Duke Researchers Analyze Special Olympics Lifters
DURHAM, N.C. – When more than 7,000 Special Olympics athletes came to central North Carolina in 1999 for the World Summer Games, Duke University Medical Center sports medicine researchers saw a unique opportunity to perform detailed, high-tech analysis of one particular group of these athletes -- the power lifters.
The results of the analysis should prove beneficial for all competitive power lifters, the researchers said. The key findings were that one of the two lifting approaches is easier on the back and that the better lifters tend to keep the bar closer to their body as they lift the weight.
"Our goal has always been to use scientific approaches to improve the performance of an athlete, while at the same time reducing the chances of injury," said Rafael Escamilla, research director of the Michael W. Krzyzewski Human Performance Laboratory (K Lab) at Duke and former world champion power lifter.
"There are very little data out there on athletes who compete in the Special Olympics, so the 1999 Games gave us a great opportunity," Escamilla said. "What we gained from our analysis should not only help lifters in future Special Olympics, but should also be of benefit to all lifters."
The results of Escamilla's analysis appear in the August 2001 issue of the journal Medicine and Science in Sports and Exercise, which is published by the American College of Sports Medicine. The study was supported by Duke's division of orthopedic surgery and the K Lab.
Escamilla's team focused on the dead-lift, which is one of three lifting events designed to challenge a lifter's unadulterated brute strength. As the name suggests, it involves lifting a "dead" weight, usually two to three times the weight of the athlete. Gripping the barbell, which sits flat on the floor, athletes attempt to lift the weight until they are standing upright with their shoulders back with knees and elbows locked.
There are two approaches to lifting the weight: conventional and sumo. In the conventional approach, the lifter's legs are closer together, the feet point forward and the arms are positioned outside the legs. For the sumo style, the legs are farther apart, the feet are turned out and the arms are positioned inside the knees. In general, lighter lifters tend to use the sumo approach while larger lifters tend to use the conventional style.
For the Duke study, Escamilla's team trained two synchronized high-speed video cameras on a group of 40 power lifters -- equally divided between sumo and conventional styles -- randomly selected from the more than 150 competitors. The cameras took 60 frames per second throughout the duration of each lift.
When the games ended, the researchers took their hours of videotape back to the laboratory, where the moving images were converted into digital data. A computerized motion analysis system then turned each athlete into a stylized "stick figure" with all of the important joints and bones highlighted. As the stick figures moved on the screen, the researchers were able to calculate the forces and torques experienced throughout the body at key moments during the competition.
"Analysis of the dead lift shows that the sumo style appears to be safer for the lower back; on average, the backs of sumo lifters experienced 10 percent less stress than their conventional counterparts," Escamilla explained. "By comparing the high-skilled lifters with the low-skilled, those who performed better tended to keep the bar closer to their body during the lift and maintained a more upright trunk position."
While neither sumo nor conventional style dominates in the competitive ranks, Escamilla pointed out that the relative foot positioning and hand spacing are important to successful lifts, adding that the general approach is to try to keep the weight as close to the body as possible.
"There are a lot of little things these Special Olympics athletes can do to improve their performance and lessen their risks of injuries," Escamilla said. "We plan to distribute simple tips at future competitions based on what we've learned. In many cases, the coaches for these athletes are very well-meaning, devoted and loving volunteers, but they are not experts in power lifting. We just want to help them out."
Escamilla is no stranger to Olympic sports analysis. He performed similar examinations of elite tennis players during the 2000 Summer Olympics in Sydney, Australia, as well as an analysis of the pitching mechanics during the baseball competition of the 1996 Summer Olympics.
The Special Olympics is an international, year-round program of sports training and competition for individuals with learning disabilities. The 1999 Special Olympics World Summer Games were held June 26 to July 4 in North Carolina's Triangle region of Raleigh, Durham, Cary and Chapel Hill. The next Special Olympics World Summer Games will be held in Ireland in 2003, the first time the event will be held outside of the United States.