Korean Journal of Sport Biomechanics最新文献

{"title":"Effect of Taping Therapy and Inner Arch Support on Plantar Lower Body Alignment and Gait","authors":"Sojung Lee, Dawun Jeong, Dong-Eun Kim, Kyungock Yi","doi":"10.5103/KJSB.2017.27.3.229","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.3.229","url":null,"abstract":"The feet not only support the human body when standing but also absorb and distribute the impact from weight during walking (Seoul National University Hospital, 2003). For this main role, the foot has a unique structure called the arch (Kang, 2012). The foot has four arches, including the medial and lateral arches, and the anterior transverse arches of the forefoot and midfoot. Loss of the foot arch is associated with loss of dorsiflexion and plantarflexion abilities of the ankle joint, which is important for shock absorption, and may lead to various disabilities (SNUH, 2003). The pes planus, with the medial foot arch lowered and the entire sole of the foot touching the floor, leads to inadequate gait due to decreased impact absorption of the foot and excessive pronation movement (Song, 2008) and may accompany not only spasticity and heel pain, but also the hallux valgus or plantar fasciitis (Ministry of Health and Welfare, 2016). The results of the footprint analysis performed for women in their 20~50s by the Korea Foot Health Association indicated that 84.8% of the women showed arch deformities such as pes planus and pes cavus, and 54.5% had hallux valgus (Lee, 2006). Thus, a taping technique and foot support to relieve or treat the symptoms of arch-foot deformity are needed (Lee et al., 2006). Taping is used for the prevention of injuries and any recurrence on the injured areas, and has a positive effect on the range of motion of the joints, joint fixation and muscle compression, and joint strength and muscle fatigue (Kang, Kim, & Lee, 2010; Park, 2008). Moreover, taping therapy applied to the ankle area reduces inversion and eversion of the ankle and affects the range of motion (Choi, 2007). In particular, foot taping therapy improves exercise performance by alleviating the pain during walking and induces a positive structural change to the foot arch (Jang et al., 2008; Lee, Kim, & Choi, 2009). The force loaded on the feet daily is approximately 700 tons, while the feet takes more than 3,000,000 steps per year for a 70-kg person walking 10,000 steps per day (Lee, 2001). According to previous studies Korean Journal of Sport Biomechanics 2017; 27(3): 229-238 http://dx.doi.org/10.5103/KJSB.2017.27.3.229 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125380880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationship between Center of Pressure and Local Stability of the Lower Joints during Walking in the Elderly Women","authors":"Jiseon Ryu","doi":"10.5103/KJSB.2017.27.2.133","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.133","url":null,"abstract":"Objective: The purpose of this study was to determine the relationship between center of pressure (CoP) and local stability of the lower joints, which was calculated based on approximate entropy (ApEn) during walking in elderly women. Method: Eighteen elderly women were recruited (age: 66.4±1.2 yrs; mass: 55.4±8.3 kg; height: 1.56±0.04 m) for this study. Before collecting data, reflective marker triads composed of 3 non-collinear spheres were attached to the lateral surface of the thigh and shank near the mid-segment to measure motion of the thigh and shank segments. To measure foot motion, reflective markers were placed on the shoe at the heel, head of the fifth metatarsal, and lateral malleolus, and were also placed on the right anterior-superior iliac spine, left anterior-superior iliac spine, and sacrum to observe pelvic motion. During treadmill walking, kinematic data were recorded using 6 infrared cameras (Oqus 300, Qualisys, Sweden) with a 100 Hz sampling frequency and kinetic data were collected from a treadmill (Instrumented Treadmill, Bertec, USA) for 20 strides. From kinematic data, 3D angles of the lower extremity's joint were calculated using Cardan technique and then ApEn were computed for their angles to evaluate local stability. Range of CoP was determined from the kinetic data. Pearson product-moment and Spearman rank correlation coefficient were applied to find relationship between CoP and ApEn. The level of significance was determined at p <.05. Results: There was a negative linear correlation between CoP and ApEn of hip joint adduction-abduction motion ( p <.05), but ApEn of other joint motion did not affect the CoP. Conclusion: It was conjectured that ApEn, local stability index, for adduction/abduction of the hip joint during walking could be useful as a fall predictor.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125214956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Counter-rotation Position on Knee/Hip Angulation, Center of Mass Inclination, and Edging Angle in Simulated Alpine Skiing","authors":"Sukhoon Yoon, Jin-hae Kim, Jae-Hyeon Park, Jiseon Ryu, Sang-Kyoon Park, Joo-Nyeon Kim","doi":"10.5103/KJSB.2017.27.2.91","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.91","url":null,"abstract":"Objective: To investigate rotation movement of segment for performing each position and its effect on knee/hip angulation, COM inclination, and edging angle changes. \u0000Method: Twelve Alpine skiers (age: 25.8±4.8 years, height: 173.8±5.9 cm, weight: 71.4±7.4 kg, length of career: 9.9±4.6 years) participated in this study. Each skier was asked to perform counter-rotation, neutral, and rotation positions. \u0000Results: Shank and thigh were less rotated in the counter-rotation position than in other positions, whereas the trunk and pelvis were more counter-rotated (p<.05). Hip angulation, COM inclination, and edging angle were significantly greater in the counter-rotation position than in other positions (p<.05). \u0000Conclusion: Our finding proved that the counter-rotation position increases hip angulation, COM inclination, and edging angle. Consequently, we suggest that skiers should perform counter-rotation of the trunk and pelvis relative to the ski direction in the vertical axis for the counter-rotation position. Further analysis will continue to investigate the effects of the counter-rotation position in real ski slope with kinetic analysis.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127010409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Countermovement Jump Strategy Changes with Arm Swing to Modulate Vertical Force Advantage","authors":"Seyoung Kim","doi":"10.5103/KJSB.2017.27.2.141","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.141","url":null,"abstract":"Objective: We obtained force-displacement curves for countermovement jumps of multiple heights and examined the effect of an arm swing on changes in vertical jumping strategy. Countermovement jumps with hands on hips (Condition 1) and with an arm swing (Condition 2) were evaluated to investigate the mechanical effect of the arm movement on standing vertical jumps. We hypothesized that the ground reaction force (GRF) and/or center of mass (CoM) motion resulting from the countermovement action would significantly change depending on the use of an arm swing. \u0000Method: Eight healthy young subjects jumped straight up to five different levels ranging from approximately 10% (~25 cm) to 35% (~55 cm) of their body heights. Each subject performed five sets of jumps to five randomly ordered vertical elevations in each condition. For comparison of the two jumping strategies, the characteristics of the boundary point on the force-displacement curve, corresponding to the vertical GRF and the CoM displacement at the end of the countermovement action, were investigated to understand the role of arm movement. \u0000Results: Based on the comparison between the two conditions (with and without an arm swing), the subjects were grouped into type A and type B depending on the change observed in the boundary point across the five different jump heights. For both types (type A and type B) of vertical jumps, the initial vertical force at the start of push-off significantly changed when the subjects employed arm movement. \u0000Conclusion: The findings may imply that the jumping strategy does change with the inclusion of an arm swing, predominantly to modulate the vertical force advantage (i.e., the difference between the vertical force at the start of push-off and the body weight).","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130210017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Skill Level and Feet Width on Kinematic and Kinetic Variables during Jump Rope Single Under","authors":"Kyeong Hui Jang, M. Son, Dae Young Kim, Myeounggon Lee, You Kyung Kim, Jin-Heem Kim, C. Youm","doi":"10.5103/KJSB.2017.27.2.99","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.99","url":null,"abstract":"Objective: The purpose of this study was to analyze the effects of skill level and width between feet on kinematic and kinetic variables during jump rope single under with both feet. \u0000Method: Fifteen subjects in the skilled group (age: 10.85±0.40 yrs, height: 142.13±5.41 cm, weight: 36.97±6.65 kg) and 15 subjects in the unskilled group (age: 10.85±0.40 yrs, height: 143.31±5.54 cm, weight: 40.81±10.39 kg) participated in this study. \u0000Results: Participants in the skilled group minimized the anteroposterior displacement of their center of mass by modifying the width between their feet and decreased the range of motion (ROM) of their trunk in the sagittal plane. The preferred width during the jump rope decreased by 5.61~6.11 cm (32~37%) in comparison to width during static standing. The induced width was increased by 16.44~16.67 cm (82~85%), regardless of skill level. The kinematic variables of the left and right legs of members of the unskilled group were significantly different from those of members in the skilled group regarding the ROM of the hip, knee, and ankle joint. Otherwise, the members of the skilled group were consistent in terms of the kinematic variables of the right and left legs. \u0000Conclusion: The preferred width between feet during the jump rope was found to be beneficial for maintaining dynamic stability. The unskilled group exhibited asymmetry in left and right motion within the ranges of motion of the ankle, knee, and hip joints, regardless of the width. Therefore, long-term accurate jump rope motions will contribute to an improvement in the left and right imbalances of the entire body.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124561792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Targeted Knee Flexion Angle on the Biomechanical Factors of Upward and Downward Phases during Forward Lunge","authors":"Y. Lim, Jun Sung Park, Jae Woo Lee, Moonseok Kwon","doi":"10.5103/KJSB.2017.27.2.125","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.125","url":null,"abstract":"Objective: The aim of this study was to investigate the effect of targeted knee flexion angle on biomechanical factors of knee joint between upward and downward phases during the forward lunge. Method: Eight elderly subjects (age: 22.23 ± 1.51 years, weight: 69 ± 6.63 kg, height: 174.88 ± 6.85 cm) participated in this study. All reflective marker data and ground reaction force during a forward lunge were collected. The knee joint movement and reaction force and joint moment at maximum knee flexion angle were compared by repeated measures one-way analysis of variance (ANOVA) ( p <.05). The peak knee joint reaction force and joint moment between upward and downward phases were compared by repeated measures two-way ANOVA ( p <.05). Results: The anterior and vertical knee joint movements, reaction force, and extensor moment of 80° targeted knee flexion condition at maximum knee flexion angle was greater than both 90° and 100° conditions ( p <.05). The 80° knee flexed angle condition had greater peak joint reaction force and extensor moment compared with both 90° and 100° conditions between upward and downward phases during the forward lunge. Conclusion: As the targeted knee joint flexion angle increases, knee joint movement and kinetic variables become greater during the forward lunge exercise.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122000663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relationship between Leg Stiffness and Kinematic Variables According to the Load while Running","authors":"Seung-Hyun Hyun, Che-Cheong Ryew","doi":"10.5103/KJSB.2017.27.2.109","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.109","url":null,"abstract":"Objective: This study aimed to investigate the relationship between leg stiffness and kinematic variables according to load while running. \u0000Method: Participants included eight healthy men (mean age, 22.75 ± 1.16 years; mean height: 1.73 ± 0.01 m; mean body weight, 71.37 ± 5.50 kg) who ran with no load or a backpack loaded with 14.08% or 28.17% of their body weight. The analyzed variables included leg stiffness, ground contact time, center of gravity (COG) displacement and Y-axis velocity, lower-extremity joint angle (hip, knee, ankle), peak vertical force (PVF), and change in stance phase leg length. \u0000Results: Dimensionless leg stiffness increased significantly with increasing load during running, which was the result of increased PVF and contact time due to decreased leg lengths and COG displacement and velocity. Leg length and leg stiffness showed a negative correlation (r = -.902, R2 = 0.814). COG velocity showed a similar correlation with COG displacement (r = .408, R2 = .166) and contact time (r = -.455, R2 = .207). \u0000Conclusion: Dimensionless leg stiffness increased during running with a load. In this investigation, leg stiffness due to load increased was most closely related to the PVF, knee joint angle, and change in stance phase leg length. However, leg stiffness was unaffected by change in contact time, COG velocity, and COG displacement.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132981459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Stability on Single-leg Standing by Wearing a Head Mounted Display","authors":"B. Woo","doi":"10.5103/KJSB.2017.27.2.149","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.149","url":null,"abstract":"Objective: The purpose of this study was to investigate the effects of three visual conditions (eyes opened, eyes closed, and wearing of a head mounted display [HMD]) on single-leg standing through kinematics and kinetic analysis. Method: Twelve college students (age: 24.5 ± 2.6 years, height: 175.0 ± 6.4 cm, weight: 69.2 ± 5.1 kg) participated in this study. The study method adopted three-dimensional analysis with six cameras and ground reaction force measurement with one force plate. The analysis variables were coefficient of variation (CV) of the center of body mass, head movement, ground reaction force, and center of pressure, which were analyzed using one-way analysis of variance with repeated measures according to visual conditions. Results: In most cases, the results of this study showed that the CV was significantly higher in the order of HMD wearing, eyes closed, and eyes opened conditions. Conclusion: Our results indicated that body sway was the largest in the HMD wearing condition, and the risk of falling was high owing to the low stability.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122436229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Short-term Muscle Vibration on Knee Joint Torque and Muscle Firing Patterns during a Maximal Voluntary Isometric Contraction","authors":"Jiseop Lee, Junkyung Song, Jooeun Ahn, Jaebum Park","doi":"10.5103/KJSB.2017.27.2.83","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.83","url":null,"abstract":"Objective: To investigate the effect of short-term vibration frequencies on muscle force generation capabilities. \u0000Method: Six healthy participants were recruited for this study and only their dominant leg was tested. The subjects were tested under five conditions of vibration frequencies with constant amplitude: 0 Hz (no vibration), 30 Hz, 60 Hz, and 90 Hz, and the vibration amplitude was 10 mm for all frequency conditions. The vibration was applied to the rectus femoris (RF). The subjects were then instructed to maintain a steadystate isometric knee joint torque (100 Nm) for the first 6 s. After the steady-state torque production, the subjects were required to produce isometric knee joint torque by leg extension as hard as possible with a start signal within the next 3 s. The vibration was applied for ~4 s starting from 1 s before initiation of the change in the steady-state knee joint torque. \u0000Results: The results showed that the maximum voluntary torque (MVT) of the knee joint increased with the vibration frequencies. On average, the MVTs were 756.47 Nm for 0 Hz (no vibration) and 809.61 Nm for 90 Hz. There was a significant positive correlation (r = 0.71) between the MVTs and integrated electromyograms (iEMGs). Further, the co-contraction indices (CCIs) were computed, which represent the ratio of the iEMGs of the antagonist muscle to the iEMGs of all involved muscles. There was a significant negative correlation (r = 0.62) between the CCIs and MVTs, which was accompanied by a significant positive correlation (r = 0.69) between the iEMGs of the vibrated muscle (RF). There was no significant correlation between the MVTs and iEMGs of the antagonist muscle. \u0000Conclusion: The results of this study suggest that the short-term vibration on the muscle increases the level of muscle activation possibly owing to the increased Ia afferent activities, which enhances the muscle force generation capability.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132931210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Kinetic Degrees of Freedom of the Fingers on the Task Performance during Force Production and Release: Archery Shooting-like Action","authors":"Kim， Ki-tae, Dayuan Xu, Park Jaebum","doi":"10.5103/KJSB.2017.27.2.117","DOIUrl":"https://doi.org/10.5103/KJSB.2017.27.2.117","url":null,"abstract":"Objective: The purpose of this study was to examine the effect of changes in degrees of freedom of the fingers (i.e., the number of the fingers involved in tasks) on the task performance during force production and releasing task. Method: Eight right-handed young men (age: 29.63±3.02 yr, height: 1.73±0.04 m, weight: 70.25±9.05 kg) participated in this study. The subjects were required to press the transducers with three combinations of fingers, including the index-middle (IM), index-middle-ring (IMR), and index-middle-ring-little (IMRL). During the trials, they were instructed to maintain a steady-state level of both normal and tangential forces within the first 5 sec. After the first 5 sec, the subjects were instructed to release the fingers on the transducers as quickly as possible at a self-selected manner within the next 5 sec, resulting in zero force at the end. Customized MATLAB codes (MathWorks Inc., Natick, MA, USA) were written for data analysis. The following variables were quantified: 1) finger force sharing pattern, 2) root mean square error (RMSE) of force to the target force in three axes at the aiming phase, 3) the time duration of the release phase (release time), and 4) the accuracy and precision indexes of the virtual firing position. Results: The RMSE was decreased with the number of fingers increased in both normal and tangential forces at the steady-state phase. The precision index was smaller (more precise) in the IMR condition than in the IM condition, while no significant difference in the accuracy index was observed between the conditions. In addition, no significant difference in release time was found between the conditions. Conclusion: The study provides evidence that the increased number of fingers resulted in better error compensation at the aiming phase and performed a more constant shooting (i.e., smaller precision index). However, the increased number of fingers did not affect the release time, which may influence the consistency of terminal performance. Thus, the number of fingers led to positive results for the current task.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124955941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}