The phenomenon of anticipation in fencing. An applicability approach.

Introduction: The aim of the study was to determine the structure of muscular activity and ground reaction forces during the preparatory period and the execution of a fencing lunge at the opponent's torso. The analysis focused on the correlations between three phases of a fencing technical action in the context of factors of temporal anticipation. Methods: Six female épée fencers from the Polish National Fencing Team participated in the study. The research tools included electromyography (EMG), ground reaction force (GRF) platforms, and the OptiTrack motion capture system. The fencers performed the lunge three times in response to visual cues from the coach. By integrating the testing system, the EMG signal indices of the fencers' upper and lower limbs and the vertical force values of the fencers' front and rear leg muscles were obtained simultaneously. Results: The results of the study demonstrated the key role of five muscles: BICEPS BRACHII, LAT TRICEPS, EXTCARP RAD, BICEPS FEMORIS and MED GAS in influencing the speed of lunge execution. In addition, a significant correlation was found between the EMG signal of the gastrocnemius muscle of the rear leg and the movement time (MT) phase of the lunge execution. Discussion: The anticipatory activation of the EMG signal in relation to the vertical force waveforms generated by the ground forces response platform in the 15-30 ms interval was demonstrated. Finally, the importance of the preparatory period for the effectiveness of the fencing lunge was highlighted based on the phenomenon of anticipation.

Initial study on an expert system for spine diseases screening using inertial measurement unit.

In recent times, widely understood spine diseases have advanced to one of the most urgetn problems where quick diagnosis and treatment are needed. To diagnose its specifics (e.g. to decide whether this is a scoliosis or sagittal imbalance) and assess its extend, various kind of imaging diagnostic methods (such as X-Ray, CT, MRI scan or ST) are used. However, despite their common use, some may be regarded as (to a level) invasive methods and there are cases where there are contraindications to using them. Besides, which is even more of a problem, these are very expensive methods and whilst their use for pure diagnostic purposes is absolutely valid, then due to their cost, they cannot rather be considered as tools which would be equally valid for bad posture screening programs purposes. This paper provides an initial evaluation of the alternative approach to the spine diseases diagnostic/screening using inertial measurement unit and we propose policy-based computing as the core for the inference systems. Although the methodology presented herein is potentially applicable to a variety of spine diseases, in the nearest future we will focus specifically on sagittal imbalance detection.

Quantitative Assessment of Upper Limb Movement in Post-Stroke Adults for Identification of Sensitive Measures in Reaching and Lifting Activities.

BACKGROUND: The assumption of this work is the achievement of objective results of the movement structure, which forms the basis for in-depth analysis and, consequently, for determining the upper limb movements that are most affected by stroke compared to healthy people. METHODS: An analysis of relevant and systematically identified features of upper limb movement in post-stroke adults is presented based on scalable hypothesis tests. The basic features were calculated using movements defined by the x, y, and z coordinates (i.e., 3D trajectory time series) and compared to the results of post-stroke patients with healthy controls of similar age. RESULTS: After automatic feature selection, out of the 1004 common features of upper limb movement, the most differentiated were the upper arm movements in reaching kinematics. In terms of movement type, movements in the frontal plane (shoulder abduction and adduction) were the most sensitive to changes. The largest number of discriminating features was determined on the basis of acceleration time series. CONCLUSIONS: In the 3D assessment of functional activities of the upper limb, the upper arm turned out to be the most differentiated body segment, especially during abduction and adduction movements. The results indicate a special need to pay attention to abduction and adduction movements to improve the activities of daily living of the upper limbs after a stroke.

Influence of school backpack load on plantar foot pressure during walking in 9-11 years old girls.

OBJECTIVE: This study aimed to assess the relative load of the midfoot and the metatarsals of both feet when schoolchildren walked with backpacks of different loads. METHODS: A group of 12 healthy girls (9.9 ± 0.8 years; 33.8 ± 6.7 kg, 1.40 ± 0.10 m) walked barefoot to assess plantar pressures during gait without load (L0%) and with a loaded backpack equal to 10% (L10%) and 20% (L20%) of their body weight. A Footscan® system (RSscan International, Belgium) was used to determine the contact area and relative pressure impulse in the midfoot and metatarsals on the dominant (DL) and non-dominant legs (NL). RESULTS: The effect of load was significant for the contact area of the midfoot for both NL (p = 0.013) and DL (p = 0.001). In the metatarsals, there was significantly greater relative impulse during L10% compared to L0% in the first (p = 0.041) and second (p = 0.050) metatarsals of the DL. Comparing the NL and DL showed significantly greater relative impulse on the DL in the fourth metatarsal during L10% (p = 0.023), greater contact area in the fifth metatarsal during L0% (p = 0.050), and greater impulse in the midfoot during L20% (p = 0.028) on the NL. CONCLUSIONS: The school backpack load influences relative plantar pressure distribution, especially in the midfoot. Further, our findings suggest greater propulsion of the DL and supporting function of the NL.

Movement Patterns of Polish National Paralympic Team Wheelchair Fencers with Regard To Muscle Activity and Co-Activation Time.

The aim of this study was to determine muscle co-activation and muscle activity time using EMG in Paralympic wheelchair fencers categorized into two disability-level groups: A (n= 7) and B (n= 9). The study was carried out with the use of a 16-channel EMG system. The surface EMG electrodes were placed on the fencer's body along nine channels: arm muscles - deltoideus middle head (DEL), triceps brachii (TRI) and biceps brachii (BC); forearm muscles - extensor carpi radialis longus (ECR), flexor carpi radialis (FCR); postural (abdominal and back) muscles - the right and the left external oblique abdominal (EOA RT and LT) and latissimus dorsi (LD RT and LT). To assess the relative level of co-activation (simultaneous contraction of both muscles) for the TRI-BC, ECR-FCR, LD RT-EDA RT and LD LT-EDA LT muscle pairs, the co-activation index (CI) was calculated. The collected data were processed using Jamovi. The study hypotheses were verified at the level of significance of p≤0.05 (Welch's t-test). The normal distribution of analyzed statistical features was checked with the Shapiro-Wilk test. The analysis of muscle activation time, as a percent ratio of three attempts executed in a series, confirmed the study assumptions. Fencers from Group A had a shorter activation time in all tested muscles, with the exception of the ECR (58.24), than fencers from Group B. This confirms that the activation of antagonist muscles representing a centrally programmed anticipatory mechanism stabilizing technical actions was particularly intensified in Group A fencers. The study results indicate that the standard co-activation index (CI) of key muscles involved in wheelchair fencing ranges from 48 to 51%.

Correlations between the EMG Structure of Movement Patterns and Activity of Postural Muscles in Able-Bodied and Wheelchair Fencers.

The study involved Paralympic wheelchair fencers (N = 7) in two disability categories, and able-bodied female epee fencers (N = 7), members of the polish paralympic fencing teams. The performance of postural muscles and sword arm muscles in both groups of fencers, and of the front and rear leg muscles in the able-bodied fencers, was examined using surface electromyography with an accelerometer and the OptiTrack motion analysis system, as well as ground force reaction platforms. The activation sequence of individual muscles was determined and the structure of movement patterns in able-bodied and wheelchair fencers was formulated. A statistically significant correlation was found between the complex motor reaction time and latissimus dorsi muscle activation (p = 0.039, Z = -2.062) in wheelchair fencers. High correlations between the vertical force and EMG signal values of the gastrocnemius caput laterale muscle (0.85 for p = 0.022) were found in able-bodied fencers. A heuristic analysis indicated the significance of postural muscles in the movement patterns of wheelchair and able-bodied fencers. These muscles play a crucial role in the anticipatory postural adjustment of the trunk during technical fencing actions, including attacks on the opponent's body.

Assessment of Quality of Life and Pain Severity in Older Men with Osteoporosis: Cross-Sectional Study.

BACKGROUND: The quality of life in osteoporosis is studied for men rather than for women. Aim of the study was to determine how bone mass density (BMD) relates to life quality components and the severity of pain felt by men affected by osteoporosis. METHODS: Presented research is a cross-sectional study. The cohort of 62 men aged 65 to 85 years was divided into a group with osteoporosis (N = 27) and a group without osteoporosis (N = 35). The participants' quality of life was measured with the Qualeffo41 Questionnaire, BMD was quantified by densitometry, and pain intensity was assessed on the Visual Analogue Scale. RESULTS: We found that lower BMD was strongly correlated to participants' quality of life (r = -0.72), especially the quality of leisure and social activities (r = -0.66), general health perception (r = -0.59), and mobility (r = -0.57). Pain significantly affected general health perception in older men with osteoporosis. General health assessment and pain were highly correlated with each other (r = 0.888). CONCLUSION: BMD and the overall quality of life of the study participants were related to each other. The strongest relationship occurred between reduced BMD and leisure and social activities component. The pain significantly affected participants' general health perception. The results may be employed to create new prophylactic strategies to improve life quality in men with osteoporosis.

Wavelet coherence as a measure of trunk stabilizer muscle activation in wheelchair fencers.

BACKGROUND: Intermuscular synchronization constitutes one of the key aspects of effective sport performance and activities of daily living. The aim of the study was to assess the synchronization of trunk stabilizer muscles in wheelchair fencers with the use of wavelet analysis. METHODS: Intermuscular synchronization and antagonistic EMG-EMG coherence were evaluated in the pairs of the right and the left latissimus dorsi/external oblique abdominal (LD/EOA) muscles. The study group consisted of 16 wheelchair fencers, members of the Polish Paralympic Team, divided into two categories of disability (A and B). Data analysis was carried out in three stages: (1) muscle activation recording using sEMG; (2) wavelet coherence analysis; and (3) coherence density analysis. RESULTS: In the Paralympic wheelchair fencers, regardless of their disability category, the muscles were activated at low frequency levels: 8-20 Hz for category A fencers, and 5-15 Hz for category B fencers. CONCLUSIONS: The results demonstrated a clear activity of the trunk muscles in the wheelchair fencers, including those with spinal cord injury, which can be explained as an outcome of their intense training. EMG signal processing application have great potential for performance improvement and diagnosis of wheelchair athletes.

Optical motion capture dataset of selected techniques in beginner and advanced Kyokushin karate athletes.

Human motion capture is commonly used in various fields, including sport, to analyze, understand, and synthesize kinematic and kinetic data. Specialized computer vision and marker-based optical motion capture techniques constitute the gold-standard for accurate and robust human motion capture. The dataset presented consists of recordings of 37 Kyokushin karate athletes of different ages (children, young people, and adults) and skill levels (from 4th dan to 9th kyu) executing the following techniques: reverse lunge punch (Gyaku-Zuki), front kick (Mae-Geri), roundhouse kick (Mawashi-Geri), and spinning back kick (Ushiro-Mawashi-Geri). Each technique was performed approximately three times per recording (i.e., to create a single data file), and under three conditions where participants kicked or punched (i) in the air, (ii) a training shield, or (iii) an opponent. Each participant undertook a minimum of two trials per condition. The data presented was captured using a Vicon optical motion capture system with Plug-In Gait software. Three dimensional trajectories of 39 reflective markers were recorded. The resultant dataset contains a total of 1,411 recordings, with 3,229 single kicks and punches. The recordings are available in C3D file format. The dataset provides the opportunity for kinematic analysis of different combat sport techniques in attacking and defensive situations.

Convolutional neural network in upper limb functional motion analysis after stroke.

In this work, implementation of Convolutional Neural Network (CNN) for the purpose of analysis of functional upper limb movement pattern was applied. The main aim of the study was to compare motion of selected activities of daily living of participants after stroke with the healthy ones (in similar age). The optical, marker-based motion capture system was applied for the purpose of data acquisition. There were some attempts made in order to find the existing differences in the motion pattern of the upper limb. For this purpose, the motion features of dominant and non-dominant upper limb of healthy participants were compared with motion features of paresis and non-paresis upper limbs of participants after stroke. On the basis of the newly collected data set, a new CNN application was presented to the classification of motion data in two different class label configurations. Analyzing individual segments of the upper body, it turned out that the arm was the most sensitive segment for capturing changes in the trajectory of the lifting movements of objects.

Neuromuscular, Perceptual, and Temporal Determinants of Movement Patterns in Wheelchair Fencing: Preliminary Study.

The objective of the present study was to determine the structure of the movement pattern performed during a wheelchair fencing lunge that is executed in response to visual and sensory stimuli. In addition, a comparison was made between fencers in the categories A and B of disability. In addition, the analysis involved the correlation between the duration of the sensorimotor response and the value of the bioelectric signal recorded in selected muscles. Seven Paralympic team athletes specializing in wheelchair fencing (3 in category A and 4 in category B) participated in the research. The fencers perform at international level competitions and are multiple medalists of the Paralympic Games. In the study, a wireless system for sEMG and accelerometer signal measurement was employed to test the intervals between the initiation of the lunge attack and its termination defined by the touch of the weapon on the coach's torso. The electrodes were placed on 9 key muscles responsible for the effectiveness of the executed attack: DEL, TRI, BC, ECR FCR, LD, and EAO. The significant intergroup difference in the muscle activation was found to be 0.333 s for category A fencers and 0.522 s for category A fencers at p = 0.039 applies to the latissimus dorsi (LD LT) muscle, which demonstrates its significance as a postural muscle in the structure of the examined movement pattern. In terms of the values of EMG, a tendency for higher MVC (%) values in most muscles for category A competitors was recorded. The latissimus dorsi (DL RT) muscle with an intergroup difference of MVC-114.63 for cat. A and 67.50 for cat. B at p = 0.039 turned out to play a significant role. The results prove the role of postural muscles: external abdominal oblique and latissimus dorsi on the effectiveness of the attacks executed in wheelchair fencing.

Comparison of Smoothing Filters in Analysis of EEG Data for the Medical Diagnostics Purposes.

This paper covers a brief review of both the advantages and disadvantages of the implementation of various smoothing filters in the analysis of electroencephalography (EEG) data for the purpose of potential medical diagnostics. The EEG data are very prone to the occurrence of various internal and external artifacts and signal distortions. In this paper, three types of smoothing filters were compared: smooth filter, median filter and Savitzky-Golay filter. The authors of this paper compared those filters and proved their usefulness, as they made the analyzed data more legible for diagnostic purposes. The obtained results were promising, however, the studies on finding perfect filtering methods are still in progress.

Evaluation of Risk Behavior in Gambling Addicted and Opioid Addicted Individuals.

Evidence suggests that both opioid addicted and gambling addicted individuals are characterized by higher levels of risky behavior in comparison to healthy people. It has been shown that the administration of substitution drugs can reduce cravings for opioids and the risky decisions made by individuals addicted to opioids. Although it is suggested that the neurobiological foundations of addiction are similar, it is possible that risk behaviors in opioid addicts may differ in detail from those addicted to gambling. The aim of this work was to compare the level of risk behavior in individuals addicted to opioid, with that of individuals addicted to gambling, using the Iowa Gambling Task (IGT). The score and response time during the task were measured. It was also observed, in the basis of the whole IGT test, that individuals addicted to gambling make riskier decisions in comparison to healthy individuals from the control group but less riskier decisions in comparison to individuals addicted to opioids, before administration of methadone and without any statistically significant difference after administration of methadone-as there has been growing evidence that methadone administration is strongly associated with a significant decrease in risky behavior.

sEMG Activation of the Flexor Muscles in the Foot during Balance Tasks by Young and Older Women: A Pilot Study.

OBJECTIVE: In this publication, we suggest that young adults and seniors use various defense mechanisms to counteract loss of balance. One of the hypotheses is the change in the coordination of antagonistic muscle groups, especially within the ankles. In this study, we tried to determine if there is a relationship between the condition from resilient, to pre-frail, to frail and the ability to maintain balance during free standing and balance tasks. The aim of the study was to define the importance of muscle activity in the ankle joint, dorsal flexor of the foot for the following: tibialis anterior (TA), plantar flexor of the foot gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and peroneus longus (PER), during balance tasks with eyes open (EO) and closed (EC). We hypothesized that there are differences in the activity and co-activation of the tested muscles in young and older women, which may indicate an increased risk of falls and walking disorders. MATERIALS AND METHODS: A group of 20 women qualified for the study. The group was divided into two subgroups, young (G1) and elderly women (G2). The aim of the study was to define the importance of muscle activity in the ankle joint, dorsal flexor of the foot for the following: tibialis anterior (TA), plantar flexor of the foot gastrocnemius medialis (GM), gastrocnemius lateralis (GL), and peroneus longus (PER), during balance tasks with eyes open (EO) and closed (EC). RESULTS: In this study, we observed significant differences between groups in the maximum and mean values of electromyography activity (EMG) activation of the examined muscles on different types of surfaces and with open and closed eyes. Older women generated higher values of EMG activation in all muscles except the gastrocnemius medialis muscle. The results were significant for co-activation at rest for muscles as follows: tibialis anterior and gastrocnemius medialis with eyes closed (p = 0.01) and peroneus and gastrocnemius lateralis at rest with eyes open (p = 0.03), eyes closed (p = 0.04), and on a foam (p = 0.02). The sEMG amplitude of the tested muscles means that agonist muscle activity changed relative to antagonistic muscle activity. CONCLUSIONS: Activation of sEMG and coordination of ankle muscles during balance tasks change with age. It can be hypothesized that assessment of balance during free standing and equivalent tasks can predict the state of frailty, after taking into account other physiological variables that are believed to affect balance control.

Kinematic Analysis of Mae-Geri Kicks in Beginner and Advanced Kyokushin Karate Athletes.

Background: Each of the techniques used in sport is a complex technique requiring a combination of neuromuscular conduction, motor anticipation, and extremely developed proprioception. This is especially the case in martial arts when we deal with a kick or a blow to a specific target. Methods: The main purpose of this study was to determine the kinematic differences in the tested movement pattern among athletes with different levels of advancement in the conditions of kicking: in the air, at a target (a shield), and in direct contact with a competitor. Comparative analysis was performed among 26 players: 13 advanced (group G1) and 13 beginners (group G2). Kinematic data was recorded using an optical motion capture system. The examination consisted of performing three tests of mae-geri kick in sequences of three kicks in three different conditions (without a target, with a static target, and with an opponent). The examination was performed with the back leg and only the moment of kick was analyzed. Results: The most significant differences were observed in the movement of head, torso, hip, knee, and ankle segments, especially during a kick at a shield. Based on the conducted analysis, we can assume that karate training changes the strategy of neuromuscular control, promoting improvement of mobility pattern efficiency. Conclusion: Acquiring this type of knowledge can lead to better results, elimination of errors in training, especially in the initial period of training, and the prevention of possible injuries that occur during exercise or competition.

Flèche versus Lunge as the Optimal Footwork Technique in Fencing.

The objective of the study reported in this paper involved identifying the fencing attack (flèche versus lunge) that provides greater effectiveness in a real competition. Two hypotheses are presented in the study. The first hypothesis involves the greater effectiveness of the flèche with regard to bioelectric muscular tension, and the second hypothesis involves the reduction of movement time of the flèche. Therefore, analyses were conducted by the application of EMG (electromyography) signal, ground reaction forces, and parameters representing sensorimotor responses (RT-reaction time and MT-movement time). This study included six world-leading female épée fencers (mean age: 24.6 ± 6.2 years). Throughout the procedure, the subjects performed flèche and lunge touches at the command of the coach based on visual stimuli. The experimental results indicated the greater effectiveness of the flèche compared with the lunge with regard to increases in EMG values (p = 0.027) in the lateral and medial gastrocnemius muscles and decreases in the duration of the movement phase (p = 0.049) and vertical force of the rear leg (p = 0.028). In conclusion, higher levels of EMG and ground reaction forces were generated during the flèche compared with the lunge, which promotes an improvement in the explosive force and contributes to a reduction in the movement phase of the entire offensive action.

Analysis of Ankle sEMG on Both Stable and Unstable Surfaces for Elderly and Young Women-A Pilot Study.

Body aging is frequently accompanied with numerous consequences such as increased tendency to falls, which may be connected not only with the impaired ability of keeping balance, but also with some limitations of the system responsible for the maintenance of balance. The aim of this study was defining the importance of muscle activity in the ankle joint when standing on stable and unstable surfaces with eyes open and closed as well as examining indications of the influence of body aging on the activity of the selected muscles. The study was carried out on a group of 20 healthy women divided into two age groups (aged 24 ± 3.6 years and aged 64 ± 4.2 years). The activity of muscles stabilizing the ankle joint while standing on different types of surfaces was tested with an EMG (surface electromyography) on both elderly and young women during trials with open and closed eyes. The tests showed higher activation in the evaluated muscles of the anterior group (tibialis anterior (TA), peroneus longus (PL)) of elderly women. For the posterior shin muscles of both groups, a higher activation was observed in the gastrocnemius lateralis muscle (GL) of elderly women, whereas gastrocnemius medialis muscle (GM) showed highly comparable activity. The results obtained in this work confirm the importance of proprioception training and muscle strength in the rehabilitation of older people as well as in prophylactic exercise aimed toward the prevention of ankle injuries.

Functional differences in upper limb movement after early and chronic stroke based on kinematic motion indicators.

AIMS: The main purpose of this study was to determine the changes in kinematic parameters of ischemic stroke affected upper limbs, during simple functional activity, to determine the most relevant changes. METHODS: The OptiTrack system was used for motion capture. To determine upper extremity function in Activities of Daily Living (ADL) tasks. During particular phases, the following matrices were chosen: mean and peak speed, normalized movement unit, normalized jerk and phase movement time. The chosen matrices represent the speed and smoothness profile of end-point data. The the arm-trunk compensation was also taken into consideration. Twenty stroke patients, in early (G1 from 1 to 3 months after stroke) and chronic stage (G2 from 6 months to 1 year), were studied. The large and small cylinder forward and back transporting phases were evaluated. RESULTS: The most significant differences between groups G1 and G2 were in mean and peak speed of the forward transport of the large and small cylinders for the paretic limb. Significant differences were also found for the smoothness (measured by movement unit, mean and peak speed and jerk) where the G2 group had a rougher motion. There were also differences in arm-trunk compensation in the frontal plane. CONCLUSION: The variables used in the study showed applicability in assessing kinematic parameters in both the early and chronic period after stroke.

Coordination Aspects of an Effective Sprint Start.

The aim of the present study was to examine differences in the movement structure and the coordination aspects expressed by bioelectrical tension indicators between a group of experts/sprinters and a group of novices/students. A group consisted of 20 sprinters and a control group consisted of 35 master's physical education students. A 16-channel surface electromyography (14 muscles) and two cameras with recording speed of 250 frames/per second were used. Significant differences were found between reaction time (p < 0.005) and time at 30 m of the covered sprinting distance (p < 0.001) between the students and advance athletes. Furthermore, the sprinters activated the back foot (taking off the starting blocks) and the front foot (first ground contact) earlier, which correlated with the attained times at 5 (r = 0.66) and 10 m (r = 0.62) of the covered sprinting distance. The most important component of the sprint start, apart from the muscle strength of the legs, is the appropriate motor coordination, which greatly affects the generation of power in the legs at the right time and optimal duration.

BOLD fMRI signal in stroke patients and its importance for prognosis in the subacute disease period - Preliminary report.

Functional magnetic resonance imaging (fMRI) allows for the assessment of neuronal activity through the blood-level-dependent signal. The purpose of study was to evaluate the pattern of brain activity in fMRI in patients with ischemic stroke and to assess the potential relationship between the activity pattern and the neurological/functional status. METHODS: The fMRI was performed in patients up to 4th day of stroke. All the patients were analyzed according to NIHSS on 1st day and mRankin scale on 14th day of stroke, followed by analyzing of fMRI signal. RESULTS: The study enrolled 13 patients at a mean age of 64.3years. Eight (61.5%) showed cerebellar activation and 2 (15.38%)- insular activation. In those who scored 0-2 on mRankin scale, the most frequently observed activity was located in the regions: the M1, SMA and PMC in the stroke hemisphere and the cerebellum. In those cases, the non-stroke hemisphere was more frequently involved in the areas: the M1 and PMC. There was a tendency for a better prognosis in relation to age <65years and activation of the SMA in the stroke hemisphere. CONCLUSION: There are differences observed in the activation areas of the cerebral cortex both in the stroke and non-stroke hemispheres. More than half of the patients with hemispheric stroke but all with good outcome showed cerebellar activation. There is probable positive correlation between the BOLD-signal size, young age, activation of supplementary motor area in stroke hemisphere and good functional status of patients in the subacute period of stroke.