Science experiments make a splash; a look at sports science will improve your science-project technique - the scientific method: includes related articles - Special Issue: Science Project Success Guide

Science World, Sept 20, 1996 by Chana Freiman Stiefel

Whether they know it or not, all athletes rely on science before, during, and after a competition. Sports scientists constantly work behind the scenes to design better equipment, help prevent injuries, and improve athletes' performance. These scientists-including sports doctors, equipment designers, and exercise specialists - have one thing in common. To get results, they all use the scientific method, a step-by-step way of doing research and sharing results.

DIVE IN AND OBSERVE

The scientific method takes off with observation. That's the simple act of noticing something like a characteristic of a person or an object.

For instance, during her years as Director of Exercise Physiology for U.S. Swimming, Jaci VanHeest has observed that swimmers train in a variety of ways. Some use fast-paced, short-distance sprint workouts; others prefer long, slow endurance swims, still others train with fast-paced, long-distance swims.

VanHeest wondered which training technique most improved a swimmer's performance. After all, her organization trains the best swimmers in the country - Olympians like Janet Evans and Tom Dolan. Finding out the best training technique could give future Olympians a winning edge.

So VanHeest formulated a research question: What's the effect of training technique on swimming performance? She then did some background research to see if anyone else had done studies on that topic. She discovered that you can test how well a training technique works by measuring how much oxygen a swimmer uses while working out. (The more oxygen your muscles take in, the faster and longer you can exercise.)

Based on this research and her own knowledge, VanHeest then stated her hypothesis - an educated guess about what the answer to her research question might be. She predicted that swimmers who train with fast, long-distance swims would use oxygen most efficiently. They would also show the most improvement in their swimming performance.

TESTING, TESTING

VanHeest then set out to design an experiment, a way to test her hypothesis. An experiment must be carefully constructed to test the effect of one variable, or characteristic, on another. In an experiment, the variable you investigate to determine its effect is called the independent or manipulated variable. That's because you change, or manipulate, this variable on purpose. In VanHeest's experiment, the independent variable is training technique.

The variable you measure to see if the independent variable has any effect is called the dependent or responding variable. Many times the value of this variable depends on, or responds to, the change you make in the independent variable. In VanHeest's experiment, the dependent variable is oxygen use (and ultimately, the ability to win races).

CONTROLLED CONDITIONS

VanHeest conducted a pretest to pleasure several swimmers' oxygen use. For this test, called an oxygen-consumption test, swimmers wear a mask while swimming. One tube collected to the mask floats above the water so the swimmers can breathe. Another tube collects the air each swimmer exhales and feeds it to a computerized analyzer on the pool deck. The computer compares the oxygen content in the inhaled and exhaled air to figure out how much oxygen a swimmer uses while training. (The less oxygen a swimmer exhales, the more efficiently his or her body is using the gas.)

VanHeest found 30 swimmers who all used about the same amount of oxygen during a swim. She picked similar swimmers because she planned to use these pretest measurements as a control for her experiment - a standard against which to compare the effects of the different training techniques. She also kept all other conditions - like the duration of the oxygen test and temperature of the water - constant, or unchanged, during the experiment. That way these variables would not affect the results.

She then divided the 30 swimmers into three equal groups. One group trained by swimming short distances at high speed. A second group swam long distances at a steady, fast speed. The third group swam long distances at a steady, slow speed. Each group trained five times a week for eight weeks.

Then VanHeest repeated the oxygen-consumption test for each swimmer. In most cases, she tested each swimmer more than once and took an average measure of oxygen use. These repeated trials are important in an experiment because they make it less likely that some chance variable (like a swimmer having an "off" day) will alter the results.

After comparing the oxygen use of each group, VanHeest reached a conclusion, a summary of her results. The fast, long-distance swimmers showed the most improvement in oxygen use and performance. So VanHeest recommended this technique for some of this year's Olympians.

The rest of this special issue will take you through the steps of the scientific method - from helping you come up with art experiment idea of your own to publishing your results. With our tips, your science project should be a real "stroke" of genius!