SOFT TISSUE ARTEFACTS CAUSE AN UNDERESTIMATION IN KNEE FLEXION ANGLE IN SKINMARKER BASED SQUAT SIMULATIONS

Simulated muscle forces provide crucial knowledge for rehabilitation and training exercise design. To accurately simulate the internal loading conditions, input kinematics of the skeletal structures without soft tissue artefact (STA) are required. The aim of this study was to evaluate the ability of two numerical approaches to reduce STA for squat kinematics. Squat repetitions of 6 elderly subjects were examined using skin markers and video-fluoroscopy. Kinematic analysis was performed with a segmental and musculoskeletal simulation approach and compared to fluoroscopic data. The averaged RMS errors relative to the maximum knee range of motion were 8.8%, 32% and 49% for flexion/extension, ab-/adduction, and internal/external rotation, respectively. Skin marker based underestimation of the flexion angle could be corrected with a linear factor of 1.15

Esports: The chess of the 21st century

© 2019 Pluss, Bennett, Novak, Panchuk, Coutts and Fransen. For many decades, researchers have explored the true potential of human achievement. The expertise field has come a long way since the early works of de Groot (1965) and Chase and Simon (1973). Since then, this inquiry has expanded into the areas of music, science, technology, sport, academia, and art. Despite the vast amount of research to date, the capability of study methodologies to truly capture the nature of expertise remains questionable. Some considerations include (i) the individual bias in the retrospective recall of developmental activities, (ii) the ability to develop ecologically valid tasks, and (iii) difficulties capturing the influence of confounding factors on expertise. This article proposes that expertise research in electronic sports (esports) presents an opportunity to overcome some of these considerations. Esports involves individuals or teams of players that compete in video game competitions via human-computer interaction. Advantages of applying the expert performance approach in esports include (i) developmental activities are objectively tracked and automatically logged online, (ii) the constraints of representative tasks correspond with the real-world environment of esports performance, and (iii) expertise has emerged without the influence of guided systematic training environments. Therefore, this article argues that esports research provides an ideal opportunity to further advance research on the development and assessment of human expertise

Efficacy of AZM therapy in patients with gingival overgrowth induced by Cyclosporine A: a systematic review

<p>Abstract</p> <p>Background</p> <p>In daily clinical practice of a dental department it's common to find gingival overgrowth (GO) in periodontal patients under treatment with Cyclosporine A (CsA). The pathogenesis of GO and the mechanism of action of Azithromycin (AZM) are unclear. A systematic review was conducted in order to evaluate the efficacy of Azithromycin in patients with gingival overgrowth induced by assumption of Cyclosporine A.</p> <p>Methods</p> <p>A bibliographic search was performed using the online databases MEDLINE, EMBASE and Cochrane Central of Register Controlled Trials (CENTRAL) in the time period between 1966 and September 2008.</p> <p>Results</p> <p>The literature search retrieved 24 articles; only 5 were Randomised Controlled Trials (RCTs), published in English, fulfilled the inclusion criteria. A great heterogeneity between proposed treatments and outcomes was found, and this did not allow to conduct a quantitative meta-analysis. The systematic review revealed that a 5-day course of Azithromycin with Scaling and Root Planing reduces the degree of gingival overgrowth, while a 7-day course of metronidazole is only effective on concomitant bacterial over-infection.</p> <p>Conclusion</p> <p>Few RCTs on the efficacy of systemic antibiotic therapy in case of GO were found in the literature review. A systemic antibiotic therapy without plaque and calculus removal is not able to reduce gingival overgrowth. The great heterogeneity of diagnostic data and outcomes is due to the lack of precise diagnostic methods and protocols about GO. Future studies need to improve both diagnostic methods and tools and adequate classification aimed to determine a correct prognosis and an appropriate therapy for gingival overgrowth.</p

Forecasting the development of explosive leg power in youth soccer players

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. Purpose: Monitoring athletic development in youth soccer can help sporting professionals monitor athletic development and evaluate the effectiveness of training interventions. However, long-term follow up in talent development programmes in youth soccer is complicated. Therefore, the aim of this study was to forecast the developmental trajectories of explosive leg power in youth soccer players. Methods: Mixed effects regression models were used to forecast explosive leg power (countermovement (CMJ) and standing broad jump (SBJ)) in a longitudinal sample of 2201 youth soccer players from two high level Belgian acedemies and the Belgian National teams. Players were aged between 6 and 20 years (mean age = 13.04 ± 3.18 y) and were subdivided into three age cohorts (6–10, 11–15, and 16–20 y) for CMJ and two age cohorts (6–16, and 17–20 y) for SBJ. Results: This study was able to accurately forecast explosive leg power using different regression equations in each age cohort. Conclusions: Researchers, coaches, and sporting professionals can use these methods to either predict future explosive leg power from current performance measures, monitor the development of explosive leg power, or assess the effectiveness of training interactions aimed at altering predicted developmental trajectories

Power profiles of competitive and noncompetitive mountain bikers

The performance of Olympic distance cross-country mountain bikers (XCO-MTB) is affected by constraints such as erosion of track surfaces and mass start congestion which can affect race results. Standardized laboratory assessments quantify interseasonal and intraseasonal cycling potential through the assessment of multiple physiological capacities. Therefore, this study examined whether the power profile assessment (PPA) could discriminate between competitive XCO-MTB and noncompetitive mountain bikers (NC-MTB). Second, it aimed to report normative power profile data for competitive XCO-MTB cyclists. Twenty-nine male participants were recruited across groups of XCO-MTB (n = 14) and NC-MTB (n = 15) mountain bikers. Each cyclist completed a PPA that consisted of increasing duration maximal efforts (6, 15, 30, 60, 240, and 600 seconds) that were interspersed by longer rest periods (174, 225, 330, 480, and 600 seconds) between efforts. Normative power outputs were established for XCO-MTB cyclists ranging between 13.8 ± 1.5 W·kg -1 (5-second effort) and 4.1 ± 0.6 W·kg -1 (600-second effort). No differences in absolute peak power or cadence were identified between groups across any effort length (p > 0.05). However, the XCO-MTB cyclists produced greater mean power outputs relative to body mass than the NC-MTB during the 60-second (6.9 ± 0.8 vs 6.4 ± 0.6 W·kg -1 ; p = 0.002), 240-second (4.7 ± 0.7 vs. 3.8 ± 0.4 W·kg -1 ; p < 0.001), and 600-second (4.1 ± 0.6 vs. 3.4 ± 0.3 W·kg -1 ; p < 0.001) efforts. The PPA is a useful discriminative assessment tool for XCO-MTB and highlights the importance of aerobic power for XCO-MTB performanc