RESUMO
Analysing player kinematics during a match using "gold-standard" 3D video-based motion analysis techniques is a difficult prospect indeed. The development of small, wireless, wearable sensors offers the potential to reduce the challenges of measuring kinematics during match-play without hindering performance. The present study examined the viability of using wireless tri-axial accelerometers to examine whether key performance measures of drag flicks executed by expert specialist drag-flickers are predicted by the kinematics of the striking phase. Linear mixed models were used to examine whether the speed and accuracy of players' drag flicks were predicted by the duration of stick-ball contact, and the kinematics of the lead lower limb at stick-ball contact and ball release. Results revealed that stick and lead lower limb kinematics significantly predicted shot accuracy but not shot speed. Shorter drag-time predicted more accurate flicks (p = 0.03) as did a more vertical leg at stick-ball contact (p = 0.016) and a more horizontal thigh at ball release (p = 0.001). This may indicate that there are more ways to produce fast drag flicks than accurate ones. This study illustrates that wireless tri-axial accelerometers can be used on-field to measure the effects of kinematics on key performance measures.
Assuntos
Acelerometria/instrumentação , Hóquei/fisiologia , Extremidade Inferior/fisiologia , Destreza Motora/fisiologia , Dispositivos Eletrônicos Vestíveis , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Fadiga Muscular/fisiologia , Estudos de Tempo e MovimentoRESUMO
Research has revealed that individual soccer goalkeepers respond differently to penalty shots, depending on their specific perceptual and motor capabilities. However, it remains unclear whether analogous differences exist between individual penalty takers, and if specialising in penalty taking affects the occurrence of differences between individuals. The present study examined individual differences in penalty shot speed and accuracy for specialists in penalty taking versus non-specialists. Expert specialist field hockey drag flickers and equivalently skilled non-specialists performed drag flicks towards predetermined targets placed in the face of a standard field hockey goal. Comparisons in shot speed and accuracy were made at a group level (specialists vs. non-specialists) as well as between individuals. Results revealed differences in both speed and accuracy between specialists, but only differences in speed between non-specialists. Specialists generated significantly greater shot speed than non-specialists (P < .001) and were more accurate to some, but not all, targets (top left, P < .006, bottom left P < .001). In addition, it was found that in specialists increasing practice correlated with decreasing accuracy. This may indicate that excessive practice could potentially reduce a specialist's accuracy in shooting towards specific targets.
Assuntos
Hóquei/fisiologia , Destreza Motora/fisiologia , Desempenho Atlético/fisiologia , Humanos , MasculinoRESUMO
BACKGROUND: While large-scale disasters are uncommon, our society relies on emergency personnel to be available to respond and act. Faith in their availability may lead to a false sense of security. Many emergency personnel obligate themselves to more than one agency and so may be overcommitted, leaving agencies with unfilled positions in a disaster. We sought to describe the frequency of overcommitment of emergency medical services (EMS) personnel in North Carolina. METHODS: We conducted a cross-sectional study utilizing the Credentialing Information System (CIS) of the North Carolina Office of EMS. The CIS database manages demographic and certification information for all EMS personnel in North Carolina. The state is divided into 100 EMS systems based on county boundaries. Utilizing de-identified provider data from the CIS, we collected system(s) affiliation(s) and level of certification. To calculate an overcommitment rate per system, we divided the number of personnel with more than one system affiliation by total number of system roster personnel. To compare urbanicity and certification level with overcommitment, analysis of variance and the chi-square test were used, respectively. RESULTS: North Carolina credentials 14,717 EMS providers (8,346 EMT, 1,709 EMT-intermediate (EMT-I), 4,662 EMT-paramedic (EMT-P)). Of these, 10,928 (74%) are affiliated with a single system. Of the 3,789 committed to more than one system, 3,020 (21%) were committed to two systems, 571 (4%) to three, 138 (1%) to four, and 60 (<1%) to five or more. EMT-Is and EMT-Ps were more likely to be overcommitted when compared to EMTs (37, 32, 20% respectively, p < 0.0001). Statewide, the median overcommitment rate for EMS systems was 24% (IQR 16-37%). Personnel working in systems servicing less densely populated areas were more likely to be overcommitted: 33% wilderness, 29% rural, 20% suburban and 11% urban (p < 0.0001). Additionally, 40% wilderness, 23% rural, 4% suburban, and 0% urban systems had >37% of their personnel engaged in 9-1-1 response in more than one system. CONCLUSION: Many EMS personnel have multiple EMS commitments. Disaster planners and emergency managers should consider overcommitment of emergency responders when calculating the work force on which they can rely.
Assuntos
Planejamento em Desastres , Serviços Médicos de Emergência , Auxiliares de Emergência , Sistemas de Informação , Certificação , Estudos Transversais , Humanos , North CarolinaRESUMO
Dynamic transcriptional changes are widespread in rapidly dividing developing embryos when cell fate decisions are made quickly. The Caenorhabditis elegans embryo overcomes these constraints partly through the rapid production of high levels of transcription factor mRNAs. Transcript accumulation rates for some developmental genes are known at single-cell resolution, but genome-scale measurements are lacking. We estimate zygotic mRNA accumulation rates from single-cell RNA sequencing data calibrated with single-molecule transcript imaging. Rapid transcription is common in the early C. elegans embryo with rates highest soon after zygotic transcription begins. High-rate genes are enriched for recently duplicated cell-fate regulators and share common genomic features. We identify core promoter elements associated with high rate and measure their contributions for two early endomesodermal genes, ceh-51 and sdz-31. Individual motifs modestly affect accumulation rates, suggesting multifactorial control. These results are a step toward estimating absolute transcription kinetics and understanding how transcript dosage drives developmental decisions.