Our study showed that the ankle sprain affected 71% of our sample. This percentage was lower to the study conducted by Karen G. Roos et al, in which the prevalence of ankle sprains in National Collegiate Athletic Association Sports was 95% . However, another study showed that ankle sprains represented 15% of injuries occurring in the field of sport . These differences between the results can be explained by methodological difference such as; sampling techniques or the characteristics of the different groups in different contexts or even to the negligence of athletes of the preventive measures of ankle sprains, hence its high frequency.
2. Ankle sprain
As for the location of ankle sprains, we noted that unilateral injury was more frequent (77.6%) compared to bilateral injury (22.4%). This can be explained by the fact that ankle sprains frequently affect the dominant member of the athlete. According to Ekstrand and Gillquist jan, the risk of ankle injuries increases in the dominant member .
The male population was more affected by ankle sprains (64.5%). Our results were comparable to those found in a study by Karen G. Roos et al. In fact, they demonstrated that the exposure to ankle sprains in men was higher than women . The low vulnerability of women can be explained by their flexibility and by the practise of less offensive and lower risks sports.
The percentage of ankle sprains in athletes also varied according to the type of sport practised; it decreases from Basketball (86.2%) to Handball (75%), then Football (70%), Running (65.2%), Tennis (61.5%) and finally Volleyball (33.3%). A study by Romain Terrier et al. reported results comparable . These results can be explained by the facts that Basketball contains a lot of movements of brutal reception of the foot during parachute jumps that can cause a bascule of the foot in inversion or eversion cause though ankle sprains.
Based on our findings, cadets were the most affected category with ankle sprains (47.6%) compared to seniors (33.3%) and juniors (18.7%). These results can be explained, on one hand by the fact that cadets do not yet master the technical gestures. On the other hand by the fact, that seniors have usually a training rhythm more intense than cadets and juniors which can increase the rate of exposure.
All the athletes with ankle sprains were competitors. This result was similar to the one observed in a study conducted by Yeung Mphil et al. who were interested in competitor athletes . Therefore, the high frequency of training hours and the intensive rhythm for competitors can generate a hyper- extensibility of the ankle ligaments and solicit them which can make the ankle more at risk of developing sprains compared to amateurs that usually practise sport for leisure and just to stay in shape.
3. Associated factors
Regarding anthropometric data; the results showed that no statistically significant difference was observed for age, gender, height and body mass index. However, weight was shown to be statistically significant with ankle sprain (p = 0.033). A study conducted by Bruce D et al. on 118 college athletes demonstrated that height and weight were not related to ankle sprains . These results can be explained by the fact that the majority of our athletes have normal body mass indexes. Thus, we cannot resume if there is an association between the ankle sprain and excess of weight.
Concerning sports data, our results demonstrated that ankle sprain was associated to the type of sport practiced (p = 0,038) and to the profile of the athlete (p = 0,006). Indeed, the characteristics of all type of sports included in this study, solicit the ankle and its different compositions. Hence, the occurrence of ankle sprains.
According to Bruce D, Beynnon et al., the type of foot and the type of the hindfoot are not associated to the incidence of ankle sprain . Likewise, Dahle et al. and Barrett et al.  reported no correlation between anatomic foot type (pronated, neutral, or supinated) and the incidence of ankle sprains. Our results support these findings.
Regarding unipodal static balance, the majority of the athletes affected with ankle sprains had an alteration of the unipodal balance compared to those not affected. This association was found statistically significant with p < 0.05. This fact can be explained by the alteration of the ligaments that stabilize the ankle joint which can be responsible for static disorders.
In our study, the ankle instability was associated to ankle sprains. Indeed, residual ligament laxity can result in the loss of the joint stability. Therefore, the athlete may feel insecure. According to Thomas Bauer, ankle instability is the main sequelae that patients complain about after ankle sprains .
Regarding muscular force, only the long fibular and the posterior tibial muscles were found statically significant. These results can be explained by the fact that the eversers are the lateral stabilizing muscles of the ankle. During a sudden reversal movement, the weakened ones will not stabilize the ankle and they will let it roll up. However, the athlete may previously have a weakness of the muscles which would leave the ankle unstable and can lead to the occurrence of ankle sprains.
The current study was conducted only in the region of Sousse. Hence the results cannot be generalized to the general population and also should be carefully interpreted.
In this study, we used a self-administrated questionnaire in order to assess ankle instability. However, questionnaires can be subjective and this can lead to an over or underestimation of the results.
Mmissing data on medical records of athletes were one of the most limitations that we have faced during the realization of this study. However, some medical questions were asked directly to the attending physician in order to fill the missing data.