Korean Journal of Sport Biomechanics最新文献

{"title":"Gait Stability in K-pop Professional Dancers","authors":"Young-Kwan Jang, Su-yeon Hong, In-Young Jang","doi":"10.5103/KJSB.2016.26.4.377","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.4.377","url":null,"abstract":"Objective: The purpose of this study was to provide data on gait characteristics of K-pop professional dancers. Method: Participants were divided into four groups: male dancers (n=10, age: 28.2 ± 3.4 years, height: 175 ± 6 cm, weight: 68.9 ± 5.6 kg), female dancers (n=10, age: 26.7 ± 3.1 years, height: 162 ± 4 cm, weight: 52.1 ± 3.7 kg), non-dancer males (n=10, age: 25.2 ± 2.6 years, height: 171 ± 6 cm, weight: 66.4 ± 5.3 kg), or non-dancer females (n=10, age: 26.2 ± 3.0 years, height: 161 ± 5 cm, weight: 56.4 ± 6.7 kg). Twelve infrared cameras (Qualisys, Oqus 500, Sweden, 150 Hz.) were used to capture three-dimensional motion data. Gait motion data of professional dancers and ordinary persons were obtained. Results: K-pop dancers' dynamic stability during the female toe off event and the male heel contact event was better compared with that of ordinary persons in the front-rear direction. In addition, the results showed a significant difference in the margin of stability (MoS). However, the medial-lateral direction of both female and male dancers during heel contact and the toe off event was more stable compared with ordinary person, who exhibited an increased MoS than did the dancers. Conclusion: This study aimed to investigate the gait characteristics of K-pop professional dancers in comparison with ordinary persons using gait parameters and MoS. The stability of K-pop professional dancers' dynamic gait in the front-rear direction was better than that in the medial-lateral direction. Therefore, further studies in which the dance movements of K-pop dancers are sub-divided and analyzed will be necessary to reduce related injury.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126512800","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":"Biomechanical Analysis of Muscle Fatigue and Ground Reaction Force for the Development of Outdoor Walking Shoes","authors":"Young-Min Jang, J. Lee, Jeongok Yang, Bom-jin Lee","doi":"10.5103/KJSB.2016.26.4.413","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.4.413","url":null,"abstract":"Objective: The purpose of this study was to analyze and compare different kinds of outdoor walking shoes in terms of muscle fatigue and ground reaction force on walking, and to provide foundational data for developing and choosing outdoor walking shoes that fit the users. Method: The study subjects were 30 healthy men. The experiment was conducted by using outdoor walking shoes with different inner and outer harnesses of the midsole, and shapes of the outsole. For data collection, electromyography was used to measure the muscle fatigue of the anterior tibial muscle and gastrocnemii, which contribute to the dorsiflexion and plantarflexion of the ankle joint, and the biceps muscle of the thigh and lateral great muscles, which contribute to the flexion and extension of the knee joint. A GRF measurement device was used to measure the X , Y , and Z axes. Results: In the type A outdoor walking shoes, regarding the hardness of the midsole, the inner part was soft, while the outer part was hard. The vertical ground reaction force was the lowest, which means least impact while walking and light load to the knees and ankles. The type C outdoor walking shoes were intended to provide a good feel in wearing the shoes. The tibialis anterior, biceps femoris, and gastrocnemii indicate low fatigue, which means that during a long-distance walk, it will minimize the fatigue in the muscles of the lower limbs. Conclusion: To sum up the study results, the different types of outdoor walking shoes indicate their unique characteristics in the biomechanical comparison and analysis. However, the difference was not statistically significant. Thus, a systematic and constant follow-up research should be conducted to cope with expanding market for outdoor walking shoes. Lastly, this study is expected to present foundational data and directions for developing outdoor walking shoes.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131351879","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":"Differences in Rectus Femoris Activation Among Skaters Wearing Fabric Speed Skating Suits with Different Levels of Compression","authors":"Y. Moon, Jooho Song, Jin-Sup Hwang","doi":"10.5103/KJSB.2016.26.4.421","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.4.421","url":null,"abstract":"In a speed skating simulation study, Saetran (2008) reported that different race suits could produce a difference of 3 seconds in a 1,500-m race. Given that the difference between the first and second place in the 1,500-m final at the 2014 Sochi Winter Olympics was only 0.003 seconds (Lee et al., 2014), the small effect of the suit and apparatus can have a major impact on the outcome of a race. Thus, the importance of sportswear is receiving increasing attention (Brownlie et al., 2004). As scientific and differentiated equipment reduces friction, improves motor efficiency, and has a positive impact on athletic ability, active athletes consider their personal equipment and clothing to be important, and are quick to adopt innovative, proven equipment if it could help them achieve even slightly better results. Recently, race suits for athletes have focused on the development of functional clothing that reduces muscle fatigue by limiting the size of large muscle movements during exercise. Compression clothing improves athletic performance, and alleviates post-exercise muscle pain and tissue damage. Kraemer et al. (2010) and Doan et al. (2003) reported that even simple compression stockings contribute to reducing fatigue (Berry & McMurray, 1987) and improving muscle power (Done et al., 2003). Takarada (2002) implemented blood flow restriction training in the lower limb and reported a 15% improvement in muscle strength and a 10% increase in cross-sectional muscle area. Based on the observation that compression reduces edema, and improves venous and lymphatic return, Chatham and Thomas (2013) suggested that compression improved muscle strength by increasing blood circulation. However, Ebersole (2006) found no significant differences in peak torque, total work, or peak power at different levels of compression. Thus, opinions vary on the effectiveness of compression clothing. Moreover, it has not been clearly demonstrated that compression is effective in improving athletic performance. Nevertheless, compression clothing is receiving attention worldwide from elite athletes, both in intense competitions and leisure sports (Fu et al., 2012). Efforts have been made to develop samples or products that can improve athletic performance through compression clothing. Therefore, based on a functional coated fabric applied to the femoral region of speed skating suits (developed as part of a nationally funded project to develop textiles, led by the Korea Evaluation Institute of Industrial Technology), the present study analyzed how different levels of compression affected the maximum power and activation of the rectus femoris, which produces the most power during racing, with the aim of assisting the future manufacture of speed skating suits. Korean Journal of Sport Biomechanics 2016; 26(4): 421-426 http://dx.doi.org/10.5103/KJSB.2016.26.4.421 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126074445","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":"Comparison of Three-dimensional Kinematic Changes of the Lower Extremity between the Two Different Braking Distances of Snowplow in Alpine Skiing","authors":"Kim， Joonyeon, 김진해, Jiseon Ryu, Sukhoon Yoon, Sang-Kyoon Park","doi":"10.5103/KJSB.2016.26.4.361","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.4.361","url":null,"abstract":"Objective: The aim of this study was to compare three-dimensional kinematic changes of the lower extremity between the two different braking distances during snowplow in alpine skiing. Method: Six alpine ski instructors (age: 25.3 ± 1.5 yr, height: 169.3 ± 2.9 cm, weight: 66.2 ± 5.9 kg, career: 4.2 ± 2.9 yr) participated in this study. Each skier was asked to perform snowplow on the two different braking distances (2 and 4 m). Results: Snowplow and edging angles (p = .006 and p = .005), ankle adduction and inversion (p = .033 and p = .002), knee extension (p = .003), and hip abduction and internal rotation (p = .043 and p = .006) were significantly greater in the 2 m than in the 4 m braking distance. Conclusion: Based on our results, we suggest that skiers should make greater snowplow and edging angles on the shorter braking distance. In this situation, ankle joint adduction/inversion angle and hip joint internal-rotation make greater snowplow angle, and hip joint abduction make greater edging angle. In addition, greater knee joint extension angle may lead to more posteriorly positioned center of mass.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126886385","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 Development of Rhythmic Balance Training Equipment and its Effect on Performance for Elderly","authors":"Da Won Park, C. Won, Sung Ro Lee, Y. Park","doi":"10.5103/KJSB.2016.26.3.323","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.323","url":null,"abstract":"The elderly accounted for 13.1% of the entire population of Korea in 2015, with 6,624,000 individuals, and are projected to account for 40% of the total population in 2060. The drastic increase in medical expenses for the elderly (3,220,000 Won per person in 2014) is becoming a social problem (StatisticsKorea, 2015). From a social welfare point of view, the idea of disseminating various types of exercise equipment to reduce medical expenses for the elderly is spreading (Josephs, Pratt, Meadows, Thurmond, & Wagner, 2016). Exercise training programs for the elderly have evolved in different ways. Korean exercise training programs such as Pilates (Kim, Rhyu, & Hong, 2011; Kang & Jon, 2014), walking (Choi & Lee, 2013; Kim & Beak, 2016), and step box (Kim, Choi, & Kim, 2016) have been used to promote exercise among the elderly. Internationally, training programs using dance (Kattenstroth, Kolankowska, Kalisch, & Dinse, 2010; Rahal et al., 2015), resistance bands (Wessner, 2016; Nemček & Simon, 2016; Oh et al., 2016), square-stepping exercise (Teixeira et al., 2013_ENREF_17; Jindo et al., 2016), and resistance with dumbbells, barbells, or cable have been recently used among the elderly (Peltonen, Arokoski, Kallinen, & Pullinen, 2012). A 2013 study by Jorgensen, Laessoe, Hendriksen, Nielsen, & Aagaard reported that most training programs for the elderly are composed of simple exercises, and more entertaining programs are needed to replace monotonous exercise programs. Park, Kim, Kim, Lee & Lim in 2010 also emphasized the need for development of an exercise program for the elderly with music and choreography to maintain interest. Nintendo's Wii Fit (Jorgensen et al., 2013), which was developed in Japan, maintains the user's interest by providing numerous programs such as yoga, strength and cardiovascular exercise training, and balance games. Because Wii Fit is a program in which the user simply repeats the motion shown on the screen, it is debatable whether Wii Fit can effectively provide exercise training with only the user's weight and strength. Only a few pieces of exercise equipment designed for the elderly are used in Korea and overseas. As several previous studies show, exercise training for the elderly has mostly been conducted using tools (tilting boards, foam plates, dumbbells, and resistance training machines) rather than equipment (Gillespie et al., 2009; Patil et al., 2015). Many pieces of exercise equipment have been developed for the elderly with a focus on rehabilitation, however. In Japan, water resistance equipment has been developed in which the user wears sock-like devices and walks forward in water to increase lower limb strength and balance (Katsura KJSB Korean Journal of Sport Biomechanics 2016; 26(3): 323-331 http://dx.doi.org/10.5103/KJSB.2016.26.3.323 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"63 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130615733","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 Forefoot Bending Angle in Sprint Spikes According to Bobsleigh Start Lap Time for Development of Korean-Specific Bobsledding Shoes","authors":"Seung-bum Park, Kyungdeuk Lee, Daewoong Kim, Jung-Hyeon Yoo, Jae-Hu Jung, Kyunghwan Park, Sungwon Park, Jin-Hoon Kim","doi":"10.5103/KJSB.2016.26.3.315","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.315","url":null,"abstract":"France won the gold medal in bobsleigh at the 1998 Nagano Winter Olympics. The finish times of this 6 km race varied within 0.1 second: France, in first place, had a time of 53.63 seconds, followed by Germany with 53.70 seconds, Great Britain with 53.71 seconds, and the United States with 53.73 seconds. At the 2014 Winter Olympics in Sochi, rankings were determined by combining the finish times from four runs, all of which varied within 0.1 seconds: Russia placed first, with a time of 3:40.60, followed by Latvia with 3:40.69, and the United States with 3:40.99. These results indicate that bobsleigh is one of the fastest winter sports, in which wins are determined by shortening the time spent on narrow ice tracks and achieved through extreme speeds and competition (Dabnichki, 2015). A bobsleigh run lasts approximately 60 seconds, and the sleigh should run along the ice track at a mean speed of 135 km/h for competitive speed and decreased completion time (Denny, 2011). This is closely associated with the postures, weights, and steering techniques of the players, as well as aerodynamic variables of the sleigh. Efforts have been made to improve these factors and ultimately shorten the time (Chowdhury, Loganathan, Alam & Moria, 2015; Ubbens, Dwight, Sciacchitano & Timmer, 2016). Recent studies focused on improving bobsleigh times found that shortening the start by 0.01 seconds could shorten overall lap time by 0.03 seconds, suggesting importance of the start (Dabnichki & Avital, 2006; Park, Kim & Park, 2015, Sabbioni, Melzi, Cheli & Braghin, 2016). In bobsleigh, starting involves teams sprinting approximately 30 m while pushing the 390 kg sleigh on a slippery surface. A strong propulsive force should be produced between the players' shoes and the ice surface in the starting area to decrease lap time and improve performance. Improvements in sports times have been associated with technological advancements in equipment. Bobsleigh shoes, along with the sleigh, helmets, and gloves, distribute the power of players onto the ice surface. Selection of appropriate shoes could act as a variable in improving the players' performance and times. In consideration of the various mechanical variables of each sport, forefoot bending angle has been modified in the general selection and development of athletic shoes. Forefoot bending angle in shoes is associated with ground reaction force and advancing force acceleration in terminal stance and pre-swing KJSB Korean Journal of Sport Biomechanics 2016; 26(3): 315-321 http://dx.doi.org/10.5103/KJSB.2016.26.3.315 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133148317","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 Effects of the Upright Body Type Exercise Program on Foot Plantar Pressure of Archers","authors":"Dong-Ku Kim, J. Lee","doi":"10.5103/KJSB.2016.26.3.285","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.285","url":null,"abstract":"This study is aimed to analyze how the upright body type exercise program, a spine stabilization exercise program, increases in upper limbs motility control of archers and affects foot plantar pressure of archers by stabilizing h d y balance in order to prove the effectiveness of upright body type exercise, and, on this basis, provide a new effective and efficient training program. To determine how the 12-week(3 times a week) upright body type exercise program affected plantar pressure of archers, a total of I 0 archers-3 men and 7 women-in B Metropolitan City who had more than 10 years of career in archery were sampled. The upright body type exercise program had positive effects on static and dynamic balance of foot plantar pressure by allowing archers to experience less body sway and physical imbalance in shooting and with closed eyes. So the program is expected to help archers correct their posture, become psychologically stable, and make better performance.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"50 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131324897","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 Vertical Alignment of Leg on the Knee Trajectory and Pedal Force during Pedaling","authors":"Daehyeok Kim, Jeongwoo Seo, S. Yang, D. Kang, Jin-Seung Choi, Jin-Hyun Kim, G. Tack","doi":"10.5103/KJSB.2016.26.3.303","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.303","url":null,"abstract":"Objective: This study evaluated the vertical and horizontal forces in the frontal plane acting on a pedal due to the vertical alignment of the lower limbs. Method: Seven male subjects (age: 25.3 ± 0.8 years, height: 175.4 ± 4.7 cm, weight: 74.7 ± 14.2 kg, foot size: 262.9 ± 7.6 mm) participated in two 2-minute cycle pedaling tests, with the same load and cadence (60 revolutions per minute) across all subjects. The subject``s saddle height was determined by the height when the knee was at 25° flexion when the pedal crank was at the 6 o``clock position (knee angle method). The horizontal force acting on the pedal, vertical force acting on the pedal in the frontal plane, ratio of the two forces, and knee range of motion in the frontal plane were calculated for four pedaling phases (phase 1: 330~30°, phase 2: 30~150°, phase 3: 150~210°, phase 4: 210~330°) and the complete pedaling cycle. Results: The range of motion of the knee in the frontal plane was decreased, and the ratio of vertical force to horizontal force and overall pedal force in the complete cycle were increased after vertical alignment. Conclusion: The ratio of vertical force to horizontal force in the frontal plane may be used as an injury prevention index of the lower limb.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"150 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115193335","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 Effects of Upper Limb, Trunk, and Pelvis Movements on Apkubi Momtong Baro Jireugi Velocity in Taekwondo","authors":"Sihyun Yoo","doi":"10.5103/KJSB.2016.26.3.273","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.273","url":null,"abstract":"Objective: The purpose of this study was to investigate effects of upper limb, trunk, and pelvis kinematic variables on the velocity of Apkubi Momtong Baro Jireugi in Taekwondo. Method: Twenty Taekwondo Poomsae athletes (age: 20.8 ± 2.2 years, height: 171.5 ± 7.0 cm, body weight: 66.2 ± 8.0 kg) participated in this study. The variables were upper limb velocity and acceleration; trunk angle, angular velocity, and angular acceleration; pelvis angle, angular velocity, and angular acceleration; and waist angle, angular velocity, and angular acceleration. Pearson's correlation coefficient was calculated for Jireugi velocity and kinematic variables; multiple regression analysis was performed to investigate influence on Jireugi velocity. Results: Angular trunk acceleration and linear upper arm punching acceleration had significant effects on Jireugi velocity ( p <.05). Conclusion: We affirmed that angular trunk acceleration and linear upper arm punching acceleration increase the Jireugi velocity.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128840389","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 Prolonged Running-Induced Fatigue on the Periodicity of Shank-Foot Segment Coupling and Free Torque","authors":"Jiseon Ryu","doi":"10.5103/KJSB.2016.26.3.257","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.3.257","url":null,"abstract":"Fatigue is defined as lassitude and weariness resulting from a bodily or mental endeavor, a state in which the force or sensitivity in cells, muscles, and organs is temporarily weakened after a prolonged activity or stimulus (Choi & Song, 2003). There are various causes of fatigue, and fatigue induced by exercise is a local phenomenon generated in contracted muscles, in which it is difficult to maintain muscular tension while muscular contraction continues (Choi & Song, 2003; Gibson & Edward, 1985). Fatigue caused by muscle movements such as exercise or physical labor is temporary; it is an acute condition that can be mitigated by rest or sleep (Choi & Song, 2003; McFarland, 1971). Fatigue caused by prolonged running is the main factor that disturbs the exercise by reducing the efficiency of the effort to continuously generate force (James, Dufek, & Bates, 1992; Ryu, 2004). Prolonged running that causes fatigue is a very effective sport that enhances bodily health; however, it can also cause injury and pain because of the physiological limitations of the human body (Elliot & Ackland, 1998). Fatigue due to exercise mainly occurs later during the workout and increases the possibility of injury by damaging muscular force, coordination, and attentiveness (Collins & Whittle, 1989; Ryu, 2016). Therefore, observing changes in the mechanical factors related to injury in the fatigued state due to prolonged running is necessary to predict and evaluate the risk of injury (Ryu, 2004). During bodily movements, the coupling of segments and joints is closely related to injury (Boyer, Silvernail, & Hamill, 2014; Hamill & Haddad, 2002; Ryu, 2004). Among the many couplings that occur during exercise, the coupling of foot inversion-eversion and shank internalexternal rotation is known to be an important motion in predicting the mechanism of potential injury (Nigg, Cole, & Nachbauer, 1993; Nigg, Khan, Fisher, & Stefanyshyuh, 1998; Ryu, 2004). Thus, analysis of the relative change in movement of the coupling in the fatigued state induced by prolonged running would provide quantitative data for clarifying the fatigue itself and the possibility of potential injury (Hamill & Haddad, 2002). Furthermore, investigation of the changes in relevant kinematic factors is not only important to determine the cause of potential injury during prolonged running but also necessary for the successful execution of the exercise. The shank is located proximally to the foot segment; therefore, it is easily exposed to a twist load due to the torque transfer caused in the foot segment, making it vulnerable to injuries such as stress fracture (Pohl, Hamill, & Davis, 2009). While running, the free torque to the vertical axis, which is generated by the frictional KJSB Korean Journal of Sport Biomechanics 2016; 26(3): 257-264 http://dx.doi.org/10.5103/KJSB.2016.26.3.257 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"34 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123486799","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}