PURPOSE This study analyzed the effect of dynamic lumbar kyphosis on the biomechnical factors affecting the lumbar joints during deep squats. METHODS Thirty adults in their 20s who had experienced weight training for more than one year participated in this study (age: 23.4±3.5years old, height: 175.3±4.3cm, weight: 75.8±6.5kg, squat single repetition maximum (1RM) weight: 115.3±19.5kg). Under both restricted dynamic lumbar kyphosis (RDLK) and dynamic lumbar kyphosis (DLK), subjects completed one repetition of deep squats at a load of 70% of their 1-RM weight. To verify the consistency of deep squat movements performed under DLK and RDLK conditions, intra-rater reliability was analyzed using intra-class correlation . The biomechnical variables of the lumbar joint were calculated during DLK and RDLK deep squats. Paired sample t-tests (IBM SPSS 27.0, Armonk, New York, USA) were used for statistical verification. RESULTS During the deep squat movement performed in DLK and RDLK conditions, the peak angles of the ankle, knee, and hip joints, the minimum height of the pelvis, and the time and tempo showed statistically high reliability, confirming the accuracy of the movement. The peak flexion angle and moment, left flexion moment, left rotation moment, and compression force factors of the lumbar joint during deep squat were significantly lower in RDLK than in DLK. CONCLUSIONS Restricting lumbar dynamic kyphosis during deep squats is essential for decreasing the risk of lumbar joint injury.
PURPOSE This study aimed to analyze the differences in ground reaction forces (GRF) and pelvis and trunk kinematic patterns between groups based on ball speed during pitching. METHODS Twenty-nine males were recruited for this study. Participants were categorized based on ball speed into high (HG), medium (MG), and low (LG) ball speed groups. Statistical analysis was performed using one-dimensional statistical parametric mapping (SPM1D) one-way analysis of variance to compare GRF and pelvis and trunk kinematic patterns, followed by Bonferroni post-hoc tests. RESULTS Drive leg anterior and resultant GRF were greater in the HG than in the LG (p<0.001). The posterior GRF of the stride leg in the HG was greater than in the LG (p<0.008). Additionally, the vertical GRF of the stride leg was greater in the HG than in the LG (p<0.003), as was the resultant GRF of the stride leg (p<0.003). CONCLUSIONS The GRF of the drive and stride legs was significantly related to ball speed, indicating that a pitching strategy to maximize the GRF of the drive and stride legs is required.
PURPOSE This study sought to analyze the velocity and asymmetry between bilateral lower extremity mechanics according to the load during walking. METHODS A total of 14 adults with right leg dominance participated in this study (Male=7, Female=7). We respectively applied 30% of body weight load carriage on the subjects. Gait characteristics were analyzed with 3-dimensional cinematography and ground reaction force (GRF) system consisted of a center of gravity (COG) velocity, center of pressure (COP) area, leg stiffness, and GRF components. RESULTS Change in velocity of the maximum-minimum COG showed statistically significant in the main effect of load. The 1st anterior-posterior GRF (braking force) and vertical GRF were statistically significant in the main effects of load and bilateral lower limbs. The 2nd anterior-posterior GRF (propulsive force) was statistically significant in the main effect of load. COP area and leg stiffness exhibited statistically significant differences in the main effects of load and bilateral lower limbs. Interaction was observed in the vertical GRF, COP area. Furthermore , one-way variance analysis revealed load main effect had a greater influence on the increase in the magnitude of the vertical GRF and COP area than the asymmetry of bilateral lower limbs. CONCLUSIONS This study revealed the differences in asymmetry between the dominant and non-dominant lower limbs according to the load during walking. These findings may explain the differences shock attenuation and stress mechanisms between the bilateral lower limbs.
PURPOSE This study examined the effects of focus of attention on beginning golfers’ competitive anxiety and motor performance. METHODS Forty-eight college students with no prior golf putting experience were selected as participants and randomly assigned to internal-focus, external-focus, holistic-focus, and control groups (12 participants each). All subjects performed 5-m golf putting in acquisition, noncompetitive, and competitive situations. RESULTS In competitive situations, the internal-focus, holistic-focus, and control groups showed golf putting accuracy and consistency similar to those in noncompetitive situations, whereas the external-focus group’s golf putting accuracy and consistency were significantly lower in competitive situations than in noncompetitive situations. In addition, the holistic-focus group showed significantly higher golf putting accuracy than the control group in both competitive and noncompetitive situations. CONCLUSIONS Holistic-focus can be used effectively as a strategy for beginners to learn motor skills and reproduce learned motor skills when state anxiety increases. However, external attention focus cannot be considered a strategy to induce effective beginners’ exercise performance when competitive state anxiety increases.
PURPOSE This study sought to investigate the effects of passive warm-up on flexibility, exercise performance, and lactate oxidation rate in track and field athletes. METHODS A total of eight male athletes with more than three years of athlete experience were recruited as participants, and passive warm-up (PW) and active warm-up (AW) treatments were conducted in a single-group crossover study design. The participants performed thermal stimulation at 40°C for 20 minutes as a PW and performed a 60-70% HRmax cycle as an AW. Flexibility and exercise performance were measured after each treatment. Anaerobic power was measured using the Wingate test, and lactic acid concentration was measured. RESULTS Body temperature significantly increased in both PW and AW, and no significant difference was observed in exercise performance between treatments. Flexibility and lactic acid oxidation rate were significantly higher in PW than in AW. CONCLUSIONS In track and field sprinters, PW did not exhibit any significant difference in anaerobic power and exercise performance compared to AW even though no physical exercise was performed, and PW was effective in body temperature, lactic acid oxidation rate, and flexibility. PW suggests the possibility of replacing AW.
PURPOSE This study analyzed differences in ball speed and kinematic, kinetic characteristics according to stride length. METHODS Forty participants recruited for the study were divided into two groups based on stride length: an over stride group (overstride, OS) and an under stride group (understride, US). Independent sample t-tests were conducted to analyze differences in pelvis and trunk kinematics, ground reaction forces (GRF), and timing of pitch between groups. RESULTS Significant differences were found between groups in drive leg GRF impulse, pelvis, trunk closed angle and pelvic angular velocity (p<.05). Furthermore, the OS had statistically later pitching timings than the US at stride foot contact, maximal external rotation, and ball release phases (p<.05). CONCLUSIONS The maximized drive leg GRF impulse created a wider stride, significantly increasing the pelvis and trunk’s opening angles. Additionally, the OS displayed characteristics of later pitching timings compared to the US. However, since no significant differences in ball speed were observed between groups based on stride length, perhaps stride length does not contribute directly to ball speed. Future research should investigate optimal stride length tailored to individual flexibility and physical characteristics.
PURPOSE Recently, the need to improve service quality to provide an ideal viewing experience for sport OTT service users has increased. This study aimed to analyze user reviews of the SPOTV Now app, an OTT service specializing in sports in South Korea, to identify major perceptions of viewers and suggest measures for improvement. METHODS Review data (8,512) recorded on the SPOTV Now app were collected from November 21, 2017 to November 30, 2023. LDA-based topic modeling analysis was conducted along with a series of data preprocessing processes. Sentiment analysis was carried out through machine learning logistic regression analysis and odds ratio scores were calculated. RESULTS A total of five topics were derived, including ‘member management service', 'service stability', 'sport streaming service', 'sport video service', and 'subscription service'. Sentiment analysis indicated that 'exclusive', 'server', 'payment', 'log-in', 'authentication', 'pay', 'subscription', 'advertisement', 'play', and 'loading' were the top ten keywords. CONCLUSIONS Sport OTT operators should be more responsive to user requests and feedback, and video playback and server error problems should be improved for service stability. It is necessary to secure diversity as well as exclusivity of content, in addition to minimizing advertising or preparing various rate types, so that app users feel that they receive high value for their money.
PURPOSE This study seeks to contribute to the enhancement of the performance of domestic wheelchair racers by producing 3D-printed customized gloves and verifying their application effect. METHODS A total of three male wheelchair racers who belong to the T54 and have won gold medals in the National Para Games within the last three years were selected as subjects. Each subject performed three session s of muscle activity and maximum speed measurements before and after applying a 3D-printed glove during the stroke and recovery phases of wheelchair racing, focusing on the pectoralis major (PM), triceps brachii (TB), and erector spinae (ES) muscles. To standardize the muscle activity measurement data, the relative muscle activity level (%) for each section was calculated by maximum voluntary isometric contraction (MVIC) for each subject. All maximum speeds of each round of driving were calculated by the average record for comparative analysis. In addition, to verify the effectiveness of applying the 3D-printed glove, the Wilcoxon signed rank test, which is a non-parametric test method, was performed on all measured values using SPSS 24.0. RESULTS This study derived the following results. First, a statistically significant difference was observed in the muscle activity of each major muscle before and after using the 3D-printed glove. In common, an increase in muscle activity of the PM, TB, and ES was confirmed in the stroke section, and an increase in muscle activity of the TB was confirmed in the recovery section. Second, a statistically significant difference was documented in the maximum speed before and after using the 3D-printed glove. When using 3D-printed gloves, the maximum speed increased by 4.57, 3.63, and 1.06km/h for Payer A, and by 5.9, 6.04, and 7.86km/ h for Player B. In the case of Player C, the speed increased by 6.73, 2.27, and 0.83km/h, and all three players improved their maximum speed through the 3D-printed gloves. CONCLUSIONS Our study suggests that the application of 3D-printed customized gloves can have a positive impact on the performance of wheelchair racers. If the application of 3D-printed customized equipment is extended to athletes in a wider range of sports in the future, this could significantly contribute to the improvement of performance in domestic disability sport.
PURPOSE This study aimed to investigate the effects of accelerated rehabilitation exercise on physical fitness, lower extremity isometric strength, and blood variables in older adult women diagnosed with degenerative osteoarthritis. METHODS A total of 29 older adult women diagnosed with degenerative osteoarthritis residing in G city participated in the study, and 19 participants, excluding dropouts, took part in the experiment. They underwent exercise twice a week for 60 minutes per session over a period of 12 weeks. Pre- and post-experiment, the older adult fitness assessment (SFT), lower extremity isometric strength, and blood variables were measured. Data analysis was performed using SPSS 25.0, and paired sample t-tests were conducted to examine the effects before and after exercise. RESULTS The study results showed significant differences in body mass index (BMI) before and after exercise (p<0.05), and the older adult fitness assessment (SFT) showed significant differences in all items (p<0.01). Lower extremity isometric strength showed significant differences in absolute (Nm) and relative (%BW) values of 20° right flexion muscle (p<0.01). In terms of blood variables, significant differences were observed in creatine and ESR before and after exercise (p<0.01). CONCLUSIONS This study’s results suggest that regular physical activity and rehabilitation exercise programs can positively impact the muscular strength, cardiovascular endurance, exercise function, and blood composition of older adult women diagnosed with degenerative osteoarthritis. It is indicated that conducting future research, including periodic exercise programs, could be beneficial in promoting sustained exercise participation.
PURPOSE This study aimed to understand the changes in the exercise behavior of participants in the exercise-psychological counseling program. METHODS This study sampled adult female participants of C diet camp in Seoul, who were in stages 2~3 of the “Stages of Change Model.” A total of 60 participants were randomly assigned to the counseling group (n=30) and control group (n=30). During the 12 weeks of study, all subjects participated in the diet camp program C. The counseling group participated in the exercise psychological counseling program once a week, while the control group participated in recreational activities instead. Exercise adherence, outcome-expectancy, and satisfaction were measured once every four weeks. Latent growth models were used to analyze the measured data. RESULTS Exercise adherence, outcome-expectancy, and satisfaction in the counseling group exerted a statistically significant positive effect. A statistically significant positive effect on the change of exercise adherence variable was observed in the control group, but the trend was only 1/4 of that of the counseling group. In the control group, exercise outcome-expectancy and exercise satisfaction did not have a statistically significant outcome. CONCLUSIONS The exercise counseling program is an essential intervention strategy that enhances participants’ exercise adherence, outcome-expectancy, and satisfaction. Therefore, a positive change in exercise behaviors occurs.
