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Posted: November 9, 2005
Science of Sport: Critical Velocity - A Pace Between
By: Chris Puppione
With the rise of the Internet Age has come a rise in the number of readily accessible “oracles” of distance training knowledge. Many of these online personalities pass themselves off as pillars of wisdom in the running community on the message boards of such popular websites as Letsrun.com and Run-Insight.com. With all of their grandstanding and carelessly constructed late-night revelations, however, these false prophets mingle with some very well-educated, and sometimes, famous individuals (the likes of Dr. Jack Daniels, Renato Canova, and Brad Hudson) discussing everything from nutrition to mileage to interval training and threshold training. And thankfully, some of these interludes diverge from the juvenile jabs and blind-leading-the-blind blather, and turn the heads of even the most knowledgeable runners, coaches, and exercise scientists.
One such topic was able to span across several message boards and spawned many great responses, demanding that we, as students of the sport, take a second look. The topic of this discussion, and more specifically of this article, pertained to something called “critical velocity.” This term, which sounds very imposing and forceful, is just as transparent and seemingly without definition as some of our other profound training terms in distance running (i.e. lactate threshold, anaerobic threshold, etc.) Just as these other terms have been given multiple names with just as many numerical values, so too has critical velocity in the scholarly literature of the physiological community. It has been referred to as critical speed, critical power, and critical velocity, with paces ranging from vVO2 MAX down to that which would be comparable to MLSS (maximal lactate steady state, or a blood lactate level of approximately 4 mmol). With such a convoluted list of differing terms and paces, how then do you reconcile the initial question: What is critical velocity? And once that issue is resolved, then you must address the next quandary: How will training at my critical velocity improve my performance? In the end, by training at critical velocity, you can improve your aerobic profiles by:
1. Bringing about greater fractional utilization of VO2 MAX in order to race faster at a lower percentage of VO2 MAX for a given distance.
Where Does The Term CV Come From?
What Does CV Mean In Training Terms?
USATF Coaches Education Program’s % of VO2 MAX Pace Chart
800 meters 120-136% of VO2 MAX 1500 meters 110-112% of VO2 MAX 3000 meters 100-102% of VO2 MAX 5000 meters 97-100% of VO2 MAX 10000 meters 92% of VO2 MAX Lactate Threshold 88% of VO2 MAX Half-Marathon 85% of VO2 MAX Marathon 82% of VO2 MAX
Critical velocity, then, would be within the range of 89-91% of VO2 MAX, but where? Schwartz says that this is up to the individual coach. “If you are looking for greater gains in VO2 MAX, set your critical velocity closer to 10K pace. If it is lactate threshold improvement that is more essential to you, place the pace close to lactate threshold velocity.”
We know from the training literature of Dr. Joe Vigil and Dr. Jack Daniels that VO2 MAX improvements can be made by exercising at 90-100% of VO2 MAX. We also know that the most significant training component for an athlete in an endurance event is the lactate threshold session, in which an athlete is looking to train to delay OBLA (onset of blood lactate accumulation) in order to perform at a higher intensity for longer before the body is crippled by H+ ions – ions that accompany acidosis, which leads to a reduction in speed over time. If you were able to train, then, at a pace that stimulates VO2 MAX and raises the lactate threshold, Schwartz says that this would improve your ability to run farther faster, and at a lower energetic cost.
“It is about extensibility,” says Schwartz. “If an athlete can extend their speed over a greater distance at the same effort as before—that is the goal in training distance runners. That is what training at the critical velocity is about.” Therefore, by adding critical velocity sessions to your training program, you will be able to improve your fractional utilization of VO2 MAX —something Dr. Vigil cited in his article from an earlier issue of Peak Running (July/Aug 2005) as being vital to the success of Deena Kastor in Athens. By improving your fractional utilization, you can perform at a faster pace for a longer distance at a lower percentage of VO2 MAX velocity, thereby bringing about improvement across all distances relating to submaximal velocities. Using critical velocity sessions will allow you to improve your buffering capacity during extended periods of exercise—i.e. go longer and faster at a higher blood lactate concentration level.
Why CV And Not LT Or 10K?
There are two reasons for choosing to train at a velocity between these two conventional paces. The first aspect to consider is that when you train at 10K pace (or 92% of VO2 MAX), the volume of this work must be reduced because of the respective intensity. Top collegians may do up to 10,000 meters of work at this pace, but they will need substantial amounts of recovery from the wear and tear this can have on the body. The potential for injury or soreness from a session of this magnitude is certainly increased. However, by training at critical velocity, an athlete can still reap the benefits of VO2 MAX stimulation by running at the reduced intensity of 90% VO2 MAX and increase the volume of work. This lends itself to the idea of extensibility—covering more distance at a smaller cost of energy—by allowing the coach to boost an athlete’s VO2 MAX while concurrently raising their lactate threshold. The second reason for training at this pace is that when you train at the lactate threshold, you are not stimulating your VO2 MAX, making the training session very one-dimensional. By turning the intensity up a notch (by a mere 2-3%), you can bring the VO2 MAX stimulus into the picture while continuing to bolster the lactate threshold (without crossing dangerously into a state of distress). Several studies have shown that by training at a pace just above lactate threshold velocity, you can, in fact, raise your lactate thresholds more effectively than by training below this pace. So the argument then becomes, why not train faster? This also adheres to the goal of extensibility, wherein you can now train at a pace that will allow you to not only run for longer distances with less fatigue, but also to do so at a faster pace at a smaller percentage of VO2 MAX. In turn, this athlete will also be able to call upon a greater percentage of their VO2 MAX during longer races, allowing them to carry a greater velocity longer—i.e. improved fractional utilization of VO2 MAX.
Determining Your CV Pace
What Makes Up A CV Training Session?
1. Warm-up 10-20 minutes; dynamic warm-up drills; light strides 2. 3-4 x 2000 meters @ CV pace w/ 2:00 rest 3. 5-10 minute light jog 4. 4-6 x 200 meters @ 1500m effort w/ 200 jog recovery 5. Cool down 10-20 minutes; stretch; ice Runner A Current 10K Time: 30:36 (4:53.7 per 1600m) Critical Velocity: 4:56.0-5:00.0 per 1600m CV Workout: 4 x 2000 meters @ 6:10-6:15 w/ 2:00 rest 6 x 200 meters @ 1500m effort w/ 200 jog recovery Runner B Current 10K Time: 35:00 Critical Velocity: 5:37-5:41 per 1600m CV Workout: 4 x 2000 meters @ 7:00-7:05 6 x 200 @ 1500m effort w/ 200 jog recovery Runner C Current 10K Time: 40:00 Critical Velocity: 6:26-6:30 per 1600m CV Workout: 4 x 2000 meters @ 8:03-8:08 6 x 200 @ 1500m effort w/ 200 jog recovery
The 200 meter repeats at the end of the session are important; we are calling upon you to finish the workout at a faster pace, much like the final laps of the 5,000 or 10,000 meter races. We are conditioning you to run faster in a fatigued state.
Where Does CV Fit Into The Annual Training Cylcle?
Because college runners have generally trained at a high level for several years, gains in VO2 MAX may be minimal, depending upon an athlete’s training age and mileage. However, with critical velocity, you can improve your capacity to run at a greater velocity at all percentages of your VO2 MAX. This means improvement in all aerobically dominant events, which we have learned range in distance from the 800 meters to the marathon. Therefore, in the latter part of a cross country season, training at critical velocity while working concurrently on improving velocity at VO2 MAX is especially important. As you improve your maximum velocity at the point of your maximum oxygen uptake, you will also be enhancing your ability to run faster at a lesser aerobic cost.
Once you have accomplished this improved state of fractional utilization at the end of your racing season, you do not want your progress to slip to pre-racing levels, so you must stimulate the system early in the build-up for outdoor track. Also, because of critical velocity’s correlation to 10,000 meter pace, it serves as a fine way to build the athlete into the outdoor racing season and for the bigger upcoming meets. Then, during the months of March and April, we shift our focus to training at and below race pace, with lactate threshold improvement taking a secondary role. Because of the increase in intensity—both in racing and training—we find it wise to move away from the more aggressive LT-improvement method of critical velocity in order to improve the quality of our race pace sessions. However, as the end of the season comes around, with the volume of work decreasing a bit, we do not want to allow our aerobic system to suffer from lack of stimulus. Therefore, we bring critical velocity back into play in order to “get more bang for your buck”—by reducing volume, you are set for the most important meets while still massaging your VO2 MAX. This will boost your lactate threshold, and maintain the integrity of your overall aerobic profile. Below is a training sample week that includes a critical velocity session:
A Sample Week of Training Including a CV Session
M – Recovery run w/ grass strides to follow (mileage as needed)
T – Repetitions @ 3K-5K pace (3000-8000 meters total volume) w/ short reps @ 800m-1500m effort to follow
W – Medium run @ 75-80% of VO2 MAX (15% of weekly mileage)
TH – Recovery run w/ grass strides to follow (mileage as needed)
F – Repetitions @ CV pace (4000-10000 meters total volume) w/ short reps @ 1500m effort to follow
SAT – Recovery run (mileage as needed)
To CV Or Not To CV
Billat LV (2001) Interval Training for Performance: A Scientific and Empirical Practice Part I. Sports Med 31 (1):13-31.
Chris Puppione is the Assistant Cross Country/Track & Field Coach at the University of California, Davis. He is currently completing his M.S. degree in Exercise Science, and can be reached with questions and comments at firstname.lastname@example.org.
© Copyright 2005 Peak Running Performance. All Rights Reserved. Reprinted with permission
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