The effects of 8 weeks of yoga on postural control and the quality of life
Hearing loss is the most common sensorineural defect in humans. The occurrence of prelingual deafness is about 1 in 1,000 births and more than 60% of cases are inherited. Deafness is a heterogeneous disorder and it can occur due to environmental, genetic causes or both of them. Hearing loss is stable or fluctuated disorders in the auditory system and affect human performance. The inner ear is a main member of the sense of hearing and body balance system.
The snail-shaped part of ear is a hearing part of the inner ear. Utricle and saccule and semicircular cannels play an important role in balance system. There is perilymph fluid in the top and bottom of cochlear duct. Semicircle cannel disorder and cochlear disorder or disorder of snailshaped par of 18th cranial nerve impact on balance system negatively. 65% of abnormal function is related to the cochlea and balance. Hearing-impaired children are weaker than hearing children in using their skills. On the other hand, there is a difference between hearing-impaired people and this demonstrates diversity of abilities in hearing-impaired children and the differences in language abilities are due to the degree of hearing loss, type of prosthesis, the beneficial use of residual hearing and quality of hearing rehabilitation training and other factors. Hearing impaired people have problems in coordination and speed of movement and maintenance of body balance. Balance disorder is the main cause of stiff walking, weakness of legs, poor maintenance of balance and hyper-kyphosis.
The balance is a multi-sensory activities. Our sense of balance from embryonic development to adulthood is the result of operations of somatosensory, vestibular and visual systems. It is said that in healthy individuals, somatosensory, vestibular and visual systems provide 70%, 20% and 10% of sensory information necessary to maintain the balance on the stable surface. If people who have vestibular system impaired use their visual and proprioception systems, they can maintain their balance. Generally, body control requires a close partnership between proprioceptive sense and vestibular sense. All daily activities needs balance. Functional balance is taken account as a prerequisite to do a lot of static and dynamic activities that can be seen in daily life and it needs proper interaction between sensory and motor systems. Balance during weight transfer or voluntary movement (dynamic balance) emphasizes on balance responses at the time of imbalance and functional simulation. Dynamic postural control can be defined as performing functional task without engaging a part of supporting surface. Postural control is done using the data collected by mech- anoreceptors in the lower extremities, trunk and mass in the area of supporting surface. There are several factors that can affect one’s ability to maintain or regain their postural control and damage to the nervous system, optic nerve dysfunction, stress, vestibular mechanism and fatigue can be noted as the most important factors. According to WHO, the quality of life is full health status of physical, mental and social aspects. Health-related quality of life means individual’s understanding and feeling of his own life that is described with three physical, mental and social dimensions.
To improve health-related quality of life is the ultimate goal of rehabilitation of people with different health conditions are chronic diseases. According to the definition provided by WHO, quality of life is an individual’s perception of life according to the culture and value system governing his living environment with their goals, expectations, standards and top priorities. Hearing impaired people’s problems are often considered only in terms of the aspect of communication. Although communication problem is a major defect caused by hearing loss but it is possible that other physical problems are associated with hearing loss. In this regard, imbalance due to damage to sensory integration and motor development is one of the defects of most hearing impaired. Hesari et al. (2011) have investigated the effects of core stability training on static and dynamic balance in male hearing impaired students in their study. The results showed that balance training has a positive effect on the balance of the hearing disabled. Komei (2014) has investigated the effect of balance training on static and dynamic balance in hearing impaired students. The results showed the positive effects of training on dynamic and static balance in hearing impaired students. Yoga has been paid attention in order to meet the needs of physical health and inner peace. Doing yoga is effective in healing the wounds and in general, it strengthens robustness. Different good results have been reported by the people who have started to practice yoga in the mid and late years of their lives and with significant physical defects. They can regain their lost strength, flexibility, energy and level of health. According to yoga instructors, there is a positive attitude to life in this sport and this positive attitude promotes health and positive energy in people.
Khazaei et al. (2014) have studies the effects of selected yoga exercises on the dominant and non-dominant leg balance in middle-aged women. The results showed that yoga leads to an increase in static and dynamic balance of both legs and dynamic balance of non-dominant leg has been significantly improved more compared to dominant led but static balance of dominant and non-dominant legs have been increased to the same extent. Toga improves psychological conditions for controlling and managing stress, reducing anxiety and negative emotions and increasing positive emotions. Yoga as a low-cost and effective sport for all age groups, is a training program including Asana exercises (stretching and warm-up exercises) that all the muscles are stretched to the point of pain and muscle contraction and then Pranamaya exercises which have been done in a seated position with straight back and along with deep inhale and exhale with certain and coordinated rhythm and also, with holding breath for a short time to start the next step of exercises and the final stage includes meditation which is done after Pranamaya exercises and includes sleeping in the quiet, breathing with the right rhythm, isometric contractions of large muscles, stretching and relaxing and focusing.
Balance means maintaining good posture in both static and dynamic positions. Balancing is a result of interaction between different body systems, including internal factors (proprioception, hearing and eyesight) and muscular factors. Postural balancing on the static and dynamic conditions includes a balance of stable forces and is the need to receive sensory information from visual system, vestibular systems and somatosensory feedback. Multiple systems, involved in maintaining postural control, consist of musculoskeletal components, internal representations, adaptation mechanisms, sensory strategies and neuromuscular cooperation. Yoga is a type of exercise that takes place in a peace and quiet state and strengthens the muscles, nerves and internal organs and people of any age and with any situation can do it. So, yoga is a unique option for engaging these people in sport activities. At the time of doing yoga, participants pay attention to all the aspects of postural control in addition to controlling their breathing and put their body in good condition according to the exercise. In yoga, focusing plays an important role in increasing participants’ awareness of environment and ability to control their bodies. Despite the importance of improving the health of people with hearing loss, no sufficient studies have been done on it in this age group. Present study has been conducted on the effects yoga on the balance in female hearing impaired adolescents.
Present study has been performed to answer these question: is yoga as effective factor in order to improve the balance in hearing impaired adolescents? Do yoga exercises impact on dynamic and static balance?
This study is quasi-experimental. Its population includes all the 15-17 years old female students of Mir Isfahan high school for hearing-impaired students. The samples were randomly selected by convenience sampling method. A cross-sectional study was performed on 28 female students with severe to profound hearing loss. Their personal information is listed in table1. By examining the medical records of the population, the people with a history of upper and lower extremity injury and spine during the past six months and neuromuscular and skeletal problems were selected and the effects of 8 weeks of Hatha yoga on their static and dynamic balance and quality of life were investigated through pre-test and post-test. Inclusion criteria were: having hearing loss greater than 30 db and less than 90 db, 15-17 age range, female gender, having sensorineural hearing loss, not suffering multi disabilities, not suffering a specific disease, not participating in other sport training. 28 students volunteered to participate in this study. All participants filled in a consent form.
best yoga practice
Firstly, Stork Balance Stand Test and Y test were introduced to the participants. They were explained to participants through body language, facial expressions or being run by the experimenter so that the participants understand how to run the tests. In order to eliminate the effect of learning, each participant was permitted to practice three times before the start of the test. All participants carried out the tests without shoes. The tests were performed in school and at the certain time of the day. During running the test, if any problem was observed, required advice and guidance should be given to participants. Before running the test, the participants were performed stretching and warm-up exercises. The tests were run in a quiet room and without any factor disturbing the participants’ attention. After measuring dynamic and static balance and filling in hearing impaired youth-related quality of life inventory approved by the Social Welfare and Rehabilitation Sciences University, adjusted Hatha yoga exercise program was used for 8 weeks (3 times a week, 75-90 minutes in each session) under the supervision of an experienced coach. In early sessions, the coach dedicated 15 minutes to general warm-up exercises, then, 30 minutes to do asana exercises (physical exercises) and pranayama exercises (breathing exercises) and relaxation (savasana) and during the upcoming sessions, the time of main exercises have been gradually increased (Table 1) (25,26). At the end of 24th sessions, participants were asked to participate in post-test.
The method of measuring static balance
Balance task in this study is to stand on dominant leg (stork stand test) and pick up nondominant leg and to put hands on the iliac crest of the pelvis. The length of time that a person could stand in this situation was recorded by stopwatch and considered as an indicator of individual performance on the balance test (Reliability and validity = 0.66) (21). The errors that stopped the time of test were: lifting hands from the iliac crest of the pelvis, stepping, moving the leg that was on the ground, touching the ground with non-dominant leg and lifting the heel of dominant leg from the ground. It should be noted that the minimum duration was considered 10 seconds. If any mentioned error was seen, the stopwatch would be stopped (All balance tests were performed without shoes and with barefoot) (22). Descriptive statistics were used to classify the data and to calculate the central tendency (mean) and dispersion indicators (standard deviation) and inferential statistics were used to test the hypotheses and ANOVA test was used to investigate differences within the group. All calculations were performed using SPSS V.18 software. Significance level was considered p<5%.
The method of measuring dynamic balance
In order to measure the dynamic balance, Y balance test was used. The validity of Y balance test for lower limbs was reported between 0.85 and 0.91 in the Intra-Rater Reliability and between 0.99 t0 1.00 in the Inter- Rater Reliability (23).
This device consists of a fixed plate that three rods are attached to it at an angle of 120 degrees. There is an animated marker on each graded rod that maximum distance can be achieved by pushing it. Y balance test has three anterior, internal-posterior and external-posterior directions. In order to measure the balance of non-dominant side, firstly, the participant places nondominant leg on the fixed plate and then, in order to achieve the maximum distance, moves his non-dominant leg in the anterior, internal-posterior and external-posterior directions, respectively and then, returns to original condition of test. In order to measure the balance of dominant side, the participant places dominant leg on the fixed plate and uses non-dominant led to achieve the maximum distance. Achieve maximum distance was recorded according to the marker of graded rod. In order to eliminate the effect of learning, each participant was permitted to practice three times before the start of the test. The test was repeated three times for each organ and the highest score achieved for each direction was analyzed and in order to prevent fatigue, two minutes were dedicated for resting between the tests. Also, before starting the test, the dominant legs of participants were identified according to their desire to hit the ball (24, 25). Length
of lower limb affect the achieved distance. For this reason, raw scores of balance based on the length of lower limb were normalized (24, 25). The errors which led to repeat the Y test were: 1- the participant’s inability to maintain her stability on the fixed plate (for example, during the Y test, the free foot touches the ground and/or reliant foot is separated from the fixed plate); 2- free foot is separated from the marker of rod while the marker is moving (throwing the marker); 3- using the marker to maintain the stability; 4- individual’s inability to return free foot to the starting position after achieving the score.
Achieved distance is divided on length of lower limb (cm) and then multiplied by 100 and is calculated as the percentage of the length of lower limb. In Y balance test, in addition to separately considering all three directions, a total score was calculated for dynamic balance as follows:
Total score= (anterior+ internal-posterior + external-posterior)*100/length of lower limb*3
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MA student, Isfahan Islamic Azad University, Iran
Associate Professor, Isfahan University, Iran