This article systematically reviewed the epidemiology studies on sports injury which ankle injury was included. The time span started from 1977 to 2005. A total of 227 studies reporting injury pattern in 70 sports from 38 countries were included. The total included cases were 201600 with 32509 (16%) ankle injuries. A total of 11847 (84%) ankle sprains were recorded from 14098 cases with available ankle injury information. Results show that the ankle was the most common injured body site in 24 of the 70 included sports, especially in aeroball, wall climbing, indoor volleyball, mountaineering, netball, and field events in track and field. Ankle sprain was the major ankle injury in 33 of the 43 sports, especially in Australian football, field hockey, handball, orienteering, scooter and squash. In general sports injury among countries, the ankle was the second most common injured body site after the knee, and ankle sprain was the most common type of ankle injury. The incidence of ankle injury and ankle sprain was high in court game and team sports, such as rugby, soccer, volleyball, handball, basketball, field hockey, dancing, American football, netball and lacrosse. This systematic review provides a summary of the ankle injury epidemiology in sports. 1. Introduction People from all around the world are participating in sports nowadays for personal interest, relaxation, health and fitness training. However, sports is one of the major causes of injuries which is comparable to traffic accidents, home and leisure accidents, occupational injuries, and violence [1-4]. Sports injuries result in pain, loss of playing or working time, as well as medical expenditure. Severe injuries may result in bone fractures, functional instability, limited mobility, disability, permanent cease of sports participation, psychological problem, and perhaps death. For world-class and commercial sports teams, absence of key players due to unexpected injuries may result in defeats in major games and huge economic loss. Due to these undesired adverse effects, scientists and medical specialists are actively working on sports injury prevention [5-7]. The aim is to prevent sports injury and let people enjoy sports participation. The first procedure to tackle a problem is to identify the problem. In 1970, Roser and Clawson conducted an epidemiology study on football injuries in young athlete [8]. In 1971, MacIntosh conducted similar study on athletic injuries in University of Toronto [9]. In 1972 and 1973, Garrick conducted related studies in prevention of sports injuries [5] and prevention of ankle sprains [10]. To be more specific in identifying the problem, Garrick pioneered a series of ankle sprains epidemiology studies from 1977 [11]. Subsequent studies by Garrick investigated ankle injuries in different sport events including aerobic dance [12] , children and adolescent skiing [13] , women gymnastics [14] , ballet [15] , and in all sports [16]. From 1980 afterwards, numerous epidemiology studies were conducted on different sports, population, g...

This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL) which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprain injury, prescribing orthosis decreases the risk while increased exercise intensity in soccer raises the risk. For intrinsic factors, a foot size with increased width, an increased ankle eversion to inversion strength, plantarflexion strength and ratio between dorsiflexion and plantarflexion strength, and limb dominance could increase the ankle sprain injury risk. Players with a previous sprain history, players wearing shoes with air cells, players who do not stretch before exercising, players with inferior single leg balance, and overweight players are 4.9, 4.3, 2.6, 2.4 and 3.9 times more likely to sustain an ankle sprain injury. The aetiology of most ankle sprain injuries is incorrect foot positioning at landing -a medially-deviated vertical ground reaction force causes an explosive supination or inversion moment at the subtalar joint in a short time (about 50 ms). Another aetiology is the delayed reaction time of the peroneal muscles at the lateral aspect of the ankle (60-90 ms). The failure supination or inversion torque is about 41-45 Nm to cause ligamentous rupture in simulated spraining tests on cadaver. A previous case report revealed that the ankle joint reached 48 degrees inversion and 10 degrees internal rotation during an accidental grade I ankle ligamentous sprain injury during a dynamic cutting trial in laboratory. Diagnosis techniques and grading systems vary, but the management of ankle ligamentous sprain injury is mainly conservative. Immobilization should not be used as it results in joint stiffness, muscle atrophy and loss of proprioception. Traditional Chinese medicine such as herbs, massage and acupuncture were well applied in China in managing sports injuries, and was reported to be effective in relieving pain, reducing swelling and edema, and restoring normal ankle function. Finally, the best practice of sports medicine would be to prevent the injury. Different previous approaches, including designing prophylactice devices, introducing functional interventions, as well as change of games rules were highlighted. This paper allows the readers to catch up with the previous researches on ankle sprain injury, and facilitate the future research idea on sport-related ankle sprain injury. Review IntroductionAnkle ligamentous sprain injury is the most common single type of acute sport trauma [1]. Over the years, various preventive strategies have been implemented, however, a recent epidemiology revealed that ankle sprain injury still dominated in sport injury, as it accounted for 14% of all attendance in an a...