Validation of a laboratory method for evaluating dynamic properties of reconstructed equine racetrack surfaces.

BackgroundRacetrack surface is a risk factor for racehorse injuries and fatalities. Current research indicates that race surface mechanical properties may be influenced by material composition, moisture content, temperature, and maintenance. Race surface mechanical testing in a controlled laboratory setting would allow for objective evaluation of dynamic properties of surface and factors that affect surface behavior.ObjectiveTo develop a method for reconstruction of race surfaces in the laboratory and validate the method by comparison with racetrack measurements of dynamic surface properties.MethodsTrack-testing device (TTD) impact tests were conducted to simulate equine hoof impact on dirt and synthetic race surfaces; tests were performed both in situ (racetrack) and using laboratory reconstructions of harvested surface materials. Clegg Hammer in situ measurements were used to guide surface reconstruction in the laboratory. Dynamic surface properties were compared between in situ and laboratory settings. Relationships between racetrack TTD and Clegg Hammer measurements were analyzed using stepwise multiple linear regression.ResultsMost dynamic surface property setting differences (racetrack-laboratory) were small relative to surface material type differences (dirt-synthetic). Clegg Hammer measurements were more strongly correlated with TTD measurements on the synthetic surface than the dirt surface. On the dirt surface, Clegg Hammer decelerations were negatively correlated with TTD forces.ConclusionsLaboratory reconstruction of racetrack surfaces guided by Clegg Hammer measurements yielded TTD impact measurements similar to in situ values. The negative correlation between TTD and Clegg Hammer measurements confirms the importance of instrument mass when drawing conclusions from testing results. Lighter impact devices may be less appropriate for assessing dynamic surface properties compared to testing equipment designed to simulate hoof impact (TTD).Potential relevanceDynamic impact properties of race surfaces can be evaluated in a laboratory setting, allowing for further study of factors affecting surface behavior under controlled conditions

Modelling the Interaction Between Racehorse Limb and Race Surface

AbstractMusculoskeletal injuries are the leading cause of racehorse fatalities and attrition. Race surface mechanics affect racehorse limb biomechanics, and therefore can affect musculoskeletal injuries. Installation of experimental race surfaces to determine their effect on racehorse limb kinematics is not financially feasible. Furthermore, field data collection is time consuming, labor intensive, and requires the use of live animals. Computational modelling provides an economical option to survey a wide range of surface mechanics and resulting effects on racehorse limb motions. This research aimed to develop and evaluate an integrated racehorse limb and race surface computational model. The interaction of a virtual galloping racehorse impacting virtual race surfaces was modelled in SIMM using combined forward/inverse dynamics. In vivo kinematic data were averaged to determine proximal forelimb, trunk, and hindlimb kinematic model profiles throughout gallop stance, as well as distal forelimb initial conditions. All distal forelimb joints and hoof translations were free to respond to external forces applied by the race surface model during stance. Race surface model coefficients were determined from previously measured race surface mechanics and forward dynamic simulations of a track-testing device. Simulation results were compared to distal forelimb motions of actual galloping racehorses on mechanically measured race surfaces. Model predicted kinematic profiles (metacarpophalangeal angle and hoof translations) had qualitative shapes and peak magnitudes within ranges of experimental data. Simulated peak metacarpophalangeal angle and hoof translations were within 11 degrees and 4cm respectively. Future model applications include estimation of the effects of variation in race surface parameters on racehorse limb biomechanics

A longitudinal study of influences on alcohol consumption and related harm in Central Australia: with a particular emphasis on the role of price.

Made available by the Northern Territory Library via the Publications (Legal Deposit) Act 2004 (NT).Northern Territory, Department of Health, Central Australian Aboriginal Congres

Correction: Validation of a Laboratory Method for Evaluating Dynamic Properties of Reconstructed Equine Racetrack Surfaces.

[This corrects the article DOI: 10.1371/journal.pone.0050534.]

Musculoskeletal Outcomes From Chronic High-Speed, High-Impulse Resistance Exercise

While bones and muscles adapt to mechanical loading, it appears that very specific types of stimuli must be applied to achieve osteogenesis. Our study assessed musculoskeletal outcomes to 30 training sessions on an Inertial Exercise Trainer (Newnan, GA). Subjects (n = 13) performed workouts with their left leg, while their right served as an untreated control. Work-outs entailed three 60-s sets each of knee extension, hip extension and calf press exercises, separated by 90-s rests. Before and after the 30 training sessions, subjects underwent strength tests (knee and ankle extensors of both legs), DEXA scans (hip, knee and ankles of both legs), and blood draws. After 30 training sessions 2 × 2 ANOVAs showed left leg peak torques rose significantly. 2 × 2 ANCOVAs, with bone scan area as a covariate, showed significant left leg calcaneal bone mineral content ( + 29 %) and density ( + 33 %) increases after 30 training sessions. A significant decline in C-terminal telopeptides of type I collagen, a blood marker of bone resorption, also occurred after 30 training sessions. The Inertial Exercise Trainer’s large volume of training session repetitions elicited high peak force, peak acceleration and impulses that likely provided a mechanical loading stimulus that evoked calcaneal accretion

My Baby, My Move+: Feasibility of a Community Prenatal Wellbeing Intervention

Background Excessive gestational weight gain (EGWG), insufficient prenatal physical activity and sleep, and poor psychological wellbeing independently increase risks for adverse maternal and infant outcomes. A novel approach to mitigate these risks is utilizing peer support in a community-based prenatal intervention. This study assessed the feasibility (acceptability, demand, implementation, and practicality) of a remotely delivered prenatal physical activity intervention called My Baby, My Move + (MBMM +) that aims to increase prenatal physical activity, enhance mood and sleep hygiene, and reduce EGWG. Methods Participants were recruited through community organizations, local clinics, and social media platforms in the Fall of 2020 and Spring of 2021. Eligible pregnant women were randomized to either the MBMM + intervention or the control group. Each group met over Zoom for 16 sessions (twice weekly for 60 min over 8 weeks) to learn either behavioral change and wellbeing knowledge and skills (MBMM +) or knowledge and skills related to parenting (control group). Multiple methods of evaluation to better understand the feasibility of the intervention were conducted. Results A total of 49 women (25 MBMM + intervention, 24 control) completed both pre- and post-survey assessments and were included in the analyses. A subsample of 19 (39%) intervention participants completed a combination of semi-structured interviews/surveys to assess acceptability, demand, implementation, and practicality. Participants expressed positive feedback regarding acceptability (satisfaction and intent to continue use) and were extremely likely or likely to recommend the program to a friend (demand). Implementation metrics were assessed by observation and feedback forms completed by peer leaders and demonstrated high-quality control. Findings suggest that the intervention was practical due to remote sessions and cost-effectiveness. Conclusion The MBMM + intervention was deemed to be a feasible intervention with high acceptability, demand, implementation, and practicality. These findings can be used to inform the scalability of the intervention and implementation of a larger efficacy trial

The impacts of discriminatory experiences on lesbian, gay and bisexual people in sport

This study examines the nature and impact of sexist and homophobic discrimination experienced by lesbians, gays and bisexuals (LGB) in Australian sporting settings. A mixed methods online survey was utilized to collate participant experiences. The findings suggest that, in sport, participants experienced sexism directly and systemically, and homophobia explicitly and implicitly. Women experienced sexism and homophobia, whilst men reported more homophobic events. The most mentioned impacts of discrimination were negative emotions such as sadness, anger, distress and shame, followed by negative engagement with sport such as disliking sport, or avoiding or leaving sport. The well-recognized benefits of sport such as physical and mental well-being, social connections, enjoyment, positive identity and achievement may be more difficult to realize within this context of significant social stress

Healthcare recommendations for Joubert syndrome

Joubert syndrome (JS) is a recessive neurodevelopmental disorder defined by a characteristic cerebellar and brainstem malformation recognizable on axial brain magnetic resonance imaging as the "Molar Tooth Sign". Although defined by the neurological features, JS is associated with clinical features affecting many other organ systems, particularly progressive involvement of the retina, kidney, and liver. JS is a rare condition; therefore, many affected individuals may not have easy access to subspecialty providers familiar with JS (e.g., geneticists, neurologists, developmental pediatricians, ophthalmologists, nephrologists, hepatologists, psychiatrists, therapists, and educators). Expert recommendations can enable practitioners of all types to provide quality care to individuals with JS and know when to refer for subspecialty care. This need will only increase as precision treatments targeting specific genetic causes of JS emerge. The goal of these recommendations is to provide a resource for general practitioners, subspecialists, and families to maximize the health of individuals with JS throughout the lifespan