Abstract
Background
Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported.
Purpose
The purpose of the present study was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players.
Methods
The study was a cross-sectional study conducted on Danish disc-golf players. In May 2015, invitations to complete a web-based questionnaire were spread online via social media, and around disc-golf courses in Denmark. The questionnaire included questions regarding disc-golf participation and the characteristics of injuries acquired through disc golf participation. The data was analyzed descriptively.
Results
An injury prevalence of 13.3% (95% CI: 6.7% to 19.9%) was reported amongst the 105 disc-golf players who completed the questionnaire. The anatomical locations most commonly affected by injury were the shoulder (31%) and the elbow (20%). Injuries affecting the players at the time of completion of the questionnaire had a median duration of 240 days (IQR 1410 days), and the majority (93%) had a gradual onset.
Conclusions
A 13.3% point prevalence of injury was reported. Most injuries occurred in the shoulder and elbow regions, and were gradual in onset. Injuries affecting the players at the time of data collection had median symptomatic duration of 240 days.
Levels of Evidence
3b
Keywords: Disc golf, epidemiology, frisbee golf, injury, overuse
INTRODUCTION
Disc golf is rapidly increasing in popularity as a sport and leisure activity, with an average annual growth rate of more than 11% since 2005.1 Today, the Professional Disc Golf Association (PDGA) estimates, that more than two million people around the world regularly participate in disc-golf activities,2 of which an estimated 80,000 reside in Scandinavia.3 Accordingly, the number of disc-golf courses across the world has doubled to more than 4700 between 2007 and 2014,2 further emphasizing the increasing interest in the sport.
Formalized in the 1970's, the rules and terminology of disc golf is similar to regular golf, but contrary to the use of golf balls and clubs, disc golf is played with specially designed frisbees, called discs, which are thrown aimed at elevated baskets. In disc golf, the goal is to complete a round of usually 9 or 18 baskets in the fewest throws possible, using a combination of driver-, midrange- and putter-style discs. Each course, and even each hole, presents with its distinct barriers, including terrain, elevation, curvature, obstacles and wind conditions.4,5 The player then seeks to overcome these barriers using a variety of different types of throws, of which the backhand and the forehand throws are the most common.5
Recreational disc golf appeals to a large portion of the population, as the vast majority of courses are public,4 and the sole requirement to play is a single disc that costs approximately fifteen dollars. Disc golf is a viable option for those who wants to remain active and competitive in middle age, because of the low-intensity non-contact nature of the sport and the social component, inherent to golf-type sports.6 In fact, more than 30% of the registered PDGA players are above 40 years of age.2 Disc golf also utilizes the handicap system, which facilitates high-level competition across differences in skill.
Epidemiologic knowledge regarding injuries in disc golf, however, is sparse. A related frisbee-sport, ultimate, has received more scientific attention,7-10 but as more than 40% of injuries in ultimate occurs acutely through player to player contact,10 the injury pattern is likely incomparable to disc golf. Instead, overuse injuries may be prevalent, owing to the repetitive forceful movements of throwing the discs, similar to the injury pattern of regular golf.11 One study including disc-golf players was recently conducted by Nelson and colleagues,5 revealing an 81.8% all-time prevalence of injury sustained through disc golf. However, in their study no definition of injury was provided.5 In other sports, varying injury definitions has shown to affect the number, and even location, of injuries reported.12 Therefore, more studies on injury occurrence in disc golf are needed using well-defined injury definitions.
The purpose of the present study was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players.
METHODS
Study design
The study was designed as a cross-sectional, epidemiological study. Data collection was conducted during a six-week timeframe beginning in May 2015, using a web-based questionnaire developed by the authors. In accordance to Danish legislation, no ethical approval was sought because of the observational design.
Participants
Invitations to complete the web-based questionnaire were uploaded to the website of the Danish Disc Golf Union (DDGU), and were sent by e-mail to all members of DGI disc golf organization (n = 80). Online invitations were shared on the social media site Facebook, at 17 Danish disc-golf groups. Posters were put up at five popular disc golf courses nationwide, two of which hosted the Danish disc-golf tour during the data collection phase. A participant needed to have played disc golf at least once, and be at least 18 years of age to be included in the study. Participation in the study was voluntary and all participants gave informed written consent, after reading the purposes and procedures of the study.
Data collection
The questionnaire included details of demographics (gender, age, body mass), disc-golf characteristics (e.g. hours of weekly disc-golf participation, tournament participation, experience, warm-up routines, score), and details of disc-golf injuries (e.g. anatomic region, duration/time to recovery, acute/gradual onset, treatment, workdays lost) sustained throughout the player's entire disc-golf career. Score was defined as the number of throws ± par used on a typical 18-basket course, as a substitute for handicap, as many recreational players may not be aware of their actual handicap. Participants were also asked to allocate themselves to either of four groups; “Novice”, “Amateur”, “Intermediate” and “Professional”, inspired by the PDGA player classifications. In the present study, the “Novice” group was pooled to the amateur group, since only few (n = 4) were classified as Novice. Due to the self-reporting and retrospective design of the study, only anatomic region of the injury and not specific diagnosis was collected. Prior to the study, the questionnaire was pilot-tested on a small group of disc-golf players with various disc-golf experience (range < one to eight years) and adjusted in accordance to responses. The questionnaire and database system have previously been used in epidemiologic studies.13,14
Outcome
The primary outcome measure was disc-golf injury, defined as “any physical pain or complaint sustained through disc-golf activities that resulted in full stop or modification of usual disc-golf participation, for 7 days or more”. This definition was inspired by Jacobsson and colleagues,15 and modified to include a time-loss period of seven days. The injury definition was visualized to the participant at the injury section of the questionnaire. Both data on point prevalence, defined as “currently suffering from a disc-golf injury” (current injuries), and career prevalence; “any injury previously sustained during disc-golf participation” (previous injuries, which no longer affected the player), were collected.
Exposures
The exposures hypothesized to be associated with injury risk included the following continuous variables: age (years), body mass index (BMI), experience (years), warm-up (minutes), discs carried during play (quantity), tournaments played (quantity), score (+/- 0). In addition, one categorical exposure was included: group for amateur, intermediate, or professional.
Statistical analysis
Continuous variables are presented as median and interquartile range (IQR), as several variables were non-normally distributed, tested by histograms and quantile plots. Categorical variables are presented by counts and percentages. An exploratory analysis was conducted to measure the association between exposure variables and injury status (Binary: Career injury ‘yes’, n = 41; Career injury ‘no’, n = 64). Subgroups of the exposure variables of interest were created according to terciles,16,17 and were analyzed using binominal regression. Main estimates of proportions and relative risks are presented with 95% confidence interval. All statistical analyses were performed using STATA v.13 (StataCorp LP, TX, USA), and statistically significant differences were considered at p < .05.
RESULTS
One hundred and five disc-golf players, 102 males and three females completed the questionnaire. The majority of participants (76.2%) had been playing disc golf for more than one year, 16.2% between six and twelve months, and 7.6% less than six months (they had played disc golf a median of 5.5 times, IQR 16.5). Seventy-one players (67.6%) reported membership to an organized disc-golf club, while six players (5.7%) reported previous membership. Participant demographics and disc-golf related characteristics are presented in Table 1.
Table 1.
Demographic and disc golf related characteristics of 105 Danish disc golf players. Data is presented as median and (IQR)
| All | Amateur | Intermediate | Professional | |||||
|---|---|---|---|---|---|---|---|---|
| Variable | ( n = 105 ) | ( n = 38 ) | ( n = 56 ) | ( n = 11) | ||||
| Age (year) | 29 | ( 12 ) | 27 | ( 12 ) | 31 | ( 12.5 ) | 34 | ( 13 ) |
| Height (cm) | 182 | ( 9 ) | 182 | ( 9 ) | 183 | ( 7 ) | 180 | ( 9 ) |
| Weight (kg) | 83 | ( 16 ) | 84 | ( 19 ) | 85 | ( 18 ) | 80 | ( 14 ) |
| BMI (kg/m2) | 25.5 | ( 4.7 ) | 25.6 | ( 6.2 ) | 24.9 | ( 5.4 ) | 26.2 | ( 3.4 ) |
| Experience (years) | 3 | ( 4.5 ) | 1.3‡ | ( 1.3 ) | 4§ | ( 4 ) * | 10 | ( 7 ) *† |
| Preceeding month | ||||||||
| Hours per week | 4 | ( 6 ) | 3 | ( 2 ) | 5 | ( 6.3 ) * | 6 | ( 7 ) * |
| Throws per week | 120 | ( 244 ) | 70 | ( 120 ) | 153 | ( 243 ) * | 240 | ( 340 ) * |
| Score (± 0) | 2 | ( 8 ) | 8 | ( 8 ) | 0 | ( 5 ) * | −3 | ( 5 ) *† |
| Tournaments (#) | 10 | ( 25 ) | 2 | (6) | 13 | ( 24 ) * | 100 | ( 75 ) *† |
IQR = Interquartile range, BMI = body mass index,Experience = years of disc golf participation, Score = number of throws above or below 0 on a typical 18 basket course, Tournaments = number of tournaments with entrance fee played.
p < 0.05 Different from amateur
p < 0.05 Different from intermediate
Data from 8 subjects missing (all 8 reported < 6 month experience)
Data from 1 subject missing
Forty-one players reported 55 injuries during their entire disc-golf career, which elicits a disc-golf career injury prevalence of 39% (95% CI 29.6% to 48.5%). Six players reported two injuries, while four players reported three. The 38 amateur players reported five previous and three current injuries, the 56 intermediate players reported 30 previous and seven current injuries, while the 11 professional players reported five previous and five current injuries. As one player was affected by two current injuries, fourteen players reported 15 current injuries, leading to a point prevalence of 13.3% (95% CI 6.7% to 19.9%) in the study population. Sixty-four players (61%; 95% CI 51.5% to 70.4%), including the three female players, had never sustained a disc-golf related injury.
Of all fifty-five injuries, the most common injury regions were the shoulder (31%) and the elbow (20%), as presented in Table 2. Thirty-six injuries occurred in the extremities, of which the vast majority (92%) occurred on the throwing side. All injuries at the non-throwing side (n = 3; 8%) occurred in the lower extremities.
Table 2.
Anatomic region and characteristics of all 55 disc golf injuries Data is presented as counts and (%) Data is presented as counts and (%)
| All injuries | Onset | Throwing side | Medical attention | Current injuries | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Region | (Gradual) | (Yes) | (Yes) | |||||||
| Shoulder | 17 | ( 30.9) | 12 | ( 71 ) | 17 | ( 100 ) | 5 | ( 29 ) | 7 | ( 46.5 ) |
| Elbow | 11 | ( 20 ) | 6 | ( 55 ) | 11 | ( 100 ) | 2 | ( 18 ) | 1 | ( 6.7 ) |
| Hip | 5 | ( 9.1 ) | 2 | ( 40 ) | - | - | 1 | ( 20 ) | 1 | ( 6.7 ) |
| Knee | 5 | ( 9.1 ) | 2 | ( 40 ) | 3 | ( 60 ) | 1 | ( 20 ) | 2 | ( 13.3 ) |
| Lower back | 3 | ( 5.5 ) | 3 | ( 100 ) | - | - | 1 | ( 33 ) | 1 | ( 6.7 ) |
| Upper back | 3 | ( 5.5 ) | 2 | ( 67 ) | - | - | 2 | ( 67 ) | 1 | ( 6.7 ) |
| Achilles | 1 | ( 1.8 ) | 1 | ( 100 ) | 0 | ( 0 ) | 0 | ( 0 ) | 1 | ( 6.7 ) |
| Ankle | 1 | ( 1.8 ) | 0 | ( 0 ) | 1 | ( 100 ) | 0 | ( 0 ) | 0 | ( 0 ) |
| Buttocs | 1 | ( 1.8 ) | 1 | ( 100 ) | - | - | 0 | ( 0 ) | 0 | ( 0 ) |
| Wrist | 1 | ( 1.8 ) | 1 | ( 100 ) | 1 | ( 100 ) | 0 | ( 0 ) | 0 | ( 0 ) |
| Neck | 1 | ( 1.8 ) | 0 | ( 0 ) | - | - | 1 | ( 100 ) | 0 | ( 0 ) |
| Others | 6 | ( 10.9 ) | 3 | ( 50 ) | - | - | 2 | ( 33 ) | 1 | ( 6.7 ) |
| Total | 55 | 33 | ( 60 ) | 33 | ( 92 ) | 15 | ( 27 ) | 15 | ||
The fifteen current injuries were reported to have affected the players for a median duration of 240 days (IQR 1410) prior to the point of the assessment, while a median time to recovery of 14 days (IQR 45) were reported for the 40 previous injuries. Two players reported having lost two and 10 workdays, respectively, due to injury. Of all 55 injuries, 33 (60%; 95% CI 46.6% to 73.4%) had a gradual onset, while 22 (40%; 95% CI 26.6% to 53.4%) had an acute onset. Most acute injuries occurred during drives (59%), but also falls (9%) and inaccessible throwing positions (5%) were reported. Injury characteristics of previous and current injuries are presented in Table 3.
Table 3.
Previous and current injury characteristics. Data is presented as counts and (%)
| Previous injury | Current injury | |||
|---|---|---|---|---|
| n = 40 | n = 15 | |||
| Variable | n | % | n | % |
| Injury duration (days) | ||||
| ≤ 1 month | 29 | ( 72.5 ) | 5* | ( 33.3) |
| > 1 < 12 months | 10 | ( 25 ) | 4* | ( 26.7 ) |
| ≥ 12 months | 1 | ( 2.5 ) | 6* | ( 40 ) |
| Onset of injury | ||||
| Acute | 21 | ( 47.5 ) | 1 | ( 7 ) |
| Gradual | 19 | ( 52.5 ) | 14 | ( 93 ) |
| Treatment | ||||
| Medical attention | 11 | ( 27.5 ) | 4 | ( 27 ) |
| Self-treatment | 9 | ( 22.5 ) | 6 | ( 40 ) |
| No treatment | 20 | ( 50 ) | 5 | ( 33 ) |
Self-treatment = use of painkillers, bandages, and/or exercises from the internet.
Prior to point of assessment, with the injury continuing.
Fifteen (27%) of the 55 injuries received medical attention, including physiotherapists, chiropractors and general practitioners. One injury was treated surgically. Self-treatment such as painkillers, bandages and internet-inspired exercises were used for 27% of all injuries, while nearly half (48%) of injuries received no treatment.
Less than half of the participants (43%) received technical supervision or guidance during their first year of disc golf and the median time spend on warm-up prior to disc-golf participation were five minutes (IQR 9). The median proportion of backhand, forehand, and overhead throws during the previous month were 85% (IQR 25), 10% (IQR 21) and 1% (IQR 5), respectively.
The exploratory analysis (Table 4) indicated, that players reporting scores of five or more, were less likely to report an injury, than players reporting scores of zero or less (RR = 0.37; 95% CI 0.18 to 0.76). Further, the results revealed players of the intermediate or professional group to face a significantly higher risk of injury, than players of the amateur group (RR = 2.71; 95% CI 1.32 to 5.57 and RR = 2.96; 95% CI 1.25 to 6.99). In addition, injury status tended to be associated with both a warm-up duration ≥ 10 minutes (RR = 1.82; 95% CI 0.95 to 3.46) and carrying 20 or more discs when playing disc golf (RR = 1.85; 95% CI 0.96 to 3.54).
Table 4.
Exploratory analysis of potential risk factor
| Variable | n | Injured | RR | 95% CI | p value |
|---|---|---|---|---|---|
| Age (Years) | |||||
| 18 - 27 | 43 | 14 | 1 | ||
| 28 - 36 | 27 | 12 | 1.37 | [ 0.75; 2.49 ] | .31 |
| 37 - 68 | 35 | 15 | 1.32 | [ 0.74; 2.34 ] | .35 |
| BMI (Kg/m2) | |||||
| 20.2 - 23.5 | 36 | 12 | 1 | ||
| 23.6 - 26.9 | 35 | 15 | 1.29 | [ 0.71; 2.34 ] | .41 |
| 27.0 - 38.0 | 34 | 14 | 1.24 | [ 0.67; 2.28 ] | .50 |
| Disc golf experience (Years)† | |||||
| 0.5 - 1.5 | 26 | 9 | 1 | ||
| 1.6 - 4 | 38 | 16 | 1.22 | [ 0.64; 2.32 ] | .55 |
| 4.1 - 36 | 32 | 16 | 1.44 | [ 0.77; 2.72 ] | .24 |
| Score (+/− 0) | |||||
| −8 - 0 | 43 | 23 | 1 | ||
| 1 - 4 | 27 | 11 | 0.76 | [ 0.45; 1.30 ] | .32 |
| 5 - 28 | 35 | 7 | 0.37 | [ 0.18; 0.76 ] | .007* |
| Warmup (min) | |||||
| 0 - 2 | 35 | 9 | 1 | ||
| 3 - 9 | 25 | 11 | 1.71 | [ 0.84; 3.50 ] | .14 |
| 10 - 15 | 45 | 21 | 1.82 | [ 0.95; 3.46 ] | .07 |
| Discs (#) | |||||
| 1 - 11 | 35 | 9 | 1 | ||
| 12 - 19 | 30 | 13 | 1.69 | [ 0.84; 3.38 ] | .14 |
| 20 - 35 | 40 | 19 | 1.85 | [ 0.96; 3.54 ] | .06 |
| Tournaments (#) | |||||
| 0 - 2 | 41 | 8 | 1 | ||
| 3 - 12 | 29 | 14 | 2.47 | [ 1.20; 5.12 ] | .01* |
| 13 - 150 | 35 | 19 | 2.78 | [ 1.39; 5.56 ] | .004* |
| Group | |||||
| Amateur | 38 | 7 | 1 | ||
| Intermediate | 56 | 28 | 2.71 | [ 1.32; 5.57 ] | .006* |
| Professional | 11 | 6 | 2.96 | [ 1.25; 6.99 ] | .01* |
RR = risk ratio, Discs = number of discs carried while playing, Group = designation per Professional Disc Golf Association categories.
p < 0.05,
n = 96, as only categorical data was collected for < 6 month
DISCUSSION
The results of the present study indicate that 13.3% of the study population currently suffered from a disc-golf related injury, while 39% reported having sustained at least one injury during their disc-golf career. The majority of the current injuries affected the shoulder region, while the shoulder and elbow were the most affected anatomic regions of previous injuries. These results indicate that despite being a low-intensity non-contact sport, injuries in disc golf do occur.
This is the first study to report data on point prevalence and duration of injuries in the sport of disc golf. Nelson and colleagues reported a 81.8% all time prevalence of injury,5 which is in great contrast to the 39% all time prevalence of injury found in present study. This difference may partly be due to the conservative seven-day time-loss definition utilized in present study, as less severe injuries would not be included.12 As the present study recruited players both online and on disc golf courses, it is also possible, that the included players are less experienced and exposed to disc golf, than players being recruited directly from the PDGA website,5 an argument further supported because >50% of players reported six or more years of disc golf experience.5 Despite this discrepancy, the results of the present study indicate that the shoulder and elbow are the main regions of injury in disc golf players, supporting the findings of Nelson and colleagues.5
The actual Danish disc-golf population is unknown,3 and therefore the authors are unable to compare the current sample population with relation to the entire population. However, as an estimate of 500 disc-golf club members in Denmark has recently been suggested,18 the 71 club members in the current sample would represent 14% of the entire club-population in Denmark. In addition, as the registered Danish PDGA member-base consists of 158 members,1 a cross reference revealed that 50 of these PDGA members participated in the current study, which strengthens the representativeness of the sample. Finally only three females (3%) participated in the study which, despite being a proportion lower than the 7.1% females in the study of Nelson and colleagues,5 and the 8% member demographic in PDGA,2 illustrates a highly male-dominated sport.
The current data indicates that most injuries in disc golf occurs to the shoulder and elbow of the throwing arm (Table 2), supporting the initial assumption of a different injury pattern than ultimate frisbee.10 Injuries to these regions are common in sports with elements of overhead motion, such as badminton and the throwing events of athletics, and may be associated with the repetitive overhead motions, during which the shoulder are abducted and externally rotated.19 Interestingly, the data indicates that only 1% (IQR 5) of throws are overhead-throws, which suggests that other explanations of the injury pattern must be considered. It is possible, that these regions are particular susceptible to injury a result of the likely substantial biomechanical forces generated, when driving the ∼175gram discs distances up to 263 meters.20 The kinetic chain has been extensively investigated as a key mechanism to maximize force development in the large segments of the legs and trunk, and to transfer energy to the smaller, distal, segments of the shoulder, arm and hand.21-23 Assuming a similar mechanism is present in disc golf, the injury pattern observed in present study could be due to a suboptimal kinetic chain, forcing players to increase force generation in the relatively smaller segments of the shoulder and elbow, potentially leading to higher risk of injury in these segments.24 In addition, even though gradual onset injuries are poorly understood, they are presumably caused by cumulative micro-damage to the tissues, following a period of excessive loading of the tissues or insufficient recovery.25 As intermediate and professional players perform more throws and participate in greater number of hours per week of disc golf than amateurs (Table 1), such accumulation could potentially occur during the many repetitive forceful throws and ultimately lead to injury, even in players with highly developed kinetic chain functional strategies. Future biomechanical studies are warranted to elucidate the specific injury mechanisms.
Point prevalence measures may be influenced by seasonal variance,26 and one must note that the current study was conducted in the beginning of the Danish disc golf tournament season, during which more injuries are prone to occur.27,28 In fact, this tendency is likely to influence the results, as five (33.3%) of the current injuries observed in the present study, had a duration of a month or less (Table 3). Therefore, it is likely that point prevalence observed from studies conducted during the later season, may differ from the current findings. Despite the seemingly low point prevalence, these data show that 66.7% of the 15 current injuries affected the players for at least a month (Table 3), which in a recent consensus statement marked the point of a serious severity injury.29 The median duration of current injuries were 240 days (IQR 1410 days), further indicating that some injuries may adversely affect disc golf players for prolonged periods of time. The vast majority of these current injuries (93%) had a gradual onset (Table 3), and as the symptoms of gradual onset injuries may appear transient, players in other sports commonly continue to participate, despite their injury.30 All 14 players reporting being currently injured played at least 1 hour of disc golf per week during the last month (not reported), and therefore it is possible the continual participation may aggravate or prolong the injury duration.31,32
Ultimately, two notable observations deserves attention. First, only 43% of the disc-golf players received any means of technique-oriented guidance during their first year playing disc golf. Without proper initial technical guidance, new players may fail to properly develop the kinetic chain, forcing the player to generate more energy at the distal segments,22 or adapt potentially deleterious motor patterns, any of which may predispose the player to injury.33 Second, the disc-golf players warmed up for a median of five minutes (IQR 9), before playing disc golf. As the authors of a recent meta-analysis found that warm-up programs tended to reduce the risk of injuries,34 a structured warm-up routine may potentially be of benefit to disc-golf players.
The exploratory analysis indicated that reporting a low score, and therefore having a higher skill-level, was associated with a higher likelihood of reporting an injury. A high skill-level is a commonly identified risk factor in many sports,35,36 and could be partially explained by the high-skill players’ likely increased exposure to the sport,37 a tendency also observed in the present study (Table 1). As the high-skill players participated in more tournaments than players of lesser skill (Table 1), and as the number of tournaments played may be associated with higher risk of reporting an injury (Table 4), it is also possible the increased demands of tournament play may influence the risk of injury.38 The exploratory analysis also revealed a tendency of association (p = 0.07) between injury status and a warm-up duration of 10 or more minutes. This was unexpected as warm-up programs are assumed to reduce the risk of injury.34 As the retrospective design prevents assessment of temporal relationships, a potential explanation could be that players with previous or current injuries are more attentive towards warm-up procedures, not to risk recurrence of previous or aggravate current injury, than uninjured players. Another tendency (p = 0.06) of association was found when carrying 20 or more discs during rounds of disc golf (RR = 1.85; 95% CI 0.96 to 3.54). As carrying the golf bag is associated with a higher risk of injury in regular golf,39 the same pattern may exist in disc golf. Also, as disc-golf courses often includes obstacles and areas with inaccessible terrain,4,40 falls may be more frequent or severe when carrying a heavy bag. Though the explorative analysis indicates potential preliminary risk factors in disc golf, the authors stress that the present analysis identifies only association and not causation. These results are likely subject to confounding factors,41 as the statistical model used was crude, and thus the authors warrant caution during interpretation. To overcome the limitations of the present study, future research may benefit from using a prospective design, and a statistical analysis adjusted to potential confounding factors or taking into account the possibility for effect-measure modification or interaction.
A major limitation of the present study is the recall bias, inherent to the retrospective design. Gabbe et al.42 found that only 61% of football players could correctly recall their 12-month injury history, and as injury history was collected from the participants’ entire disc-golf career, a recall bias indisputably influences the results. To limit this bias, the study could have assessed only current injuries, as previous injuries might be more difficult to recall.43 However, had the authors focused solely on current injuries it is likely that the results would have failed to identify the elbow as a highly exposed injury region as seen in Table 2, and would have missed the plenty of acute injuries, as seen in Table 3. As such, the presentation of both previous and current injuries is performed, acknowledging that the data regarding previous injuries may be flawed. Another major limitation of the study is the small sample size, and the results must be gauged accordingly. More participants would have provided additional reliability to the findings, and would have allowed for a more comprehensive subsequent analysis. A further limitation of present study is the self-evaluation method used to collect data as it cannot be verified that players reported the truth, deliberately or not (i.e. if a participant forgets an injury), which might affect the validity of the present results. In addition, data was not collected on potential aggravating factors outside of disc golf, such as occupation or participation in other sports, which may also affect the validity of the present findings. Ultimately, a participation bias might be present, as even though the study was advertised on both disc golf courses and online, the retrospective design may fail to include players whom prior to this study withdrew from disc golf due to an injury, which could lead to an underestimation of the injury prevalence. It is also possible however, that players with no history of injury will choose to ignore the study invitation, or that previously injured players would be keener to participate, both of which would cause us to overestimate the injury prevalence.
Following the injury prevention model of van Mechelen et al.,44 future studies should attempt to identify causes of injury, including risk factors or injury mechanisms,44 preferably using prospective cohort studies.41 Studies may benefit from utilizing the injury recording method of Clarsen et al.,45 as most current injuries were gradual in onset and traditional methodologies of gradual onset injury registration may not be optimal.46 Ultimately, large-scale studies are warranted, as even though the present study was conducted nationwide, disc golf in Denmark is still a young and relatively unknown sport.
CONCLUSION
A 13.3% point prevalence of injury was reported with the greatest number of injuries occurring in the shoulder and elbow regions. The vast majority of injuries affecting the players were gradual in onset, and showed a median symptomatic duration of 240 days prior to the assessment.
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