Training using virtual reality improves response behavior in karate kumite

Assessment of the intensity and attractiveness of physical exercise while playing table tennis in an immersive virtual environment depending on the game mode

BACKGROUND

It appears that active video games (AVGs) and training apps that allow for physical activity (PA) in immersive virtual reality (VR) may be useful for sports, health-enhancing PA, and physical education (PE). Therefore, research is needed to identify their potential.

OBJECTIVE

The study aimed to evaluate the intensity and attractiveness of exercise during table tennis (TT) training in VR in arcade and simulation modes and to assess the potential for using such exercises in health-enhancing PA, sport, and PE.

METHODS

The research used the Racket Fury: Table Tennis VR. Exercise intensity during TT training in VR was evaluated by heart rate (HR) monitoring and rating of perceived exertion (RPE 6-20). The effectiveness of short-term TT training in VR was estimated based on the user's performance in playing against an opponent with artificial intelligence (AI), satisfaction with playing TT was measured using the Physical Activity Enjoyment Scale (PACES), and the potential usefulness of the tested app in PA, sport, and PE was assessed based on a questionnaire for participating PE teachers (30 participants).

RESULTS

PA intensity during TT training in VR expressed as a percentage of maximum heart rate (HRmax) was moderate but was significantly (p < 0.001; d=-0.830) higher in the easier arcade mode (69.50 ± 12.58%HRmax) than in the simulation mode (64.10 ± 9.67%HRmax). Despite the greater fatigue of respondents, user satisfaction was significantly higher in arcade mode. Users' performance when playing with AI was significantly better after 20 min of training in VR than before training. PE teachers recognize the great potential of the app.

CONCLUSIONS

The application tested is characterized by a beneficial PA intensity, with its level depending on the game mode. Facilitating strokes during a game of virtual TT promotes increased intensity of exercise and increased enjoyment of the PA. Short-term TT training in VR improves playing skills in a virtual environment. PE teachers spoke highly of the app and recognized the potential for using VR technology in PA, sports, and school PE.

Effect of Elastic Resistance on Exercise Intensity and User Satisfaction While Playing the Active Video Game BoxVR in Immersive Virtual Reality: Empirical Study

Background

One of the main contemporary forms of physical activity (PA) involves exercises and games in an immersive virtual reality (VR) environment, which allows the user to practice various forms of PA in a small space. Unfortunately, most of the currently available VR games and workout applications are mostly based on upper body movements, especially the arms, which do not guarantee sufficiently high exercise intensity and health benefits. Therefore, it is worth seeking solutions to help increase the exercise load during PA in VR.

Objective

The main aim of this study was to evaluate the effect of elastic arm resistance in the form of latex resistance bands of different elasticity levels on the intensity of students' PA while playing the BoxVR game. We further assessed the satisfaction of this form of exercise and its associations with PA intensity.

Methods

A total of 21 healthy and physically fit men (mean age 22.5, SD 2.0 years) were included in the study. The tests consisted of 3 10-minute games. One game was run with no load and the other two were run with 1.5-meter latex resistance bands (low and high resistance). The order of the tests was randomized and the participants rested for 20 minutes after each exercise. Exercise intensity was estimated using objective (heart rate monitoring) and subjective (Borg scale) methods. The Physical Activity Enjoyment Scale was used to assess satisfaction with the PA. The effect of elastic resistance on exercise intensity and user enjoyment was estimated using ANOVA for repeated measures.

Results

The ANOVA results indicated that incorporation of elastic resistance caused a significant change (F2,40=20.235, P<.001; η²p=0.503) in the intensity of PA in VR, which was low while playing without resistance and then increased to a moderate level with additional resistance. The use of elastic bands also changed participants' perceptions of the enjoyment of exercise in VR (F2,40=9.259, P<.001; η²p=0.316). The students rated their satisfaction with PA in VR on a 7-point scale highly and similarly when exercising without an upper limb load (mean 6.19, SD 0.61) and with slight elastic resistance (mean 6.17, SD 0.66), whereas their satisfaction declined significantly (mean 5.66, SD 0.94) when incorporating a higher load.

Conclusions

The intensity of PA among students playing the BoxVR game is at a relatively low level. With the added resistance of elastic bands attached to the upper limbs, the intensity of the exercise increased to a moderate level, as recommended for obtaining health benefits. Participants rated the enjoyment of PA in VR highly. The use of slight elastic resistance did not negatively affect satisfaction with the BoxVR game, although user satisfaction declined with a higher load. Further research should be undertaken to increase the effectiveness of exercise in VR so that regular users can enjoy the health benefits.

Application of immersive virtual reality in the training of wheelchair boxers: evaluation of exercise intensity and users experience additional load- a pilot exploratory study

BACKGROUND

Over the last few years, there has been a growing interest in workout apps and active virtual reality video games (AVRGs), which provide entertainment and enable users to undertake various forms of physical activity (PA) at home. Presumably, these types of exercises can be particularly useful for people with physical disabilities, who experience problems with access to sports and leisure facilities due to architectural and communication barriers. However, it is interesting whether the intensity of PA in VR is high enough to provide users with health benefits, as it is mainly based on arm movements.

OBJECTIVE

The main aim of the study was to evaluate the intensity of physical exercise of wheelchair boxers during a boxing training session using the FitXR app in immersive VR in light of health-related PA recommendations. The effect of Velcro-fastened hand-held weights (HHWs) on the intensity of PA undertaken by people in VR was also examined, and the attractiveness of virtual exercise were assessed in the opinion of users.

METHODS

PA intensity was evaluated using a heart rate monitor based on the percentage of maximal heart rate (% HRmax) and the Borg's rating of perceived exertion (RPE 6-20). The attractiveness perceived during exercise by users were evaluated using the Physical Activity Enjoyment Scale (PACES 1-7 scale).

RESULTS

The study shows that the exercise intensity of the athletes during wheelchair boxing training in VR is at a beneficial moderate level for health (HRave=68.98% HRmax). The use of HHWs (0.5 kg) does not significantly increase the PA intensity of the individuals during virtual exercise. Users with disabilities highly rated the attractiveness (6.32 ± 0.79 points) of PA during virtual boxing training.

CONCLUSIONS

Boxing exercises in VR can be an attractive and health-related form of PA for wheelchair boxers and a supplement to their conventional training.

Virtual training, real effects: a narrative review on sports performance enhancement through interventions in virtual reality

The present article reports a narrative review of intervention (i.e., training) studies using Virtual Reality (VR) in sports contexts. It provides a qualitative overview and narrative summary of such studies to clarify the potential benefits of VR technology for sports performance enhancement, to extract the main characteristics of the existing studies, and to inform and guide future research. Our literature search and review eventually resulted in 12 intervention studies with a pre vs. post design focused on different sports, including target and precision sports (archery, bowling, curling, darts, golf), bat/racquet and ball sports (baseball, table tennis), goal sports (football/soccer, basketball), martial arts (karate), and sport-unspecific processes such as bodily sensations and balancing. The samples investigated in the primary studies included novice, amateur, and expert athletes (total aggregated sample size N = 493). Many studies found statistically significant effects in relevant target skills following interventions in VR, often outperforming training effects in passive or active control conditions (e.g., using conventional training protocols). Therefore, interventions in VR (or extended reality) have the potential to elicit real effects in sports performance enhancement through training of motor and psychological skills and capabilities in athletes, including perception-action skills, strategic, tactical and decision-making, responding to unexpected events, and enhancing psychological resilience and mental performance under pressure. The neurocognitive mechanisms (e.g., visual search behavior, imagery), methodological aspects (e.g., adaptive training difficulty), and the issues of real-world transfer and generalizability via which these potential sports-performance-related improvements may occur are discussed. Finally, limitations of the present review, the included studies, the current state of the field in general as well as an outlook and future perspectives for research designs and directions are taken into consideration.

Adaptive enhancement design of non-significant regions of a Wushu action 3D image based on the symmetric difference algorithm

The recognition of martial arts movements with the aid of computers has become crucial because of the vigorous promotion of martial arts education in schools in China to support the national essence and the inclusion of martial arts as a physical education test item in the secondary school examination in Shanghai. In this paper, the fundamentals of background difference algorithms are examined and a systematic analysis of the benefits and drawbacks of various background difference algorithms is presented. Background difference algorithm solutions are proposed for a number of common, challenging problems. The empty background is then automatically extracted using a symmetric disparity approach that is proposed for the initialization of background disparity in three-dimensional (3D) photos of martial arts action. It is possible to swiftly remove and manipulate the background, even in intricate martial arts action recognition scenarios. According to the experimental findings, the algorithm's optimized model significantly enhances the foreground segmentation effect of the backdrop disparity in 3D photos of martial arts action. The use of features such as texture probability is coupled to considerably enhance the shadow elimination effect for the shadow problem of background differences.

Assessment of a karate performer's position estimation system without any markers

Karate has become more popular, and researches have been conducted on training methods and motion analysis related to karate. The AR system for karate is an effective system for training and for the audience to understand the performance. To develop the AR system, it is necessary to acquire the movement of the performer. The purpose of the research is to assess a motion capture system to estimate a karate performer's full-body position and posture from HoloLens 2, without wearing any attachments. We used ThreeDPoseUnityBarracuda to estimate the position and posture of the performer's joints. In the experiment, the estimated joint's positions were compared with actual positions using the inertial three-dimensional motion capture. As results, although the error increased when the performer's movement was large, the median error between the estimated and actual positions was a maximum of 0.24 m at the x-coordinate of the right hand, and high accuracy was obtained when the performer's movement was small.

Gymnastic skills on a balance beam with simulated height

Virtual reality (VR) is a valuable tool for simulating dangerous situations and training under these conditions with a reduced possibility of injury. This could be beneficial within different sports scenarios. In gymnastics, the height of the balance beam can be dangerous and frightening, especially for beginners. Here, a simulated height can reduce the participant's risk of injury and facilitate entry to balance beam gymnastics. However, the investigation of sports performance in a virtual environment is rare. Therefore, the current study aims to compare beginners' performance in balance beam tasks between the real world (RW) and VR. 34 sports students executed gymnastic balancing forward, backward and the extension of one leg to the front, the side and the back on a regular balance beam in the RW and on a balance beam with simulated height in VR (using a head-mounted display). We analyzed beginners' performance in both conditions (RW and VR) regarding different criteria for each balance beam task. Statistical analyses show significant differences in performance with better results in RW (p < .05). Especially the body tension and the upper body posture were superior in RW. One explanation can be the more difficult regulation of the balance in VR. For the tasks where the motion took part in a fixed position on the beam, the further performance aspects were similar for RW and VR. When the participants moved along the beam, further performance aspects, like the leg extension, were better in RW. In total, the participants executed the VR balance beam tasks with decreased danger of injury due to the simulated height of the balance beam, but their performance was slightly limited. We conclude that for the first contact with the height of a balance beam, VR is a suitable tool to reduce the danger of injury occurring from falling off the beam and facilitate entry to balance beam gymnastics.

Comparison of response behavior in karate kumite between real world and virtual reality

Virtual reality is increasingly applied to support physical training and improve athletes’ performance in sports. Nevertheless, there is a research deficit in that, especially in martial arts, it has not yet been shown to what extent the response behavior of athletes in virtual reality is the same as in the real world. If this can be confirmed, a transfer of VR-adapted skills to RW can be expected and sports training in a virtual environment can be applied to improve sports performance. Since the response behavior is essential for many sports, this study compares it in karate kumite to the competition-important attack (Kizami-Zuki) of a real and a virtual opponent. Experienced karate athletes wore a head-mounted display and were asked to respond quickly and efficiently to 22 karate attacks, of which eight were Kizami Zuki’s attacks. Using a video-based movement assessment, karate experts quantified the response behavior with the parameters ‘time for response’, ‘response quality’ and ‘kind of response’. Results show no significant differences in ‘time for response’ and ‘kind of response’ between both conditions (virtual reality vs. real world). Only the ‘response quality’ was rated better in real world than in virtual reality. It is concluded that the ‘time of response’ and ‘kind of response’ for karate kumite athletes in virtual reality are similar to that in the real world.

Global trends and hotspots in research on extended reality in sports: A bibliometric analysis from 2000 to 2021

Objective

Extended reality technologies (e.g. virtual reality (VR), augmented reality (AR) and mixed reality (MR)) are gaining popularity in sports owing to their unique advantages. This study aims to analyse the progress of the application of extended reality technology in sports and reveal its cooperative features, research hotspots and development trends.

Methods

We searched the literature in the Web of Science Core Collection (WoSCC) database within the period 2000 to 2021 and conducted a bibliometric analysis. The analysis methods included statistical, co-occurrence, hierarchical clustering and social network analyses.

Results

A total of 340 articles were gathered. The literature related to its research showed an increasing trend over time. The paper collaboration rate was 90.88% (309/340 papers), and the degree of author collaboration was 3.96 (1345/340). VR was found to be the most productive journal, and Queen's University Belfast was the most productive institution. The United States, China and the United Kingdom were the three main contributors to the field. The foundational themes in sports extended reality research were (i) sports games and extended reality systems, (ii) virtual simulation devices and artificial intelligence, (iii) sports training and performance and (iv) age-appropriate physical activity, sports rehabilitation and physical education.

Conclusion

The level of author collaboration was low, but the degree of author collaboration is largely on the rise. The closeness of the collaboration between institutions and countries was also low. In addition, the subject of sport extended reality is relatively fragmented. Therefore, more research is needed to strengthen it in the future.

Influence of body visualization in VR during the execution of motoric tasks in different age groups

Virtual reality (VR) has become a common tool and is often considered for sport-specific purposes. Despite the increased usage, the transfer of VR-adapted skills into the real-world (RW) has not yet been sufficiently studied, and it is still unknown how much of the own body must be visible to complete motoric tasks within VR. In addition, it should be clarified whether older adults also need to perceive their body within VR scenarios to the same extent as younger people extending the usability. Therefore, younger (18-30 years old) and elderly adults (55 years and older) were tested (n = 42) performing a balance-, grasping- and throwing task in VR (HMD based) accompanied with different body visualization types in VR and in the RW having the regular visual input of body's components. Comparing the performances between the age groups, the time for completion, the number of steps (balance task), the subjective estimation of difficulty, the number of errors, and a rating system revealing movements' quality were considered as examined parameters. A one-way ANOVA/Friedmann with repeated measurements with factor [body visualization] was conducted to test the influence of varying body visualizations during task completion. Comparisons between the conditions [RW, VR] were performed using the t-Tests/Wilcoxon tests, and to compare both age groups [young, old], t-Tests for independent samples/Mann-Whitney-U-Test were used. The analyses of the effect of body visualization on performances showed a significant loss in movement's quality when no body part was visualized (p < .05). This did not occur for the elderly adults, for which no influence of the body visualization on their performance could be proven. Comparing both age groups, the elderly adults performed significantly worse than the young age group in both conditions (p < .05). In VR, both groups showed longer times for completion, a higher rating of tasks' difficulty in the balance and throwing task, and less performance quality in the grasping task. Overall, the results suggest using VR for the elderly with caution to the task demands, and the visualization of the body seemed less crucial for generating task completion. In summary, the actual task demands in VR could be successfully performed by elderly adults, even once one has to reckon with losses within movement's quality. Although more different movements should be tested, basic elements are also realizable for elderly adults expanding possible areas of VR applications.

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.

Effects of body visualization on performance in head-mounted display virtual reality

Although there are many virtual reality (VR) applications in sports, only a handful of studies visualized the whole body. There is still a lack of understanding, how much of the own body must be visualized in the head-mounted display (HMD) based VR, to ensure fidelity and similar performance outcome as in the real-world. In the current study, 20 young and healthy participants completed three tasks in a real and virtual environment: balance task, grasping task, and throwing task with a ball. The aim was to find out the meaning of the visualization of different body parts for the quality of movement execution and to derive future guidelines for virtual body presentation. In addition, a comparison of human performance between reality and VR, with whole-body visualization was made. Focusing on the main goal of the current study, there were differences within the measured parameters due to the visualization of different body parts. In the balance task, the differences within the VR body visualization consisted mainly through no-body visualization (NB) compared to the other visualization types defined as whole-body (WB), WB except feet (NF), as well as WB except feet and legs (NLF). In the grasping task, the different body visualization seemed to have no impact on the participants' performances. In the throwing task, the whole-body visualization led to higher accuracy compared to the other visualization types. Regarding the comparison between the conditions, we found significant differences between reality and VR, which had a large effect on the parameters time for completion in the balance and grasping task, the number of foot strikes on the beam in the balance task, as well as the subjective estimation of the difficulty for all tasks. However, the number of errors and the quality of the performances did not differ significantly. The current study was the first study comparing sports-related tasks in VR and reality with further manipulations (occlusions of body parts) of the virtual body. For studies analyzing perception and sports performance or for VR sports interventions, we recommend the visualization of the whole body in real-time.

Transfer of motor skill between virtual reality viewed using a head-mounted display and conventional screen environments

BACKGROUND

Virtual reality viewed using a head-mounted display (HMD-VR) has the potential to be a useful tool for motor learning and rehabilitation. However, when developing tools for these purposes, it is important to design applications that will effectively transfer to the real world. Therefore, it is essential to understand whether motor skills transfer between HMD-VR and conventional screen-based environments and what factors predict transfer.

METHODS

We randomized 70 healthy participants into two groups. Both groups trained on a well-established measure of motor skill acquisition, the Sequential Visual Isometric Pinch Task (SVIPT), either in HMD-VR or in a conventional environment (i.e., computer screen). We then tested whether the motor skills transferred from HMD-VR to the computer screen, and vice versa. After the completion of the experiment, participants responded to questions relating to their presence in their respective training environment, age, gender, video game use, and previous HMD-VR experience. Using multivariate and univariate linear regression, we then examined whether any personal factors from the questionnaires predicted individual differences in motor skill transfer between environments.

RESULTS

Our results suggest that motor skill acquisition of this task occurs at the same rate in both HMD-VR and conventional screen environments. However, the motor skills acquired in HMD-VR did not transfer to the screen environment. While this decrease in motor skill performance when moving to the screen environment was not significantly predicted by self-reported factors, there were trends for correlations with presence and previous HMD-VR experience. Conversely, motor skills acquired in a conventional screen environment not only transferred but improved in HMD-VR, and this increase in motor skill performance could be predicted by self-reported factors of presence, gender, age and video game use.

CONCLUSIONS

These findings suggest that personal factors may predict who is likely to have better transfer of motor skill to and from HMD-VR. Future work should examine whether these and other predictors (i.e., additional personal factors such as immersive tendencies and task-specific factors such as fidelity or feedback) also apply to motor skill transfer from HMD-VR to more dynamic physical environments.

Comparison of response quality and attack recognition in karate kumite between reality and virtual reality – a pilot study

Virtual reality (VR) is an often-used instrument in sports science research and practical training. However, VR studies with experienced athletes and sports specific tasks are rare. Furthermore, the transfer from interventions in VR into reality is even less investigated. It is possible to analyze benefits of VR using in-situ studies comparing human behavior in VR with reality. If no differences occur in the human behavior, then VR would be appropriate for interventions to improve athletes’ performance. Therefore, we let seven karate athletes respond each to ten attacks of a real attacker (reality) and a virtual attacker (VR using a Head Mounted Display) and compared the parameters “response quality” and “attack recognition” under both conditions. As attacks we chose Gyaku-Zuki (reverse punch, GZ) and Kizami-Zuki (attack with the front arm, KZ). ANOVAs and sign tests showed isolated cases of significant differences between both conditions: response quality in KZ, and attack recognition for 150ms in GZ, all p0.05). The remaining comparisons showed no significant differences (p>0.05). We conclude that further research is needed but the results of the present pilot study are promising to assume that VR is suitable for applications because similar performance outcome in reality and VR were obtained.