Why “Rx” Isn’t Always Best (ft. Coach Marissa)

  November 14, 2016

Train Smarter, Then Harder

“Rx Isn’t Always​ Best”

As an athlete most of us have been there. Standing in front of the whiteboard you

anxiously listen to the coach explain the “WHAT” of the workout and an

explanation of Rx weights/standards. This is the point where your inner-coach

can show up and you start internally debating over what weight to use and

sometimes the reason you miss the “WHY” we are asking you to train this way.

Everyone wants to be able to do do a workout Rx, but sometimes doing a workout

just because you want to hit the little blue button means you might be missing the

point. Strength and the lure of a heavy barbell can often be the first measure of

progress a novice athlete gravitates toward, however our goal in programming is

achieving peak functional fitness​. Functional fitness involves training the body for

daily life activities. These exercises equip your body to handle real-life situations.

With that in mind, let me expand on how that factors into how we train.

The Crossfit view of fitness uses three different standards for defining and

measuring fitness. The first is based on the ten general physical skills widely

recognized by exercise physiologists: cardiovascular/respiratory endurance,

stamina, strength, flexibility, power, coordination, agility, balance and accuracy.



A training regimen is only as effective as its ability to show

improvement/competency in each​ of these ten skills. Focusing in only one aspect

of these skills will result in deficits in overall fitness. An athlete that can deadlift

a #500 bar can easily boast of his strength. However, if he can’t run 400m

without fear of collapsing he can’t say much about his level of functional fitness.

This athlete could help lift a tree off of you, but if you needed him to carry you any

sort of distance to get medical care..your fate is probably in jeopardy.

The second standard is based on performance of any and all athletic tasks,

presented in an infinite variety of combinations. This is where the “constantly

varied” tenant of Crossfit comes into play and why you will see every conceivable

task, rep scheme, rest period and order of exercises when we train. We strive to

keep the stimulus broad and challenging. This is why it is important to work your

weaknesses, be consistent in training and not just show up on the days we are

doing something you are really good at. Your ability to do a pullup, knock out a

dozen push ups (meeting the standards of movement) is just as important a factor

in fitness as how heavy your squat is and our goal is to train you in a manner that

builds skill and efficiency across the board.



The final basis of how we measure fitness has to do with the energy systems that

drive all human action. The body has three metabolic pathways (main energy

systems) that are used to provide energy for all human action: phosphagen,

glycolysis, and oxidative systems. Energy is derived from a molecule, adenosine

triphosphate (or ATP as we learned in Biology). Training in these systems help

replenish ATP, which in turn increases our work capacity. The phosphagen

system is the predominant energy system used for all out exercise lasting up to

about ten seconds and is active at the start of all exercise regardless of intensity.

Max lifts in the 1-3 rep range or sprints are good examples of training in this

system, but due to the limited amount of stored ATP in the muscles fatigue will

occur rapidly. This is why rest periods are sometimes programmed in with the

workout or why we stress the importance of resting in between sets on strength

training. The second energy system is glycolyti​c and dominates moderate

powered activities. Glycolysis is the breakdown of carbohydrates (either stored in

the muscle or delivered in the blood, to produce energy. This system is activated

when an activity lasts anywhere from :20 to 3:00. Fran is a benchmark workout

that is intended to test the glycolytic energy system. An athlete that can complete

forty five #65 thrusters might feel justified in attempting to Rx Fran, but if she

needs 12:00 to accomplish it has missed the intended stimulus behind this

workout and turned it into a strength session. Doing so will make you stronger at

thrusters and pullups, but the goal of Fran is speed. Lastly the oxidative​ (aerobic)

system is the primary source of ATP at rest and during low intensity activities.

The oxidative system primarily uses carbohydrates and fats as sources to create

ATP. As the intensity of exercises increases your body uses mostly carbohydrates

as an energy source. This energy system is used mostly when activity lasts longer

than 2:00 and is relatively lighter in intensity. Those 5k days we all love would be

a good example of training in this system. Which system is being used to supply

energy for training is determined primarily by the intensity and secondarily by the

duration of the exercise. Because Crossfit is constantly varied, we program in way

that targets all three of the systems in order to elicit the highest overall level of




As Crossfit founder Greg Glassman has said … “The magic is in the movement, the

art is in the programming and the science is in the explanation.” Coaching

sometimes requires leading athletes in a different direction than they want to go,

hopefully reading this helps explain the bigger picture we are looking at when we

do so. We are always going to push athletes to train at an intense level, but the

goal is to get you to train smart, and with an overall purpose as well. I also can’t

go without saying, achieving the full benefits of training also requires attention to

your nutrition and recovery. Should you have any questions on how to do this,

please contact myself or any of the coaches on staff at River to River Fitness.

See you at the box,

Marissa Oliver


Crossfit L1 River to River Fitness

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