VO2max

The monthly newsletter of RunCoachJason.com

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

Director & Coach, REVO₂LT Running Team™

April, 2009

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In this issue:  

San Diego Personal Training Summit

Dr. Jason Karp to Speak at American College of Sports Medicine Conference

Marathon Fatigue

Strides

Coaching Consultations

In Press

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San Diego Personal Training Summit

RunCoachJason.com’s San Diego Personal Training Summit for personal trainers and fitness professionals will be held on April 18, 2009 at the Marina Village Conference Center in San Diego, California.  

Speakers include exercise physiologist, coach, and author Dr. Jason Karp, American Council on Exercise curriculum developer Fabio Comana, M.A., M.S., and corrective exercise specialist Justin Price, M.A. 

The summit will feature presentations on the biggest issues in the fitness industry, including the truth about changing resting metabolic rate, the scientific research on the most effective weight loss strategies, marathon and cardiovascular training, assessing and correcting deviations of the feet to improve function, how to train movement patterns rather than exercises, and how to organize the details of training into a cohesive, results-driven program using periodization.  If you want to be a more effective trainer, or if you just want to find a competitive edge to boost your bottom line, you cannot afford to miss this unique summit.  Bring a friend or colleague and you each save 20%!  To register, go to http://www.runcoachjason.com/personaltrainingsummit.

All attendees will receive:
- Continuing education credits for ACE and NSCA personal trainer certifications
- 10% discount on fitness equipment and accessories at Fitness Direct
- FREE PowerBar products
- Raffle for FREE Polar heart rate monitor
- Raffle for FREE acupuncture treatment

- Raffle for FREE active release technique treatment & biomechanics evaluation
- Raffle for FREE one-hour massage
- Raffle for one-month VIP pass to UrbanBody Gym
- Raffle for 25% discount to Great Earth Vitamins

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Dr. Jason Karp to Speak at American College of Sports Medicine Conference 

If you’ll be in the Seattle area at the end of May, I will be speaking at the 56th Annual American College of Sports Medicine (ACSM) Conference May 27-30 at the Washington State Convention and Trade Center.  On May 27, I will be chairing the symposium, Chasing Pheidippides: The Science and Coaching of Distance Runners that includes guest speakers Jack Daniels, Ph.D. and Hal Goforth, Ph.D.  I will also be presenting my dissertation research, Lungs and Legs: Entrainment of Breathing to Locomotion in Highly-Trained Distance Runners.  

ACSM is the largest sports medicine and exercise science organization in the world.  The annual academic conference brings together scientists in the areas of exercise physiology, biomechanics, physical therapy, exercise and sport psychology, motor learning and control, sports medicine, and biochemistry.  For more information and to download the event brochure and conference schedule, go to

http://www.acsm.org/AM/Template.cfm?Section=Annual_Meeting2&Template=/CM/ContentDisplay.cfm&ContentID=11560.  To register for the conference, go to http://www.acsm.org/source/Meetings/cMeetingFunctionDetail.cfm?section=Register&product_major=AM2009&functionstartdisplayrow=1. 

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Marathon Fatigue

Continuing with our discussion of fatigue, this month we examine the marathon.

Given the length of the marathon, there are some things that limit your performance that don’t play a major role in shorter races.  The main difference is that you run out of carbohydrate, which is your muscles’ preferred fuel.  You have enough stored carbohydrate (glycogen) in your muscles to last slightly more than two hours of sustained running at a moderate intensity.  Glycogen depletion and the accompanying low blood sugar (hypoglycemia) coincide with hitting the infamous wall.  Once you run out of glycogen and blood glucose, your pace will slow down.

Other issues not encountered in shorter races that affect marathon performance include dehydration, muscle fiber damage, hyperthermia, and psychological fatigue.  When you sweat a lot, you become dehydrated, which causes a decrease in the plasma volume of the blood, decreasing the heart’s stroke volume and cardiac output.  Oxygen flow to your muscles is then compromised, and the pace slows.  The relentless pounding on the pavement causes muscle fiber damage, which decreases muscle force production.  Since your muscles produce heat when they contract, running for long periods of time increases body temperature and the resulting hyperthermia decreases blood flow to the active muscles since more blood is directed to the skin to increase convective cooling.  Finally, running for so long can cause psychological or neural fatigue, the latter of which is due to changes in the levels of brain neurotransmitters. 

To combat fatigue in the marathon, you need to do high mileage, long runs, tempo runs, and long intervals.  A high training volume improves many aspects of aerobic metabolism, including the number of red blood cells, hemoglobin concentration, muscle capillary and mitochondrial volumes, and aerobic enzymes, together resulting in a greater oxygen-carrying capability and greater ability to use the available oxygen.  High mileage also seems to improve running economy, the oxygen cost of maintaining a given pace. 

Long runs present a threat to the muscles’ survival by depleting their storage of fuel.  Given adequate ingested carbohydrates following the long run, our bodies respond rather elegantly to the “empty tank” by synthesizing and storing more glycogen, thus increasing endurance for future efforts.  However, molecular evidence suggests that holding out on the muscles by delaying the consumption of carbohydrates may be even more beneficial.  By “starving” the muscles of carbohydrates, even more glycogen may be synthesized when carbohydrates are finally consumed.  Low muscle glycogen content has been shown to enhance the transcription of genes involved in protein synthesis.  Long runs also help you combat the psychological and neural fatigue by practicing to tolerate prolonged exertion.

Tempo runs improve your lactate threshold, the fastest speed you can sustain aerobically and above which fatigue-inducing acidosis occurs.  Increasing your lactate threshold pace allows you to run faster before you fatigue because it allows you to run faster before oxygen-independent metabolism begins to play a significant role.  This is paramount for the marathon, which is basically a test of how long you can sustain a hard aerobic pace.  The goal of marathon training is to increase the pace at which your lactate threshold occurs and to increase your ability to sustain as high of a fraction of your lactate threshold as possible.  Try 3 to 4 miles, increasing to 7 to 8 miles, at lactate threshold pace (about 10 to 15 seconds per mile slower than 5K race pace or about 10K race pace for recreational runners, and about 25 to 30 seconds per mile slower than 5K race pace or about 15 to 20 seconds per mile slower than 10K race pace for highly trained runners) or 5 x 1 mile at lactate threshold pace with 1 minute rest.  If you’re experienced with doing many long runs and you want to give your marathon performance a boost, try inserting lactate threshold-paced running into some medium-long runs (12 to 16 miles).  These LT/LSD combo runs let you simulate the physiological and psychological fatigue of the marathon without having to run as far.  They also severely lower muscle glycogen, stimulating its synthesis and storage. 

Long intervals (3 to 5 minutes) increase your heart’s stroke volume and cardiac output, sending more blood and oxygen to your muscles and increasing your VO₂max.  You should come close to reaching your maximum heart rate by the end of each work period.  High-intensity training (95 to 100% VO₂max) is the optimal stimulus for VO₂max improvement. Try 5 x 1,000 meters or 7 x 800 meters at VO₂max speed (about 2-mile race pace for good runners) with equal (or slightly less than equal) time as recovery.

Other things you can do to combat fatigue in the marathon are 1) ingest carbohydrates during the race, 2) drink fluids with sodium, and 3) run long on pavement.  That muscles prefer carbohydrates as a fuel is so fundamental to exercise metabolism, even research examining supplementation with carbohydrate during prolonged exercise has shown that fatigue can be delayed.  Begin ingesting glucose about 30 minutes before you hit the wall so the glucose has time to be absorbed into your blood where it can be used for energy.  Since your sweat rate exceeds your ability to ingest fluid while running, dehydration is difficult to prevent.  However, since endurance performance declines with only a 2-3 percent loss of body weight due to fluid loss, it’s important to minimize its effects.  Since water goes wherever sodium goes, more water is conserved by the kidneys when you ingest sodium with the water.  Finally, unless you’re planning on running a trail marathon, do all of your long training runs on pavement to prepare for the muscle fiber damage you’ll sustain in the race. 

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Strides
There are a number of lightning-fast steps that occur for muscles to contract and produce force, all starting with the central nervous system, including the transmission of a signal to a motor neuron, the release of a neurotransmitter (acetylcholine) at the neuromuscular junction, the depolarization of the muscle, the propagation of an action potential deep inside the muscle, the release of calcium ions from the muscle’s sarcoplasmic reticulum, the interaction between contractile proteins (actin and myosin), and the hydrolysis of ATP for muscle contraction.  To run fast, the central nervous system has to increase the number of motor units recruited and increase the frequency of stimulation of the motor units.  Thus, running fast is a strong stimulus for the central nervous system.  While most of a distance runner’s training is cardiovascular and metabolic in nature, sometimes you have to focus on the neuromuscular aspect of performance.  

Strides are one of the things you can do to focus on the neuromuscular aspect.  Strides are 10- to 25-second (50 to 150 meters) controlled sprints.  The purpose of strides is largely neuromuscular: to increase stride rate by recruiting fast-twitch motor units (muscle fibers), which increases speed and, more importantly, to increase stride length by increasing joint mobility (especially at the hip) and increasing leg muscle power, causing a greater propulsive thrust.  The short bursts of speed also improve your coordination and running form.  

Strides, like other neuromuscular and technique work, should be performed at the beginning of the training session (after a warm-up) or after an easy run, when you’re still fresh.  Strides for a distance runner are analogous to starting block drills or plyometrics for a sprinter or hurdle drills for a hurdler.  It’s about making fast movements efficient.  Thus, doing strides after an interval workout that causes a large amount of fatigue defeats the purpose of the strides.  When you’re fatigued, stride length naturally decreases.  Any neuromuscular or power training requires greater recovery than endurance or metabolic training; thus, you should take full recovery between strides.  Taking only a few seconds of recovery between strides introduces a metabolic demand.  Making strides too long also introduces a metabolic demand, so strides should not be longer than about 25 seconds, otherwise you will start to cause acidosis. 

When running strides, aim for a fast, smooth feeling.  Don’t press to go fast—they should not feel like intervals.  Rather, relax and focus on moving your legs quickly through the running cycle to increase stride rate, and (more importantly) extending your legs behind you from the hip to increase stride length.  Take as much time as you need between each one to feel recovered.  Try to do strides on the track; if you can’t get to the track, find a flat stretch of road or other firm footing. 

Want to know more about organizing the components of your training program?  My popular DVD—Chasing Mercury, Battling Hercules: Getting Fitter and Stronger with Periodization Training—provides an overview of training theory, reviews research findings, discusses the use of training cycles, and provides examples of how to properly organize all of the components of training.  To order a DVD, just go to http://www.runcoachjason.com/merchandise.
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Coaching Consultations

Are you having trouble meeting your running and fitness goals?  Do you coach other runners and want to know how to improve their performances?  RunCoachJason.com can help.  We offer the best consultations for runners, coaches, and personal trainers.  If you want to improve your running performance, or you want the opportunity to have your fitness and running questions answered immediately, you can talk to Coach Jason live.  For a list of consultation topics and to book a consultation with Coach Jason, go to http://www.runcoachjason.com/consulting. 

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In Press...
How Fast Can Johnny Run?: Assessing Sprinting Ability, my article that describes the various ways coaches can evaluate possible sprint talent, appears in the Spring, 2009 issue of Track Coach, the official technical publication of USA Track & Field. 

Do you have short limbs?  You may be at a greater risk for Alzheimer’s Disease and dementia when you get older.  Size Matters, my short piece on this subject, appears in the March/April, 2009 issue of Maximum Fitness. 

Target Heart Rate, my response to a personal trainer’s question about how best to determine a client’s target heart rate, appears online at Personal Training on the Net, an online education resource for personal trainers and fitness professionals. 

Which is the Best Type of Cardiovascular Equipment?, a podcast of my article that examines the research on the best cardio equipment for burning calories, can be heard live at http://www.itrainerlive.com.

Top 3 Cardio Workouts, my article on the top 3 fitness-inducing, fat-burning cardio workouts, appears online this month at RoadRaceResults.com and Sportstats.ca.

Five Lessons I Have Learned From Physiology and How They Can Make You a Faster Runner appears in the Spring, 2009 issue of Duke City Fit, Albuquerque, New Mexico’s premier fitness magazine.

Rapid Descent, my article on downhill running with tips on how to prepare for downhill races, appears in the May, 2009 issue of Runner’s World, on newsstands in April.

Also check out my quotes on fitness and peaking in the March/April, 2009 issue of Marathon & Beyond and walking on an incline treadmill in the April, 2009 issue of Fitness. 
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To view past newsletters, go to http://www.runcoachjason.com/newsletter.

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©2009 Dr. Jason Karp.