The relationship between ground reaction force components and peak power according to induced fatigue during 16-km walking.

The previous reviewed studies on inducement of fatigue through long-time walking were not only very confined, but also not cleared on relationship among variables of fatigue inducement active force, decay rate, and power. This study analyzed relationship between power and component of ground reaction force after fatigue being induced through 16-km walking. The fatigue of adult males and females (n=16) was induced through 16-km walking. Then power, measured for pre and post of fatigue inducement, was evaluated by maximal vertical jump on ground reaction force plate. Variables of vertical jump heights, active force, power, and decay rate showed decreased tendency after fatigue inducement, which followed significant difference (P<0.05) and also positive correlation of r=0.628 (R 2=39%) of between vertical jump heights and power and r=0.589 (R 2=34%) of between active force and decay rate respectively. That is, long-time walking for pursuing of exercise rehabilitation, health promotion and leisure activity has been preferred. In the view of this, this study suggested the necessity to understand the relation between fatigue and power to prevent a potential possibility of injury during long-time walking.

Effect of muscle mass asymmetric between upper and lower limbs on the postural stability and shock attenuation during landing.

The aim of the study was to analyze the effect of muscle mass asymmetric between upper and lower limbs on postural stability and shock attenuation during landing. Twenty adults (without lower limb disorders and who could land from a 35-cm height) participated in this study (mean age, 21.85±2.97 years; mean height, 1.68±0.10 m; mean weight: 68.64±17.36 kg). Subjects performed one-leg landing from 36-cm vertical heights. Ground reaction force components and medial-lateral, anterior-posterior, vertical and dynamic postural stability index were obtained from force platform recordings. We found that muscle mass in right limbs more increased than that of left limbs. Medial-lateral force, vertical force, vertical stability index, and dynamic postural stability index in left leg showed higher value than that of right leg during landing. The asymmetry of muscle mass (%) and ground reaction force variables showed a similar correlation, including dynamic postural stability index (r=0.316). These findings allow us to conclude that the factor of muscle mass asymmetric is a contributor to impulse control and dynamic postural stability index asymmetry. Therefore, knowledge of bilateral limbs asymmetry may provide insights into exercise rehabilitation and performance.

Does maintain consistency with a high quality of cardiac compression force between diastole and systole phase?

The aim of the study was to analyze the cardiac compression force using the vertical force with normalized (100%) in cardiopulmonary resuscitation. Nineteen subjects with basic life support license and instructor career participated in this study. Cardiac compression was performed in a situation positioned practical manikin on ground reaction force and with 1,000 Hz of sample rate. Cardiac compression force in vertical direction showed significant difference among 30 times cardiac compression. Vertical cardiac compression force (N) showed significant difference according to the 30 times of cardiac compression in each diastole (45.79 N) and systole (714.38 N) phase. Also, normalized vertical force showed significant difference according to the 30 times cardiac compression in each diastole (6.80%) and systole (93.20%) phase. This suggests that there is a greater difficulty in performing diastole forces close to 0% than performing a sufficient maximal cardiac compression force in cardiopulmonary resuscitation.

Kinetic analysis of cardiac compression-force according to the level of information provision in the cardiopulmonary resuscitation.

The study was undertaken to investigate the change of cardiac compression force relative to levels of information provision using components of ground reaction force. Male participants of 20s-30s (n=10) who was not trained on cardiopulmonary resuscitation (CPR) and used an automated external defibrillator carried out CPR using manikin on ground reaction force plate. All executed 30 times the CPR according to the levels (1-time viewing, repeated viewing, and basic life support education) of information provision and then total sample of 300 times of ground reaction force data was utilized for the analysis. Rather basic life support condition than 1-time viewing and repeated viewing in velocity of CPR showed better pattern, and executed within 15.09 sec of total elapsed time. Also rather basic life support condition than 1-time viewing and repeated viewing in vertical compression force during release phase showed better relax-ability. Rather basic life support condition than 1-time viewing and repeated viewing in ground reaction force of anterior-posterior direction during contraction phase was insignificant, and reduced compression force toward the oblique direction. Therefore CPR training should be provided as part of cardiac and exercise rehabilitation programs in range of limited scope. It is necessary to include not only definite information but also a practice course of CPR to enhance the survival rate of the cardiac arrested regardless of progressive and scientific growth of CPR fields.

Effect of slipper wearing and carrying positions of infant on dynamic stability and kinetic variable during level walking.

Recently though various hip seats for carrying infant of women was designed and developed, then, wearing slipper may restrain the movement of bare foot. The study was undertaken to investigate the dynamic stability and kinetic variables according to between position of carrying infant and wearing slipper. Adult female (n=10) and under one year age of infant (n=10) participated in the study. Extrapolated center of mass, center of pressure, ground reaction force (GRF), and leg stiffness of gait characteristics using 3-dimensional cinematography and GRF were analyzed. Dynamic stability according to position of carrying infant and wearing slipper was not significant. While when carried an infant against normal gait showed significant difference in breaking force, leg stiffness and loading rate (P<0.001). Of which breaking force and vertical impulse were more increased when the back-carried against fore-carried of trunk. Thus it resulted in transformation on types of impulse transfer to leg and COG of women's carrying infant, which may be strategy for securing a dynamic stability. Therefore experts related with exercise rehabilitation should understand sufficiently on gait characteristics of women with diseases on muscular-skeletal system and perform effective rehabilitation and treatment.

Effect of knee positions on cardiac compression variables in cardiopulmonary resuscitation of rescuer; Manikin study.

The aim of the study was to analyze the effect of knee positions on cardiac compression variables in cardiopulmonary resuscitation (CPR) using the manikin. Adult with career of CPR instructor (n=9; mean age, 27.11±6.60 years; mean heights, 177.39±4.40 cm; mean weights, 69.45±14.85 kg) participated in the experiment, and each participant performed cardiac compression from two different knee positions. Cardiac compression was 30 times per minute for each position with order of position randomized. The results obtained from variables of cardiac compression force were composed of compression velocity, elapsed time, decay rate, and loading rate in maximum and minimum medial-lateral, anterior-posterior (AP), vertical direction respectively. The above variables in 20.3 cm of knee position showed effective result than that of 50 cm of knee position, while maximum AP compression force increased. Given the often predictable setting of sports and exercise rehabilitation related with cardiac arrest, CPR relative to change of knee position were significantly associated with more efficient cardiac compression variables. These data have significant implications for health services program in fields of sports and exercise rehabilitation.

The contribution analysis of knee compression bandage and arm swing control on maximum horizontal distance in standing long jump.

The aim of the study was to analyze the effect of knee compression bandage and arm swing control on the maximum horizontal distance and ground reaction force variables in standing long jump. Adult male (n=8; mean age, 22.75±1.98 years; mean heights, 1.77±0.03 m; mean weights, 71.82±12.87 kg) participated in the experiment. The results obtained from variables of ground reaction force (GRF) in medial lateral, anterior posterior (AP), vertical (V) direction, resultant GRF (RGRF), decay rate (%), and maximum horizontal distance (MHD) were as follows; MHD, AP GRF, VGRF, RGRF (AP-V), and ratio of load reduction (%) showed more effective result under both wearing of knee compression bandage and arm swing. In analysis of main effects, MHD, AP GRF, VGRF, and RGRF showed more increased value in case of wearing of knee compression bandage than as was not. While arm swing during standing long jump (SLJ) works as important factor to MHD, showed more effective factor in exercise rehabilitation, injury prevention and swell treatment etc. in wearing of worn knee compression bandage. Therefore it was assumed that arm swing and wearing of knee compression bandage may improve the performance of SLJ. Also, the characteristics of knee compression bandage suggest that it can be a great help for those participating in exercise rehabilitation.

Kinetic analysis of downward step posture according to the foothold heights and visual information blockage in cargo truck.

The study was undertaken to compare and analyze kinetic variables during downward foot-on according to the foothold heights under interrupted-visual information on 25-t cargo truck. Skilled adult male drivers (n=10) engaged in cargo truck driving over 1 year participated in the experiment. The results obtained from cinematographic and ground reaction force data during downward foot-on as follows; First, leg stiffness, peak vertical force (PVF) and loading rate showed significant difference as an increase of foothold heights, that is, interrupted-visual information showed greater impulse force than as was not. Second, variables of center of pressure (COP) with interrupted-visual information did not showed difference, but anterior-posterior COP and COP area showed an increasing tendency as an increase of foothold heights. Third, dynamic posture stability index (overall, medial-lateral, anterior-posterior, and vertical) showed significant difference as an increase of foothold height, that is, interrupted-visual information showed lower index than as was not. Therefore it will be possible to control successfully the leg stiffness, loading rate, and PVF when preparing an estimate for air phase time and impulse force through habitual cognition and confirmation at landing during downward foot-on from cargo truck. Identifying these potential differences may enable clinicians to assess type of injury and design exercise rehabilitation protocols specific.

Effect of wearing positions of load on the dynamic balance during gait.

The study aim to analyze the influence on dynamic stability relative to positions carrying with weight during gait, for which experiment participated with healthful adult males (n=9), were performed under three-dimensional (3D) conditions of no load (NL), right of trunk (RT), and front of trunk (FT). The kinematic and kinetic conclusions obtained from 3D cinematography and ground reaction force system were as follows; 1-step time elapsed showed longest in NL of all, and maximum velocity of RT showed slower than NL and FT, which resulted in significant level at (P<0.05) respectively. While NL showed slower average velocity than RT and FT, RT showed larger incline angle (extrapolated center of mass θ) than NL and FT, which resulted in significant level at (P<0.01) respectively. Also FT showed larger peak vertical force than NL and RT, which resulted in significant level at (P<0.001). Because gait pattern is regarded it as a success when fulfilled both forward propulsive force and dynamic stability, we may ensure that each other active strategy for securement and performance in a situation carrying with 20 kg of the same weight in forward and lateral plane was mobilized. However, participants in pathological gait such as leg injury, and exercise rehabilitation during walking should avoid carrying loads bag to ensure dynamic stability.

Effect of lower limb kinetic on carrying infant by hip seat carrier during high heel gait.

While common characteristics between wearing of high heel between carrying an infant elevate height of center of gravity, it is not known what interaction effect influence to leg stiffness. The aim of the study is to investigate the effect of carrying infant by hip seat carrier on leg mechanics during high heel gait. Adult female (n=9) and infant (n=9) participated as subjects. Infant was positioned on rear of trunk as of wearing 6 cm of high heel shoe. Change of leg mechanics was analyzed with ground reaction force variables (1st peak vertical force [PVF], 2nd PVF, center of pressure [medial-lateral, anterior-posterior]), extrapolated center of mass (XCoM) theta, and leg stiffness. While carrying infant with wearing of high heel more increased 1st PVF, 2nd PVF, and leg stiffness than normal gait, and more decreased medial-lateral center of pressure and XCoM theta. High heel and carrying infant showed potential transformation of posture for securement of stability, which related with mechanism to decrease an impulse type. In conclusion, it is suggest that gait for long time in the condition may accumulate fatigue on leg and increase falling injury, so experts of clinics and exercise rehabilitation should understand the mechanism that could recommend guideline for exercise prescription on several problems.

Relationship among the variables of kinematic and tilt angle of whole body according to the foot trip during gait.

The aim of this study was to analyze the relation between incline angle of whole body and kinematic variables at tripping during gait. The participants consisted of healthy adult female (n=6). The three-dimensional (3D) motion analysis of posture restoring after inducing tripping of right foot at supporting phase of left foot was performed. As a result, supporting time elapsed of one stride and one foot at tripping showed longer than that of normal gait. The length of one stride showed longer at tripping than that of normal gait, and velocity of center of gravity (COG) showed faster at tripping than that of normal gait. Anteriorposterior incline angle of whole body showed more forwarded incline at tripping than that of normal gait. As a result of correlation among variables, one stride and supporting time elapsed showed positive relation r=0.973 (R2 =0.947, P<0.001), also r=0.920 (R2 =0.846, P<0.001) relative to velocity of COG, r=0.970 (R2 =0.941, P<0.001) of 1-stride time elapsed relative to velocity of COG and r=0.833 (R2 =0.613, P<0.05) of velocity of COG relative to anteriorposterior incline angle respectively. Therefore instantaneous stoppage of gait posture when tripped at supporting phase of one leg during gait may be impossible and rather may cause a recovery of gait pattern when secured the faster velocity of COG and the longer of supporting time elapsed of one leg.

A comparison of ground reaction force components according to the foothold heights in 16-t truck during downward step.

The aim of this study is to compare and analyze the components of ground reaction force (GRF) relative to the foothold heights during downward step of 16-t truck. Adult males (n= 10) jumped downward from each 1st, 2nd, 3rd foothold step and driver's seat orderly using hand rail. Sampling rate of force components of 3 axis (medial-lateral [ML] GRF, anterior-posterior [AP] GRF, peak vertical force [PVF]), variables (COPx, COPy, COP area) of center of pressure (COP), loading rate, and stability index (ML, AP, vertical, and dynamic postural stability index [DPSI]) processed from GRF system was cut off at 1,000 Hz. and variables was processed with repeated one-way analysis of variance. AP GRF, PVF and loading rate showed higher value in case of not used hand rail than that used hand rail in all 1st, 2nd, and 3rd of foothold step. DPSI showed more lowered stability in order of 2nd, 3rd step than 1st foothold step used with hand rail, of which showed lowest stability from driver's seat. COPx, COPy, and COP area showed higher value in case of 2nd and 3rd than that of 1st of foothold step, and showed lowest stability from driver's seat. It is more desirable for cargo truck driver to utilize an available hand rail in order of 3rd, 2nd, and 1st of foothold step than downward stepping directly, thus by which may results in decrease of falling injuries and minimization of impulsive force transferring to muscular-skeletal system.

Effect on the parameters of the high-heel shoe and transfer time of ground reaction force during level walking.

This study aimed to analyze an effect on the parameters of high-heel shoe and transfer time of ground reaction force during level walking and subjects participated were composed of adult female subjects (n=13) of 20s with height of high heel (0 cm, 9 cm, respectively). Instrument used for the study was 1 set force plate (AMTI-OR9-7) and sampling rate for data collection of analysis parameters was set-up at 1,000 Hz. The revelation of required coefficient of friction (RCOF) maximum showed significant difference with more rapid than that of 1st peak vertical force (1 PVF). Transfer time of body weight showed significant difference with more delay at 9 cm than that of 0 cm. RCOF required more frictional force required because PVF showed significant difference with larger value on 9 cm than that of 3 cm at 1 PVF. Both center of pressure (COP) x and COPy showed rather less displacement on 9 cm than that of 0 cm. In addition, level walking by high heel shoe did not control efficiently the ground reaction force due to restricted control capacity of coefficient of frictional force and therefore could suggest an inducement of muscle fatigue, heightening a possibility of sliding and falling due to decrease of frictional force.

Effect of the kinetic variables and postural stability between bilateral in lower limbs by the Oreum trekking exercise: asymmetric index.

This study aimed to analyze an effect of the kinetic variables and postural stability between bilateral in lower limbs by participation of Oreum trekking exercise program and subjects participated were composed of adult male and female subjects (n=14) of 20s. Experiment was performed with the drop landing which can evaluate postural stability and kinetic variables between bilateral in lower limbs. peak vertical force (PVF) value showed significant difference with the less in case of post than before participation of Oreum trekking exercise. Also PVF of bilateral in lower limbs did not showed significant difference, and too the effect of interaction. vertical stability index (VSI) and dynamic postural stability index (DPSI) showed significant difference with improvement of postural stability by Oreum trekking, but did not between bilateral in the limbs. Particularly the result of one-way analysis of variance due to VSI's effect of interaction, showed the more influence on the improvement of postural stability in left leg after participation of Oreum trekking exercise. When consideration the above, the analysis result on asymmetric index of bilateral in lower limbs showed more symmetric pattern in post than before participation of Oreum trekking exercise program.

Motor ability of forelimb both on- and off-riding during walk and trot cadence of horse.

The aim of this study was to investigate the motor ability of forelimb according to on- or off-riding during cadences (walk and trot) of horse. Horses and rider selected as subject consisted of total 37 heads of Jeju native horse and 1 female rider. The variables analyzed composed of 1 stride length, 1 step length, elapsed time of stance, elapsed time of swing, elapsed time of 1 step, and forward velocity (x-axis). Two-way analysis of variance of variables was employed for the statistical analysis with the level of significance set at 5% (P<0.05). Trot cadence showed significant difference with the faster and shorter during trot than that of walk in velocity and elapsed time. When analyzed interaction effect in stance and swing phase, the locomotion showed the shorter elapsed time in trot than that of walk, but more delayed in case of on-riding during stance phase, whereas the case of on-riding showed with the shorter during swing phase than that of the case of off-riding These result of horse's analysis meant that there was very close relation among variables of rider's weight-velocity-stride length-stride elapsed time. Next study will be necessary to analyze cadence variables added both stride length and rider's weight for riding activity and rehabilitation during horse riding using Jeju native horse.