ANALYSIS OF LEFT ARM SEGMENTAL CONTRIBUTION IN GOLF SWING

The object of this study is to examine the segmental movement of the left arm in a golf swing and determine its contribution to the final club head speed. In order to examine this movement, a procedure for quantifying joint movement was developed. Electrogoniometers (Biometrics, UK) with frequency of 1000 Hz were attached to the subjects during the execution of the swing to obtain the joint angles throughout the motion. The velocities of the segment rotation can be computed with dual velocity analysis. A zero handicapper was tested with the method. The method uncovers the importance of longitudinal segmental rotations in his swing. These rotations are often neglected in 2-dimensional approaches

FINGER AND THUMB FORCES DURING BOWLING SHOTS

The purpose of this study was to measure the forces exerted to a bowling ball by thumb and fingers during two different shots. For this task, an instrumented bowling ball was designed and produced, which allowed for force measurement and display of vector diagrams. The highest force is applied by the thumb (up to 120N), followed by middle and the ring finger. The overall moment applied to the ball by thumb and fingers during twisting of the ball reaches 3 Nm

Comparative grading scales, statistical analyses, climber descriptors and ability grouping: International Rock Climbing Research Association position statement

The research base for rock climbing has expanded substantially in the past 3 decades as worldwide interest in the sport has grown. An important trigger for the increasing research attention has been the transition of the sport to a competitive as well as recreational activity and the potential inclusion of sport climbing in the Olympic schedule. The International Rock Climbing Research Association (IRCRA) was formed in 2011 to bring together climbers, coaches and researchers to share knowledge and promote collaboration. This position statement was developed during and after the 2nd IRCRA Congress which was held in Pontresina, in September 2014. The aim of the position statement is to bring greater uniformity to the descriptive and statistical methods used in reporting rock climbing research findings. To date there is a wide variation in the information provided by researchers regarding the climbers’ characteristics and also in the approaches employed to convert from climbing grading scales to a numeric scale suitable for statistical analysis. Our paper presents details of recommended standards of reporting that should be used for reporting climber characteristics and provides a universal scale for the conversion of climbing grades to a number system for statistical analysis

Mobile Computing with a Smart Cricket Ball: Discovery of Novel Performance Parameters and Their Practical Application to Performance Analysis, Advanced Profiling, Talent Identification and Training Interventions of Spin Bowlers

Introduction: Profiling of cricket bowlers is performed with motion analyses systems that require the placement of markers on the bowler’s body and on the ball. Conventional smart balls such as cricket and baseballs provide only one speed and one spin rate datum at the release point, which is insufficient for biomechanical profiling. Method: In this study, we used an advanced smart cricket ball that measures the angular velocity at 815 Hz and calculates four further physical performance parameters (resultant torque, spin torque, power and angular acceleration) and five new skill parameters (precession, normalised precession, precession torque, efficiency and ratio of angular acceleration to spin rate), which we used for profiling and talent identification of spin bowlers. Results: The results showed that the spin rate is a function of physical (torque) and skill proficiency, namely how efficiently the torque is converted to angular velocity rather than being wasted for precession. The kind of delivery also influences the efficiency, as finger-spin deliveries were less efficient than wrist-spin ones by 6.8% on average; and topspin deliveries were generally more efficient than backspin ones by 15% on average. We tested three bowlers in terms of physical and skill performance during a 10-over spell, revealing that some parameters can improve or decline. When profiling a topspinner, we detected from the performance parameters a lower skill performance than expected, because there was an initial arm motion for backspin delivery before releasing the ball with a topspin. After training intervention, the skill parameters improved significantly (the efficiency increased from 39% to 59%). Conclusions: The advanced smart cricket ball is a classic example of mobile computing for sport performance analysis that can conducted indoors as well as outdoors, generating instant data from 10 performance parameters that provide critical feedback to the coach and bowler

Biomechanics of sport climbing

The main goal of the project is to contribute to climbing research through biomechanical analysis of real sport climbing situations rather than relying on laboratory experimental set-ups outwith climbing gyms and facilities. Thus, most of the studies presented in the subsequent chapters were done at different climbing facilities in Singapore. Most studies in the subsequent chapters are carried out with piezoelectric force sensors, attached to climbing holds, for force measurement, and subsequent analysis of mechanical parameters and visualisation of vector diagrams. The evaluation of the mechanical parameters and the interpretation of the results is crucial for the measurement of performance, optimisation of equipment, and improvement of training, as well as for climbing in becoming an Olympic sport.SUG 12/0

Vibrations Affecting Stability and Edge Control of Snowboards

Background: During a carving turn, vibrations are induced at the heel of the snowboard through edge friction when the heel slips sideways and subsequently travel through and along the board to the shovel, which vibrates and affects the edge control. The purpose of this study was to find a method for assessing the edge grip with a laser vibrometer. Method: Two boards, loaded and tilted at four different angles, were placed on a soft surface, with a shaker connected to the heel at the hindmost edge point. The shovel and particularly the frontmost edge point were scanned with a Polytec laser vibrometer. The frequency response functions of coherence, average shovel displacement, and displacement of the foremost edge point were recorded, and the latter was integrated for obtaining an edge mobility measure (EMM) to quantify the edge control. Results: Of the two boards compared, the shovel of board A was stiffer in the 1st and in the 3rd torsional mode, and the one of board B was stiffer in bending modes. The 2nd torsional mode was responsible for large edge vibrations and therefore for a diminished edge control. Shovel B had a smaller EMM at greater tilt angles, that is, less amplitude of the vibrations at the frontmost edge point, and therefore a better edge control. Shovel A, however, had a smaller EMM at smaller tilt angles. Conclusion: The method developed in this study provides a reliable test for assessment of edge control of a snowboard under standardized test conditions

The Dynamics of a Turning Ship: Mathematical Analysis and Simulation Based on Free Body Diagrams and the Proposal of a Pleometric Index

This study attempts to shed new light on the dynamics of a turning ship using the principles of free body diagrams (FBDs). Unexpectedly, the literature gap is defined by incomplete and flawed FBDs. The method behind this new approach involves the FBD of a turning ship, with all the essential forces included, namely propulsive force, sideward thruster force (producing the initial turning moment), drag force, lift force, centrifugal force, inertial force, and hydrodynamic force couple. From these forces, the force and moment equations are derived. The accelerations are calculated from the force and moment equilibria to simulate the dynamics from input parameters such as mass m, length L, draught D, and fluid density ρ. The turning dynamics are explained in terms of velocities, accelerations, forces, and moments, based on two conditions: flat and steep angles of attack (AoA) and long and short turning radii R. A critical result is the proportionality of lift and centrifugal forces, leading to the proposal of a pleometric index (m·L–2·D–1·ρ–1), which is nonlinearly proportional to the product of AoA and R/L, characterising the dynamics of a turning ship. The FBD approach of this study also identified missing databases required for accurate simulation of turning dynamics, such as drag and lift coefficients of different hull geometries