KARATECH: A Practice Support System Using an Accelerometer to Reduce the Preliminary Actions of Karate

Kumite is a karate sparring competition in which two players face off and perform offensive and defensive techniques. Depending on the players, there may be preliminary actions (hereinafter referred to as "pre-actions"), such as pulling the arms or legs, lowering the shoulders, etc., just before a technique is performed. Since the presence of a pre-action allows the opponent to know the timing of the technique, it is important to reduce pre-actions in order to improve the kumite. However, it is difficult for beginners and intermediate players to accurately identify their pre-actions and to improve them through practice. Therefore, this study aims to construct a practice support system that enables beginners and intermediate players to understand their pre-actions. In this paper, we focus on the forefist punch, one of kumite's punching techniques. We propose a method to estimate the presence or absence of a pre-action based on the similarity between the acceleration data of an arbitrary forefist punch and a previously prepared dataset consisting of acceleration data of the forefist punch without a pre-action. We found that the proposed method can estimate the presence or absence of a pre-action in an arbitrary forefist punch with an accuracy of 86%. We also developed KARATECH as a system to support the practice of reducing pre-actions using the proposed method. KARATECH shows the presence or absence of pre-actions through videos and graphs. The evaluation results confirmed that the group using KARATECH had a lower pre-action rate.

The effect of 10 weeks of karate training on the development of motor skills in children who are new to karate

This study investigated the effect of a 10-week karate training program on the motor skill development of 5-7-year-old children new to karate with two different test batteries. A total of 28 participants were included in the study: 18 in the Karate group and 10 in the control group. The karate group was subjected to a fundamental karate training (kihon) program consisting of 90-minute sessions four days a week for ten weeks in addition to physical education classes at their schools. In contrast, the control group did not participate in any sportive activities except physical education classes in their schools. Data were collected using the Eurofit test battery and the TGMD-2 test. In the pre-post test comparison of the anthropometric measurements of the karate group, no significant difference was found in the control group. In contrast, a significant difference was obtained in height, body mass index, and body fat percentage. In the post-test analysis of the two independent groups, there were statistically significant differences in favor of the karate group regarding height and body fat percentage (p < 0.005). In the pre-post analysis of the Eurofit test and the TGMD-2 for the karate group, all parameters showed statistically significant improvements (p < 0.001), while the control group showed no statistical difference. After comparing the karate and control groups, the Eurofit Test and TGMD-2 post-test results showed significantly higher scores (statistically significant differences) in all parameters for the karate group. In conclusion, the study shows that the 10-week karate training program positively affected the motor development of the participating children.

Older Persons Participation in Hard Martial Arts: Opportunities to Improve Psychological Well-Being? A Scoping Review

This study aims to explore the potential psychological and cognitive advantages for older individuals engaged in hard martial arts (HMA), through a comprehensive scoping review of literature up to 2023. Specifically, it examines the extent of changes in cognition, mental state, and quality of life among elderly participants of HMA. Inclusion criteria were studies conducted on healthy persons who were over 50 years of age. Only papers published in the English language were included. The search was undertaken in electronic databases and sources of grey literature. Thirteen papers with a total of 514 participants met the inclusion criteria. Improved cognition and decreased levels of anxiety and depression were emerging themes. Together, these factors contributed to the quality of life of participants. HMA was found to benefit cognitive abilities and psychological well-being, increasing quality of life more than traditional exercise alone. Findings suggested duration of training influenced change more than frequency. The limited number of studies exploring the effects of HMA on mental wellness and cognitive ability in older adults underscores the need for further research. The findings of this review suggest cognitive and quality of life improvements and reduced depression and anxiety in individuals engaging in HMA. This review serves as a foundation for soundly designed future research.

Effect of 6-week karate (kihon) and basic movement exercise on balance performance in visually impaired individuals

Today, the participation of visually impaired individuals in sports activities is essential. Because the ability to move independently starts to develop with a delay in visually impaired individuals, physical activity is necessary to compensate for developmental delay, eliminate the problem of independent movement in social life by reducing obstacle perception problems, develop self-confidence, and provide regular muscle activation and motivation to move. The study investigated the effect of 6 weeks of karate (kihon) and basic movement training on balance performance in individuals with congenital visual impairment. Fifteen visually impaired individuals aged between 10 and 14 participated in the study, and three groups were formed: experiment 1, experiment 2, and the control group. After the pre-tests were taken, the experimental groups received karate and basic movement training in addition to physical education classes for 6 weeks, while the control group received only physical education classes. When the study results were examined, there were highly significant differences between the pre- and post-test values of the groups receiving karate and basic movement training. At the same time, no progress was observed in the control group. In the post-test comparison of the karate and control groups, positive significance was found in the values of the karate group. In the same way, in the post-test comparison of the basic movement training group and the control group, positive progress was made in the basic movement training group. The post-test comparison of the basic movement training and karate groups was the same. As a result, it was concluded that basic movement training and karate exercises applied for 6 weeks positively affected the balance development in visually impaired individuals aged 10-14 years. No difference was found between the exercise protocols regarding effectiveness, and no improvement was observed in individuals who did not participate in any exercise.

Personality Traits vs. Sports Classes of Polish Representatives in Junior Sports Acrobatics

The aim of this paper was to determine the influence of adolescence, training discipline, and training regime on the personality formation of adolescent sports acrobats. Therefore, the purpose of this paper was to study the relationship between the personality traits and the sports classes of Polish junior sports acrobatics representatives. The respondents (N = 90) were juniors aged 18-19 and were divided into three samples: (1) n = 30 Polish representatives in sports acrobatics with a first or master sports class; (2) n = 30 kata athletes from Kyokushin karate and Shotokan karate as a reference sample from another sports discipline with gymnastic movement expression; (3) n = 30 high school students as a reference sample of non-athletic persons. The Big Five model was used, and the NEO-FFI personality questionnaire was used as a research tool. For the analyses of basic descriptive statistics, the Kruskal-Wallis test and Mann-Whitney test were performed to determine statistical significance (α = 0.05). It was noted that all athletes (the first and second samples) had personality traits at the same levels: low neuroticism, high extraversion, moderate openness to experience and agreeableness, and high conscientiousness in relation to non-athletes. In contrast, there were differences among the subjects in personality traits, except for agreeableness. Among the sports acrobats, master-class athletes showed lower neuroticism, greater openness to experience, lower agreeableness, and greater conscientiousness in relation to first-class athletes. It was found that there were differences between the personality traits and sports classes of junior sports acrobatics representatives in Poland in the four Big Five dimensions. But in general, sports acrobats and karate athletes had personality traits at similar levels, and at the same time, different from non-training people.

Headguard use in combat sports: position statement of the Association of Ringside Physicians

Headguard use is appropriate during some combat sports activities where the risks of injury to the face and ears are elevated. Headguards are highly effective in reducing the incidence of facial lacerations in studies of amateur boxers and are just as effective in other striking sports. They should be used in scenarios - especially sparring prior to competitions - where avoidance of laceration and subsequent exposure to potential blood-borne pathogens is important. Headguards are appropriate where avoidance of auricular injury is deemed important; limited data show a marked reduction in incidence of auricular injury in wrestlers wearing headguards.Headguards should not be relied upon to reduce the risk of concussion or other traumatic brain injury. They have not been shown to prevent these types of injuries in combat sports or other sports, and human studies on the effect of headguards on concussive injury are lacking. While biomechanical studies suggest they reduce linear and rotational acceleration of the cranium, changes in athlete behavior to more risk-taking when wearing headguards may offset any risk reduction. In the absence of high-quality studies on headguard use, the Association of Ringside Physicians recommends that further research be conducted to clarify the role of headguards in all combat sports, at all ages of participation. Furthermore, in the absence of data on gender differences, policies should be standardized for men and women.

"We missed the psychological support": A case study about the preparation of the Brazilian bronze medal kata team for the 2019 Pan American Games

Purpose

The main aim of the study was to describe the key factors involved in the preparation process of the Brazilian bronze medal kata team for the 2019 Pan American Games, focusing on the athletes' perceptions.

Methods

Three male athletes from the Brazilian team performed a semistructured interview to identify the following topics: specific time for preparation, training organization, supplementary support, and perception and suggestion about the efficiency of the preparation process.

Results

Data from interviews were gathered and coded, and the major themes were summarized as follows after performing content analysis of the data: (a) technical and tactical training took the major part of the preparation; (b) the high level of the coaches helped the team to reach the technical quality of the kata; (c) better psychological support during the preparation could improve the athletes' performance during the training and competition; and (d) the lack of financial support compromised the commitment of the athletes during the training routine.

Conclusion

We concluded, based on the athletes' perception, that the most positive factor during preparation for a major competition was the high amount of time focused on technical-tactical training. Even with limitations to performing the physical training, the athletes recognized the importance of the physical component, to increase performance. Financial and psychological support could have helped the team to reach a better result (gold medal) attenuating the training distress.

Examining karate and football perceptions and their links with athlete engagement and quality of life

The importance of perceptions as determinants of people's behavior has been well-established, but little is known about athletes' perceptions of their sport and the links of these perceptions with other correlates. In this study, we compared karate (n = 51) and football (n = 49) athletes' perceived benefits and aggressiveness risks from their sports and examined whether these perceptions predicted athletes' engagement and quality of life (QoL). Participants completed perception measures of karate and football, and engagement and QoL measures. Results showed that karateka perceived more benefits and fewer risks in karate than football, but footballers generally perceived equal benefits and risks in both sports. Both athlete groups perceived similar physical and psychological benefits in their own sport, but deemed physical benefits as prominent outcomes in the other sport. Notably, karateka's perceived benefits about karate predicted engagement directly and QoL indirectly via vigor. Overall, karate athletes' perceptions seemed to be relevant to experiencing fulfillment in training and general well-being.

Effects of Core Training in Physical Fitness of Youth Karate Athletes: A Controlled Study Design

This study aimed to analyse the impact of an 8-week core strength training (CST) programme in youth karate practitioners on core endurance, agility, flexibility, sprinting, jumping, and kick performance. This study followed a randomized parallel design. Twenty-nine participants (age: 12.86 ± 0.81 years old; height: 152.55 ± 10.37 cm; weight: 42.93 ± 8.85 kg) were allocated to a CST programme (n = 16) performed thrice weekly or to a control group (n = 13) only performing the sport-specific (karate) training. Participants were assessed three times (baseline, mid and post-intervention) for the following tests: (i) flexor endurance test (FET); (ii) back extensor test (BET); (iii) lateral musculature test (LMT); (iv) flexibility; (v) chance of direction (COD); (vi) countermovement jump (CMJ); (vii) back muscle strength (BMS); (viii) horizontal jump (LJ); (ix) sprint test; and (x) karate kick test (KKT). Between-group analysis revealed significant advantages for the CST group on the FET (p < 0.001), BET (p < 0.001), LMT (p < 0.001), 20 m sprint (p = 0.021) and KKT for right (p < 0.006) and left (p < 0.020) legs. No significant differences were found between groups in the remaining physical fitness variables (p > 0.05). The within-group changes revealed significant improvements in the CST group at flexibility (p = 0.002), COD (p < 0.001), CMJ (p < 0.001), BMS (p < 0.002), 20 m sprint (p = 0.033), and KKT (p < 0.001). In addition, within-group changes in the control group were also significant in flexibility (p = 0.024) and right kick (p < 0.042). We conclude that the CST programme improves core endurance and karate kick performance; however, it is not effective enough for other physical performance parameters in KR practitioners.

Motor Competence in Individuals with Down Syndrome: Is an Improvement Still Possible in Adulthood?

In children, motor competence (MC) and the amount of physical activity are tightly interconnected. In adults with Down syndrome (DS), MC has been poorly addressed, resulting in a limited understanding of the possibility to improve MC over time. Here, we aim to: (1) investigate MC in adults with DS by comparing them with a group of typically developed peers and (2) verify the effect of an adapted karate program on MC. Adults with DS (DSG; n = 57) and typically developed adults (TDG; n = 21) performed the Test of Gross Motor Development version 3 (TGMD-3). The total TGMD-3 score (^TOTTGMD-3), the locomotor (^LOCTGMD-3), and object control (^OBJTGMD-3) scores were computed. After a 40 week adapted karate program, DSG (n = 37) underwent the post-training TGMD-3 assessment. Compared to TDG, DSG showed lower ^TOTTGMD-3 (DSG: 45.5 ± 17.3; TDG: 77.3 ± 9.5), ^LOCTGMD-3 (DSG: 22.2 ± 10.0; TDG: 36.2 ± 7.6) and ^OBJTGMD-3 (DSG: 23.3 ± 10.9; TDG: 41.1 ± 5.6). After the training, ^TOTTGMD-3, ^LOCTGMD-3 and ^OBJTGMD-3 increased by 35.6%, 30.0% and 40.7%, respectively. Our results suggest that MC acquisition does not evolve into a mature form in adulthood in individuals with DS. Moreover, a brief exposure to an adapted karate program induces an increase in motor competence in DS, even in adulthood.

Toward Modeling Psychomotor Performance in Karate Combats Using Computer Vision Pose Estimation

Technological advances enable the design of systems that interact more closely with humans in a multitude of previously unsuspected fields. Martial arts are not outside the application of these techniques. From the point of view of the modeling of human movement in relation to the learning of complex motor skills, martial arts are of interest because they are articulated around a system of movements that are predefined, or at least, bounded, and governed by the laws of Physics. Their execution must be learned after continuous practice over time. Literature suggests that artificial intelligence algorithms, such as those used for computer vision, can model the movements performed. Thus, they can be compared with a good execution as well as analyze their temporal evolution during learning. We are exploring the application of this approach to model psychomotor performance in Karate combats (called kumites), which are characterized by the explosiveness of their movements. In addition, modeling psychomotor performance in a kumite requires the modeling of the joint interaction of two participants, while most current research efforts in human movement computing focus on the modeling of movements performed individually. Thus, in this work, we explore how to apply a pose estimation algorithm to extract the features of some predefined movements of Ippon Kihon kumite (a one-step conventional assault) and compare classification metrics with four data mining algorithms, obtaining high values with them.

Somatotype Profiles of Montenegrin Karatekas: An Observational Study

Competitive karate activity involves numerous factors affecting performance in sport. Physical structure and somatotype is considered to be one of them. This study aimed to determine whether there are differences between karate athletes in five male and five female official weight categories in different anthropometric measurements and to determine the somatotype profiles of athletes divided by weight categories. This study consisted of a total of 27 male karate athletes (21.88 ± 4.66 years) and 24 female karate athletes (20.29 ± 3.14 years). Measurements were taken in April 2020. Athletes are classified into official weight categories according to World Karate Federation rules. Somatotypes were calculated using anthropometry. One-way analysis of variance and Tukey’s post hoc tests were used for statistical analysis to compare group differences regarding weight categories. Anthropometric parameters were highest in the heaviest categories compared to lighter categories. All male subjects were endomorphic mesomorph, except for category <84 kg, which was endomorphic ectomorphs. Somatotype analysis of male categories found a difference between the <75 kg and <84 kg in endomorphy. In mesomorphy, there is no difference between categories. Perceiving ectomorphy, there is a significant difference between the first category and the >84 kg. Profiling female athletes, three different types of somatotypes were obtained concerning the weight category. The lightest weight category was predominantly endomorphic ectomorphs, and two weight categories were ectomorphic endomorphs (<61 kg and <68 kg), and the other two weight categories were endomorphic mesomorphs (<55 kg and >68 kg). Somatotype differences in the female karate athletes were observed only in the ectomorphy components, between <50 kg and <61 kg. The present study points to how the somatotypes profiles of karate athletes differ between weight categories.

Weight Loss Strategies in Male Competitors of Combat Sport Disciplines

Background and objective: The use of suboptimal weight loss strategies in order to reach specific weight ranges as observed in combat sport disciplines can give rise to severe health problems. However, particular aspects regarding management of weight category comparing three sport disciplines remain to be investigated. Therefore, the aim of the present study was to obtain information regarding the weight loss strategies that competitors performed before a tournament. Materials and Methods: This article describes the most common dietary-nutritional strategies used by 140 national university male competitors of judo (n = 52), karate (n = 40) and taekwondo (n = 48) in order to achieve a specific weight, according to the rapid weight loss questionnaire (RWLQ) and the EAT-27 questionnaire. Results: Around 50% of participants were not involved in a weight loss process. Among the remaining participants, we considered three periods for weight reduction: less than 1 week (35% in judo, 8% in karate and 19% in taekwondo), less than 1 month (17% in judo, 15% in karate and 26% in taekwondo) and more than 1 month (0% in judo, 5% in karate and 21% in taekwondo). Severe fasting, focused on food/water restriction, was the most commonly used strategy, being more frequent in judo players. Light weight judo practitioners generally lost 2–5 kg before the contest. One third of participants avoided carbohydrate consumption when performing food restriction. Finally, individuals that reduced weight in the last week seemed to develop an unhealthy psychological relationship with food. Conclusion: All these aspects could be particularly relevant, providing information regarding how competitors manage basic nutritional concepts that guide dieting strategies. This information is relevant to prepare future educational interventions in the area of nutrition for competitors, coaches and technical staff.

Observational Analysis of Lateral Preference in Kumite Initiation: A Starting Point in the Longitudinal Programming of Formative Karate

We used observational methodology to analyze lateral conditioning in the technical-tactical performance of high level 8-9-year-old karatekas, specifically in relation to the guard action that supports the technical action and the body segment with which it is performed. We designed an ad hoc observation instrument to analyze lateral preference in the technical-tactical actions that take place during the kumite. We relied on LINCE software for data registration, and we found good inter-observer reliability, calculated with Cohen's Kappa coefficient. Generalizability Theory supported the homogeneity of the behavior deployed by these combatants. Our results represent a starting point in the longitudinal programming of karate. By relating our results and those of other studies that have addressed lateral performance in formative karate in the kumite modality, we are able to draw a roadmap of a karateka's path towards the equilaterality that is inherent in an elite competitor: (a) the 8-9 year old karateka must overcome a conditioned lateral prevalence by adopting a forward non-dominant leg guard so as to then attack with the dominant body segment; (b) the eqilateral use of the right or left fist must occur later, between the 12-13 year age group and the senior category; and (c) there will then be less decisive lateral conditioning in the execution of offensive leg techniques.

Aggression Dimensions Among Athletes Practising Martial Arts and Combat Sports

Purpose: The main aim of the research was to analyse aggression dimensions among athletes practising martial arts and combat sports.

Material and Methods: There were 219 respondents. The Buss and Perry Aggression Questionnaire (BPAQ) in the Polish adaptation by Siekierka was applied.

Results: Martial arts apprentices turned out to present a statistically significantly lower level of hostility (p < 0.001) and of the general aggression index (p = 0.04) than combat sports athletes. It turned out that lower level of aggression was noted in female participants (physical aggression (p < 0.001), verbal aggression (p = 0.004), hostility (p < 0.001), and the general aggression index (p < 0.001). Analysis revealed that the training experience and the training rank did not differentiated the level of the respondents' particular aggression dimensions.

Conclusions: It would be advisable to perform parallel analyses in other areas of Poland and take into account the respondents' education and place of residence.

Use of IMU in Differential Analysis of the Reverse Punch Temporal Structure in Relation to the Achieved Maximal Hand Velocity

To achieve good performance, athletes need to synchronize a series of movements in an optimal manner. One of the indicators used to monitor this is the order of occurrence of relevant events in the movement timeline. However, monitoring of this characteristic of rapid movement is practically limited to the laboratory settings, in which motion tracking systems can be used to acquire relevant data. Our motivation is to implement a simple-to-use and robust IMU-based solution suitable for everyday praxis. In this way, repetitive execution of technique can be constantly monitored. This provides augmented feedback to coaches and athletes and is relevant in the context of prevention of stabilization of errors, as well as monitoring for the effects of fatigue. In this research, acceleration and rotational speed signal acquired from a pair of IMUs (Inertial Measurement Unit) is used for detection of the time of occurrence of events. The research included 165 individual strikes performed by 14 elite and national-level karate competitors. All strikes were classified as slow, average, or fast based on the achieved maximal velocity of the hand. A Kruskal–Wallis test revealed significant general differences in the order of occurrence of hand acceleration start, maximal hand velocity, maximal body velocity, maximal hand acceleration, maximal body acceleration, and vertical movement onset between the groups. Partial differences were determined using a Mann–Whitney test. This paper determines the differences in the temporal structure of the reverse punch in relation to the achieved maximal velocity of the hand as a performance indicator. Detecting the time of occurrence of events using IMUs is a new method for measuring motion synchronization that provides a new insight into the coordination of articulated human movements. Such application of IMU can provide additional information about the studied structure of rapid discrete movements in various sporting activities that are otherwise imperceptible to human senses.

Football

Little is known about people's perceived benefits and risks of sports, despite their role in shaping people's intentions to engage in them. Here, we developed and tested a scale to measure perceived physical, emotional, cognitive, and social benefits as well as aggression-related risks of karate and football. Additionally, we compared these perceptions within and between these two sports, as well as among undergraduates with current/former participation in different types of physical activity (viz., martial artists, team sports players, participants in other types of physical activity, and non-participants). After a literature review, we created a 5-factor scale with 20 items administered to 184 undergraduates, along with questions about physical activity participation. After removing five items, confirmatory factor analyses supported the factor structure of the scale. Factor loadings and reliability indices were acceptable, though less than desirable results were found concerning the average variance extracted of all benefits dimensions and the reliability of the social benefits dimension. Analyses of variance showed that: (a) physical benefits were seen as the salient outcomes of karate and football, though martial artists perceived karate's physical, emotional, and social benefits to the same extent; (b) in comparison to football, karate was perceived to bring more emotional and cognitive benefits and to entail less aggressiveness risks; (c) karate and football perceptions varied as a function of participant's involvement in physical activity. This study presents a promising instrument to gather information on people's perceptions about karate and football, which can be used to foster people's engagement in them.

The Level of Aggressiveness During Karate Practice of Inmates in Correctional Settings

Karate is known to enhance cognitive functioning, emotional well-being, and self-regulation and to contribute to an overall behavior rehabilitation process. However, few data are available on the impact of practicing karate in adult prison inmates. The main objective of this research was to evaluate aggressive behavior, comparing prison inmates and club practitioners during karate practice. The level of aggressiveness was rated by observers during defined elements and training situations in karate classes held in France. Data were collected during 77 observations of 75 prison inmates (55 male and 20 female) in a prison setting, and 188 observations of 117 club practitioners (80 male and 37 female) in a club setting over a period of 26 months. Licit aggressiveness was graded by observers during launched actions, kiais, and bows, and the practice level (belts) was also considered. Interrater reliability of the observational measure was highly acceptable (Cohen κ = 1). Comparisons between female and male prison inmates and club practitioners were made using the non-parametric Mann–Whitney U-test for independent samples. The results revealed that a higher level of aggressiveness was observed in both male and female club practitioners during launched actions and kiais than in prison inmate practitioners (p < 0.001, small effect size). However, prison inmates (of both genders) showed a higher level of aggressiveness during bows (p < 0.001, medium effect size). While the analyses showed no significant differences between genders, the level of karate practice was associated with distinct changes. Significant differences in observed aggressiveness were present only in beginners and in those with a low level of karate practice, whereas no differences in aggressiveness between prison or club practitioners were observed during karate practice in those with a high level of karate practice (black belt). However, these results must be interpreted with caution as there was no way to control the multiple factors that might also affect inmate behaviors in a correctional setting. We suggest that karate practice in prison may positively contribute to interactional behaviors.

Assessing the Effects of Kata and Kumite Techniques on Physical Performance in Elite Karatekas

This study aimed at assessing physical performance of elite karatekas and non-karatekas. More specifically, effects of kumite and kata technique on joint mobility, body stability, and jumping ability were assessed by enrolling twenty-four karatekas and by comparing the results with 18 non-karatekas healthy subjects. Sensor system was composed by a single inertial sensor and optical bars. Karatekas are generally characterized by better motor performance with respect nonkaratekas, considering all the examined factors, i.e., mobility, stability, and jumping. In addition, the two techniques lead to a differentiation in joint mobility; in particular, kumite athletes are characterized by a greater shoulder extension and, in general, by a greater value of preferred velocity to perform joint movements. Conversely, kata athletes are characterized by a greater mobility of the ankle joint. By focusing on jumping skills, kata technique leads to an increase of the concentric phase when performing squat jump. Finally, kata athletes showed better stability inclosed eyes condition. The outcomes reported here can be useful for optimizing coaching programs for both beginners and karatekas based on the specific selected technique.

Strategy and Decision Making in Karate

Karate will be included in the 2020 Summer Olympics in Tokyo as an additional sport. The inner logic of this activity includes a specific scoring system and way of modeling. Three hundred and nine bouts were observed in the competition context, which resulted in new perspectives on training and competition. The scoring of punches (43.7% of total scored points) and face kicks (37.9%) appears to be more significant (p ≤ 0.01) than that of body kicks (15.3%, p ≤ 0.01) and leg-sweeping (3.1%, p = 0.31). Penalties appear to be very significant and associated with victory when “scored” by the competitor against himself or herself (p ≤ 0.01). Competitors must score points and penalties. This zero-sum game induces a simple rivalry, whose purpose is domination and which must rely on a predefined strategy and initiative. Karatekas have to make decisions, such as when taking the risk to score points and penalties, whether or not they lead the score. Karatekas may decide to expose or protect themselves, create situations, or simply remain realistic and adhere to the plan. The question of decision making, which is central to this work, forces us to focus our future work on the notions of expectations and self-fulfilling prophecies.

Time-Loss Injuries in Karate: A Prospective Cohort Study of 4 Consecutive World Karate Championships

Background:

Prospective studies on injuries in martial arts competitions are scarce, especially those involving time-loss injuries. The upsurge of karate athletes competing in top-level karate competitions warrants elucidation of the time-loss injury risk.

Purpose:

To determine the time-loss injury proportion and incidence rate, describe the injury pattern among elite senior karate athletes, and compare the risk of time-loss injuries in male versus female athletes and in individual (ie, weight categories) versus team competitions (free-weight category).

Study Design:

Descriptive epidemiology study.

Methods:

Data were collected at 4 consecutive World Karate Championships (2010, 2012, 2014, and 2016). Injury incidence rates were calculated per 1000 athlete-exposures (IIR_AE) and per 1000 minutes of exposure (IIR_ME), with 95% CIs. Subgroups were compared by calculating their rate ratios with 95% CIs.

Results:

A total of 506 injuries were recorded, of which 51 were time-loss injuries (10%). The overall time-loss injury rate was significantly lower for female versus male athletes and slightly lower for team versus individual competitions. Overall, 1.4% of all athletes sustained a time-loss injury, and the IIR_AE and IIR_ME were 5.13 (95% CI, 3.82-6.74) and 1.98 (95% CI, 1.47-2.60), respectively. The most common type of time-loss injury was fracture (41%), followed by dislocation (20%) and concussion (12%).

Conclusion:

The time-loss injury incidence rate for top-level karate competitions found in this prospective study was relatively low. Comprehensive knowledge about the incidence of time-loss injuries during karate competitions represents an essential basis to develop effective strategies for injury prevention. Thus, the introduction of a uniform injury surveillance system in martial arts is of utmost importance.

Sense of Coherence and Connectedness to Nature as Predictors of Motivation for Practicing Karate

Background: Physical activity yields exceptionally positive results when it takes place out in the open air, in contact with nature. Both contact with nature and practicing sport constitute a certain kind of philosophy of life and living by its rules plays a vital role in positive mental health―understood as maintaining a high sense of coherence. Martial arts are examples of sports that are rooted in a philosophy. The goal of this study was to explore the links between a sense of coherence and connectedness to nature in the context of motivations for practicing karate. Methods: A total of 127 practitioners of karate were examined using the Inventory of Physical Activity Objectives (IPAO), the Sense of Coherence Questionnaire, and the Connectedness to Nature Scale. Results: The most important objective for women training karate was a fit, shapely body, and for men the most important objective was physical fitness. Connectedness to nature had the strongest positive relationship with the measure of physical fitness (in both genders). A sense of comprehensibility increased men’s motivational conflict, whereas, in women, this IPAO dimension was positively related to feeling emotionally connected to the natural world. Connectedness to nature was related to motivational conflict positively in women and negatively in men. Feeling emotionally connected to the natural world correlated with a sense of comprehensibility, a sense of manageability, and a sense of meaningfulness. Sense of comprehensibility and sense of meaningfulness tended to increase with age. Conclusions: Understanding both the natural environment and the utility of setting sport-related goals led to increasing one’s efforts on the way to both successes and defeats, and, most of all, overcoming one’s weaknesses.

Karate and Dance Training to Improve Balance and Stabilize Mood in Patients with Parkinson's Disease: A Feasibility Study

The present pilot study investigated the effect of karate (according to the rules of the German Karate Federation) and dance training compared to an inactive control group in patients with Parkinson's disease (PD). 65 patients were recruited. At the end, 37 patients completed the post-test. From those 37 patients, 16 had chosen the karate training, 9 the dance training and 12 the waiting control group. Before and after the whole training phase cognitive performance, emotional well-being and balance were measured. The results showed that both, karate and dance training groups, improved balance. Furthermore, the mood dropped only in the waiting control group receiving no training at all, whereas it remained stable in patients who attended the karate and dance group. The training adherence was higher in the karate than the dance group indicating a high acceptability in PD patients for karate. In sum, karate can have the same positive effects as dance for PD patients. Further studies with larger samples and more rigorous methodologies are required to investigate the reported effects in more detail.

Human Actions Analysis: Templates Generation, Matching and Visualization Applied to Motion Capture of Highly-Skilled Karate Athletes

The aim of this paper is to propose and evaluate the novel method of template generation, matching, comparing and visualization applied to motion capture (kinematic) analysis. To evaluate our approach, we have used motion capture recordings (MoCap) of two highly-skilled black belt karate athletes consisting of 560 recordings of various karate techniques acquired with wearable sensors. We have evaluated the quality of generated templates; we have validated the matching algorithm that calculates similarities and differences between various MoCap data; and we have examined visualizations of important differences and similarities between MoCap data. We have concluded that our algorithms works the best when we are dealing with relatively short (2–4 s) actions that might be averaged and aligned with the dynamic time warping framework. In practice, the methodology is designed to optimize the performance of some full body techniques performed in various sport disciplines, for example combat sports and martial arts. We can also use this approach to generate templates or to compare the correct performance of techniques between various top sportsmen in order to generate a knowledge base of reference MoCap videos. The motion template generated by our method can be used for action recognition purposes. We have used the DTW classifier with angle-based features to classify various karate kicks. We have performed leave-one-out action recognition for the Shorin-ryu and Oyama karate master separately. In this case, 100% actions were correctly classified. In another experiment, we used templates generated from Oyama master recordings to classify Shorin-ryu master recordings and vice versa. In this experiment, the overall recognition rate was 94.2%, which is a very good result for this type of complex action.

Fatigue-related changes in technique emerge at different timescales during repetitive training

Training consisting of numerous repetitions performed as closely as possible to ideal techniques is common in sports and every-day tasks. Little is known about fatigue-related technique changes that emerge at different timescales when repeating complex actions such as a karate front kick. Accordingly, 15 karatekas performed 600 kicks (1 pre-block and 9 blocks). The pre-block comprised 6 kicks (3 with each leg) at maximum intensity (K-100%). Each block comprised 60 kicks (10 with each leg) at 80% of their self-perceived maximum intensity (K-80%) plus 6 K-100%. In between blocks, the participants rested for 90 seconds. Right leg kinematics (peak joint angles, peak joint angular velocities, peak joint linear resultant velocities, and time of occurrence of peaks) and kick duration corresponding to the K-80% were measured resulting in numerous variations with fatigue. At the timescale of tens of seconds, the changes involved variables that were related to velocity of execution (slowed down), while variables related to movement form were hardly affected. At the timescale of tens of minutes, the opposite results were observed. These findings challenge the long-standing rationale underlying repetitive training, suggesting instead that such involuntary variations in technique might play a crucial role in motor skill training.

Effects of Karate Fights on Achilles Tendon Stiffness Measured by Myotonometry

The aim of the study was to investigate the influence of karate fights on Achilles tendon stiffness in karate competitors. Eleven male karate fighters participated in the present study. A handheld MyotonPRO device (MyotonPRO, Myoton Ltd, Estonia) was applied to measure Achilles tendon stiffness in karate fighters. The Achilles tendon was tested 5 cm above the tuber calcanei. Stiffness measurements were performed before and after eight sparring fights. Each fight lasted 2 min and was separated by a 2 min rest period. Achilles tendon stiffness for the dominant leg increased significantly from before fights (751.57 ± 123.493 N/m) to immediately after fights (809.43 ± 160.425 N/m) (p = 0.012). Presented results should be used by strength and conditioning coaches in training programs as a way to decrease the risk of injury.

Effects of Karate Training Versus Mindfulness Training on Emotional Well-Being and Cognitive Performance in Later Life

In a randomized controlled trial, we investigated the effects of karate versus a mindfulness-based stress reduction (MBSR) intervention on well-being and cognitive functioning in older adults. Fifty-five adults (52-81 years old) participated in twice-weekly karate versus MBSR sessions or no training for 8 weeks. In pre- and postassessments, subjective well-being, health, cognitive functioning, and chronic stress were measured. Preassessment hair cortisol served as physiological stress marker. The results showed an improvement for the karate group, but not the MBSR and control group, in subjective mental health and anxiety as well as cognitive processing speed. The MBSR group showed by trend as a decrease in stress. No significant correlation between preassessment hair cortisol and postassessment outcomes could be established. But the higher the level of baseline self-reported perceived stress, the higher the increase in depression, anxiety, and chronic stress. Generally, it can be assumed that karate and MBSR showed only small training effects concerning the assessed emotional and cognitive parameters.

Martial arts intervention decreases pain scores in children with malignancy

Background

Martial arts intervention in disease has been mostly limited to adult inflammatory, musculoskeletal, or motor diseases, where a mechanical intervention effects positive change. However, the application and benefit to pain management in childhood malignancy are not well described. Here, we assess the effects of defined martial arts intervention in children with cancer with respect to their pain perception and management.

Methods

Sixty-four children with childhood malignancies were enrolled in a martial arts program, which encompassed both meditation and movement modalities. Pain scores (0–10) were recorded pre- and post- 1-hour session intervention. Pain scores were crossed by total visits and tabulated by whether participant pain reduced at least 1 unit, stayed the same, or increased in intensity immediately after (post) participation session. Differences in pain scores were further compared by age and sex.

Results

Prepain and postpain scale data were measured for 64 participants, 43 males (67.2%) and 21 females (32.8%), ranging from 3 years to 19 years. Preintervention and postintervention data were obtained for 223 individual session visits. Mean number of patient participation visits was 1.8±1.6 (range one to nine visits). Of 116 individual measured sessions where the participants began with a pain score of at least 1, pain intensity reduced ≥1 unit in 85.3% (99/116) of visits, remained the same in 7.8% (9/116), and increased in 6.9% (8/116). For the majority (96.3%; 77/80) of sessions, participants began with a prepain intensity score of at least 5–10 with reduction in pain intensity following the session. The overall mean pain score presession visit was reduced bŷ40% (pre: 5.95±2.64 and post: 3.03±2.45 [95% CI: 2.34–3.50]; P≤0.001). Median pain intensity scores had greater reductions with increased age of participants (3–6 years [–1], 7–10 years [–2], 11–14 years [–3], and 15–19 years [–4]).

Conclusion

Martial arts intervention can provide a useful modality to decrease pain in childhood cancer, with greater effect achieved with higher baseline pain scores and patient age. Martial arts intervention may improve patient compliance with respect to medical and surgical management, thus reducing disease morbidity and health care costs.

Can height categories replace weight categories in striking martial arts competitions? A pilot study

In most combat sports and martial arts, athletes compete within weight categories. Disordered eating behaviors and intentional pre-competition rapid weight loss are commonly seen in this population, attributed to weight categorization. We examined if height categories can be used as an alternative to weight categories for competition, in order to protect the health of athletes.

Height and weight of 169 child and adolescent competitive karate athletes were measured. Participants were divided into eleven hypothetical weight categories of 5 kg increments, and eleven hypothetical height categories of 5 cm increments. We calculated the coefficient of variation of height and weight by each division method. We also calculated how many participants fit into corresponding categories of both height and weight, and how many would shift a category if divided by height.

There was a high correlation between height and weight (r = 0.91, p<0.001). The mean range of heights seen within current weight categories was reduced by 83% when participants were divided by height. When allocating athletes by height categories, 74% of athletes would shift up or down one weight category at most, compared with the current categorization method.

We conclude that dividing young karate athletes by height categories significantly reduced the range of heights of competitors within the category. Such categorization would not cause athletes to compete against much heavier opponents in most cases. Using height categories as a means to reduce eating disorders in combat sports should be further examined.

An 18-month Follow-up of Anger in Female Karate Athletes

OBJECTIVE

The aim of this study was to evaluate changes of anger scores in female karate athletes during 18 months, and to compare anger scores in adolescents who continue or stop training karate.

METHOD

The sample consisted of 18 female elite karate athletes, practicing modern style of karate. To measure anger and its subscales, participants were asked to complete "Adolescent Anger Rating Scale" (AARS) questionnaire in both stages of the study. Athletes were divided in to two groups of "stayer" (n=12) and "quitter" (n=6) if they continued practicing karate or stopped it, respectively. In order to study the changes of anger score with time, paired T test was used.

RESULTS

In analysis of changes in anger scores with time, there was a statistically significant increase in instrumental anger (p=0.001) and non-significant increase in other anger scores among 14-year-old girls who continued practicing karate.

CONCLUSION

Increased instrumental anger in female karate athletes could be due to the impact of participation in a combative sport. However, the results should be interpreted cautiously due to limitations of the study.

Anthropometric and physical performance profiles of elite karate kumite and kata competitors

Karate tournaments consist of two equally important karate disciplines: the kumite and kata competitions. Due to being based both on the distinctive selection of movement techniques and their kinematic and kinetic patterns, we hypothesized that the elite kumite and kata competitors could differ regarding their anthropometric and physical performance profiles. Thirty-one senior male karate competitors of the national karate team (kumite n = 19; kata n = 12) participated in this study. The tests applied included both the assessment of anthropometric (body height, mass and body mass index) and the following physical performance measurements: the adductor and hamstring flexibility (sideward leg splits test), speed and acceleration (20-m sprint test with 10-m acceleration time), explosive power (countermovement and standing triple jump), agility (“T”- test) and aerobic endurance (20-m multistage shuttle run test). The kumite competitors revealed a larger body size through body height (p = 0.01) and mass (p = 0.03), while the differences in body composition were non-significant. The kumite competitors also demonstrated higher acceleration (p = 0.03) and explosive power (standing triple jump; p = 0.03). A 6-7° higher flexibility of the kata competitors remained somewhat below the level of significance (p = 0.09). The findings could be interpreted by the distinctive differences in the movement techniques. Specifically, a higher explosive power could be beneficial for kumite, while both a smaller stature and higher flexibility (particularly of the lower extremity) could be important for the exceptionally low postures of the kata competitors. Although further elucidation is apparently needed, the obtained finding could be of importance for both the early selection and training of karate competitors.

Effect of adapted karate training on quality of life and body balance in 50-year-old men

BACKGROUND

Aging is associated with a decrease in physical skills, sometimes accompanied by a change in quality of life (QOL). Long-term martial arts practice has been proposed as an avenue to counter these deleterious effects. The general purpose of this pilot study was to identify the effects of an adapted karate training program on QOL, depression, and motor skills in 50-year-old men.

METHODS AND DESIGN

Fifteen 50-year-old men were enrolled in a one-year prospective experiment. Participants practiced adapted karate training for 90 minutes three times a week. Testing sessions, involving completion of the MOS 36-item Short Form Health Survey (SF36) and Beck Depression Inventory, as well as motor and effort evaluation, were done at baseline, and six and 12 months.

RESULTS

Compared with baseline, participants had better Beck Depression Inventory scores after one year of karate training (P < 0.01) and better perception of their physical health (P < 0.01), but not on the mental dimension (P < 0.49). They also improved their reaction time scores for the nondominant hand and sway parameters in the eyes-closed position (P < 0.01).

CONCLUSION

Regular long-term karate practice had favorable effects on mood, perception of physical health confirmed by better postural control, and improved performance on objective physical testing. Adapted karate training would be an interesting option for maintaining physical activity in aging.

Comparison of two variants of a kata technique (unsu): the neuromechanical point of view

The objective of this work was to characterize from a neuromechanical point of view a jump performed within the sequence of Kata Unsu in International top level karateka. A modified jumping technique was proposed to improve the already acquired technique. The neuromechanical evaluation, paralleled by a refereeing judgment, was then used to compare modified and classic technique to test if the modification could lead to a better performance capacity, e.g. a higher score during an official competition. To this purpose, four high ranked karateka were recruited and instructed to perform the two jumps. Surface electromyographic signals were recorded in a bipolar mode from the vastus lateralis, rectus femoris, biceps femoris, gluteus maximus, and gastrocnemious muscles of both lower limbs. Mechanical data were collected by means of a stereophotogrammetric system and force platforms. Performance was associated to parameters characterizing the initial conditions of the aerial phase and to the CoM maximal height. The most critical elements having a negative influence on the arbitral evaluation were associated to quantitative error indicators. 3D reconstruction of the movement and videos were used to obtain the referee scores. The Unsu jump was divided into five phases (preparation, take off, ascending flight, descending flight, and landing) and the critical elements were highlighted. When comparing the techniques, no difference was found in the pattern of sEMG activation of the throwing leg muscles, while the push leg showed an earlier activation of RF and GA muscles at the beginning of the modified technique. The only significant improvement associated with the modified technique was evidenced at the beginning of the aerial phase, while there was no significant improvement of the referee score. Nevertheless, the proposed neuromechanical analysis, finalized to correlate technique features with the core performance indicators, is new in the field and is a promising tool to perform further analyses. Key PointsA quantitative phase analysis, highlighting the critical features of the technique, was provided for the jump executed during the Kata Unsu.Kinematics and neuromuscular activity can be assessed during the Kata Unsu jump performed by top level karateka.Neuromechanical parameters change during different Kata Unsu jump techniques.Appropriate performance capacity indicators based on the neuromechanical evaluation can describe changes due to a modification of the technique.

Relative total body fat and skinfold patterning in filipino national combat sport athletes

The purpose of this study was to assess relative total body fat and skinfold patterning in Filipino national karate and pencak silat athletes. Participants were members of the Philippine men's and women's national teams in karate (12 males, 5 females) and pencak silat (17 males and 5 females). In addition to age, the following anthropometric measurements were taken: height, body mass, triceps, subscapular, supraspinale, umbilical, anterior thigh and medial calf skinfolds. Relative total body fat was expressed as sum of six skinfolds. Sum of skinfolds and each individual skinfold were also expressed relative to Phantom height. A two-way (Sport*Gender) ANOVA was used to determine the differences between men and women in total body fat and skinfold patterning. A Bonferroni-adjusted alpha was employed for all analyses. The women had a higher proportional sum of skinfols (80.19 ± 25.31 mm vs. 51.77 ± 21.13 mm, p = 0. 001, eta(2) = 0.275). The men had a lower proportional triceps skinfolds (-1.72 ± 0.71 versus - 0.35 ± 0.75, p < 0.001). Collapsed over gender, the karate athletes (-2.18 ± 0.66) had a lower proportional anterior thigh skinfold than their pencak silat colleagues (-1.71 ± 0.74, p = 0.001). Differences in competition requirements between sports may account for some of the disparity in anthropometric measurements. Key PointsThe purpose of the present investigation was to assess relative total body fat and skinfold patterning in Filipino national karate and pencak silat athletes.The results seem to suggest that there was no difference between combat sports in fatness.Skinfold patterning was more in line with what was reported in the literature with the males recording lower extremity fat.