Koji Murofushi

Tokyo Medical and Dental University | TMDU · Sports Science Organization

Background: The KOJI AWARENESS� screening test is a self-administered screening tool for assessment of mobility, stability, and strength. It provides corrective exercises corresponding to the individual's answers to the KOJI AWARENESS� test questions. However, there is no evidence of the effectiveness of corrective exercises in improving KOJI AWAR...

Objective This study aimed to validate the KOJI AWARENESS™, a self-screening movement test, and compare it with the Functional Movement Screen (FMS). Methods Fifty-seven healthy participants completed the KOJI AWARENESS™ and functional movement screening. Pearson’s correlation coefficients were used to assess the validity of the test. Subsequently...

Background : Various musculoskeletal screening and functional performance tests are used to evaluate physical condition. However, validated analysis tools that can identify gaps in pain knowledge during athletes’ daily training are lacking. This study aimed to investigate the relationship between pain intensity in athletes during their daily traini...

Perturbation exercises enhance lower limb and trunk muscles, and adding swing perturbation while loading during exercise might improve muscle activation or strength. This study aimed to check variations in trunk and lower limb muscle activity during conventional isometric squats, and whether it will change with or without swing using the Hammerobic...

BACKGROUND: Trunk muscle activity during isometric exercise is altered by external-focus instruction. OBJECTIVE: To check alterations in trunk muscle activity during side plank exercise both with and without instructions to refrain from crushing an item (external-focus instruction method). METHODS: Twenty-one healthy men aged 20–49 participated in...

BACKGROUND: External focus isometric exercises using a paper balloon can change trunk muscle activation in the chest squeeze; however, it is unknown whether this method affects muscle activities in conventional exercises. OBJECTIVE: To check variations of trunk muscle activity during front plank (static task) and shoulder press (dynamic task) both...

BACKGROUND: Muscle activation during isometric contraction can be changed using an external-focus instruction method. OBJECTIVE: To explore and compare the activity of eight upper limb and trunk muscles during isometric chest squeeze exercises, performed in the same posture with and without the exertion of control to avoid crushing an object. METHO...

TRAINING FOR THE HAMMER THROW HAS TRADITIONALLY BEEN SEPARATED INTO 2 PARTS. THE PRIMARY TRAINING METHOD IS THROWING OF THE HAMMER, WHEREAS THE SECONDARY/SUPPLEMENTARY METHOD INVOLVES VARIOUS STRENGTH AND CONDITIONING EXERCISES TO IMPROVE THE ATHLETE'S FITNESS LEVELS FOR THROWING PERFORMANCE. THE IMPLEMENTATION OF SPECIAL STABILITY EXERCISES IN THE...

The motions of a hammer are commonly regarded as a circular movement which a hammer undergoes around a turning human body. During each turn the hammer rises up toward the high point of the trajectory and passes through the low point. Our interest in this study was to understand the energy transfer mechanism through whole body into the hammer. To el...

An increase or decrease of the hammer head mechanical energy was caused by an accumulation of the positive or negative handle power which was the product of wire tensile force and handle velocity in the wire length direction. During single support phase a decrease of the wire tensile force was reduced by a fictitious force caused by handle relative...

The mechanism of hammer head acceleration was understood by a simulation based on a parametric excitation of its handle movement. It was also important for this simulation to adjust initial conditions of differential equations at the start of first turn after preliminary winds. Head speed fluctuation per turn was basically determined by a principle...

The motions of a hammer are commonly regarded as a circular movement which a hammer undergoes around a turning human body. The distance of a throw depends on the speed of the hammer and the angle of its trajectory at the instant of release. The speed of the hammer increases gradually during preliminary winds and turns. During each turn the hammer r...

Motions of the hammer were analyzed to understand the mechanism of acceleration with a hula-hoop model using an energy pumping mechanism. The condition that makes the time derivative of the energy positive is derived as energy pumping for hammer. The condition is expressed in terms of the tugging force times velocity to pump the hammer energy. In t...

The motions of hammer were analyzed to understand the mechanism of acceleration using variable-length pendulum and hula-hoop model using energy pumping mechanism. The condition that makes the time derivative of the energy positive is derived as energy pumping for hammer. The condition is expressed in terms of tugging force times velocity to pump ha...

Dynamics-based force sensor using accelerometers which measures forces and joint torques has been developed. In this study we have applied this method to hammer throw training aid integrating small sensors, signal processing, short-range wireless transmission, wearable data-logger and biofeedback training system. The purpose of this study was to es...

Dynamics-based force sensor using accelerometers which measures forces and joint torques has been developed. In this study we have applied this method to hammer throw training aid integrating small sensors, signal processing, short-range wireless transmission, data-logger and biofeedback training system. The purpose of this study was to establish m...

Dynamics-based force sensor using accelerometers which measures forces and joint torques has been developed. In this study we have applied this method to hammer throw training aid integrating small sensors, signal processing, short-range wireless transmission, wearable data-logger and biofeedback training system. The purpose of this study was to es...

We propose a motion capturing method for 3D real time analysis of athlete performance. This system uses the monocular camera with large spherical aberration of lens to measure 3D positions of point light sources attached on an object in real time without any special lighting. We investigate shortly the principle of Firefly Capturing Method first an...

Ground reaction force and wire tensile force were measured during test throws by three hammer throwers: the Asian record holder, who had a personal best of 83.47 m at the time of the investigation, and two university athletes, with personal bests of 59.95 m and 46.30 m respectively. They were filmed using three high-speed video cameras (250Hz). The...