Self-Reported Outcome Measures of the Impact of Injury and Illness on Athlete Performance: A Systematic Review.

BACKGROUND: Self-reported outcome measures of athlete health, wellbeing and performance add information to that obtained from clinical measures. However valid, universally accepted outcome measures are required.
OBJECTIVE: To determine which athlete-reported outcome measures of performance have been used to measure the impact of injury and illness on performance in sport and assess evidence to support their validity.
METHODS: The authors searched Ovid MEDLINE, Ovid EMBASE, CINAHL Plus, SPORTDiscus with Full Text and Cochrane library to January 2016. Predefined inclusion and exclusion criteria were applied and papers included if an outcome measure of performance, assessed in relation to illness, injury or a related intervention, was reported by an elite, adult, able-bodied athlete. A checklist was used to assess eligible outcome measures for aspects of validity. Reporting of this study was guided by PRISMA guidelines for systematic reviews.
RESULTS: Twenty athlete-reported outcome measures in 21 papers were identified. Of these 20, only four cited validation. Of these four, three reported evidence to support validity in elite athlete groups as defined by the predetermined checklist. Fifteen patient-reported outcome measures were identified, of which four demonstrated validity in young athletic populations.
CONCLUSIONS: Most athlete-reported outcome measures of performance have been designed for individual studies with no reported assessment of validity. Despite some limitations, the Oslo Sports Trauma Centre overuse injury questionnaire demonstrates validity and potential utility to investigate the self-reported impact of pre-defined conditions on athletic performance across different sports.

Key Points

Background

Athlete-reported measures of health, wellbeing and performance can add meaningful information to that obtained from traditional physiological and biochemical performance measures [1, 2]. Research which includes the athlete’s perspective has contributed to a greater understanding of development and performance along with issues pertaining to athlete welfare and wellbeing [1, 3].

Validity and reliability are key characteristics of self-reported outcome measures [4] and questionnaires with evidence of validity and reliability in a general population or even a younger active population have been previously used in the sporting setting. However their length, narrow focus or lack of specificity to the athlete population has led to widespread use of study-specific questionnaires within sports medicine. While this reflects an attempt to reduce the burden on the athlete and increase the relevance, it may compromise validity and reliability [2, 5].

The scores obtained from these self-reported measures should allow valid inferences to be made including hypothesis-testing, therefore they should be assessed for validity in the particular population of interest. Evidence of validity accumulates over time from multiple studies [4, 5], therefore there is a need for consensus regarding the methods used to record and measure health-related incidents and their consequences for athletes [4-6]. Used together these values describe change that can be distinguished from measurement error and is important to athletes [6].

Athletes are different from the general population [7, 8]. They have higher levels of physical function, psychological function and perceived health. Physical activity is often their main employment, therefore the morbidity consequences of injury and illness tend to be high [9]. Athletes may not manifest symptoms during activities of daily living, and existing outcomes measures may not detect problems resulting from the demands of their training and competition [10], thus development of outcome measures that are specific to high performance sport could be important [9, 11–13].

The negative consequences of health problems include impairment, activity limitation and participation restrictions [11, 12]. Information regarding the prevalence and impact of health-related incidents is important to establish the burden of health problems and inform appropriate preventive and health promotion strategies [13-17]. However, athletes may not always seek medical care or present as patients, therefore patient-reported outcome measures (PROMs) may not be sufficient to capture all available information [9, 11, 18–21]. Additional barriers to the use of self-reported outcome measures include time to complete and lack of accessibility [2, 22].

Measures that are easy to understand, administer, score and interpret are more likely to be useful to all stakeholders in sport, including athletes, clinicians, researchers, support staff, funding bodies and policy makers [9]. We aimed to review the evidence to determine which athlete-reported outcomes have been used to evaluate the impact of health problems on performance in sport. A secondary objective was to evaluate eligible outcome measures for evidence of validity and potential for future research.

Methods

In order to address the first objective we conducted a systematic review to answer the focused question: “Which athlete-reported outcome measures of performance have been used to measure the impact of injury and illness on performance in sport?”

Studies were included if they met the following eligibility criteria: (1) participants were currently or had been competing at an elite level as able-bodied athletes; elite level was defined as competitive at Olympic, international, national or professional level [7], (2) any outcome measure of performance, assessed in relation to illness, injury or a related intervention, was reported by the athlete including functional and generic patient-reported outcome measures (PROMS), athlete diaries, interviews and patient satisfaction surveys; (3) the study was published in English. Studies were excluded from the review based on the following criteria: (1) participants were under the age of 16 years; (2) participants were competing at a recreational level; (3) the study was undertaken with a heterogeneous sample (e.g. elite and non-elite, able-bodied and disabled, under and over age 16 years) without reporting groups separately.

Search Methods for Identification of Studies

Electronic Searches

The databases of MEDLINE (Ovid version), EMBASE, CINAHL Plus, SPORTDiscus with Full Text, and Cochrane library were searched to 26 January 2016. A sensitive search strategy was devised initially in MEDLINE including the following search terms: self-report * athlete * patient reported outcome measure * and used in subsequent searches. An overview of the search strategy is available on request.

Searching Other Resources

The reference lists of included studies were checked for other papers that might be suitable for inclusion.

Data Extraction

Titles and abstracts were screened for eligibility by one of the authors (JG). The full text of all potentially eligible studies was assessed for inclusion by two authors in duplicate and independently (JG and RGS), resolving disagreements by discussion. Where resolution could not be achieved, a third author, experienced in conducting systematic reviews, arbitrated (IN). For included studies, data were extracted using a specially designed form (piloted before use) also in duplicate and independently by two reviewers. Where information in a paper was unclear, the corresponding author was contacted for clarification. Data extraction related to type of study, setting where the study took place, sport, population, injury or illness regardless of need for medical attention and details of the outcome measure.

Quality Assessment

In order to address our second objective, validity of development of outcome measures was assessed. Aspects of validity were evaluated using a pre-defined checklist based on the taxonomy and criteria proposed by Terwee et al. [23, 24] for evaluation of measurement properties of health status questionnaires.

Validity

There are many types of validity evidence [6] including face validity (the instrument actually measures the intended construct), content and construct validity. We considered evidence for content validity to include a clear description of the measurement aim, the target population, the concepts being measured and item selection. In addition the target population should have been involved in item selection. Evidence for internal consistency required factor analysis to be applied, with a Cronbach’s alpha value between 0.7 and 0.95. Ideally there should be at least 50 participants and minimal floor or ceiling effects [21].

Evidence for construct validity included reporting of values to show convergent validity (agreement in scores from other outcome measures which aim to assess similar constructs) and/or divergent validity (low correlation with scores from outcome measures which assess different constructs). Correlation coefficients such as the Spearman rho or Pearson r are most commonly reported in construct validation studies [6]. There should be at least 50 participants and at least 75% of the results should support a previously defined hypothesis [21].

Reproducibility (Agreement and Reliability)

The outcome measure scores should reflect changes where real change has occurred rather than changes due to measurement error. Evidence for agreement included at least 50 participants and the standard error of measurement (SEM) to be reported along with smallest detectable change (SDC) and minimal important change (MIC) or convincing arguments that agreement is acceptable. Evidence for reliability required at least 50 participants and an intra-class correlation coefficient (ICC) of at least 0.7 to be reported [21].

Responsiveness (Longitudinal Validity)

Evidence for the outcome measurement instrument to detect clinically important change over time included correlation with scores from other outcome measures of the same construct. Interpretability was assessed from evidence that a (change in) score was clinically meaningful along with means and standard deviations (SDs) of scores of reference populations and participant subgroups. In addition an MIC should be defined [21].

Data Synthesis and Reporting

In keeping with the aims of the review, findings from eligible studies were combined narratively using tables of evidence. The characteristics of the outcomes were used to synthesise results as well as validity outcomes. Reporting of the review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline [25].

Results

The adopted search strategies yielded 6536 results. After removal of duplicates and titles clearly not relevant to the research question, 1358 articles were further screened by title and abstract for consideration in full text screening. The full text of 159 articles was assessed against eligibility criteria and 21 articles were finally included [26-46]. Agreement on article inclusion was high (0.8). Reasons for exclusion of full text studies are given in Fig. 1.

Fig. 1

PRISMA flow chart

Characteristics of Included Studies

The studies represented a range of countries, with the USA being the most frequent. Seven categories of health problems including hip and groin, knee, shoulder, lower back, eyes, oral health, overuse injuries and illness were represented across 34 different sports (Table 1). Ten of the 20 outcome measures were used in evaluations of medical interventions [31, 32, 34, 36–38, 41, 43–45].

Table 1

Characteristics of the studies

	No. of references
Country
USA [31–33, 36, 41, 44, 46]	7
UK [34, 39, 40, 43]	4
Norway [27, 29, 30, 42]	4
Australia [28, 35]	2
Nigeria [26]	1
Switzerland [47]	1
Sweden [45]	1
Germany [37]	1
Sport
Soccer	8
Athletics	7
Volleyball, aquatic, baseball, American Football, lacrosse, basketball	4
Equestrian, cycling, handball, skiing, swimming, wrestling, hockey, tennis, ice hockey	3
Gymnastics, rugby, floor ball, archery, beach volleyball, shooting, taekwondo, weightlifting, table tennis	2
Cricket, boxing, fitness, golf, judo, water polo, badminton, fencing	1
Health problem
Hip/groin [34, 37, 41, 44, 45, 47]	6
Any injury/illness [27, 30, 35, 42]	4
Knee [28, 29, 36, 43]	4
Shoulder [29, 31–33]	4
Oral health [26, 39, 40]	3
Eye [46]	1
Lower back [29]	1

Characteristics of the Athlete-Reported Outcome Measures

Athlete-reported outcome measures of performance included return to play, time to return to training/competition, level of competition, perception of performance compared to pre-injury, participation limitation, reduction in volume of training and impact on performance. A summary of the athlete-reported outcomes identified by the search is presented in Table 2.

Table 2

Characteristics of the self-reported outcome measures

Athlete-reported outcome measure	Domains/no. of items	Question asked to measure impact on performance	Scale	Time to complete/setting	Population in which measure has been validated
Oral health surveillanceStudy-specific questionnaire [26]	DemographicsHealth behavioursHistory of oral health problemsImpact on performance (32 items)	Have you experienced a dental problem during competition?If yes did it affect your performance in the competition?	Yes or no	8 min at pilotSelf-administered during competition	None
Injury surveillanceStructured interviewOSTRC injury questionnaire [27]	History of training/playingPresence of injury	Did you participate fully in first team training and available for match selection each week?Were you selected for the match squad?	Yes or no	Professional administeredEnd of season	Based on questionnaire developed for use in other elite sport groups
Knee injury and repairQualitativePre-designed diary and 5 semi-structured in-depth interviews [28]	Confidence buildingAnticipationAnxietyPhysical preparationPsychological preparationSocial supportDealing with fears	Not fully described e.g. feelings returning to competition?How did you feel after your first game?Was the injury still a concern?Do you feel ready to return to competition?	None	5 separate interviews each lasting 30–45 minDuring rehabilitation	None
OSTRC overuse injury questionnaire [29]	History of injuryImpact on performance (4 items) × 3: shoulder, knee, lower back	Have you had any problems participating during past week?To what extent have you reduced your training volume over the past week?To what extent have problems reduced your performance during the past week?To what extent have you experienced pain related to your sport during the past week?	Q1: 4 categoriesFull participation no problemsFull participation but with problemsReduced participationUnable to participateQ 2, Q 3: 5 categoriesNoneMinorModerateMajorUnable to participateQ 4 (pain): 4 categoriesNoneMinorModerateSevere	Self-administered e-mailDuring training period	Elite athlete population
OSTRC questionnaire on health problems [30]	History of illness/injuryImpact on performance (4 items)	Have you had any problems participating during past week due to illness/injury/other health problem?To what extent have you reduced your training volume over the past week due to illness/injury/other health problem?To what extent have injury/illness/other problems reduced your performance during the past week?To what extent have you experienced symptoms/health complaints related to your sport during the past week?	As above	Self-administered e-mail, followed up by telephone for clarification if neededDuring training/pre competition	Based on OSTRC overuse injury questionnaire
Shoulder injury and repairStudy specific questionnaire [31]L’Insalata shoulder questionnaireASES	Returning to pre-injury level of athletics (1 item)	Level of return to play	3 categories:Return to pre-injury levelReturn in a limited capacityUnable to play at all	Professional/self-administered	NoneL’Insalata shoulder questionnaireASESValidity in the general population
Shoulder injury and repairStudy-specific questionnaire [32]	Playing statusPost-op complicationsImpact on performance (5 items)	Seasons played since surgeryTime needed to return to competitionCompetitive level of returnPitch velocity compared with pre-injury levelsPitch control compared with pre-injury levels	3 categories:Increase in pitch qualityNo change in pitch qualityDecrease in pitch quality	Telephone interview	None
Hip groin injury and repairStudy-specific questionnaire [34]	DemographicsHistory of complaintImpact on daily activitiesImpact on sportPerception of fitness (5 items)	Time to return to trainingTime to return to sport competitively	Time in weeks4 categories:Light training, full trainingCompetitionFully match fit	Self- administered and telephone interview	None
KJOC shoulder and elbow questionnaire [33]	Playing with painImpact on performanceRelationship with coach (10 items)	How difficult is it to get loose or warm prior to competition or practice?How much pain do you experience in your shoulder or elbow?How much fatigue do you experience?How unstable is your shoulder/elbow?How much have problems affected your relationship with coach/management?How much has your velocity or power suffered?What limitation do you have in endurance?How much has your control suffered?How much do you feel your arm affects your current level of competition?	10-point VAS score	Self-administeredAt beginning and end of playing season	Overhead throwing athletes
Illness surveillanceAthlete diary [35]	DemographicsTraining loadIllness behaviour	Did you train?Are you ill or injured?	3 categories to score impact on training:Score 1 minimal = normal trainingScore 2 moderate = modified trainingScore 3 severe = discontinued trainingYes or no	Self-administered	Based on questionnaire developed by Australian Institute for Sport
Hip groin injury and repairStudy-specific questionnaire [37]	Return to playPain (5 items)	Resumption of sport within 28 daysTime to resumption of sport (days)Full return to sport within 28 daysTime to full return to sport (days)	Time: in daysLevel of performance	Telephone interview	None
Knee injury and repairStudy-specific questionnaire [36]	Return to sport (3 items)	Self -reported time to return to sportSelf-assessment of level of performanceLevel of competitive sport achieved after college	Time in monthsPercentage of pre-injury level of performance	Telephone interview	None
Hip groin injury and repairStudy-specific questionnaire [38]SF-12HOSHSAS	Quality of performanceReturn to play (3 items)	Athlete perception of percentage of pre-injury levelTime to return to playLevel of play	Percentage of pre-injury performanceTime: months2 categories: major league, minor league	Self-administered	NoneSF-12HOSHSASValidity for use in general population
Oral health surveillanceStudy-specific questionnaire [39, 40]	Health behavioursHistory of oral problemsImpact on performance (3 items)	To what extent have you been “bothered” by your mouth, teeth or gums over the past 12 months?To what extent have your mouth, teeth or gums affected your quality of life over the past 12 months?To what extent have your mouth, teeth or gums affected your athletic training or performance over the past 12 months?	5 categories:Not at allA littleSomewhatA fair amountA great deal	Professional administeredDuring competitionDuring training	Derived from global questions Validity for use in the general population
Hip groin injury and repairStudy-specific questionnaire [41]MHHSHOSUCLAVAS for pain	Return to sportTime to return to sport Level of competitionPain (4 items)	Return to sportTime to return to sportLevel of competition	2 categories:Same levelNot at allTime in months3 categories:Varsity high schoolCollegeProfessional	Telephone interview	NoneMHHSHOSValidity for use in the general population
Injury surveillance [42]	Time lost from training/competition (3 items)	How many minutes of match play did you do last week?How many hours of training did you do last week?Have you had any illness/injury that has restricted you from full participation in one or more training sessions and/or matches last week?	Time in minutes and/or hoursYes or no	Self- administeredText message	Based on questionnaire developed for use in other elite sport groups
Knee injury and repairStudy-specific questionnaire [43]IKDCLysholm knee scaleVISA-P	Return to sport (2 items)	Time to return to playLevel of return to play	3 categories:Return to same levelReturn to lower levelNot competing	Professional/self-administered	NoneIKDC, Lysholm validity in general populationVISA-P validity in active populations
Hip/groin injury and repairStudy-specific questionnaire [44]MHHSPatient satisfaction	Return to play (2 items)	Time to return to skating drills Number of NHL games played	Time in monthsNumber of games	Self-administered	NoneMHHSValidity for use in general population
Hip/groin injury and repairStudy-specific questionnaire [45]iHOT-12HAGOSHSASEQ-5DVAS for hip function	Return to play (1 item)	Return or not to pre-injury sport	Yes or no	Self-administeredWeb-based	NoneiHOT and HAGOS have validity in athletic populationEQ-5D for general population
Eye injury surveillanceStudy-specific questionnaire [46]	Playing historyCircumstances of injuryMedical behaviour/interventionConsequences of injury (34 items)	How much playing time did you miss because of the injury?Do you have any continuing problems from your eye injury?	6 categories: 0, sat out some of game/practice1–3 days3–5 days5–7 days>7 daysYes or no	Self-administeredDuring competition	None

ASES American Shoulder and Elbow Surgeons Standardised Shoulder Assessment, SF-12 Short Form-12 quality-of-life questionnaire, HOS Hip Outcome Score, HSAS Hip Sports Activity scale, MHHS Modified Harris Hip score, UCLA University of California Los Angeles Activity Score, IKDC International Knee Documentation Committee subjective knee evaluation form, VISA-P Victorian Institute of Sport Patellar Tendonitis questionnaire, iHOT International Hip Outcome Tool (Short Form 12), HAGOS The Copenhagen Hip and Groin Outcome score, EQ-5D EuroQol Health Status Questionnaire

Evaluation of Athlete-Reported Outcome Measures Used in Health Surveillance

Nine different athlete-reported outcome measures were used in ten observational (epidemiological or surveillance) studies [26, 27, 29, 30, 33, 35, 39, 40, 42, 46]. However, most were designed for use in individual studies without reference to evidence of validity. Self-reported information was used in one qualitative investigation of rugby players’ experiences following anterior cruciate ligament injury and repair, conducted over a period of rehabilitation and return to competition [28]. Quality criteria based on a pre-defined checklist [23, 24] were applied to the four questionnaires where the study had included a reference to evidence of validity of the outcome measure (Table 3).

Table 3

Validity checklist applied to eligible outcome measures

Athlete-reported outcome	Content validity	Internal consistency	Construct validity	Reproducibility (agreement)	Reproducibility (reliability)	Responsiveness	Floor and ceiling effects	Interpretability
KJOC shoulder and elbow questionnaire [10, 33]	+Clear description of target aim. Target population and experts involved in item selection and development	+Factor analysisCronbach’s alpha0.861	+Correlates well with established PROMs for upper limb (DASH and DASH for performing arts);Pearson r 0.84 and 0.86 respectively	+Data presented and discussed regarding meaningful clinical change	+Test-retest data reported	+Differentiates between players with pain and without painChange in scores reported for different subgroups	+Maximum average scores reported	+Score of 100 indicates maximum function
OSTRC overuse injury questionnaire [29]	+Clear description of target aim. Target population and experts involved in item selection and development	+Factor analysis using a principle component analysis extraction methodCronbach’s alpha 0.91	+Correlates with time loss recorded by conventional measures	0	0	?Severity score can be plotted for each athlete	−>15% of respondents achieve highest or lowest scores	+Severity score can be calculated out of 100
OSTRC questionnaire on health problems [30]	?Developed from OSTRC overuse injury questionnaire	?Factor analysisCronbach’s alpha 0.96For non-injury cases 0.97	+Correlates with time loss recorded by conventional measures	0	0	?Severity score can be plotted for each athlete	−>15% of respondents achieve highest or lowest scores	+Severity score can be calculatedout of 100Subgroups of illness, overuse injury and acute injury reported
Impact of oral health problems [39, 40]	−Target group not involved in item selection	−No factor analysisCronbach’s alpha not calculated	+Tooth decay associated with self-reported impact on performance	0	0	0	0	0

KJOC Kerlan Jobe Orthopedic Clinic, OSTRC Oslo Sports Trauma Research Centre, PROMs patient-reported outcome measures, DASH Disabilities of the Arm, Shoulder and Hand, + positive rating, ? intermediate rating, − negative rating, 0 no information available

Athlete- Versus Patient-Reported Outcomes to Evaluate Medical Interventions

None of the athlete-reported outcomes of performance used in evaluation of medical interventions cited assessment of validity; seven were used in conjunction with PROMs, not all of which cited validity in a sporting population (Table 2). However, three of the functional PROMs—International Hip Outcome Tool (iHOT-12), Copenhagen Hip and Groin Outcome Score (HAGOS) and Victorian Institute of Sport Assessment-Patellar Tendinopathy (VISA-P)—identified by this review have evidence of validity in a younger active population [48-50]. The three generic PROMs used in the studies—Short Form (12) Health survey (SF-12), Short Form (36) Health Survey (SF-36) and EuroQol (EQ-5D) Health Questionnaire—have been reviewed by another author and found to have limited validity in a sport and recreation population [9]. The Hip Sports Activity Scale (HSAS) used to identify level of sporting activity (Table 4) has evidence of validity in young patients with hip disease [47].

Table 4

Potential utility as an athlete-reported outcome measure of performance

Athlete-reported outcome measure	No. of questions	Study population	Advantages	Disadvantages
KJOC shoulder and elbow questionnaire [33]	10	Professional baseball players (203)	Validity, reliability and responsiveness in elite sport population [10]	Functional measure, region-specificSpecific to overhead throwing athletes
OSTRC overuse injury questionnaire [29]	4 (for each specified region)	Elite athletes (313): cycling, floorball, handball, volleyball, cross-country skiing	Validity in elite sporting population, severity score to measure impactUseful across different athlete groups	Problem must be specified in advance
OSTRC questionnaire on health problems [30]	4	Olympic candidates (313): archery, athletics, beach volleyball, boxing, cycling, handball, kayak, rowing, sailing, shooting, swimming, taekwondo, weightlifting, wrestling	Validity in elite sport population. Useful across different athletes groups	Athlete will only record problems they feel relevant
iHOT-12 [45]	12	High level athletes (32): soccer, hockey, long distance running	Validity in younger active population [49]	Functional PROMRegion-specific
HAGOS [45]	37	High level athletes (32): soccer, hockey, long distance running	Validity in younger active population [50]Comprehensive	Functional PROMRegion-specificLengthy
VISA-P [43]	8	Professional athletes (28): volleyball, soccer, basketball	Validity in younger active population [48]	Functional PROMCondition-specific
HSAS [38, 41]	10	Professional athletes (22): ice hockey, soccer, table tennis, floorballHigh level athletes (32): soccer, hockey, long distance running	Validity in sport population [47]Useful to clarify level of sport performance	Self-reported measureRegion-specific
Oral health questionnaire [39, 40]	3	Olympic athletes (278)Professional footballers (187)	Suitable for use across different athlete groups	Validity in the general population only [51]Region-specific

KJOC Kerlan Jobe Orthopaedic Clinic, OSTRC Oslo Sports Trauma Research Centre, iHOT International Hip Assessment Tool Short Form 12, HAGOS Copenhagen Hip and Groin Outcome Score, VISA-P Victorian Institute of Sport Patellar tendonitis questionnaire, HSAS Hip Sports Activity Scale, PROM patient-reported outcome measure

Discussion

Our key finding is that most athlete-reported outcome measures of performance to assess the impact of illness and injury on performance in sport identified in this review were developed for use in individual studies. There can never be a single study which validates an outcome measure; however, evidence of validity and reliability of the inferences drawn from the data accumulates over time with use in multiple studies, thereby allowing meaningful comparison across studies. One oral health self-reported measure of impact on performance was used in Olympic athletes and professional footballers, but evidence of its validity has been assessed in a general population only. Functional PROMs such as i-HOT12, HAGOS and VISA-P, developed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidelines, demonstrate validity in young, active populations but not specifically in elite sport groups (Table 4). The HSAS self-reported measure of athletic capability has evidence of validity and reliability and could be a useful model for a tool to report the level of competition of athletes in research studies. Although rich in qualitative information, athlete interviews require a substantial time commitment from both the athlete and the researcher, as does the use of multiple PROMs. Consistent use of outcome measures with evidence of validity and reliability could help to quantify the burden of injury and illness and relative risk in athletes across different sporting activities. Researchers should aim to identify and use outcome measures with evidence of validity in the target group in which they are to be used. Three athlete-reported outcome measures of impact on performance demonstrate validity in a high performance athletic population—the OSTRC overuse injury questionnaire, the OSTRC questionnaire on health problems and the KJOC shoulder and elbow questionnaire; however, the KJOC questionnaire is specific to overhead throwing athletes. All are short and straightforward to complete and measure impact on performance in terms of athlete-reported pain/symptoms, participation, volume and quality of training/competition.

Strengths and Limitations of the Included Evidence

There are challenges to drawing robust conclusions from the included evidence. In general, the data regarding the outcome measures were drawn from their use in single studies, although one measure of the impact of oral health on performance was used in two separate studies. Few questionnaires reported development using a structured approach and involvement of the target population, limiting their validity.

Strengths and Limitations of the Review

Eligibility Criteria; Performance Level

In order to limit the review we made a decision to limit the participants in the studies to high performance, able-bodied athletes. This focus resulted in several studies being excluded because the studies included participants with disabilities, participants under the age of 16 years or recreational sports people who could not be separated out from the highest level athletes.

Performance Versus Functional Outcomes

Return to play is dependent on a number of factors, most of which are outside an athlete’s control. Included studies had to demonstrate that a self-reported outcome measure was used to evaluate the impact upon performance in elite athletes. This resulted in exclusion of studies which included heterogeneous samples and reported on the development of functional outcome measures using the COSMIN criteria, such as the Functional Assessment Scale for Acute Hamstring Injuries (FASH) [52] and Victorian Institute of Sport Assessment—Achilles Tendinopathy (VISA-A)

Risk of Bias and Quality Assurance

We attempted to minimise bias by developing the protocol a priori and employing duplicate full-text screening and data abstraction. However, initial eligibility assessment of titles and abstracts was carried out by one researcher (JG), which might have introduced bias in study selection.

Comparison with Other Reviews

This review supports the finding of related reviews. One systematic review of PROMs used to assess Achilles tendon rupture management [53] applied COSMIN criteria to 17 region-specific and condition-specific outcome measures; the authors found only four were presented in articles that referenced development and/or validation of that outcome measure and of these only one was developed using recognised methodology for outcome measure development. A systematic review of instruments used to assess outcomes of sport and active recreation injury [9] listed seven different health status and health-related quality-of-life measures, five different functional outcome measures and three physical activity measures; the authors stated that none have been specifically or region designed to measure injury outcomes in a general sport and active recreation population. One recent study of low back pain in international level rowers [54] recommended using the OSTRC overuse injury questionnaire, demonstrating its potential for use across all sports.

Conclusion

Within the limits of this review there is currently no universally accepted athlete-reported outcome measure of the impact of injury/illness on performance in sport. Most questionnaires were designed for individual studies and evidence to support their validity, reliability and responsiveness has not been reported. The KJOC shoulder and elbow questionnaire has evidence to support its validity, reliability and responsiveness but is specific to professional baseball players. Consistent use of self-reported outcome measures with evidence of validity, reliability and responsiveness would lead to more reliable and comparable evidence. Despite some limitations, as a potential tool to measure athlete-reported impact on performance across a variety of sports, the OSTRC questionnaire on overuse injuries forms a model that could be adapted to evaluate the impact of any pre-defined health problem on athletic performance. The addition of items related to impact on quality of life could add value in terms of understanding the negative consequences of injury and illness in sport.

Valid self-reported outcome measures can contribute to a greater understanding of the impact of illness and injury on athletic performance.

There is currently no universally accepted self-reported outcome measure of athlete performance.

The Oslo Sports Trauma Research Centre overuse injury questionnaire has potential for development for use across different sports.