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1 Association of Underweight and Hand Grip Strength with the Risk of All-cause Mortality in Older Adults
Min-jun Kim ; Tae-woong Oh Vol.34, No.4, pp.547-557 https://doi.org/10.24985/kjss.2023.34.4.547
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Abstract

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.

2 The Effects of Injury Experience in Lower Extremities on Joint Range of Motion, Muscle Extensibility, and Dynamic Stability in Elite Volleyball Players
Taegyu Kim ; Eunkuk Kim ; Du Ruofei ; Hokyung Choi Vol.34, No.4, pp.558-568 https://doi.org/10.24985/kjss.2023.34.4.558
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Abstract

PURPOSE This study investigates the impact of injury experience on ankle dorsiflexion, quadriceps extensibility, and dynamic stability in elite adolescent and adult volleyball players. METHODS A total of 485 players (adolescents=337, adults=115) reported lower extremities injuries, with measurements taken for ankle dorsiflexion and quadriceps extensibility using the weight- bearing lunge test and Ely’s test, respectively. The Y-balance test was used for dynamic stability. Measurements were conducted on the injured leg of players with knee and/or ankle injuries and the dominant leg of healthy players. Four groups were classified based on injury experience, and comparisons were made between both legs. Additionally, the variables of adolescent players were compared to those of adults. RESULTS Adolescent players with knee injuries exhibited a larger difference in ankle dorsiflexion between both legs, while adult players with ankle injuries demonstrated an asymmetry of ankle dorsiflexion. Regardless of age, players with knee or ankle injuries displayed lower dynamic stability compared to healthy players. Notably, adults with knee injuries showed a larger difference in dynamic stability between both legs. CONCLUSIONS To prevent and rehabilitate volleyball-related injuries, comprehensive injury risk factors, including age, should be managed in the injury prevention strategies.

3 Effect of Different Resistance Training Structures on Basic Physical Fitness and Isokinetic Muscular Contraction
Peng Liu ; Yeong-Jik Kim ; Tae-Beom Seo Vol.34, No.4, pp.569-578 https://doi.org/10.24985/kjss.2023.34.4.569
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PURPOSE This study aimed to investigate the effects of different resistance training structures on basic physical fitness, 1-repetition maximum (1RM), and isokinetic shoulder and knee muscle functions in male college students. METHODS Forty college students were divided into four groups: control group (CG, n=10), compound set training group (CSG, n=10), pyramid set training group (PSG, n=10), and superset training group (SSG, n=10). Excluding CG, each group performed a different resistance exercise method at an intensity of 60~80% 1RM for 60~90 min, three times a week for eight weeks. To compare the effects of resistance training structures, we confirmed body composition, basic physical fitness, 1RM, as well as isokinetic shoulder and knee functions. RESULTS Results indicated that the PSG exhibited the most significant improvement in relative peak torque in isokinetic shoulder and knee testing compared to the other groups. Additionally, all exercise groups positively affected back strength, 40m sprint, and 1RM compared to the CG, although no significant differences were observed among exercise groups. CONCLUSIONS The findings suggest scientific evidence supporting the effectiveness of pyramidal resistance training in improving isokinetic shoulder and knee muscle functions in male college students.

4 Effects of Body Mass Index on Ankle Joint Muscle Function and Dynamic Proprioceptive Control
Ji-Hoon Cho ; Seung-Taek Lim ; Eunjae Lee Vol.34, No.4, pp.579-587 https://doi.org/10.24985/kjss.2023.34.4.579
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PURPOSE Increased body mass index (BMI) increases ankle instability and adversely affects human movement. This study aims to compare and analyze the muscle function and proprioception of the ankle joint based on Body Mass Index (BMI) to determine potential differences. METHODS Twenty-eight healthy male and female college students were categorized into overweight (≥ BMI 23) and normal (< BMI 23) groups. Measurements included BMI, isokinetic strength of dorsiflexion, plantarflexion, eversion, inversion, ankle joint range of motion, and ankle joint proprioception. RESULTS In dorsiflexion, right 30°/sec (p=.035), left 30°/sec (p=.009) and right 120°/sec (p=.011); in plantarflexion, left 30°/sec (p<.001), right 120°/sec (p=.007) and left 120°/sec (p=.006) in ankle inversion, left 30°/sec (p=.001), right 120°/sec (p=.021) and left 120°/sec (p=.007), left 30°/sec (p=.014), 120°/sec (p=.001) in ankle inversion-eversion ratio, right (p=.003) and left (p=.003) in ankle joint range of motion, right (p<.001) and left (p=.022) in total proprioception, and left (p<.001) in left-right proprioception were significantly different between the normal and overweight groups. CONCLUSIONS It was found that the overweight group had lower muscle strength, joint range of motion, and proprioceptive control function of the ankle joint than the normal group according to BMI. Therefore, exercise programs should be provided to strengthen the periarticular muscles involved in ankle movement, such as the tibialis anterior, soleus, and peroneus longus, and to control dynamic proprioception to prevent ankle injuries and function of the ankle joint according to BMI.

5 Impact of Injury Prevention Video Feedback on Biomechanical Variables of the Knee Joint during Cutting Maneuver
Mi-so Lee ; Sung-min Kim ; Jeheon Moon Vol.34, No.4, pp.588-595 https://doi.org/10.24985/kjss.2023.34.4.588
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PURPOSE This study aims to analyze the effects of injury prevention video feedback on kinetic variables of the knee joint during the cutting maneuver. METHODS Twenty-eight healthy men participated and motion and force data were collected using infrared cameras, a force plate, and a Witty timing system. Paired t-tests were employed for data evaluation using the SPSS 26.0 program. RESULTS Results showed increased abduction and lateral rotation angles of the knee joint at the lower height of the center of mass (COM) (p<. 05). The lateral rotation of the knee joint decreased at initial ground contact (p<.05). Flexion angular velocity increased at initial ground contact after video feedback (p<.05) and decreased at the lower height of COM (p<.05). Abduction angular velocity decreased at the lower height of COM (p<.05), and internal rotation angular velocity was increased on the initial ground contact (p<.05). Maximum ground reaction force for anterior-posterior and medial-lateral directions increased after video feedback (p<.05). Flexion and internal rotation moments increased, and adduction moment also increased (p<.05). CONCLUSIONS In conclusion , video feedback effectively reduced knee load during the cutting maneuver, contributing to injury prevention for the knee joint.

6 A Qualitative Study on the Perceptual Changes of [Goal Kicking Women] Male Viewers Regarding Women’s Football
Hwayeoung Lee ; Eunah Hong Vol.34, No.4, pp.596-606 https://doi.org/10.24985/kjss.2023.34.4.596
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PURPOSE This study aims to identify how the [Goal Kicking Women] TV program has changed the perceptions of male viewers on women’s football. METHODS Using a qualitative research design, semi-structured interviews were conducted with 8 male viewers who are in their 50s. Thematic analysis was used to draw implications from the interviews. RESULTS Results show that having watched [Goal Kicking Women], 1) participants have become more familiarized with women playing football; 2) participants’ initial stereotype about women’s alleged inferiority in football has changed, as the performance of female stars in the program, who did not have any experience playing football, improved; and 3) the genuine passion that female stars showed for football made participants think that women’s football was just as good as men’s. CONCLUSIONS This study provides practical and academic implications, as it identifies men’s perceptions on women’s football and analyzes the influence of [Goal Kicking Women]. To conclude, establishing a foundation for planning and implementing effective policies to promote women’s football in South Korea is recommended.

7 Trends in Psychological Experiences of Athletes by Period in the Long Jump Competition
Deok-Hyeon Kim ; Young-Kil Yun Vol.34, No.4, pp.607-617 https://doi.org/10.24985/kjss.2023.34.4.607
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PURPOSE This study explored psychological experiences in long jump competitions and examined the continuity of psychological experiences over time. METHODS A total of 28 adult long jumpers, 18 men and 10 women, were provided data through in-depth interviews. Data on psychological experiences were extraced through inductive content analysis, while continuity by period was analyzed by calculating the response frequency ratio using Excel. RESULTS First, the psychological experience in the long jump competition was categorized as fundamental, competition intelligence, emotional control, and communication capacity experience. Second, in long jump competitions, results showed that jumpers experienced mixed feelings of anxiety and pressure, self-confidence, and concentration in the first period; peer communication and analysis thinking were necessary in the second period; practical intelligence and pressure control were important in the third period; learning ability and creativity were crucial in the fourth period; learning ability and coach communication were applied in the fifth period; and fighting spirit and creativity were present in the sixth period. Third, the psychological experience of long jumpers by period, basicphysical strength was maintained; competition intelligence increased in the second and fourth periods; communication skills increased until the fifth period, and decreased after; while emotional control decreased. This reflects the contextual changes over time andthe change in competition records owing to that. CONCLUSIONS In the long jump competition, psychological experience changes by period and affects competition records. This study will contribute to further understanding of psychological continuity.

8 When Does Losing Lead to Winning? An Empirical Investigation on the Korean Professional Basketball League
Sang Hyun Lee ; JeongJun Moon ; Philsoo Kim Vol.34, No.4, pp.618-627 https://doi.org/10.24985/kjss.2023.34.4.618
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PURPOSE This study was conducted to refine and verify the argument by Berger & Pope (2011). Based on expectancy theory, we expected that the existence or type of regression discontinuity could vary depending on the situation and time in Korean Professional Basketball League. METHODS We conducted a regression discontinuity design using the R 4.3.1 package on the data of 4,531 games played during the 17 regular seasons (2006–2007 and 2022–2023) of the Korean Basketball League. We divided the sample into top-tier teams (1st and 2nd place) and mid to lower-tier teams (3rd to 10th place). Furthermore, we segregated the sample into the early phase of the regular season (1st and 2nd round) and mid to final phase of the regular season (3rd to 6th round). RESULTS First, a discontinuity of the regression was found after the third quarter. Second, the regression discontinuity appeared differently depending on the performance level. More specifically, discontinuity effects did not appear among the top teams whereas the regression discontinuity effects were identified among mid to lower-tier team samples. Third, the regression discontinuity appeared differently depending on the time point of the regular season (round). A discontinuity of regression line appears from the 3rd to 6th rounds in the Korean Professional Basketball League. CONCLUSIONS This research provides theoretical and practical contributions by systematically exploring that the probability of winning can vary even with the same score difference depending on the time point and situations perceived by the players.

9 Cultural Changes at Korean Tennis Clubs Due to COVID-19 : Focusing on the Accepted Culture
Min-Cheul Kim ; Hanbeom Kim Vol.34, No.4, pp.628-637 https://doi.org/10.24985/kjss.2023.34.4.628
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PURPOSE This study examined the cultural experiences of tennis club members that have changed due to COVID-19, specifically emphasizing the accepted culture within these clubs. METHODS Seven tennis club members, with over five years of experience, active participation in two or more clubs, and a history of active participation, were interviewed using in-depth interviews and a semi-structured questionnaire. RESULTS Firstly, the tennis club members accepted the “no contact” culture that has emerged since COVID-19. Secondly, social distancing made getting together in large groups difficult, and tennis club activities became more limited. This has led to weakening the tennis club community, which is different from what we have seen before. Lastly, the growing interest in non-traditional content has led to an increase in participants enjoying tennis through social media. The information and experiences gained through social media have changed the perception of coaching. CONCLUSIONS The cultures that tennis players have adopted due to COVID-19 are expected to continue in the future. The findings from this study may provide evidence for understanding the changing culture of sports in the future.

10 A Bayesian Network Approach to Infer Causality of Sports Spectators' Eco-Friendly Behavioral Intentions
Soowoong Hwang ; Jiho Lee ; Dojin Jang Vol.34, No.4, pp.638-650 https://doi.org/10.24985/kjss.2023.34.4.638
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PURPOSE This study explores the factors influencing eco-friendly behavioral intentions during sports spectating and infers the causal structure linking each variable to eco-friendly behavioral intentions. METHODS A total of 364 sports fans participated in the survey that collected data on Knowledge of Climate Change (KCC), Awareness of Climate Change (ACC), Attitude of Climate Change (ATT), Subjective Norm of Climate Change (SN), Perceived Behavior Control of Climate Change (PBC), and Behavioral intention to Reduce Single-Use Plastic (INT) during sports spectating. The validity of the measurement was examined through confirmatory factor analysis. Based on the validated data, latent variables’ average scores were reconstructed as input variables for the Bayesian Network, along with demographic characteristics. RESULTS The results of Bayesian network learning indicated that ACC, ATT, SN, and PBC variables directly influence INT. ACC affects ATT and SN, while ACC is influenced by KCC and sex. Conversely, PBC influenced INT but showed no association with the other input variables. SN was found to have the greatest impact on INT during sports spectating, while the influence of PBC was relatively low. CONCLUSIONS The causal structure inferred in the current study using Bayesian network learning provides insights into the previously underexplored relationship structure explaining eco-friendly behavioral intentions of sports fans in the field of sports science. The findings of this study can serve as empirical evidence for sports-related organizations to develop strategies and decision-making processes to promote sustainable sports spectatorship.

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