USC
About this Article
Written by: Adrian Lim
Written on: October 24th, 2004
Tags: sports & recreation, ergonomics
Thumbnail by: Adidas-Salomon
About the Author
Adrian Lim was a junior who studied Biomedical Engineering with a Mechanical Engineering emphasis at the University of Southern California in the fall of 2004. In addition to an interest in traveling abroad, he also likes the beach, the Corrs and most things related to New Zealand.
Also in this Issue
Biodiesel: A Realistic Alternative?Written by: Shelley Howard
Engineering Water: Finding Solutions to a Drying WellWritten by: Cindy Goh
Medical MacGyversWritten by: Alexis Seegan
Michelangelo's Motion PictureWritten by: Vrunda Rathod
The Botox Lowdown: Science, Safety, and SuccessWritten by: BJ Gill
Stay Connected

Volume VI Issue II > Getting the Boot
Beneath even the biggest soccer stars is a pair of shoes designed and tested by engineers to push the limits of the game. The soccer boot (the traditional name for a soccer shoe) has evolved a great deal in form and function, particularly in the past few decades. To keep up with the sport's growing demands, industry has introduced a plethora of new designs and materials. With hi-tech sensors and computers, engineers analyze the challenges faced by athletes in match conditions. The sophisticated testing methods employed by today's largest shoe manufacturers allow engineers to design innovative boots that aid the athlete, improve performance, and drive the sport to new heights.

Introduction

The 2004 UEFA Euro soccer tournament in Portugal showcased the talent, flair, and excitement of one of the world's most popular sports. Along with the glitz and glamour of soccer's finest stars, discerning spectators saw the latest in cutting edge technology. The soccer boot (the traditional name for a soccer shoe), which serves as the primary medium linking a player to the turf and the ball, could arguably be called the single most important piece of equipment in the sport. For this reason, companies annually invest millions of dollars and spend thousands of hours completing research to ensure that players receive as much of a competitive edge as possible.
Although the base design of the soccer boot has changed very little over the past 70 years [1], the modern shoe contains numerous innovations, some more visible than others, that allow a player to push beyond the normal boundaries of performance. At its core, soccer boot technology aims to improve a player's game in three major categories: movement, ball interaction, and comfort/protection. A better understanding of the significant contributions engineering has made to the sport of soccer will be gained by examining the new innovations in these three areas.

Get a Grip

As the player's primary point of interaction with the playing surface, the soccer boot must provide excellent traction. Better traction allows for greater acceleration and directional control. The innovation that allows for this traction is the cleats or studs that run along the bottom of the shoe, an improvement resulting from the demands of poor weather and field conditions [1]. Borrowing from field hockey shoes of the same era, shoemakers attached plugs of leather to the base of the shoe in the 1890's [1]. Safety rules regulating the type of materials that could be used in the manufacture of the studs required the use of leather plugs instead of more dangerous metal tacks.
Over time, as players improved and game styles changed, cleat versatility, design and placement became important areas of development. In terms of versatility, removable studs, pioneered in the 1920's [1], allowed players unprecedented control over traction capabilities. Players could tailor the stud length according to field conditions, choosing longer studs for better grip in wet conditions and shorter studs for firmer, dry surfaces. The ability to swap out studs was such a significant innovation that it remains a feature on many high-end soccer boots manufactured today.
Cleat design focuses mainly on the shape and material used in construction. While older shoes used hardened, leather studs, modern shoes commonly feature durable, tough plastics or metals such as steel or magnesium, which have the benefit of low weight. Plastic cleats have the advantage of being directly molded from the same piece of material as the sole of the shoe, which reduces manufacturing costs. Commonly, studs incorporate a circular design with a wider diameter near the sole and a slightly smaller diameter closer to the point of contact with the ground. Alternatively, some companies have adopted more radical stud designs such as angular, teeth-like cleats, called blades, designed to provide more aggressive grip in predetermined positions.
Cleat placement also contributes significantly to the functionality of a soccer boot. A standard arrangement of four studs in the forefoot and two studs in the heel allows for even weight distribution and has been the style of placement most common since the advent of studs. Using advanced pressure sensors and computers, however, modern day researchers for numerous shoe companies have discovered other arrangements suited to better performance. Circular patterns optimize omni directional acceleration [1] while laterally arranged studs provide an advantage in directional changes to the left or right. This means that in addition to improving traction, cleat arrangement can also affect a player's agility.