The NCAA News - News & Features

Sports medicine rumor control

By Nancy Clark
SPORTSMEDICINE BROOKLINE

Athletes are always looking for a short cut to help maximize performance, consequently, rumors of success are rampant.

At the annual meeting of the American College of Sports Medicine (ACSM), in Cincinnati, May 29-June 1, exercise scientists tried to distinguish between fact and fairy tale. Here is what they found about some of the most popular substances:

* Creatine is the current "magic bullet" for power and sprint athletes who perform less than six minutes of intense exercise. Research, however, shows mixed results. One study with runners who raced for 700 meters (about two minutes), then rested for one hour and raced another 700 meters showed no enhanced performance, nor did another study with a 30-second bout of maximal cycling. Improvement occurred in a third study with repeated sets of high-intensity resistance exercise (jump squats and bench press). The general consensus is that creatine still needs to pass the test of time. In two years, we will know more.

* Eating before endurance exercise greatly improves lasting power. A British study suggests that eating 1.1 grams carbohydrate/lb. body weight (700 calories/150 lbs) three hours before, plus consuming a sports drink during an endurance run significantly extends running time to exhaustion. The subjects ran 147 minutes with the prerun meal and sports drink; 125 minutes with no breakfast and only sports drink, and 115 minutes with no calories before or during the run.

* Sports drinks improve not only endurance but also performance of high-intensity exercise that lasts less than an hour. When 19 trained cyclists consumed a sports drink (about 240 calories per hour) during a time trial, they improved their performance by 2.3 percent. This knocked more than one minute off their approximately one-hour event.

* Exercise-induced muscle cramps are thought to be caused by dehydration and loss of sodium and potassium, but that may not be true. Runners who suffered muscle cramps after a 35-mile race had similar serum sodium, potassium, and glucose levels, as well as similar hydration status compared to a runner with no cramps. But the runners with cramps had a higher EMG (electromyograph) activity, suggesting that the cause may be malfunctioning nerves.

* Strenuous exercise is rumored to cause oxidative damage that can lead to cancer; however, in a study with 29 male "ironman" triathletes, postexercise blood tests suggest this is not true. Strenuous exercise enhanced antioxidant capacity, especially among the men with high pre-exercise levels of serum vitamin E and vitamin C. Another study also suggested that exercise in healthy men and women (average age, 36 years old) generates a protective response from exercise-induced oxidative stress. In other words, keep exercising hard!

* Drinking alcohol after exercise results in reduced muscle glycogen storage when athletes displace carbohydrate calories with alcohol (that is, they drink beer but don't eat enough food). If you are going to drink alcohol, be sure to eat a high carbohydrate diet.

* Recovery carbohydrates are important for not only for endurance athletes, but also for those who train for strength. When eight healthy men (age 22) consumed .5 gm carbohydrate/lb. body weight immediately after performing heavy resistance exercise and then again one hour later, they had significantly less muscle protein breakdown than when they ate nothing.

* Does building muscle improve performance? When college football players were supplemented with about 800 calories of carbohydrate, Phosphagain or Phospagain II for five weeks of off-season resistance and agility training, the players who took the Phosphagain supplements gained more lean tissue mass, but showed limited performance gains.

* Steroids are attractive to high-school football players. The most effective drug-prevention programs teach the athletes not only about the dangers of steroids and good nutrition/exercise alternatives, but also how to refuse drugs.

* Is weight-gain with age inevitable? A 10-year study with 71 women (average age, 67 years), showed they tended to maintain the same overall weight but lost muscle and gained body fat, mostly in the trunk area. They also lost one inch of height. A study with masters-program swimmers divided into age groups (40-60, 60-plus years old) reported no age-related declines in VO₂ max. A third study comparing changes in body weight and fat in 108 men and women between ages 20 to 31 showed significant variation but, on average, a 15-pound weight gain. The variation seemed to be associated with specific characteristics of skeletal muscle. (A low aerobic-oxidative profile may contribute to fat gain.)

* For all you Breathe Rite fans, three researchers reported no performance benefits with using these nasal strips. This demonstrates yet another example of how we should not believe every ad we see in popular sports magazines.

Nancy Clark is a nutritionist at the Boston-Area Sportsmedicine Brookline. She can be called at 617/739-2003.