Injury rate,mechanism, and risk factors of hamstring strain injuries in sports: A review of the literature

Hamstring strains are one of most common sports injuries. The purpose of this literature review is to summarize studies on hamstring strain injury rate, mechanism, and risk factors in the last several decades with a focus on the prevention and rehabilitation of this injury. Hamstring injury commonly occurs in sporting events in which high speed sprinting and kicking are frequently performed, such as Australian football, English rugby, American football, and soccer. Basic science studies have demonstrated that a muscle strain injury occurs due to excessive strain in eccentric contraction instead of force, and that elongation speed and duration of activation before eccentric contraction affect the severity of the injury. Hamstring strain injury is likely to occur during the late swing phase and late stance phase of sprint running. Shortened optimum muscle length, lack of muscle flexibility, strength imbalance, insufficient warm-up, fatigue, lower back injury, poor lumbar posture, and increased muscle neural tension have been identified as modifiable risk factors while muscle compositions, age, race, and previous injuries are non-modifiable risk factors. The theoretical basis of some of these risk factors, however, is lacking, and the results of clinical studies on these risk factors are inconsistent. Future studies are needed to establish the cause-and-effect relationships between those proposed risk factors and the injury.     

The effects of psoas major and lumbar lordosis on hip flexion and sprint performance

In this study, we analyzed the correlations between hip flexion power; sprint performance, lumbar lordosis (LL) and the cross-sectional area (CSA) of the psoas muscle (PM). Ten young adults performed two sprint tests and isokinetic tests to determine hip flexion power. Magnetic resonance imaging was used to determine LL and PM CSA. There were correlations between hip flexion power, sprint performance, and PM CSA, but LL showed no correlation with any parameter The impact of hip flexion power and LL on sprint stride pattern efficiency was considered. Hip flexion might not have a simple role in the passive knee replacement of the stride pattern; instead, it may be an active parameter. Other investigations are needed to determine the influence of pelvic architecture on sprint performance.     

Virtual Reality in Anatomy: A Pilot Study Evaluating Different Delivery Modalities

Technologies such as virtual reality are used in higher education to develop virtual learning resources (VLRs). These VLRs can be delivered in multiple modalities, from truly immersive involving wearable devices to less immersive modalities such as desktop. However, research investigating perceptions of VLRs in anatomy has mainly focused on a single delivery modality and a limited-demographic participant cohort, warranting a comparison of different modalities and a consideration of different cohorts. This pilot study aimed to compare perceptions of highly immersive and less immersive VLR deliveries among anatomy students and tutors and evaluate the impact of prior university experience on students' perceptions of VLRs. A skull anatomy VLR was developed using the Unity^® gaming platform and participants were voluntarily recruited to assess highly immersive stereoscopic and less immersive desktop deliveries of the VLR. A validated survey tool was used to gather perceptions of both deliveries. Most participants agreed that both VLR deliveries were interesting and engaging and provided an immersive experience. Anatomy students perceived the stereoscopic delivery to be significantly more useful for understanding (P = 0.013), while anatomy tutors perceived the desktop delivery as more useful. A degree of physical discomfort and disorientation was reported by some participants for both deliveries, although to a greater extent for the stereoscopic delivery. The stereoscopic delivery was also found to be more mentally taxing than desktop delivery. These results suggest that desktop VLR delivery may minimize the risk of discomfort and disorientation associated with more immersive modalities while still providing a valuable learning experience.     

Foundational aspects of classroom relations: associations between teachers’ immediacy behaviours,classroom democracy,class identification and learning

This study focused on foundational aspects of classroom relations. Specifically, relationships between teachers’ immediacy (interpersonal) behaviours, classroom democracy, identification and learning were considered. Previous work suggests that these variables can be used as a foundation to shape classroom climate, culture and learning outcomes and, by extension, assist educational institutions to achieve their civic mission. This study examined classroom democracy and class identification as variables that mediate the relationship between immediacy behaviours and learning using data collected from 529 students in six institutions of higher learning in Rwanda. Structural equation modeling revealed that classroom democracy mediates the relationship between immediacy behaviours and that classroom democracy and class identification covary substantially. The significant relationships in the final structural model suggest that immediate teachers are likely to have a positive influence on perceptions of classroom democracy, class identification and learning. Based on the growing scholarship of instructional dissent, this study highlights the foundational and strategic aspects underlying these relationships within the context of relating in the classroom and beyond.     

Semi-analytical Monte Carlo simulation of laser-induced fluorescence propagation in an optically participating spray

A semi-analytical Monte Carlo (SMC) simulation was developed to simulate the propagation of laser-induced fluo- rescence (LIF) in an optically participating spray, which simultaneously exhibits spectrally dependent emission, anisotropic scattering, absorption, and re-emission. The SMC simulation is described and then applied to an experimental configuration of a cloud of polydisperse droplets composed of water and sulforhodamine B dye. In the SMC simulation, the collected LIF flux on the remote receptor element is calculated as the global contribution from the emissive source, single, twice, … and nth collision events in any sequence. The effects on the fluorescence photons propagation of spray parameters like the dye concentration, droplets concentration, and droplets size are examined. Three spectral bands representing different optical properties are chosen to analyze the interference of absorption, scattering and re-emission on the detected LIF flux. The obtained spectral LIF flux distribution on the receptor demonstrates a “red shift” phenomenon.