• 대한인간공학회지
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• 제11권2호
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• pp.23-33
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• 1992

The distribution of the pressure between the sole of a feet and a supporting surface can reveal the information about the structure and fonction of the foot and the posural control of the whole body. In particular, the measurement of the vertical contact forces between the plantar surface of the foot and the shoe insole is of great importance to reveal the loading distributio patterns incurred from a particular shoe midsole design. In order to investigate the plantar surface pressure distribution, an insole-type sensor with a piezoelectric material is developed and tested. The present paper describes a new method to completely reduce both the shear force and pyroelectric effects that are normally caused from piezoelectric materials.

• 한국산업보건학회지
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• 제19권1호
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• pp.25-29
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• 2009

The purpose of this study was to investigate the effect of two different lifting posture on the plantar foot pressure, force and COP(center of pressure) trajectory path during object lifting. Fourteen healthy adults who had no musculoskeletal disorders were instructed to lift with two postures(stoop and squat) and two object weights(empty box and 10 kg box). Plantar foot pressures, forces and COP trajectory path were recorded by the F-mat system(Tekscan, Boston, USA) during object lifting with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region and one heel region. Paired t-test was used to compare the outcomes of peak pressure and maximum force with different two lifting postures and two object weights. Plantar peak pressure and maximum force under hallux was significantly greater in squat posture than stoop posture during the two different boxes lifting(p<.05). During the empty box lifting, maximum force under lessor toes was significantly less and plantar peak pressure under second metatarsal region was significantly greater in squat than stoop(p<.05). Maximum force under heel was significantly less in squat than stoop posture during 10kg box lifting(p<.05). Finally, COP trajectory path was significantly greater in squat than stoop(p<.05). These findings confirm that there are significantly change in the structure and function of the foot during the object lifting with different posture. Future studies should focus on the contribution of both structural and functional change to the development of common foot problems in adults.

• 한국운동역학회지
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• 제17권4호
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• pp.191-200
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• 2007

The purpose of this study was to analyze the foot-pressure distribution of trekking boots for assessing their functionality. Subjects participated in this study included 10 university male students who had no injury experience in lower limbs and a normal gait pattern. The size of all subjects was 270mm. Five models of trekking boots, most popular in Korea (A, B, C, D & E company), were selected for the test. Using the PEDAR-X system and PEDAR-X insoles, 5 different walking stages were analyzed for the foot-pressure distribution: (a) straight gait; (b) $45^{\circ}$ turn gait; (c) $25^{\circ}$ uphill gait; and (d) $25^{\circ}$ downhill gait. Results of the foot-pressure distribution and functionality on each stage were as follow; 1. Straight gait - In case of Max ground reaction force, mean plantar pressure and Max plantar pressure, there was not a distinct tendency; however, products manufactured by E and A company showed relatively lower pressure distribution. 2. $45^{\circ}$ turn gait - In Max ground reaction force, mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E and A company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E and A company were superior to those by other companies in terms of functionality. 3. $25^{\circ}$ uphill gait - In Max ground reaction force, mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E and C company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E and C company were superior to those by other companies in terms of functionality. 4. $25^{\circ}$ downhill gait - In Max ground reaction force, Mean plantar pressure and Max plantar pressure, there wasn't a distinct tendency; however, products manufactured by E company showed relatively lower pressure distribution. Results also revealed that the products manufactured by E company were superior to those by other companies in terms of functionality. Overall, five pairs of trekking shoes selected in this study showed the excellent performance in several conditions. The findings above may provide us with the important criteria for choosing trekking boots.

• The Journal of Korean Physical Therapy
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• 제22권1호
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• pp.47-51
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• 2010

Purpose: The purpose of this study was to determine whether there are any differences, with and without a toe spreader (TS), in dynamic foot pressure distribution in children with spastic diplegic cerebral palsy. Methods: Dynamic foot pressure recording using the RSscan system were obtained during walking in 12 participants (male=7, female=5) with and without TS. Mean force was measured for four different plantar regions; great toe, forefoot, midfoot, hindfoot. Displacement of center of pressure (COP), velocity of COP displacement and stance time were also measured during gait. Results: TS walking exhibited statistically significant decrease of mean force under great toe and forefoot (p<0.05), compared with a barefoot walking. Also, TS walking exhibited statistically significant increase of antero-posterior displacement of COP (p>0.05). Conclusion: These findings indicate the potential clinical utility of toe spreader to correct dynamic foot pressure during stance phase in children with spastic diplegic cerebral palsy.

• 한국운동역학회지
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• 제15권3호
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• pp.31-49
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• 2005

The purpose of this study was to analyze the weight transfer patterns under the different golf swing types which are full swing control swing and putting stroke. Two women golfers participated in this study, one(165cm, 94.3kg)being classified as a low-handicap(LH)player, the other(165cm, 54.5kg) being classified as a high-handicap(HH) player. Both players are right-handed. Two force plates(Kistler, 9286AA) were synchronized with a motion capture system(Qualisys ProReflex MCU240). Anteriorposterior, mediolateral, and vertical forces were used as an indicator of the pattern of swing. Four discrete positions which are address, top of backswing impact, and finish were identified as an event and three phases which are backswing downswing, and follow-through between he events were also identified. The results showed that, at impact, the total force was 1.24BW ring the full swing 1.17BW during the control stroke, 1.00BW during the putting stroke. Depending on the golf swing types, the differences are existed. At impact, the distribution of forces is different with a low-handicap(LH) player and a high-handicap(HH) player. A LH player has 26% in right foot and 74% in left foot during the full swing 49% in right foot and 51% in left foot during the control swing 49% in right foot and 51% in left foot during the putting stroke. A HH, on the other hand, has 74% in right foot and 26% in left foot during the full swing 62% in right foot and 38% in left foot during the control swing 54% in right foot and 46% in left foot during the putting stroke. From address to top of backswing the amount of vertical forces are changed 43:57(right foot: left foot) to 76:24 during the full swing 47:53(right foot: left foot) to 75:25 during the control swing 50:50(right foot: left foot) to 54:46 during the putting stroke. The biggest weight transfer pattern took place in full swing and the control swing is next, and the putting stroke is the final.

• 전기학회논문지
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• 제58권3호
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• pp.614-620
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• 2009

The force distribution in multi-legged robots is a constrained, optimization problem. The solution to the problem is the set points of the leg contact forces for a particular system task. In this paper, an efficient and general formulation of the force distribution problem is developed using linear programming. The considered walking robot is a quadruped robot with a locked-joint failure, i.e., a joint of the failed leg is locked at a known place. For overcoming the drawback of marginal stability in fault-tolerant gaits, we define safety margin on friction constraints as the objective function to be maximized. Dynamic features of locked-joint failure are represented by equality and inequality constraints of linear programming. Unlike the former study, our result can be applied to various forms of walking such as crab and turning gaits. Simulation results show the validity of the proposed scheme.

• Journal of Mechanical Science and Technology
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• 제14권2호
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• pp.131-140
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• 2000

For a walking robot with high constant body speed, the dynamic effects of the legs on the transfer phase are dominant compared with other factors. This paper presents a new force distribution algorithm to maximize walkable terrain without slipping considering the dynamic effects of the legs on the transfer phase. Maximizing the walkable terrain means having the capability of walking on more slippery ground under the same constraint, namely constant body speed. A simple force distribution algorithm applied to the proposed walking model with a pantograph leg shows an improvement in the capability of preventing foot-slippage compared with one using a pseudo-inverse method.

• 한국정밀공학회지
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• 제21권1호
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• pp.197-204
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• 2004

In this study we presented kinematic and kinetic data of foot joints using approximated equations and partial plantar pressure during gait. The maximum angular displacements of each tarsometatarsal joint were found to range from 4$^{\circ}$to 7$^{\circ}$ and the maximum moments were from 200Nㆍcm to 1500Nㆍcm. It was relatively wide distribution. Foot kinematic data calculated from the approximated equations, which were represented by the correlation between moment and angular displacement, and the data from motion analysis were similar. We found that the movements of foot joint were mainly decided by the passive characteristics of the joint when ground reaction force acts. The method of kinematic and kinetic analysis using approximated equations which is presented in this study is considered useful to describe the movements of foot joints in gait simulations.

• 대한인간공학회지
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• 제25권4호
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• pp.115-119
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• 2006

To investigate the effects of independent suspension technology(IST) of hiking boot on the stability and load of foot, eight participants performed medial and lateral drop landing from 33.4cm height and 85cm distance to uneven surface while wearing normal & IST hiking boots. For the stability of foot during the drop landing, the balance angle & suspension angle and rearfoot angle was analyzed using high-speed video analysis. Also kinetic analysis using the force plate and insole pressure measurement was conducted to analyze vertical & breaking ground reaction force and pressure distribution. Not only the balance angle & suspension angle but also rearfoot angle was improved with IST boots for lateral drop landing. These results indicate the IST boots may have the suspension function which keeps the foot to be stable during landing. However the IST boots did not show any effect for medial landing. This might be related to the hardness of medial part of outsole. Therefore the softer outsole of medial part could be recommended. Furthermore the impact force & breaking force and insole pressure were reduced with IST boot. These results means that IST boot has not only cushioning effect but also good grip effect. Therefore the hiking boots applied the independent suspension function may help to reduce fatigue and prevent injury such as ankle sprain in hiking on uneven surface.

• 한국운동역학회지
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• 제15권2호
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• pp.185-196
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance and it is very important to know the patterns of plantar pressure distribution for the better understanding of forehand stroke. Therefore, the purpose of this study was to investigate the change of plantar pressure distribution according to close, square and open stance patterns during forehand stroke in tennis. Three high school tennis players were recruited for the study and required to perform forehand stroke five consecutive trials in the condition of open, square and close stance. The forehand strokes were filmed with two digital video cameras and measured with pedar system for plantar pressure. The plantar regions under the foot were divided into 3 regions, which were forefoot, midfoot, and rear foot.. In conclusion, the first hypothesis, "The plantar pressure of close stance during forehand stroke would be distributed more largely to the left foot.", was rejected and the result showed that The plantar pressure of close stance during forehand stroke was distributed transferring from right foot to left foot similar to square stance. The second hypothesis, "The plantar pressure of square stance during forehand stroke would be distributed transferring from right foot to left foot." was accepted. The third hypothesis, "The plantar pressure of open stance during forehand stroke would be distributed more largely to the right foot.", was accepted.