PURPOSE The purpose of this study was to compare the dynamic postural control of youth athletes with and without a history of lateral ankle sprains. METHODS Twenty-eight youth athletes (14 lateral ankle sprain, 14 healthy control) participated in this study. All participants answered the Foot and Ankle Ability Measure questionnaire and were subject to the Star Excursion Balance Test (SEBT) for dynamic postural control evaluation to collect the joint angles of the lower extremity, a center of pressure (COP) path, and COP velocity. Independent sample t-test or Mann-Whitney U-test were performed to analyze the difference between the groups. RESULTS The lateral ankle sprain group (LAS) was found to have a long experience in participating in sports, and low Foot and Ankle Ability Measure scores were identified when compared to the healthy control (CON; p<0.05). LAS was observed with a short reach distance, less hip flexion, and dorsiflexion angles during the anterior direction of SEBT when compared to CON (p<0.05). Furthermore, LAS showed a slower anteroposterior and mediolateral center of pressure velocities in the posteromedial aspect of SEBT and a slower anteroposterior COP velocity in the posterolateral aspect of SEBT when compared to that of CON (p<0.05). There were no differences between the groups with respect to the other variables (p>0.05). CONCLUSIONS Based on these results, decreased anterior reach distance of SEBT may be affected by changing the dynamic posture control strategy of the lower extremity joint on the sagittal plane in LAS.
Purpose The present study explored biological autonomy and control of function in circumstances that assessed a presumed relationship to an environmental cycle. An understanding of this behavior appeals to the organism-environment system rather than simply the organism—we seek to expose the laws that underlie end-directed capabilities by measuring biological characteristics (motor synchrony) in an environmental cycle (circadian temperature). Methods Participants (n = 24) at the University of Connecticut (Storrs, USA) and the Seoul National University (Seoul, Korea) served in the study. The production of in-phase bi-manual coordination was examined at different circadian points (allowing comparison of day-night temperature effects) in two experimental designs; (1) normal temperature embedded in a 24 hour cycle (5:00, 12:00, 17:00, and 24:00), and (2) normal versus abnormal temperature [artificially decreasing or increasing] while embedded at two points (5:00 am, 5:00 pm) during the circadian process. A typical bi-manual stability measure varied significantly as a function of the day-night temperature cycle. Results While (i) circadian effects under the artificially perturbed temperature manipulation were not straightforward along the day-night temperature cycle, (ii) the circadian effect divided by the ordinary circadian seems to be constant along the day-night temperature cycle. Conclusions The discovery of direct and robust relation between biological aspects (body temperature and motor synchrony) an environmental process (circadian temperature cycle) may echo adaptation of our biological system to the environment. This relation supports the claim that the organism and the environment should be considered as integrated system in which biological (or physical) dynamics takes place as a mutual factor.
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.
Purpose The purpose of this study was to investigate the effects of a functional fatigue protocol on lower extremity dynamic and static postural control. Methods A total of 20 physically active collegiate students participated in this study (ten males, ten females; age 22.5±2.7 years; mass 67.0±13.0 kg; height 168.0±8.9 cm). A unilateral stance with eyes closed for 10 seconds was performed to test static postural control using a balance force plate and single-leg drop landing on 30cm box was performed as a dynamic postural control test and captured using VICON motion analysis system. Results The results of this study showed an average heart rate of 176.3 beats/minute, an 18 rating on the perceived exertion scale, significant differences in blood lactate, and a static postural control deficit after fatigue as compared with before fatigue(p<.05). Dynamic postural control after fatigue changed landing strategy in the form of stiff landing. Knee flexion was decreased at initial contact and at peak vertical ground reaction force, also, both decreased valgus and internal rotation of knee joint. Conclusions This protocol may use for enhancing fatigue-endurance training as well as for inducing fatigue. Further, to ascertain a landing strategy, it is recommended to increase landing height to clearly observe changes in landing strategy.
Purpose The purpose of the study was to investigate the effect of vibratory stimulus on the static postural control of 8 healty senior adults. Methods To achieve this goal, all subjects participated in two different kinds of static postural control tasks. Task 1 was a static postural control task, where both-legs stand on the ground. Second task was an unstable static postural control task using only single leg stance. As they maintain their balance, 6 different vibratory stimulus were provided on the sole of their feet(personal threshold 0%, 80%, 90%, 100%, 110%, 120%). Results The results of the study were as follows: First, there was no significant differences in postural control ability according to different types of vibrator intensity. Second, there was a significant difference in single-leg postural control ability according to vibrator intensity. Third, there was a significant difference in anterio-posterior stability according to the different types of vibrator intensity. Conclusion Stochastic resonance using vibratory stimulus was more effective in the single leg stance task, rather than the double leg stance task. Moreover, sub-threshold vibratory stimulus(80%, 90%) intensity were more effective than higher vibratory stimulus(100%, 110%, 120%).
Purpose: The purpose of the present study was to identify the difference of overall putting accuracy and/or distance control among three visual conditions; executing putt focusing vision on the near target(ball), focusing on the far target(hole), and with no vision. In order to satisfy ecological validity, the test was held not on the synthetic putting green in a laboratory, but on the outdoor real putting green. Methods: A putting green with slight slope and minimal break was selected as the test site. The test was held at 8.5m uphill, 13m uphill, 8.5m downhill, and 13m downhill. Twenty participants were asked to putt the ball as close to the target as possible. They were also asked to adhere to their own pre-putt routine having enough time of visual fixation toward the hole to get distance and direction cues. Each Participant putted a total of 12 balls putting 3 balls on each distance-slope experimental condition. Overall putting accuracy score represented actual distance (in meter) from the far target(hole) to the ball rest. Distance control score represented it from the near target(original ball position) to the ball rest. Repeated measure ANOVA was used to verify the raw data. Results: Putt from 8.5m uphill and putt from 13m downhill were revealed to have statistically significant difference only in distance control by visual focus conditions. Putt focusing vision on the ball was the best at 8.5m uphill. Putt focusing vision on the hole was the best at 13m downhill. However, there was no significant difference in overall putting accuracy by visual conditions. Discussion & Conclusion: The results of our study are interesting and valuable from two aspects. First, the presumption is that overall putting accuracy on the real putting green has no significant difference by visual conditions because it is affected by various factors, i.e. memory of distance, slope, break, turf condition, impact quality, body alignment, etc. Second, no consistent evidence was detected that specific visual condition, especially executing putt focusing vision on the hole, was the best for distance control.
Purpose The purpose of this study was to compare the differences between the three simple control models of Hayes (2012) and to determine whether there were Moderating Effects depending on the level of self-esteem, willpower and belief that are psychological factors in the relationship between athlete's retirement and Athlete's period. Methods To achieve this objective, a total of 259 retirees were collected from data on retirement and psychological factors. The data processing method presented the reliability and feasibility of the measuring instrument through technical statistics, frequency analysis, confirmation factor analysis, and reliability analysis. In addition, we conducted a hierarchical regression analysis using the PROCESS command statement in IBM 20 to examine the regulatory effects. Results The results of the study are as follows: The first was the significant model of Hayes (2012)'s three simple control models. It is up to the researcher to choose which model to choose, but when selecting the model, the justification of the variables must be established on the basis of theoretical basis, and the reliability of the variables must be put in to produce reliable and reasonable results. The second was to verify that the relationship between the retirement factor(10) and the Athlete's period has an adjustment effect based on self-esteem, willpower and belief. Among the psychological factors, the Moderating Effects was greatest in the influence of belief on the Athletes' period, and the more reasons for retirement, the longer the Athletes' period than the weaker. The combined mental strength of all three psychological factors combined shows that the combined effect of control also significantly increases the player's ability to survive by combining with the retirement factor. In particular, sportsmanship has resulted in a better mix of retirement factors than the sense of Self-esteem and will, resulting in a longer increase in the capacity. Conclusions Therefore, players who long for a player always keep their dreams of becoming a big star in mind, and ask me to always keep the belief in hope that I will enjoy my career for a long time.
The purpose of this study was to examine the influence 12 weeks of Hatha yoga exercise has upon changes in postural control ability of high school girls. The research subjects were 27 high school girls (yoga group: 15, control group: 12). Changes that took place after yoga exercise were comparatively analyzed after having them train Hatha yoga for 12 weeks. The research variables that were measured were the moving range of COP in static postural balance, Rambling & Trembling in the moving range of COP, and postural change in the sagittal plane. The mean and the standard deviation(SD) were calculated on each measurement item by using the SPSS Ver 21.0 statistical program. To verify difference in pre-value between groups, an independent t-test was carried out. The verification of change according to time within the group after 12 weeks of yoga exercise was conducted in a paired t-test. To inspect interaction by time and group before and after yoga exercise, two-way repeated measures ANOVA was implemented. As a result, the moving distance of the pre and post direction in the moving range of COP was reduced. Rambling and Trembling in the pre-and-post direction significantly decreased. And in postural change of the sagittal plane, there was significant interaction between two groups in the neck and thigh parts. It was thought that the 12 weeks hatha yoga exercise has positive influence upon improving the postural control mechanism in female high school students and has an effect even on change in the postural control ability of an individual.
PURPOSE This study aimed to investigate the current status of KADA’s chaperone management in order to suggest policy proposals for the establishment of a stable and sustainable chaperone pool. METHODS We conducted a literature review and document analysis, along with formal and informal dialogues with experts to supplement the data that could not be obtained through these methods. RESULTS This study suggested practical ways for KADA to establish a chaperone pool by leveraging the government’s volunteer platform and collaborating with universities that have sports-related departments across Korea. In addition, it proposed specific approaches to promote and encourage university students to engage with chaperoning. CONCLUSIONS It is anticipated that this study will facilitate the implementation of the proposed policies in the field of sports and position KADA as a model for other NADOs in terms of chaperone pool composition.
PURPOSE This study aimed to identify the lower limb muscle activity based on direction prediction presence or absence and gender during side cutting in healthy college students. METHODS The study participants included 14 healthy males and females (8 males; 6 females). All participants ran at full speed for a distance of 12m, and side-cutting was carried out at 45 degrees in a randomly indicated direction and in a fixed direction. Simultaneously, data regarding vastus medialis, vastus lateralis, semitendinosus, and biceps femoris muscle activity of the dominant leg were collected using an electromyography sensor, and data regarding vertical acceleration were collected using an inertial sensor attached to the pelvis. A sync webcam was used for obtaining the initial contact of side cutting and the stance period time. During the 10 milliseconds (pre-activation) prior to the initial contact and 50% of the stance phase (loading phase), vastus medialis, vastus lateralis, semitendinosus, and biceps femoris average muscle activity and hamstring to quadriceps ratio included as variables. RESULTS During the pre-activation and loading phase, the vastus medialis muscle activity of the male group was higher in the unexpected condition than in the expected condition. Furthermore, hamstring to quadriceps ratio was confirmed to be lower under unexpected condition compared to under expected condition during on loading phase. CONCLUSIONS The study results suggest that the risk of anterior cruciate ligament injury may increase with side cutting under unpredictable conditions. It is expected to provide useful information for identifying factors related to knee injury in the general population.
