Title: The effect of shoulder girdle stabilization exercises on muscle activity during direct impact in rugby players with sub-acromial impingement syndrome Objectives: Comparison of muscle activity during direct impact while performing the rugby tackle to tackle bag and to player using electromyographic amplitude analysis before and after intervention programme for players with subacromial impingement syndrome (SIS). Application of intervention programme consisting stabilization excercises for shoulder complex and activation of deep stabilization muscles of the spine. Methods: Theoretical part contains topics about shoulder girdle, rugby and rugby injuries, mainly subacromial impingement syndrome. Mentioned issues are included into the thesis due to the research of current literature from international sources and studies. Practical part regards the aplication of three-months long intervention programme for eight players at junior national level with diagnosis of SIS, when pre-testing a post-testing is realized by clinical tests and EMG measurement. Assessment of enter and control examination is realized with analysis of variance ANOVA. Results: Intervention programme was sufficient for changes in EMG amplitude for two muscle groups in rugby players with SIS. Hypothesis comparing the EMG measure...

TitleVVVVVVV VVVVV Objectives:VVV VVVVVVVVV VVVVVV Methods: VVVVVVVV VVVVVVVVV VVVVVVVVV VVVVVVVVV VVVVVVVVV VVVVVVVVV VV Results VVVVVVVVV VVVVVVVVV VVVVVVVVV V Key words Comparative analysis of chosen muscles in locomotion through shoulder girdle The aim of this study is to describe and to compare the canoe forward stroke with selected exercises performer during indoor training The research was conducted in an intentionally chosen sample of ten probands with high level of performance in whitewater slalom. We watched activity of ten selected muscles during canoe forward stroke, on simulator, diagonal pull, stretch of arms with elastic resistance, dumbbell pulls and pull ups by surface electromyography. Study evaluates intraindividual and subsequently interindividual the size of the muscle activation considering reference movement, forward stroke on flat water. The results proved similarities of the forward stroke and on simulator in terms of average muscle activation. M. latissimus dorsi shows higher activation during canoe forward stroke, on simulator, stretch of arms with elastic resistance, dumbbell pulls compared with other tested exercices. locomotion through the shoulder girdle, shot, canoeing, paddling, electromyography, muscular activity

Title Objectives: Methods: Results Key words Comparative analysis of chosen muscles in locomotion through shoulder girdle The aim of this study is to describe and to compare selected exercises performer during indoor training toward the canoe forward stroke. The research was conducted in an intentionally chosen sample of ten probands with high level of performance in whitewater slalom. We watched activity of ten selected muscles during canoe forward stroke, on simulator, diagonal pull, stretch of arms with elastic resistance, dumbbell pulls and pull ups by surface electromyography. Study evaluates intraindividual and subsequently interindividual the size of the muscle activation considering reference movement, forward stroke on flat water. The results proved similarities of the forward stroke and on simulator in terms of average muscle activation. M. latissimus dorsi shows higher activation during canoe forward stroke, on simulator, stretch of arms with elastic resistance, dumbbell pulls compared with other tested exercices. locomotion through the shoulder girdle, shot, canoeing, paddling, electromyography, muscular activity

Magister Scientiae Dentium - MSc(Dent) / The treatment objectives in the restoration of an endodontically treated tooth are maximum retention of post and core and to create a design in which the tooth is preserved when the restoration fails. The ferrule effect in root treated teeth requiring cast post and core has been studied extensively and has been shown to greatly improve fracture resistance (Gluskin et al 1995, Libman & Nicholls, 1995. Hemmings et al, 1991. Barkhordar et al, 1989. Rosen & Partida-Rivera, 1986). Studies have also shown that in the case of cast post and core, the longer the ferrule, the greater the fracture resistance (Libman and Nicholls, 1995). The use of the new bonding agents, composite resin cements and core materials, have led to a more conservative approach to post and core restorations. However few studies have considered the effect of different ferrule designs on prefabricated post and composite core systems (Volwiler et al 1989, Al Hazaimeh and Gutteridge 2001). There is little information as to whether the ferrule is of additional value in providing reinforcement in these restorations. This study investigated the effects of different ferrule designs on the fracture resistance of teeth incorporating prefabricated posts and composite cores. In addition teeth restored with a composite core but with no prefabricated post were included in the study to assess the necessity of a post in the restoration of endodonticallytreated teeth. Sixty extracted maxillary incisors (centrals and laterals) and carunes were randomly assigned into three groups and restored. Two groups had a prefabricated post and composite core with varying ferrule designs. A third group had a core with composite packed into the root canal but no post. All teeth were restored with cast crowns to simulate the clinical situation. A Zwick universal testing machine was used to apply compressive loads progressively on the restored teeth until failure occurred as a result of either root, tooth or post fracture. Failure loads, modes of fracture, post and core systems and tooth preparation were recorded and statistically analysed. The results showed no significant difference in the amount of force needed to break the teeth in the different groups irrespective of whether the teeth had a ferrule or not. They also showed no significant difference in the amount of force needed to break the teeth in the different groups irrespective of whether the teeth had a post or not.

Shoulder surfing, also known as visual hacking, is the activity of obtaining information from or about others by observing visual content of displays that actually should be kept secret, such as PINs, passwords, or private text messages. Approaches that address shoulder surfing on mobile devices mainly focus on ways to recognize observers or to complicate visual presentations for them from the system's perspective. However, users also have developed their own strategies to keep their input secret. With this work, we contribute an investigation of strategies to prevent shoulder surfing from the users' perspective. We performed a user study and observed 32 participants while interacting with smartphones using different kinds of eyes-free device-based interaction techniques. We identified several strategies that users had to prevent shoulder surfing. These strategies help us to develop effective ways to design useful interactions that overcome shoulder surfing issues.

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CrossFit® has gained popularity as a functional training method that caters to individuals with varying levels of fitness, including those with little to no athletic background. Regardless, shoulders represent the highest injury rate in this sport, most frequently associated with pull-up variations. Therefore, ensuring safety during these movements is crucial. This thesis utilized optical motion tracking, force sensors, and Electromyography to measure nine experienced non-professional CrossFit® athletes performing three pull-up techniques used in CrossFit® (strict, kipping, and butterfly). Data were used in musculoskeletal modeling to assess and compare kinematics, kinetics, and muscle activations. Findings were then associated with common injury factors observed in overhead athletes. The novel dataset generated in this study demonstrated excellent repeatability and revealed significant differences between the techniques for most kinematic and kinetic variables, while variations in muscle activations were less systematic. Results indicated shoulder joint angles linked to impingement risk, with the kipping pull-up displaying more prominent risk factors. The butterfly pull-up exhibited extreme angular velocities and negative joint powers; however, direct associations with injuries could not be established. Notably, shoulder joint moments were high in all three techniques, suggesting significant muscle stresses. These results underscore the importance of individualized training load management to mitigate the risk of overuse injuries. Furthermore, the evidence presented in this study supports the importance of maintaining proper mechanics and developing strength before attempting kipping and butterfly pull-ups. The high joint moments, combined with severe positions and velocities observed during these techniques, highlight the necessity of prioritizing foundational strength and technique to minimize injury risks. / CrossFit® har blivit populärt som en funktionell träningsmetod som lockar individueller med olika fitnessnivåer, även de utan tidigare idrottserfarenhet. Trots detta utgör axelskada den högsta skadefrekvensen inom denna sport och är oftast förknippad med räckhäv varianter. Därför är det avgörande att garantera säkra övningarna. Denna studie använde optisk rörelsespårning, kraftsensorer och elektromyografi för att mäta nio tränade icke-professionella CrossFit® atleter utförande av tre olika räckhäv tekniker som används inom CrossFit® (strikta, kipping och butterfly). Data användes för muskuloskeletala modeller för att uppskatta och jämföra kinematik, kinetik och muskelaktivering. Resultaten förknippades med till vanliga skadefaktorer som observeras hos overhead-idrottare. Det nya datasetet som genererades i denna studie visade utmärkt repeterbarhet och avslöjade signifikanta skillnader mellan teknikerna för de flesta kinematiska och kinetiska variablerna, medan variationer i muskelaktiveringar var mindre systematiska. Resultaten visade på axelledens vinklar som var kopplade till inklämningsrisk, där kipping pull-up uppvisade mer framträdande riskfaktorer. Butterfly pull-up uppvisade extrema vinkelhastigheter och negativa ledkrafter; men direkta samband med skador har inte upprättats. Det är anmärkningsvärt att axelledsmomenten var höga i alla tre tekniker, vilket tyder på betydande muskelspänningar. Dessa resultat understryker vikten av individualiserad hantering av träningsbelastning för att minska risken för överbelastningsskador. Dessutom stöder de bevis som presenteras i den här studien vikten av att behålla rätt mekanik och utveckla styrka innan man försöker göra kipping och butterfly pull-ups. De höga ledmomenten i kombination med svåra positioner och hastigheter som observerades under dessa tekniker lyfter fram behovet av att prioritera grundläggande styrka och teknik för att minimera risk för skador.

The shoulder is one of the most complex joints in the body. It has a large range of motion and has active, as well as passive, components to its stabilization. Many injuries occur every year due to overexertion and strain on the shoulder. Musculoskeletal models can be used as a proactive ergonomics tool for shoulder specific job task design, and to help prevent these injuries before they occur. The purpose of this thesis was to critically evaluate the performance of four optimization criteria (sum of squared activation, sum of cubed activation, sum of quartic activation, and entropy assisted) using the open source modeling platform OpenSIM. Experimental torque, kinematic, and EMG data were collected using ten participants for a variety of dynamic arm movements, and static arm postures, in different planes of action. The kinematic and torque data were processed and used as inputs to OpenSIM to calculate predicted muscle activations and joint reaction forces. Experimental EMG was cross correlated with the predicted muscle activity of 8 muscles, and RMSD was calculated between experimental and predicted muscle activity for evaluation. A co-contraction index was also used to assess the model’s ability to predict co-activation between muscle pairs. Overall, the sum of cubed activation and sum of quartic activation model predictions explained significantly more variance (38 ±2.5%, p<0.01) than the sum of squares and entropy models, when compared with experimental EMG. In conclusion, the type of optimization criterion chosen had an effect on the accuracy of the model predictions. Future research, in the development of optimization criterions for the shoulder, will create better model predictions of muscle forces and joint reaction forces, enabling musculoskeletal models to be more useful as a tool to the clinical and ergonomic populations. / Thesis / Master of Science (MSc) / The shoulder is one of the most complex joints in the body. It has a large range of motion and has muscles and ligaments to support the stability of the complex. Many injuries occur every year due to overexertion and strain on the shoulder. Proactively modelling can help reduce these injuries by evaluating a job's likelihood to injure a worker before the worker does the job. The purpose of this thesis was to evaluate the performance of several different shoulder models. Experimental torque, kinematic, and EMG data were collected using ten participants for a variety of dynamic arm movements, and static arm postures, in different planes of action. The kinematic and torque data were used by the model to predict muscle activations and joint reaction forces. Experimental EMG was cross correlated with the predicted muscle activity of 8 muscles, and RMSD was calculated between experimental and predicted muscle activity for evaluation. A co-contraction index was also used to assess the model’s ability to predict co-activation between muscle pairs. Overall, the sum of cubed activation and sum of quartic activation model predictions explained significantly more variance (38 ±2.5%, p<0.01) than the sum of squares and entropy models, when compared with experimental EMG. In conclusion, the type of model chosen had an effect on the accuracy of the model predictions. Future research, in the development of optimization criterions for shoulder models, will create better model predictions of muscle forces and joint reaction forces, enabling musculoskeletal models to be more useful as a tool to the clinical and ergonomic populations.

Reverse Total shoulder arthroplasty (RTSA) is an effective treatment and a surgical alternative approach to conventional total shoulder arthroplasty for patients with severe rotator cuff tears and glenoid erosion. To help optimize RTSA design, it is necessary to gain insight into the geometry of glenoid erosions and consider their unique morphology across the entire bone. One of the most powerful tools to systematically quantify and visualize the variation of bone geometry throughout a population is Statistical Shape Modeling (SSM); this method can assess the variation in the full shape of a bone, rather than of discrete anatomical features, which is very useful in identifying abnormalities, planning surgeries, and improving implant designs. Recently, many scapula SSMs have been presented in the literature; however, each has been created using normal and healthy bones. Therefore, creation of a scapula SSM derived exclusively from patients exhibiting complex glenoid bone erosions is critical and significantly challenging. In addition, several studies have quantified scapular bone properties in patients with complex glenoid erosion. However, because of their discrete nature these analyses cannot be used as the basis for Finite Element Modeling (FEM). Thus, a need exists to systematically quantify the variation of bone properties in a glenoid erosion patient population using a method that captures variation across the entire bone. This can be achieved using Statistical Intensity Modeling (SIM), which can then generate scapula FEMs with realistic bone properties for evaluation of orthopaedic implants. Using an SIM enables researchers to generate models with bone properties that represent a specific, known portion of the population variation, which makes the findings more generalizable. Accordingly, the main purpose of this research is to develop an SSM and SIM to mathematically quantifying the variation of bone geometries in a systematic manner for the complex geometry of scapulae with severe glenoid erosion and to determine the main modes of variation in bone property distribution, which could be used for future FEM studies, respectively. To draw meaningful statistical conclusions from the dataset, we need to compare and relate corresponding parts of the scapula. To achieve this correspondence, 3D triangulated mesh models of 61 scapulae were created from pre-operative CT scans from patients who were treated with RTSA and then a Non-Rigid (NR) registration method was used to morph one Atlas point cloud to the shapes of all other bones. However, the more complex the shape, the more difficult it is to maintain good correspondence. To overcome this challenge, we have adapted and optimized a NR-Iterative Closest Point (ICP) method and applied that on 61 eroded scapulae which results in each bone shape having identical mesh structure (i.e., same number and anatomical location of points). To assess the quality of our proposed algorithm, the resulting correspondence error was evaluated by comparing the positions of ground truth points and the corresponding point locations produced by the algorithm. The average correspondence error of all anatomical landmarks across the two observers was 2.74 mm with inter and intra-observer reliability of ±0.31 and ±0.06 mm. Moreover, the Root-Mean-Square (RMS) and Hausdorff errors of geometric registration between the original and the deformed models were calculated 0.25±0.04 mm and 0.76±0.14 mm, respectively. After registration, Principal Component Analysis (PCA) is applied to the deformed models as a group to describe independent modes of variation in the dataset. The robustness of the SSM is also evaluated using three standard metrics: compactness, generality, and specificity. Regarding compactness, the first 9 principal modes of variations accounted for 95% variability, while the model’s generality error and the calculated specificity over 10,000 instances were found to be 2.6 mm and 2.99 mm, respectively. The SIM results showed that the first mode of variation accounts for overall changes in intensity across the entire bone, while the second mode represented localized changes in the glenoid vault bone quality. The third mode showed changes in intensity at the posterior and inferior glenoid rim associated with posteroinferior glenoid rim erosion which suggests avoiding fixation in this region and preferentially placing screws in the anterosuperior region of the glenoid to improve implant fixation. / Graduate