PURPOSE This study investigated weight-class-related strength parameters during pulling performance in the ssireum. METHODS Elite ssireum athletes participated, 24 divided into four weight classes of six athletes each. They performed a pulling task while gripping a tube fixed to a three-axes load cell sensor, standing on force plate platforms. The test involved 30 repetitions at maximal force with the legs bent, the ssireum’s typical posture. Maximal force (Fmax), time to maximal force (TFmax), time difference between maximal forces (TDmax), and horizontal and vertical angles at maximal force (HAmax and VAmax, respectively) were analyzed from the load cell sensors. Ground reaction force (GRF) was collected, including peak force along the three axes, the resultant force, and the center of pressure (COP). One-way ANOVA tests were conducted to compare among weight classes (α=.05). RESULTS Fmax measured by load cell showed significant difference between classes (p<.05), indicating that the second weight group (Geumgang class) generated more pulling force than the heavier classes. In GRF results, lightweight classes demonstrated larger COP difference between the left and right plates. Specifically, the Geumgang class showed more movement in the anterior-posterior (AP) direction on the left plate. The peak GRF in the right plate of the AP (p<.001) and ML (p<.05) directions showed significant differences between lighter and heavier weight classes. CONCLUSIONS The Geumgang class generated greater pulling force, and the lighter classes demonstrated more leg contribution. Force generation did not solely depend on body mass; instead, lighter athletes often relied on the lower limbs to compensate for their limitations, a strategy commonly observed in competitions.
PURPOSE This study aimed to develop the theory of child abuse of children with disabilities in Adapted Physical Education (APE). METHODS A grounded theory study was conducted based on a constructivist approach. Data were collected via in-depth interviews. Participants were 20 instructors selected based on theoretical sampling. The collected data were analyzed in the order of open coding, axial coding, and selective coding. RESULTS First, the direct causal conditions of abuse of children with disabilities in APE were the instructors’ and guardians’ distorted perception towards the disabled children along with the individual vulnerability of children with developmental disabilities. Second, the contextual conditions that form the background of the abuse of children with disabilities in APE included the burden of the instructor due to the unjust demands of the guardian of the child, the growth background of the instructor, and the repressive atmosphere of APE. Third, abuse of children with disabilities can be divided into three types: ‘active abuse’ based on the instructor’s distorted viewpoint of the child with a developmental disability, ‘passive abuse’ due to the unjust demands of the guardian, and ‘passive abuse’ due to the structural problems in the APE field. Fourth, the abuse of children with disabilities in APE, which can be distinguished by different characteristics, affects the instructor’s inner conflict and self-reflection. CONCLUSIONS This study approached the phenomenon of abuse of children with disabilities in Korean adapted physical education as a grounded theory, and the theory generated is expected to contribute to the establishment of strategies necessary to design adapted physical education in keeping with human rights.
PURPOSE This study aimed to characterize the kinematic variables of stair climbing in adult women by analyzing the effects of varying heel heights on their climbing behavior. METHODS A total of 24 adult women (age: 22.08±1.28years; height: 160.43±4.30cm; weight: 54.10±6.39kg) participated in this study. All subjects wore the same type of high heels with heights of 1cm, 5cm, and 7cm while performing stair climbing on stairs measuring 18cm in height. Ten infrared cameras (200Hz) and ground reaction force sensors (1000Hz) were set up on the stairs, along with an 8-channel electromyography system (1000Hz) to analyze the maximum moments at each joint and the muscle activation during stair climbing. Data were analyzed using IBM SPSS Statistics version 27.0 (IBM., USA). All variables underwent the Shapiro–Wilk normality test, with repeated measure analysis of variance or the Friedman test applied based on the results. Post hoc tests were conducted using the LSD test or Wilcoxon signed-rank test. RESULTS Our study found four key findings. First, a significant decrease in maximum dorsiflexion, plantarflexion, inversion, and adduction moments of the ankle joint was observed with increasing heel height. Second, the maximum extension, adduction, and external rotation moments of the knee joint significantly decreased as heel height increased, while the maximum abduction and internal rotation moments significantly increased. Third, the maximum flexion, extension, and abduction moments of the hip joint significantly increased with higher heel heights. Fourth, muscle activity of the rectus femoris, vastus medialis, vastus lateralis, semitendinosus, and gastrocnemius decreased with increasing heel height compared to walking; however, muscle activity in the tensor fasciae latae increased. CONCLUSIONS The results of this study suggest that as heel height increases, the risk of injury may rise due to limited ankle use and increased moments in the knee and hip joints, potentially leading to muscle strength imbalances in adult women, particularly through the overuse of specific muscles.
PURPOSE This study analyzed the difference in lower extremity joint angle and shock absorption patterns at the point of maximum ground reaction force during single-leg drop landing with or without anterior cruciate ligament reconstruction (ACLR). METHODS Forty adult males were recruited for this study, with 19 in the ACLR group (age: 20.52±1.43years, height: 179.26±5.18cm, weight: 74.91±6.29kg) and 21 in the control group (age: 21.42±1.61years, height: 174.97±6.83cm, weight: 69.27±7.56kg). Participants performed single-leg landings on a 30cm tall box. An independent sample t-test was used to analyze the difference in kinetics variables at the point of maximum ground reaction force upon landing, with significance set at p=0.05. RESULTS The lower limb joint angle showed significant differences in hip flexion, hip abduction, knee flexion, and knee valgus (p<0.05) between groups. There was no significant difference between the groups in terms of the results of kinetics variables during single-leg landing (maximum ground reaction force, lower extremity stiffness, and shock absorption time). CONCLUSIONS The ACLR group showed a clear difference in kinematics compared to the control group, but no significant difference in kinetic results was found. The two groups compensated for the same impact with different movements, though movements in the ACLR group may increase the risk of ACL re-injury. Those with ACLR should strive to reduce the risk of re-injury by training to use correct movements.
PURPOSE This study sought to establish obesity diagnosis criteria by using the Body Volume Index (BVI) by body part extracted through 3D BodyScanner. METHODS The body fat percentage was measured using Dual Energy X-ray Absorptiometer (DEXA) for 225 participants (male = 119, female = 106), and BVI for eight body parts was measured using 3D BodyScanner. Independent t-test and Receiver Operating Characteristic (ROC) analysis were conducted. ROC analysis calculated the Area Under the Curve (AUC), and the optimal cut-point by Youden's J index. Sensitivity, Specificity, Accuracy, Balanced Classification Rate (BCR), and F1-score (harmonic mean of recall and precision) values were calculated to verify the validity of the optimal cut-point. RESULTS A statistically significant difference was observed in BVI by body part according to whether obesity was present for both men and women, and the obese group higher than the normal group. The optimal cut-point for each body part to diagnose obesity was 7.96 for shoulder, 9.79 for chest, 7.15 for upper abdominal, 7.71 for lower abdominal, 14.89 for total abdominal, 9.79 for thigh, 5.70 for calf, and 74.96 for total body volume in men. In case of women, this was 6.04 for shoulder, 9.82 for chest, 4.96 for upper abdominal, 6.23 for lower abdominal, 11.63 for total abdominal, 8.88 for thigh, 4.05 for calf, and 58.15 for total body volume, and the accuracy was 0.6~0.9. CONCLUSIONS BVI is a useful indicator for diagnosing obesity. However, this can be applicable only to Asian adults since there may be differences depending on race or age.
PURPOSE This study conducted a longitudinal analysis of physical activity levels and characteristics of middle-school boys and girls over a three-year period before and after the COVID-19 pandemic. METHODS This study used a sequential mixed-methods research design. In the quantitative study; three-dimensional accelerometers were used to measure weekly physical activity and sedentary time over three years (2019, 2020, and 2021) among 33 middle-school boys and girls, and the data were analyzed using repeated measures analysis of variance. In the qualitative study, data were collected and analyzed through focus group interviews with five participants. RESULTS The quantitative study indicated a significant increase in sedentary behavior and significant decrease in low-intensity activity and MVPA during the first year of the COVID-19 pandemic. In the second year of the pandemic, no significant difference was observed in sedentary behavior, low-intensity activity, and MVPA compared to the data collected in the first year. During the pandemic’s first year, qualitative study identified the following physical activity problems: “lockdowns,” “sedentarization of leisure,” and “reduced structured physical activity.” The following reasons were identified for the lack of improvement in physical activity during the second year: “intensified sedentary lifestyle habits,” “weak social networks,” and “lack of energy to exercise.” CONCLUSIONS The COVID-19 pandemic has led to a significant decrease in physical activity and a significant increase in sedentary behavior among middle-school students in South Korea, and even as the environments for physical activity have recovered, the physical activity problems of the early stages of the pandemic have not improved.
PURPOSE This study investigated the impact of underweight and hand grip strength (HGS) levels on the risk of all-cause mortality in older adults. METHODS Data from the 2006 baseline and 2020 follow-up assessments of the Korean Longitudinal Study of Aging (KLoSA), involving 3,009 older Koreans (≥65 years) were used in the study. Participants were categorized based on body mass index (BMI) as underweight, normal, overweight, or obese and grouped according to the Asian Working Group Sarcopenia criteria into high or low HGS. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% confidence interval (CI) of all-cause mortality according to BMI and HGS categories. RESULTS During the 11.3±4.0 years follow-up period, 1,334 deaths from all causes occurred. The risk of death by BMI and HGS level was analyzed. The results showed that the risk of death in the overweight and high HGS group (HR=0.773, p=.016) was significantly lower than that in the normal weight & high HGS group (HR=1). In comparison, the risk of death in the underweight & low HGS group (HR=1.930, p<.001) and the normal weight & high HGS group (HR=1.225, p=.014) were significantly higher than normal weight & high HGS. However, the risk of death in the underweight and high HGS group showed no significant difference compared to the normal weight and high HGS group. CONCLUSIONS The current findings suggest that improving muscle strength through regular exercise may be important in preventing the risk of all-cause mortality due to being underweight.
PURPOSE This study aimed to examine the effects of motion analysis and image training using self-modeling with visual cues on the skill performance, imagery, and sports confidence of adolescent female soccer players. METHODS The participants were elite soccer players from two girls’ high school soccer teams divided into an experimental group (D girls’ high school, n=16) and a control group (I girls’ high school, n=13). The experimental group underwent motion analysis and image training when performing penalty kicks, short kicks, and long kicks using self-modeling with visual cues, while the control group underwent training using self-modeling videos without visual cues. Before and after the training, the evaluation score was calculated according to kick performance, and the imagery and sports confidence factors were measured. For the statistical analysis of all collected data, descriptive statistics, the Friedman test, the Mann-Whitney U test, and two-way repeated-measures analysis of variance were used. RESULTS First, on the motion analysis using self-modeling with visual cues, the experimental group’s penalty kick and short kick scores were improved and differed significantly, but no significant change was noted in long kick score. Second, as a result of image training using self-modeling with visual cues, all visual, kinesthetic, mood, and controllability factors of the experimental group improved except for the auditory factor, and the interaction effect was confirmed. In addition, the stated sports confidence of the experimental group was improved and the interaction effect confirmed. CONCLUSIONS The analysis of kick motion using self-modeling with visual cues was effective for the penalty kicks and short kicks of adolescent female soccer players. Moreover, this study confirmed that the analysis of kick motion improved the visual, kinesthetic, mood, and controllability sub-factors of imagery and significantly affected the players’ stated sports confidence.
PURPOSE The purpose of this study was to analyze the level and characteristics of physical activity (sedentary, light, and MVPA) of high school students according to physical education (PE) class (DWPE: days with PE class, DNPE: days with no PE class) and sex. METHODS Data were collected on 147 students (65 male and 82 female) from four high schools in Seoul city, and physical activity was measured using a three-dimensional accelerometer. The collected physical activity data were input into SPSS 25.0, and the descriptive analysis and two-way ANOVA according to PE class and sex were performed. RESULTS The descriptive statistical analysis showed that 31% (40.7% male and 23.4% female) of participants met the recommended physical activity durations (MVPA of 60 min/day). In the two-way ANOVA, sedentary activity, light activity, and MVPA showed statistically significant main and interaction effects according to PE class and sex. According to the results of the interaction effect analysis, the gap in physical activity between DWPE and DNPE was large in male students. For male students, light activity and MVPA significantly increased on the day of the PE class, and sedentary activity significantly decreased. However, for female students, DWPE and DNPE did not differ significantly in all levels of physical activity. CONCLUSIONS In conclusion, the level of physical activity of Korean high school students was relatively low, and the effect of daily-life physical activity in the PE class was limited to male students. Accordingly, an alternative should be introduced to increase the physical activity of female high-school students through PE classes.
PURPOSE For student-athletes to be able to successfully dedicate themselves to training and competition, the following key factors play an important role: The coach, team climate, and individual motivational characteristics. To test this hypothesis, the structural relationships between having a perceived autonomy support, a caring climate, basic psychological needs, and sport commitment were analyzed. METHODS Participants were 297 high school athletes registered with the Korea Olympic Committee (203 males, 94 females, Mage=17.88 years). Data were collected using sports climate questionnaires for autonomy support, caring climate scale, basic psychological needs scale, and sport commitment measurement. The collected data were analyzed using descriptive statistics, correlation analysis, and structural equation modeling. RESULTS The model’s fitness was indicated by x2/df=2.797 (x2=106.288, df=38), CFI=.977, TLI=.967, RMSEA=.078 (90% CI=.061, .096). Examining the various path coefficients revealed that coach autonomy support had a positive effect on the athlete’s caring climate, basic psychological needs, and sport commitment. The caring climate had a significant effect on basic psychological needs, but did not have a statistically significant effect on sport commitment. Finally, basic psychological needs had a positive effect on sport commitment. CONCLUSIONS Coach autonomy support fosters a caring climate, and athletes who are able to perceive this are able to dedicate themselves to their sport since their basic physiological needs are met. Therefore, coaches should use appropriate coaching strategies to enhance athletes' autonomy and foster a caring climate, as both are essential factors for meeting athletes' psychological needs and promoting sport commitment.
