The human foot is only part that directly contact between the body and the external environment, and is ideally positioned to provide sensory information to the Central Nervous System (CNS) during static and dynamic tasks. Through cutaneous mechanoreceptors located in the dermis, the foot is able to recognize touch pressure and vibration stimuli, which provide important feedback information used for the fine coordination of movements. The purpose of this study is to quantitatively examine the effect of changing the foot cutaneous sensory by temperature stimulus on maximal performance and muscle activation using wavelet technique. Sixteen healthy subjects volunteered to participate in this study (Male: Age 21.4±2.4years; Height 174.7±5.3츠; Weight 70.6±5.2kg; Female: Age 20.5±0.6years; Height 163.2±3.1cm; Weight 55.6±4.8kg). Sensory pressure thresholds were determined for the plantar surface of the foot using monofilament. Kinematic, kinetic and EMG data which relative to maximal performance were collected while squat jumping in each temperature condition(cool 12-15℃ normal 28-30℃ hot 45-48℃). Maximal jump height was significant higher in normal condition. Vertical GRF in normal condition showed higher peak value the other conditions. And then EMG signal were significant different between temperature conditions during maximal performance. By changed sensory feedback on temperature, one can alter maximal performance and muscle activation pattern. Cutaneous feedback is important in performance and neuromuscular control, and temperature changes significantly influence on lower extremity during maximal squat jump performance of healthy subjects.
The purpose of this study was to examine the effect of dietary creatine and leucine supplementation on protein synthesis and functional properties of skeletal muscle during 8 weeks of resistance exercise. Thirty two male Sprague-Dawley rat(5 weeks old) were randomly divided into four groups(8 rats per group): sedentary control group(CON), execise group(E), exercise with creatine supplementation group(EC), exercise with creatine, leucine supplementation group(ECL). Exercise groups were trained to climb a ladder with a weight secured to their tails(3day/week). The supplementation was administrated daily through oral gavage. Creatine supplementation was given at 250㎎/㎏/day. Creatine+leucine supplementation was given at 250+250㎎/㎏/day. All exercise groups presented significantly lower epididymal fat mass than CON(p<.05). E presented significantly higher plantaris mass than CON(p<.05). All exercise groups significantly presented higher FHL mass than CON(p<.05) and E presented higher FHL mass than EC, ECL(p<.05). EC, ECL presented significantly lower expression of Akt/PKB protein than CON, E(p<.05). There was no difference in the expression of mTOR protein. The results suggest that the creatine and leucine supplementation does not promote any additional hypertrophic effect on resistance trained skeletal muscle. But, creatine and leucine supplementation might have a potential benefit on skeletal muscle hypertrophy through the activation of protein synthesis.
PURPOSE This study examined levels of safety knowledge and practice among recreational sports participants, focusing particularly on impacts of gender, age, injury experience, and exercise-level profile. In sports environments, understanding these factors is essential for developing targeted strategies to promote safe behaviors. METHODS Survey data from 7725 participants engaged in regular recreational sports activities were analyzed. Latent Profile Analysis was employed to categorize participants based on their injury experience and exercise levels, resulting in two profiles: Group 1 (moderate or severe injury experience with intermediate exercise levels) and Group 2 (mild injury experience with beginner exercise levels). Three-way ANOVA was then used to evaluate relationships between these profiles and safety knowledge and practice levels. RESULTS Results revealed significant differences across sex, age, and profile groups. Compared with women, men demonstrated higher levels of safety knowledge and practice, which were likely influenced by greater exposure to high-intensity sports and risk-taking tendencies. Adolescents exhibited the highest levels of safety knowledge and practice linked to structured safety education, but these levels declined in early adulthood and then increased again in middle age due to growing health awareness and preventive motivations. Furthermore, participants in Group 1 consistently showed higher levels of safety knowledge and practice than those in Group 2, highlighting injury experience’s role in shaping safety behaviors. CONCLUSIONS These findings underscore the importance of developing gender-specific safety education programs, age-appropriate interventions, and training initiatives tailored to beginning participants. Future research should evaluate these strategies’ long-term impact on safety practices and injury prevention in diverse sports settings.
Purpose The purpose of this study was to investigate the effect of vibration therapy on the functional, imaging, and mechanical properties in elbow flexor after a single bout eccentric exercise. Methods Twenty-three untrained adults male participated in this study [CON(control)= 11, VT(vibration)= 12]. Volunteers performed 5-set of 6 maximal (90˚/s) eccentric contractions of the non-dominant elbow flexor on a isokinetic dynamometer. Vibration was applied using a side alternating vibratory platform (12 Hz frequency, 4 mm amplitude) with 3-set of 60 sec during 3-day after eccentric exercise. Results The VT group showed a reduction in exercised-induced muscle damage(EIMD) symptoms in the form of attenuating muscle swelling and echo intensity (P<.05) compared with the CON, mechanical properties were improvement (P<.05) compared with the CON. However, muscle soreness, range of motion and maximal voluntary isometric contraction were not significant (P<.05). Conclusion As currently practiced, vibration therapy after eccentric exercise may reduce EIMD by improving quality of the muscle, suggesting that this therapy is an effective strategy for EIMD.
Purpose The study examined the effects of a 12-week high intensity circuit training (HICT) on abdominal fat, physical fitness, blood lipids, and insulin resistance in middle-aged obese women. Methods Thirty obese women, aged 32-48 yrs, were recruited and randomly assigned to either HICT group (TR; n = 15) or control group (CON; n = 15). Subjects in the TR group participated in HICT of which resistance exercise and aerobic exercise were performed with a duration of 40 min/session and 3 sessions/wk for 12 weeks, whereas subjects in the CON group were asked to maintain their normal life patterns. Dependent variables included abdominal fat area, body composition, physical fitness, blood lipids profiles, and insulin resistance index. Analysis of variance with repeated measures with Bonferroni corrections was used to compare the outcomes between two groups. Results Main findings of the present study were as follows: 1) compared to the CON group, the TR group had significant reductions in overall (i.e., body mass index and percent body fat) and abdominal obesity (i.e., waist circumference, total abdominal fat area, visceral fat area, subcutaneous fat area, and visceral fat area-subcutaneous fat area ratio), 2) compared to the CON group, the TR group had significant improvements in health-related physical fitness (i.e., muscular strength, muscular endurance, muscle power, flexibility, balance, and cardiorespiratory endurance), and 3) compared to the CON group, the TR group had significant improvements in fasting lipids, glucose, insulin, and insulin resistance. Conclusions The current findings of the study suggested that HICT would be an effective exercise intervention to improve metabolic complications associated with obesity and poor physical fitness in obese middle-aged women.
Purpose The purpose of this study was to determine the effectiveness of six-weeks intermittent hypoxic training at 3,000 m hypobaric hypoxic condition on aerobic and anaerobic exercise capacity in competitive swimmers. Methods South Korean swimmers (n=20) were randomly assigned into training at sea-level (n=10, intermittent normoxic training group; INT) and training at 526 torr corresponding to 3,000 m hypobaric hypoxic condition (n=10, intermittent hypoxic training group; IHT). The participants completed an aerobic continuous treadmill training (30 min) within 80%HRmax and anaerobic interval bicycle training (10 times; 2 min of exercise and 1 min of rest) for 30min within 90%HRmax in each environment. We compared their aerobic and anaerobic exercise capacity before and after six-weeks of training. Exercise frequency was 1 hour, 3 days per a week, and during 6 week. Results In aerobic exercise capacity, PWC at 75%HRmax, estimated VO2 max, and exercise time were increased by training in only the IHT group. Estimated VO2 at 75%HRmax was increased by training in both groups, but presented a larger increase tendency in the IHT group compared with the INT group. In anaerobic exercise capacity, peak anaerobic power and fatigue index were increased by training in only the IHT group. Blood lactate level after wingate test were decreased by training in both groups, but the IHT group have a lower blood lactate level in after training compared with the INT group. Conclusion In our study, we did not measure to various dependent variables for support to enhancement of aerobic and anaerobic exercise performance. However, these results showed that the IHT method may be effective in improvement of exercise performance in competitive swimmers who participates in a variety of events from short to long distance.
PURPOSE This study analyzed the relationship among coaching behaviors, motivational climate, sports competence, effort, and failure tolerance as perceived by high school athletes. Additionally, it examined whether motivational climate, competence, and effort mediate the relationship between coaching behaviors and failure tolerance. METHODS Using questionnaires measuring autonomy-supportive coaching behavior, controlling coaching behavior, motivational climate, sports competence, effort, and failure tolerance, 365 high school athletes were surveyed. Using SPSS 28.0 and Amos 28.0 software, descriptive statistics and structural equation modeling were conducted along with the following types of analyses: reliability, correlation, confirmatory factor, convergent validity, and discriminant. Additionally, the bootstrap method was used to verify serial multiple mediating effects. RESULTS Autonomy-supportive behavior had a significant positive effect 1) on motivational climate, sports competence, and effort and 2) on failure tolerance. 3) Controlling coaching behavior had a significant negative effect on motivational climate and sports competence. 4) Motivational climate and 5) sports competence both had a significant positive effect on effort. 6) Effort had a significant positive effect on failure tolerance. Last, in the relationship between autonomy-supportive behavior and failure tolerance, motivational climate, sports competence, and effort showed partial mediating effects. CONCLUSIONS This study confirms the importance of coaches’ autonomy-supportive behavior in determining failure tolerance among adolescent athletes. Based on this information, counseling (educational) programs aimed at enhancing performance can be developed and provided in sports settings, thus fostering success among athletes.
PURPOSE This study investigated the effects of 12 weeks of clubbell and stepbox training on physical fitness, badminton skills, and fatigue in male badminton, grade A (top grade) club members aged 20–30s, with over 5 years’ experience. METHODS Participants in a training group (TR: n=15) engaged in 12 weeks of clubbell and stepbox circuit training involving maximum 8–12 reps of clubbell exercises and stepbox exercises at over 77% of HRmax for 50–55 min/sessions three times a week. Participants in a control group (CON: n=15) maintained their normal lifestyle pattern during the same intervention period. Dependent variables were measured and compared using repeated measures two-way ANOVA. RESULTS The main results were as follows: 1) The groups showed no significant differences in body composition. 2) Regarding physical fitness, VO2max, relative peak power, relative average power, grip strength, push ups, repeated jump squats, SSPT (seated single-arm shot-put test), 10 m sprint, and hexagon agility increased significantly in the TR, while push ups decreased significantly in the CON. 3) As for badminton skills, forehand clear accuracy, badminton agility, badminton endurance, and smash speed increased significantly in the TR. Forehand clear accuracy decreased significantly in the CON, but badminton agility and smash speed increased significantly. 4) The groups showed no significant differences in fatigue. CONCLUSIONS In male badminton club members aged 20–30s, 12 weeks of clubbell and stepbox circuit training effectively improved physical fitness and badminton skills. However, lack of any improvement in body composition and fatigue warranted further research in these areas.
PURPOSE This study aimed to investigate the effects of regular moderate- and vigorous-intensity aerobic exercise on body composition, resting metabolic rate, and blood lipid profile in normal-weight obese women. METHODS The participants in the study were normal-weight obese women in their 20’s, divided into moderate- and vigorous-intensity aerobic exercise (VIAE) groups. Aerobic exercise was performed three times a week for 8 weeks. To verify the exercise effect, pre- and post- body composition, resting metabolic rate, and blood lipid profile were analyzed. RESULTS Weight and body fat decreased in both groups, and lean body mass and resting metabolic rate increased in the VIAE group. Blood TC, TG, and LDL-C decreased in both groups and HDL-C increased in the VIAE group. CONCLUSIONS In normal-weight obese women, vigorous-intensity aerobic exercise is more effective than moderate intensity aerobic exercise for improving body composition, resting metabolic rate and blood lipid profile.
PURPOSE The purpose of this study was to identify a sport-specific assessment for elite race walking athletes by comparing physiological responses to different types of walking graded exercise test (GTX) protocols. METHODS Six elite race walking athletes completed two types of walking protocols in a randomized crossover design with 1 week of interval between trials. Exercise time, oxygen uptake (VO2), ventilation (VE), and heart rate (HR) were measured in each trial; the lactate level was measured during the recovery period. RESULTS VO2, VE, and HR differed significantly between the trials (p<.01~.05). Exercise time (p<.01) and VO2 (p<.05) differed significantly between the walking protocols; however, VE and HR did not differ significantly. During the recovery period, lactate levels differed significantly between the trials (p<.01), but not the walking protocol. CONCLUSIONS These results suggest that modified walking GXT protocols were appropriate to assess elite race walking athletes.
