Study finds the bulk of shoes’ carbon footprint comes from manufacturing processes.
Two MIT graduate students who studied the body movements of 14 golfers have found that shoes, like clubs and balls, play a significant role in a player's game.
Among their suggestions:
Shoes that help beginners maintain a body position that is more conducive to a good swing.
Different spike patterns and flexibility characteristics for the left and right shoes to make a player more stable and perhaps help the golfer's game.
The work, by Marc Tamres and Gerald Koenig of mechanical engineering, was based on a biomechanical analysis of how the body moves through the golf swing.
"Traditionally the golf shoe has been designed for fashion rather than performance," said Mr. Tamres, who noted that in the past most golf shoes were simply dress shoes with spikes. But over the last several years golf has become a performance sport with large purses and tournaments. As a result, Mr. Tamres said, "research has been done on designing better golf clubs and balls, and now footwear."
Tamres and Koenig got involved in this research when the Foot-Joy Corporation approached their advisor, Robert W. Mann, Whitaker Professor Emeritus of Biomedical Engineering. "Foot-Joy was interested in getting a biomechanical analysis of the golf swing to determine the role of the shoe," remembers Mr. Tamres.
The two decided to take on the project-funded by Foot-Joy-with the goal of learning more about how the body moves in general. "We wanted to study human movement as applied to a sport-in this case, golf," Mr. Koenig said.
The Koenig/Tamres work was the first comprehensive analysis of a sport to use a system developed by Professor Mann and his students that allows scientists to measure the movements and forces occurring during an activity-like the golf swing-at any point in time. The TRACK system (for telemetered real-time acquisition and computation of kinematics) "provided us with a great deal more quantitative data than other motion-analysis systems," Mr. Tamres said.
If you'd poked your head into MIT's Eric P. and Evelyn E. Newman Laboratory for Biomechanics and Human Rehabilitation earlier this year, you might have seen the TRACK system at work.
At first glance you'd have seen a golfer hitting balls into a bright green net. A closer look and you'd have noticed that the golfer was fitted with small arrays (groups of light-emitting diodes) at different intervals along his body and on his shoes and club.
Throughout the player's swing each array emits infrared light that is captured by two cameras. That data in turn is sent to a computer that analyzes the signals to "give the position and orientation in space of each [array] at any moment in time and correlate this with the forces and other dynamics at any given point in the swing," Mr. Tamres said. From there, Tamres and Koenig could relate these dynamics to the swing.
The TRACK system is also integrated with a force plate; in this case the plate was covered with a patch of artificial turf that the golfer stood on. The force plate allowed them to measure the complete dynamics of the swing, including weight shifts for each foot. In addition, Tamres and Koenig mounted strike plates to the club to see where the club hit the ball (an indication of how good the swing was), asked the golfer to rate his swing, and videotaped each trial for a further visual record.
"We tried to get a very comprehensive data set because everything could be a clue to what's going on," Mr. Tamres said.
Tamres and Koenig ran tests with 14 male golfers, including two controls "who helped calibrate the system, determine how many arrays a player could wear comfortably, and generally see what effects the overall experiment may have on a golfer," Mr. Koenig said.
The 14 golfers-all right-handed-included students and coaches from the golf teams at MIT, Harvard, and Boston College, as well as two Foot-Joy employees. They represented three handicap groups, or levels of play. "We wanted to see if there were any trends among low-handicap players [better players] that separate them from high-handicap players," Mr. Koenig said.
Each player went through two sets of tests: one concentrated on the foot and ankle, the other tracked overall body movement. For these tests players used three different clubs-a driver, 3-iron, and 7-iron-to determine how they affected the swing. All together, the tests took three hours per subject (including warm-up time).
To analyze the data they collected, Koenig and Tamres developed an algorithm to compare different golfers within the same handicap group and across the three groups. This month they presented their findings at a formal workshop.
In their study of overall body movement, the two made three general conclusions. First, they found only subtle differences between swing patterns for the different clubs used although, as is intuitive, a heavier club hit the ball with more force.
They also noted a significant difference between how high- and low-handicap players "coiled" their bodies in preparation for the swing. "You can obtain more power out of your swing the tighter you wind it," Mr. Koenig explained. "We found that better players made better use of their bodies [to get this effect]. Less-skilled players appeared to inhibit their coiling-it was almost like they were trying to prevent themselves from coiling."
Koenig and Tamres also made a discovery that surprised them. "You might expect that one of the characteristics of a good player is a very consistent swing, and that a player that's not as good might be more sporadic," Mr. Tamres said. But he and Mr. Koenig found no evidence of any differences in consistency between the different handicap groups. He noted, however, that "although better players may not be more consistent, they're doing more of what's conducive for a better swing than [other] players."
The two were able to make several other observations directly related to the golf shoe. For one, said Mr. Koenig, "we were able to measure the two feet separately [during a swing] and quantify differences between them." As a result, he said, "the left and right shoes should be designed differently."
Variables to consider in developing these shoes include stiffness characteristics (Koenig and Tamres identified general areas that should be strengthened and areas that should be more flexible based on the forces generated) and the placement of spikes (they found areas where spikes may make the player more stable).
The two also found significant differences between what was happening at the feet of better players and those of players with higher handicaps. Concluded Mr. Koenig: "perhaps a person with a higher handicap should have a different shoe design than a better player."
To that end Mr. Tamres said that shoes could be specifically designed for players with higher handicaps "to help them induce the proper movement." With such shoes, Mr. Koenig said, "if a player moved in a manner that didn't feel comfortable, he would have feedback to correct his movement." Once the player got better, he could go on to a higher-performance shoe.
Koenig and Tamres note that this study is one of the first to follow a moving shoe (each shoe was equipped with two TRACK arrays). As a result, it gave them a great deal of new information "that could be applied across the board-to all shoe designs-even though we only looked at one type of shoe," Mr. Koenig said.
So do Koenig and Tamres believe that golf shoes affect a player's game? "We think that a properly designed shoe will make a difference," Mr. Koenig said, "but it's difficult to quantify. If a person feels it's helping him, and he's more comfortable, there's a positive psychological effect. And a player's psychology plays an important role in his performance."
A version of this article appeared in the December 2, 1992 issue of MIT Tech Talk (Volume 37, Number 15).