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Background and aim: Chronic ankle instability (CAI) is a current disability that can affect on activity daily living of the patients. Many studies have indicated postural control deficits in these patients but the effect of a dual task on postural control has not been examined yet.

Materials and methods: Postural stability in CAI patients and healthy subjects was measured using the Force Plate. Eight positions concluded two different stances (double & single) with closed or opened eyes. All positions concurrently were done with a cognitive task. Anterior/posterior (Rfa) and medial/lateral (Rsw) mean sway quantified static postural stability.

Results: Mean sway significantly increased in patients in the anterior/posterior (single and double leg stance) and medial/lateral (single leg stance) directions (P<0.05). While performing a dual task anterior/posterior mean sway decreases within the patients group on the impaired leg stance (P<0.05). No difference is seen in the healthy subjects.

Conclusion: Postural control deficits were identified in participants with chronic ankle instability. In view of the fact that a cognitive task resulted in decreasing displacement of center of pressure in patients, this method may identify as an examination and a plan of treatment for affecting on ankle stabilizing factors.

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Background and Aim: The rapid growth of the athletic training profession has been accompanied by an equally rapid increase in focus on basic and clinical research. Lateral ankle sprain (LAS) is an extremely common athletic injury. Despite extensive clinical and basic science research, the recurrence rate remains high. Chronic ankle instability (CAI) following LAS is hypothesized to predispose individuals to re-injury because of neuromuscular control deficits which result following injury. No investigation has been carried out on the existence of joint position deficits in the knee joint of patients with CAI. In this study, joint position sense (JPS) was evaluated in patients with CAI.

Materials and Methods: Ten female patients with CAI and ten healthy control subjects participated in this study. JPS was evaluated by reproduction of the angles in two standing and sitting positions, and in each position two target angles were tested. The knee joints in both lower limbs of patients and the dominant knee-limb of healthy subjects were evaluated. The knee angles were measured by using a system comprised of skin markers, digital photography, and Auto CAD software. Absolute error was considered as a dependant variable.

Result: There were no significant differences between the knee JPS of dominant leg in healthy subjects and both knee joints of patients. There were also no significant differences between knee JPS in two standing and sitting positions and in two different target angles (p>0/05).

Conclusion: The result of this study suggests that subjects who have CAI do not have deficit in knee JPS when tested in sitting position and also under functional weight bearing conditions.  

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Background and aim: The ability to maintain upright stance is essential in gait and initiation of voluntary movements that are vital not only for sport but also for activity of daily living .Lateral ankle sprains are common in athletes and are most prevalent in jumping sports such as volleyball , football and basketball .Although these injuries are common after direct contact. It may occur in non contact mechanism such as landing from a jump. Neuromuscular control plays a major role in dynamic joint stability. Most of ankle joint injuries occur in jump-landing task and at the end of sport activitiesparticularly when the athlete is fatigued. Our purpose was to evaluate the effects of ankle muscle fatigue on dynamic postural stability in jump landing task. 

Material and methods: Twenty two healthy women athletes (age:22.8±1.7 years, height:160.3±4.9 cm and weight:56.2±5.8  kg) volunteered to participate in this study .Two test sessions were done with a rest period of one week between them . During each session, effect of one group of ankle muscles (sagital or frontal movers) on dynamic postural stability was assessed. Postural stability was evaluated for 5 seconds after landing on force plate by postural stability indices ( Medial/Lateral, Anterior/Posterior, Vertical and Dynamic Postural Stability Indices) before and after isokinetic fatigue of ankle muscles.

Results: The finding indicate significant increase in all stability indices after isokinetic fatigue of ankle muscles (p<0.05).

Conclusion:These results indicate that isokinetic fatigue of ankle muscles significantly decrease postural control ability in healthy women athlete. 

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 Background and Aim: The common mechanism for lateral ankle sprain is inversion, plantar flexion, or the combination of both, if untreated successfully can lead to chronic ankle instability. It seems that the foot position, while touching the ground, has an effective role to cause ankle sprain. Thus it is possible to prevent ankle sprain through limiting foot position. Therefore the aim of this research is to study the effect of plantar flexion and eversion on mediolateral ground reaction force while landing in individuals who suffering from functional ankle instability.

Materials and Methods: In this case-control research study 32 subjects (17 subjects with unilateral functional ankle instability (FAI) and 15 control subjects), aged from 18 to 35 years, were tested. All subjects in instability group were selected by the orthopedic physician, then the anterior drawer and talar tilt tests were  performed for diagnosis of functional ankle instability and other physical examinations. Control group were matched with instability group by age, weight, height, gender and body mass index. The subjects standing with single leg on a 40 cm high platform in 25 cm front of a force-plate while the test leg relaxed and non-weight bearing. The subject landed on the test leg on the center of the force-plate. The subjects landed according to four types of position: A: neutral position of ankle and lateral foot wedge, B: neutral position of ankle, C: positive heel and lateral foot wedge and D: positive heel. 

Results: Among control group, medial ground reaction force increased in the "C" position relative to "B" position (p=0.007) and "C" position relative to "D" position (p=0.018). In FAI group, lateral ground reaction force increased in "C" position relative to "B" position (p=0.001) and "C" position relative to "A" position (p=0.002). Also in FAI group medial ground reaction force decreased in "D" position relative to "A" position (p=0.014). 

Conclusion: According to the findings, applying lateral foot wedge, while the ankle is in plantar flexion, increases the mediolateral ground reaction forces. Based on the results, position of plantar flexion is more possibly effective than inversion in ankle sprain. According to the study, the lateral foot wedge in ankle plantar flexion position may be more effective than in neutral one to change mediolateral ground reaction forces. 

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Background and Aim: Forces which applied to ankle joint for control of stability can cause damage to joint if it does not have suitable control. Chronic ankle instability (CAI) is a current disability that can affect on activity daily living of the patients. The aim of this study is to evaluate forces which contribute to control of posture in difficult conditions.

Material and Methods: Postural control was measured by force plate in two groups of CAI and healthy subjects. Eight positions were selected , including of double stances with closed or opened eyes, and single stances with opened eyes (right/ left) with and without a cognitive task. Force changes in two direction medial/lateral and anterior/posterior were evaluated with fractal time series analysis.

Results: Fractal dimension of force in two groups, following dual task in all of conditions reduced significantly (P<0.05). There was not significant different between two groups in double stance with or without dual task. Single stance in patients indicated significant increase of fractal dimension in affected ankle joint (P<0.05) but comparison of two side in healthy subjects did not have difference. Also there was significant increase of fractal in affected ankle joint of patients in comparison with similar side of healthy subjects (P<0.05).

Conclusion: Patients with (CAI) have a problem in regulation of force for control of posture. This difficulty increased and clearly indicated by dual task condition, which can cause susceptible qualifications for recurrent injuries. Fractal dimension is a suitable factor for analysis of control of posture in difficult situations.

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Background and Aim: One of the risk factors in sports injuries is inappropriate flexibility of muscles, which leads to pain, decrease range of motion and functional limitation in sport or daily activities and affects the athletes’ quality of life. The aim of this study was to investigate the relationship between flexibility of calf muscles and functional status of athletes with ankle injuries.
Materials and Methods: Thirty male athletes with ankle injuries (mean age ± SD, 22.63 ± 3.94 range: 18-40 years) participated in this study. Ankle dorsiflexion of affected and non-affected sides were measured with a goniometer. FAOS (Foot and Ankle Outcome Score) questionnaire was used to evaluate the functional status of ankle.
Results: The relationship between flexibility of calf muscles in the affected extremity, and total score of the functional questionnaire, was not statistically significant (P>0.05). While the relationship between the flexibility of muscles and functional questionnaire's total score in the non injured extremity was significant (P = 0.004, r = 0.51).
Conclusion: This study revealed that although the athletes who have more flexibility of calf muscles, show better functional status of ankle but there is not necessarily a relationship between inflexibility of the muscles and lowered functional status.

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Bachground and Aim: Ankle sprain is one of the most common injury among the athletic injuries. Around 70-80% of these injuries tend to be chronic. Despite extensive clinical and basic science research, the incidence of Chronic Ankle Instability(CAI) has not significantly reduced. Because the causes of CAI is not quite clear, the rehabilitation still deals with great challenges . one of the treatment methods which has been under special attention for this injuries is Kinesio Taping(KT). In this study, effects of three KT methods on performance in athletes with CAI was investigated .

 

Materials and Methods: Thirty male athletes (futsall, football) with CAI participated in this study. The KT was used in three distinct times with three different methods (mechanical, functional and ligament- Tendon Correction) for these people and their short- time effects on functional performance of lower limb was evaluated. This evaluation was done thorough two functional performance test (Star Excursion Balance Test and Figure of 8 Hop Test).

 

Results: In taping with the aim of functional and mechanical correction, functional performance after KT dramatically improved but in taping with the aim of Ligament-Tendon correction functional performance did not change significantly after taping.

 

Conclusion: The result of this study suggests that functional and mechanical correction have the significant effect on functional performance of futsaland football athletes with CAI , the ligament-tendon correction has not significant effect.

 

Keywords: Chronic ankle instability, Kinesio tape, Functional performance tests.

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Background and Aim: Many studies investigated the effect of ankle-foot orthosis on reducing the incidence of sprain. In this study the influence of elastic and semirigid stirrup type orthosis on the onset latency of peroneus longus muscle activity as the most important support of ankle- foot region in response to sudden perturbation was assessed in healthy group and athletes with functional ankle instability.

 

Materials and Methods: Thirteen healthy female athletes and 10 female athletes with functional ankle instability (17 to 27 years old) were perturbed unexpectedly by a custom made ankle perturbation system in frontal plane under three conditions of without orthotics, using elastic orthosis, and using semirigid stirrup-type orthosis. Simultaneous recording of electrical activity of peronus longus muscle was performed with surface electromyography.

 

Results: The results showed the significant differences between muscular latency of injured and control groups without orthosis (P=0.018). The onset latency reduced using each type of the orthoses in injured group but it was not significant (P>0.05).

 

Conclusion: Although the latency time of peroneus longus muscle response delay didn’t show significant reduction using orthoses in injured group, it seems that using orthoses leads to proprioception improvement and sensiomotor control increasement by stimulation of cutaneous mechanoreceptors.

 

Key words: Functional ankle instability, Invertory perturbation, Electromyography, Orthosis

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Background and Aim: In recent years, introducing the quantitative methods for diagnosing the joints injuries and its level of severity, surveying the recovery progress and effectiveness of rehabilitation methods are important for clinical practice. Using the inertial sensors is one of the custom methods for quantifying joints motion. The purpose of this study is to quantify injuries in ankle joint.

 

Materials and Methods: By setting the Sharif-HMIS inertial sensors on the leg and ankle of patients and control subjects, the motion of their ankle was evaluated and the amount of velocity and acceleration in 8 distinct motions were measured.

 

Results: Using the gathered data from the sensors in different motions and by implementing the assumed criterions, several parameters are calculated that can give a rather precise and quantitative distinction between injured people and control subjects. The results showed that RAV, M and P scores indicate the differences between patients and control subjects clearly, although their performance as a parameter for qualifying the level of ankle injuries is not good.

 

Conclusion: Motion analysis of ankle and comparing the results of patients and control subjects showed that the assumed criterions are valid and can be used for diagnosing the ankle injury. Also, this method is utilized to measure the ankle motion of both elderly and young groups and the results showed that this method is suitable for indicating the ankle motion differences between two groups.

 

Key words: Ankle sprain, Motion measurement, Arthritis, Inertial sensors.