Published papers

Hard braking of a bicycle often causes ruler over the handlebar . To Analyse this phenomenon, we assumed that bicycle-rider system consist of rigid body model which have one mass and one arm. Input of this system was braking force function which acts as frictional force between tire and road surface . We analyzed this model by computer simulation method. Results of computer simulation well showed experiment tal data. Simulation showed, if rider braked very hard with him over the handlebar, he can avoid danger, as quickly as he could release brake levers, or as far as he couldshift his seated position backward.

In order to collect information concerned with the development of a measuring device for baseball pitching, pattern of motion and ball speed during a baseball pitch were estimated from acceleration measured at the wrist through multivariate analysis. The subjects were 26 college baseball players (eight pitchers, five catchers, nine infielders and four outfielders). Three accelerometers were attached to the wrist of each subject. The subjects then pitched fifteen times, with intensities ranging from weak to full, to a defensive net set up six meters distant. The accelerometers were arranged perpendicularly to each other on three axes : distal-proximal direction, ulnar-radial direction, and dorsalpalmar direction. The ball speed was measured with a laser device set between the subjects and the defensive net. The time of ball-release was detected using electrical conductive tape placed on the tip of each subjects index and middle fingers and the ball. After extracting the 18 parameters relating to amplitude and time that characterize the acceleration wave, the 26 subjects were classified into three groups-A, B and C-by cluster analysis, and ball speed was estimated in each group by multiple regression analysis. The estimation errors were 2.3 ± 1.8% in group A, 2.5 ± 2.3% in group B, 2.4 ± 2.4% in group C, and 3.4 ± 2.8% for all data. For estimating the ball speed, acceleration in the distal-proximal direction was more effective than that in the other two directions.

バスケットボールのフリースロー映像を観察する際の熟練者と非熟練者の眼球運動データから，シュート結果の予測を迅速にかつ効率よく評価するための選択的な視覚探索ストラテジーを示した

中高年を対象とした、ITを活用した生活習慣改善プログラム「インターネット健康コミュニティ」の概要とその効果について述べる。生活習慣改善は、長期に継続して取り組むこと、また本人が主体的に取り組むことが重要である。本プログラムのインターネットでの記録蓄積・コミュニケーションと対面型のコミュニケーションを併用しているという特徴は、食事・運動記録の蓄積によりセルフモニタリングが可能となること、対面でのコミュニケーションが継続的な記録の蓄積の原動力となりえることが示唆された。(著者抄録)

Objectives: The aim of this study was to develop an estimation equation for energy expenditure during water walking based on the acceleration and walking speed. Design: Cross-validation study. Methods: Fifty participants, males (n = 29, age: 27-73) and females (n = 21, age: 33-70) volunteered for this study. Based on their physical condition water walking was conducted at three self-selected walking speeds from a range of: 20, 25, 30, 35 and 40 m/min. Energy expenditure during each trial was calculated. During water walking, an accelerometer was attached to the occipital region and recorded three-dimensional accelerations at 100 Hz. A stopwatch was used for timing the participant's walking speed. The estimation model for energy expenditure included three components; (i) resting metabolic rate, (ii) internal energy expenditure for moving participants' body, and (iii) external energy expenditure due to water drag force. Results: When comparing the measured and estimated energy expenditure with the acceleration data being the third component of the estimation model, high correlation coefficients were found in both male (r = 0.73) and female (r = 0.77) groups. When walking speeds were applied to the third component of the model, higher correlation coefficients were found (r = 0.82 in male and r = 0.88 in female). Good agreements of the developed estimation model were found in both methods, regardless of gender. Conclusions: This study developed a valid estimation model for energy expenditure during water walking by using head acceleration and walking speed. (C) 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

' The authors developed a microcomputer-based data logging device to evaluate the swimming stroke motion. This newly developed device enabled observation of the tri-axial wrist accelerations in swimming over a one hour-period with no-restrictions. In this study, we looked at the change in wrist acceleration affected by swimmer's fatigue during intensive interval training. The direct linear transformation method was used for kinematical quantitative evaluation. A blood lactate test was used as a physical quantitative evaluation of the swimmer's fatigue. It was observed that swimmers' stroke motion changed with increased exhaustion. And these changes were also observed in acceleration patterns.'