• 대한지역사회영양학회지
• /
• 제22권5호
• /
• pp.413-425
• /
• 2017

Objectives: Accurate assessment of energy expenditure is important for estimation of energy requirements in athletic children. The objective of this study was to evaluate the accuracy of accelerometer for prediction of selected activities' energy expenditure and intensity in athletic elementary school children. Methods: The present study involved 31 soccer players (16 males and 15 females) from an elementary school (9-12 years). During the measurements, children performed eight selected activities while simultaneously wearing the accelerometer and carrying the portable indirect calorimeter. Five equations (Freedson/Trost, Treuth, Pate, Puyau, Mattocks) were assessed for the prediction of energy expenditure from accelerometer counts, while Evenson equation was added for prediction of activity intensity, making six equations in total. The accuracy of accelerometer for energy prediction was assessed by comparing measured and predicted values, using the paired t-test. The intensity classification accuracy was evaluated with kappa statistics and ROC-Curve. Results: For activities of lying down, television viewing and reading, Freedson/Trost, Treuth were accurate in predicting energy expenditure. Regarding Pate, it was accurate for vacuuming and slow treadmill walking energy prediction. Mattocks was accurate in treadmill running activities. Concerning activity intensity classification accuracy, Pate (kappa=0.72) had the best performance across the four intensities (sedentary, light, moderate, vigorous). In case of the sedentary activities, all equations had a good prediction accuracy, while with light activities and Vigorous activities, Pate had an excellent accuracy (ROC-AUC=0.91, 0.94). For Moderate activities, all equations showed a poor performance. Conclusions: In conclusion, none of the assessed equations was accurate in predicting energy expenditure across all assessed activities in athletic children. For activity intensity classification, Pate had the best prediction accuracy.

• 한국항해항만학회지
• /
• 제37권6호
• /
• pp.575-580
• /
• 2013

IMU(Inertial Measurement Unit)는 선박, 잠수함, 항공기 및 군용장비 응용분야에서 적용되어 자세 측정 영역에 주로 사용되고 있지만, 이런 IMU는 고가의 장비이기 때문에 특수 분야에서만 한정적으로 이용되어 왔다. 그러나 MEMS AHRS(MEMS : Micro Electro Mechanical System, AHRS : Attitude and Heading Reference System)의 현 기술 상황은 지능형 MEMS AHRS가 채택된 응용분야에서 가격이 높은 IMU를 대체 할 수 있는 수준에 이르고 있다. 본 논문에서는 자이로 센서, 가속도 센서, 지자기 센서를 사용한 AHRS를 이용하여 선박의 주요 운동 요소인 횡동요, 종동요, 선수동요 값을 측정할 수 있는 무선 선체 운동 측정 시스템을 개발하였다. 또한 AHRS 센서가 발생시키는 오차인 순간 가속도, 지자기의 영향 및 진동에 대응하기 위하여 칼만 필터링 기능이 탑재된 센서를 적용함으로서 최적의 성능을 실현하고자 하였다. 본 연구에서 구현한 AHRS 센서를 이용한 무선 선체 운동 측정 시스템을 이용하여 실선 실험을 실행하였으며, 선박의 제한적인 설치 상황에서도 편리하게 적용할 수 있을 것으로 보여진다. 향후 이 시스템이 선박에서 INS(Integrated Navigation System) 및 VDR(Voyage Data Recorder)과 같은 선박 장비와 호환되어 활용될 경우 항해 안전과 해양사고 분석에 유용하게 사용될 수 있을 것으로 판단된다.

• 응용통계연구
• /
• 제30권1호
• /
• pp.25-39
• /
• 2017

최근 경륜은 2015년도 기준, 5백만 명 이상의 많은 사람들이 참여하고 2조를 넘어선 매출을 발생시키는 대중적인 레저스포츠로서 자리 잡고 있다. 본 연구의 목적은 다양한 통계적 분석기법을 사용하여 경륜경기의 순위를 예측하고, 순위에 유의한 영향을 미치는 변수들을 파악하는 데에 있다. 다양한 Classification 방법과 Regression 방법들을 적용하여 순위예측모형을 만들고 비교분석하였다. 대부분의 모형에서 공통적으로 선택된 변수들을 살펴보면, 등급이 강급될수록, 종합득점이 높을수록 순위가 높아지며 반대로 등급이 승급될수록, 번호 4번을 부여받을수록 그리고 최근성적의 순위가 낮을수록 순위가 낮아지는 것을 알 수 있었다. 또한, 선수의 실력과 관련된 연속형 변수들을 각 경기별로 평균값을 빼서 보정한 자료와 원자료를 사용하여 모형을 적합시킨 결과 모든 모형에서 보정된 자료를 사용하였을 때 더 낮은 오분류율을 보였다. 마지막으로 분석에 사용하지 않은 최근 한 달 경기결과를 예측해서 베팅했을 때 모든 경우에 예측률은 높았지만 큰 이익을 거두지 못했는데 그 이유는 낮은 배당률을 가진 경기의 결과만을 잘 예측했기 때문이다.

• 한국운동역학회지
• /
• 제15권3호
• /
• pp.71-78
• /
• 2005

The purpose of this research was to conduct an analysis on the factors that determine the distance at the time of target swing based on the use of late hitting of outstanding college golfers to verify the difference between late hitting and the distance that target increases in regular swing and the distance. Then, this research conducts an analysis on the correlation between club head velocity, ball velocity, launch angle, back spin, meet ratio and distance that become kinematics variables at the time of target swing. To attain the above mentioned purpose, 25 outstanding college players with average experience and handicap of 6 years and 5, respectively, were targeted Comparative analysis on two swing that target increase in regular and the distance was conducted by used driver. When it pertained to two types of swing. analysis system comprised of an analytical software called the Science Eye of the Bridgestone and peripheries was used to define the relationship between variables of club head velocity, ball velocity, launch angle, back spin, meet ratio that become kinematics variables. As for the method of processing data pertaining to the factors that determine the distance, differences of distance by the type of swing was verified by using independent T-test that leveraged SPSS 120 statistics program. Moreover, level of correlation between variables that contribute to the increase in distance through relation of correlation, and analysis of tendencies was conducted to analyze tendency of non-distance to increase in accordance to the increase of each variable. Key results produced through this experiment are as follows: 1. Artificial late hitting for increased non-distance that targets skilled players had effect on increased the distance(p<. 05). 2 The drive distance is correlated with each measured variable that is positive correlation to ball velocity, club head velocity, meet ratio and relation of back spin and launch angle are negative correlation. ball velocity and club head velocity are very high correlated with drive distance(p<.01), back spin and distance are negative correlation(p<.01). 3. Among each measured variable increasing the club velocity is the most contribution, and ball velocity and meet ratio and the increasing launch angle and back spin is negative effect for increasing distance.

• 한국운동역학회지
• /
• 제20권4호
• /
• pp.395-406
• /
• 2010

The purpose of this study was to analyze the changes in kinematic and kinetic parameters of lower extremity joint according to rehabilitation period. Fourteen collegiate male athletes(age: $22.1{\pm}1.35$ years, height: $182.46{\pm}9.45cm$, weight: $88.63{\pm}9.25kg$) and fourteen collegiate athletes on functional ankle instability(age: $21.5{\pm}1.35$ years, height: $184.45{\pm}9.42cm$, weight: $92.85{\pm}10.85kg$) with the right leg as dominant were chosen. The subjects performed drop landing. The date were collected by using VICON with 8 camera to analyze kinematic variables and force platform to analyze kinetic variables. There are two approaches of this study, one is to compare between groups, the other is to find changes of lower extremity joint after rehabilitation. In comparison to the control group, FAI group showed more increased PF & Inversion at IC and decreased full ROM when drop landing. Regarding the peak force and loading rate, it resulted in higher PVGRF and loading. FAI group used more increased knee and hip ROM because of decreased ankle ROM to absorb the shock. And it used sagittal movement to stabilize. In terms of rehabilitation period, FAI group showed that landing patterns were changed and it increased total ankle excursion and used all lower extremity joint close to normal ankle. Regarding the peak force and loading rate, FAI group decreased PVGRF and loading rate. and also showed shock absorption using increased ankle movement. And COP variable showed that proprioception training increased stability during 8 weeks. The results of this study suggest that 8 weeks rehabilitation period is worthwhile to be considered as a way to improve neuromuscular control and to prevent sports injuries.

• 한국운동역학회지
• /
• 제17권3호
• /
• pp.197-207
• /
• 2007

It has been reported that Back-Tension played a significant role in archery (Lee & Bondit, 2005; Kim, 2007) but there are a few researches related Back-Tension in Korea recently. Therefore, the purpose of this study was to investigate archery back tension technique for the second ranked archer in the World and to find ways to improve performance. A subject(height: 185cm, mass: 82kg, years: 21yrs, careers: 12yrs) who is a number of national team and the second ranked archer in the World authorized by FITA (Federation Internationale de Trial Arc) was perticipated in this experiment. When shooting 60 shots($12{\times}5$), shooting motions were recorded with 7 infrared cameras and 2 ultrahigh-speed cameras. A QTM and an Auto Track were used to acquire raw data. The sampling rates of both cameras were 200 Hz. and 1000 Hz. respectively and data were filtered using a fourth order Butterworth low pass filtering with a cutoff-frequency of 30Hz. The parameters were calculated with Matlab6.5 and analyzed with SPSS11.0. After Pearson's correlations between 8 parameters were analyzed, 5 parameters from 13parameters that affected records were analyzed with multiple regression analysis (Enter order: x1, x2, x3, x4, x5). The results were as follows: 1. Comparing between parameters according to scores, the patterns of horizontal and vertical angular velocity(av.) of scapular relative angle was different between 8 score and 9 or 10 scores. 2. The correlations of parameters that affected records were a horizontal av.(x1, p=.032<.05) and a vertical av.(x3, p=.033<.05) of scapular from release to delivery in KB back-tension (anchoring-delivery). 3. The decision coefficients(R2) of above two parameters and three parameters selected by experts that may affect record, that is, an absolute trunk angle(x4) from in KKC back-tension (anchoring-release) and a horizontal relative scapular angle(x2) and an absolute trunk angle(x5) from release to delivery in KB back-tension were 7.7%(x1), 0.1%(x2), 8.5%(x3), 0.7%(x4) and 0.9%(x5) in sequence. 4. The multiple regression equation was a y= -1.16E-2 x1 + 0.109 x2 + 3.437E-2 x3 + 6.139E-2 x4 + 0.117 x5 + 3.420 In conclusion, a total contribution was low, that is, R2(17.9%) suggested that on the one hand, Lim's motion may not depend on a certain factor because his postural factors affected shooting motion are some stable on the other hand, unknown factors may exist(e.g. psychological, physiological factors etc.). Further study of EMG patterns of muscles and anatomic consideration related to shoulder girdle and scapular bones may help to identify mechanism of Back-Tension.

• 한국운동역학회지
• /
• 제17권3호
• /
• pp.31-39
• /
• 2007

The purpose of this study was to observe the kinematic pattern of elite women 100m hurdler race from start to finish and analyze how the change of horizontal velocity makes an influence on the athletes' performance. The analysis was based on the performance of Korean elite 100m hurdler A and international elite hurdlers B and C. Following results were drawn from the analyzation of elite 100m hurdlers' technical characteristics; During the race, hurdler A made more than 8 m/s of horizontal velocity at the 3rd, 4th, 6th, and the 7th hurdle. The horizontal velocity peaked at the 4th hurdle with 8.23 m/s. On the other hand, hurdler B and hurdler C maintained more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. Hurdler B's fastest horizontal velocity was 8.67 m/s from the 6th to the 7th hurdle and hurdler C's fastest horizontal velocity was 8.85 m/s from the 5th to the 8th hurdle. From the start line to the 3rd hurdle, the times achieved by hurdlers A, B, and C were 4.90 sec, 4.65 sec, and 4.52 sec. In the middle of the race, which is from the 4th hurdle to the 7th hurdle, hurdlers A, B, and C ran in 9.10 sec, 8.60 sec, and 8.38 sec. And the latter part of the race to the 10th hurdle, the times hurdlers A, B, and C hit were 12.32 sec, 11.66 sec, and 11.32 sec. To the finish line, it took 1.15 sec for hurdler A, 1.1 sec for B, and 1.06 sec for C. Hence, to set the record of sub-13 sec, hurdler A should improve her acceleration from the start line to the 1st hurdle with the speed more than 5.4 m/s and should maintain more than 8 m/s of horizontal velocity from the 2nd hurdle through the 10th hurdle. In addition, hurdler A should improve her speed endurance to minimize the deceleration of horizontal velocity from the 4th hurdle to the final hurdle. If hurdler A could shorten 0.05 sec of time in each hurdle section, she would be able to set the record under 13 seconds.

• The Journal of Korean Physical Therapy
• /
• 제23권1호
• /
• pp.21-28
• /
• 2011

Purpose: The aim of this study was to investigate correlations between the Functional Movement Screen (FMS), pain, and performance ability in professional fencing players. Methods: Fifty-six athletes participated in this study. The pain group included those who had a score on a pain-related Visual Analogue Scale (VAS) of ${\geq}$20 and an Oswestry Disability Index (ODI) score ${\geq}$10). In the non-pain group, these scores were: VAS(<20), ODI(<10). The VAS and ODI were used to measure pain throughout the study. Performance ability included motor function of the lower extremities (as assessed by a Modified Functional Index Questionnaire, MFIQ), dynamic balance (Balance system, BS and Posture med, PM), flexor and extensor muscle strength of the lumbar region was recorded as maximal isometric strength. Results: Among athletes who had pain, 5 of 15(33.33%) showed impaired functional movement. Conversely, only 2 of 41(4.88%) of those who had no pain showed such impairment (FMS ${\leq}$14score). The athletes who had pain and who had an FMS score above 14 (10/56; 17.86%) showed a significantly higher score for extensor muscle strength of the lumbar compared with those with pain and an FMS score below 14 (5/56; 8.93%) were significant correlations between the FMS and pain (r=-0.40 to -0.42, p<0.01), the MFIQ (r=-0.33, p<0.05), dynamic balance (r=-0.27 to -0.40, p<0.05-0.01), muscle strength of the lumbar (r=0.27 to 0.29, p<0.05). Stepwise multiple regression analysis showed that the dynamic balance score (${\beta}{\beta}$=-0.41) had slightly more power in predicting FMS score than pain, motor function of lower extremity, or muscle strength. Conclusion: The FMS was significantly associated with values of pain, motor function of the lower extremities, dynamic balance, and muscle strength of the lumbar. However the FMS appears to lack relevance and reasonable evidence to suggest that it is an acceptable measurement tool for functional movement analysis.

• 동의생리병리학회지
• /
• 제20권5호
• /
• pp.1254-1260
• /
• 2006

The purpose of this study was to the Pre-Post submaximal exercise for analyze the Blood Lactate, LDH(Lactate Dehydrogenase) and Glucose in the runners. The subjects were 12 volunteers 6 sprinters and 6 distance runners who agreed to intention of this study. Subjects peformed until possible all-out trials. Blood samples were taken from a Ante cubital vein Pre-Post exercise and every rest 5min during the all-out trial. The results obtained were summarized as follow; 1) Blood Lactate of Pre-Post exercise in treadmill test showed no significant difference between sprinters and distance runners, but showed significant in sprinters and distance respectively. 2) Serum LDH of Pre-Post exercise in treadmill test showed no significant difference between sprinters and distance runners, and that showed no significant in sprinters and distance respectively. 3) Blood Glucose of Pre-Post exercise in treadmill test showed no significant difference between sprinters and distance runners, and showed no significant in distance, but showed significant in sprinters. These data indicate first that the value of 4mmol/${\ell}$, commonly referred to as OBLA(Onset of Blood Lactate),may often underestimate the upper limit of tolerance to lactate during a maximal endurance peformance test until all-out. second, our date suggested that the sprinters exercise decreases serum LDH activities and the distance increases serum LDH activities. therefore serum LDH concentration changed following a different exercise. Third. for the concentration of the glucose in blood the sprinters was show to be higher. However it needs more studies to find out the relationship between this result and the fitness factor. therefor, since the runners has an intermittent characteristic which includes a frequent momentary change, it needs the fitness training that being consisted of various training. in the training method, it needs the training process which is from the whole fitness to specific fitness to improve general physical ability.

• 정보처리학회논문지D
• /
• 제16D권1호
• /
• pp.133-138
• /
• 2009

이 논문에서는 2018 평창 동계올림픽 개최를 위한 사전 준비 및 지역 전략 산업 육성정책의 일환으로 추진 중인 강원도의 u-Sports 사업의 하나로 강원도 용평 스키장에 구축된 무선 구간기록 측정 시스템에 적용된 기술과 그 성과를 소개한다. 기록 측정이 필요한 슬로프 구간의 진입점과 진출점에 각각 레이저 센서를 설치하고 각각의 레이저 센서를 센서 노드와 유선으로 연결하여 스키 선수가 해당 구간에 진입하거나 해당 구간을 빠져나가는 순간 센서 노드는 이를 감지하도록 하였다. 각각의 센서 노드는 또한 모뎀을 통하여 CDMA 망에 연결되어 있어서 망을 통하여 NTP 서버로부터 표준 시간을 수신한다. 센서 노드는 분해능이 높은 내부 타이머를 CDMA 망을 통하여 수신한 표준 시간에 동기를 맞추는 NTP 알고리즘으로 기록 측정에 필요한 최소 10 ms의 분해능을 확보하도록 하였다. 각각의 센서 노드에서 측정된 시간 정보는 CDMA 망을 통하여 중앙 관제 센터에 전송된다. 이 논문에서 소개한 무선 구간 기록 측정 시스템은 고가의 장비를 필요로 하지 않으므로 비용이 저렴하며 이 시스템을 사용하면 기존의 수동 측정 방식을 사용한 경우보다 더 간편하게 중앙 관제 센터에서 구간별 기록 정보를 획득할 수 있다는 장점이 있다.