IMPACT OF STRENGTHENING EXERCICES ON THE SHOULDER JOINT

Strengthening of shoulder muscles in rehabilitation protocols and sport practice can be achieved by a wide range of different exercises. Very limited objective data is at disposal to emit recommendations for design of a training protocol that aims at minimizing subacromial impingement, stress on the articular cartilages or labrum and excessive tendon elongation of the rotator cuff. The purpose of this study was to evaluate the impact of shoulder rehabilitation exercises on the shoulder joint using motion capture and computer simulations of patient-specific anatomical joint structures

Content Format and Quality of Experience in Virtual Reality

In this paper, we investigate three forms of virtual reality content production and consumption. Namely, 360 stereoscopic video, the combination of a 3D environment with a video billboard for dynamic elements, and a full 3D rendered scene. On one hand, video based techniques facilitate the acquisition of content, but they can limit the experience of the user since the content is captured from a fixed point of view. On the other hand, 3D content allows for point of view translation, but real-time photorealistic rendering is not trivial and comes at high production and processing costs. We also compare the two extremes with an approach that combines dynamic video elements with a 3D virtual environment. We discuss the advantages and disadvantages of these systems, and present the result of a user study with 24 participants. In the study, we evaluated the quality of experience, including presence, simulation sickness and participants' assessment of content quality, of three versions of a cinematic segment with two actors. We found that, in this context, mixing video and 3D content produced the best experience.Comment: 25 page

A motion capture study to measure the feeling of synchrony in romantic couples and in professional musicians

The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronization and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking), the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronization tasks (mirror game), musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms

The Subjective Sensation of Synchrony: an Experimental Study

People performing actions together have a natural tendency to synchronize their behavior. Consistently, people doing a task together build internal representations not only of their actions and goals, but also of the other people performing the task. However, little is known about which are the behavioral mechanisms and the psychological factors affecting the subjective sensation of synchrony, or "connecting" with someone else. In this work, we sought to find which factors induce the subjective sensation of synchrony, combining motion capture data and psychological measures. Our results show that the subjective sensation of synchrony is affected by performance quality together with task category, and time. Psychological factors such as empathy and negative subjective affects also correlate with the subjective sensation of synchrony. However, when people estimate synchrony as seen from a third person perspective, their psychological factors do not affect the accuracy of the estimation. We suggest that to feel this sensation it is necessary to, first, have a good joint performance and, second, to assume the existence of an attention monitoring mechanism that reports that the attention of both participants (self and other) is focused on the task

Shoulder Motion Analysis During Codman Pendulum Exercises

To quantify shoulder motion during Codman pendulum exercises

Analysis of hip range of motion in everyday life ::a pilot study

Patients undergoing total hip arthroplasty are increasingly younger and have a higher demand concerning hip range of motion. To date, there is no clear consensus as to the amplitude of the “normal hip” in everyday life. It is also unknown if the physical examination is an accurate test for setting the values of true hip motion. The purpose of this study was: 1) to precisely determine the necessary hip joint mobility for everyday tasks in young active subjects to be used in computer simulations of prosthetic models in order to evaluate impingement and instability during their practice; 2) to assess the accuracy of passive hip range of motion measurements during clinical examination. A total of 4 healthy volunteers underwent Magnetic Resonance Imaging and 2 motion capture experiments. During experiment 1, routine activities were recorded and applied to prosthetic hip 3D models including nine cup configurations. During experiment 2, a clinical examination was performed, while the motion of the subjects was simultaneously captured. Important hip flexion (mean range 95°-107°) was measured during daily activities that could expose the prosthetic hip to impingement and instability. The error made by the clinicians during physical examination varied in the range of ±10°, except for flexion and abduction where the error was higher. This study provides useful information for the surgical planning to help restore hip mobility and stability, when dealing with young active patients. The physical examination seems to be a precise method for determining passive hip motion, if care is taken to stabilise the pelvis during hip flexion and abduction

MyHip: supporting planning and surgical guidance for a better total hip arthroplasty: A pilot study

Purpose: Total hip arthroplasty (THA) aims to restore patient mobility by providing a pain-free and stable artificial joint. A successful THA depends on the planning and its execution during surgery. Both tasks rely on the experience of the surgeon to understand the complex biomechanical behavior of the hip. We investigate the hypothesis that a computer-assisted solution for THA effectively supports the preparation and execution of the planning. Methods: We devised MyHip as a computer-assisted framework for THA. The framework provides pre-operative planning based on medical imaging and optical motion capture to optimally select and position the implant. The planning considers the morphology and range of motion of the patient's hip to reduce the risk of impingements and joint instability. The framework also provides intra-operative support based on patient-specific surgical guides. We performed a post-operative analysis on three patients who underwent THA. Based on post-operative radiological images, we reconstructed a patient-specific model of the prosthetic hip to compare planned and effective positioning of the implants. Results: When the guides were used, we measured non-significant variations of planned executions such as bone cutting. Moreover, patients' hip motions were acquired and used in a dynamic simulation of the prosthetic hip. Conflicts prone to implant failure, such as impingements or subluxations, were not detected. Conclusions: The results show that MyHip provides a promising computer assistance for THA. The results of the dynamic simulation highlighted the quality of the surgery and especially of its planning. The planning was properly executed since non-significant variations were detected during the radiological analysis

MyHip ::supporting planning and surgical guidance for a better total hip arthroplasty

Purpose : Total hip arthroplasty (THA) aims to restore patient mobility by providing a pain-free and stable artificial joint. A successful THA depends on the planning and its execution during surgery. Both tasks rely on the experience of the surgeon to understand the complex biomechanical behavior of the hip. We investigate the hypothesis that a computer-assisted solution for THA effectively supports the preparation and execution of the planning. Methods : We devised MyHip as a computer-assisted framework for THA. The framework provides pre-operative planning based on medical imaging and optical motion capture to optimally select and position the implant. The planning considers the morphology and range of motion of the patient’s hip to reduce the risk of impingements and joint instability. The framework also provides intra-operative support based on patient-specific surgical guides. We performed a post-operative analysis on three patients who underwent THA. Based on post-operative radiological images, we reconstructed a patient-specific model of the prosthetic hip to compare planned and effective positioning of the implants. Results : When the guides were used, we measured non-significant variations of planned executions such as bone cutting. Moreover, patients’ hip motions were acquired and used in a dynamic simulation of the prosthetic hip. Conflicts prone to implant failure, such as impingements or subluxations, were not detected. Conclusions : The results show that MyHip provides a promising computer assistance for THA. The results of the dynamic simulation highlighted the quality of the surgery and especially of its planning. The planning was properly executed since non-significant variations were detected during the radiological analysis