Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.

Understanding sciences behind fall-related hip fractures in older adults is important to develop effective interventions for prevention. The aim of this review is to provide biomechanical understanding and prevention strategies of falls and related hip fractures in older adults, in order to guide future research directions from biomechanical perspectives. While most hip fractures are due to a fall, a few of falls are injurious causing hip fractures, and most falls are non-injurious. Fall mechanics are important in determining injurious versus non-injurious falls. Many different biomechanical factors contribute to the risk of hip fracture, and effects of each individual factors are known well. However, combining effects, and correlation and causation among the factors are poorly understood. While fall prevention interventions include exercise, vision correction, vitamin D intake and environment modification, injury prevention strategies include use of hip protectors, compliant flooring and safe landing strategies, vitamin D intake and exercise. While fall risk assessments have well been established, limited efforts have been made for injury risk assessments. Better understanding is necessary on the correlation and causation among factors affecting the risk of falls and related hip fractures in older adults. Development of the hip fracture risk assessment technique is required to establish more efficient intervention models for fall-related hip fractures in older adults.

Background: Genu varum is also known as bow leg. It is a deformity wherein there is lateral bowing of the legs at the knee. it does give rise to pain, and persistent bowing can often give rise to discomfort in knees, hips and ankles. Objects: This study investigated the effect of narrow squats on the knee joint during a gait and distance between the knees of person with genu varum. Methods: This study analyzed 23 patient with genu varum that grade Ⅲ, 12 narrow squat group and 11 genenal squat group in motion analysis laboratory. The subjects of experiment took gait before and after intervention, the range of joint motion, moment of knee joint adduction, power, distance of the knees were measured. And in order to make an analysis between groups, an paiered t-test and independent t-test was carried out. For statistical significance testing, it was decided that significance level α be .05. Results: It was shown that the group of narrow squat exercise significantly decreased in distance of knees (p<.05),In moment of adduction of knee joint, it was shown to significantly decrease in two groups (p<.05), was significantly decreased in adduction, abduction, and rotation (p<.05). In relation of peak-knee adduction moment and valgus angle, there was significant decrease in narrow squat group (p<.05). Conclusion: When the above result of study were examined, a narrow squat exercise given to the genu varum patients significantly decreased the distance between the knees, range of knee adduction and abduction, knee adduction moment, knee power. And stability gains through the decrease of excursion of knee medial part be effective for the correction of genu varum deformation.

Background: It is very difficult for hemiplegic patients to effectively perform the sit-to-stand (STS) movements independently because of several factors. Moreover, the analysis of STS motion in hemiplegic patients has been thus far confined to only muscle strength evaluation with little information available on structural and environmental factors of varying chair height and foot conditions. Objects: This study aimed to analyze the change in biomechanical factors (ground reaction force, center of mass displacement, and the angle and moment of joints) of the joints in the lower extremities with varying chair height and foot conditions in hemiplegic patients while they performed the STS movements. Methods: Nine hemiplegic patients voluntarily participated in this study. Their STS movements was analyzed in a total of nine sessions (one set of three consecutive sessions) with varying chair height and foot conditions. The biomechanical factors of the joints in the lower extremities were measured during the movements. Ground reaction force was measured using a force plate; and the other abovementioned parameters were measured using an infra-red camera. Two-way repeated analysis of variance was performed to determine the changes in biomechanical factors in the lower extremities with varying chair height and foot conditions. Results: No interaction was found between chair height and foot conditions (p>.05). All measured variables with varying chair height showed a significant difference (p<.05). Maximum joint flexion angle, maximum joint moment, and the displacement of the center of mass in foot conditions showed a significant difference (p<.05); however the maximum ground reaction force did not show a significant difference (p>.05). Conclusion: The findings suggest that hemiplegic patients can more stably and efficiently perform the STS movement with increased chair height and while they are bare-foot.

수공구 사용시 과도한 힘은 작업성 근골격계 질환을 일으킬 수 있는 주요 원인중 하나이다. 이와 관련하여, 수공구 파지시 인체 내부에 부과되는 근력과 외적으로 작용된 힘 간의 비율을 이해하는 것이 중요하며, 이는 근육에 부과되는 과도한 힘을 최소화 시키고, 작업에 필요한 힘의 효율성을 극대화 시키는데 필수적이라 할 수 있다. 이러한 비율과 관련하여 많은 연구가 되어 왔으나, 대부분 수리적 인체역학적 모델과 같은 간접적 추정 방법에 의거하고 있는 실정이다.

With the growth of scientific technology, the development of method and instrument has contributed to the study of Sports Biomechanics. It is considered that the paradigm of researching would be radically changed. Hence, the aim of this study is to analyz

The purpose of this study was to improve the development of korea sports biomechanics study. and This study will offer to basic data to development of sports biomechanics as review a domestic study tendency regarding sports biomechanics of recent five yea

The purpose of this study was to define more precisely the anatomy of the thumb flexor pulley system and to determine the relative contribution of each of the pulleys to the biomechanics of thumb motion at the metacarpophalangeal (MP) and interphalangeal (IP) joints. For this, 22 hands from 11 cadavers were used and randomly assigned to two groups. In the first group, the first annular (A1) pulley was cut first followed by the variable annular (Av) pulley and then the oblique pulley. In the second group, the oblique pulley was cut first followed by the, pulley and then the Av pulley. In 7 of 22 hands, it was a transverse structure parallel to the, pulley with a gap between the A1 and Av pulleys, referred to here as type I. In 9 hands, the A1 and Av pulleys were connected without any gap (type II). In 6 hands, the space between the A1 and Av pulleys were triangular in shape with fibers of the Av pulley converging toward the radial side (type III). In biomechanical study of both first and second experiments, there was no significant difference in MCP joint flexion between the all intact, A1 section, A1/Av section, A2 intact (A1/Av/oblique section), and no pulley configuration (p>.05). In occurring displacements less than 10 mm, there was no significant difference in IP joint flexion (p>.05). However, there was a significant decrease in IP joint flexion occurred in both 15 mm and 20 mm excursion (p<.05), when the oblique pulley was resected additionally after cutting the A1 and Av pulleys in first experiment, and when the A1 pulley was resected additionally after cutting the oblique pulley. According to the results, the injury of only the oblique pulley does not decrease thumb motion significantly. The oblique pulley injury with both the A1 and Av pulleys laceration decreased thumb motion significantly. The additional laceration of the A2 pulley does not decrease thumb motion.

The purpose of this paper is to provide the reader with a pertinent information and research trends of biomechanics in wheelchair propulsion. Biomechanical studies for wheelchair propulsion mainly focus on the most suitable propulsion performance and methods for preventing upper extremity injuries. Recent issues have concentrated on wheelchair propulsion style and cycle mainly because of the high prevalence of repetitive strain injuries in the upper extremely such as shoulder impingement and carpel tunnel syndrome. Optimizing wheelchair propulsion performances as well as medical reflections are presented throughout the review. Information on the underlying musculoskeletal mechanisms of wheelchair propulsion has been introduced through a combination of data collection under experimental conditions and a more fundamental mathematical modelling approach. Through a synchronized analysis of the movement pattern and muscular activity pattern, insight has been gained in the wheelchair propulsion dynamics of people with a different level of disability (various level of physical activity and functional potential). Through mathematical modelling simulation, and optimization (minimizing injury and maximizing performance), underlying musculoskeletal mechanisms during Wheelchair propulsion is investigated.

This paper presents the kinematic modeling of the human forearm rotation constructed with a spatial four-bar linkage. Especially, a circumduction of the distal ulna is modeled for a minimal displacement of the position of the hand during the forearm rotation from the supination to the pronation. To establish its model, four joint types of the four-bar linkage are, firstly, assigned with the reasonable grounds, and then the spatial linkage having the URUU (Universal-Revolute-Universal-Universal) joint type is proposed. Kinematic analysis is conducted to show the behavior of the distal radio-ulna as well as to evaluate the angular displacements of all the joints. From the simulation result, it is, finally, revealed that the URUU spatial linkage can be substituted for the URUR (Universal-Revolute-Universal-Revolute) spatial linkage by a kinematic constraint.

본 연구는 최근 유행하고 있는 minimal신발이 달리기 시 하지의 생체역학 및 안전성에 어떠 한 영향을 미치는가를 알아보는데 그 목적이 있다. 본 연구의 실험에 동원된 피험자는 건강한 남자대학생 16명이었으며 맨발, minimal신발, 일반 런닝화를 대상으로 영상분석장비와 지면반 력측정장비를 이용하여 4m/sec의 속도로 달리기를 할 때 하지동작을 촬영하여 분석한 결과 다 음과 같은 결론을 얻었다. 발의 초기 회내운동과 총 회내운동은 맨발과 minimal신발의 경우 일반 운동화에 비하여 너 무 크거나 작게 나타나서 충격력흡수에 문제가 발생할 수 있다. 압축각과 뒤틀림각은 맨발과 minimal신발이 일반 런닝화에 비하여 더 크게 나타나서 발의 안전성에 부정적인 영향을 미칠 수 있다. 최대충격력과 최대충격력부하율, 최대수직지면반력부하율은 minimal신발이 맨발이나 일반 런닝화에 비하여 크게 나타났다. 부위별 최대압력은 M6를 제외하고 전반적으로 통계적인 차이를 나타내지 않았지만 minimal신발이 일반 런닝화보다 더 크게 나타났다. 본 연구결과를 종합해볼 때 후족제어변인과 충격흡수변인에서 minimal신발이 일반 런닝화에 비하여 충격력흡수가 잘 안되기 때문에 반복적이고 장기적인 관점에서 부상을 유발할 가능성 이 크다고 할 수 있다. 또한 minimal신발이 맨발의 기능과 유사하도록 개발되었다고 하지만 본 연구결과 여러 분석변인에서 맨발과 minimal신발 사이에 차이를 나타냈기 때문에 맨발의 기능을 모방한 신발을 제작하기는 결코 쉽지 않다고 할 수 있다.