VO2max

The monthly newsletter of RunCoachJason.com

Dr. Jason Karp, running & fitness coach, consultant, freelance writer

Director & Coach, REVO₂LT Running Team™

June, 2008

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In this issue:  

Free T-Shirts at Rock 'n' Roll Marathon

VO₂max Distance Running Clinic Comes to San Diego

The Runner’s Heart

Muscle Fibers and Running Performance

Training Programs

In Press

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Free T-Shirts at Rock 'n' Roll Marathon

If you’re running in or attending the Rock 'n' Roll Marathon on June 1, 2008 in San Diego, California, get a free REVO₂LT Running Team™ T-shirt and coaching info from RunCoachJason.com’s Dr. Jason Karp.

For more information on the Rock 'n' Roll Marathon, go to http://www.rnrmarathon.com/home.html.  For more information on RunCoachJason.com’s coaching services, go to http://www.runcoachjason.com/coaching.

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VO₂max Distance Running Clinic Comes to San Diego

On July 19th, 2008, RunCoachJason.com will hold its second annual VO₂max Distance Running Clinic for runners, coaches, and fitness professionals at the Marina Village Conference Center in San Diego, California.  Named after the most popular physiological variable related to distance running, the VO₂max Distance Running Clinic will transform your running.  Speakers include exercise physiologist, coach, and writer Dr. Jason Karp, sports nutritionist Kim Mueller, M.S., R.D., and former road 10K American record holder and 4-time Olympic Trials qualifier Thom Hunt.  Enjoy a relaxed, elegant atmosphere with other runners and coaches in San Diego’s beautiful Mission Bay while you learn the best scientific methods to take your or your athletes’ performances to the next level. And you may even win a free pair of running shoes!  For more information or to register online, go to http://www.runcoachjason.com/clinic.  To download the clinic brochure, go to http://www.runcoachjason.com/Brochure.

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The Runner’s Heart
The amount of blood the heart pumps with each contraction of its left ventricle (the heart’s largest chamber that is responsible for sending blood to every part of your body except the lungs) is called the stroke volume.  Multiply the stroke volume by your heart rate, and you get the amount of blood pumped by your heart each minute, called the cardiac output.  The larger your left ventricle, the more blood it can hold; the more blood it can hold, the more blood it can pump.

Interest in the cardiovascular adaptations to endurance training have been of interest to scientists and health professionals since at least the time of the documented enlarged heart of distance runner Clarence DeMar, who won the Boston Marathon seven times between 1911 and 1930.  So characteristic is a large heart of genetically gifted and highly trained runners that it is considered a physiological condition by the scientific and medical communities called Athlete’s Heart.  While you may never attain the heart size and associated cardiac output of elite runners like Clarence DeMar, specific training can make your heart larger and increase your stroke volume and cardiac output.

Long intervals provide the heaviest load on the cardiovascular system because of the repeated attainment of the heart’s maximum stroke volume and cardiac output (and your VO₂max).  Evolutionary biologists believe that the structure of an organism evolves to cope with the stresses to which it is subjected, which has led to the theory of symmorphosis—that an organism’s structural design is regulated by its functional demand.  Remarkably, structural changes can also occur in the short term in response to training: bones increase their density, muscle fibers increase their metabolic machinery, and cardiac muscle grows larger.  In response to the imposed threat of running at your heart’s maximum ability to pump blood, your heart responds by increasing its contractility (pumping velocity and strength) and by enlarging its most important chamber so that more blood and oxygen can be sent to the working skeletal muscles.  The larger left ventricle is called left ventricular hypertrophy, and is diagnosed from an electrocardiogram and an echocardiogram.

So, how fast should you run to induce left ventricular hypertrophy?  The best stimulus is the speed that corresponds to your maximum cardiac output (maximum heart rate times maximum stroke volume) which, along with the maximum difference in oxygen content between arterial and venous blood, determines your VO₂max.  Therefore, run at the velocity at which VO₂max is achieved (vVO₂max).  In lieu of a laboratory test to tell you that velocity, you can use current race performances or heart rate.  vVO₂max is close to 1-mile race pace for recreational runners and close to 2-mile race pace (10 to 15 seconds per mile faster than 5K race pace) for highly trained runners.  Heart rate monitors are great for this type of workout—you should be within a few beats of your maximum heart rate by the end of each interval.  Examples of workouts are: 3 x 1,200 meters (or 4-5 minutes) at vVO₂max with 3 to 4 minutes recovery; 4 x 1,000 meters (or 3-4 minutes) at vVO₂max with 2½ to 3 minutes recovery; and 6 x 800 meters (or 3 minutes) at vVO₂max with 2½ to 3 minutes recovery.

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Muscle Fibers and Running Performance

When you race, are you able to hang with your competitors during the middle stages, but get out-kicked in the last quarter- to half-mile, or do you have a hard time maintaining the pace during the middle stages, but can finish fast and out-kick others?  Which type of workouts feel easier and more natural—long intervals (800-meter to mile repeats), long runs, and tempo runs, or short, fast intervals (200s and 400s)?  Which workouts do you look forward to more—long intervals and tempo runs, or short and fast intervals?

Your answers to these questions get at an important, often overlooked concept in running physiology—muscle fiber type.  There are two types of runners—those who have superior speed, whose performance gets better as the race gets shorter, and those who have superior endurance, whose performance gets better as the race gets longer.  Most runners, unless they are individually coached, follow some generic training program.  However, those programs don’t acknowledge differences in runners’ muscle fiber types and their associated metabolic profiles.  The types of fibers that make up your individual running muscles greatly influence your performance.

Humans have three different types of muscle fibers, with gradations between them.  Slow-twitch (ST) fibers are recruited for all of your aerobic runs, while fast-twitch B (FT-B) fibers are only recruited for short anaerobic, high-force production activities, such as sprinting and jumping.  Fast-twitch A (FT-A) fibers, which represent a transition between the two extremes of ST and FT-B fibers, are recruited for prolonged anaerobic activities with a relatively high-force output, such as racing 400 meters.  While distance runners have more ST fibers than FT fibers, there is still a disparity in the amount of ST fibers, as some runners may have 90 percent ST and 10 percent FT fibers, while others may have 60 percent ST and 40 percent FT fibers.  

Understanding your fiber type can help you train smarter.  While most runners do the same workouts to focus on a specific race, your training and racing should reflect your physiology.  For example, if you have 90 percent ST and 10 percent FT fibers, your best race will likely be the marathon and your training should focus on mileage and tempo runs.  If you have 60 percent ST and 40 percent FT fibers, your best race will likely be the 800 meters or mile, and your training should focus less on mileage and more on interval training.  If both runners want to race a 5K or 10K, the former runner should initially do longer intervals, trying to get faster with training, such as 1,200-meter repeats at 5K race pace, increasing speed to 3K race pace or decreasing the recovery as training progresses.  The latter runner should do shorter intervals, trying to hold the pace for longer with training, such as 800-meter repeats at 3K race pace, increasing distance to 1,200 meters or increasing the number of repeats as training progresses.  Thus, there can be two paths to meet at the same point.  

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Training Programs

Want to improve your running or train for a specific race like a 5K or marathon?  With RunCoachJason.com, you’ll get a specific, science-based training program suited to your needs.  To purchase Dr. Jason Karp’s popular customized training programs for beginner, intermediate, and advanced levels, go to http://www.runcoachjason.com/customprograms.  

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In Press...
Chasing Pheidippides: Training to Combat Marathon Fatigue, my article that discusses the major causes of fatigue in the marathon, with advice on how to combat them, appears in the May/June, 2008 issue of Marathon & Beyond.

Four Lessons I Have Learned from Physiology and How They Can Make You a Faster Runner appears in the June, 2008 issue of Running Times.

Training Characteristics of U.S. Olympic Marathon Trials Qualifiers, my research article documenting how the best marathoners in the U.S. train, with comparisons made between men and women and elite and national-class runners, appears in the June, 2008 issue of New Studies in Athletics, the official technical publication of the International Association of Athletics Federations.

Much has been written about strength training for the runner—everything from lunges while holding dumbbells to calf raises on the edge of a stair to endless repetitions of abdominal crunches while balancing on a big, lime green exercise ball.  Does anyone else reading these training suggestions ever wonder if they will really lead to a new 5K or marathon personal record?  The Long View, my article on how strength training, only when done for power, can improve your running, with sample programs for strength and plyometric training, appears in the Summer, 2008 issue of Techniques for Track & Field and Cross Country, the official technical publication of U.S. Track & Field and Cross Country Coaches Association.

The Top 3 Cardio Workouts, my article on the top three fitness-inducing, fat-burning cardio workouts, appears online at Personal Training on the Net, an online education resource for fitness professionals.

Activating Muscles: How to Change Body Position When Lifting Weights, my research-based article that discusses changes in body position and grip that changes the muscular emphasis of a variety of exercises, appears in the June, 2008 issue of the United Kingdom’s Ultra-Fit magazine.

High School P.E. Class Revisited, my article that revisits the old school exercises you did in high school gym class, appears in the Summer, 2008 issue of Duke City Fit.
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©2008 Dr. Jason Karp.