• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.17-24
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• 2012

This study is for providing fundamental data of sport biomechanics in GRF & plantar pressure of stepping foot of skilled & unskilled players' at the soccer instep shooting moments. Wearing Pedar-x of Novel, the study has drawn the following conclusion after measuring and analyzing the impact on the GRF and plantar pressure of stepping foot at the instep shooting moments. First, maximum vertical GRF showed higher in the skilled group than in the unskilled group. The results showed significantly different. This study reached the conclusion that the players in the skilled group performed faster and stronger stepping foot motions that the ones in the unskilled(p<.01). Second, since the plantar pressure of the skilled group appeared significantly higher than that of the unskilled, it has brought us to the conclusion that the skilled group performed faster and stronger stepping foot motions than the unskilled group (p<.05). Third, at the moment of instep kicking, the skilled group's average maximum plantar foot pressure of stepping foot was higher than the unskilled. Though the difference was not statistically significant, it can be concluded that the skilled group performed faster and stronger stepping foot motions than the unskilled group(p>.05). Fourth, for the COP moving route of stepping foot while instep kicking, the skilled people performed accurate and strong shooting motions directly toward the target direction with stable postures, no matter how it's left, right, front or back.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.805-814
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• 1997

Injuries to the menisci occur in a variety of ways, most commonly with a twist, pivot, squat, or valgus stress to the knee. Tear patterns are classified to longitudinal, horizontal, or transverse features according to the mechanism of injury. Work-related meniscal tear usually occurs with a repetitive usage of the foot, hence it can be classified as a cumulative traumatic disorder. We found a 47 year-old female worker who had been taking charge of repetitive foot-switch stepping for 8 years. She suffered from pain in the right knee since 5 months ago. Tenderness along the medial joint line of the right knee was observed and pain was aggravated with full flexion of the right knee. On magnetic resonance imaging, high signal intensity was observed at the posterior horn of the medial meniscus of the right knee. Degenerative longitudinal and transverse complex tear in the medial meniscus was observed on arthroscopy. Arthroscopic partial meniscectomy was performed. We surveyed the work process and the health status of co-workers. It turned out that the work process was compatible to injure the meniscus and nine out of fourteen co-worker(64.3%) complained pain of the knee. No other factors related to her meniscal tear could be found except for the situation at her work. Therefore, we conclude that meniscal tear is related to the repetitive stepping of foot switch.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.2
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• pp.100-105
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• 2013

In this study, we analyze the balance of quadruped walking robots. For this purpose, a simplified polygonal model of a quadruped walking configuration is considered. A boundary-range-based balance margin is used for determining the system stability of the polygonal walking configuration considered herein. The balance margin enables the estimation of the walking configuration's balance for effective walking. The usefulness of the balance margin is demonstrated through exemplary simulations. Furthermore, balance compensation by means of foot stepping is addressed.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.67-74
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• 2014

This study researched into the left-right inclination of the rear foot at the lower limb joints, knee joint angle, angular velocity of the knee joint, angular acceleration and the max. Based on the analysis of kinematics according to the changes in the height of step box (6, 8, 10 inches) during step aerobics of female college students majoring in physical education. The findings of this study are as follows: Then angle of the knee joint decreased as the height of the step box increased the min. Angle was measured right before the right foot was on the step box, and the angle tended to decrease as the step box get heightened. The left-right inclination of the rearfoot angle according to the height of step box increased as the height increased. In the 'pull-up' stage during which the weight was loaded on the right foot the angle increased, while in the right foot stepping stage during which the right foot was on the ground, the left-right inclination of the rearfoot angle increased as the height of the step box increased. The angular velocity of the knee joint according to the height of step box started increasing when the right foot initially stepped on the step box and during the initial stepping section, the angular velocity decreased as the height of step box increased. The changes in angular acceleration of the knee joint according to the height of step box increased as the height of step box increased.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.5
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• pp.368-373
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• 2003

This paper presents a cost-effective 3D foot scanner system that provides the 3-dimensional point cloud foot data to design the custom footwear. To measure the 3-dimensional point cloud data of the foot, a CCD camera, a Non-Gaussian laser line projector and optical triangulation method are employed. Furthermore, the integrated system employs a measurement base, a frame grabber, a CCD moving cart, a stepping motor and a computer. The measurement result is saved as 3D dxf format and it could be converted to 2D essential data fer a shoe design. The experimental results demonstrate that the proposed system have the decent resolution of 1mm which is enough for last and shoe design.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1017-1021
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• 2004

In this paper, a cost-effective integrated 3D system for measuring and sizing foot is proposed. The proposed system employs two CCDs and a laser line projector which are capable of accurately measuring foot. The measurement is based upon the biologically motivated stereo vision principle providing ruggedness against minor system distortions. According to the tolerance, calibration between two different views are implicitly applied. Furthermore, the measurement system employs a measurement base, a frame grabber, a CCD moving cart, a stepping motor and computer. Analysis and design procedure is presented for the calculation of the 3D foot data and the proposed system. Experimental results on the proposed system would verify the concept and system operation.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.47-55
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• 2009

In this study, a robot foot having toes for firm stepping on uneven surface is proposed. The toes are connected to the lower leg by parallel links so that the lower leg can rotate in the rolling and pitching directions during stance phase without ankle joint. The landing performance of the foot on uneven surface was evaluated by relative comparison with that of the most common foot making point contact with the walking surface, since the test conditions considering real uneven surface could be hardly defined for its objective evaluation. Anti-slip margin(ASM) was defined in this study to express the slip resistance of a robot foot when it lands on a projection with half circular-, triangular- or rectangular cross section, assuming that uneven surface consists of projections having these kind of cross sections in different sizes. Based on the ASM analysis, the slip conditions for the two feet were experimentally confirmed. The results showed that the slip resistance of the new foot is not only higher than that of the conventional point contact type foot but also less sensitive to the surface friction coefficient.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.207-219
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• 2005

The purpose of this study was to determine the effect of the foot rotation on the lower limb muscles. Fourteen subjects performed step-up/step-down at a cadence of 80 beats/min, exercises with the foot neutral, $35^{\circ}$ internally rotated, and $35^{\circ}$ externally rotated, respectively. For each variable, a one-way analysis of variance (ANOVA) was used to determine whether there were significant differences between genders and among the eight types of jump. When a significant difference was found in jump type, post hoc analyses were performed using the Tukey procedure. A confidence level of p < .05 was used to determine statistical significance. The results showed that significant changes in averaged IEMG values occurred with the internal rotation of the foot in the lateral gastrocnemius during the knee extension, and in the semitendinosus during the knee flexion. During the knee extension, however, the internal rotation of the foot produced a significantly lower Averaged IEMG values than the neutral foot position in the medial gastrocnemius. The results also found that the peak IEMG activity of the rectus femoris during the knee extension for the external rotation of the foot was Significantly higher than the corresponding values in the neutral position of the foot, while the intenal rotaion of the foot exhibited a significant difference with the neutral position of the foot in the semitendinosus during the knee flexion. In general, the foot rotation position did not influence the average IEMG and Peak IEMG values of most muscles. The practice of adopting foot rotation to selectively strengthen individual muscles of the lower limb was not supported by this study. The external rotation of the foot produced high muscle activities in the quadriceps during the knee extension. For the knee extension, therefore, maintaining a laterally rotated position should be need for stable and comfortable position.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.57-65
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• 2010

Korean traditional martial arts Taekkyon has a unique stepping method, Poombalbki. The purpose of this study was to investigate kinematic factors and ground reaction forces on two types of Poombalbki, one of which use knee bending and the other use chiefly hip bending. Six male taekkyoners who are the students of Y University participated in this study. Positions and velocities of CoM, the elapsed times of each phase, angles and angular velocities of low limb joints, and GRFs were analyzed for this study. The results were as follows; CoMs of whole body, trunk, and head were more posteriorly positioned in performing hip bending Poombalbki than knee bending one. Horizontal velocities of those were slower in performing hip bending Poombalbki. A player stayed more shortly within range of his opponent in performing hip bending Poombalbki. The vertical and horizontal components of GRF of forward-stepping foot were smaller in performing hip bending Poombalbki(p<.05). In conclusion hip bending is useful strategy, because A player is farther from his opponent, he stayed more shortly within range of his opponent, and the smaller weight is loaded on his front foot in performing hip bending Poombalbki than knee bending one.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.11-17
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• 2008

Falls associated with tripping over an obstacle can be dangerous, yet little is known about the strategies used for stepping over obstacles by Parkinson's patients. The purpose of this study was to investigate stepping over gait characteristics according to obstacle height in Parkinson's patients. The gait of 7 Parkinson's patients was examined during a 5.0 m approach to, and while stepping over, obstacles of 0, 2.5, 5.2, and 15.2 cm. Only five Parkinson's patients were able to clear all obstacles successfully; as such, only their data were analyzed. A one-way ANOVA for repeated measures was employed for selected kinematic variables to analyze the differences of the height of four obstacles. The results showed significant differences between obstacle height and: approaching speed (AS), foot clearance from the obstacle(FC), and step width (SW). The results showed no significant differences between obstacle height and: crossing speed (CS), toe distance (TD), and heel distance (HD). This strategy tends to reduce the risk of toe contact with the obstacle. Parkinson's patients were stepping over the obstacle slowly, stably and inefficiently.