smaller men usually hit slap shots, their sticks hitting the ice first, then the puck.

"However, the harder, faster shot," Ariel explains, "is when the stick hits down on the ice first, because it bends and becomes loaded with energy that is transferred to the puck." Hockey coaches-used to searching for and training big men-were skeptical until Ariel demonstrated, and proved, his point. Afterwards they had to agree, but only grudgingly, and so far there is no evidence of their insisting on the slapshot when a player has a choice. Ariel doesn't understand why most coaches won't incorporate his findings.

"I don't say I have the final answer," he says of his biomechanical research, "but that there is a tool available that has been proven effective."

Ariel's tool, the means by which he

'sees slow," is slow-motion photography, to which he weds highly sophisticated electronic and computer technology. The result is an analysis that interprets the significance and contribution of each body segment-forearm, leg, or a particular muscle or joint-to the motion of the whole. To illustrate his system, take one of Ariel's most celebrated successes.

Before competing in the 1976 Olympics, American Mac Wilkins was filmed at his specialty, throwing the discus. Ariel's high-speed camera exposed 500 frames of film per second (it's capable of 10,000 fps, a speed used to see what happens to golf and tennis balls, and clubs and rackets during impact), to produce footage of Wilkins' form in slow motion. The film was projected onto a screen lined with 20,000 minute directional microphones. Freezing the film at numerous stages throughout the discus-throwing motion, Ariel touched various joint-centers of Wilkins' body-knees, elbows, ankleswith a magnetically sensitive Graf-Pen digitizer to measure their angles and lengths. This information was fed through the microphones into a computer, which produced a printout-numerical data from which Ariel could determine the velocity, rate of acceleration or deceleration, center of gravity, joint force, and exact moment of maximum exertion at any instant during Wilkins' motion. The numbers also supplied Ariel with information about the magnitude of muscle action at each joint, vertical and horizontal forces at

the ground contact points, the timing of

an action, and the coordination between

body segments. Finally, the computer

electronically produced a stick-figure

diagram of Wilkins on a small television

screen. With this schematic, Ariel could

analyze individual aspects of Wilkins'

form to determine what changes in his

body angles, timing, velocities, and

weight distribution would improve his

performance.

Ariel's print-out sheets and stick-fig

ure athletes were beyond the comprehension of Wilkins, as they would be to

anyone without experience in the rarefied world of computers. But moved by Ariel's enthusiasm and athletic background, Wilkins decided to hear what the man had to say.

Ariel told him he was not making efficient use of his legs, specifically that his front (left) leg was continuing to turn as he moved into release position as well as coming off the ground too soon; by continuing to move, the leg was absorbing energy that could be transferred to the toss. So Wilkins changed his technique. He learned to plant his front leg more firmly on the ground and keep it there longer, thereby setting up a solid base of support that would produce greater momentum in the upper body. He also altered the angle of his arm at release from 70 to 30 degrees by throwing his lead hip forward sooner and keeping the discus "hanging back" so he wouldn't release it too early.

Was it worth it? Until the '76 Olympics, Wilkins' best toss had been 219 feet 1 inch against a world record of 226 feet 8 inches. After incorporating Ariel's suggestions into his technique, Wilkins threw the discus 232 feet 6 inches to set a new world record and win the gold medal in Montreal in 1976. He gave Ariel more than a little credit for his achievement.

The success with Mac Wilkins propelled Ariel into the sporting limelight, science division. But it was not his first success, nor has it been his last. American long jumpers have increased their distances since Ariel showed themcontrary to what they had been taughtthat the free leg is more important than the one used to push off, because it and the torso accelerate as the planted leg decelerates, and it is that acceleration that pushes the body further forward.

Women basketball players began jumping two inches higher after Ariel convinced them not to bend their knees as deeply as they had been. American

shotputter Terry Albritton had an energy shortage much like Wilkins': Instead of keeping his legs steady and using them as a foundation for the upper body, Albritton was bending the knee of his front leg, which, as Ariel described it, "was like trying to throw from a trampoline or shoot a cannon from a canoe." A month after talking to Ariel, Albritton went on to set a new world record with a put of 71 feet 81/3 inches.

For the most part, Ariel has had better luck dealing directly with athletes than working through their coaches. As director of biomechanics and computer science for the United States Olympic Committee, Ariel has had numerous occasions to work with coaches and see his suggestions ignored.

In one case, he tried to convince the hammer-throw coach that the athletes were staying too long on one foot and leaning too far forward, forcing them to work against the body's center of gravity. Says Ariel, "I had documented this. But coaches resisted. They have their own ideas formed over 20 or 30 years and won't change or accept the new technology. They are driving the Model-T Ford in the jet age, are into witchcraft, working on a random system, instinct, old wives' tales."

Luckily, there are some coaches who are willing to give the new methods a try. Steve MacFarland, a young Olympic diving coach, tells how Ariel showed his divers that accelerating their arms during the takeoff of a backward dive plays a big role in distributing energy to the board and allowing for a higher spring. MacFarland was not only sold on Ariel's technology, he was deeply impressed by Gideon's devotion to his work, pointing out how the computer wizard donates his time to the Olympic Committee (he is only paid expenses), is always available for consultation, and, despite a busy schedule of paying clients, will give out his advice at no charge to those short of funds.

riel's success with Olympians
-particularly discus thrower
Mac Wilkins-gave him an
extra fillip of satisfaction be
cause he was once an ath
lete, too, a discus man, a fact that un
doubtedly is a motivating force in his
present enterprise. A citizen of the
United States for the past 14 years,
41-year-old Ariel was horn and raised in
Israel. A clumsy youth who ached to
excel in sport, he learned to throw the

USAIR MAGAZINE October 1980