Determination of fighting styles of qualified veteran boxers based on cluster analysis of biomechanical and psychophysiological indicators

Purpose: to reveal the styles of fighting veteran boxers on the basis of a multivariate analysis of psychophysiological and biomechanical indicators. Material and methods. The study involved 42 qualified veteran boxers (age 45-50 years). As research methods, we used a biomechanical analysis of the indicators of the speed of movement of various points and the values ​​of the angles in the joints when performing a direct blow by boxers. The psychophysiological method was used to determine the time of a simple and complex reaction under standard conditions and in various testing modes. We used the method of cluster analysis to distribute athletes into groups using the SPSS - 17.0 program. Within the groups, the athletes are as similar as possible to each other in terms of the analyzed indicators, and between the groups they differ as much as possible. The analysis of the groups of athletes obtained with the help of cluster analysis made it possible to identify athletes with the following styles of fighting: tempo, game, power. Results. Cluster analysis of psychophysiological and biomehanical testing showed the presence of 3 groups of athletes. The clusters were named as follows: Cluster 1 - "Speed and coordination endurance", corresponds to the boxers of the pace of the fight; Cluster 2 - "Speed", corresponds to the boxers of the game style of fighting; Cluster 3 - "Strength and speed", corresponds to the boxers of the pace of the fight. Biomechanical features of boxers of different styles of fighting are reflected in the trajectories of the points of the fist, elbow, knee. Conclusions. The results of this study should be used when planning the individual training of athletes in boxing and to determine the optimal style of competitive competition for qualified veteran boxers. The proposed methods of psychophysiological and biomechanical testing to determine the individual characteristics of boxers are an effective, fairly accessible and convenient tool for revealing the predisposition of boxers to a certain style of fighting.

Spinopelvic fixation: modern technical solutions

The paper presents the second part of literature review devoted to modern techniques of spinopelvic fixation for various pathologies of the spine and injuries to the spine and pelvis. The review is non-systematic and was conducted using PubMed and eLibrary databases of medical literature. Modern techniques of spinopelvic fixation using screws installed in the ilium are highlighted, including anatomical and biomechanical features, clinical results of application, as well as the implementation of spinopelvic fixation for tumor lesions of the sacrum, including the use of customized implants and additive technologies. The features of classical installation of iliac screws and installation by the S2AIS technique are considered, and their advantages and disadvantages and possible complications are evaluated.

Kinetic and Kinematic Features of Pedestrian Avoidance Behavior in Motor Vehicle Conflicts

The active behaviors of pedestrians, such as avoidance motions, affect the resultant injury risk in vehicle–pedestrian collisions. However, the biomechanical features of these behaviors remain unquantified, leading to a gap in the development of biofidelic research tools and tailored protection for pedestrians in real-world traffic scenarios. In this study, we prompted subjects (“pedestrians”) to exhibit natural avoidance behaviors in well-controlled near-real traffic conflict scenarios using a previously developed virtual reality (VR)-based experimental platform. We quantified the pedestrian–vehicle interaction processes in the pre-crash phase and extracted the pedestrian postures immediately before collision with the vehicle; these were termed the “pre-crash postures.” We recorded the kinetic and kinematic features of the pedestrian avoidance responses—including the relative locations of the vehicle and pedestrian, pedestrian movement velocity and acceleration, pedestrian posture parameters (joint positions and angles), and pedestrian muscle activation levels—using a motion capture system and physiological signal system. The velocities in the avoidance behaviors were significantly different from those in a normal gait (p < 0.01). Based on the extracted natural reaction features of the pedestrians, this study provides data to support the analysis of pedestrian injury risk, development of biofidelic human body models (HBM), and design of advanced on-vehicle active safety systems.

Structural and biomechanical properties and trace elements composition of the corneoscleral eye shell in normal tension glaucoma

The results of comparative studies of the structural and biomechanical features of the corneoscleral eye shell in various clinical forms of glaucoma are presented. The article discusses how the systemic and local imbalance of trace elements that regulate collagen biosynthesis, the formation of cross-links in the connective tissue structures of the sclera, and the hydrodynamics of the intraocular fluid, affect the intraocular pressure level, and thereby the character of the development of glaucomatous lesions in normal tension glaucoma. Modern literature is shown to indicate the prospects for further research in this direction.

Spinopelvic fixation: indications, anatomical and biomechanical aspects and historical development of methods

A review of the literature on performing spinopelvic fixation for injuries and various pathologies of the spine and pelvis is presented. The review is analytical in nature and was carried out using databases of medical literature and search resources of PubMed and eLibrary. The following aspects are highlighted: the relevance and indications for performing spinopelvic fixation and its anatomical and biomechanical features. The historical aspects of the development of methods for performing spinopelvic fixation are considered and structured. The analysis of various methods of spinopelvic fixation (using hooks, screw insertion into the S2 sacral wings, L-shaped Luque rods, distractors, transiliac rods, Jackson, Harrington and Galveston techniques) was carried out. The features of surgical techniques, their advantages, disadvantages and complications are considered.

Simulation of the movement of the supporting leg of an exoskeleton with two links of variable length in 3D

A two-link model of exoskeleton with variable-length links for supporting the lower limbs of the human musculoskeletal system is proposed in the article. The researched model differs from the existing ones by the variable-length links, and by the angle calculation method. While in the existing models, the angles are calculated from the regular direction – from vertical, or from horizontal, – in the proposed research they are calculated between the links. As for practical exoskeleton implementation, the proposed method of angle calculation is appropriate to the actual working conditions of the electrical motors with the reduction gears installed in the hinges, which change the angles between the links. The construction of a variable-length exoskeleton link consists of two absolutely solid weighty sections located at both ends of the link and one weightless section between them in the center of the link. In the weightless section, there is a drive that creates a control longitudinal force, which realizes the increase or decrease in the length of the link in the required manner and provides the necessary maintenance of the length of the link when the person moves in the exoskeleton. The links are connected to each other using spherical hinges. Drives are installed in each hinge, creating control torques, which provide a relative rotational movement of the links. The jointly controlling longitudinal forces and moments realize the maintenance of the posture or the movement of the link in the required manner and, in relation to the exoskeleton, the repetition of the basic biomechanical properties of the human musculoskeletal system. The mathematical model in the form of the system of Lagrange differential equations of the second kind is obtained. The obtained mathematical model is examined for existence and uniqueness of the Cauchy solution. The kinematic trajectory of the link motion has been synthesized, which simulates the anthropomorphic movement of the supporting leg during the single-support phase of movement, and the control actions required for its implementation has been found. The significance of the results obtained in the process of modeling lies in the ability to create active exoskeletons, prostheses in medicine, anthropomorphic robots, and spacesuits that take into account the biomechanical features of the functioning of the human musculoskeletal system.

Kinematics and joints moments profile during straight arm press to handstand in male gymnasts

Biomechanical features of the handstand, one of the most fundamental skills required for artistic gymnastics events, have not been well documented. The purpose of this study was to clarify the kinematics and joint moment profiles during straight arm press to handstand in different highly skilled male gymnasts. Fifty-nine male gymnasts performed a straight arm press to handstand on a force platform and were judged on their performance by experienced certified judges. Subjects were divided into two groups (highly-skilled and less-skilled). Kinematic data were obtained using a video camera synchronized with force platform. Joint moments (wrist, shoulder, hip) during each straight arm press to handstand were calculated using the inverse dynamics solution. Larger shoulder flexion moments were observed in less-skilled compared with highly- skilled performers (at 3–59%, p < 0.001) while larger hip flexion moments were observed in highly- skilled performers at 52% (p = 0.045) and 56% (p = 0.048) and normalized time of straight arm press to handstand. Major differences between highly-skilled and less-skilled performers were observed in hip joint moment production as it shifted from extension to flexion from the leg horizontal position to the handstand position in highly-skilled gymnasts. Successful straight arm press to handstand techniques observed in highly-skilled performers were characterized as a more acute pike position at toe-off as well as hip flexor moments at latter phase of the straight arm press to handstand.

Comparative Analysis of Constructive, Clinical and Biomechanical Features of Screw, Bone and Combined Dental Implant Chuiko-Alymbaev

This work is devoted to a comparative analysis in the context of the structural, clinical and biomechanical features of three types of dental implants: screw, bone and combined (Chuiko-Alymbaeva). A description of the strengths and weaknesses of each type of implant.

Guidelines for the measurement of vascular function and structure in isolated arteries and veins

The measurement of vascular function in isolated vessels has revealed important insights into the structural, functional, and biomechanical features of the normal and diseased cardiovascular system, and has provided a molecular understanding of the cells that constitutes arteries and veins and their interaction. Further, this approach has allowed the discovery of vital pharmacological treatments for cardiovascular diseases. However, the expansion of the vascular physiology field has also brought new concerns over scientific rigor and reproducibility. Therefore, it is appropriate to set guidelines for the best practices of evaluating vascular function in isolated vessels. These guidelines are a comprehensive document detailing the best practices and pitfalls for the assessment of function in large and small arteries and veins. Herein, we bring together experts in the field of vascular physiology with the purpose of developing guidelines for evaluating ex vivo vascular function. By utilizing this document, vascular physiologists will have consistency amongst methodological approaches, producing more reliable and reproducible results.

Effects of Masai Barefoot Technology Footwear Compared with Barefoot and Oxford Footwear on Gait

Background Shoes, with their biomechanical features, affect the human body and function as clothing that protects the foot. This study aimed to investigate the effects of Masai Barefoot Technology (MBT) shoes on gait in healthy, young individuals compared with bare feet and classic stable shoes. Methods The study was conducted in 67 healthy females aged 18 to 30 years. All volunteers walked barefoot, in Oxford shoes, and in MBT shoes and were evaluated in the same session. Kinematic gait analyses were performed. The three performances were compared using repeated-measures analysis of variance to study the variance in the groups themselves, and the Friedman and Wilcoxon paired two-sample tests were used for the intragroup comparisons. Results We found that the single support time and the swing phase ratio increased during walking in MBT shoes compared with walking in stable shoes, whereas the double support ratio, stride length, cadence, gait speed, loading response ratio, and preswing phase ratio decreased. However, it was found that the step and stride length, step width, and gait speed increased and the preswing phase extended during walking in stable shoes compared with walking barefoot. Conclusions These results support the hypothesis that MBT shoes facilitate foot cycles as they reduce the loading response and the preswing and stance phase ratios.