Changes on movement control of dart throwing under distance and target weight constraints

The aim of the study was to verify the effects of dart weight and target distance on kinematic variables of the movement control of the underarm dart throwing task. Four women and one man performed the task of throwing a dart at two horizontal circular targets located at 2m (Nt) and 3m (Ft) away, with two different weights, 22g (Ld) and 44g (Hd). On the first phase of the experiment, the human volunteers performed 200 trials per day during four sessions. On the fifth day, it had 40 more trials in a pseudo random order that were recorded and analysed. A high precision camera recorded the kinematic variables amplitude of the movement (AOM), release height, movement time, release velocity and release angle, with a frequency of acquisition of 100 Hz. Performance was measured by the distance from the actual dart position to the target bull’s eye. The analysis revealed that increasing the mass of the dart diminished only the release angle. However, increasing the distance of the target increased in the AOM and the movement time of the arm, the release velocity of the dart and increased the absolute error. The results show that the motor control system has ability to deal with external constraints adjusting control strategies, which is represented by kinematic features. Moreover, our results suggests that varying the mass of implements, as a constraint may be a good candidate to improve the analysis for both motor control and ability during practice

Out-of-focus Blur: Image De-blurring

Image de-blurring is important in many cases of imaging a real scene or object by a camera. This project focuses on de-blurring an image distorted by an out-of-focus blur through a simulation study. A pseudo-inverse filter is first explored but it fails because of severe noise amplification. Then Tikhonov regularization methods are employed, which produce greatly improved results compared to the pseudo-inverse filter. In Tikhonov regularization, the choice of the regularization parameter plays a critical rule in obtaining a high-quality image, and the regularized solutions possess a semi-convergence property. The best result, with the relative restoration error of 8.49%, is achieved when the prescribed discrepancy principle is used to decide an optimal value. Furthermore, an iterative method, Conjugated Gradient, is employed for image de-blurring, which is fast in computation and leads to an even better result with the relative restoration error of 8.22%. The number of iteration in CG acts as a regularization parameter, and the iterates have a semi-convergence property as well.Comment: 11 page

Changes on movement control of dart throwing under distance and target weight constraints

The aim of the study was to verify the effects of dart weight and target distance on kinematic variables of the movement control of the underarm dart throwing task. Four women and one man performed the task of throwing a dart at two horizontal circular targets located at 2m (Nt) and 3m (Ft) away, with two different weights, 22g (Ld) and 44g (Hd). On the first phase of the experiment, the human volunteers performed 200 trials per day during four sessions. On the fifth day, it had 40 more trials in a pseudo random order that were recorded and analysed. A high precision camera recorded the kinematic variables amplitude of the movement (AOM), release height, movement time, release velocity and release angle, with a frequency of acquisition of 100 Hz. Performance was measured by the distance from the actual dart position to the target bull’s eye. The analysis revealed that increasing the mass of the dart diminished only the release angle. However, increasing the distance of the target increased in the AOM and the movement time of the arm, the release velocity of the dart and increased the absolute error. The results show that the motor control system has ability to deal with external constraints adjusting control strategies, which is represented by kinematic features. Moreover, our results suggests that varying the mass of implements, as a constraint may be a good candidate to improve the analysis for both motor control and ability during practice

Transition I efficiency and victory in volleyball matches

The present study investigated the correlation between Transition Iwith victory in volleyball matches. The 2002 South-American Youth Men's Championship was recorded and the Transition I was analyzed and classified as negative, null or positive. Results of the efficiency in Transition I was calculated using t test for independent samples and compared to the efficiency between teams during each set and matches. Spearman correlation assessed the relationship between efficiency in each set and results of the matches with the final ranking in the championship. The results showed that the winning teams exhibited higher efficiency in Transition I, as well as a positive relationship of higher efficiency in Transition I with all of their results. The higher efficiency in Transition I is related to victory in volleyball matches

High-density lipoprotein-cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides and high-sensitivity C-reactive protein (hsCRP) in male controls (white bars), swimmers (grey bars) and basketball players (black bars).

<p>* indicates difference between the groups (p<0.05).</p

Mean difference between groups on DXA assessments on trunk, upper limbs and lower limbs.

<p>Mean difference between groups on DXA assessments on trunk, upper limbs and lower limbs.</p

Means and standard deviations by group and results of ANOVA to test the effect of sport participation on DXA assessments on trunk, upper limbs and lower limbs.

<p>Means and standard deviations by group and results of ANOVA to test the effect of sport participation on DXA assessments on trunk, upper limbs and lower limbs.</p

Descriptive statistics for variables reporting inter-individual variability on DXA assessments on trunk, upper limbs and lower limbs (n = 53).

<p>Descriptive statistics for variables reporting inter-individual variability on DXA assessments on trunk, upper limbs and lower limbs (n = 53).</p

Means and standard deviations by group and results of ANOVA to test the effect of sport participation on chronological age, maturation, training experience, indicators of lipid profile plus inflammatory biomarker, anthropometry of the overall body size and outputs of whole body DXA assessments.

<p>Means and standard deviations by group and results of ANOVA to test the effect of sport participation on chronological age, maturation, training experience, indicators of lipid profile plus inflammatory biomarker, anthropometry of the overall body size and outputs of whole body DXA assessments.</p