Participation in physical activity has an important role in a healthy lifestyle. However, it is associated with an inherent risk of injury. A lateral ankle sprains (LAS) is the most prevalent lower extremity injury in sports and everyday life, posing a substantial healthcare burden and resulting in many long-term complications. Despite the attention and focus ankle sprains receive, it has been reported that up to 74% of individuals who experience an ankle sprain suffer from some type of residual symptoms, perceived instability (repeated episodes of “giving-way”), recurrent ankle sprains, and/or self-assessed disability, which may be termed as chronic ankle instability (CAI). The presence of CAI decreases activity levels, limits occupational involvements, and adversely impacts quality of life, as well as develops an early onset of degenerative pathology in the ankle, requiring costly medical diagnostic techniques and extensive treatments. Therefore, CAI is a significant public health concern in the physically active population and an economic burden of the global health care systems. With increasing government and societal emphasis on physical activity, the incidence of CAI would remain constant or increase as more individuals participate in physical activities. Researchers and clinicians must work together to minimize complications of CAI to maximize the potential health benefits of a physically active lifestyle.

Although ankle sprains receive abundant attention and focus in clinical practice and research, they persist as the most common injury that leads to recurrent injury in athletic activities. Understanding the cause of recurrent injury is crucial in implementing therapeutic interventions to ankle injury and reducing recurrent injury rate. Although excessive plantar flexion with inversion and external rotation in the ankle has been believed as the mechanism of an ankle sprain, it appears that the ankle sprain injury mechanism excessive rearfoot inversion and internal rotation coupled with ankle dorsiflexion. While various studies have shown that there are feed-forward and feedback alterations present in individuals with chronic ankle instability (CAI) as manifesting altered movement organization and muscle activation patterns during functional tasks, it is unclear whether these alterations are the result of the injury or initially contributed to it due to the lack of prospective studies. It is possible that compromised feedback responses, which may have been caused by the initial ankle sprain, contribute to the altered feed-forward control. Ankle instability appears to be linked to multiple aspects of insufficiencies. However, the potential synergistic relation between mechanical and sensorimotor impairments associated with CAI are unclear. It is important for future investigations to identify the source of alterations associated with CAI and identify exact factors that cause recurrent and secondary injury for developing more effective intervention and injury prediction model. Interventions that address multi-factorial aspects of impairments associated with CAI also are essential for improving both patient-oriented and clinician-oriented functional measures, decreasing disability, and preserving long-term healthy in individuals with CAI.

Lateral ankle sprain (LAS) is one of the most common injuries in competitive sports. This article organized the scientific evidence about the pathology, evaluation and treatment of LAS and chronic ankle instability (CAI). Athletes who injured LAS has various symptoms such as inflammation, restriction of joint range of motion, muscle strength deficit, decline balance control, fundamental movement abnormality which caused by various tissue damage. For LAS, it is important to properly evaluate these dysfunctions and advance treatment under the control of the athletic trainer, thereby preventing recurrent sprains and progression to CAI. In treatment for CAI, it is important to properly evaluate mechanical instability, functional instability, perceived instability, and functional performance and to organize individual disease states. Although treatments of CAI are verified by various methods such as balance exercise, joint mobilization, soft tissue mobilization, and resistance training, balance training is considered to be advantageous to prevent of recurrent sprains and improvement of activity of daily living. In future, it is necessary to develop appropriate treatment protocols according to severity and pathological condition.

Sports-related ankle sprains are extremely common among physically active population. An acute lateral ankle sprain typically causes pain, swelling, tenderness, and instability at the joint. The previous history of at least one ankle sprain has been identified as the strongest predictor of recurrent ankle sprains. It has been reported that the recurrent rate of ankle sprains exceeds 70%. Early injury management and proper follow-up care can help the healing process and reduce the risk of recurrent ankle sprains. In spite of these facts, many individuals who have suffered with ankle sprains do not seek medical treatment from a health care provider. Unfortunately, after the first ankle sprain, many individuals experience recurrent ankle sprains and suffer residual symptoms. Experiencing repetitive ankle sprains cause alteration in ankle joint mechanics and functions due to repeated disruptions in the structural integrity of the ankle, and it can lead to long-term consequences such as decreased health related quality of life and physical activity level throughout their lifetime. Furthermore, it has been reported that repetitive ankle sprains increase the risk of developing early onset post-traumatic osteoarthritis at the ankle. This evidence-based review explains overview of sports-related ankle sprain, residual symptoms associated with ankle sprains, and prevention of recurrent ankle sprains.

The purpose of this study was to investigate the influence of the difference of musculotendinous stiffness (MTS) on stretching induced effects. Twelve healthy male university students participated in this study. Maximum range of motion (ROM) at ankle dorsiflexion and MTS of ankle plantar flexors were measured in pre- and post- stretching. The plantar flexors were stretched for 2 minutes. Correlation between pre-MTS and maximum ROM increase was assessed. After stretching, maximum ROM had significantly increased (p<0.01). There was a significant decrease in MTS after stretching compared with before the stretching (p<0.01). A significant negative correlation was found between pre-MTS and maximum ROM increase（r=−0.69, p=0.011). The present study results demonstrated that a negative significant correlation between individual MTS and the stretching induced effects, which indicated that higher MTS might lead to smaller stretching induced effects such as flexibility.

It is often a problem that a lot of pitching is imposed on baseball players in high school age. In this research, we focused on the interval between consecutive pitching, and compared the impact on pitching performance by pitching tasks with different pitching interval. As a result, it was able to suppress to decreasing of the ball velocity significantly between first pitching and second pitching compared the 2 rest days to 1 or no rest day. On the other hand, in all three conditions, the average ball velocity in the second pitching was decreased significantly than one in the first pitching. Therefore, it was suggested that it is necessary to set a rest day at least 2 days after pitching to maintain pitching performance.

The aim of this study was to investigate the effect of taping and fatigue on ankle joint for the bounding performance and kinematics of lower extremity during bounding jump. Twelve collegiate athletes performed two-step bounding jump and the data during first step was analyzed. The distance of bounding jump, ground reaction time, the angle of lower extremity joints (ankle, knee, and hip joints), the motion of pelvis, ground force and EMG were measured. The obtained data were compared among control, ankle taping, and fatigue condition using ANOVA. As a result, decrease of jump distance and compensatory kinematics of lower extremity were observed both ankle taping and fatigue condition. These results suggest that the mobility of ankle joint should be maintained during jump performance.

The purpose of this study was to investigate the plantar pressure distribution during turn movements. Eighteen collegiate football players were instructed to run and turn with their right legs in 3 directions: side cutting, straight running, and crossover cutting. The medial side of the forefoot experienced significantly greater plantar pressure during side cutting task and the lateral side of the forefoot experienced significantly greater plantar pressure during crossover cutting task. The present study reveals that the plantar pressure increases load to the side of movement direction. In future studies, the relationship between plantar pressure and injury should be investigated.