A method for characterizing high acceleration movements in small-sided football

Small sided football is the most popular area of adult football in the UK, with an estimated 1.5m adults playing every week. Matches are played on smaller pitches using different rules to the 11-a-side game; this results in less stoppage time and a higher volume of ball activity per player. Despite these established differences in playing style and the increase in participation, the types and frequencies of movements performed are not fully understood due to the time consuming nature of current notational analysis methods. Understanding movements is of particular interest to researchers and developers seeking task representative protocols and products for small sided football. The importance of movement type, specifically those with high horizontal plane accelerations, has been demonstrated by recent findings linking traction and shoe stiffness to injury and performance in a number of team sports. In this paper we introduce a new motion analysis technique that uses a combination of inertial sensors and manual notational analysis to describe high acceleration movements in a repeatable and more time effective manner than previously published. A recreational 5-a-side team (mean ± SD: age 17.8 ± 0.26 years, body height 1.77 ± 0.05 m, body mass 74.23 ± 16.25 kg) were observed during one season at a commercial football centre. Player mounted sensors were used to identify 1824 high acceleration movements from three players in seven matches. These movements were then classified using operational definitions adapted from notational analysis literature. This paper outlines a high acceleration movement analysis technique, provides normative high acceleration movement profiles for three individual 5-a-side players, and suggests comparisons to published 11-a-side data. These movement profiles provide a foundation for footwear researchers and product designers to re-align their current practice or products from the 11-a-side game to this more popular style of football

Identifying representative test parameters to assess skin laceration injury risk for individual studs

Skin injuries account for ∼6% of all injuries in rugby union. Skin lacerations resulting from stud–skin interactions in rugby union are frequently caused by stamping in the ruck (Oudshoorn, Driscoll, Dunn, & James, 2016 Oudshoorn, B. Y., Driscoll, H. F., Dunn, M., & James, D. (2016). Procedia Engineering, 147, 496–500. [CrossRef], [Google Scholar] ). Stud design is regulated by World Rugby's Regulation 12, but no supporting evidence currently exists for the selected test parameters used in these standards. Ideally, mechanical tests that assess injury risk should replicate conditions observed during play (Ura & Carré, 2016 Ura, D., & Carré, M. (2016). Procedia Engineering, 147, 550–555. [CrossRef], [Google Scholar] ). Relevant mechanical test parameters, such as foot inbound velocity, stud impact energy, inclination angle and effective mass, can be derived through biomechanical analysis of rugby stamping. However, due to human movement variability, the measured kinetics and kinematics of stamping impacts can have a large range and replicating all possible parameters within a mechanical test device is unfeasible. Identifying different stamp techniques by clustering provides an economical solution

Predation risk for reptiles is highest at remnant edges in agricultural landscapes

1. Preventing biodiversity loss in fragmented agricultural landscapes is a global problem. The persistence of biodiversity within remnant vegetation can be influenced by an animal’s ability to move through the farmland matrix between habitat patches. Yet, many of the mechanisms driving species occurrence within these landscapes are poorly understood, particularly for reptiles. 2. We used scented and unscented plasticine lizard models and wildlife cameras to (1) estimate predation risk of reptiles in four farmland types (crop field, pasture paddock, restoration tree planting and areas with applied woody mulch) relative to the patch edge and remnant vegetation, and (2) examine how predation risk was influenced by temporal change in the matrix (crop harvesting). 3. Birds (55.1%), mammals (41.1%), reptiles (3.4%) and invertebrates (0.5%) attacked models, of which 87% were native species. Mammalian predators were 60.2% more likely to attack scented models then unscented models. Bird predators were not influenced by scent. 4. We found predator attacks on models were highest at edges (49%, irrespective of adjacent farmland type, with a reduced risk within farmland (29%) and remnant patches (33%) (P<0.01). Both mammal and bird predators contributed to high numbers of predation attempts at edges. 5. Removal of crops did not increase predation attempts in crop fields or other farmland types, although predation attempts were significantly lower along the crop transect after harvesting, compared to the woody debris transect. However, numbers of predation attempts were higher in edge habitats, particularly prior to harvesting. 6. Synthesis and applications. Reptiles are at risk of predation by birds and mammals in both remnant patches and the farmland matrix, particularly in edge habitat. Our results demonstrate that edge habitats are potentially riskier for lizards than the farmland. Vulnerability to predation may be increased by a lack of shelter within edge habitats such as by increasing visibility of reptiles to predators. Therefore, to benefit reptiles, land managers could provide shelter (rocks, logs and grasses), particularly between remnants and linear plantings which could improve landscape connectivity.Funding was provided by the Central Tablelands Local Land Services, Lake Cowal Foundation, NSW Office of Environment and Heritage Environmental Trust and the Lake Cowal Foundation

Hypersonic Vehicle Thrust Sensitivity to Angle of Attack and Mach Number

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77092/1/AIAA-2009-6152-843.pd

Images of dissipation layers to quantify mixing within a turbulent jet

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77254/1/AIAA-13435-811.pd

Combustion Species Sensor for Scramjet Flight Instrumentation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76361/1/AIAA-2005-3574-730.pd

A Scramjet Engine Model Including Effects of Precombustion Shocks and Dissociation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76382/1/AIAA-2008-4619-101.pd

Science and society: The Role of Long-term Studies in Environmental Stewardship

Long-term research should play a crucial role in addressing grand challenges in environmental stewardship. We examine the efforts of five Long Term Ecological Research Network sites to enhance policy, management, and conservation decisions for forest ecosystems. In these case studies, we explore the approaches used to inform policy on atmospheric deposition, public land management, land conservation, and urban forestry, including decisionmaker engagement and integration of local knowledge, application of models to analyze the potential consequences of policy and management decisions, and adaptive management to generate new knowledge and incorporate it into decisionmaking. Efforts to enhance the role of long-term research in informing major environmental challenges would benefit from the development of metrics to evaluate impact; stronger partnerships among research sites, professional societies, decisionmakers, and journalists; and greater investment in efforts to develop, test, and expand practice-based experiments at the interface of science and society

Pressure sensor calibration for measuring stud-player impacts

In rugby union, laceration injuries can occur from players stamping on opponents in the ruck. To measure the stud-skin interaction during stamping movements, pressure sensors can be used. Pressure sensor calibration techniques have highlighted the need to perform calibrations using appropriate impact dynamics. A pilot study with seven rugby players informed the expected peak forces and loading rates of rugby stamps. Subsequently, a custom calibration procedure was developed, using a drop hammer and force platform to replicate the experimentally observed forces and loading rates. The conventional calibration of the pressure sensor system, supplied by the manufacturer, overestimated total force by 132%. The method described in this paper resulted in a mean error of 7.5%. This study describes a simple and effective calibration procedure for using pressure sensors when measuring the peak force from stud-player impacts. The method has potential to be used as an improved calibration protocol when the expected peak force range of the measured event is between 1800 and 3000 N. The calibrated pressure sensors will be used to obtain kinetic data from stamping events in the ruck in rugby union

Causation events of stud laceration injuries in rugby union

Laceration injuries in rugby union account for approximately 6% of all injuries sustained during match play. Commentators often cite the design of studded footwear as a causal factor in laceration injuries. In order to assess the laceration injury risk of different stud designs, there is a need to develop a testing protocol that is able to replicate the laceration injury event. This study used a questionnaire to identify the play scenarios that result in laceration injuries. The questionnaire was answered by 191 rugby players, of which 72% had experienced one or more stud injuries during their career which hindered them playing rugby. Half of the laceration injuries described by the respondents came from the ruck, and 27% from a tackle. When analysing free-text responses, a deliberate stamp was described in 35% of the responses and a tackle from behind was described in 14% of responses. These injury scenarios are considered to be the dominant cause of laceration injuries. In future work the identified injury scenarios will be replicated in simulated play and kinetic and kinematic measurements will be recorded. This will inform test parameters for future assessment of laceration injury risk of stud designs