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.

Influence of Target Width and Distance on Postural Adjustments in a Fencing Lunge.

The aim of this study was to examine whether target width and target distance influence the planning phase of a fencing lunge (early and anticipatory postural adjustments) as well as the execution phase of a fencing lunge. Eight elite female fencers participated in the study. The displacement of the center of foot pressure, muscle activity of the tibialis anterior, and kinematics of center of mass were recorded using force plates. The results show that target width and distance have no effect on early and anticipatory postural adjustments as well as the acceleration and velocity of the center of mass at the moment of foot-off. However, a greater target distance was associated with a greater max center of mass acceleration and velocity, and larger target width resulted in a greater max center of mass acceleration during lunging (p < 0.05). We suppose that the effect of task parameters on preparing a fencing lunge may be mitigated due to the specific technique adopted by expert fencers and the ballistic nature of a fencing lunge.

Presence of an Overhead Goal Does Not Improve the Effectiveness of Jump Training.

ABSTRACT: Akbas, A, Marszalek, W, and Król, H. Presence of an overhead goal does not improve the effectiveness of jump training. J Strength Cond Res 37(4): e280-e288, 2023-This study investigated the effectiveness of jump training with and without an overhead goal (OG) on a modified countermovement jump (CMJ) tested in a similar manner, with and without OG. Fifty-two men divided into 3 groups-trained with OG, trained without OG, and untrained-were examined: before the commencement of training; after 2, 4, and 6 weeks of training; and 2 weeks after the discontinuation of training. Each session consisted of 50 modified CMJ and was performed 3 times per week. Countermovement jump height, mean power, peak power, countermovement depth, and take-off phase time were quantified, and the statistical level was set at p < 0.05. Although the results showed the beneficial effect of OG on jump height ( p < 0.01), the training with OG did not bring significantly better results than training without OG. In addition, the group trained without OG improved after 2 weeks in both testing conditions (with and without OG), whereas the group trained with OG improved after 2 weeks when tested with OG and only after 6 weeks when tested without OG. We believe the use of OG in jump training may be detrimental when the OG is withdrawn from the testing procedure because of its strong motivational and feedback features. Consequently, athletes in disciplines which require them to jump toward an object located over their head during a game, e.g., a ball or crossbar, should be tested with the presence of OG. Despite this, OG is still an important factor in maximizing jump performance.

The effect of expertise on postural control in elite sport ju-jitsu athletes.

BACKGROUND: Due to the high postural control demands of sport ju-jitsu, it is likely that long-term sport ju-jitsu training may induce sport-specific adaptations in postural control, especially in positions directly related to combat. The aim of the study was to assess the differences in postural control between elite sport ju-jitsu athletes and untrained controls in non-ecological and ecological conditions and to investigate the relative contribution of spinal and supraspinal mechanisms to postural control in expert athletes. METHODS: The study was conducted on eleven male elite ju-jitsu athletes and ten non-athletes. The data was collected with the use of a force plate under two conditions: quiet standing and ju-jitsu combat stance. Apart from the standard analysis of the spatial-temporal parameters of center of foot pressure, non-linear measures were used, namely rambling-trembling and sample entropy. The non-parametric Mann-Whitney U test was used to compare both groups. RESULTS: The main findings of the study showed that in quiet standing, elite ju-jitsu athletes and non-athletes had comparable postural control in both the anterior-posterior and mediolateral planes. In contrast, in the combat stance, elite athletes had lower values of postural sway and rambling component (range and rms) and higher values of sample entropy in comparison to the non-athletes (p < 0.05). No differences were found in the trembling component of sway between groups in the combat stance (p < 0.05). CONCLUSIONS: Smaller postural sway and its rambling component in sport ju-jitsu athletes may indicate the more precise control of center of foot pressure and improved ability in estimating its position. The sample entropy results confirmed that the displacement of center of foot pressure for sport ju-jitsu athletes was more irregular, which demonstrates greater automatization in postural control. The results also confirm the importance of ecological validity in investigating postural adaptations associated with sports expertise.

The effect of a light finger touch on the signal complexity during quiet standing.

The purpose of the study was to investigate the influence of additional tactile information (light fingertip touch) on the postural sway and regularity of center-of-pressure (COP) fluctuations. Thirty-two young, healthy participants performed a quiet standing task (30 s) on a force platform with and without light fingertip touch. COP time-series were analyzed using standard postural sway measures (range, root mean square error, velocity), COP regularity was measured with Sample entropy. Participants demonstrated significantly smaller postural sway with a light touch, but only in the anteroposterior direction. The amount of sway with additional tactile information in the sagittal plane reached the level of sway in the frontal plane without this information. Similarly, COP fluctuations were more irregular during light touch condition only in the anteroposterior direction, as evidenced by significantly higher Sample entropy. Furthermore, COP regularity decreased in the sagittal plane and reached level in the frontal plane without light touch. These results suggest that postural sway is mostly controlled in the sagittal plane and that in the mediolateral direction the control is mostly automated. In conclusion, our results support the notion that the light touch provides additional information which enhances postural stabilization. Our results expand the relation between COP regularity and the attention invested in posture in the touch domain and prove that light touch, as an attentional demanding task, leads to increased COP irregularity. Nonlinear measures of signal regularity (i.e., SampEn) provide surplus insight into human postural control and can be used as an additional useful tool to traditional balance measures.

Influence of base of support on early postural adjustments and fencing lunge performance.

The aim of the study was to examine whether the width of the base of support (BOS) has an influence on early postural adjustments (EPA) and armed upper limb and COM kinematics during lunging. Eight elite female fencers participated in the study. The displacement of the centre of foot pressure (COP) and kinematics of centre of mass (COM) were recorded using force platforms. The kinematics of the wrist of the armed upper limb were obtained using a 3D accelerometer. The results show that EPA were characterised by a very small COP displacement (about 0.6 to 1.2 cm). The COP amplitude showed a tendency to decrease with an increase in BOS width under reaction time conditions. In contrast, a greater BOS width was associated with a significant increase in COM acceleration at foot-off and peak COM acceleration during lunging also under reaction time instructions. The kinematics of the wrist were not influenced by BOS. The results show that in elite fencers, the upper limb movement is dissociated from the whole body movement. We suppose that a small COP amplitude is a postural skill which is integrated into the lunging skill and might influence the acceleration of COM.

Two Aspects of Feedforward Control During a Fencing Lunge: Early and Anticipatory Postural Adjustments.

The present study investigated whether expertise in fencing influences the onset of postural preparation during the fencing lunge and how it changes under different performance conditions. We also questioned if the onset of feedforward control can be categorized into one of the postural phases: anticipatory or early postural adjustment. Eight elite fencers and nine physical education students performed an attack with a lunge in self-paced and reaction time conditions from three different initial stance widths. The onset of the center of pressure (COP) displacement and EMG activities for the tibialis anterior (TA) of both limbs were recorded. The results show that expertise in fencing delays the onset of the activity of TA of the front leg and the onset of COP displacement during fencing lunge performance in comparison to controls. Additionally, in contrast to the control group, fencers produce typical APA patterns in the activation of TA under different performance conditions, delayed reaction time in comparison to self-initiated lunging, and constant time of APA onset under different widths of stance. According to different times and functions of TA activity and COP displacement in lunging, we propose to address them as anticipatory postural adjustment and early postural adjustment, respectively.

The Effects of Exergaming Training on Balance in Healthy Elderly Women-A Pilot Study.

Our aim was to observe, through objective testing using an assessment module incorporated in a new exergaming system, whether elderly people's static and functional balance is improved by a balance exergaming training program based on movements performed in everyday life. Thirteen healthy elderly women participated in 12 sessions of balance-based exergaming training (three times a week, 30 min per session). All objective outcomes, the quiet standing test, functional balance test (FBT), and limit of stability (LOS) test, were measured on three occasions: before intervention, after six training sessions, and after the completion of the four-week program. The results showed a significant improvement in LOS performance after the intervention. In FBT, participants exhibited a significant decrease (p < 0.01; Kendall's W = 0.5) in the average time to target hit after six trainings. The average center of pressure velocity increased after six and 12 sessions, however did not reach significance (p = 0.053); nevertheless the size of the effect was large (ηp2 = 0.22). The parameters of the quiet standing test were not significantly affected by the training. The results support the need for more definite and objective studies assessing exergaming for balance in elderly.

Transitional Locomotor Tasks in People With Mild to Moderate Parkinson's Disease.

Background: People with Parkinson's disease (PD) exhibit deficits in maintaining balance both during quiet standing and during walking, turning, standing up from sitting, and step initiation. Objective: The purpose of this study was to examine balance disorders during a transitional task under different conditions in participants with PD. Methods: The research was conducted on 15 PD-II (mild) and 15 PD-III (moderate) individuals (H&Y II-III stage) and 30 healthy elderly. The transitional task was measured on two force platforms (A and B). The procedure consisted of three phases: (1) quiet standing on platform A, (2) crossing to platform B, and (3) quiet standing on platform B, each until measurements were completed. There were four conditions: crossing without an obstacle, crossing with an obstacle, and walking up and down the step. Results: There were no significant differences between mild PD individuals and healthy elderly during quiet standing before the transitional task and after completing the task. The temporal aspects describing the different transitional tasks were comparable between mild PD and healthy subjects. Moderate PD participants presented a significantly higher COP velocity after the transitional task compared to the healthy older adults (p < 0.05). Additionally, the moderate PD group showed significantly higher values for transit time relative to healthy subjects during the transitional task in all conditions (p < 0.05). Conclusions: Disease severity affects the temporal aspects of different transitional tasks in people with PD. The procedure of completing a transitional task under different conditions allowed differences between moderate and mild PD stages and healthy subjects to be observed.

Application of Virtual Reality in Competitive Athletes - A Review.

The purpose of this study was to determine the state of the art in the area of virtual reality in competitive athletes of different levels of expertise in various disciplines and point the areas of its application. Articles published before August 2018 were considered in our review. The PubMed, SCOPUS, SportDiscus and Medline databases were searched. A combination of the following search terms was used: virtual reality, virtual environment, virtual system, athletes, sports, physical training, sport performance, physical exercises. Studies involved healthy competitive athletes. A total of 18 articles met the inclusion criteria. There were three areas of application of virtual reality to sport: performance analysis, simulation improvement and virtual training. Competitive athletes were mostly examined in a semi-immersive setting. In conclusion, virtual reality seems to play a marginal role in competitive athletes' training. Due to the fact that virtual reality interventions bring significant improvements in clinical research, well-designed randomized control trials with detailed virtual training programmes are required in the future. Practically, virtual reality is effectively and commonly used to analyse performance in competitive athletes. There is still a need of creating fully interactive VR, where athletes will be able to cooperate with a virtual partner and influence the environment.