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.

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.

This study characterizes high-altitude training camps and their effect on the aerobic capacity of a Polish national team member (M.W.), who was a participant in the PyeongChang 2018 Winter Olympic Games (body weight: 59.6 kg, body height: 161.0 cm, fat mass: 10.9 kg and 18.3% of fat tissue, fat-free mass: 48.7 kg, muscle mass: 46.3 kg, and BMI = 23.0 kg/m2). The tests were conducted in the periods from April 2018 to September 2018 and April 2019 to September 2019 (period of general and special preparation). The study evaluated aerobic and anaerobic capacity determined by laboratory tests, a cardiopulmonary graded exercise test to exhaustion performed on a cycle ergometer (CPET), and the Wingate anaerobic test. Based on the research, training in hypobaric conditions translated into significant improvements in the skater’s exercise capacity recorded after participating in the Olympic Winter Games in Korea (February 2018). In the analyzed period (2018–2019), there was a significant increase in key parameters of aerobic fitness such as anaerobic threshold power output (AT-PO) [W]—223; power output POmax [W]—299 and AT-PO [W/kg]—3.50; (POmax) [W/kg]—4.69; and AT-VO2 [mL/kg/min]—51.3; VO2max [mL/kg/min]—61.0. The athlete showed high-exercise-induced adaptations and improvements in the aerobic metabolic potential after two seasons, in which four training camps were held in altitude conditions.

Dedicated to Prof. Vladimir Prelog on the occasion of his 90th birthday (7.111.96) ~ ~~An efficient synthesis of the two title compounds is reported, as well as their X-ray crystal-structure analyses. A discussion based on stereoelectronic considerations rationalizes the first example of a crystalline SO,/C(O) syn-periplanar conformer of a N-acylbornane-l0,2-sultam.We have recently reported the diastereoselective [4 + 2 1 cycloaddition of 1 -methoxybuta-1,3-diene to (2R)-N-glyoxyloylbornane-10,2-sultam (la)') under high pressure and/ or in the presence of catalytic amounts of [Eu(fod),] [6]. To study the scope and limitation of this kind of hetero-Diels-Alder reaction3), we prepared the homologous dienophiles (-)-lb, c4) which are also important chiral precursors for nucleophilic additions'). For a recent review on asymmetric intermolecular homo-and hetero-Diels-Alder reactions, see [7]. For an independent and recent synthesis of (-)-lb, isolated as a gum and presented without chiroptical data, see [8].For the diastereoselective reduction of N-pyruvoyl-and N-(phenylglyoxyloyl)amides, see [9].

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.

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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.

The purpose of the work was to characterize the 4-year preparation cycle for the Winter Olympic Games in Pyongyang (2018), the leading Polish speed skater M.W. Longitudinal tests included assessment of aerobic and anaerobic exercise capacity determined in laboratory tests, respectively in the graded bicycle ergometer test and in the Wingate test performed with the lower extremity. The longitudinal data from exercise tests obtained in the analyzed 4-year period of preparation for the Olympic Games clearly indicate a significant improvement in the skater's exercise capacity. In the examined period of 2015-2018, the athlete obtained an increase in VO2max value by 6.5% to the level of 55.8 ml/kg/min. The nature of the observed changes in selected exercise indicators corresponded to the assumptions and implementation of training plans. The examined athlete was very well prepared for qualifying starts in October-November 2017 and she won three Olympic qualifications at distances 500, 1000 and 1500 m. During the Olympic Games, the Polish representative started the competition with starts at distances 1500 (20th place) and 500 m (28th place). At the leading distance of 1000 m, the competitor started at her level, reaching 12th place thus fulfilling the pre-start assumptions.