Purpose The purpose of this study was to evaluate the effect of detachable forefoot outsole on muscle activity of the lower extremity during downhill walking. Methods Thirteen male university students (age: 23.5±2.1 yrs, height: 175.7±4.6 cm, weight: 651.9±55.5 N) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked down 20° ramp with forefoot’s design for the detachable outsole’s angle(5°, 10° and 20°) and type(A and B). To assess the myoelectric activities of selected muscles, six of surface EMG(QEMG8, Laxtha Inc. korea, sampling frequency = 1,024 Hz, gain = 1,000, input impedance > 1012 Ω, CMRR > 100 dB) electrodes with on-site pre-amplification circuitry were attached to ES, RF, BF, TA, LG, and MG. For each dependent variable, two-way ANOVA with repeated measures was used to determine whether there were significant differences among forefoot’s design for the detachable outsole’s angle and type (p<.05). When correlation effect was not statistically significant, post hoc analyses were performed using the multiple comparison through bonferroni, and if correlation effect was statistically significant, one-way ANOVA was performed as for the form of outsole which is an inter-group variable in order to find out simple main effect, and the paired t-test was performed to find out the angle of outsole, which is an intra-group variable. Results In IDLS phase, In terms of Rectus Femoris, 10°-B outsole showed statistically higher muscle movement than 5°-B, 5°-A outsole showed statistically higher muscle movement than 5°-B, 20°-A outsole showed statistically higher muscle movement than 20°-B. Among these outsoles, Conclusion 5°-B outsole was found to the most useful outsole for improving stability and controlling the bodily movement due to the body weight load when walking down the ramp.
Purpose This study was designed to examine the effects of 8 weeks of circuit exercise training on blood lipids, insulin resistance, cardiovascular function, and metabolic syndrome risk factors in 40~50s male bus drivers. Methods Twenty-nine bus drivers were randomly assigned to one of two groups, i.e., circuit exercise training group (TR: n=14) and control group (CON: n=15). Subjects in TR participated in circuit exercise training 30-40 min per session, three sessions per week for 8 weeks, whereas subjects in CON were asked to maintain their normal life pattern for same intervention period. The variables regarding body composition, blood lipids, insulin resistance, cardiovascular function, and number of metabolic syndrome risk factors were measured and compared between two groups as well as between pre- and post-test. Data were analyzed using repeated two-way ANOVA with post hoc test. Results Main results of the present study were as follows: 1) Waist circumference, waist-hip ratio, body mass index, and percent body fat decreased significantly in TR. 2) LDL-C decreased and HDL-C increased significantly in TR. 3) Fasting plasma insulin and HOMA-IR decreased significantly in TR. 4) Regarding cardiovascular function, diastolic blood pressure and mean arterial pressure decreased significantly in both TR and CON. hs-CRP were not changed significantly; however, it tended to be decreased TR. 5) Number of metabolic syndrome risk factors decreased significantly in TR(2.86±0.86 to 1.50±0.76). Conclusions It was concluded that 8 weeks of circuit exercise training would be beneficial for improvement of blood lipid profiles and insulin resistance, resulting in preventing metabolic syndrome. In particular, it would be very clinically meaningful that number of metabolic syndrome risk factors decreased from 2.86±0.86 to 1.50±0.76 by the circuit exercise training.
The purpose of this study was to investigate the effects of 8 weeks of aerobic training and resveratrol supplementation on a body composition, physical fitness, insulin resistance, liver function, blood pressure, and heart rate. Fifty-one elderly women were randomly assigned to aerobic training group (EX: n=12), resveratrol supplementation group (R: n=13), combined aerobic training and resveratrol supplementation group (EX+R: n=12), and control group (CON: n=14). The subjects in EX group exercised three sessions per week, 40 minutes per session for 8 weeks, the subjects in R group took 500 mg of resveratrol per day for 8 weeks, and the subjects in EX+R group received both treatments. The subjects in CON group were asked to maintain normal daily life pattern without any treatment for the same period of intervention. Body composition, physical fitness, insulin resistance, liver function, blood pressure, and heart rate were measured at pre- and post-test and the data were compared among groups and between tests by utilizing two-way ANOVA with repeated measures. Main results of the present study were as follows: 1) Physique and body composition did not change significantly in all groups. 2) Muscular endurance increased significantly in EX+R group, whereas the other physical fitness-related variables showed no significant changes in all groups. 3) Fasting glucose, fasting insulin, HOMA-IR, and HbA1c tended to be improved in EX+R group. 4) AST, ALT, and γ·GT showed no significant changes in all groups. 5) Systolic blood pressure and diastolic blood pressure increased significantly in CON group. Heart rate tended to be decreased in EX+R group and EX group. It was concluded that the 8 weeks of aerobic training and resveratrol supplementation had positive effects on muscular endurance, insulin resistance, and blood pressure in T2DM elderly women. Research investigating the effects of a longer period of aerobic training and resveratrol supplementation on the same variables would be warranted in the future.
Purpose : The purpose of this study was to investigate coaching information with which coaches provided players during badminton competition. Methods : To this end, we generated an open-ended questions and presented it to 88 high school athletes registered in the Badminton Korea Association. The survey was conducted during a tournament and immediately after the tournament to collect the data. The collected data were categorized through inductive content analysis. Results : As a result of this study, a total of 480 raw data points collected through the open-ended survey were categorized into four general areas: psychological information, technical information, tactical information, and game operation information. Specifically, psychological information was divided into six subdivisions: concentration, confidence, relaxation/stabilization, mental toughness, play thought, and passion; technical information was broken into four subdivisions: strokes, footwork, swing and posture, and position preparation; tactical information had four subdivisions: coping to opponents, play changes, rotation, and manipulation of opponents; and, game operation information was divided into two subdivisions: taking the lead in a game and changing atmosphere. Conclusions : In other words, in badminton competition, the coaches strengthened psychological skills that promote psychological stability to attain the athletes’ peak performance and modified the athletes’ motion into the action necessary for achieving accurate techniques. Furthermore, they provided a variety of coaching information so that the athletes will respond appropriately to their opponents’ play, take the lead in games and induce a positive mood. The psychological, technical, tactical and game operation information offered by badminton coaches are the main factors influencing the performance of badminton players and suggest a need for the proper management and control of the coaches as well as athletes for the peak performance.
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.
PURPOSE This study aimed to investigate how a 10-week online live Pilates training held during the COVID-19 pandemic affected body composition, cardiovascular function, and physical fitness in sedentary middle-aged obese women. METHODS Thirty obese women, aged 30 to 49 years (BMI : 25kg/m2 or more; waist circumference: 85cm or more) who were leading a sedentary lifestyle for more than 8 hours a day were assigned to one of two groups—that is, the Pilates training group (TR) and the control group (CON). Four participants were dropped from the study during the intervention period. Participants in the TR group (n=13) performed online live mat Pilates exercises (3 sessions per week; 60 minutes per session for 10 weeks, whereas participants in the CON group (n=13) were asked to maintain their normal lifestyles during the same intervention period. Independent variables related to body composition, cardiovascular function, venous function in the lower body, physical fitness, and 1-RM (repetition maximum) were measured at pre-test and post-test, and data were compared between the two groups and between the two tests. RESULTS 1) Regarding body composition, body weight, body mass index, fat mass, and waist circumference decreased significantly in the TR group. 2) Regarding cardiovascular function, stroke volume and cardiac output increased significantly in the TR group, and total peripheral resistance decreased significantly in the TR group. 3) Regarding venous function in the lower body, blood flow velocity and blood flow volume of the parenchyma area increased significantly in the TR group. 4) Regarding physical fitness, cardiorespiratory endurance, muscular endurance, flexibility, and balance improved significantly in the TR group. 5) 1RM of biceps curl, lat pull-down, leg curl, and leg extension increased significantly in the TR group. CONCLUSIONS It was concluded that the 10-week online live Pilates training had positive effects on the body composition, cardiovascular function, venous function in the lower body, and physical fitness of middle-aged obese women leading sedentary lifestyles.
PURPOSE This study aimed to analyze the dynamic posture stabilization and kinematic variables between visual feedback and Y-balance training groups during jump-landing. METHODS Thirty-eight male players (age: 22.6 ± 1.12 years, height: 175 ± 3.54 cm, weight: 65.5 ± 5.11 kg) were included in this study, and chronic ankle instability was checked using Cumberland Ankle Instability Tool (CAIT) and Balance Error Scoring System (BESS). They were randomly assigned to the Visual biofeedback (Training group: TG, n = 19) and Y-balance groups (Control group: CG, n = 19) for four weeks. TG performed balance training using the Biodex balance system (BBS) and CG performed training using the Y-balance system. During jump landing, time to stabilization (TTS), force plate (COP, GRF); joint angle and moment were collected and analyzed. All analyses were performed with SPSS 21.0, and Bonferroni was used for repeated measured ANOVA and post-hoc. RESULTS The results indicated that there was an interaction between TG and CG in terms of AP and ML directions of TTS (p < 0.05). AP/ML TTS of the TG for the post-test was smaller than that for CG (AP: p = 0.000; ML: p = 0.046). ML TTS of the TG for post-test was smaller than at pre-test (p = 0.041), and AP TTS of the CG for ankle joint moment (p < 0.05). There was an interaction between TG and CG in terms of dorsiflexion (DF) and plantarflexion (PF) of joint moment (p < 0.05). Ankle moment of the CG for post-test decreased than at pre-test (DF: p = 0.040, PF: p = 0.032), and ankle dorsiflexion moment of the CG for post-test was decreased than at pre-test (p = 0.046). CONCLUSIONS Balance ability was achieved more effectively through visual biofeedback training than Y-balance training. Therefore, we recommend balanced training with visual feedback on chronic ankle instability.
PURPOSE Blood pressure (BP) in hypertensive individuals is reduced by the accumulation of post-exercise hypotension (PEH) induced by a long period of training. This study aimed to investigate the effects of intensity of two different aerobic exercises with identical energy expenditure on post-exercise blood pressure and cardiovascular function in prehypertensive men. METHODS Eleven prehypertensive men in their 30s participated in two trials repeatedly. In the first trial, the exercise was moderate in intensity and continuous (MICE) with 70% of VO2max, and the exercise in the second trial was high-intensity interval exercise (HIIE) with 50% and 90% of VO2max. Each exercise was performed for 30 min, and the variables related to BP and cardiovascular function were measured at certain times for 1 hr during the recovery phase. RESULTS Our main findings are as follows: (1) Systolic blood pressure was significantly lower at 30 and 45 min of recovery time than the baseline in the HIIE trial, and systolic blood pressure was significantly lower in the HIIE trial than the MICE trial at 10, 15, and 30 min of recovery time. (2) The rate pressure product was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (3) The heart rate was significantly higher in the HIIE trial than the MICE trial at 15, 30, 45, and 60 min of recovery time. (4) Stroke volume was significantly lower in the HIIE trial than the MICE trial at 30 min of recovery time. (5) Cardiac output was significantly higher in the HIIE trial than the MICE trial at 15 min of recovery phase. (6) Total vascular conductance was significantly higher in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. (7) Total peripheral resistance was significantly lower in the HIIE trial than the MICE trial at 15 and 30 min of recovery phase. CONCLUSIONS The HIIE shows a higher cardiovascular stress than MICE; however, HIIE contributes to the augmentation of PEH and improvement of cardiovascular function. Therefore, HIIE rather than MICE should be suggested in BP control and enhancement of cardiovascular function in prehypertensive males.
Purpose The purpose of this study is to emphasize the need for the establish and the use of altitude training center via examining exercise training method in natural or artificial altitude environment that is applied to various elite athletes in various advanced countries to maximize exercise performance and its effectiveness. Results Altitude training in natural or artificial altitude environment enhances aerobic and anaerobic exercise performance baesd on the hematological and nonhematological adaptations to hypoxic conditions. These altitude training methods can be classified into living high training high (LHTH), living high training low (LHTL), and living low training high (LLTH). LHTH (i.e., developed since the 1968 Mexico Olympics) and LHTL (i.e., developed in the 1990s by Levine and Stray-Gundersen) improve exercise performance via hematologic changes through erythropoiesis such as increased hemoglobin mass and erythrocyte volume. On the other hand, LLTH (i.e., has been developed variously since the 2000s) is composed continuous hypoxic training (CHT), intermittent hypoxic training (IHT) and repeated sprint training in hypoxia (RSH), and the altitude environment is constructed using a vacuum pump and a nitrogen generator. In general, LLTH method dose not induce hematological change in a short time within 3 hours. However, CHT and IHT enhance aerobic exercise capacity by improved exercise economy, supply and utilization of blood to tissues, capillary and mitochondrial densities, and oxidative enzyme activity through various biochemical and structural changes in skeletal muscle and cardiac muscle. RSH enhances anaerobic power and repetitive sprint performance by improving glycolytic enzyme, glucose transport, and pH control. In Korea, however, there are almost no facilities for altitude training that is applied to enhance athletic performance in advanced sports countries and recognition of the need for altitude training is also very poor. Conclusions Therefore, it is very urgent to develop altitude training for maximizing athletic performance in Korea and a lot of support and efforts are needed from the government and local governments.
Purpose The present study compared physical fitness, metabolic syndrome risk factors, and resting metabolic rate (RMR) according to body mass index (BMI) and percent body fat (%BF) in 20s females. Methods Fifty-one women in their 20s were recruited and assigned into three groups, i.e., normal group (n=18), normal weight obesity (NWO) group (n=18), and obesity group (n=15) according to BMI and %BF. Physical fitness, metabolic syndrome risk factors, and RMR were measured and compared among three groups. Results Main results were as follows: 1) Physical fitness were not significantly different among three groups. 2) Regarding 1-RM, arm curl and leg extension were significantly lower in normal group and NWO group than obesity group. Leg press was significantly lower in normal group than obesity group. 3) Regarding metabolic syndrome risk factors, there were significant differences in waist circumference, ordering from low to high such as normal, NWO, and obesity groups. Systolic blood pressure and diastolic blood pressure were significantly lower in normal group and NWO group than obesity group, while HDL-C was significantly higher in normal group than NWO group and obesity group. 4) Regarding RMR, absolute values of RMR such as VO2(㎖·min-1), RMR (Kcal·min-1), RMR (KJ·min-1), and RMR (Kcal·day-1) were significantly lower in normal group and NWO group than obesity group. On the other hand, relative value of RMR such as RMR (KJ·kg-1FW·h-1) was significantly higher in normal group than NWO group and obesity group. Conclusions It was concluded that obese women showed increased risk of metabolic syndrome and low relative RMR level, and NWO had similar problems. Active health management through physical activity and dietary control should be committed to NWO individuals because the NWO has possibility of high risk of metabolic syndrome and reduction of metabolic rate from 20s even though there was no problem in their external appearance.
