Relationship between Isokinetic Knee Strength and Speed, Agility, and Explosive Power in Elite Soccer Players

The aim of this study was to determine the relationship between the isokinetic characteristics of knee extensors and flexors with selected motor abilities: Speed, agility, and explosive power of lower extremities of professional football players in the preparation period of a yearly training cycle. Twenty-one players (age: 24.5 ± 3.9 years; body mass: 76.7 ± 4.7 kg and body height: 183.5 ± 5.5 cm) playing in the highest Polish soccer league participated in the study. The isokinetic concentric torque of the knee extensors and flexors was measured at 300°/s, 180°/s, and 60°/s velocities. Sprint performance was assessed in the 30 m sprint test (standing start). The forward, lateral, and backward movements were assessed using the T-Test of agility. Explosive power was quantified by performing the squat jump (SJ) and countermovement (CMJ), using the force platform. Due to sport-specific demands of soccer activities measured in this experiment, the relationships between peak torque (PT) and the 30 m sprint, T-Test of agility, and power of vertical jumps (SJ and CMJ) were low or medium at speeds of 60°/s and 300°/s. One of the main reasons for the lack of high dependence of the above-mentioned factors are that the measurements were performed during the initial training period where the level of individual abilities is at a low level. Additionally, this experiment may also indicate that the measurement of isokinetic knee flexion and extension peak is effective when performed at the correct angular velocity in relation to the evaluation of the intended motion structure.

Structure in motion: visual motion perception as online hierarchical inference

Identifying the structure of motion relations in the environment is critical for navigation, tracking, prediction, and pursuit. Yet, little is known about the mental and neural computations that allow the visual system to infer this structure online from a volatile stream of visual information. We propose online hierarchical Bayesian inference as a principled solution for how the brain might solve this complex perceptual task. We derive an online Expectation-Maximization algorithm that explains human percepts qualitatively and quantitatively for a diverse set of stimuli, covering classical psychophysics experiments, ambiguous motion scenes, and illusory motion displays. We thereby identify normative explanations for the origin of human motion structure perception and make testable predictions for new psychophysics experiments. The algorithm furthermore affords a neural network implementation which shares properties with motion-sensitive cortical areas and motivates a novel class of experiments to reveal the neural representations of latent structure.

Time-motion analysis in elite female Wushu Sanda athletes according to competitive phases and weight categories

Introduction: Wushu Sanda is a Chinese combat sport. Objective: To measure the time-motion structure of elite female wushu sanda athletes during the 13th World Wushu Championships in different weight divisions (light, middle, and heavy categories) and competition phases (eliminatory, quarterfinals, semifinals and finals). Material and methods: Fifty-five female athletes from 31 countries participated in 46 matches during the competition. All 46 matches, accounting 95 rounds, 35 in light, 25 in middle and 35 in heavyweight divisions, took part in the study. Matches were analyzed using the software Kinovea™. Each match was reproduced in slow motion (50%) twice; therefore, one athlete was observed each time to ensure that all activities would be registered, totalizing 92 observations (46 matches, 2 observations per match). We registered the time in observation, preparation, interaction, effort, pause, high-intensity and low-intensity activities. Results: Descriptive data showed an effort:pause ratio of 2.2:1, a high:low intensity efforts ratio of 1:1.3, and mean observation-preparation-interaction times of 4.5-1.2-4.2 seconds. When comparing by weight category, heavyweight categories had higher total fighting time per round than the light and middle categories. Also, heavyweight categories had longer preparation and interaction mean-time; and referee interruption time frequency, total and mean times than the light and middle categories. Total pause time was also higher for heavyweights. According to the competitive phase, semifinal matches had shorter observation times than eliminatory and final matches. Also, semifinal matches had lower low-intensity time than quarterfinals and finals. Conclusions: Wushu sanda is an intermittent combat sport, and female athletes present some time-motion differences according to weight division and competitive phase.

STRUKTUR GERAK TARI LURAH KINCIA DI SANGGAR TARI LURAH KINCIA NAGARI SITUJUAH BATUA KECAMATAN SITUJUAH LIMO NAGARI KABUPATEN 50 KOTA

This study aims to describe and analyze the structure of the dance movement of Lurah Kincia dance in Situjuah Batua village, Situjuah Limo Nagari district, 50 Kota regency. This study belongs to a qualitative research using analytical descriptive method. The data used in this study were primary and secondary data. The main instrument used was the researcher itself and was assisted by supporting instruments such as writing instruments, cameras, and flash drives. The data were collected through literature study, observation, interview, and documentation. The data analysis was conducted by collecting the data, describing the data, analyzing the data, and making conclusions. The results showthat the movement structure of Lurah Kincia dance has basic elements related to the attitude and movement of the body parts starting from the head, body, hands, and feet. From the relationship system between those elements, it produces motive forms in the form of turn taking, and are related to each other like a chain.The hierarchical grammatical relationship system contained in Lurah Kincia Dance consists of 37 motifs, 6 phrases, 4 sentences, and 1 cluster. Lurah Kincia dance belongs to a syntagmatic relationship system. It is a system whose relationship is like a chain and cannot be separated or exchanged between one another.Keywords: Motion Structure, Lurah Kincia Dance, Lurah Kincia Dance Workshops

STRUKTUR GERAK TARI TAMPURUANG DI NAGARI BATU MANJULUA KECAMATAN KUPITAN KABUPATEN SIJUNJUNG PROVINSI SUMATERA BARAT

This study aims to describe and analyze the motion structure of Tampuruang dance in Batu Manjulua village, Kupitan district, Sijunjung regency, West Sumatra province.This research belongs to a qualitative research. The types of data used were primary and secondary data. The main instrument in this research was the researcher itself and was assisted by supporting instruments such as writing tools, cameras, and flash drives. The data were collected through literature study, observation, interview, and documentation. The steps of analyzing the data was collecting the data, describing the data, and concluding the data.The results show that 1) related to the relationship system of basic elements, Tampuruang Dance has motions of body parts consisting of the head, body, hands, and feet. From the relationship system between the elements above, it produces the form of motives which are alternate and interrelated like a chain, 2) Related to the hierarchical grammatical relationship system, Tampuruang Dance consists of 42 motifs, 8 phrases, 5 sentences, and 1 cluster, 3) Tampuruang dance belongs to a syntagmatic relationship system which is like a chain, and it cannot be separated or exchanged between one another.Key words: Motion Structure, Tampuruang Dance, Batu Manjulua Village

Human visual motion perception shows hallmarks of Bayesian structural inference

Motion relations in visual scenes carry an abundance of behaviorally relevant information, but little is known about the computations underlying the identification of visual motion structure by humans. We addressed this gap in two psychophysics experiments and found that participants identified hierarchically organized motion relations in close correspondence with Bayesian structural inference. We demonstrate that, for our tasks, a choice model based on the Bayesian ideal observer can accurately match many facets of human structural inference, including task performance, perceptual error patterns, single-trial responses, participant-specific differences, and subjective decision confidence, particularly when motion scenes are ambiguous. Our work can guide future neuroscience experiments to reveal the neural mechanisms underlying higher-level visual motion perception.

1. The science of softness

‘The science of softness’ provides a brief history and overview of soft matter science. The development of soft matter science was propelled by a combination of communication within the scientific community; intrinsic conceptual overlap and commonality; and visionary leadership from a small number of pioneering scientists. Chemistry proved as essential an ingredient to the new science of soft matter as ideas and techniques from physics. The characteristics of soft matter include motion; structure on intermediate length scales; slow dynamics; and universality. Microscopy is the most obvious and direct example of experimental tools applied across the gamut of soft materials.

ANALISIS STRUKTUR GERAK TARI ZAPIN SIAK DI KECAMATAN SIAK KABUPATEN SIAK PROVINSI RIAU

Zapin Siak dance is a traditional Malay dance which has been cultured, lived, and developed in line with human life from time to time. Zapin Siak dance is danced by two male dancers taking parallel position in a form of motion which generally uses a lot ofThis is a qualitative research using a content analysis method, known as content analysis. The object of research was Zapin Siak Dance in Kampung Dalam Subdistrict, Siak District, Siak Regency, Riau Province. The data used were primary and secondary data. The data were collected through literature study, observation, interview, and documentation. The research instrument used was the researcher itself and was assisted by writing instruments, cameras, and flash drives. The data analysis was done by describing and interpreting various movements of the Zapin Siak dance. It refers to the elements of motion: the head, body, hands, andThe results show that the movement structure of Zapin Siak Dance in Siak District, Siak Regency, Riau Province, consists of 22 kinem elements, 22 morphokinem elements, 7 motif elements, and one overall dance form, namely Zapin Siak dance. Zapin Siak dance has a syntagmatic relationsip between the motif level and a paradigmatic relationship in overall dance.Keywords: Analysis, Motion Structure, Zapin Siak Dance