Critical Power (CP) is a term that is often associated with the sport of cycling. However, it’s a concept that can be used by anyone to track improvements in their overall fitness. Many of my clients, tactical and otherwise, seek to achieve a state of optimal general physical preparedness (GPP) and this is where Critical Power testing fills a need. I’m sure you’re wondering, what exactly is CP and maybe even what is GPP? Well, in layman's terms, CP is the maximum sustainable power output you can maintain for a given amount of time. Pretty cut and dry, right? GPP on the other hand is a bit more complicated. But, by the end of this piece it should be apparent that these two concepts are virtually synonymous.

Quantum Fitness

There’s a lot of hyperbole and cult-like zealotry surrounding certain GPP fitness programs. There are many reasons for this effect, but it’s largely due to a lack of understanding of what GPP represents. From a simplistic view, a well-conditioned GPP athlete must have the ability to produce degrees of work over various time domains (work capacity). Verkoshansky and SIff first proposed this idea; they defined work capacity as the general ability of the body as a machine to produce work of different intensity and duration using the appropriate energy systems of the body. This is the version of GPP that most of my work has been built upon. I believe that in order to reach a balanced state of GPP, one must develop a degree of symmetry across all of the Trainable Components of Fitness (musculoskeletal function, strength, power and energy-system bioenergetics). This leads us to the professed goal of many of my athletes, increased work capacity. For most trainees, increased work capacity is not only the goal, it’s also the measuring stick used to track progress. Unfortunately, it’s been difficult to scientifically measure improvements in certain bioenergetics without invasive laboratory testing. This is problematic because we obviously need to measure how much work an athlete can produce at different intensity and durations using the appropriate energy systems of the body in order to quantify ones work capacity. This is where critical power testing comes in because it allows us to establish baseline measurements in our anaerobic and aerobic energy systems; positive changes in these baselines validate a training programs efficacy.

Right Way Vs. Wrong Way

There are programs that incorrectly measure work capacity by using timed multi-modal workouts as testers. An example of this would be the CrossFit workout Fran (21-15-9 barbell thrusters and pull-ups). In this scenario, a new trainee is tasked to complete the work as fast as possible. For arguments sake, let’s say he completes the work-couplet in 10 minutes (strict pull-ups); this timed event is now used by his coach as a measure of his work capacity.

Fast forward through one month of training, his front squat has gone up 50 pounds, primarily due to improved kinesthetic awareness and he’s also been taught kipping (swing and use inertia) pull-ups; this new technique was proposed by his coach in an attempt to increase his ”power output”. Subsequently, the athlete retests his work capacity by completing Fran again. This time he completes the work couplet in 7 minutes. His trainer screams, “way to go brah, that’s a 30% improvement in work capacity!” Right? Wrong!

The problem with this scenario is:

1. A large portion of the original work was omitted by using the kipping pull-up. This obviously alters the testing equation and makes the outcome invalid. Essentially, we end up comparing apples to oranges.

2. The increases we see in the front squat are not true absolute strength gains; they were simply a result of improved biomechanics through neuro-physical adaptation. This training effect allowed the athlete to express his true strength, which he already possessed a month prior.

3. It’s difficult to discern actual improvements in the energy systems using this type of testing because when a new trainee is exposed to novel movement patterns repeatedly it leads to an increase in economy of movement. This is primarily due to the kinesthetic learning of proper motor patterns, which allows the athlete to perform the same tasks faster than he did before and while using less energy. It’s this economy of movement improvements that throw another proverbial wrench in the works when using multi-modal workouts to test energy systems gains. After all, each individual athlete has different thresholds, and a subjective approach such as this provides us with no data that’s indicative of positive or negative threshold gains.

At this point, it should be clear that tests such as Fran are largely useless when it comes to testing energy-system dependent work-capacity. Fortunately, this is where ideas like critical power can offer us diagnostic salvation. Critical Power can provide an athlete and coach with true empirical evidence of bioenergetic changes. This makes the critical power approach an invaluable tool in order to test training effects.

Trainable Components of Performance

As I’ve said before, it has always been my contention that optimizing an athlete’s capacity for work is dependent upon achieving a degree of balance across the trainable components of performance (T-Comp). This assumption logically deduces that when an athlete's fitness increases, so does their ability to produce more work. When I write an individual’s program, I focus on the T-Comp subsets that offer the most robust potential for cross-adaptation, which is usually strength training first. But, before I get too far into my model, I think it’s important that we briefly visit the ubiquitous term GPP.

In my opinion, optimal GPP is achieved when an athlete maximizes his potential without specializing. As you can see in the graphic below this state is visually represented by symmetrical scores across all of the Trainable Components of
Performance (TCOMP).

Optimal GPP permits the Athlete to safely and effectively complete a wide array of challenging neuro-physical tasks across various time parameters, as necessity arises. The presence of gross deficiencies in any portion of TCOMP can skew this outcome and obviously limits an athlete’s ability to specialize quickly. Quick specialization is a key component of what I espouse. For example: balanced GPP training offers a tactical athlete a broad base to quickly alter his training in order to specialize dependent upon the mission. If large deficiencies in the T-Comp model are present, this obviously limits this outcome.

In this regard, optimal GPP is unique to the individual and it is somewhat dependent upon prior training and the dualistic nature of the human mind and body. It’s also important to understand that the state of optimal GPP I’m referring to is not only dependent upon achieving symmetry in the Trainable Components of Performance, it’s also relative to the athletes potential (e.g., genetic potential, training-age, actual-age, musculoskeletal health and biologic predispositions).

For example: an untrained older-athlete may display symmetry in his T-Comp scores, which is common. However, this symmetry doesn't represent his true potential because he is untrained. It’s this example and others like it that will act as guideposts to direct the prioritization of each athletes training. Training must be prioritized in order to achieve the most cross-adaptation across all T-Comp categories by focusing on a single component, such as strength.

With this approach, the end goal is to create a balanced state of fitness that can act as a foundation on which we can specialize. The model I use at Phase Five is designed to elicit long term gains (which are sustainable long term) through focused meso-cycles that change when a high degree of potential has been reached in that specific T-Comp category (subjective to established norms and client goals). Once T-Comp scores have been ascertained, a framework can be established to begin creating an individualized training program. My model looks something like this.

Work Your Weakness: In Context

Pre-testing offers a coach insight into what an athlete needs in relationship to his goals and deficiencies. The detection of T-Comp deficiencies through testing gives a practitioner a starting point in which to prioritize an athlete’s training in order to facilitate maximum improvement in the shortest period of time. This process is instrumental in determining the training path that will offer the most cross-adaptation. Unless you’re already extremely strong, strength training offers the most impressive and comprehensive cross-adaptive effect for overall fitness. Regardless of which T-Comp focus is prioritized, there must be testing protocols in place for all of the Trainable Components of Fitness, not just strength.

So, what are the steps?

1. Measure musculoskeletal health through a training specific screen. (I use a training-specific musculoskeletal screen.)

2. Measure strength capacity by using Mark Rippetoe’s Starting Strength tables.

3. Measure Maximum Aerobic Function (MAF) through the 1 mile MAF test (Run 1 mile at a HR no greater than 180-age) A detailed description can be seen at http://philmaffetone.com/maftest.cfm or http://www.t-nation.com/free_online_article/most_recent/your_cardio_makes_no_sense.

4. Measure aerobic and anaerobic function through a Critical Power test.

Obviously, now our main focus is to look at Critical Power as a yardstick for measuring change in the capacity of our bioenergetics. This is largely due to the fact that up until now, testing anaerobic thresholds in the gym has been problematic. While there are many versions of CP testing, I’ve chosen to use a two-part version comprised of a three and 12-minute test.

It’s important to keep in mind that we’re not measuring absolute power as seen in a one-rep max snatch, but critical power, which is just another way of saying "average power," or the power you can maintain for a given time.

For example: how many watts can you average on an erg (rower) for three and/or 12 minutes? Logic would indicate you’d be able to hold a higher rate over three minutes verses 12. This is why we test both, so we can extrapolate that data to create a quantifiable metric to measure change in the aerobic and anaerobic energy system. This metric will be used in the future to track and measure improvements in work capacity.

So, how do we test work capacity? Easy, get on a bike or a rower that is capable of measuring watts. Over the course of two different training sessions, complete a three-minute test for max watts followed a few days later with another 12-minute test of max watts. Plug the average watt data from each time trial into this model. Critical Power is the curve defined by that maximal power output per the number of minutes of duration.

Great! So, what does that tell us? It shows us when muscular work is performed to exhaustion at different intensities. The slope of the regression of maximal work (work limit) on maximal time (time limit) is referred to as critical power (CP). The y-intercept of this function is considered to represent anaerobic work capacity (AWC). The purpose of this investigation is to examine the relationship between the y-intercept from the critical power curve and measures of AWC (total work accomplished, maximal blood lactate and post-exercise venous blood pH) gained from repeated, maximal exercise. (1)

Pros and Cons

The critical power concept is not without its limitations. In particular, it tends to greatly overestimate the maximal power that can be generated for only a few seconds, and it predicts that there should be a power output below which fatigue will never occur. In addition, the exact values obtained for W and critical power depend in part on the testing protocol, e.g., the exact combination of powers and durations used to define the curve, how fatigue is defined, etc. Nonetheless, despite its simplicity, this equation describes the power vs. duration curve quite well over a wide range of exercise intensities/durations, i.e., from perhaps 20 seconds out to several hours. (2)

There have been extensive studies within the scientific community on the critical power concept and its ramifications to sport. The version of measurement using CP that I propose we use is certainly simplistic, but by adding laboratory testing, it can become quite accurate. The take-away for most non-competitive athletes is that this form of critical power testing offers a way to measure improvements in their energy systems/fitness that mixed modal workouts fail to capture.

By testing one’s critical power every three to four months, athletes and coaches can gauge the efficacy of their previous training cycles based on changes in critical power. As I’ve alluded to before, this method of measuring GPP is not the end all be all, but rather a simple test with less potential to corrupt data like when using mixed modal testers. Critical Power testing may not be as sexy as doing “Fran”, but it’s a hell of a lot more accurate when it comes to testing work capacity.

GPP athletes who are looking to gauge their true work capacity can’t go wrong with using the tests that I’ve outlined above. These methods have offered my clients a safe and effective method of monitoring changes in all their trainable components of fitness regularly over many years. The key to long-term success in training is to work your weakness in the context of your goals, weaknesses and limitations. Constant testing, reflection and reevaluation of goals are integral parts of the training process that affords us the ability to train indefinitely. However, without the proper tools to test our current state of being, we end up proverbially chasing our own tail in search of an abstract and undefined form of “fitness.” At Phase Five, critical power testing has proven to be the missing link in developing a well-rounded testing catalog. It’s my hope that others can benefit from all the methods I’ve outlined here.






Sources:
1. Ergonomics. 1991 Jan; 34(1):13-22. The y-intercept of the critical power function as a measure of anaerobic work capacity. Jenkins, D.G., & Quigley, B.M. Source: Department of Human Movement Studies, University of Queensland, St. Lucia, Australia.
2. Power vs. duration: the "critical power" concept (First posted to the internet in 2002.) by Andrew R. Coggan, Ph.D.