• Interaction and multiscale mechanics
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• v.5 no.1
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• pp.75-90
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• 2012

This paper investigates the effects of sports ground materials on the transfer characteristics of the landing impact force using a coupled foot-shoe-ground interaction model. The impact force resulting from the collision between the sports shoe and the ground is partially dissipated, but the remaining portion transfers to the human body via the lower extremity. However, since the landing impact force is strongly influenced by the sports ground material we consider four different sports grounds, asphalt, urethane, clay and wood. We use a fully coupled 3-D foot-shoe-ground interaction model and we construct the multi-layered composite ground models. Through the numerical simulation, the landing impact characteristics such as the ground reaction force (GRF), the acceleration transfer and the frequency response characteristics are investigated for four different sports grounds. It was found that the risk of injury, associated with the landing impact, was reduced as the ground material changes from asphalt to wood, from the fact that both the peak vertical acceleration and the central frequency monotonically decrease from asphalt to wood. As well, it was found that most of the impact acceleration and frequency was dissipated at the heel, then not much changed from the ankle to the knee.

• Archives of Reconstructive Microsurgery
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• v.10 no.1
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• pp.34-37
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• 2001

The injury on the dorsum of foot is usually manifested in the defect of bone and soft tissue, so its reconstruction requires composite tissue. Free flap satisfies this defect but its indication is determined by the defect size, recipient status and so on. Iliac crest bone and fibular bone are useful bone flap but in more than 8cm defect, fibular flap is more useful. The drawback of fibular free flap is the absence of soft-tissue coverage, so another local flap and myocutaneous flap must be added. Fibula-hemisoleus ostemusculocutaneous free flap has been used for the reconstruction of upper and lower extremity. Its advantages are one stage operation, one donor site and the flexibility of the reconstruction with the use of muscle, bone, and skin. This flap has never been reported for the reconstruction of dorsum of foot. In our case, 20-year-old woman was referred with the 17 cm defect of 1st metatarsal bone and $16{\times}8cm$ sized soft tissue loss on the dorsum of the right foot. We reconstructed successfully the dorsum of foot with fibula-hemisoleus osteomusculocutaneous free flap and the patient can walk without crutches after 6 monthes.

• Physical Therapy Korea
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• v.6 no.1
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• pp.15-22
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• 1999

The Posterior Leaf Spring (PLS) has been used for hemiplegic patients in order to help their walking and to increase their balance function. Past studies have mainly focused on the PLS's influence on patients' walking without taking balance function into consideration. The purpose of this study was to identify the immediate effect of PLS on the standing balance in hemiplegic patients. Fifteen hemiplegic patients participated in this study: 10 men and 5 women, with an average age of 53.8 years. Standing balance was measured using a computerized dynamic posturography device under three conditions namely bare-foot standing, standing in shoes without PLS, and standing in shoes with PLS. The results were as follows: 1) The composite equilibrium scores of patients who stood in shoes only and stood in shoes with PLS were higher than those of patients who stood bare-foot. 2) There were no statistical difference in the composite equilibrium scores between the standing condition of patients who stood bare foot and that of patients who stood in shoes with PLS. In conclusion, it is not clear whether or not the PLS affects the standing balance of hemiplegic patients. Further study is required to determine the precise effect of the PLS on standing balance in hemiplegic patients who are not wearing shoes. This is particularly relevant in Korea culture where custom demands the removal of shoes when entering any house or even many restaurants.

• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.606-615
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• 2023

The purpose of this study was to investigate the effect of increasing weight load on the dynamic balance on Y-balance Test(YBT). 18 male and female adults in their 20-30s (age: 23.17±1.72 years, height: 172.46±9.84 cm, weight: 73.39±11.44 kg, leg length: 88.89±5.69 cm) participated in the experiment. To measure the dynamic balance, the YBT was used to measure the reach distance, composite score, and COP variables to derive the results. As a result of the study, dynamic balance was improved in weight load in posteromedial and posterolateral reach and overall score during YBT. As a result of COP, anteroposterior amplitude, left and right COP velocity, and COP area during anterior reach improved dynamic balance in weight load in the right foot, but there was no difference during the posteromedial reach, ML amplitude in the left foot, AP COP velocity in left foot, ML COP velocity and COP velocity in both foot, and COP area in both foot improved dynamic balance when weight load during posterolateral reach.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.977-987
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• 2023

The purpose of this study was to investigate the effect of visual information on the dynamic balance on Y-balance Test(YBT). The subjects of the study were 18 male and female adults in their 20s and 30s (age: 23.17±1.72 years, height: 172.46±9.84 cm, weight: 73.39±11.44 kg, leg length: 88.89±5.69 cm) who participated in the study. To measure dynamic balance between binocular and monocular use, absolute reach distance, composite score, and COP variables were measured on left and right feet through YBT and results were derived. As a result of the study, monocular block(left and right eye block) showed higher absolute reach and composite scores than binocular use in posterolateral, posteromedial, and composite scores during YBT. As a result of COP, there was no difference in anterior and posteromedial reach. When reaching posterolateral, AP COP velocity of left foot in monocular block appeared slower than that in binocular vision, and in COP velocity, COP velocity of left foot in monocular block appeared slower than binocular vision.

• Archives of Reconstructive Microsurgery
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• v.8 no.1
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• pp.77-83
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• 1999

The skin on the dorsum of the foot is a source of the reliable thin and sensory cutaneous free tissue transplantation with or without tendon, bone and joint. A composite flap with attached vascularized tendon grafts for the combined loss of skin and tendon on the dorsum of the hand and foot offers an immediate one stage solution to this problem. The flap provides a very durable innervated tissue cover for the heel of the foot and the dorsum of the hand and an osteocutaneous transfer combined with the second metatarsal. The major dorsalis pedis artery is constant in size, but the first dorsal metatarsal artery is variable in size and location. The dorsal surface of the foot receives sensory innervation through the superficial peroneal nerve and the first web through the deep peroneal nerve. Authors had performed 5 dorsalis pedis free flap transplantation in the foot and hand at Department of Orthopedic Surgery, Chonbuk National University Hospital from August 1993 through August 1997 and followed up for the period of between 19 and 67 months until March 1999. The results were as follows 1. 5 cases dorsalis pedis free flap transfer to the foot(4 cases) and the hand(1 case) were performed and the recipient was foot dorsum and heel 2 cases each and hand dorsum 1 case. 2 All of 5 cases(100%) were survived from free flap transfer and recipient artery was dorsalis pedis artery(2 cases), anterior tibial artery(1 case), posterior tibial artery(1 case) and ulnar artery(1 case) and recipient veins were 2 in number except in the hand. 3. Long term follow up of the exterior and maceration was good and sensory recovery was poor 4. Donor site was covered with full thickness skin graft obtained from one or both inguinal areas at postoperative 3rd week and skin graft was taken good and no morbidity was showed.

• Archives of Plastic Surgery
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• v.35 no.6
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• pp.716-722
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• 2008

Purpose: Split or full thickness skin graft is generally used to reconstruct the palmar skin and soft tissue defect after release of burn scar flexion contracture of hand. As a way to overcome and improve aesthetic and functional problems, the authors used the preserved superficial fat skin(PSFS) composite graft for correction of burn scar contracture of hand. Methods: From December of 2001 to July of 2007, thirty patients with burn scar contracture of hand were corrected. The palmar skin and soft tissue defect after release of burn scar contracture was reconstructed with the PSFS composite graft harvested from medial foot or below lateral and medial malleolus, with a preserved superficial fat layer. To promote take of the PSFS composite graft, a foam and polyurethane film dressing was used to maintain the moisture environment and Kirschner wire was inserted for immobilization. Before and after the surgery, a range of motion was measured by graduator. Using a chromameter, skin color difference between the PSFS composite graft and surrounding normal skin was measured and compared with full thickness skin graft from groin. Results: In all cases, the PSFS composite graft was well taken without necrosis, although the graft was as big as $330mm^2$(mean $150mm^2$). Contracture of hand was completely corrected without recurrence. The PSFS composite graft showed more correlations and harmonies with surrounding normal skin and less pigmentation than full thickness skin graft. Donor site scar was also obscure. Conclusion: The PSFS composite graft should be considered as a useful option for correction of burn scar flexion contracture of hand.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.1
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• pp.45-56
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• 2010

Polymer composite materials offer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic (GFRP) composites is presented. Fabrication techniques investigated during this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented dining composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results.

• Archives of Plastic Surgery
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• v.41 no.3
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• pp.285-289
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• 2014

The composite anterolateral thigh flap with vascularized fascia lata has emerged as a workhorse at our institution for complex Achilles defects requiring both tendon and soft tissue reconstruction. Safe elevation of this flap, however, is occasionally challenged by absent or inadequate perforators supplying the anterolateral thigh. When discovered intraoperatively, alternative options derived from the same vascular network can be pursued. We present the case of a 74-year-old male who underwent composite Achilles defect reconstruction using a segmental rectus femoris myofascial free flap. Following graduated rehabilitation, postoperatively, the patient resumed full activity and was able to ambulate on his tip-toes. At 1-year follow-up, active total range of motion of the reconstructed ankle exceeded 85% of the unaffected side, and donor site morbidity was negligible. American Orthopaedic Foot and Ankle Society and Short Form-36 scores improved by 78.8% and 28.8%, respectively, compared to preoperative baseline assessments. Based on our findings, we advocate for use of the combined rectus femoris myofascial free flap as a rescue option for reconstructing composite Achilles tendon/posterior leg defects in the setting of inadequate anterolateral thigh perforators. To our knowledge, this is the first report to describe use of this flap for such an indication.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1526-1533
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• 2004

The needs of walking assistant device such as the Ankle Foot Orthosis (A.F.O) are getting greater than before. However, most of the A.F.O are generally imported rather than domestic manufacturing. The major reason of high import reliability is the rack of impact properties of domestic commercial products. Therefore, this research is going to focus on the evaluation of impact properties of the A.F.O which has the high import reliability. Unfortunately, these kinds of researches are not performed sufficiently. This research is going to evaluate impact energy behavior in composite materials such as the glass/epoxy (S-glass, [0/90]sub 2S/) and the aramid/epoxy (Kevlar-29, woven type, 8 ply) of ankle foot orthosis. The approach methods were as follows. 1) The history of impact load and impact energy due to the various velocities. 2) Relationship between the deflection and damage shape according to the impact velocities. 3) The behavior of absorbed energy and residual strength rate due to the various impact velocities.