The Neurophysiological Effect of Attentional Focus as a Function of Expertise in Postural Task

Background: Examining effects of attention on motor performance at the neurophysiological level, considering the skill level, seems there are still ambiguities. Objectives: The purpose of the present study was to examine the neurophysiological effect of Attentional Focus on in postural task as a function of skill level. The performance (postural sways) and muscular activity changes was recorded shift concurrently in two attentional conditions. Methods: 20 gymnasts (19-26 Years old) participated and assigned to groups of skilled (10 years’ experience) and novices (3-5 years history of training in Gymnastics). All participant of both groups performed ten trails of semi-dynamic balance (10 seconds) in tow conditions of internal and external focus in a counterbalanced order. Postural sways were measured using Biodex Stabilometer and Electromyography (EMG) signals of Tibalis Anterior and Soleus muscles recorded using ME6000 device. Data were data were analyzed using 2×2 mixed ANOVA. Results: Results showed higher performance (less postural sways) and reduced EMG under external focus condition for novices and lower EMG activity for experts. Conclusion: Research findings (enhanced performance and reduced EMG) support Constraint action hypothesis. Focus of attention can have profound effects on motor behavior and the underlying neurophysiologic factors regardless of skill level but in behavioral level of analyze it effects depended on expertise

Hand Fatigue Analysis Using Quantitative Evaluation of Variability in Drawing Patterns

Background & aim: Muscle fatigue is defined as the reduced power generation capacity of a muscle or muscle group after activity which can lead to a variety of lesions. The purpose of the present study was to define the fatigue analysis by quantitative analysis using drawing patterns. Methods: the present cross-sectional study was conducted on 37 healthy volunteers (6 men and 31 women) aged 18-30 years. Before & immediately after a fatigue protocol, quantitative assessment of hand drawing skills was performed by drawing repeated, overlapping, and concentric circles. The test was conducted in three sessions with an interval of 48-72 hours. Drawing was recorded by a digital tablet. Data were statistically analyzed using paired t-test and repeated measure ANOVA. Result: In drawing time series data analysis, at fatigue level of 100%, the variables standard deviation along x axis (SDx), standard deviation of velocity on both x and y axis (SDVx and SDVy) and resultant vector velocity standard deviation (SDVR), showed significant differences after fatigue (P<0.05). In comparison of variables after the three fatigue levels, SDx showed significant difference (P<0.05). Conclusions: structurally full fatigue showed significant differences with other levels of fatigue, so it contributed to significant variability in drawing parameters. The method used in the present study recognized the fatigue in high frequency motion as well