A STUDY OF BALANCE CONTROL BY FREQUENCY ANALYSIS IN COM AND COP DURING SUSTAINED HAND STAND MOVEMENT

INTRODUCTION: As one of the research on the balance control of hand stand, frequency analysis on center of mass (COM) during hand stand indicated the greatest power spectrum existed below 1Hz (Clement and Rezette, 1985). This study focused on the balance control by means of frequency analysis in COM as well as center of pressure (COP) fluctuations in the A-P direction during 10s sustained hand stand movement

Kinematic analysis of punt kick in football goalkeepers based on the level of kick effort

In the present study, we aimed to investigate the differences in punt kicks by football goalkeepers based on the level of effort required. Twelve experienced goalkeepers participated in the study. The participants were instructed to kick the ball as far as possible in the maximum distance trial (100% trial) and to have a more controlled approach for the 80% and 60% trials. Each punt kick was divided into three events: release of the ball from the left hand (BR), pivot foot ground-contact (LFC), and ball impact (IMP). Right lower limb joint velocity, right hip and knee joint angles, flight distance, ball velocity, and kick angle were calculated. The 80% and 100% trials yielded almost the same velocity for each part of the right leg; however, in the 60% trial, the level of kicking effort was managed by adjusting the velocity of the right ankle joint, starting from BR, in addition to adjustment of the velocity of the right knee joint at LFC. Compared to punt kicks with a lower level of effort, the punt kicks with a higher level of effort involved an increase in the hip joint extension angle for the right leg during the backswing and the lowering of the knee joint angle of the right leg at the start of the forward swing, thus producing forward swing velocity for the right foot

THE STANDARD MOTION MODEL OF A BASKETBALL SET SHOT FOR TEACHING

The purpose of this study was to create a standard motion model of a basketball set shot. Twenty-one male collegiate basketball players participated in three-dimensional data collection session (Vicon MX+, 250Hz), and the method proposed by Ae, et al. (2007) was used to create a standard motion model. The set shot motion in the standard motion model started with the shoulder flexion and hip extension in the downward phase, followed by the sequential motions of the knee, ankle, shoulder, elbow and wrist joints in the upward phase. Immediately before the ball release, the elbow and wrist joints were abruptly extended. The motion variation in the wrist, elbow and shoulder joints just before the ball release were small, implying there must be some commonality in these joint motions

SEX DIFFERENCES IN RACE PROFILE AND STROKE VARIABLES DURING 200-M SPRINT IN JUNIOR KAYAKERS

The purpose of present study was to examine sex differences in race profile and stroke variables during 200-m sprint in junior kayakers. 200-m race time of the male kayakers showed 11% shorter than the female kayakers. In both groups, significant positive correlations were found between kayak velocity and stroke rate. In the three part of duration (Initial: 0-25m, Middle: 100-125m, Finish: 175-Zoom), male kayakers were faster than female kayakers. Kayak velocity of male kayakers significantly decreased in the finish part from the middle part, while the kayak velocity of female kayakers showed a most constant. In conclusion, these different raw profiles might be explained by physiological differences in the upper body power or anaerobic capacities between males and females

GROUND REACTION FORCES DURING THE GOLF SWING USING DIFFERENT GOLF CLUBS IN FEMALE GOLFERS

The purpose of this study was to investigate effects of different golf clubs on the ground reaction forces during the golf swing for females. Ten right-handed female varsity golfers voluntarily participated in this study. Using three different clubs, they hit the ball by their own swing in four conditions (full driver shot, controlled driver shot, 6-iron shot, and approach-wedge shot). Their motion was three-dimensionally captured which was performed with one foot on each force plate. There were no significant differences in the peak resultant forces between the golf clubs, but the peak resultant horizontal force differed between the golf clubs. The female golfers’ resultant reaction force patterns were classified into three patterns, indicating that the golfers generated the reaction forces in their own ways, which would reflect the characteristics of their golf swing

Contributions of phase resetting and interlimb coordination to the adaptive control of hindlimb obstacle avoidance during locomotion in rats: a simulation study.

Obstacle avoidance during locomotion is essential for safe, smooth locomotion. Physiological studies regarding muscle synergy have shown that the combination of a small number of basic patterns produces the large part of muscle activities during locomotion and the addition of another pattern explains muscle activities for obstacle avoidance. Furthermore, central pattern generators in the spinal cord are thought to manage the timing to produce such basic patterns. In the present study, we investigated sensory-motor coordination for obstacle avoidance by the hindlimbs of the rat using a neuromusculoskeletal model. We constructed the musculoskeletal part of the model based on empirical anatomical data of the rat and the nervous system model based on the aforementioned physiological findings of central pattern generators and muscle synergy. To verify the dynamic simulation by the constructed model, we compared the simulation results with kinematic and electromyographic data measured during actual locomotion in rats. In addition, we incorporated sensory regulation models based on physiological evidence of phase resetting and interlimb coordination and examined their functional roles in stepping over an obstacle during locomotion. Our results show that the phase regulation based on interlimb coordination contributes to stepping over a higher obstacle and that based on phase resetting contributes to quick recovery after stepping over the obstacle. These results suggest the importance of sensory regulation in generating successful obstacle avoidance during locomotion

冠動脈バイパス術患者における術前アスピリン投与中止時期の検討

研究科: 千葉大学大学院医学薬学府学位:千大院医薬博甲第医1081号博士(医学)千葉大

Differences in body composition assessments measured by air displacement plethysmography and magnetic resonance imaging in adult females

J-GLOBAL ID : 202201012804701108J-GLOBAL ID : 202101004237845144Magnetic resonance imaging （MRI） and air displacement plethysmography （ADP） are widely used methods for reliable body composition analysis （BCA）. This study aimed to compare the BCA assessments obtained between MRI and ADP methods in 14 adult females. BCA measurements such as whole-body mass, volume, density, fat mass and %fat mass were analyzed by both MRI and ADP methods. 　The masses, volumes and body densities obtained MRI and ADP method were both absolutely and relatively equaled. However, the %fat masses obtained MRI and ADP method were highly correlated （r＝0.950, p＜0.001）, while significant absolute differences in %fat mass were found between the two methods （p＜0.001）. 　It was suggested that the MRI method equivalently evaluated in mass, volume and body density compared with ADP method. Also, MRI method can be relatively evaluated the fat mass and %fat mass but it overestimated absolute values.1520860078898552704application/pdfdepartmental bulletin pape

Ground reaction forces during the full driver shot of a Japanese male professional golfer : a case study

J-GLOBAL ID : 201801009314123820J-GLOBAL ID : 201801006075322255J-GLOBAL ID : 200901004400734279J-GLOBAL ID : 200901081100961987J-GLOBAL ID : 202101004237845144We examined the characteristics of ground reaction forces (GRFs) during the full driver shot of an individual Japanese male professional golfer. In addition to the Japanese male professional golfer, a male collegiate amateur golfer participated in this study. By comparing the GRFs during the backswing and downswing with two golfers, we found that the professional golfer exhibited a transfer of loading from the rear leg to the front leg during the downswing, resulting production of higher peak vertical GRF in the front leg (1.51 N/BW). This finding may provide valuable insights into the magnitude and timing of force for golfers seeking to increase the distance of driver shots in golf practice.1520860078898546048application/pdfdepartmental bulletin pape

Estimations of body segment parameters in Japanese adult females using MRI methods

This study aimed to estimate of Body segment parameters （BSPs） in Japanese adult females using magnetic resonance imaging （MRI） methods. Whole-body MR date of 14 Japanese adult females were obtained using 1.5-T MRI scanner. Thirteen tissue areas were identified by MR dates using Fiji/ImageJ software. Body composition and Limb composition were calculated by multiplying each area,10-mm slice thickness and identified tissue densities. Fourteen body segments such as head and neck, trunk, upper arm, forearm, hand, thigh, shank and foot were defined according to the anatomical landmarks in MR dates. Segment mases （%body mass; %BW） and center of masses （%segment length; %SL） obtained from MRI were compared with regression modeling from previous studies. 　The results of this study have trended to be smaller in upper arm and forearm than typical values. Females were bigger thigh and shank than males, indicating sex difference affected segment mass. Center of masses （CMs） were affected by the definition of segment lengths. It suggested females accumulated fat mass close to trunk. The CM of trunk in female was lower than previous studies, because upper trunk had lower muscle mass than male. These results suggest to consider the influence of female-specific body segment components