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 purpose of this manuscript was to investigate the effect of high and low speed blood flow restriction versus non-blood flow restriction isokinetic exercise on isometric muscle strength, muscle fatigue, and muscle contraction displacement. Methods The subjects were consisted of ten males without non-specific muscular skeletal disease. They were classified into four training groups: ① high speed(300°/s) without blood flow restriction, ② high speed(300°/s) under blood flow restriction, ③ low speed(90°/s) without blood flow restriction, ④ low speed(90°/s) under blood flow restriction. Before and after the intervention, all of the subjects underwent measurements of isometric quadriceps strength, muscle fatigue, and muscle contraction displacement. Results In regard to isometric quadriceps strength before & after intervention, there was no significant difference between groups. For the lactic acid measurement before & after intervention, there was a signigicant difference between groups(p<.05). Also, there was a significant difference between groups(p<.05) in muscle contraction displacement in terms of Dm but there was no significant difference between groups in terms of Tc Conclusions Isokinetic exercise with blood flow restriction had effects on lactic acid and muscle contraction displacement.
[Purpose] The purpose of this study was to examine the change of muscle damage markers after maximal eccentric exercise and to verify the difference of recovery according to ACTN3 gene polymorphism. [Methods] Fifty healthy males participated in this study. Subjects performed 25 times/1 set (total 2 set) maximal eccentric contractions of the elbow flexor muscles on a modified preacher curl machine with a between-sets rest time of 5 min. Maximal isometric contraction (MIC) was measured 6 times (pre, post, after 24 h, 48 h, 72 h and 96 h). Muscle soreness (SOR) was measured 5 times (pre, after 24 h, 48 h, 72 h and 96 h). Blood samples were collected 5 times (pre, after 24 h, 48 h, 72 h and 96 h). ACTN3 gene polymorphisms were identified using polymerase chain reaction (PCR). Data were analyzed using a 2-way repeated measure ANOVA and post hoc Bonferroni test. [Results] Analysis of ACTN3 gene polymorphism revealed the following distribution: 22% RR (n=11), 50% RX (n=25), and 28% XX (n=14). Individuals were classified into the RR homozygote group (n=11) and the X-allele group (n=39). MIC showed a significant difference between groups and interaction (p<.05). The groups differed significantly in MIC at 48 h, 72 h, and 96 h after exercise and the X-allele group decreased more than the RR homozygote group. The groups differed significantly in muscle soreness and interaction (p<.05). SOR in the X-allele group was significantly higher than in the RR homozygote group at 24 h after exercise. Although blood CK activity was lower in the RR homozygote group than in the X-allele group, but there was no significant difference between the groups (p>.05). [Conclusion] The RR homozygote group showed lower muscle strength reduction rate, muscle soreness and blood CK activity than the X-allele group. This indicates that RR individuals have a lower risk of exercise-induced muscle damage than those with an X-allele.
[Purpose] This study aimed to examine the effects of complex physical training on exercise and football performances in youth football players. [Methods] The subjects (n=16) were randomly assigned to either a complex physical training group (CPG, n=8) or a control group (CON, n=8). CPG was performed the complex physical training for 50 minute per day, and 2∼3 times per week, for 8 weeks. Exercise performance (health related physical fitness, skill related physical fitness, Y-balance and functional movement screen; FMS) and football performance (juggling, speed dribbling, shot passing, long kick and triple hop) were measured before and after 8 weeks complex physical training. [Results] Sit-up (p=0.002), sit and reach (p=0.040), 50-m run (p=0.031), side step (p=0.005), single-leg standing with eyes closed (p=0.040), plank (p=0.023), dominant composite score (p=0.002) and non-dominant composite score (p=0.005), deep squat (p=0.009), inline lunge (p=0.042), active straight leg-raise (p=0.015), rotary stability (p=0.049), total score(p=0.001), speed dribbling (p=0.030), dominant triple hop (p=0.001) and non-dominant triple hop (p=0.032) were statistical significant interactions between group and time. [Conclusion] Our findings indicate that complex physical training has beneficial effects on performance improvement of exercise and football in youth football players.
Purpose The purpose of this study is to deeply understand what high school student athletes are doing as athletes and how they are transformed into student athletes from studying and exercising simultaneously. Through this, to understand the life of student wrestlers and to provide basic data for rational improvement of school athletic department. Methods Participants of the study selected one student in the second grade and two students in the third grade at Woosu high school in metropolitan. Data was collected through in-depth interviews, participant observation, and document analysis. The collected data was analyzed using Domain Analysis and Taxonomic Analysis by Spradley(1979). To assure the credibility of the data, additional checks and analysis were conducted with the participants, and the research process was examined by experts. Moreover, the common contents of the data were included in the research results with multilateral verification. Results Woosu high school wrestling student athletes were recognized as athletes as a training life to lose their dreams, a school life to stop their work. However, since student athletes have been studying and exercising together, they have been transformed from a trainee to a motivated active, a student who is reborn in the school community, and transformed a reflective student athlete to an immature player on a daily life. Conclusion The policy of the school athletic department to study and exercise together has a positive effect on student athletes and has a good effect. The introduction and practice of this system can expect true student athletes and establish elite physical education right away.
Purpose The purpose of the study was to perform a comparative analysis of the YANG Hak Seon technique carried out by "K" athlete with the kinematical data of "Y" athlete and propose a method to improve the YANG Hak Seon technique of "K" athlete. Method The subject recruited for the study was a male athlete from Korean national team (Age: 21, height: 1.65 m, body weight: 59.6 kg, and career: 11 years). Four high - speed cameras were used to analyze the 3D motion of the YANG Hak Seon technique performed by "K" athlete. The variables selected for analysis were the velocity of COM, displacement of COM, the rotational & torsional angle of the trunk and rotational & torsional angular velocity of the trunk. The results obtained were compared to the preexisting data of the "Y" athlete (data set from the published research). Results Firstly, the horizontal displacement of the YANG Hak Seon technique of the "K" athlete was observed to be shorter along with lower vertical displacement during landing compared to “Y” athlete. In addition, the overall horizontal velocity was low and vertical velocity was not generated which rises during the BC (board contact) phase. Although the rotational angular velocity of the trunk was lower during the BC, HC (horse contact) phase and LD (landing) phase, torsional angular velocity was higher during the LD. Conclusion In order to improve the completeness of the YANG Hak Seon technique of the K player, it is necessary to enter with a fast and low posture on the footplate during the initial phase. In the BC phase, it is essential to raise the COM simultaneously while landing on the footplate and increase the rotational angular velocity of the trunk.
Purpose The purpose of this study was to analyze the effect of push-up plus exercise(PUPE) on stabilization of the scapula and to use it as basic data for shoulder rehabilitation program. Methods In this study, research papers were collected using Research Information Sharing Service(RISS) and Pub-Med Central.(PMC) as a search term for scapular stabilization, push - up plus, shoulder joint injury rehabilitation and scapular stabilization exercise. Also, it was used as basic data of literature analysis. The collected data were classified into the structure and movement of the scapula and shoulder, kinesiologic relation of the scapula and the mechanism of injury, and the effect of push-up plus Results Serratus anterior is a typical stabilizing muscle, and it forms a force couple with the upper and lower trapezius to control the movement of the scapula. The PUPE is an effective exercise method to selectively strengthen serratus anterior, which are the stabilizing muscles of the scapula, and is an exercise method that is also useful for correcting the wrong postures and movements because of hypertonus upper trapezius. In addition, various conditions such as application posture, arm position, and ground instability were suggested during PUPE. Conclusion The results of this study confirmed that PUPE is an effective program for scapula stabilization in the rehabilitation of shoulder injuries and injured patients and athletes. The PUPE will be used as a rehabilitation exercise program for patients and athletes who need rehabilitation of the shoulder joint.
Purpose The purpose of this study is to investigate the effects of grip width and hand orientation on muscle activities of upper body during the lat pull-down. Methods Eight healthy men performed the 6 grip variations (3 grip width × 2 hand orientation) using an experimentally determined load of 70% of 1 repetition maximum. Five trials were analyzed for each grip type. Participants maintained a cadence of 2-second concentric and 2-second eccentric phases. The grip widths were normalized for each individual by using their biacromial diameter (100%), and then set the grip width 50% of biacromial diameter and 150% of biacromial diameter. Surface EMG of the latissimus dorsi, pectoralis major, infraspinatus, biceps brachii, triceps brachii, rectus abdominis, erector spinae and middle trapezius was recorded, and the root mean square of the EMG was normalized, using a maximum isometric voluntary contraction. Results Latissimus dorsi showed higher muscle activities in 100% grip width than those of 50% grip width. Pectoralis major and rectus abdominis showed higher muscle activities in 50% and 100% grip width than those of 150% grip width. Middle trapezius showed higher muscle activities in 150% grip width than those of 50% grip width. Conclusions Two-way repeated measures ANOVA for each muscle revealed that latissimus dorsi and middle trapezius (the posterior muscles of trunk) showed higher muscle activities in wide grip, on the other hand, pectoralis major and rectus abdominis (the posterior muscles of trunk) showed higher muscle activities in narrow grip.
Purpose In recent years, competition among companies has become more and more important to maximize the competitiveness of companies by improving their productivity through technological innovation. Increasing competitiveness through technological innovation is becoming an essential requirement for survival of companies. In order for companies to innovate, it is necessary to spend R&D investment and the government is strengthening various policy supports to do this. Athletic equipment industry classified as manufacturing industry in sports industry. In this study, considering the fact that manufacturing industry occupies a large part of Korea's R&D investment, we compared R&D intensities with athletic equipment industry and other industries. We also examined whether R&D investment has affected firm performance. Methods The data used in the analysis were extracted from KIS-DATA with KSIC codes of companies classified as sports and athletic goods manufacturing industry in the 9th Korean Standard Industrial Classification of National Statistical Office. The analysis period is five years from 2011 to 2015 to look at the current status. Looking at the number of companies extracted by year, it was 42 in 2011, 45 in 2012, 46 in 2013, 48 in 2014, and 39 in 2015. Results Research showed that the intensity of R&D of athletic equipment industry was 1.22% in 2011, 1.63% in 2012, 1.51% in 2013, 1.53% in 2014 and 1.30% in 2015. This was lower than the manufacturing industry, which was a category of athletic equipment industry, and lower than that of similar small and medium sized enterprises. The correlation between R&D intensities and the sales growth rate of firms showed a positive correlation in 2011 and 2015, but the correlation is not strong. Conclusion R&D investment in athletic equipment industry was not actively taking place, and R&D investment did not have a significant effect on the performance of the company.
Purpose The purpose of this study was to develop the new indirect method assessing maximal oxygen uptake (VO2max) using heart rate (HR) and accelerometer during walk exercise. Methods One hundred seven participants (55 male, 52 female) performed a graded exercise test to determine VO2max and two types of 1,600 m walk exercises (fast walk and pace controlled walk). The equations for estimating VO2max was developed by stepwise multiple regression. The validity of developed equations tested through the correlation between measured VO2max and estimated VO2max, was assessed by predicted residual sum of squares, and Bland-Altman plotting. Results VO2maxwas correlated with time, and HR/activity count per minute (ACM) measured in pace controlled walk exercise at all distance (400 m, 800 m, 1,200 m, 1,600 m). The equations were valid significantly and their multiple correlation coefficients or standard estimated error were similar to that Åstrand-Rhyming cycle ergometer test or Rockport 1 mile walk test. Using HR/ACM in pace controlled walk (400 m), it was possible to estimate VO2max(R2: 0.675, %SEE: 10.7). The equation was: VO2max=121.659+6.656×Gender-0.865×Age-9.540×Time-2460.952×HR/ACM (Gender, 0=female, 1=male: Time, hundredth of a minute: HR, heart rate: ACM, activity count per minute). Conclusion Estimation equations developed in this study are considered to estimate VO2max through a shorter distance, or a lower intensity of walk exercise. It is required studies to target a wide range of ages or to develop walk test on a lower bpm.
