A THREE-DIMENSIONAL KINEMATIC ANALYSIS OF THE FRONT FLY-CAST

Abstract

A fly caster must control the entire length of line to be projected while casting. This requires coordination of shoulder, elbow, and wrist movement. Little quantitative kinematic research describing the basic front fly cast has been published to date. The purpose of this study was to provide a three dimensional kinematic description of expert performance of the front fly cast, and to compare the results to fly casting instructional media. Twelve club level fly fishing experts, able to accurately cast with standardized equipment to a one meter target circle 12.9m away, were chosen as subjects. Each subject was videotaped indoors while performing five accurate basic front casts from a standard reference position. Two genlocked video cameras operated at 60 Hz were used for collection of the three-dimensional calibration frame and casting images. After data collection, seven body and rod handle reference position markers were digitized frame by frame for each camera view. The Direct Linear Transformation algorithm was utilized to provide the three dimensional coordinate locations of the markers. Within subject reliability data values obtained by analysis of two different casts from three randomly selected subjects demonstrated congruity between casts for the kinematic variables. The mean, standard deviation, standard error, and range of the quantified variables were reported and compared to the qualitative description of these variables in instructional publications. The group results revealed a consistent pattern of angular displacement and angular velocity among subjects for rod position to horizontal, elbow, wrist, and torso motion. Dissimilarities were noted for sagittal and frontal plane shoulder motion, and for rod displacement from the sagittal plane. Comparison of the study results to the qualitative descriptions of instructional authors revealed several differences. Subject data exhibited higher initial, midpoint, and ending rod position to horizontal angular displacements, and exhibited greater rod displacement from the sagittal plane, than the descriptions of these variables in the casting literature. More flexion at the elbow and less flexion at the shoulder were exhibited at the end of the backcast by the subjects than was described in the casting literature. The results of this study provided quantitative data for validation of current and future descriptions and analyses flycasting mechanics.