• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.61-67
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• 2018

Objective: The human body is often modelled as a spring-mass system. Lower extremity stiffness has been considered to be one of key factor in the performance enhancement of running, jumping, and hopping involved sports activities. There are several different classification of lower extremity stiffness consisting of vertical stiffness, leg stiffness, joint stiffness, as well as muscle and tendon stiffness. The primary purpose of this paper was to review the literature and describe different stiffness models and discuss applications of stiffness models while engaging in sports activities. In addition, this paper provided a current update of the lower extremity literature as it investigates the relationships between lower extremity stiffness and both functional performance and injury. Summary: Because various methods for measuring lower extremity stiffness are existing, measurements should always be accompanied by a detailed description including type of stiffness, testing method and calculation method. Moreover, investigator should be cautious when comparing lower extremity stiffness from different methods. Some evidence highlights that optimal degree of lower extremity stiffness is required for successful athletic performance. However, the actual magnitude of stiffness required to optimize performance is relatively unexplored. Direct relationship between lower extremity stiffness and lower extremity injuries has not clearly been established yet. Overall, high stiffness is potentially associate risk factors of lower extremity injuries although some of the evidence is controversial. Prospective injures studies are necessary to confirm this relationship. Moreover, further biomechanical and physiological investigation is needed to identify the optimal regulation of the lower limb stiffness behavior and its impact on athletic performance and lower limb injuries.

• Archives of Plastic Surgery
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• v.36 no.1
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• pp.46-50
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• 2009

Purpose: Finger injury by green onion cutting machine is one of the common hand injuries in the kitchen. It has a unique feature: there are multiple parellel laceration 3 - 5 mm wide. There are two directions of injuries(vertical, oblique). It may involve bone, tendon, nerve, and vessel injuries. We discuss its management and the long - term progress. Methods: We have treated six patients from 2003 to 2007. We carried out low tension approximation with thin suture materials to avoid ischemia and performed the additional operation as nail bed repair, tenorrhaphy, open reduction, vessel anastomosis, and composite graft. We reviewed the record of initial injury and collected the follow - up record. Results: They were all middle aged - women who had worked in the kitchen. Right hand was dominent over left hand. The ratio of the directions was 3 : 3 (vertical : oblique). They were all competely healed although there were three atrophy, four hyperesthesia, and one nail deformity. Conclusion: Finger injury by green onion cutting machine is a unique pattern of laceration with various accompanied injuries. It may look like a severe form of injury, but in most cases have relatively favorable progress. We have to perform careful examination of accompanied injuries and carry out the proper management. First and foremost, the user especially in the middle aged women should be warned to be careful in handling this risky machine.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.4
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• pp.217-230
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• 2008

Objectives : The purpose of this study was to investigate the type, sites and period of injuries in Mixed Martial Arts. Methods : The questionnaire composed of 26 items was used as the research tool for this study. The respondents were 84 athletes of Mixed Martial Arts who participated in Spirit MC Amateur League in September, 2007. Data analysis use chi-square examination by SPSS$^{(R)}$ 12.0 program. Results : 1. Frequently, strikers are damaged at face and waist, grapplers are damaged at knee and waist. 2. Frequently, beginers are damaged at muscle and tendon, experts are damaged at bone and joint. 3. Age, career, specialty and injured type have significant correlations. 4. Age, career, training time and concern response have significant correlations. 5. Oriental medical treatment are friendly but not well-known to the athletes. Conclusions : Injuries of Mixed Martial Arts is multifactorial, so approach of athlete's individuality is important.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.161-173
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• 2003

This study was performed to investigate the kinematic and kinetic differences between functional walking shoe(FWS) and general sports shoe(GSS). The subjects for this study were 4 male adults who had the walking pattern of rearfoot strike with normal feet. The movement of one lower leg was measured using force platform and 3 video cameras while the subjects walked at the velocity of 2/1.5 m/s. The findings of this study were as follows 1. The angle of lower leg-ground and angle of knee with FWS was greater than with GSS at the moment of strike the floor and the moment of second peak ground reaction force. The decreasing rate of angle of ankle was smaller in FWS from the strike phase to the second peak ground reaction force. These mean upright walking and round walking along the shoe surface. 2. The maximal Increased angle of Achilles tendon and the minimal decreased angle of rearfoot were smaller in FWS very significantly(p<0.001). Thus FWS prevent the excessive pronation of ankle and have good of rear-foot control. 3. The vortical ground reaction force and the rate of it to the BW were smaller in FWS statistically(p<0.001). The loading rate was smaller in FWS, too, and thess represent the reduction of load on ankle joint and prevention of injuries on it.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.105-114
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• 2007

The purpose of this study was to compare the biomechanical difference of barefoot and two types taekwondo footwear. which will provide scientific data to coaches and players, to further prevent injuries and to improve each players skills. How to an effect on human body which studied a kinematics and kinetics from 8 college students during experiments. This study imposes several conditions by barefoot and two types of taekwondo footwear ran under average $2.56{\pm}0.21\;m$/sec by motion analysis, ground reaction force and electromyography that used to specific A company. First of all, motion analysis was caused by achilles tendon angle, angle of the lower leg, angle of the knee. The result of comparative analysis can be summarized as below. Motion analysis showed that statically approximates other results from achilles tendon angle (p<.01), initial ankle angle(p<.05), initial sole angle(p<.001) and barefoot angle(p<.001). Ground reaction force also showed that statically approximates other results from impact peak timing (p.001), Maximum loading rate(p<.001), Maximum loading rate timing (p<.001) and impulse of first 20 percent (p<.001). showed that averagely was distinguished from other factors, and did not show about that.

• Clinics in Shoulder and Elbow
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• v.22 no.3
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• pp.121-127
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• 2019

Background: Posterior decentering is not an uncommon finding on rotator cuff tear patients' shoulder magnetic resonance imaging. No previous study has reported on the relationship between posterior decentering and rotator cuff tear. Methods: We assessed patients' rotator cuff tear humeral head positions based on humeral-scapular alignment (HSA). Subjects were classified into centering and decentering groups based on a <2 mm or >2 mm HSA value, respectively. Differences in rotator cuff tear size, degree of tear, and fatty degeneration between the two groups were evaluated. Results: One hundred seventy-five patients (80 males, 95 females; mean age: $59.7{\pm}6.5$ years old) were selected as subjects (casecontrol study; level of evidence: 3). Tear size, degree of subscapularis tendon tear, and fatty degeneration of the supraspinatus, infraspinatus, and subscapularis muscles were significantly different between the two groups (p<0.001, p<0.001, p<0.001). Conclusions: The occurrence of decentering was related to rotator cuff tear size, degree of subscapularis tendon tear, and fatty degeneration of the rotator cuff muscles.

• Archives of Reconstructive Microsurgery
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• v.24 no.2
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• pp.62-67
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• 2015

Purpose: Pollicization typically involves surgical migration of the index finger to the position of the thumb. This procedure facilitates the conversion of a useless hand into a well-functioning one in patients who are not amenable to the toe-to-hand transfer. However, middle finger pollicization has been rarely reported. Materials and Methods: We reconstructed a thumb by immediate pollicization of the remnants of the middle finger in two patients who sustained a tumor and a trauma, respectively. The former, after cancer ablation was performed, has not been reported literally, and the latter involved free devitalized pollicization of the middle finger using a microsurgical anastomosis. The distal third extensor communis tendon was sutured to the proximal extensor pollicis longus tendon and the distal flexor digitorum superficialis and profundus were sutured to the proximal flexor pollicis longus. The abductor pollicis brevis tendon was sutured to the distal end of the first palmar interosseous muscle. Coaptation of the third digital nerve and the superficial radial nerve branch was performed. Results: Patients showed uneventful postoperative courses without complication such as infection or finger necrosis. Based on the principles of pollicization, a wide range of pinch and grasp movements was successfully restored. They were pleased with the functional and cosmetic results. Conclusion: Although the index finger has been the digit of choice for pollicization, we could also use the middle finger on specific occasions. This procedure provides an excellent option for the reconstruction of a mutilated thumb and could be performed advantageously in a single step.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.128-136
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• 1996

Radial nerve injury is caused by variety of etiologies, mainly traumatic. It is primarily a motor nerve and loss of it's function leads to a significant disability. Surgical treatments of radial nerve comprise of neurolysis(internal or external), neurorrhaphy(eineural, perineural or epi-perineural), nerve graft and tendon transfer. However, there is still controversies in treatment methods and time of operation. Authors experienced 23 cases of radial nerve injuries who were treated by operative methods and followed up over 1 year's duration. The male to female ratio was 18 to 5 and mean age was 30.7 years old. The causes were 13 cases in fractures, 5 cases in crushing injury, 3 cases in laceration, 1 case in CO poisoning and 1 case in unknown cause. The summary of the study were as follows ; 1. Excellent or good results were obtained in overall 16 cases among 23 cases; 5 of 9 cases in neurolysis, 3 of 3 cases in neurorrhaphy, 2 of 3 cases in nerve graft and 6 of 8 cases in tendon transfer. 2. In cases of neurorrhaphy and nerve graft, primary or delayed repair showed excellent or good results and neurolysis performed before 6 months leads to better results. But there was no correlations between the time of injury and operation in tendon transfer. 3. The radial nerve injury associated with extensive soft tissue defect or any conditions that leads to nerve ischemia results poor prognosis. 4. The patients aged under 40 years showed better prognosis in clinical results according to the age of surgical treatment. 5. If the surgeon decide the method and the time of operation through the exact evaluation of the factors which influencing the end result such as age of the patient, level and type of injury, extent of nerve lesion and the associated tissue injury, good result could be expected.

• Archives of Plastic Surgery
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• v.43 no.2
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• pp.134-144
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• 2016

In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana's classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning.

• Advances in biomechanics and applications
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• v.1 no.3
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• pp.169-185
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• 2014

Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).