It is widely accepted today that there are multiple physiological, psychological and behavioral benefits to participating in physical activity and sport in most populations. While the level of benefit varies across populations, there is inherent risk associated with participating in physical activity particularly in contact sports. Injuries, particularly to the ankle, have shown an increase in incidence in the last few decades and represent the most frequently injured body location for sports injuries presented to emergency departments in multiple countries.
The nature of injuries occurring at the ankle include sprains, fractures, dislocations, and ruptures. Sprains have been recorded at two million occurrences per year in the United States, where half (49.3%) are attributed to athletic activities. In sporting populations specifically, ankle sprains are responsible for 15% of all diagnosed injuries. This is the most common injury diagnosed (relative to location and type), in most sports, at different competitive levels, across many countries. Furthermore, a study in North American high school athletes investigating costs assessed by quality adjusted life years, discovered that across three years and 648 ankle injuries, of which sprains were most common, there was a mean comprehensive cost of $11,925 per injury. By way of international comparison, data from the Netherlands revealed that, although each ankle sprain was associated with €360 ($507) for direct and indirect cost, their 234,000 incidences per year equated to an estimated €84,240,000 annual expense.
The ankle complex is organised by two primary sub-joints, the distal tibiofibular which is a fibrous syndesmosis joint, and the talocrural, a uniaxial synovial hinge; each with multiple supporting ligaments. The most common mechanism of injury is ankle inversion and as a result the anterior talofibular ligament has shown to be the most frequently involved ligament in ankle sprains. However, due to the sophistication of this multi-joint complex, damage to a variety of structures can happen with differing associated diagnoses. A sprain injury is defined as structural damage to a ligament. Notably, the three types of ankle sprain are inversion or lateral ankle sprain (LAS), eversion or medial ankle sprain (MAS), and syndesmosis or high ankle sprain (HAS).
In addition to the established prevalence, studies investigating several sports have also shown that ligamentous injuries, compared to muscle and tendon (strains), may have the highest severity, that is days lost from participation in training or matches (time-loss) A recent study investigating injury burden in inline-hockey players representing ten teams and both sexes, found that among all severe injuries (≥29days lost) sprains of the ankle presented the highest prevalence (16%), with ankle fractures second most common (8%). Field-based sports also report high severities from ankle sprain. A recent investigation over three seasons reported 24.7 average days lost for ankle sprains in rugby union, where another study in soccer found an average loss of 33 days for lateral ankle sprains. Although many sport settings may lack the resources for regular radiological examination of each ankle injury, a report from the 2016 Summer Olympic Games in Rio de Janeiro showed that 10% of all MRIs (magnetic resonance images) performed were at the ankle, of which 45% revealed ligamentous injuries. In addition to time-loss, consequences include but are not limited to the direct and indirect costs of diagnosis, treatment and management, long-term physical complaints even after 5-years of onset (i.e. chronic ankle instability), and risk of recurrence.
There has long been a strong focus on injury prevention within the sports science community, first presented in 1992 by Van Mechelen et al. and their four step process, and an updated model by Finch in 2006. In injury epidemiology research and practice, a primary goal is to identify risk factors that may detect early deficits or abnormalities in movement and human performance, which may lead to an increased risk of sustaining injury. These risk factors may pertain to the athlete directly (intrinsic) or their environment (extrinsic). As described by Taimela et al., intrinsic factors (e.g. proprioception) are characteristics which stem from the individual themselves, and predispose oneself to an injury; whereas extrinsic risk factors (e.g. footwear) are independent of the individual but can be related to the onset of injury. Both intrinsic and extrinsic risk factors may be considered modifiable (e.g. strength) or non-modifiable (e.g. leg length). Extrinsic factors such as playing surface, weather, time zone and travel, have been previously investigated for both risk of injury and player performance.
Ankle sprains are often reported as the most common injury among athletes, therefore it is necessary for applied practitioners such as strength and conditioning coaches and physiotherapists to know what are the risk factors for ankle injury associated with their particular sport (i.e., field-based, team contact sport). While previous reviews have been conducted regarding ankle sprains, they tend to focus on treatment and management or risk of recurrence and long-term effect. For reviews which have identified associated risk factors, some address only one type of ankle sprain, and others require updating with more recent literature.
The aim of this systematic review was to identify prospectively measured ankle sprain risk factors in field-based team contact sports.
4012 records were returned from the online search and seventeen studies met the inclusion criteria for this review. Twelve different risk factors including anatomic alignment of the foot and ankle, joint laxity, height, mass, BMI (body mass index), age, ankle strength, hip strength, single leg landing performance (ground reaction force, pelvic internal rotation and knee varus), and single leg reach were all found to be associated with ankle sprain incidence. Injury definitions and methods of diagnosis and recording varied across the 17 studies.
This review has two overall findings, firstly from more than 20 categories of risk factors investigated for ankle sprain association across 17 studies in field-based team contact sports, 12 variables were found to be associated with increased incidence of ankle sprain in field-based team contact sport athletes. From the studies reviewed, no movement screen scores including from a modified-FMS nor Soccer Injury Movement Screen showed an increased risk of sustaining ankle sprain. In order to reduce the risk of ankle sprain, practical assessment of BMI, ankle plantar and dorsiflexion strength, hip strength, and single leg landing performance should be factored in to athlete assessment and subsequent program design. Ankle sprain interventions must be included in a whole-body program in order to maximize the transfer from research to pragmatically reducing injuries. In addition to these practitioner focused elements, considering that ankle sprains are the most prevalent injury across all sports, from this review it remains clear that more prospective studies with large sample sizes across both sexes, utilizing standardized definitions and methods of recording and reporting are needed. While etiological studies will identify risk factors, there will always be an inherent risk of injury in sport. Therefore, applied research will intend to reduce injury risk, occurrence or severity, rather than prevent.
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Dolan P., Kenny I.C., Glynn L.G., Campbell M.J., Warrington G.D., Cahalan R., Harrison A.J., Lyons M. and
Comyns T.M. (20xx). Risk Factors for Acute Ankle Sprains in Field-Based, Team Contact Sports: a Systematic
Review. The Physician and Sportsmedicine. IF 2.241, Q2, 55/116 [in press] DOI: http://dx.doi.org/10.1080/
Patrick Dolan is a US native, born and raised in Philadelphia. He comes to us from working for Red Bull New York after leading all performance operations for the Academy and assisting the First team (MLS). He most recently served as the Tournament Medical Coordinator for the World Lacrosse U21 Men’s World Championships. Additionally, he remains a Sports Science Network Professional for US Soccer, providing support in strength and conditioning and sport science to US Youth National Teams during domestic and international training camps and matches. He was the Head Strength & Conditioning Coach at Manhattan College, Assistant Director of Strength & Conditioning at Santa Clara University, and a Graduate Assistant Strength & Conditioning Coach at Lindenwood University. Patrick is an Approved Mentor for the Collegiate Strength and Conditioning Coaches Association (CSCCa), and began as a Certified Strength and Conditioning Specialist (CSCS) in 2012 with the National Strength and Conditioning Association (NSCA).