VO2max

The monthly newsletter of RunCoachJason.com

Jason Karp, professional coach, consultant, freelance writer

June, 2005

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In this issue:

Abdominal Training

What Determines VO2max?

Breathing and Stride Rate

Need a Personal Trainer?

Research on Kenyan Distance Runners

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Abdominal Training

Why do people train their abdominals differently than other muscles?  The abdominal muscles, including the superficial rectus abdominis and external obliques and the deep transversus abdominis and internal obliques, contract and get stronger just like any other skeletal muscle.  If you wouldn’t do 200 biceps curls to shape your arms, why do 200 crunches to shape your midsection?  All the Saturday morning T.V. infomercials that claim their revolutionary abs machine will shed fat and inches off your waistline are lying.  Since it takes a deficit of 3,500 calories to lose one pound, crunches will only shed fat and inches if you do enough of them to burn thousands of calories (this would take millions of crunches).  So what burns thousands of calories, you ask?  I’ll give you one guess…      

 

Cardiovascular exercise.  You can do as much abs training as you want, but you still won’t see your abs unless you also do cardiovascular exercise (read: run) to get rid of the fat that lays over the muscles and beneath the skin.  All people with flat stomachs or six-packs have a very low percentage of body fat.  Just ask runner Marla Runyan.

           

By the way, the six-pack that Runyan and others have is not six separate muscles or three pairs of muscles; there are no “upper” and “lower” abs.  Each “section” of the six-pack is part of the entire vertical muscle that is separated by horizontal inscriptions of a tendon.  When muscles contract, fibers along the entire length of the muscle shorten.  They do not contract with only part of their length.  There is no evidence that upper and lower sections of the rectus abdominis can be preferentially recruited.

 

It’s funny to watch people in gyms because they tend to make movements that they would never do anywhere else.  I’ve seen lots of people in gyms hang from their arms and lift their legs up toward their chests or lay on their backs and raise their legs toward the ceiling.  When lifting the legs rather than bending the waist, the rectus abdominis is relatively inactive, only contracting statically to anchor your torso in place.  The hip flexors (iliacus, psoas major, and psoas minor) and tensor fasciae latae muscle, rather than the abdominals, are responsible for lifting the legs upward (and it just looks silly).

           

To decrease the stress on your spine when doing crunches, bend your legs at the knees with your feet on the floor.  You can also lift your legs in the air and cross them at the ankles, which will tilt the pelvis downward, pressing the small of your back against the floor and decreasing the arch in your back.  To increase the activity of the abs, lay on a movable surface, such as an inflatable exercise ball.  And don’t forget to run.

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What Determines VO2max?

VO2max, the maximal amount of oxygen that your muscles consume per minute, is important for distance running success.  But how is it determined?  First, our hearts must pump blood through the arterial circulation to get oxygen to the muscles and second, our muscles must extract the oxygen from the blood so they can use it to make energy for contraction.  The former is dependent on stroke volume (SV, the volume of blood pumped per beat) and heart rate (HR) and the latter is reflected by the difference in the amount of oxygen (O2) going to the muscles through the arterial circulation and the amount coming out through the venous circulation (a-v O2 diff).  VO2 is simply equal to the product of these variables: VO2 = SV x HR x (a-v O2 diff).  Since SV x HR equals cardiac output (CO, the volume of blood pumped per minute), the equation can be written as: VO2 = CO x (a-v O2 diff).  VO2max occurs when SV, HR (and therefore CO), and the a-v O2 diff are at their maximum.

 

Cardiac output is determined by the return of blood back to the heart, the heart’s ability to contract quickly and forcefully, the amount of pressure in the left ventricle (preload) and in the aorta (afterload), and the size of the left ventricle.  The a-v O2 diff is determined by the convection of oxygen  through the muscle capillaries and its diffusion from the capillaries to the mitochondria .  Since the amount of oxygen in the arterial circulation is the same at rest as it is during a race (20 ml of oxygen per 100 ml of blood), any change in the a-v O2 diff is a result of a decrease in oxygen in the venous circulation, which means the muscles have extracted more oxygen.

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Breathing and Stride Rate

Many animals, including humans, coordinate their breathing patterns to their rhythms of movement.  Coordinating the two rhythms may be something that is subconsciously learned with many miles of running and may benefit runners by improving their economy.  I discuss the interesting issue of entrainment of breathing to stride rate in Lungs and Legs, in the June, 2005 issue of Track Coach magazine.

 

For more information about training and related topics, check out my other publications at http://www.runcoachjason.com/publications.

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Need a Personal Trainer?

Do you or someone you know want to get in shape for the summer?

Do you want well-defined muscles?

Do you want to fit into the clothes you used to wear, including the dress or suit that has been sitting in your closet for years?

Are you ready to make a change?

Coach Jason can help you get in shape by customizing an exercise program specifically for you.  He will work with you either online or in person to help you meet your goals.  For more information, or to hire Coach Jason as your personal trainer, e-mail jason@runcoachjason.com.  

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Research

Interested in the reasons for the Kenyan distance runners’ success?  Exercise and cancer?  The effects of exercise on insulin resistance and diabetes?  How U.S. Olympic Marathon Trials qualifiers train?  From June 1-4 in Nashville’s famed Opryland, hundreds of nerds, uhh, I mean scientists, gather to discuss research on these and other topics at the 52nd annual conference of the American College of Sports Medicine.  Stay tuned for a recap in the July newsletter.

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To view past newsletters, go to http://www.runcoachjason.com/newsletter.

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©2005 Jason Karp. All rights reserved.