The Clinic.

TRAINING SHOES VERSUS RACING SHOES

Many shoes are advertised as training shoes, as is my current shoe. My races usually consist of half-marathons and marathons. I've only used "training" shoes for racing so far. I am fairly flat-footed, but I don't overpronate. I use a counter force arch brace when I run and have been injury-free. Should I consider using something other than a training shoe and if so which ones would you recommend I try?

Rich Honig

Plainview, NY

A good quality training shoe can certainly be worn for half and full marathons. Several factors must be considered before switching to a racing flat. Racing flats should only be worn by highly-competitive, bio-mechanically efficient, lightweight runners, and only for racing. If anything, with your flatfoot structure and need for an arch brace, you would be safer to use a more supportive, straight-lasted, anti-pronation shoe.

Because you have been running safely with your current shoe, I would advise you to stick with what works. Changing to a new type of shoe often results in changing the biomechanics of your foot and leg, leading to possible injury

Matt Werd, D.PM

Lake/and, FL

If you are planning to race in racing flats, it is a good idea to train in them occasionally as the heels are somewhat lower than regular running shoes. Racing in them may lead to Achilles tendon problems. By training occasionally in racing flats, the Achilles tendon will adapt somewhat to the lower heel.

Melvin Williams, Ph.D.

GLYCOGEN SPARING OR GLYCOGEN REPLACEMENT

When I started doing marathon training in the mid-80's I was taught that long runs help train the body to properly store and utilize glycogen and ultimately this improves endurance performance. Now the advice seems to be to take gels and/or replacement drinks every half-hour to provide the sugar needed for training or racing. What happened to training the body to do the job on its own? Which is correct?

Ty Lourie 

Bar Harbor 

Actually, they both are. As more and more research is done in the area of sports nutrition, we are learning that some of the tried and true methods can be improved upon. This is one.

Remember that your body's capacity to store glycogen is limited to about 1,800 to 2,000 calories, or enough for about 90 to 120 minutes of vigorous activity. Your muscles and liver can store only so much glycogen, despite endurance training. We know that eating food or drinking carbohydrate replacements during exercise can help delay the depletion of muscle glycogen and prevent hypoglycemia and "bonking" or "hitting the wall." Trained athletes have a better ability to burn the carbohydrates taken as fuel during intense endurance exercise, thus relying less on muscle glycogen and blood glucose. This leaves the body, post exercise, in a much healthier state, and particularly speeds recovery if you are training regularly.

Glycogen-depleted muscles are more susceptible to soft-tissue injuries. It takes about 24 hours to thoroughly replenish muscle stores, so if you have a bit left at the end of your event or training, all the better. Also, remember that it has been found that by ingesting a small amount of protein post event (one gram protein to three grams of carbohydrate) the rate at which your muscles store glycogen is boosted.

Sarah Harding Laidlaw

Glade Park, CO

Here is a rebuttal to the recommendation to take gels or sports drinks to provide carbohydrate for training or racing--doing so does not train the body to utilize fat, which can provide a huge source of energy for long distance running. Fat is not automatically burned. Your body must adapt to burning fat. Without constant carbohydrate replenishment the body uses fat as the main fuel source in running long distances.

Michael Yessis, Ph.D.

Escondido, CA

AGE-RELATE DECLINE IN PERFORMANCE

How much of a decline in running performance should I expect from age 47 to 53 given about the same training regimen and about a five-pound weight increase? For the half-marathon I was able to run 1:35 at age 47, and 1:38 at age 50. As approach 53 this year I'm unable to break 1:50. I admit I have trained a bit less but is there anything else to explain this drop in performance?

Fred Jacques

Jersey City, NJ

Unfortunately aerobic capacity declines with age. However, this decline in active adults is about half of that in a sedentary individual if exercise is performed consistently at the same overload (frequency, intensity, and duration) and body composition is maintained. For typical sedentary American adults, VO2max declines about one percent per year Your decline seems about what would be expected; especially given a slightly reduced training load and a slightly increased body weight (every one-percent increase in body fat can reduce performance by one percent). By increasing your training overload, you could possibly shave five or six minutes off your half marathon time. However, be aware that as you age, your need for rest and recovery during hard training increases. In order to avoid over-training syndrome and overuse injuries you need to plan your training very carefully.

Fritz G. Huber, Ed.D., C.S.C.S.

Tulsa, OK

Try adding strength training to your program. It will increase running economy, endurance, and possibly stride length. Adding muscle mass also increases your metabolic rate at rest, which will help you to shed some of those added five pounds.

Doug Lentz, C.S.C.S.

Chambersburg PA

MAINTAIN CARDIOVASCULAR BENEFITS WITH FEWER MILES

I'm 75 years old and have been running for 20 years including 128 10K races! Now I'm running just for my cardiovascular health, four days per week, four miles a day. Can I cut my running down to three days a week, four miles a day, and still get the benefits of training for cardiovascular health?

Godwin J. Sampey

Gray, LA

First, I'd like to salute you for your long running and racing career--congratulations! The scientific literature and fitness experts tell us how much we need to exercise in order to obtain the greatest cardiovascular health benefits.

* The classic Harvard Alumni study done by AMAA Member Ralph Paffenbarger, M.D., found that the lowest death rates from cardiovascular disease occurred among those who burned at least 2,000 calories in vigorous physical activity per week.

* The Cooper Institute recommends 36 to 45 aerobic "points" for high fitness and optimal health benefits.

* The American College of Sports Medicine, Centers for Disease Control and the Surgeon General Report on Physical Activity and Health recommend accumulating at least 30 minutes of moderate physical activity most days of the week. This is the amount of physical activity that burns around 150 calories per day or at least 1,000 calories per week.

If you run about a 10-minute mile pace and weigh approximately 170 pounds, this would mean that you burn around 2,080 calories (13 calories/minute times 10 minutes times four miles times four days a week). Your current level of activity would meet the criteria of the Harvard Alumni study of 2,000 calories per week. If you cut back to a three-day schedule you would burn 1,560 calories, still very beneficial to cardiovascular health, perhaps not the "ideal" of 2,000 calories burned per week.

From the perspective of The Cooper Institute, running four miles in 40 minutes is worth around 15 points. Running this distance three times per week (15 points times three times a week) would still provide a high level of fitness and the optimal health and cardiovascular benefits.

If the running mileage in your schedule were the only physical activity in your week, you would fall short of the ACSM, CDC, and Surgeon General recommendations.

I would encourage you to run every other day because it allows your body to recover a day between running bouts (not a bad idea for anyone over age 50). If you want to make up for the fewer calories burned by not running the fourth day to meet the "ideal" of the Harvard study, then I suggest walking two miles (or 30 minutes) on the other three days you do not run. You would bum a little over 500 calories by walking, bringing your total calorie expenditure up to the 2,000-calorie per week ideal. This level of activity would also meet the ACSM, CDC, and Surgeon General recommendations. It gives you adequate time for rest and recovery--three days of relative rest, and one day of complete rest.

John McPhail, C.R.C., L.P.C.

Okemos, MI

RELATED ARTICLE: ARE YOU BOTHERED BY AN INJURY? DO YOU HAVE A TRAINING OR DIET QUESTION?

Ask The Clinic, in care of The American Running Association. 4405 East West Highway. Suite 405. Bethesda, MD 20814. FAX [phone]. or e-mail at [e-mail]. Write a letter Including as much relevant information as possible about you (age, weight. etc.) and your Injury (type and location of pain), training schedule (typical weekly workouts, pace, surface). athletic and medical history. sole wear, recent changes in training. etc. Type or print your letters. Hand-written FAXed letters cannot be accepted. All letters, even e-mail, must include your name, address and phone number. Responses usually take three to four weeks, but can take as long as five.