The aim of the study was to investigate the noise exposure for different technical officials during a major badminton tournament.
Individual noise exposure for technical officials was measured during the 23rd BWF World Championship, 2017 in Glasgow, Scotland during all days of the tournament.
Umpires and on-court-doctors had equivalent noise exposure, when working longer shifts, that exceeded the exposure limit according to the EU 2003/10/EC noise directive. Exposure limits regarding impulse sound was also exceeded during several work shifts during the tournament.
Technical officials are exposed to noise levels that exceed current occupational health leg-islation within the EU, and may therefore be at risk of developing hearing related disorders. It is of high importance for the organizers of sports events to reduce the noise exposure for the technical officials by scheduling shorter work periods, but also by providing individual hearing protectors.
During major sports events athletes prepare themselves to perform at their best. The environment around the competitions are often optimized to support the athletes before and during the games. Studies have shown that mental readiness is one major key component to whether the athletes will succeed or fail during a competition . This mental readiness may be disrupted, and thus affect the athlete’s performance negatively during competition. Well-developed routines with a good organization have been shown to be of high importance for peak performance by the athletes during major competitions .
The interest for the major tournaments is high from both media and spectators, which puts a high pressure on the athletes. However, the same demands also apply for technical officials, such as referees and umpires. Similar to athletes, the technical officials are expected to perform at their best during the games, since a poor performance may have a negative impact on the outcome of the game. Several external factors may affect the technical official’s performance, such as the possibility to recuperate and prepare mentally between different matches. Similar to athletes, a poor organization of the tournament may also affect the technical officials negatively. During the games, factors such as the behavior of athletes, coaches and the spectators may disrupt and affect the technical official’s performance. Research regarding technical officials work conditions during longer tournaments is to our knowledge lacking.
One major factor that may affect the technical official’s performance is the actual working condition before, during and between games. Organizers of most sport tournaments usually aim for having as much spectators as possible. A high attendance is highly associated with higher noise levels, especially if the event is located indoors. Noise is one important factor to consider during tournaments, since noise-induced hearing loss (NIHL) and other hearing related ill health such as tinnitus  are well-known risks when working in noisy work environments. The severity of the hearing damage mainly depends on the intensity and the exposure time of the noise.
Among patients who report having tinnitus, about 80% of those individuals also reported having hearing loss  In the general population studies have shown that about 12% to 30% report having tinnitus and that the prevalence increases with age . Sports officials exposed to whistle noise during games has been shown to report higher prevalence of hearing disorders such as hearing loss and tinnitus prevalence compared the general population.
NIHL is an irreversible damage to the hearing. The severity of the damage mainly depends on the intensity and the exposure time of the noise. Beside the risk of developing hearing loss, high noise exposure may also increases the risk of developing tinnitus symptoms which is a common disorder often seen together with hearing loss . Since it not possible to cure hearing loss and tinnitus, early detection of hearing loss is highly important to prevent further hearing loss or severity of tinnitus.
Occupational noise exposure is today the major cause of NIHL . To prevent the development of NIHL, a number of different preventive measures are available. Firstly, it is important to reduce the number of noise sources at a work place , but also to actively work to lower the noise emission from the different sources[7,9]. Beside measuring noise exposure in terms of equivalent noise exposure, high impulse sounds is also of interest . To further reduce the noise exposure it is also important to organize the work to minimize the noise exposure time for each worker.
Even shorter work periods with high noise exposure may cause a temporal hearing threshold shift (TTS)  which in some studies have been shown to predict NIHL . Longer works shifts or shorter work shifts with rather high noise exposure need to be followed by a longer recuperation period with little or no noise exposure . It has also been shown that noise levels not considered as harmful in terms of the sound level, due to an accumulative effect during a work week, may cause a disturbance in the central auditory system .
An important factor in reducing the noise exposure is investigate the noise exposure during specific work periods by use of appropriate sound level meters . To early detect NIHL regular audiometric screenings need to implemented at work places with high noise levels .
Sport events, especially indoor events, are typically not seen as high-risk work places regarding noise exposure. The responsibility of the work environment may be somewhat unclear during the event. Different sport events may also include a large number of volunteers working, which complicates the responsibility of the organizers.
The work time for technical officials during sport events can vary between short workdays with few work hours up to work shifts longer than ten hours, often with limited possibilities to rest and recuperate between work shifts and workdays.
The contextual settings for different sport events may also differ to a high extent. Golf and tennis tournaments are often characterized by having a rather silent audience when the athletes perform on the court or on the golf course. Other sports, such as basketball and hockey are characterized by having a noisy audience when the actives are performing. Studies  have shown that the sound level during basketball games in the US may reach peak sound levels around 120-130 dBA for various employees sitting close to the basketball court.
Studies on the noise exposure for spectators on intercollegiate basketball games showed that the participating spectators in the study was exposed to LAFmax values around 119 dB in average. The equivalent noise exposure during the games were around 98 dB . Audiometric tests before and after the game were also conducted showing that the participants had a temporary threshold shift in puretone thresholds as well as a reduction in their optoacoustic emission . Similar results regarding noise exposure have also been observed for various employees during hockey games in the US with peak levels varying between 105-124 dBA during the games . Other studies have also shown that the noise level may differ from 81 to 96 dBALeq and 105-124 LAFmax depending on where in the arena the individual is positioned during the venue . The size of the crowd may also be of importance, but also the characteristics of the crowd and the game may also have an effect on the noise level .
Technical officials are in some sports often volunteers with different work tasks during the sport event. Umpires and “on-court-doctors” are two positions within the concept of technical officials during badminton tournaments. Considering the work carried out by the technical officials, the organizers of a sport event should be considered as an employer. This make the organizers responsible to follow current work legislation regarding occupational health and safety, which includes noise as a potential risk factor. The sound level is often high during different sport events, which may increase the risk of hearing disorders. However, further knowledge is needed regarding noise exposure during sport events with many workdays.
The aim of the study was to investigate the noise exposure for different technical officials during a major badminton tournament.
Technical officials at a major badminton tournament (23rd BWF World Championship, 2017 in Glasgow, Scotland) were asked on location to participate in the study by one of the authors.
The Helsinki Ethical Declaration guidelines were followed , in that the participants were informed that participation was strictly voluntarily and that they could end their participation at any time with no explanation needed. All participants were informed that all data would be presented anonymously. The noise data collection method has been used in previous studies without any complications [21-23].
Seven male and one female umpire volunteered to participate in the study. The work hours for the umpires were scheduled for each day of the tournament. Two male oncourt-doctors also participated in the study. The on-courtdoctors were at all times available during match time for treatment and handling of acute injuries on the playing courts.
Two Brüel and Kjaer 4445 noise dosimeters were used in this study. The participants wore the noise dosimeter during their whole work shifts with the microphone mounted on the shoulder, see Figure 1.
Figure 1 Microphone position on the participants.
The noise dosimeters were calibrated before the tournament using a Brüel and Kjaer Sound Calibrator – Type 4231. The noise dosimeters were set to log dBALeq, LAFmax and dBCpeak values each 30 second. The range of the noise dosimeters were set to a measurement range of 70-140 dB with a C-weighted peak range of 40 dB above the measurement range. Time weighting was set to Fast.
Each noise dosimeter was started at the beginning of each day of the tournament. The noise dosimeter used by the umpires was started at the beginning of the first work shift for the first umpire of the day. During day one to four one umpire wore the noise dosimeter during the whole working day, including pauses. During day five to seven, due to fewer playing courts, the umpire on duty wore the noise dosimeter. At the end of each work shift, the noise dosimeter was switched to the umpire working the next shift. This was repeated until the end of each tournament day. This resulted in 15 work shifts in total, with sound level measurements for the participating umpires during the tournament. The on-court-doctors wore the noise dosimeter the whole working days, thus resulting in seven full days of sound level measurements.
Noteworthy is, that the noise dosimeter was running continuously without being stopped when switched between umpires. Due to the position of the microphone and the switching between umpires, the umpires climbing up and down the umpire chair etc. the microphone was occasionally affected during short periods of the measurement, which resulted in some overload registrations in the sound level measurement. All sound level data has therefore been thoroughly investigated and periods of time that indicate that kind of sound level overload have been excluded from the data. Approximately 2.5 minutes of the sound level data in average were excluded from each of the sound level measurement for the umpires except for day three.
During the third day of the tournament the microphone worn by umpire two was in a position that resulted in overload data for one hour and twenty-four minutes. This time was excluded from the data, see Table 3.
To evaluate the noise exposure for the technical officials, the European Union occupational exposure limits according to EU 2003/10/EC  was applied, and the Swedish occupational exposure limits for dBAMAX was applied in the present study .
The EU 2003/10/EC directive have three different levels that require actions by the employer if the noise levels are exceeded. The “lower exposure action value” and the “upper exposure value” are the first two levels. It these levels are exceeded the employer is required to actively try to reduce
the noise exposure and protect the workers with preventive measures but also provide hearing protectors. The third level “Exposure limits” are levels that under no circumstances may be exceeded. See Table 1 for detailed sound level limits according to the EU directive. Furthermore, some European countries such as Sweden, also have occupational exposure limits for A-weighted maximum sound levels . The different noise exposure limits according to legislation are presented in Table 1.
Table 1 European Union occupational exposure limits according to 2003 noise directive  and Swedish occupational exposure limits  for dBAMax.
Furthermore, the noise criterion level used in this study was set to a 3 dBA exchange rate as used within the EU 2003/10/EC . Depending on exposure time, the maximum work time for different equivalent noise exposure is presented in Table 2.
Table 2 Noise Exposure Limits with Criterion Level = 85 dBA with an exchange rate of 3dB according to the EU 2003/10/EC .
The tournament venue was the Emirates Arena in Glasgow, Scotland. Spectator attendance during the different days of the tournament is presented in Table 3. Figure 2 illustrates a modified layout of the arena (Team Managers Guide, 2017). Areas marked with grey striped circles illustrate areas where the umpires mostly were positioned between the courts during umpiring. In each match the match umpire is sitting on the umpire´s chair about 150 cm above the floor on one side of the net, while the other umpire (the service judge) is sitting on a chair on the floor on the other side of the net.
Areas with black circles illustrates the areas where the on-court-doctors were most often positioned during their noise exposure measurement, sitting beside the courts next to one of the referees to be ready to go on court. The audience is located behind the on-court-doctors and the referees.
When an umpire or an on-court-doctor was not umpiring/ working, he/she spent the time resting in the Technical officials lounge (light/dark grey box), next to the warm up courts, or watching matches on the spectator seats.
Figure 2 The venue layout of the Total BWF World Championships 2017.
Figure 3. Overview of the level of fluctuations during a noise exposure measurement. The blue line illustrates dBALeq, the green line illustrates LAFMax and the red line illustrates dBCPeak.
The noise exposure measurements for the technical officials show that during the last three days of the tournament the work shifts were shorter for the umpires compared to the oncourt-doctors. The first four days the exposure time was similar for both umpires and the on-court-doctors, see Table 3.
During the tournament umpires and on-court-doctors, when working longer shifts, were exposed to noise levels exceeding the lower action value, upper action value and the exposure limit value regarding the dBAleq, see Table 1. The highest exposure regarding dBAleq was observed for on-court-doctor #1 during day seven with an exposure of 89 dBAleq. With a criterion level of 3 dB as used within the EU 2003/10/EC24 a work time with this exposure need to be approximately less than four hours, see Table 2.
The noise exposure measurements show that legislation regarding impulse sounds (dBCpeak) was also exceeded during different work shifts. Umpire #5 and on-court-doctor #1 during day six of the tournament were both exposed to impulse sounds above 140 dBCpeak, which exceeds the exposure limit. For two umpires the upper action values were also exceeded regarding dBCpeak impulse sound with sound levels above 137 dBCpeak during day one, two and seven.
When applying the Swedish noise exposure limits of 115 dB LafMax on the noise exposure data, it is shown that limit is exceeded for eight work shifts during the tournament . The highest dBAMax value 120.6 dB was registered during umpire #2´s work shift during day three.
In overall, the results indicate that the umpires to a higher extent are exposed to more impulse sound compared to the on-court-doctors during the seven-day tournament. The umpires were exposed to dBCpeak impulse sounds above the lower action limits on five occasions. For the on-court-doctors the lower action values were exceeded on two occasions. The equivalent noise exposure dBALeq was rather similar between umpires and the on-court-doctors during longer workdays.
In figure 3 a measurement from On-Court-Dr #1 on day 7 is illustrated. The last 3h and 35 min of the work shift (8h 26min) was used to illustrate the level of noise fluctuation. The selected part of the exposure measurement when recalculated showing that during this last time period of the work shift, the exposure regarding dBALeq was 90.4 dB, the highest LAFMax value was 110.3 dB and the highest peak value dBCPeak =was 130.1 dB.
Table 3. Noise exposure measurement data (dBALeq, dBCpeak, LAFmax, measurement time and excluded time due to overload) separated for umpires and on-court-doctors, and day of the tournament. The number of spectators each day is presented in the left column within the brackets.
*EU Exposure level exceed the lower exposure action value. For dBALeq the exchange rate 3 dB is applied.
**EU Exposure level exceed the upper exposure action value.
***EU Exposure limit value exceeded. † Swedish legislation upper exposure action value and limit value exceeded
The present study shows that technical officials most days are exposed to high noise levels, regarding equivalent noise levels as well as impulse sounds. This exposure exceeds current occupational exposure limits directive set by EU 2003/10/EC . Occupational noise exposure is today the major cause of NIHL . Therefore, the technical officials may be at risk of developing NIHL and other hearing related disorders.
The directive EU 2003/10/EC  presents minimum requirements for the protection of workers hearing related health. How the preventive work should be carried out is presented in the framework directive Health and Safety at work 89/391 . These guidelines are applicable in other areas such as sport events, that traditionally is not considered as work places due to the fact that many of the workers are volunteers. Therefore, it is important for the organizer of sports events to make sure that the noise exposure levels are not exceeded for the technical officials and other volunteers.
To reduce the high noise exposure the organizers need to analyze which factors that contribute to the high noise exposure. Several different preventive measures are available to reduce the noise exposure and lower the risk of developing NIHL.
Firstly, it is important to reduce the number of noise sources at a work place , but also to actively work to lower the noise emission from the different sources [7, 9]. This may be problematic in sports events, since a high attendance of spectators is often desirable. Therefore, factors that may be of importance for the organizer is to further investigate the layout of the arena. To start the preventive work and to identify possible preventive measures against high noise levels, the organizers need to ask questions such as; how many spectators will there be, how near the actual court will the spectators be located, how should the sound system be used, where should the technical officials be placed?
It is also important to organize the work to minimize the noise exposure time for each worker. Even shorter work periods with high noise exposure may cause a temporal hearing threshold shift TTS , which in some studies have been shown to predict NIHL . Therefore, long working shifts or shorter work shifts with high noise exposure need to be followed by a longer recuperation period with little or no noise exposure . Holgers  showed that there is a strong correlation between subjective experience of TTS and noise-induced tinnitus among young children.
The registered noise exposure in the present study indicates that that it is most likely that the technical officials may experience a TTS after a day of work since the exposure in this study is comparable to the results in England and Larsen´s  study where they observed a TTS shift in the participating spectators. With this in mind, the tournament organizers should consider organizing the work so that the work shifts are shorter for the technical officials. Furthermore, as a part of the preventive work, the organizers need to provide the technical officials with a possibility to rest and recuperate in silent areas both during, between and after the work-shifts to reduce the risk of developing TTS.
Preventive measures such as noise barriers where the on court doctors are located to shield of the noise emission from the spectators may also be considered as solutions. These barriers may be dampening shields, or even booths with glass walls for high visibility. This solution may not be applicable for the umpires during the matches, since they are located in the middle of the venue.
The high impulse sounds exceeding the exposure limits particularly needs to be addressed by the organizers. If preventive measures are not possible in order to lower the impulse sounds or the equivalent noise exposure, individual hearing protectors need to be provided to the technical officials. Research has shown that hunters that fired only 1-6 shots with their hunting rifle without hearing protection had a significant higher prevalence of high frequency hearing impairment compared to hunters who had fired more shots while using hearing protectors . Since the impulse sounds cannot be predicted the hearing protectors needs to be used during all work time. Technical solutions with built-in communication in the hearing protectors are widely available, which makes communication between technical officials and the athletes possible. Noteworthy is that research has shown that the use of hearing protectors lowers with lower sound levels [28-30].
Another factor beside the risk of developing hearing disorders when exposed to high noise levels, is how noise exposure may affect the technical officials cognitive functions and performance. Being a technical official during major sport events puts high demands on attention. Studies have shown that workers exposed to high noise levels have a slower response time after a workday when performing a visual attention test compared to workers with lower noise exposure and that the workers also reported being more fatigued after work [31, 32].
The high noise exposure may therefore put a high cognitive load on the individuals, which in turn may reduce their performance as well as increase the experienced fatigue during and after the game. The impulse sounds may also act as a distractor for the technical officials, since unexpected sounds that deviate, affect our attention and may thus impact negatively on the individuals performance . The human cognitive functioning is designed to have the ability to inhibit stimuli that are not important for the current work task. However, humans cannot block all stimuli in the environment as a safety mechanism. Deviant sounds may therefore inflict a behavioral distraction that reduces the individual’s performance in terms of reaction time and reaction accuracy .
These findings, when applied to badminton technical officials, indicate that the risk for wrong decisions in matches when the cognitive load is high due to noise exposure may increase when getting closer to the final matches.
Conclusively, this study has shown that noise exposure for technical officials in badminton do exceed current exposure limits, which is in line with studies in other sports [17, 19]. To reduce these risks, the organizers of sport events need to investigate how to lower the noise levels for the technical officials, but also to protect their hearing.
Noteworthy is that not all kinds of technical officials were included in the present study due to limitation of available noise dosimeters. The noise dosimeters, used in this study, lacks the possibility to measure octave-band noise, which would have given valuable information regarding the frequency characteristics of the noise exposure. Further studies should include full-time noise exposure measurements with more participants, using both personal carried noise dosimeter as well as stationary class 1 sound level meters to obtain more detailed information regarding the noise exposure.
Hearing related disorders was not investigated in this study on noise exposure, however the noise exposure data indicate that the technical officials are at risk of developing hearing disorders. Therefore, future studies should address this question more in depth with use of either subjectively rated hearing status or by audiometric tests.
To further understand the complexity of the work environment and how it may affect the technical officials overall well-being in terms of stress and fatigue, experienced stress, experienced fatigue and recuperation after a day of work should also be included.
Long-term measurements of the umpires heart rate would also give further knowledge whether the noise exposure affect their heart rate and their experienced stress. The cognitive effects in terms of distraction and decision making due to the noise exposure may also be of interest to study further.
These factors that may affect the technical officials health and cognitive functioning are of course also applicable on the athletes, even though the athletes most often spend less time in the venue than the technical officials. To our knowledge, there is a lack of studies concerning the athlete’s perspective regarding noise exposure, cognitive functioning and performance.
Technical officials are exposed to noise levels that exceed current occupational health legislation, and may therefore be at risk of developing hearing related disorders. It is of high importance for the organizers of sports events to reduce the noise exposure for the technical officials by scheduling shorter work periods, but also by providing individual hearing protectors.
The authors are grateful to the Badminton World Federation and to the technical officials for their participation in the study
The authors declare no conflict of interests.
This study was funded with internal means from the Departments of Psychology and Clinical Sciences at Umeå University, Sweden