Abdul Hafidz Omar

KIHECT©: Reliability of Hand-Eye Coordination among Rugby Players Using Consumer Depth Camera

Rugby is a growing sport in the whole world. For athletes who want to achieve a high level of potential, such as hand coordination skills and speed of reaction (sport) both are expected to be in good performance. The main problem in many sports is that there is no test for the reliability of the developed test tools. Thus, the aim of this study is to determine the reliability of the tests, so the research was conducted twice with an interval of 6-7 days (test-retest). A total of 33 rugby players (16-18 years of age) have participated in the study. The analysis includes one motor tasks performed only with the use of KIHECT©. Thus, this study was conducted on a differentiated time and score through two methods of evaluation test: automatically and manually in order to obtain the level of reliability of the tools. The hardware and software that were used in this research are Kinect camera 360, windows SDK and computer or monitor use by CPU systems. The average values of the resultant p-values (<0.005) showed that the instrument is reliable and practical to be used in research area. A test on KIHECT© displayed sufficient reliability to see the difference in score data using automatic method (evaluation score using KIHECT© and manual method (evaluation score of the two observers). Therefore, it can be implemented as a tool to train the hand-eye coordination in rugby games.

New Device for Intrinsic Hand Muscle Strength Measurement: An Alternative to Strain Gauge Handheld Dynamometer

An accurate measurement of intrinsic hand muscle strength (IHMS) is required by clinicians for effective clinical decision-making, diagnosis of certain diseases, and evaluation of the outcome of treatment. In practice, the clinicians use Intrins-o-meter and Rotterdam Intrinsic Hand Myometer for IHMS measurement. These are quite bulky, expensive, and possess poor interobserver reliability (37–52%) and sensitivity. The purpose of this study was to develop an alternative lightweight, accurate, cost-effective force measurement device with a simple electronic circuit and test its suitability for IHMS measurement. The device was constructed with ketjenblack/deproteinized natural rubber sensor, 1-MΩ potential divider, and Arduino Uno through the custom-written software. Then, the device was calibrated and tested for accuracy and repeatability within the force range of finger muscles (100 N). The 95% limit of agreement in accuracy from −1.95 N to 2.06 N for 10 to 100 N applied load and repeatability coefficient of ±1.91 N or 6.2% was achieved. Furthermore, the expenditure for the device construction was around US

Analysis of hydrodynamic force acting on commercialized rowing blades using computational fluid dynamics

53. For a practical demonstration, the device was tested among 16 participants for isometric strength measurement of the ulnar abductor and dorsal interossei. The results revealed that the performance of the device was suitable for IHMS measurement.

Effect of String Tension Toward Racket Performance

This paper presents a study of the hydrodynamics of several rowing blade designs. The study was done using Computational Fluid Dynamics (CFD) which enabled the investigation to be done similar to the experimental study, but with additional hydrodynamic visualization for further analysis and understanding. The CFD method was validated using quasi-static experimental data from Caplan (2007). Besides that, the proposed CFD analyses have improved the precious CFD results with the percentage of error of 6.58 percent of lift and 0.69 percent of drag force compared to 33.65 and 18.75 percent obtained by Coppel (2010). Consequent to the successful validation, the study then proceeded with the real size of Macon, Big balde and Fat blade. It was found that the hydrodynamic performance of the Fat blade was the highest due to the area, aspect ratio and the shape of the blade. Besides that, distribution of pressure for all models were also investigated which deepened the understanding of the blade fluid mechanics of r...

Coefficient of Restitution in Badminton Racket

This chapter provides the analysis of the effect of string tension toward badminton racket. Generally, string tension is one of the crucial parameters on the racket that influences the values of coefficient of restitution (COR) in badminton racket. Therefore, several finite element simulations were carried out to determine the relationship between string tension and deflection of string. The simulations were carried out in varying string tension in order to measure the maximum rebound height and to determine the value of COR. From the finding, the reducing values of string tension leads to higher values of COR. This finding will contribute to the enlargement of sweet spot in badminton racket as well as improving the player performances.

Head Shape Design Analysis of Conceptual Badminton Racket

This chapter explains in greater detail on the development of generating the finite element model for badminton racket using ABAQUS (Explicit). Among the details involved material selections, measurement and important boundary conditions of the finite element models were presented. Several relevant theories behind the analysis of the badminton racket’s performance, such as the equation of coefficient of restitution, COR in badminton racket were explained. Other than that, the important information about the experimental procedures and apparatus setup were explained in detail. The experimental analysis is crucial since the results will be used to validate the finite element model.

Stiffness of Badminton Racket

In this chapter, various racket head designs were evaluated to identify the parameter that influences the performance of the racket. Based on the analysis, performance of racket head design was affected by two main factors which are the area of string-bed and the deflection of sting. In-depth analysis on the relationship between string-bed surface area and deflection of string were discussed in greater details. Furthermore, this finding provides the understanding in development for greater head shape design in future.

Finite-Element Study on Effect of String Tension toward Coefficient of Restitution of a Badminton Racket String-Bed

In this chapter, the effects of racket structural stiffness toward racket performance were widely discussed. Parametric studies were conducted using a validated finite element model of badminton racket consist of various shafts cross-sectional designs and lengths to determine the correlation between shaft design and racket structural stiffness toward racket performance. Based on the results, the design of racket shaft influence the structural stiffness of badminton racket and had a significant effect on the racket performance. The research finding shows a good argument that helps in the development of racket shaft design.

Grounded Theory: A Short Cut to Highlight a Researchers' Intellectuality

Understanding of racket parameters is important for players to gain the best racket which could improve their games performances. This present study was aimed to investigate the effect of string tension toward performance of coefficient of restitution (COR) by neglecting the effect of racket frame stiffness. A finite element simulation of collision between ball and string-bed was performed in Abaqus explicit. The ball was dropped onto the centre of mass (CM) of the string-bed area with different values of string tension. From the results, the increasing values of string tension lead to increase values of COR. This finding will contribute to the enlargement of sweet spot in badminton racket as well as improving the player performances.