Monday January 5 2009
Titanium golf drivers produce high sound levels on contact with the ball
Golfers face the risk of hearing problems if they use the latest generation of golf clubs, says the Daily Mail. The newspaper claims the “sonic boom” noise from titanium drivers had damaged the hearing of a 55-year-old man, and suggests that golfers should wear earplugs to help protect their hearing.
The story is based on a study in the Christmas edition of the British Medical Journal in which doctors describe a golfing patient’s ear damage and tinnitus. The doctors believe these problems came from repeated use of a particular titanium driver. Researchers measured the noise levels produced when a golf ball was hit with different drivers, and suggested that newer titanium clubs may expose players to quite high sound levels.
This study uses low-level evidence and appears to be written in a light-hearted spirit in keeping with other articles in the festive issue of the British Medical Journal. As the study is based on anecdotal evidence, the results should be interpreted with caution, and it remains to be seen whether hearing loss will become endemic among golfers. However, it is sensible to limit exposure to uncomfortably loud noises wherever possible.
Where did the story come from?
This research was conducted by doctors M.A. Buchanan and P.R. Prinsley and colleagues from Norfolk and Norwich University Hospital. There is no information on any external funding, and the authors declare they have no competing interests. The study was published in the peer-reviewed British Medical Journal.
What kind of scientific study was this?
This publication combines a case report of a golfer with hearing problems, and a descriptive study of noise levels attained during tests of different golf drivers.
In the case report, the doctors describe the 55-year-old man who had presented to an ear, nose and throat outpatient clinic with tinnitus and reduced hearing in his right ear. His hearing problems were diagnosed as relating to exposure to loud noise.
History revealed that the golfer had been using a King Cobra LD titanium golf club three times a week for 18 months, and he reported that the noise was “like a gun going off”. The man had stopped using the club because it had become so unpleasant. Other than this, he had no significant exposure to loud sound in his work or recreation time.
The researchers go on to discuss the energy transfer between the head of the golf club and the ball, which is measured as the ‘coefficient of restitution’, or COR. The United States Golf Association stipulates that clubs for competition use should have a COR value of 0.83 or less. A COR value of 0.83 means that if the club connects with the ball at 100mph, the ball will travel 83mph. Two of the titanium clubs tested (including the club used by the patient) had a COR value greater than 0.83.
The researchers then assessed the noise levels produced by 12 golf clubs: six thin-faced titanium drivers and six thicker-faced stainless steel drivers. They used a ‘modular precision sound level meter’ to record the noise levels generated when a professional golfer hit two-piece golf balls with these clubs.
The sound meter was positioned 1.7m away from the club as this was the estimated distance between the contact with the ball and a golfer’s ear. The researchers then presented the different noise levels from the different drivers.
What were the results of the study?
Following an examination and medical history, the doctors attributed the man’s hearing problems to exposure to noise through the use of his titanium golf club.
Their investigation into the noise produced by different types of drivers showed that the thin-faced titanium golf drivers “all produced greater sound levels than the stainless steel clubs”.
What interpretations did the researchers draw from these results?
The doctors conclude that their study provides “anecdotal evidence that caution should be exercised by golfers who play regularly with thin-faced titanium drivers” in order to avoid damaging their hearing.
What does the NHS Knowledge Service make of this study?
This small study does provide some anecdotal evidence that golf clubs produce a high level of noise when hit. There are several points to note:
- The application of these findings to the real-life golf-course situation may be limited. No detail is given about the environment in which the clubs were tested. If it was in a confined space, the direct exposure to the noise may have been greater than on an open golf course.
- There was no statistical comparison between the noise generated when using steel drivers compared to titanium ones. The trend (shown in a graph) looked to be increasing for titanium clubs, but without statistical analysis we cannot be sure that this was not due to chance alone.
- Given that all the drivers produced quite loud noises on contact with the ball, the bottom line of this study – that golfers who play regularly with thin-faced titanium drivers should be cautious about the noise exposure – sounds sensible. This is perhaps more relevant for people on a driving range who are hitting many balls in a short space of time in a confined space.
The article appears to have been written in a light-hearted spirit, and given that it is based on a single case study and statistically non-comparative evidence, the results should be interpreted as such. It is doubtful that golfers as a group are at a particularly increased risk of hearing loss.