UNDER THE MICROSCOPE:ALTHOUGH I haven't played golf for several years, I am preparing to start again and I was looking through my golf bag. I will have to buy a new driver. My current one has a stainless steel shaft and stainless steel faced impact surface on the head and is difficult to use effectively. I notice that all drivers for sale now have huge heads compared to my old driver. Also, the most technologically advanced of the new drivers, sported perhaps by the majority of amateurs nowadays, are thin-faced titanium drivers. These are popular because they drive the ball further. However, these new-fangled drivers come with a built-in disadvantage – they may damage your hearing! It is all explained in a recent article by MA Buchanan and colleagues, British Medical Journal( BMJ), Vol 337, pp1437-1438, December, 2008.
The coefficient of restitution (Cor) of a golf club is a measure of the efficiency of energy transfer between the golf club head and the golf ball. The upper Cor limit for a golf club in competition is 0.83, which means that a golf club head striking a golf ball at 100km per hour will cause the ball to travel at 83km/h. The thinner faced titanium clubs, such as the King Cobra LD, have a greater Cor and deform more easily on impact – the “trampoline effect” – not only driving the golf ball further, but producing a louder noise than the stainless steel golf drivers. The King Cobra LD had a Cor greater than 0.83, but I understand that the current King Cobra drivers are allowable in competition and have been tuned to reduce noise.
The BMJpaper describes a man aged 55 who presented to an eye, ear, nose and throat clinic with tinnitus and reduced hearing in his right ear. He had been playing golf three times a week for 18 months using a King Cobra LD titanium club and he described the noise of the club hitting the ball as "like a gun going off". He found the noise so unpleasant he was forced to discard the club. After detailed examination it was concluded that his hearing impairment was due to the noise of the golf club hitting the golf ball.
The researchers did an internet search of reviews of the King Cobra LD club. Typical comments were: “It can be heard all over the course, it is mad!” and “This is not so much a ting as a sonic boom which resonates across the course.”
Buchanan and colleagues measured the sound levels produced by six different titanium golf drivers and six standard thicker- faced stainless steel drivers, at a distance of 1.7m from the point of golf club impact with the ball, the average distance between the golfer’s right ear and the point of impact. The thin-faced titanium clubs were all louder than the stainless steel clubs. The King Cobra LD was not the loudest – that distinction went to the Ping G10.
The BMJpaper concludes: "Our results show that thin-faced titanium drivers may produce sufficient sound to induce temporary, or even permanent, cochlear damage in susceptible individuals. The study presents anecdotal evidence that caution should be exercised by golfers who play regularly with thin-faced titanium drivers to avoid damage to their hearing."
So, golf may be more hazardous than commonly thought. You can strain your back from repeatedly subjecting it to the forces involved in swinging a golf club. You can develop a form of tendonitis known popularly as golfer’s elbow. You can damage your hearing from listening to your fancy titanium driver with the humungous head, making it less likely that you will hear the frantically shouted “fore” the day the ball from a miss-hit drive is speeding at 150 miles per hour towards the middle of your forehead!
Finally, a golfing joke. A 75-year-old man whose only pastime is golf arrives home from the course one day and announces that he will never play again because he can no longer follow the flight of his ball due to deteriorated eyesight. His wife says: “I know an 85-year-old man who plays golf regularly and has eyes like a hawk. Why don’t you team up with him? He will watch out for your ball and you will be good company for each other.”
The husband arranges to play with the older man. The 75-year-old drives off on the first tee. “I’d say that’s a good one, keep an eye on it,” he says to the 85-year-old. “Not bad at all,” says the 85-year-old. The 85-year-old then drives off and they both stride together down the fairway. “Now,” said the 75-year- old, “where did my ball wind up?”
“Oh dear,” says the 85-year-old, “I can’t remember.”
William Reville is associate prof of biochemistry and public awareness of science officer at UCC – http://understandingscience.ucc.ie