The serve and volley of tennis innovation

Wimbledon fortnight has just passed (and what a men's final!). This Kat takes a break from practising her serve, to explore the evolution of the game of lawn tennis, from its invention in the 19th century to the modern day.

Invention of lawn tennis and wooden rackets

The admirably named Major Clopton Walter Wingfield is considered by many to be the inventor of lawn tennis. Following a successful military career, the Welsh Major set about developing an outdoor version of the popular indoor game of Real (court) tennis that could be played on the ubiquitous croquet courts of the wealth elite. Real tennis, which harks back to medieval times, is played on inside courts with hard cork tennis balls. A tennis game that could be played on a croquet lawn, as opposed to inside courts, was made possible by the development of new rubberised, bouncy tennis balls. 

Major Wingfield came up with a game that he called "Sphairistike" (from the Greek "sphari", meaning ball). In the words of an information pamphlet at the time, the new game provided "an opening for the exhibition of much grace and science". In the 1880s, Major Wingfield was granted both a UK and US patent (US157259) for his lawn tennis court arrangement.

Wingfield's lawn tennis court 
(US157259)

The first lawn tennis rackets were adapted from the rackets used in Real tennis; slightly lop-sided with a small head. The first Wingfield lawn tennis rackets had frames of solid beech or ash wood strung with gut (animal intestine). As the game became more popular, the rackets evolved to have a slightly larger head (65 sq inch), closer to the shape of modern tennis rackets. 

The size of the racket head of these wooden rackets could not be increased too much. Larger headed wooden rackets would have lacked the strength and stiffness to support the strings under tension. Wooden rackets were also water absorbent, which could lead to warping and unpredictable performance. Despite these disadvantages lawn tennis rackets remained largely unchanged for 100 years. Developments in material science were needed to advance the sport.

Metal rackets

Following the invention of metal alloys, many attempts were made to make an affordable and usable metal tennis racket. Metal had the advantage of being lighter than wood. However metal frames were difficult to string without bringing the high tension strings into contact with sharp edges in the frame (and thus causing rapid degradation of the strings). 

The problem of how to string a metal frame was finally solved by the French tennis player Jean Rene Lacoste in 1953. Lacoste patent GB955733 claims a racket in which the strings are looped around the frame as opposed to being strung through it. Lacoste licensed his invention to the Wilson Sporting Goods Company, which made the racket design a commercial success, branded as the T-2000. Jimmy Connors famously won Wimbledon with the T-2000 in 1974 and 1982.

Lacoste looping (GB955733)

The T-2000 still had a relatively small head compared to modern day rackets. The first so-called "over-sized" racket to gain popularity was the aluminium framed Howard Head racket. The Howard Head had a frame that was 50% larger than standard 65 sq inch wooden rackets. A larger head size provided a larger "sweet spot", making the game easier to learn for beginners. The Howard Head racket was patented (GB1507887) and was successfully commercialised by Prince sporting goods (although notably the Howard Head patent was invalided in Germany, in view of the prior public demonstration of the Bentley Fortissimo racket, another over-sized racket). 

Despite the commercial success of the Howard Head, wooden rackets continued to dominate the sport at the professional level. Whilst, metal-framed over-sized rackets were easier to play with at an amateur level, the higher power of play at the professional level, combined with the flexibility of the metal frame, made it difficult for players to control the direction of the shot. The low dampening effect of metal-framed rackets upon impact with the ball was also thought to considerably increase the risk of tennis elbow. 

Composite rackets

Dunlop composite frame (GB2015886)

The commercialization of carbon fibre materials in the 1970s heralded a new era of tennis racket design. Modern tennis rackets are formed of a composite material of carbon fibres in an epoxy resin matrix. Early examples of composite rackets include the Dunlop Max200G (GB2015886), which was the first composite racket to be produce with injection moulding. The Max200G was favoured by both John McEnroe and Steffi Graf. Composite materials have a high strength to weight ratio and can be used to produce rackets that are considerably lighter than their wooden forbears. Modern composite rackets are about 250g in weight (less the half the weight of the old wooden rackets). The lighter weight of composite rackets allowed the production of rackets with larger heads. A dramatic increase in racket head size lead the International Tennis Federation to introduce a limit of 29 × 12.5 inches on racket head size. 

The decreased weight and increased size of the tennis rackets changed the game from one primarily focused on technique to one dominated by power. Lighter rackets can be swung with greater speed, leading to a more powerful impact with the ball. It is also easier to generate top-spin with modern day composite rackets. The larger head size of composite rackets also increases the sweet spot size, making it easier for a player to control the ball, so that even a beginner can hope to hit the ball in the right direction. Composite rackets also retain their stiffness for longer than do metal rackets and have a higher dampening effect, lowering the risk of tennis elbow.  

The carbon fibres of composite rackets can also be woven into a variety of patterns that influence the characteristics of the frame. Rackets can thus be tailored to a player's style. Unidirectional fibres that extend along the main axis of the racket, for example, can be used to produce high bending stiffness. Additives can also be added to the epoxy resin matrix. Many professional players, for example, use rackets containing Kevlar for increased stiffness.

For tennis related IP and innovation, take a look at last year’s Guest post on IPKat: Tennis in 2018: Did intellectual property hold serve?