Publications by authors named "Sasho J Mackenzie"

The purpose of this study was to investigate the influence of shaft torque (torsional rigidity) on clubhead kinematics and the resulting flight of the ball. Two driver shafts with disparate levels of torque, but otherwise very similar properties, were tested by 40 right-handed golfers representing a range of abilities. Shaft deflection data as well as grip and clubhead kinematics were collected from 14 swings, with each shaft, for each golfer using an optical motion capture system.

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The purpose of this study was to investigate the influence of shaft stiffness on grip and clubhead kinematics. Two driver shafts with disparate levels of stiffness, but very similar inertial properties, were tested by 33 golfers representing a range of abilities. Shaft deflection data as well as grip and clubhead kinematics were collected from 14 swings, with each shaft, for each golfer using an optical motion capture system.

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The purpose of this study was to compare the kinetics, kinematics, and muscle activation patterns of the countermovement jump, the power clean, and the jump squat with the expectation of gaining a better understanding of the mechanism of transfer from the power clean to the vertical jump. Ground reaction forces, electromyography, and joint angle data were collected from 20 trained participants while they performed the three movements. Relative to the power clean, the kinematics of the jump squat were more similar to those of the countermovement jump.

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Previous research indicates that the motion of the golf club is not planar and that the plane traced out by the club is different than that of the golfer's hands. The aim of the present study was to investigate how the position of the club, relative to the golfer's swing plane, influences the motion of the club by using a four-segment (torso, upper arm, forearm, and club), three-dimensional forward dynamics model. A genetic algorithm optimized the coordination of the model's four muscular torque generators to produce the best golf swings possible under six different conditions.

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The purpose was to evaluate the traditional method, of visually focusing on the ball, in comparison to focusing on the hole, during the putting stroke. The study design consisted of a pretest, a 4-week practice period, and a posttest. Participants (n = 31, handicap: 18.

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Objective: To use dual-energy x-ray absorptiometry (DXA) to measure the effects of a 16-week community-based swim training program on percent body fat in children and adolescents with intellectual disability (ID).

Design: Convenience sample.

Setting: University sport complex and exercise science laboratory.

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The purpose of this study was to determine the validity and reliability of a new method for measuring three-dimensional (3D) putting stroke kinematics using the TOMI device. A putting robot and a high-speed camera were used to simultaneously collect data for the validity evaluation. The TOMI device, when used in conjunction with standard 3D coordinate data processing techniques, was found to be a valid and reliable method for measuring face angle, stroke path, putter speed, and impact spot at the moment of ball contact.

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The purpose was to assess a novel form of strength training, antagonist resisted training (ART), with potential use in microgravity and athletic rehabilitation settings. ART uses the force from antagonist muscles, during cocontractions, as the source of resistance for the agonists. Strength and electromyography (EMG) measurements were recorded before and after a 6-week training program during which participants trained the left arm while the right arm served as a control.

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This study evaluated the validity of the plumb-bob method as used to determine the break of a putt. Two separate experiments were conducted to examine the consequence of violating inherent assumptions in the method. In the first experiment, a controlled putting environment was constructed to assess the plumb-bob method in determining the break of a putt, if the slope of the green was not constant from the position of the golfer behind the ball through to the hole.

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