Sport Injury Epidemiology
- 1 Introduction
- 2 Determinants of Sports Injury Incidence
- 3 Principles and Methods of Sport Injury Epidemiology
- 4 Incidence and Prevalence
- 5 Characteristics, Incidence and Nature of Injuries
- 6 Recording and Reporting of Epidemiological Data on Injury and Illness in Sport
- 7 References
Injury and illness epidemiology research in sport has grown over the last couple of years. Many international governing bodies of sport and the International Olympic Committee (IOC) have systems in place to conduct surveillance studies at various sporting events. Factors that influence this growing interest include injury and illness prevention and the long-term protection of athletes' health. Not only does an injury impact the health of an athlete but it also influences their ability to train as well as their performance. Furthermore, it influences their preparation for competition and their ability to take part in competitions. This in turn may have a significant effect on their lifetime dreams and goals of success as an athlete.
The overall risk of injury can be quantified through information about the incidence, severity and nature (location and type) of sports injuries. This in turn may provide information that can aid proper injury prevention initiatives. The goal of sports injury epidemiology is thus to provide information on various determinants of sports injury incidence in order to identify and implement injury prevention measurements.
Determinants of Sports Injury Incidence
- Is there a greater risk of injury in certain sports?
- What parts of the body are more likely to be injured?
- What type of injuries are most likely to occur?
- What sports are more dangerous?
- What sports often have more severe injuries?
- What factors influence the likelihood of an injury?
- Can injuries be prevented?
- Are injury prevention strategies effective?
When considering these determinants, sports injury epidemiology can be defined as: "The study of the distribution and determinants of sports injuries for the purpose of identifying and implementing measures to prevent their development."
Principles and Methods of Sport Injury Epidemiology
A basic understanding of study design and related terms are necessary to understand and interpret data sports injuries. The two basic types of study designs are:
- Descriptive studies - primarily used to understand the scope of the problem and identifying trends
- Analytical studies - to assess risk and identify risk factors
Usually, the research question to be answered drives the decision as to which study design to implement.
Types of Study Designs
The table below gives a good overview of the types of study designs (adapted from Applied Sports Injury Epidemiology)
|Case Series||to assess the scope of the problem||injured participants|
|Cross-sectional||determine prevalence of a problem in defined population||all participants or a sample of participants in a defined area|
|Case-control||evaluate risk factors among injured and non-injured participants||injured participants and controls (non-injured)|
|Case-crossover||to evaluate proximal risk factors among injured participants||injured participants|
|Prospective (cohort)||assess incidence of an injury
investigate cause and effect
|uninjured cohort with assessment of exposure|
|Randomised controlled trial||gold standard
assess incidence, risk factors and causality
assess prevention strategies
|uninjured cohort with assessment of exposure and random assignment to treatment groups/interventions|
Incidence and Prevalence
Two key concepts in sports injury epidemiology are incidence and prevalence.
Prevalence is defined as the proportion of currently injured athletes in a sports population. For example in a sports team prevalence is the number of players unable to play or practice as a result of injury on a particular day. Note that prevalence is defined at a specific moment in time.
Incidence measures the occurrence of new injuries in a population.
Characteristics, Incidence and Nature of Injuries
Various injury surveillance programs exist across a wide range of sports i.e. Olympics (the IOC Injury and Illness Surveillance System for Multi-sport events), FIFA World Cup Injury Surveillance System, Rugby World Cup Injury Surveillance System, IAAF Injury Surveillance System. As already emphasised these surveillance methods are crucial in the effective protection of the health of athletes. Epidemiological data is essential to contribute to better planning and provision of athlete health care. Furthermore, it is important in the development of injury and illness preventative measures. Some aspects included in injury surveillance systems are discussed below.
In longitudinal injury surveillance systems, injury incidences can be compared to earlier results and changes can be identified. These observed changes in injury incidence can be attributed to various factors such as:
- changes in competition rules
- change in competition program (i.e. new sports introduced at Olympics)
- changes in equipment
- changes in environmental factors
- change in venue or track design
- influenced by recording and reporting of injuries and illnesses by athletes and medical staff
- the result of natural variability of athletes' exposure to risk ( emphasising the importance of ongoing surveillance systems to monitor trends over time)
Severity, Location and Type of Injuries
In major sports events, even a minor injury or illness with or even without time loss can be consequential. Such injuries or illnesses have the potential to keep an athlete from participating or have an impact on the athlete's performance. This may prevent the athlete from fulfilling their potential and achieving the goal that they worked so hard for.
The risk of concussion is of great concern in certain sports and its diagnosis, prevention, management and return to play criteria have been studied and addressed in recent consensus statements.
Causes, Mechanisms and Onset of Injury
The causes, mechanisms and circumstances of injuries in training and competition may vary between different sports. Furthermore, acute injuries are often reported, whereas the reporting of overuse injuries with a gradual or sudden onset remains unclear due to limitations in the recording of overuse injuries.
Recording and Reporting of Epidemiological Data on Injury and Illness in Sport
The most recent consensus statement of the IOC: International Olympic Committee consensus statement: methods for recording and reporting of epidemiological data on injury and illness in sport 2020 (including STROBE Extension for Sport Injury and Illness Surveillance (STROBE-SIIS)) provides guidance to researchers on how to plan and conduct data collection and how to report this data. Some of the important factors discussed in this statement include:
- Defining and classifying health problems
- Terminology for health problems
- Health is "a state of complete physical, mental and social well-being" and not just the absence of disease
- An athletic health problem is defined as "any condition that reduces an athlete's normal state of full health, irrespective of its consequences on the athlete's sports participation or performance or whether the athlete sought medical attention.
- Medical attention health problem - a health problem that results in an athlete receiving medical attention
- Time-loss health problem - a health problem that results in an athlete being unable to complete the current or future training session or competition
- Terminology for health problems
- Defining injury and illness
- Injury is defined as "tissue damage or other derangement of normal physical function due to participation in sports, resulting from rapid or repetitive transfer of kinetic injury."
- Illness is defined as "a complaint or disorder experienced by an athlete, not related to injury." Illness includes physical, mental or social well-being health related problems.
- Relationship to sports activity
- Health problems may result:
- directly from participation in a competition or from training in the fundamental skills of a sport
- indirectly from participation in activities that are related to competition or training, but not during competition or training (eg. illness following international travel to a competition)
- activities not related to participation in sport (eg, car crash)
- Health problems may result:
- Mode of Onset
- sudden or gradual onset
- Classifying the mechanism of injury
- direct contact mechanisms
- indirect contact mechanisms
- non-contact mechanisms
- Severity of health problems
- described using various criteria, such as:
- duration of the period for which the athlete is unable to train/play ("time-loss")
- investigators should record severity as the number of days that the athlete is unavailable for training/competition
- recorded from the date of onset until the athlete is fully available again for training/competition
- the athlete's self-reported consequences (patient-rated measures of health and performance)
- Oslo Sports Trauma Research Center Questionnaire on Health-Problems (OSTRC-H) - useful too
- clinical extent of illness/injury
- clinicians may report the severity of health problems based on clinical outcomes such as:
- need for hospitalisation
- retirement from sport
- permanent disability The full consensus statement can be accessed here
- Engebretsen L, Soligard T, Steffen K, Alonso JM, Aubry M, Budgett R, Dvorak J, Jegathesan M, Meeuwisse WH, Mountjoy M, Palmer-Green D. Sports injuries and illnesses during the London Summer Olympic Games 2012. British journal of sports medicine. 2013 May 1;47(7):407-14.
- Soligard T, Steffen K, Palmer D, Alonso JM, Bahr R, Lopes AD, Dvorak J, Grant ME, Meeuwisse W, Mountjoy M, Costa LO. Sports injury and illness incidence in the Rio de Janeiro 2016 Olympic Summer Games: A prospective study of 11274 athletes from 207 countries. British Journal of Sports Medicine. 2017 Sep 1;51(17):1265-71.
- International Olympic Committee Injury and Illness Epidemiology Consensus Group, Bahr R, Clarsen B, Derman W, Dvorak J, Emery CA, Finch CF, Hägglund M, Junge A, Kemp S, Khan KM. International Olympic Committee Consensus Statement: Methods for Recording and Reporting of Epidemiological Data on Injury and Illness in Sports 2020 (Including the STROBE Extension for Sports Injury and Illness Surveillance (STROBE-SIIS)). Orthopaedic journal of sports medicine. 2020 Feb 14;8(2):2325967120902908.
- Magee DJ, Zachazewski JE, Quillen WS, Manske RC. Chapter 30. Applied Sports Injury Epidemiology , Athletic and Sport Issues in Musculoskeletal Rehabilitation. Elsevier Health Sciences; 2010 Oct 29.
- Medmastery. Incidence and Prevalence - Everything you need to know. Published on 29 July 2016. Available from https://www.youtube.com/watch?v=cTp_ONVVrh8. [last accessed 4 January 2020]