مجله پژوهش در علوم توانبخشی
سال سیزدهم شماره 5 (آذر و دی 1396)

Proprioception (PP) and balance play a significant role in improving performance and preventing acute and chronic sport injuries. Muscle fatigue can be one of the factors that may interfere with signaling sensory input to the brain, and disturb the balance. The effect of muscle fatigue on this sensation has hardly been studied. The aim of this study was to investigate the effect of erector spinae muscle fatigue on the sensation (PP) of trunk, hip and knee among the male Karate athletes.

10 male karate athletes participating in Iranian national league matches were recruited in this study. Absolute error of active angles reconstruction (the trunk in 45 degrees of flexion, the hip in 30 degrees of abduction and flexion in open kinetic chain, and the knee in 30 and 60 degrees of flexion in closed kinetic chain) was measured by filming and analyzed, using AutoCAD software in pretest and posttest. Sorensen test was used as fatigue protocol.

The t test showed that erector spinea muscle fatigue had a significant effect on trunk flexion in 45 degrees (P = 0.046), and dominant (P = 0.001), and non-dominant (P = 0.001) hip joint in 30 degrees of abduction; but did not have any significant effect on positioning sensation of dominant (P = 0.434) and non-dominant (P = 0.703) hip flexion in 30 degrees, dominant (P = 0.148) and non-dominant (P = 0.204) knee flexion in 30 degrees, and dominant (P = 0.417) and non-dominant (P = 0.439) knee flexion in 60 degrees.

According to the obtained results, erector spinae muscle fatigue in Karate athletes is likely to cause disruption in their trunk and hip position sensations, which can be the probable cause of lower-limbs injury and instability, particularly in the hips. Erector spinae muscle fatigue, however, may have no significant effect on knee position sensation or the injury potential of this joint

Knee osteoarthritis is one of the most common musculoskeletal problems in older women which affects their daily life. It causes balance impairment, and increases the rate of falling in these patients. Therefore, the aim of this study was to compare the effects between tai chi exercise and glucosamine supplementation on the balance of older women with knee osteoarthritis. This was a clinical trial study, in which 75 women with knee osteoarthritis (according to the Kellgren and Lawrence scale) were chosen, and randomly assigned into 3 groups of tai chi exercise (performed 3 times a week for 3 month), glucosamine supplementation (3 times a week), and control (no intervention). Before and after interventions, static balance (measured by stabilometer in both open and closed eye) and dynamic balance [measured by timed up and go (TUG) test] were examined. Paired sample t and ANOVA tests were implemented for data analyzing at a significant level of less than 0.050. Tai chi exercise had a significant effect on static [open (t = 9.57, P = 0.001) and closed (t = 5.30, P = 0.001) eye] and dynamic balance (t = 8.54, P = 0.001); supplementation variable had a significant effect only on dynamic balance (t = 2.21, P = 0.040); in control group, there was not any significant difference between before and after intervention. Comparing three groups, the ANOVA test showed a significant difference between the exercise and control group in static [open (P = 0.001) and closed (P = 0.001) eye] and dynamic balance (P = 0.040). It seems that tai chi exercises enhance the balance in older women with knee osteoarthritis. It also could be concluded from the results that only the exercise variable has the significant effect on subject’s balance compared to glucosamine supplementation.

Determining non-dominant leg in balance researches is important. Due to lack of specific test for determining non-dominant leg, the researchers had determined dominant leg, and then considered the opposite leg as non-dominant leg. Since, the used method had some drawbacks, the purpose of the present study was to evaluate the correlation and reliability of tests for determining non-dominant leg. 28 women were selected through purposeful sampling method among the students aged 18-25 years in Alzahra University, Tehran, Iran, and participated in this study. Field and laboratory tests included tests for determining preferred leg during stability task, functional test of stability task, single-leg stance balance tests, and weigh distribution on legs test during double leg stance. In order to study the manner of weight distribution on legs, a force plate and motion analysis system were used. MATLAB software was used for data analysis, and statistical analysis was done using SPSS software. Highest correlation (r = 0.85) was related to two tests of hopping and landing from height (P = 0.001). There was also moderate correlation between hopping (r = 0.40) and landing from height (r = 0.47) tests and hopping distance test (P = 0.005). Results of reliability of tests revealed that only these three tests have high reliability. When method for calculating average values of trials was somehow modified, small but significant correlation appeared between single-leg stance test with landing (r = 0.28) and hopping skill distance (r = 0.29) tests (P = 0.020). There was no significant correlation between double leg stance test with stability task and single leg stance balance tests. Tests for determining non-dominant leg should be proportionate to task in research. Single-leg stance balance test used in the present study had not acceptable reliability, and based on the stability task and balance single-leg stance tests used in this study, manner of weigh distribution on legs at double leg stance condition cannot be shown

  The influence of using safety headgears on important parameters of head injury in taekwondo has not been specified yet. The aim of this study was to investigate the amount of changes in rotational acceleration, linear acceleration, and impact force of head by using headgears in taekwondo. In this experimental study, 14 elite men taekwondo athletes participated. To investigate the effect of headgears on head injury parameters, a machine was used that consisted of an artificial neck and head, a mechanical arm that represented the taekwondo athlete foot, and a computer system for monitoring, supervisioning and recording the data, that was made by the researcher. The results were obtained in the MATLAB program. One-way repeated measures ANOVA and Bonferroni tests were applied to analyze the statistics results (P < 0.050). All headgears significantly reduced the impact force and linear acceleration of the head (P = 0.001). Foreign headgears and Iranian headgears significantly decreased and increased rotational acceleration, respectively (P = 0.001). All headgears are good protectors for preventing injuries due to impact force and linear acceleration. But, none of these headgears could reduce rotational acceleration to less than the threshold of head injury

Anterior cruciate ligament rupture (ACL) is the most common knee ligament injury. In addition to the high cost of treatment, it causes loss of athletic participation, and tend to secondary damages. Deficiency balance is one of the most important causes of this injury, so balance improvement can prevents it. Therefore, the purpose of this study was to investigate the effect of eight weeks of neuromuscular training on balance and prevention of ACL injury in boy adolescent taekwondo players. Twenty-seven boy adolescent taekwondo players participated in this study voluntarily. They were divided into two groups of experimental (n = 15) and control (n = 12). The experimental group performed neuromuscular training sessions of 30-45 minutes, three times per week, for 8 weeks, and in the rest of the time (up to 90 minutes), they performed usual taekwondo trainings. The control group only practiced usual taekwondo trainings for 90 minutes. Static and dynamic balance was measured using the Biodex balance system before and after applying the neuromuscular training protocol. The comparison of the groups was done using the ANCOVA statistical method at a significant level of P < 0.050. There were significant differences in the static balance index (P = 0.001) and all of the dynamic static balance indexes [posterior-anterior index (P = 0.001), external-internal index (P = 0.001), and general index (P = 0.001)] between the groups after performing neuromuscular training. It can be suggested that, neuromuscular training have a positive effect on the balance in boy adolescent taekwondo players, and may prevent ACL injury.

Postural control changes with ageing, and it is essential to study aging-related mechanisms. The aim of this research was to investigate the effects of gender, and functional and cognitive training on balance control in middle-aged people. This was a practical study with subimpirical method. The participants were 80 middle-aged people (40 men and 40 women), who were selected according to inclusion criteria, and randomly assigned to eight groups of internal and external focus guidelines in cognitive and functional supra-postural tasks. The postural status was evaluated by measuring the alignment of centre of gravity (COG) through a master balancing system using modified clinical test of sensory interaction and balance (mCTSIB). Based on one-way analysis of variance, men and women who took the focal point of external attention in both functional and cognitive tasks had better postural control (P = 0.002). Men with external focus in functional task had better postural control than the other groups, and Women with internal focus in cognitive tasks had the weakest postural control function. Totally, men in functional and cognitive tasks had a better postural control function than women (P = 0.002). Adopting functional supra-postural strategy is better than cognitive supra-postural strategy in both middle-aged men and women in order to maintain balance. Regarding the fact that women with cognitive tasks with internal focus showed a significant difference in postural control than other groups, it is advisable to focus on stress management methods under stressful conditions for instructors. It seems that these findings are useful for mentors and therapists to design equilibrium exercises by considering age, gender, and type of attention instruction to avoid falling and performing dual tasks

Medial tibial stress syndrome or shin splints is one of the most common overuse injuries in active people, that its risk factors are unknown. On the other hand, leg stiffness is a modifiable mechanical property that may be related to overuse injury. So, the aim of this study was to investigate the role of the leg stiffness in the prediction of medial tibial stress syndrome in active people. 80 students in physical education (50 girls and 30 boys) were selected in a convenience manner. Before the start of training sessions, the stiffness of both legs was measured. During the sessions, injured‏ people were examined, and the type of injury registered by the orthopedic physician. At the end of the training sessions, the subjects were divided into two groups of injured and non-injured. The independent t-test was used to compare the leg stiffness between the two groups. Binary logistic regression was used to investigate the role of leg stiffness in the prediction of the occurrence of this syndrome. There was a significant difference in leg stiffness between the two groups (P = 0.001). Logistic regression analysis revealed that injured subjects had a significantly more leg stiffness‏ before the injury compared to‏ non-injured group. So, leg stiffness was a risk factor this syndrome. This study showed that leg stiffness could predict medial tibial stress syndrome or shin splint. So, high leg stiffness may increase the risk of overuse injuries. This research provides important information to the coaches and team doctors about the management of injury and its treatment.

Movement is the main identity and the base of knowledge and practice in physical therapy; thus, the advances in motor control science, and motor learning and development are linked to physical therapy clinical activity. The purpose of this narrative review article was to describe a prominent approach in motor control with potential to better understanding and diagnosis of movement dysfunctions, the uncontrolled manifold (UCM).

In this narrative review, databases such as PubMed, Web of Science, and Google Scholar were searched from 1999 till 2017, using the key words “Synergy”, “Uncontrolled Manifold”, “Motor Control”, and “Anticipatory Synergy Adjustment”.

Finally, 37 studies were included. Most studies discussed the degree of freedom problem in human movements, history of synergy, characteristics of synergy, introducing the uncontrolled manifold approach as a tool for quantifying the synergy, and clinical applications of this method in the assessments of movement dysfunctions.

Using this method provides the ability to identify the connections between functional activities with motor synergies, synergy strength index, and the anticipatory synergy adjustments. The uncontrolled manifold offers a science-based approach to guide clinical decision making on whether synergies have to be broken, reinforced, or created new synergies in patients with movement dysfunctions.