Effect of Balance Training on Muscle Electrical Activity in Subjects with Functional Chronic Instability

INTERVENTION: E02.779.483 Study participants underwent two experiments , one which aimed to investigate the balance of the participants and the other was to investigate the electrical activity of the muscles studied . In Experiment 1 , participants in the standing position (standing ) on the force platform in one foot ( on the leg with CAI ) , were instructed to cross their arms across her chest and focus on a point 4 meters ahead in eyes open condition . They did the same task with eyes closed . There were 5 trials in each condition ( eyes open and eyes closed ) with a duration of 10 seconds for each attempt. In experiment 2 , subjects performed the task of kicking a ball ( external disturbances of posture ) . In this experiment , subjects were placed bare on one foot, with hands on hips on the leg with CAI . As the ball was thrown always the same distance and height , subjects received the same disturbances during all experimental conditions. There were 5 attempts (five releases the ball ) for each of the conditions / collection surfaces ( stable and unstable ) . CONTROL GROUP : 22 individuals did not undergo any kind of training ; GROUP INTERVENTION (training ) : 22 subjects underwent a protocol of balance training , where the degree of neuromuscular requirement was gradually increased over a period of 25 minutes . During this protocol the evaluator left the room and returned only after 25 minutes (do not know who carried out the treatment) . The balance training protocol was composed of five steps , described below : 1 ) Heating : 2 minutes = Dorsiflexion ‐ platiflexão ( foot down and up) , inversion ‐ eversion (foot sideways) ankles . 2 ) progressive balance exercises : 5 sets of exercises in each series were performed 15 kicks , totaling 75 shots . Initially the participants were on a stable surface , with both feet on the ground ( bipedal support ) and were instructed to kick the ball thrown by a research assistant . After they were in one foot ( on one leg ) and performed the same ta CONDITION: C05.550.521 Chronic Ankle instability; Postural Balance ; C05.550.521 ; G11.427.690 G11.427.690 PRIMARY OUTCOME: Modifications of the integrals of the electromyographic activity (EMG)of the following muscles: soleus (SOL), gastrocnemius (medial ‐ lateral and gasm ‐ GasL), peroneus longus (FL), tibialis anterior (TA) , rectus femoris (RF)and biceps femoris (BF), with the balance training. The values were obtained during the task of kicking a ball, immediately pre‐and post‐intervention. INCLUSION CRITERIA: aged 18 to 30 years of age; history of two or more ankle sprains, with at least a sprain in the last six months; sensation of ankle instability, ie, the feeling that the ankle "out of place" during functional activities (work, leisure and / or sport); and score below 28 on the validated Portuguese‐Brazil version of Cumberland Ankle Instability Tool. SECONDARY OUTCOME: Increase in displacement of the body center of pressure (COP) dynamic measured during the task in which the individual had to kick the ball thrown immediately pre‐and post‐intervention. Magnitude of the integrals of the electromyographic activity (EMG) onset (beginning) and latency muscle (LM) of the following muscles: soleus (SOL), gastrocnemius (medial ‐ lateral and gasm ‐ GasL), peroneus longus (FL), tibial anterior (TA), rectus femoris (RF), biceps femoris (BF) and adductor (AD), modified with balance training, when evaluated individually. The values were obtained during the task of kicking a ball, immediately pre‐and post‐intervention. Reduction in the displacement of the body center of pressure (COP) semi‐static, measured during task performance in the individual stood on one foot on the force platform for 10 seconds immediately before and after the intervention.