Search Results (38)

Archery has increasingly captivated attention in its use for rehabilitation and physical education due to its adaptability for various abilities. However, this repetitive sport carries some injury risk in the shoulder, elbow, and back during the draw and release phases. While research often explores factors affecting shooting performance, limited studies have examined the interplay between gender-specific biomechanics and bow-related variables on lumbar stress and shooting mechanics. This study addresses this gap by leveraging the Xsens MVN Awinda motion capture system and JACK Siemens ergonomic software to analyze full-body movements of archers with different experience levels, bow types, and target placements. Thirteen subjects participated in this investigation, each equipped with standard gear. We analyzed their posture throughout the shooting sequence and the forces acting on their lower back. This innovative approach streamlines data collection and eliminates the need for extensive prototyping. Our findings highlight natural biomechanical adaptations between males and females when using bows of varying draw weights. Males generally exhibited greater consistency and stability, while females showed increased variability, particularly with heavier bows. This research establishes a foundation for ergonomic and reproducible archery techniques, enabling individualized training and performance optimization strategies. Full article

Ballet is a discipline that combines art and sport in a harmonious way. It is a practice that has high physical and mental demands to achieve the proper body precision. During this activity, numerous muscles, including those in the legs, need to be exercised. Therefore, individuals who have lost part of their lower limb due to amputation face numerous significant challenges when it comes to practicing ballet. Throughout this article, the key aspects that influence the design of a lower limb prosthesis specifically adapted for ballet practice will be analyzed. New materials will be explored with the goal of designing an optimal model that ensures maximum performance and comfort for the users. Additionally, the prosthesis will be customized using 3D-printing technology, and a prototype will be presented. This study will merge biomechanics, ergonomics, and design. Its goal is to find a solution that improves the quality of life for lower limb amputees whose passion is ballet. The aim is to overcome physical and emotional barriers and provide a way to reintegrate amputee dancers into the world of dance. It is important to highlight the novelty of this work: combining different disciplines to provide a solution for individuals who engage in dance as a hobby rather than professionally. The proposed methodology aims to enable users with disabilities to access a personalized, complex, and potentially costly product. Full article

Manual dynamometry (HHD) allows for the assessment of musculature because its use has been supported as an indicator of health in different population groups. The objective of this study was to examine the reliability and validity of the Activ5 dynamometer for assessing grip strength in a population of adults. A total of 106 individuals with an age of 20.38 ± 1.64, body mass of 71.52 ± 11.32 kg, and height of 1.70 ± 0.11 m were evaluated during two sessions. A cross-sectional agreement study was conducted on Sports Science students from a university community, and 106 individuals were evaluated during two sessions. Statistical analysis of reliability and validity was performed using intraclass correlation coefficients (ICCs), Pearson correlations, and Lin’s coefficient. According to Lin’s coefficient, both instruments measure grip strength for both conditions, either for the right hand or the left hand. The correlation coefficient to determine the linear relationship between both instruments determined that between the Jamar right-hand dynamometer and the right-hand Activ5, a coefficient R² = 0.580, p = 0.00, was obtained. In contrast, the correlation between the Jamar left-hand dynamometer and the left-hand Activ5 had a coefficient R² = 0.543, p = 0.001. Both intraclass correlation coefficients and Cronbach’s alpha presented high values, indicating that both instruments have good reproducibility in their measurements. The Activ5 dynamometer cannot be used interchangeably with the Jamar dynamometer; however, the close values reported make it a reliable tool in grip strength assessment. The different characteristics of the Activ5 instrument, such as its ergonomics, weight, portability, wireless connection, dimensions, and applications, make it a promising daily- use tool for assessing, monitoring, and the prescription of physical activity and exercise. Full article

Fitts’ law, a predictive model for motor task completion time, is widely utilized in human–computer interaction (HCI) research. While its formulas in two dimensions have achieved consensus over the decades, research diverges on its application in three dimensions. This paper synthesizes practical applications across touchscreens, virtual reality (VR), pedals, handheld devices, etc., with a specific emphasis on enhancing interaction experiences for vulnerable populations. This review studies Fitts’ law’s applicability in diverse interaction scenarios, highlighting design considerations for touchscreens and handheld/foot-held devices. This article underscores the need for future research to explore three-dimensional applications and consider user age, with potential expansions into medical and sports domains. This systematic review aims to empower designers in crafting more ergonomic products and improving HCI experiences. Full article

Human Activity Recognition (HAR) plays an important role in the automation of various tasks related to activity tracking in such areas as healthcare and eldercare (telerehabilitation, telemonitoring), security, ergonomics, entertainment (fitness, sports promotion, human–computer interaction, video games), and intelligent environments. This paper tackles the problem of real-time recognition and repetition counting of 12 types of exercises performed during athletic workouts. Our approach is based on the deep neural network model fed by the signal from a 9-axis motion sensor (IMU) placed on the chest. The model can be run on mobile platforms (iOS, Android). We discuss design requirements for the system and their impact on data collection protocols. We present architecture based on an encoder pretrained with contrastive learning. Compared to end-to-end training, the presented approach significantly improves the developed model’s quality in terms of accuracy (F1 score, MAPE) and robustness (false-positive rate) during background activity. We make the AIDLAB-HAR dataset publicly available to encourage further research. Full article

Posture analysis is important in musculoskeletal disorder prevention but relies on subjective assessment. This study investigates the applicability and reliability of a machine learning (ML) pose estimation model for the human posture assessment, while also exploring the underlying structure of the data through principal component and cluster analyses. A cohort of 200 healthy individuals with a mean age of 24.4 ± 4.2 years was photographed from the frontal, dorsal, and lateral views. We used Student’s t-test and Cohen’s effect size (d) to identify gender-specific postural differences and used the Intraclass Correlation Coefficient (ICC) to assess the reliability of this method. Our findings demonstrate distinct sex differences in shoulder adduction angle (men: 16.1° ± 1.9°, women: 14.1° ± 1.5°, d = 1.14) and hip adduction angle (men: 9.9° ± 2.2°, women: 6.7° ± 1.5°, d = 1.67), with no significant differences in horizontal inclinations. ICC analysis, with the highest value of 0.95, confirms the reliability of the approach. Principal component and clustering analyses revealed potential new patterns in postural analysis such as significant differences in shoulder–hip distance, highlighting the potential of unsupervised ML for objective posture analysis, offering a promising non-invasive method for rapid, reliable screening in physical therapy, ergonomics, and sports. Full article

Archery ranks among the sports with a high incidence of upper extremity injuries, particularly affecting the drawing shoulder and elbow, as well as inducing stress on the lower back. This study seeks to bridge the gap by integrating real-time human motion with biomechanical software to enhance the ergonomics of archers. Thirteen participants were involved in four tasks, using different bows with varied draw weights and shooting distances. Through the application of advanced integrative technology, this study highlights the distinct postures adopted by both males and females, which indicate the biomechanical differences between genders. Additionally, an analysis of the correlation between exposed spinal forces and these adopted postures provides insights into injury risk assessment during the key archery movements. The findings of this study have the potential to significantly enhance the application of training methodologies and the design of assistive devices. These improvements are geared towards mitigating injury risks and enhancing the overall performance of archers. Full article

This study investigated the impact of auditory stimuli on muscular activation patterns using wearable surface electromyography (EMG) sensors. Employing four key muscles (Sternocleidomastoid Muscle (SCM), Cervical Erector Muscle (CEM), Quadricep Muscles (QMs), and Tibialis Muscle (TM)) and time domain features, we differentiated the effects of four interventions: silence, music, positive reinforcement, and negative reinforcement. The results demonstrated distinct muscle responses to the interventions, with the SCM and CEM being the most sensitive to changes and the TM being the most active and stimulus dependent. Post hoc analyses revealed significant intervention-specific activations in the CEM and TM for specific time points and intervention pairs, suggesting dynamic modulation and time-dependent integration. Multi-feature analysis identified both statistical and Hjorth features as potent discriminators, reflecting diverse adaptations in muscle recruitment, activation intensity, control, and signal dynamics. These features hold promise as potential biomarkers for monitoring muscle function in various clinical and research applications. Finally, muscle-specific Random Forest classification achieved the highest accuracy and Area Under the ROC Curve for the TM, indicating its potential for differentiating interventions with high precision. This study paves the way for personalized neuroadaptive interventions in rehabilitation, sports science, ergonomics, and healthcare by exploiting the diverse and dynamic landscape of muscle responses to auditory stimuli. Full article

The purpose of this paper is to present a procedure for automating the scanning process based on a mathematical model for a handheld 3D scanner for shoes used in some indoor sports. The study aims to use inverse kinematics to automate 3d footwear scanning used for indoor sport (handball) using a robotic arm with three joints. A modeling of the robotic arm and final effector was performed, to simulate the minimum and maximum trajectory of the robot arm according to the angles shown based on the mathematical model and inverse kinematics. With an easy-to-use interface and ergonomic design, this 3D scanning solution offers the versatility to scan various objects (such as scanning two shoe models used in indoor sports) and complex surface types. This scanning manner represents the state of the art of 3D scanning solutions as well as a benchmark in the 3D measurement equipment industry. The data obtained as a result of this research provide new directions and solutions for sports shoe scanning for indoor sports based on scanning trajectories preset by inverse kinematics in order to automate the scanning process using a handheld 3D scanner. Based on the mathematical model presented in the paper, automation of the scanning process can be achieved by maintaining the proposed trajectory using an automated arm operating through a control program that can be run on a simple controller. Full article

Force-based human posture estimation (FPE) provides a valuable alternative when camera-based human motion capturing is impractical. It offers new opportunities for sensor integration in smart products for patient monitoring, ergonomic optimization and sports science. Due to the interdisciplinary research on the topic, an overview of existing methods and the required expertise for their utilization is lacking. This paper presents a systematic review by the PRISMA 2020 review process. In total, 82 studies are selected (59 machine learning (ML)-based and 23 digital human model (DHM)-based posture estimation methods). The ML-based methods use input data from hardware sensors—mostly pressure mapping sensors—and trained ML models for estimating human posture. The ML-based human posture estimation algorithms mostly reach an accuracy above 90%. DHMs, which represent the structure and kinematics of the human body, adjust posture to minimize physical stress. The required expert knowledge for the utilization of these methods and their resulting benefits are analyzed and discussed. DHM-based methods have shown their general applicability without the need for application-specific training but require expertise in human physiology. ML-based methods can be used with less domain-specific expertise, but an application-specific training of these models is necessary. Full article

Sports activities can increase participants’ risk of orofacial trauma. Therefore, it is crucial to have a comprehensive understanding of various types of sports mouthguards. This study aims to present a narrative literature review on ergonomic mouthguards, including their indications for use, classifications, materials, manufacturing methods, and the current status of additive manufacturing in their production. Research of the existing literature was performed in the Google Scholar, MEDLINE/PubMed, Web of Science, and ScienceDirect databases to identify the currently available publications on the topic of sports mouthguards from January 1951 to August 2023. The terms used were “sports mouthguard”, “mouthguards and orofacial traumas”, and “mouthguards and additive manufacturing”. A total of 920 articles were found, and 39 articles were selected and included in this review. While consensus exists regarding the significance of using sports mouthguards with optimal attributes, there is a need for standardization in the methodology for manufacturing custom-made mouthguards. These can be fashioned with conventional ethylene vinyl acetate (EVA) copolymer reinforcements. Such standardization would ensure uniform stress distribution and guarantee ample protection for oral tissues, allowing for universal reproducibility among dental practitioners. Additive manufacturing stands as an innovative method for fabricating mouthguards, displaying promising benefits. However, the materials and methodologies employed in this workflow still require refinement and characterization for a safe clinical integration. Full article

The purpose of this study was to compare electromyographic (EMG) with mechanomyographic (MMG) recordings during isometric conditions, and during a simulated load-lifting task. Twenty-two males (age: 25.5 ± 5.3 years) first performed maximal voluntary contractions (MVC) and submaximal isometric contractions of upper limb muscles at 25%, 50% and 75% MVC. Participants then executed repetitions of a functional activity simulating a load-lifting task above shoulder level, at 25%, 50% and 75% of their maximum activity (based on MVC). The low-frequency part of the accelerometer signal (<5 Hz) was used to segment the six phases of the motion. EMG and MMG were both recorded during the entire experimental procedure. Root mean square (RMS) and mean power frequency (MPF) were selected as signal extraction features. During isometric contractions, EMG and MMG exhibited similar repeatability scores. They also shared similar RMS vs. force relationship, with RMS increasing to 75% MVC and plateauing to 100%. MPF decreased with increasing force to 75% MVC. In dynamic condition, $RM{S}_{MMG}$ exhibited higher sensitivity to changes in load than $RM{S}_{EMG}$. These results confirm the feasibility of MMG measurements to be used during functional activities outside the laboratory. It opens new perspectives for future applications in sports science, ergonomics and human–machine interface conception. Full article

Wheelchair basketball (WB) is an increasingly popular sport that guarantees numerous health benefits for people with disabilities who regularly practice it, such as an improved quality of life and psychophysical well-being. However, WB is a contact and high-stress sport, which exposes players to frequent overloads and injuries, mainly affecting the upper limbs. Therefore, shoulder pain (SP) is the most common musculoskeletal disorder among WB players, forcing them to suspend or abandon this sport activity. This narrative review aims to summarize all the known literature on this topic and to be a starting point for further research. Firstly, it explores the biomechanical causes that lead to SP and the underlying diseases, among which the most recurrent are rotator cuff tendinopathies. Furthermore, this overview deepens the most effective and specific rehabilitation programs for SP in WB players and it emphasizes the need for further studies to trial new rehabilitative protocols using novel technologies to make them faster and more personalized. In this regard, the general recommendation still remains to perform a combination of exercises such as strengthening, endurance and stretching exercises of various durations and intensities. To conclude, the most important prevention strategies are described, underlining the need for constant sport-specific training led by qualified personnel and suggesting some insights on possible new research aimed at improving wheelchair ergonomics, stressing the importance of a multidisciplinary team fully dedicated to the individual athlete. Full article

Background: The formation of large accelerations on the head and cervical spine during a backward fall is particularly dangerous due to the possibility of affecting the central nervous system (CNS). It may eventually lead to serious injuries and even death. This research aimed to determine the effect of the backward fall technique on the linear acceleration of the head in the transverse plane in students practicing various sports disciplines. Methods: The study involved 41 students divided into two study groups. Group A consisted of 19 martial arts practitioners who, during the study, performed falls using the side aligning of the body technique. Group B consisted of 22 handball players who, during the study, performed falls using the technique performed in a way similar to a gymnastic backward roll. A rotating training simulator (RTS) was used to force falls, and a Wiva^® Science apparatus was used to assess acceleration. Results: The greatest differences in backward fall acceleration were found between the groups during the buttocks’ contact with the ground. Larger changes in head acceleration were noted in group B. Conclusions: The lower changes in head acceleration obtained in physical education students falling with a lateral body position compared to students training handball indicate their lower susceptibility to head, cervical spine, and pelvis injuries when falling backwards as caused by horizontal force. Full article