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Abstract
Background This study describes the epidemiology of men's and women's tennis injuries reported by the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) during the 2009/2010–2014/2015 academic years.
Methods Injuries and athlete-exposure (AE) data originated from 19 varsity men's programmes (38 team-seasons); women's tennis data originated from 25 varsity programmes (52 team-seasons). Injury rates, injury rate ratios (IRRs) and injury proportions ratios (IPRs) were reported with 95% CIs.
Results The ISP captured 181 and 227 injuries for men's and women's tennis, respectively, for injury rates of 4.89 and 4.88/1000 AE for men and women, respectively. There were 32.2% and 63.9% reductions in men's and women's tennis practice injury rates between 2009/2010–2011/2012 and 2012/2013–2014/2015, but no reductions in competition injury rates. Competition injury rates were higher than practice injury rates in men's (IRR=2.32; 95% CI 1.72 to 3.13) and women's tennis (IRR=1.77; 95% CI 1.35 to 2.33). Most injuries in men's and women's tennis occurred to the lower extremities (47.0% and 52.4%, respectively), compared with the trunk (16.6% and 17.6%, respectively) and upper extremities (23.8 and 23.8, respectively).
Conclusions Injury rates in NCAA men's and women's tennis were similar overall. Practice injury rates in men's and women's tennis have declined, although competition rates have not changed. These findings may help inform injury prevention programmes in the future.
- Tennis
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Introduction
Tennis is a popular sport in the USA, with almost 18 million active participants and a ‘latent demand’ of almost 15 million people.1 In North America, most promising young players, such as Arthur Ashe, John McEnroe, James Blake and John Isner, developed their game in college before turning professional. Participation in women's collegiate tennis increased by almost 2500 athletes between 1981/1982 and 2013/2014, while men's tennis participation increased by about 700 athletes over the same time period.2 The official National Collegiate Athletic Association (NCAA) tennis season runs from January to May, and consists of team-based competitions. However, NCAA tennis athletes are active beyond the team season, as individual singles and doubles tournaments typically run from October to December each year.
Previous investigations regarding the incidence of tennis injuries and associated risk factors have mostly focused on youth and junior-level tennis players,3–8 or elite professionals.9 These publications, alongside thorough reviews of injury occurrence, aetiology and prevention,10 ,11 reported variations in incidences of tennis injuries, although most injuries occurred to the lower extremities. Attempting to draw clinical conclusions for specific populations such as collegiate tennis student-athletes may be difficult with these data.
The purpose of our study was to describe the epidemiology of NCAA men's and women's tennis injuries during the 2009/2010–2014/2015 seasons using data from the NCAA Injury Surveillance Program (ISP). This injury tracking system uses standardised definitions to track student-athletes at multiple NCAA-affiliated institutions.12 All injuries reported to the teams’ athletic trainers (ATs) are recorded in this database, allowing for an in-depth analysis of all reported NCAA tennis injuries, regardless of severity.
Methods
Data from the 2009/2010–2014/1015 academic years were obtained from the NCAA ISP. The ISP is a prospective surveillance programme managed by the Datalys Center for Sports Injury Research and Prevention, an independent, non-profit research organisation. This study was approved by the (name removed for blind review), with student-athletes from participating teams providing consent at the beginning of each academic year. Men's tennis data originated from 19 varsity programmes that contributed 38 team-seasons. Women's tennis data originated from 25 varsity programmes that contributed 52 team-seasons.
The methodology of the NCAA ISP during the 2009/2010–2014/2015 academic years has been previously described.12 Briefly, the ISP used a convenience sample of NCAA varsity sport teams representing all NCAA divisions across the USA. ATs reported injury data while working with the participating teams and attending school-sanctioned practices and competitions. The ATs reported injuries in real time through the electronic health record application used by team medical staff. In addition to musculoskeletal injuries, the surveillance system captured other sports-related adverse health events not reported in this investigation, such as illness, heat-related conditions and general medical conditions. Only varsity-level practice and competition events, and team conditioning sessions were included in the ISP data sets. Individual weight lifting and conditioning sessions were excluded.
ATs completed detailed event reports on the injury or condition (eg, site, diagnosis) and the circumstances of every event (eg, activity, mechanism, event type (ie, competition or practice)). ATs were able to review and update previously submitted information as needed during the course of a season. ATs also provided the number of student-athletes participating in each practice and competition.
From the electronic health record application, common data elements, including injury and exposure information, were stripped of identifiers and personally identifiable information.12 The frequency of export or submission of data varied slightly among vendors providing the electronic health record applications to team medical staff. This common data element standard allowed ATs to document injuries as they normally would as part of their daily clinical practice.
Electronic health record applications must have successfully completed a data-validation process to be certified. Exported data passed through an automated verification process that conducted a series of consistency checks. Data were reviewed and flagged for invalid values. The AT and data quality assurance staff were notified and worked together to resolve the issue. Data that passed the verification process were then placed into the men's and women's tennis aggregate data sets.
A reportable injury in the ISP was defined as an injury that: occurred as a result of participation in an organised intercollegiate practice/competition and required attention from an AT or physician. Multiple injuries occurring from one injury event could be included.
A reportable athlete-exposure (AE) was defined as one student-athlete participating in one NCAA-sanctioned practice or competition in which he or she was exposed to the possibility of athletic injury, regardless of the time associated with that participation. Only athletes with actual playing time in a competition were included in competition exposures. Diagnoses of specific injuries were based on the expertise of ATs.
Body parts were categorised as: head/face, neck, shoulder/clavicle, arm/elbow, hand/wrist, trunk (including chest, abdomen, upper back and lower back), hip/groin, thigh/upper leg, knee, lower leg (including the Achilles), ankle, foot and other. Injuries were also categorised by the number of days in which athletes were restricted from participation. Non-time-loss injuries were those injuries that resulted in restriction of participation <24 h. Within time-loss injuries, resulting in time loss of at least 24 h, we were particularly interested in severe injuries, defined as injuries that resulted in time loss over 3 weeks.13 Severe injuries may have also resulted in the student-athletes prematurely ending their season (ie, season-ending injury).
Data were analysed using SAS-Enterprise Guide software (V.4.3; SAS Institute, Cary, North Carolina, USA) to assess rates and patterns of college men's and women's tennis injuries. Statistical analyses included calculation of injury rate ratios (IRRs), injury proportion ratios (IPRs) and χ2 tests (χ2). The overall injury rate was calculated as the ratio of injuries per 1000 AEs. Injury rates were also calculated as the ratio of practice injuries per 1000 practice exposures, and the ratio of competition injuries per 1000 competition exposures. The following is an example of an IRR comparing competition and practice injury rates:
The following is an example of an IPR comparing the proportion of severe injuries sustained in male and female tennis players:
All 95% CIs not containing 1.00 were considered statistically significant. Because of statistical power concerns in time trends, we grouped the years as 2009/2010–2011/2012 and 2012/2013–2014/2015. Also, due to the small number of injuries, the majority of analyses use the overall count of injuries, as opposed to stratifying by competition and practice.
Results
Overall frequencies and rates
Men's tennis
The ATs reported 181 injuries during 2009/2010–2014/2015 in college men's tennis, of which 112 (61.9%) and 69 (38.1%) occurred during practices and competitions, respectively (table 1). Most injuries occurred in the regular season (77.9%); 19.3% and 2.8% occurred in the preseason and postseason, respectively. Three injuries (1.7%) required surgery; 54.7% were non-time loss and 11.0% were severe. Most of these severe injuries were to the trunk (20.0%) or ankle (20.0%), and were diagnosed as strains (25.0%).
Injury rates by type of AE in NCAA men's and women's tennis*, 2009/2010–2014/2015
These 181 injuries occurred during 36 994 AEs, for an injury rate of 4.89/1000 AEs (95% CI 4.18 to 5.61; table 1). The competition injury rate (8.88/1000 AE) was higher than the practice injury rate (3.83/1000 AE; IRR=2.32; 95% CI 1.72 to 3.13). The preseason injury rate (4.58/1000 AE) did not differ from the regular season injury rate (5.22/1000 AE; IRR=0.88; 95% CI 0.61 to 1.27).
Women's tennis
The ATs reported 227 injuries during 2009/2010–2014/2015 in college women's tennis, of which 149 (65.6%) and 78 (34.4%) occurred during practices and competitions, respectively (table 1). Most injuries occurred in the regular season (64.8%); 33.0% and 2.2% occurred in the preseason and postseason, respectively. One injury (0.4%) required surgery; 58.6% were non-time loss, and 5.7% were severe. Most of these severe injuries were to the foot (30.8%), and were diagnosed as fractures (23.1%).
These 227 injuries occurred during 46 530 AEs, for an injury rate of 4.88/1000 AEs (95% CI 4.24 to 5.51; table 1). The competition injury rate (7.36/1000 AE) was higher than the practice injury rate (4.15/1000 AE; IRR=1.77; 95% CI 1.35 to 2.33). The preseason injury rate (6.72/1000 AE) was higher than the regular season injury rate (4.47/1000 AE; IRR=1.51; 95% CI 1.14 to 1.99).
Comparison of rates and frequencies
There were no sex differences in men's and women's tennis injury rates overall (males vs females IRR=1.00; 95% CI 0.82 to 1.22) or for competitions (IRR=1.21; 95% CI 0.87 to 1.67). The women's tennis practice injury rate was 1.27 times that of men's tennis (IRR=1.27; 95% CI 1.02 to 1.60). The proportion of severe injuries in men's tennis was nearly double that of women's tennis, but this difference was not statistically significant (IPR=1.93; 95% CI 0.99 to 3.77).
Time trends
In men's and women's tennis, there were statistically significant decreases in practice or competition injury rates between the two time periods (2009/2010–2011/2012 and 2012/2013–2014/2015) (figure 1). There was a 32.2% reduction in the men's tennis practice injury rate from 2009/2010–2011/2012 to 2012/2013–2014/2015 (IRR=0.49; 95% CI 0.47 to 0.98), and a 63.9% reduction in the women's tennis practice injury rate (IRR=0.36; 95% CI 0.26 to 0.50). These decreases were not statistically significant in competition injury rates (men: IRR=0.90; 95% CI 0.55 to 1.45; women: IRR=0.69; 95% CI 0.44 to 1.07).
Injury rates per 1000 athlete-exposures (AEs) by academic year and event type, men's and women's tennis, 2009/2010–2014/2015.
Body sites injured and diagnoses
Most injuries occurred to the lower extremities in both sports (men: 47.0%; women: 52.4%; table 2). In both men's and women's tennis, large proportions of injuries were also sustained to the trunk (16.6% and 17.6%, respectively) and the shoulder/clavicle (14.4% and 11.9%, respectively). There were no sex differences in body part-specific injury rates.
Number of injuries and injury rates and time loss by body part in NCAA men's and women's tennis*, 2009/2010–2014/2015
The majority of injuries reported in both sports were diagnosed as: strains (men: 30.9%; women: 29.1%), sprains (men: 14.4%; women: 15.0%), inflammation (men: 10.5%; women: 10.1%) and tendonitis (men: 6.1%; women: 7.9%; table 3). There were no sex differences in diagnosis-specific injury rates.
Number of injuries and injury rates, and time loss by diagnosis in NCAA men's and women's tennis*, 2009/2010–2014/2015
Both men's and women's tennis reported similar specific injuries. The most prevalent were lateral ankle ligament complex sprains (men: 7.7%; women: 9.7%). In men's tennis, other prevalent injuries included: rotator cuff strains (3.3%) and wrist sprains (3.3%). In women's tennis, the other most prevalent injury was a quadriceps strain (3.5%).
Mechanism of injury
The majority of injuries reported in both sports were attributable to non-contact (men: 36.5%; women: 33.9%) and overuse (men: 36.5%; women: 43.6%; table 4). There were no sex differences in injury mechanism injury rates.
Number of injuries and injury rates and time loss by injury mechanism in NCAA men's and women's tennis*, 2009/2010–2014/2015
Discussion
Our results are the first to describe tennis injuries during men's and women's NCAA practices and competitions. The inclusion of non-time-loss injuries better illustrates the range of injuries diagnosed and managed by ATs. These findings will be beneficial to team medical staff working with NCAA tennis athletes when designing injury prevention programmes.
Definitions
In 2009, a group of international tennis experts produced a consensus statement on epidemiological studies of medical conditions in tennis.14 This consensus statement was intended to standardise data collection and reporting methods in order to better understand the true epidemiology of tennis injuries. The authors described a medical condition as ‘any physical or psychological symptom or manifestation sustained by a player that results from a tennis match or tennis training, irrespective of the need for medical attention or time loss from tennis activities.’ An important distinction to note in our study is that we only considered medical conditions to be musculoskeletal injuries that were reported to team medical personnel, although we did consider both time loss and non-time loss injuries in our results. In respect to the above definition, our findings should be interpreted as conservative estimates of true injury rates as we could not reliably collect information about injuries that were not reported to team medical personnel. It should be noted that we categorised body sites and AE as defined in the consensus statement. The 2009 consensus statement defines AE as player hours.14 The NCAA ISP does not collect information about player hours, but rather records whether or not each athlete participated in a given session (competition or practice). Thus, the definition of AE in our study differs slightly from the recommended definition provided in the 2009 consensus statement.14
Comparison with previous findings
Similar to other research regarding injuries among collegiate student-athletes,15 our findings suggest that injury rates were higher in competitions than in practices. Activities in practices may be less intense than those in competitions. Because practices are controlled environments, coaching staff may be better able to mitigate injury risk. For example, coaches might limit overhead activities following a weekend of competition in order to avoid overuse-type injuries, or to stress proper technique over power during serves. Nevertheless, the majority of injuries occurred during practices. Future sports injury research should determine manners in which practice activities can be modified to decrease injury incidence.
Comparing our findings with previous studies is difficult due to differences in methodologies. Hjelm et al3 ,4 reported injury rates per 1000 h of tennis, whereas our injury rates were reported per 1000 AEs. Overuse injuries comprised large proportions of injuries in all the studies, although the proportion previously reported3 was slightly higher (54% vs 37% in men's tennis and 44% in women's tennis). The main contributor to these differences is likely due to age of the participants, where previously, individuals aged 12–18 years were required to participate in tennis twice a week.3 Although each institution varies to a certain degree, NCAA athletes typically practice or compete 6 days/week for approximately 2 h each session. While it may seem intuitive that athletes who play more experience more overuse injuries, this is not necessarily the case. It is likely our participants benefited from stricter training regimens and higher fitness levels, potentially contributing to a lower overall percentage of overuse injuries.16 Gaw et al17 examined tennis injuries reporting to US emergency departments (ED). Although the proportion of injuries that were sprains/strains in their study was similar to our findings (44% vs 45% in men's tennis and 44% in women's tennis), the authors report a larger proportion of fractures (15% vs 3% in men's tennis and 2% in women's tennis).17 This illustrates the difference in injuries treated by ATs and EDs. Previous research has described the variation between basketball injuries that present to the ED and the athletic training room.18 In general, patients with less severe injuries that can be treated quickly and are more easily diagnosed (ie, sprains, strains, etc), are more likely to report to an AT, whereas injuries requiring more extensive diagnostic and treatment options often present to the ED. This underscores an important aspect to care provided by ATs, as avoiding costly and time consuming visits to EDs in cases of less severe injury may be beneficial to patients.
Despite varying methodology, our findings of greater lower extremities injury rates as compared with the trunk and upper extremities are similar to previous investigations.9 ,10 ,19 These consistent findings are important to clinicians and coaches working with tennis players. There are likely several factors contributing to higher rates of lower extremity injuries, including constant acceleration/deceleration, varying court surfaces, and potential high-load frontal plane movements. These potential contributors to lower extremity injuries must be considered in future prospective research. Understanding injury mechanisms will be key to developing appropriate and effective injury prevention and rehabilitation programmes.
Previous epidemiological reports have described injuries in various NCAA sports. Commonly, student-athletes in these sports suffer the majority of injuries to a particular extremity. Approximately 70% of all men's20 and women's21 soccer injuries are to the lower extremities. Sports such as gymnastics,22 volleyball23 and men's24 and women's25 basketball report the majority of injuries occur to the lower extremities. While our data show higher injury rates to the lower extremities, male and female tennis athletes appear to sustain a good portion of injuries to the upper extremities and trunk as well. Clinicians should consider more comprehensive strength and conditioning and injury prevention programmes for tennis athletes in order to reduce injury rates across the entire body.
Time trends and severe injuries
We found differences related to time and severity that warrant further examination. We observed a reduction in practice injury rates in men's (32.2%) and women's (63.9%) tennis from 2009/2010–2011/2012 to 2012/2013–2014/2015. We acknowledge these analyses were conducted over small timeframes, but the significant reduction in tennis practice injury rates is a positive finding. Although we can only speculate, it is possible that advanced training methods and improved monitoring have had a positive effect on tennis injury rates. Our data indicate considerably more AEs during practice than competition. Therefore, limiting injuries during practice should be a focus of clinicians and coaches. Continued prospective analyses will be helpful in determining if our reported decreases remain constant over time.
The proportion of severe injuries sustained by men appears to be larger than that of women. Approximately 1 in 9 injuries in men's tennis were severe, although the overall reported count of injuries in this study was small. Nevertheless, this is an alarming finding, particularly given the non-contact nature of tennis. Because the relatively low number of severe injuries in our sample of tennis programmes (men, n=20; women, n=13), we lacked the ability to further explore such sex differences. Future research should aim to elucidate the mechanisms behind these severe injuries in an effort to limit their occurrence.
Limitations
We were limited to data recorded by ATs working with each team. Previous work has shown the NCAA ISP to be a valid system capable of capturing the majority of injuries occurring throughout a given season.26 Our analyses were limited in that we could not investigate injury differences between different serve types, or injury rates between singles and doubles matches. We believe these investigations will be useful in the future to further understand the epidemiology of NCAA tennis injuries. We were unable to explore the affects of playing surface on injury rates due to limitations in the ISP data collection system. The ISP also does not capture injuries that occur outside of school-sanctioned practices and competitions. The data collection methods employed by the ISP do not allow for exposure rates to be calculated by time or event. This helps to reduce the burden on the ATs who are responsible for reporting injury events, and allows for comparisons between previous and future publications that employ the same methodology. Our results may not be generalisable to athletes competing in other NCAA programmes or levels of competition, or to other tennis athletes competing outside of the NCAA. Despite this, we feel our sample of NCAA athletes competing at a high level does allow for some generalisation to other athletes competing at similar levels of competition over similar playing periods.
Conclusions
Our study is the first to summarise tennis injuries sustained by male and female NCAA athletes. Important findings, such as higher injury rates in competition as compared with practice, may help inform future changes aimed at limiting NCAA tennis injuries. Our finding that about 1 of 9 injuries suffered by men's tennis players can be categorised as severe is alarming, especially given the non-contact nature of tennis. Finally, the reduction in men's and women's tennis practice injury rates over time is promising, although future work is needed to determine if this reduction remains over a longer period of time.
What are the findings?
We found that tennis players in our sample suffered more injuries to the lower extremities as compared with the trunk and upper extremities.
Men's tennis players suffered about twice as many severe injuries as women's tennis players, and approximately 1 of 9 injuries suffered by men's tennis players was considered severe.
There was a significant reduction in practice injury rates over time for men's and women's tennis, but no changes were noted in competition injury rates.
How might it impact on clinical practice in the future?
Reporting both time loss and non-time loss injuries better summarises medical conditions afflicting tennis athletes, and more completely addresses the burden of injury managed by the team medical staff.
Although tennis has not traditionally been associated with high rates of severe time loss injuries, our report indicates clinicians should be prepared to assess and manage severe time loss injuries in tennis athletes.
Acknowledgments
The NCAA Injury Surveillance Program data were provided by the Datalys Center for Sports Injury Research and Prevention. The authors thank the many ATs who have volunteered their time and efforts to submit data to the NCAA Injury Surveillance Program. Their efforts are greatly appreciated and have had a tremendously positive effect on the safety of collegiate athletes.
References
Footnotes
Funding National Collegiate Athletic Association.
Competing interests None declared.
Ethics approval National Collegiate Athletic Association.
Provenance and peer review Not commissioned; externally peer reviewed.