VO2max

The monthly newsletter of RunCoachJason.com

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

July, 2006

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In this issue:

Customized Training Programs

How Many Sets Do You Need to Gain Strength?

Science of Running Mechanics

VO2max and Pulmonary Diffusion

Hydration

Exercise and Immune System

In Press

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Customized Training Programs

Want to PR at a 5K, 10K, half-marathon, or marathon but can’t make a long-term commitment with a coach?  Remember, you can purchase my popular customized training programs for beginner, intermediate, and advanced levels.  Just e-mail jason@runcoachjason.com.

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How Many Sets Do You Need to Gain Strength?

Ever wonder if 1 set of weight training is just as effective as multiple sets?  Well, it may depend on the muscle groups.  A study published in Journal of Strength and Conditioning Research in 2003 found that 3 sets is superior to 1 set for leg exercises but not for upper body exercises.  Untrained subjects who performed 3 sets of leg exercises and 1 set of upper body exercises (using a 7-rep max load 3 times per week for 6 weeks) increased leg strength more than subjects who performed 1 set of leg exercises and 3 sets of upper body exercises.  However, subjects who performed 3 sets of leg exercises and 1 set of upper body exercises had similar increases in upper body strength as subjects who performed 1 set of leg exercises and 3 sets of upper body exercises. 

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Science of Running Mechanics

From the very beginning of civilization, when man took his first tentative steps, we have been intrigued by human locomotion.  Initially, running was vital for survival.  The Neanderthal, in need of acquiring food for his family, would run through the woodlands chasing after live game.  Running, and being able to run long and fast, was very important.  It would be many years before man would discover the wheel and the Autobahn.  Now, thousands of years later, we are still fascinated by human locomotion, one example of which is illustrated by parents’ joy at their child’s first steps.  In fact, a child’s ability to walk is deemed so important that we label this occasion a milestone, and document the exact day the child’s first steps were taken.  This ability to move is met with even more joy from the children themselves when they discover the freedom that running confers, as boys race each other on playgrounds across the country, showing off their speed to the girls during recess. 

 

Even at that young age, it is evident that something unique is taking place when we move on two legs.  Indeed, it is a form of locomotion that makes humans unique from most other animals.  The attraction to running has prompted many coaches and scientists to study ways of moving faster.  While the classic photography of Eadweard Muybridge in Animals in Motion (1899) and The Human Figure in Motion (1901) may have been the first attempt at illustrating locomotion, and is still referenced as the authority on animal gaits, the oldest documentation of a scientific study of running may be the classic book of Giovanni Alphonso Borelli (1608-1679), De Motu Animalium (Of Animal Motion), in which he notes the relationship of leg length and stride frequency to running velocity.  We now know that, running velocity, in its simplest, most mechanical form, is equal to stride length multiplied by stride frequency, although it is questionable that leg length is strongly correlated to stride length and velocity in distance runners.  In the 20th century, the most prominent researcher of locomotion may have been R. McNeill Alexander of the University of Leeds in England, who has combined zoology and physics to help elucidate the complexities of animal movement. 

 

Technology like electromyography, video motion analysis systems, force platforms, and signal processing systems allow us to study things like muscle activation during the stride cycle, velocity, acceleration, and joint angles of the limbs while running, the amount of force at different parts of the foot upon landing and push-off, and the coordination of the breathing and stride rhythms, as I am researching for my dissertation. 

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VO2max and Pulmonary Diffusion

As you might imagine, there are many places through which oxygen must travel to get from the air you breathe into the mitochondria of your muscles where it is used to produce energy (ATP) for muscle contraction.  This “oxygen cascade” has been extensively studied by physiologists.  It has been suggested in the scientific literature that the VO2max of elite distance runners may ultimately be limited in the lungs, specifically where oxygen must diffuse from the alveoli into the pulmonary capillaries.  Because elite distance runners have a large cardiac output, the amount of time that red blood cells are in the lungs (called the red blood cell transit time) is very short, possibly too short for all of the oxygen to bind to hemoglobin in the pulmonary capillaries before going through the left side of the heart.  If a diffusion limitation exists between the lungs and the pulmonary capillaries, oxygen will not effectively diffuse into the capillaries, and both the arterial partial pressure of oxygen and the arterial oxygen saturation will decrease, leading to hypoxemia (reduced oxygen in the blood). 

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Hydration

When the temperature rises in the summer, it’s easy to become dehydrated.  Water, which is lost through sweat while you run, is vital for energy production inside your muscles.  When you lose water, your blood volume decreases, which decreases your cardiac output.  Your blood also becomes thicker, which decreases flow to your muscles.  Your ability to exercise declines with only a 2 to 3 percent loss of body mass due to fluid loss.  For best hydration, drink fluids containing sodium, which stimulates your kidneys to retain water.  If your workout is of a low intensity and lasts less than one hour, all you need is water in combination with a balanced diet.  A good indicator of hydration level is the color of your urine: it should be light.  If your urine looks like apple juice, keep drinking.

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Exercise and Immune System

Ever notice that you get fewer colds when you run?  Many studies have shown that moderate exercise performed on a regular basis strengthens the immune system and confers resistance against the common cold and other upper respiratory tract infections.  However, strenuous bouts of prolonged exercise and intense training over a period of time have the opposite effect: they depress the immune system and increase the chance of infections.  This is also true in the few days after running a marathon.   

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In Press...

The Errors of Our Running Ways, my article that examines four common mistakes—going out too fast in a race, doing speed work without first doing enough aerobic mileage, running workouts too fast or too slow, and not eating after a workout—with advice on how to correct them, appears in the July/August, 2006 issue of Running Times.

 

The Magic of Muscles, my article that describes the physiology of muscles and how they work, appears in the July/August, 2006 issue of Her Sports magazine.

 

Carbohydrates and The Distance Runner: A Scientific Perspective, my research-based article on the role that carbohydrates plays in distance running, with recommendations for maximizing muscle glycogen synthesis, appears in the Summer, 2006 issue of Track Coach.

 

Optimal Recovery, my article that discusses strategies for recovery from hard workouts, including refueling, rehydrating, reducing inflammation, and tapering, appears in the Summer, 2006 issue of Duke City Fit.

 

My Fitness News contributions on interval training, downhill running, and menstrual cycle and bone health appear in the July, 2006 issue of Oxygen magazine.

 

Workout Express, my column that details a 30-minute cardio workout, an accompanying playlist of songs, and a single “must-do” strength exercise, appears in the July, 2006 issue of Shape magazine.

 

My Fitness News contributions on exercise and anxiety, rehydration after workouts, and the role of the lungs during exercise appear in the August, 2006 issue of Oxygen magazine, on newsstands in July.

 

Also look for coverage of my research on chocolate milk as a post-exercise recovery beverage and my quote on treadmill vs. outside running in the July, 2006 issues of SELF and Fitness magazines.

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©2006 Jason Karp.  All rights reserved.