arezou mehranian

The acquisition of motor skills in mentally retarded children is slow. Therefore, it is important to identify efficient and effective methods for teaching motor skills to these people in order to acquire and improve the implementation of motor skills. Therefore, the aim of the present study was to investigate the effect of variable training with different arrangements on the consolidation (based on improvement) of the motor memory of mentally retarded children.

For this purpose, 56 mentally retarded girls were placed in four groups of fixed training and variable training with blocked, random, and blocked-random arrangements based on the pre-test scores. On the first day, the subjects practiced the basketball pass in 3 blocks of 12 attempts based on the training method of their group. At the end of the training session, the subjects immediately participated in the acquisition test, consisting of a block of 12 target throwing attempts. In the morning of the second day, after a night's sleep, a memory test similar to the acquisition test was performed. For data analysis, a mixed analysis of variance (2x4), a dependent t test, and a one-way analysis of variance were used.

The results of the present study showed that before and after night sleep, there is a statistically significant difference in the passing accuracy scores of the two groups of random variable training and blockedrandom variable training. However, no difference was seen between the performance of the two groups of random and blocked-random training after night sleep.

Therefore, in mentally retarded children, the method of variable training with random and blockedrandom arrangements can be used to improve the consolidation of motor memory.

Job fatigue is considered one of the factors affecting the performance and the productivity of workers in work environments. Therefore, the objective of the present study was to investigate the relationship between job fatigue and its dimensions with fine motor skills in the production line workers of Sabzevar Cable Car Company.

One hundred and forty-eight workers of the production line of Sabzevar Car Company were selected as a sample. The level of occupational fatigue of workers was measured using the standard questionnaire of Excessive Occupational Fatigue. In addition, manual and sorting skills of workers were estimated through Board test. In order to analyze the research data, Spearman's correlation coefficient test was used.

The results of the Spearman correlation coefficient test showed that there were negative and significant relationships between job fatigue and the components of hand and finger dexterity skill, including manual skills (r = 0.188, P ≤ 0.022) and sorting skill r (r = -0.246,  P ≤ 0.003). Also, a statistically significant relationship was observed between the dimensions of fatigue and coping skills (P≤0.05).

According to the results of the present research study, we recommend that employers prevent the occurrence of worker fatigue in industrial environments through providing conditions such as shift breaks and performing short-term activities with low intensity. Otherwise, in order to prevent accidents and the production of defective products, tired workers should refrain from performing fine manual activities such as assembling.

as getting old, neuromuscular adaptations decrease and the fall rates increase. Analyzing the temporal patterns of muscle synergy can provide a useful framework for describing and interpreting neuromuscular system’s adaptation. Therefore, the aim of the present study was to investigate the effect of unstable resistance training with blood flow restriction on the temporal patterns and the number of muscle synergies of elderly with a history of falling while walking.

27 elderly men (62±1.5 years old) with a history of falling were randomly assigned into three groups of unstable resistance training without blood flow restriction, unstable resistance training with blood flow restriction and control. The training program consisted of squat training with body weight on unstable surface for 4 weeks and three sessions per week. Before and after the intervention, electromyography signals from eight muscles of the lower limb were recorded during walking to extract the number of synergies, the amount of muscle use, the duration of muscle use, and the stability of neural commands. Kruskal-Wallis test, Paired Wilcoxon test and analysis of covariance test with Bonferroni post hoc test were used (P˂0/05).

Results showed that although there is significant difference in the number of muscle synergy between the control group and the resistance training group on the unstable surface with blood flow restriction (p=0.002) and without blood flow restriction (p=0.013); But no statistically significant difference was observed between the two training groups (P=0.23). Also, the amount of muscles use and duration of muscles use decreased in both training groups with blood flow restriction (P=0.0001) and without blood flow restriction (P=0.0001). However, statistically significant difference was observed only in the stability variable of neural commands between both training groups with and without blood flow restriction (P=0.005).

Unstable resistance training with blood flow restriction only improves the stability index of neural commands during walking compared to unstable resistance training without blood flow restriction in elderly people with falls’ history.

 older adults show high levels of co-contraction in lower extremities’ muscles due to the deterioration of the neuromuscular and sensory motor systems. Increased co-contraction leads to disruption of daily motor activities, especially movements in which joint stability is critical; therefore, it is important to pay attention to training programs to strengthen muscles and increase intramuscular coordination in older adults. The aim of this study was to investigate the effect of unstable resistance training with and without blood flow restriction on ankle muscles’ co-contraction of older adults.

 27 older adults (62 ± 1.5 years old) were assigned into three groups of unstable resistance training without blood flow restriction, unstable resistance training with blood flow restriction (72± 9 mm Hg) and control. The training program consisted of three to four sets of 15 repetitions of body weight squats for four weeks and three sessions per each week, which were gradually added to the program by 5% of each person's body weight. Pre- and post- intervention, the electromyography signals of Tibialis Anterior and soleus muscles were recorded during walking in order to determine the rates of agonist and antagonist activity and muscles’ co-contraction. For data analysis, repeated measures analysis of variance and analysis of covariance tests with Bonferroni post hoc test were used at 0.05 of level of significance.

 The results showed that in post-test, the activity of the Tibialis Anterior muscle of both training groups was significantly increased compared to pre-test. Also, statistically significant difference was found in co-contraction rates of both groups in post-test. The results of Bonferroni post hoc test showed a statistically significant difference in reduction of co-contraction rates between the resistance training group with blood flow restriction and the control group (P=0.015) and between resistance training group without blood flow restriction with the control group (P=0.005). But no statistically significant difference was found between the two training groups.

 Resistance training on unstable surface with and without blood flow restriction is associated with increased agonist muscle activity, which leads to a decrease in ankle muscles’ co-contraction in older adults.

In recent years sports psychologists, coaches and athletes have paid a greater focus of attention to mental wellbeing and psychological skills. The purpose of this study was to investigate which psychological skills are important to two levels of skills among Darts players, namely; elite and beginner.

The sample consisted of 24 elite and 24 beginner Darts throwers. In order to gain insight into Darts throwing, beginner Darts players attended a national-championship-simulated competition. Both elite and beginner players also completed the Ottawa Mental Skill Questionnaire.

Independent t-test results showed that there was a significant difference just in basic psychiatric skills between the beginner and elite Darts throwers (p<0.05). Nevertheless, there is no statistically significant difference in Ottawachr('39')s mental skills, psychosomatic skills and cognitive skills between beginner and elite Darts throwers (p>0.05).  

Results revealed differences between elite and beginner Darts players in foundation mental skills and commitment and mental practice subscales. Furthermore, results showed that for the commitment skill, elite and beginner Darts throwers were at the highest and lowest level respectively.

Regarding the role of sleep on improving the performance of motor skills, researchers are looking for effective strategies for more effectiveness of night sleep. The aim of this study was to investigate the effect of physical fitness (specific warm-up and neuromuscular facilitation) on consolidation (based on promotion) of students’ explicit motor memory.
Considering the objective, this study is a practical study. Thirty-two eligible male students were selected randomly as the statistical sample in 2016. Based on the pre-test scores, the participants were assigned into three groups of control, specific­ warm-up, and PNF. In the first day, after performing their own group-specific practices and 54 trials of dart throwing, the participants attended the acquisition test (9 trials). Afterwards, in the morning of the second day after the night sleep, test retest (9 trials) was taken. The limb coordination was assessed using NORMSE. The data were analyzed using one way ANOVA and dependent t-test at a level of α=0/05.
The results showed that limb coordination component was significant only in specific warm-up group, before and after night sleep. Furthermore, the results revealed that after night sleep, there is statistically significant difference between control and specific warm-up groups in limb coordination component.
The results of present research showed that the specific­ warm-up exercises before performing dart throw are effective on consolidation (based on promotion) of limb coordination component.

Preparation of neuromuscular system prior to performing motor skills affects the learning of motor skills. The present study was conducted to investigate the effects of Proprioceptive Neuromuscular Facilitation (PNF) on limb coordination and accuracy in dart throwing skill.
Thirty two male students were randomly selected as study sample. Based on the pretest scores, the participants were divided into three groups: experimental (proprioceptive neuromuscular facilitation), first control (without warm-up), and second control (specific warm-up). During the acquisition phase, the participants first performed the preparation training related to their own group, then all groups performed the exercise program of dart throwing consisting of 6 blocks of 9 trials in 4 training sessions. Finally, 20 days following the last exercise session, the subjects took the retention and transfer tests.
The results of one-way ANOVA test for coordination variable in acquisition test showed no significant difference between the groups, while there was a statistically significant difference between groups regarding coordination variable in retention and transfer tests. Furthermore, the results of one-way ANOVA for the accuracy variable in acquisition and retention tests showed no statistically significant difference between the three groups, while there was a statistically significant difference between groups for accuracy variable in transfer test.
It seems that proprioceptive neuromuscular facilitation, as a preparation method before performance, can enhance the efficacy of training to better learn the coordination pattern of fine motor skills.