FOOT-MOVEMENT, LOAD AND INJURY IN VOLLEYBALL

Many human movements are very typical to one sporting activity. Such movements may be a particular way of hittiny a ball (whole body movement) or placing the foot on the ground (one segment movement). Movements are the result of acting forces and as a consequence lead to a loading of joints, tendons and other anatanical structures. Load on the other hand is recognized as a critical factor regarding the occurence of pain and injury (Nigg, Stuessi). So movement, load and injury are related to each other. In running this relation has been pursued for a number of years, in other sports, i.e. volleyball it is almost unknown. The goal of this presentation is twofold: (1) To present a structuring of the game of volleyball in order (2) to establish a relationship between foot-movement, injury and load. Applications are presented using selected examples

l -Carnitine and the recovery from exhaustive endurance exercise: a randomised, double-blind, placebo-controlled trial

We hypothesised that l-carnitine could accelerate recovery from exhaustive exercise since increased blood l-carnitine concentrations elicit a vasodilation in isolated animal vessels as well as in patients with peripheral vascular or coronary artery disease during exercise. Twelve subjects received either 2g l-carnitine or a placebo in a study which was double-blind and crossover in design. Two hours after administration, the subjects performed a constant-load exercise test (CET1) cycling at their individual anaerobic threshold to exhaustion. Three hours later this test was repeated (CET2). After 4-14 days, each subject performed the same cycling tests after having taken the other substance. Exercise times of the 12 subjects were identical with l-carnitine (CET1: 21.3±5.7min; CET2: 21.4±5.3min) and placebo (CET1: 21.9±6.2min; CET2: 20.4±4.8min). Also, heart rate, oxygen consumption, respiratory exchange ratio, and blood lactate concentration were identical. In conclusion, 2g of L-carnitine taken 2h before a first of two constant-load exercise tests had no influence on the second tests performed 3h after the first test compared with placeb

Does a specific MR imaging protocol with a supine-lying subject replicate tarsal kinematics seen during upright standing?

Magnetic resonance (MR) imaging is becoming increasingly important in the study of foot biomechanics. Specific devices have been constructed to load and position the foot while the subject is lying supine in the scanner. The present study examines the efficacy of such a newly developed device in replicating tarsal kinematics seen during the more commonly studied standing loading conditions. The results showed that although knee flexion and the externally applied load were carefully controlled, subtalar and talo-navicular joint rotations while lying during MR imaging and when standing (measured opto-electrically with markers attached to intracortical pins) did not match, nor were they systematically shifted. Thus, the proposed MR protocol cannot replicate tarsal kinematics seen during upright standing. It is concluded that specific foot loading conditions have to be considered when tarsal kinematics are evaluated. Improved replication of tarsal kinematics in different postures should comprehensively consider muscle activity, a fixed hip position, and a well-defined point of load applicatio

Patient doses in CT examinations in Switzerland: implementation of national diagnostic reference levels

Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerlan

External Validation of the Modified 4C Deterioration Model and 4C Mortality Score for COVID-19 Patients in a Swiss Tertiary Hospital

Prognostic models to predict the deterioration and mortality risk in COVID-19 patients are utterly needed to assist in informed decision making. Most of these models, however, are at high risk of bias, model overfitting, and unclear reporting. Here, we aimed to externally validate the modified (urea was omitted) 4C Deterioration Model and 4C Mortality Score in a cohort of Swiss COVID-19 patients and, second, to evaluate whether the inclusion of the neutrophil-to-lymphocyte ratio (NLR) improves the predictive performance of the models. We conducted a retrospective single-centre study with adult patients hospitalized with COVID-19. Both prediction models were updated by including the NLR. Model performance was assessed via the models' discriminatory performance (area under the curve, AUC), calibration (intercept and slope), and their performance overall (Brier score). For the validation of the 4C Deterioration Model and Mortality Score, 546 and 527 patients were included, respectively. In total, 133 (24.4%) patients met the definition of in-hospital deterioration. Discrimination of the 4C Deterioration Model was AUC = 0.78 (95% CI 0.73-0.82). A total of 55 (10.44%) patients died in hospital. Discrimination of the 4C Mortality Score was AUC = 0.85 (95% CI 0.79-0.89). There was no evidence for an incremental value of the NLR. Our data confirm the role of the modified 4C Deterioration Model and Mortality Score as reliable prediction tools for the risk of deterioration and mortality. There was no evidence that the inclusion of NLR improved model performance

Dosimetric comparison of protons vs photons in re-irradiation of intracranial meningioma

Objectives: Re-irradiation of recurrent intracranial meningiomas represents a major challenge due to dose limits of critical structures and the necessity of sufficient dose coverage of the recurrent tumor for local control. The aim of this study was to investigate dosimetric differences between pencil beam scanning protons (PBS) and volumetric modulated arc therapy (VMAT) photons for intracranial re-irradiation of meningiomas. Methods: Nine patients who received an initial dose &gt;50 Gy for intracranial meningioma and who were re-irradiated for recurrence were selected for plan comparison. A volumetric modulated arc therapy photon and a pencil beam scanning proton plan were generated (prescription dose: 15 × 3 Gy) based on the targets used in the re-irradiation treatment. Results: In all cases, where the cumulative dose exceeded 100 or 90 Gy, these high dose volumes were larger for the proton plans. The integral doses were significantly higher in all photon plans (reduction with protons: 48.6%, p &lt; 0.01). In two cases (22.2%), organ at risk (OAR) sparing was superior with the proton plan. In one case (11.1%), the photon plan showed a dosimetric advantage. In the remaining six cases (66.7%), we found no clinically relevant differences in dose to the OARs. Conclusions: The dosimetric results of the accumulated dose for a re-irradiation with protons and with photons were very similar. The photon plans had a steeper dose falloff directly outside the target and were superior in minimizing the high dose volumes. The proton plans achieved a lower integral dose. Clinically relevant OAR sparing was extremely case specific. The optimal treatment modality should be assessed individually. Advances in knowledge: Dose sparing in re-irradiation of intracranial meningiomas with protons or photons is highly case specific and the optimal treatment modality needs to be assessed on an individual basis. </jats:sec

An audit of diagnostic reference levels in interventional cardiology and radiology: are there differences between academic and non-academic centres?

A wide variation in patient exposure has been observed in interventional radiology and cardiology. The purpose of this study was to investigate the patient dose from fluoroscopy-guided procedures performed in non-academic centres when compared with academic centres. Four procedures (coronary angiography, percutaneous coronary intervention, angiography of the lower limbs and percutaneous transluminal angioplasty of the lower limbs) were evaluated. Data on the dose-area product, fluoroscopy time and number of images for 1000 procedures were obtained from 23 non-academic centres and compared with data from 5 academic centres. No differences were found for cardiology procedures performed in non-academic centres versus academic ones. However, significantly lower doses were delivered to patients for procedures of the lower limbs when they were performed in non-academic centres. This may be due to more complex procedures performed in the academic centres. Comparison between the centres showed a great variation in the patient dose for these lower limb procedure

Efectos del entrenamiento de la musculatura respiratoria sobre el rendimiento.

Actualmente, es aceptado por la comunidad científica que el sistema respiratorio puede limitar el ejercicio en personas con enfermedad pulmonar y/o cardiovascular. El objetivo del presente artículo es la revisión de algunos estudios realizados en relación al papel limitante del sistema respiratorio en el rendimiento físico de deportistas. Se realiza una breve descripción técnica de los dispositivos más utilizados para el entrenamiento de la musculatura respiratoria. Finalmente, se presentan los resultados más representativos, obtenidos por diversos investigadores y en distintas poblaciones, relacionados con el entrenamiento de la musculatura respiratoria y sus efectos en el rendimiento físico. Los resultados obtenidos en las distintas investigaciones consultadas sobre el entrenamiento de los músculos respiratorios son dispares, puesto que algunos han mostrado mejoras significativas, mientras otros no han mostrado grandes efectos en el rendimiento. En todos ellos se refleja cómo el sistema respiratorio es un factor limitante del rendimiento físico en deportistas y es preciso plantearse nuevas metodologías, protocolos y planificaciones en el entrenamiento deportivo. El entrenamiento de los músculos respiratorios, tanto mediante dispositivos umbral, de resistencia, o isocapnica, puede provocar mejoras en valores como la presión inspiratoria máxima y mejoras en el rendimiento de algunos deportes; sin embargo, son muy escasos los estudios que han encontrado mejoras en el consumo máximo de oxígeno (VO2max). Las discrepancias entre los estudios analizados pueden estar provocadas por diferencias en las intensidades y duración de los ejercicios utilizados, así como por diferencias en el diseño experimental y el nivel de condición física de los sujetos