Open Access

Rationale: Three-dimensional (3D) motion analysis has proved helpful in the diagnosis of different musculoskeletal syndromes and identifying injurious movement patterns in high string players. Furthermore, an optoelectronic 3D motion capture system allows an accurate and objective assessment of upper body posture and motion during violin and viola performance. However, no reference upper body model of high string players has been proposed as yet. Moreover, a more physiological shoulder model that separates the joints of the shoulder complex has not been reported. Especially in view of given the role of the scapula in the normal movement of the humerus, it cannot be disregarded when evaluating musculoskeletal strain in the shoulder. The International Society of Biomechanics recommends definitions of joint coordinate systems for the report of upper body joint motion using anatomical landmarks as reference for the placement of surface markers. Using markers on the skin for some of the proposed locations is, however, inappropriate when an instrument is being played. There are skin movement artifacts, e. g. caused by the movement of the scapula underneath the skin, whereas some markers interfere with the instrument on the shoulder or might be occluded by the bowing arm in motion. Purpose: The aim of this study was to develop a marker-based method for quantifying 3D upper body kinematics of high string players and to demonstrate its clinical feasibility in violin and viola performance. The method is intended to provide an objective evaluation of high string players’ motor strategies, especially in the shoulder complex, while minimizing skin movement artifacts, marker occlusions and limitations in instrument placement. Methods: A custom marker set was developed consisting of thirty-one single markers to define the anatomical coordinate systems of sixteen upper body segments including the pelvis, thorax, spine and head, as well as both scapulae, upper arms, forearms and hands. Twenty-one of these markers as well as two pre-built and four custom-made rigid marker clusters were used for tracking the segment motions. Twelve professional violinists without history of musculoskeletal or neurological problems were recruited for assessing the clinical feasibility of the method. They were asked to perform a single sequence of two consecutive musical notes on each of two adjacent strings (G- and D-string) in real time, played at 50 bpm with tempo audibly regulated by a metronome, and using a standardized violin and bow. The participants played up- and down-bow alternately using the whole length of the bow. A custom biomechanical model was applied to the motion capture data and the rotation angles of fifteen joints were calculated. The location of each glenohumeral joint rotation center was computed by upper arm movements with respect to the scapula based on a functional method. For a description of the motion patterns, minimum, maximum and range of angular motion were averaged across participants for each string and rotation. Inter-subject variability was assessed by calculating the standard deviation (SD) at each sample of the angle-time series between participants for each rotation and for both strings. Then SD was averaged over sequences for each rotation and string. For comparing mean rotation angles between strings over time, random effect models were used. Results: The highest range of motion was observed in the right elbow flexion and right wrist flexion/extension. Also, high ranges of motion (> 10°) were found in all right glenohumeral rotations and right wrist deviation and pronation/supination. In conclusion, lumbar and thoracic spine, thorax, neck, and left upper limb were quite static, while large motion occurred in the right upper limb during up and down bowing. Most rotation angles showed a reasonable inter-subject variability except for left and right glenohumeral plane of elevation as well as left glenohumeral internal/external rotation, and left and right wrist pronation/supination (> 10°). Significant differences in the rotation angles between G- and D-string bowing were detected especially in the left wrist and right shoulder joints. Conclusions: This is the first study that used quantitative 3D analysis to explore the upper body kinematics of high string players during performance, providing a detailed view of the motor control in the shoulder as well as in the lumbar and thoracic spine. The biggest advantage over previously published methods is the more physiological shoulder and spine models while providing a simple application. The method was found to give consistent motion patterns across participants and to be sensitive to differences between adjacent strings. Although the method appears to be valid, more rigorous validation is necessary. Since there is no gold standard with which we could compare results, we were only able to assess the clinical feasibility. We believe that our method represents a good compromise between accuracy and practicability for clinical application. Due to the inclusion of multi-segmented shoulder and spine models, it will improve understanding of the motor strategies adopted by high string players and may contribute to injury prevention, diagnosis and treatment.

Rationale: Dance as an intense kind of performance is associated with high loads on the musculoskeletal system. In particular, the lower limb is exposed to these high loads, which is reported by a high prevalence. Most dancers are affected by injuries during their careers, most in the lower limb. Typical risk factors for dancers include the compensatory turnout, hypermobility, and core stability. The correlation between these factors and lower limb injuries is not fully understood. Purpose: The aim of this study was to evaluate the correlation between lower limb injuries and the risk factors compensated turnout, hypermobility and core stability. Based on these results, hypotheses can be generated for further studies. Methods: This explorative pilot study was conducted at Osnabrück University of Applied Sciences. All eligible participants were scheduled for a single research appointment if they fulfilled the inclusion criteria of dance experience (ballet, modern, contemporary or jazz) at least one year with dance lessons of at least 5 hours per week. Parameters for the correlation analysis were (1) core stability, measured by the motor control tests battery proposed by Luomajoki, (2) hypermobility, measured by the Beighton Score (3) compensated turnout, measured by the difference between functional turnout and external rotation of both hips, (4) dance hours per week, (5) dance experience in years, (6) professional dance experience in years and (7) dance style (ballet, modern, contemporary, jazz). These parameters were correlated with the numbers of lower limb injuries. Significance level was set at 90% because of the explorative character of the study with the purpose to generate hypotheses. Results: Sixteen female dancers with different levels of dance experience (mean 11.3 years) and dance lessons per week (mean 17.6 hours) fulfilled the inclusion criteria and participated in this study. Significant correlations with the numbers of lower limb injuries were found at core stability (rs=0.489, p=0.034, medium effect), dance hours per week (rs=0.459, p=0.048, medium effect) and professional dance experience in years (rs=0.396, p=0.093, medium effect). Two dance styles (modern dance: rs=0.388, p=0.101 and contemporary dance: rs=0.385, p=0.104) were close to the significance level. Conclusions: These results show correlations between core stability, dance hours per week, professional dance experience in years and lower limb injuries in dancers. Due to the limitations of a small and heterogeneous sample size as well as the medium effects, these results should be interpreted with caution, but may provide a basis for further research to this topic in the field of dance research and can be helpful in generating research hypotheses.

Climate change is the biggest social challenge facing the globalised world. The aim of this paper is to investigate the requirements for governance structures in regional sustainability programmes against climate change. The study is an explorative case study. It is based on a literature review and expert interviews. It also involves the participatory observation of working groups meetings, and a design thinking workshop. In spite of their enormous importance, little is known about the institutional conditions of the regional governance of climate change projects in Germany. For this reason, the research project focuses on the important aspect of networking and governance structures. Consequently, the investigation will contribute to answering the question of which institutional framework conditions can raise the likelihood of climate change projects having a sustainable effect. The outcomes of the application This research has not only practical implications for the single case. The exploration of the critical factors of success also offers other regions important food for thought in shaping their governance structures. In particular, the design thinking process and the business network in the District of Steinfurt offer valuable points of reference.

The usage of high-level synthesis (HLS) tools for FPGAs has increased significantly over the last years since they matured and allow software programmers to take advantage of reconfigurable hardware technology. Most HLS tools employ methods to optimize for loops, e. g. by unrolling or pipelining them. But there is hardly any work on the optimization of while loops. This comes at no surprise since most while loops have loop-carried dependences involving the loop condition which result in large recurrence cycles in the dataflow graphs. Therefore typical while loops cannot be parallelized or pipelined. We propose a novel transformation which allows to optimize while loops nested within a for loop. By interchanging the two loops, it is possible to pipeline (and thereby parallelize) the inner loop, resulting in a reduced execution time. We present two case studies on different hardware platforms and show the speedup factors - compared to a host processor and to an unoptimized hardware implementation - achieved by our while loop optimization method.

This paper introduces and empirically illustrates a pedagogical approach to teaching Public Relations (PR) in higher education. The approach is based on the Communities of Practice theory (Wenger, 1998). Based on this theory and for the purposes of this paper, learning is perceived as (1) a participation in a practice of (2) a social community and (3) the understanding of this practice. The pedagogical approach to teaching PR entails the facilitation of these three elements. The approach is illustrated through a case study. The authors conducted an international undergraduate course to teach students how to conduct a social media campaign to raise engagement for social issues. Twenty students from Netherlands and Germany enrolled. The paper offers an integrated understanding of theory and practice (see Wenger, 1998, p. 48). It contrasts many current approaches in PR education, which tend to differentiate between PR theory and practice. PR educators are encouraged to facilitate an equal negotiation between theory and practice and to enable students to match whatever is theorised with practice and whatever is practiced with theory.