run as fast as you think you can possibly hold for the full mile from the start.  This will feel relatively easy at the beginning, since you are full of oxygen and not using your glycolytic energy system at its maximum rate.  Your pace will not be near your body’s top speed, and your heart rate will not be at maximum.  To start.

Related: Why 50-60% of 1 Rep Max Makes You Fitter

As you continue to run, the byproducts of glycolytic metabolism will build up, signs of stress will multiply, and your mind will start talking to you, trying to get you to slow down.  If you have chosen your pace wisely, and are applying strong “mental fitness” – positive self talk and other techniques that help you resist the mind’s calls to slow down – you will run out of gas and be forced to stop just as you cross the finish line.  That is how you run the fastest mile you are capable of running.

CrossFit is a Constantly Varied selection of Functional Movements performed at High Intensity.  Your highest average intensity for a workout is achieved with proper pacing, rather than going out too fast, crashing, recovering mid-workout, and then resuming a high pace.  This fast start —> slow middle—> fast finish can create the false impression of high intensity.  It happens all the time.

Our famous 21-15-9 rep scheme gives us an easy example: You blow the doors off the round of 21, but were completely anaerobic, and collapse (at least metaphorically – you may still be on your feet, but probably with your hands on your knees) as you struggle through a 4 or 5-set version of your 15 reps of each exercise, gasping after not even a handful of reps.  This does allow you to recover, and, hey, it’s just 9 reps, so you blow through the round of 9, collapse on the ground, make your sweat demon, and pat yourself on the back for your “high intensity” workout.  But what you really did was turn a single high intensity workout – go hard, finish with everything you have – into an interval workout – sprint, rest, sprint.

The latter will not give you the benefits you would have received from a more evenly paced workout.  On top of that, you would’ve finished the whole thing faster had you found a pace you could hold throughout the workout rather than sprinting, resting, and sprinting (see, for example, the tale of the Tortoise and the Hare).

I once had a swim coach advise me to sprint everything in the 200 yard Individual Medley because you’re switching strokes every 50 yards, so you’re switching muscle groups, so it’s just 50 yards of a stroke, which is a sprint.  But those different muscle groups are all running off the same three energy systems!  The change does mean that you can go a little harder than you would for 200 of one thing, but you still cannot treat it as an all-out sprint and expect to finish with the fastest time you are capable of.  The truth is, even for CrossFit events with lots of different elements, such as the Filthy 50’s 10 different movements, pacing is a critical skill.

The more aware we are of our heart rate, breathing, the way the working and non-working muscles feel, the more we get to know what a given effort feels like, the better we can adjust our pace. 

Aerobic Capacity workouts give us the opportunity to focus on our pacing and get to know the physiological signs of our effort.  The more aware we are of our heart rate, breathing, the way the working and non-working muscles feel, the more we get to know what a given effort feels like, the better we can adjust our pace.  This allows us to check in during a met-con and determine how we are doing relative to our desired effort.  We can then adjust our pace and/or apply mental fitness as needed to finish in our best possible time.

Related: Training for Obstacle Course Racing

Pacing training also expands the range of time domains we can prepare for in the gym, despite our one hour class times.  You don’t need a 90-minute workout to practice your 90 minute pace.  Let’s say you’re preparing for a half-marathon, and want to train your body to finish in about 90 minutes.  That’s right under 7:00 per mile, so you can start by running a mile in as close to 7:00 as possible.

But you can also break that down further – it’s 3:30 for 800m, 1:45 per 400m, and 0:55 per 200m.  So you can run repeats of any of those distances for the goal time, and the process will teach your body and mind what a 7:00 pace feels like.  This will allow you to settle into your pace more quickly, and hold it more accurately over the course of the race, without ever having to do a full race-effort half marathon in training (which would be rather silly, wouldn’t it?).

By learning to pace properly, you can achieve and maintain the highest intensity you are capable of for a given time domain.  By practicing the required intensity for a longer event for shorter periods of time, you prepare your body and mind to understand – to “feel” – what it’s like to hold that pace, dramatically increasing your ability to actually hold your desired pace and thus achieve your goal for that event.  This makes us more capable, happier, and more confident athletes, capable of tackling whatever we set our minds to.

—John Bryant

Founder & Head Trainer

CrossFit Slipstream

john@crossfitslipstream.com