Lower tackle height changing face of women’s rugby, study says

Lowering the legal tackle height in women’s rugby is proving effective in reducing head contacts between players, a world-first study suggests.

University of Edinburgh

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Lower the legal tackle height in women's rugby is providing effectin in reducing head contacts between players, a world-first study suggests. 

Changes to the tackle height law in women’s community rugby in Scotland is linked to reductions in head-to-head and head-to shoulder contacts, the study found.

A study compared more than 11,000 tackles between the 2022/23 season, before the reduced tackle height law was trialed and the 2023/24 season when it was introduced.  

Experts found 21 per cent fewer upright tackles and a 34 per cent increase in tacklers entering the tackle bent at the waist, the recommended technique to reduce contact to the high-risk areas of the head and shoulders.

In collaboration with Scottish Rugby and World Rugby, researchers at the University of Edinburgh used video analysis to study the impact of the lowered tackle height law which World Rugby, the sport’s governing body introduced for community rugby in an attempt to improve safety for players.

The research found a 64 per cent reduction in tacklers making initial contact with the ball carriers head and neck – one of the primary causes of sports related concussion.

Lowering the tackle height was also associated with a 17 per cent reduction in the rate of head-to-head and a 35 per cent reduction in head-to-shoulder contacts for the tackler, the study found.

The study, which is the first to evaluate the lowered tackle height law in women’s community rugby, shows a positive change in player behaviour, researchers say.

The findings can inform future injury prevention initiatives in women’s community rugby in Scotland and beyond, they add.

World Rugby recommended an opt-in international trial of lowering the tackle height from the shoulder to below the sternum as part of a drive to reduce the risk of head-on-head contact and concussion in rugby union games.

The trial was adopted by Scottish Rugby for the 2023/2024 season alongside other nations including Australia, England, France, Ireland, Italy, Japan New Zealand, South Africa and Wales.

Researchers at Moray House School of Education and Sport analysed video footage and injury data from 34 Scottish community women’s rugby matches from the top-level Premiership to the third-tier regional leagues.

The analysis used footage from Scottish Rugby which recorded players’ activity including tackle type, body position, contact point and head contact.

Points of contact between players alongside match events and tackle characteristics were coded according to guidelines developed in collaboration with World Rugby and the University of Cape Town.

They also discovered a 19 per cent reduction in contacts above the sternum – known as the red zone – between the tackler and the ball-carrier. There was a 29 per cent reduction in head-to-head proximity for the tackler, alongside a 33 per cent reduction in head-to-head proximity and a 48 per cent reduction in head-to-shoulder contact for the ball-carrier.

Positively, there were no increases in the rate of the tacklers head making contact with the ball carriers’ knee or hip, which has previously been associated with an increased risk of concussion.

Sanctions - including penalties, advantages and yellow cards related to high tackles increased significantly from 3 to 8 in the 2023/2024 season. The number of tackles decreased significantly, but there was no significant change to the rate of other game player metrics.

The rate of concussions and injuries when comparing the 2022/23 (pre-trial) and 2023/24 (trial) seasons did not change significantly but the number of reported injuries overall was very low and may have impacted these findings.

Lead author, Hannah Walton, of the University of Edinburgh’s Moray House School of Education and Sport, said: “Our findings show reducing the maximum legal tackle height in Scottish women’s community rugby has resulted in a positive change in player behaviour, alongside reductions in tackler and ball-carrier head contact and head proximity to the oppositions head and shoulder. Continued collection of robust tackle and injury data is key to further understanding the effect of the law change ”

Researchers say the study provides valuable data on the impact of the tackle height change in women’s rugby and further studies could help understand the effect of the change on injury and concussion prevention.

Dr Debbie Palmer, of the Institute for Sport, Physical Education and Health Sciences at the Moray House School of Education and Sport, and co-Director for the UK Collaborating Centre on Injury and Illness Prevention in Sport IOC Research Centre, said: “This is the first study evaluating the impact of a lowered tackle height in community women’s rugby and it is good to see, similar to the men’s community study, that initial results are encouraging.

“While injury and concussion numbers were low gathering robust community wide injury surveillance data may help us make more meaningful conclusions. Overall, reductions in head proximity and contact between players is likely to have been beneficial in potentially reducing these concussive events.”

The study builds on the findings of a recent study to assess the impact of the tackle height law change on Scottish men’s community rugby. Evaluations are underway to assess the change on youth community rugby in Scotland.

Scottish Rugby Head of Regional Pathways and Game Development, Neil Graham said: “We look forward to continuing this partnership with University of Edinburgh as we continue to look at ways to evolve the game, keeping player welfare at the centre of the conversation.

“We also look forward to the third and final study on the youth game being released in the near future.”

The study is published in BMJ Open Sport and Exercise Medicine.

The study is part of an international project led by World Rugby to assess the effects of lowering the tackle height in 11 countries including Australia, England, France, Ireland, Italy, Japan, New Zealand, Scotland, South Africa and Wales.

An international team of experts contributed to the study including researchers from the universities of Cape Town and Stellenbosch in South Africa, Calgary in Canada and Leeds Beckett.

The work was funded by World Rugby and Scottish Rugby.

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Journal

BMJ Open Sport & Exercise Medicine

DOI

10.1136/bmjsem-2025-002499 

Subject of Research

People

Article Title

Lowering the maximum legal tackle height in Scottish community women’s rugby: an injury surveillance and video analysis study across two seasons

Article Publication Date

12-May-2025

 

Civil defense units must invest in professionalization and own resources to face climate risks

Research proposes action fronts to increase the organizational capacity of these units in municipalities; expanded coordination with other areas is one of the next steps for the sector

Fundação de Amparo à Pesquisa do Estado de São Paulo

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An ongoing survey by Brazil’s National Center for Monitoring and Early Warning of Natural Disasters is assessing how well municipal civil defense units are integrated with risk management instruments such as warning systems, climate adaptation plans and the relationship with different social groups

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Credit: COPE

As the effects of climate change intensify in urban areas, it is essential to strengthen the organizational capacity of civil defense units to implement disaster risk management, including prevention and mitigation. To contribute to this debate, a study conducted by researchers from the Brazilian National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN) proposes a public policy focused on five fronts.

These are: 1) professionalization of managers and officials in the area; 2) development of capacities adapted to regional specificities and to each biome; 3) allocation of their own budget to municipalities; 4) continuous communication; and 5) social and intersectoral participation.

These actions were designed to address the main challenges identified by the municipal civil defense units themselves in the implementation of the policy. Among these obstacles are difficulties in monitoring and supervising urban expansion in areas prone to flooding and landslides, reduced teams, as well as a lack of professionalization, financial resources, social participation and relationships with other administrative areas.

The research used quantitative and qualitative data collected through mixed methods between October 2020 and December 2021. It included an online questionnaire completed by 1,993 of Brazil’s 5,568 municipalities, interviews with 31 city representatives from five regions of Brazil and ten virtual focus groups with 260 participants.

Some 43% of those interviewed considered themselves poorly qualified to act before a disaster strikes, a level similar to that for acting during (40%) and after (41%) the event. Although more than half say they are capable or very capable of assessing and reporting material damage (60%), identifying and mapping risk areas (54%) and keeping the population informed (53%), 61% do not use an early warning system and 54% do not conduct an inventory of people living in risk areas.

These findings are reported in an article published in the International Journal of Disaster Risk Reduction.

The work also brings together previous findings from the ELOS project – a diagnosis of the needs and capacities of municipal civil defense units carried out from 2021 – and goes one step further, focusing on thinking about solutions to the problems. Part of the quantitative data from ELOS resulted in six publications of the Municipal Diagnosis of Civil Protection and Defense. 

“The intensification of extreme weather events has led to an increase in the area affected by disasters, going beyond municipal territory and even river basins. In the state of Rio Grande do Sul, for example, 96% of municipalities were affected or devastated by floods and landslides in May 2024, prompting the state and other organizations to rethink their approach. In Brazil, we usually mobilize when disaster strikes. But we need to prepare better and think about how to improve coordination between the different administrative bodies and society before the disaster so that the response isn’t always improvised,” says CEMADEN researcher Victor Marchezini, corresponding author of the article and coordinator of ELOS.  

According to the Digital Atlas of Disasters in Brazil, a National Civil Defense platform, between 2014 and 2024, the country recorded about 11,400 incidents of floods, flash floods, heavy rains, tornadoes, storms, cyclones, hail and mass movements. A total of 63 million people were affected during the decade.

The scientists are now working on new data collection with municipal civil defense units, which will run until July 1st, focusing on prevention, as part of the Organizational Capacities for Preparing for Extreme Events (COPE) project. By April 21st, about 1,000 Brazilian municipalities had completed the COPE-CEMADEN project questionnaire.

Aspects of risk mapping, warning systems, the relationship with other bodies in the municipality and with different social groups and how they deal with risk management instruments are being explored. There are questions about the relationship with municipal climate change adaptation plans, fake news and information shared with the press. The form for public managers and civil defense personnel can be accessed here: bit.ly/4dMSYZE.

“Brazilian disaster risk management policies have assigned responsibilities to local governments without assessing whether they have the organizational capacity to make decisions and coordinate with other actors. We’ve seen that insufficient financial and personnel resources and the high turnover of employees, who don’t always receive adequate training, have a direct impact on this reality,” Marchezini, COPE’s coordinator, told Agência FAPESP.

Interdisciplinary

The recently published research was supported by FAPESP through a scholarship awarded to Marchezini and a grant for the funding of COPE.

In addition to analyzing the organizational capacities of civil defense units, COPE aims to co-produce strategies to strengthen the implementation of public policies, integrating teaching, research and extension activities and connecting public managers and communities exposed to disaster risks (read more at: agencia.fapesp.br/51922).  

Throughout their work, the researchers identified gaps in ways to strengthen social participation in risk management, especially when it comes to involving affected communities and other sectors, such as the private sector.

To seek alternatives, in 2024 the group conducted a survey on the perception of risk communication with 5,000 respondents in all Brazilian states. The data are currently being analyzed.

In the study, the group assesses that there is room for future work to examine how public and private organizations can improve their capacity to deal with hazards and vulnerabilities and the new societal challenges associated with disinformation.

About FAPESP

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the state of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration.

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Journal

International Journal of Disaster Risk Reduction

DOI

10.1016/j.ijdrr.2025.105291 

Article Title

Implementation challenges of disaster risk management policies: The organizational capacities of municipal civil defense units

 

Flamingos create water tornados to trap their prey

Stomp dancing, head jerking, chattering and skimming generate whorls and eddies that funnel brine shrimp and small animals into the birds’ mouths

University of California - Berkeley

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Flamingos feed by dragging their flattened beaks forward along the bottom of shallow lakes. To increase the efficiency of feeding, they stomp dance to churn the bottom, create an upwelling vortex with their heads and clap their beaks constantly to draw food, like brine shrimp, into their mouths.

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Credit: Aztli Ortega

Flamingos standing serenely in a shallow alkaline lake with heads submerged may seem to be placidly feeding, but there's a lot going on under the surface.

Through studies of Chilean flamingos in the Nashville Zoo and analysis of 3D printed models of their feet and L-shaped bills, researchers have documented how the birds use their feet, heads and beaks to create a storm of swirling tornados, or vortices, in the water to efficiently concentrate and slurp up their prey.

"Flamingos are actually predators, they are actively looking for animals that are moving in the water, and the problem they face is how to concentrate these animals, to pull them together and feed," said Victor Ortega Jiménez, an assistant professor of integrative biology at the University of California, Berkeley, who specializes in biomechanics. "Think of spiders, which produce webs to trap insects. Flamingos are using vortices to trap animals, like brine shrimp."

Ortega Jiménez and collaborators at the Georgia Institute of Technology in Atlanta; Kennesaw State University in Marietta, Georgia (KSU-Marietta); and the Nashville Zoo will publish their findings this week in the journal Proceedings of the National Academy of Sciences.

The researchers found that flamingos use their floppy webbed feet to churn up the bottom sediment and propel it forward in whorls that the birds then draw to the surface by jerking their heads upward like plungers, creating mini tornados. All the while, the birds’ heads remain upside down within the watery vortex, their angled beaks chattering to create smaller vortices that direct the sediment and food into their mouths, where it's strained out.

The beak of a flamingo is unique in being flattened on the angled front end, so that when the bird’s head is upside down in the water, the flat portion is parallel to the bottom. This allows the flamingo to employ another technique called skimming. This involves using its long, S-shaped neck to push its head forward while rapidly clapping its beak, creating sheet-like vortices — von Kármán vortices — that trap prey.

This suite of active feeding behaviors belie the flamingo's reputation as a passive filter feeder, Ortega Jiménez said.

"It seems like they are filtering just passive particles, but no, these animals are actually taking animals that are moving," he said.

The principles he discovered could be used to design better systems for concentrating and sucking up tiny particles, such as microplastics, from water; better self-cleaning filters, based on chattering; or robots that, like flamingos, can walk and run in mud.

Chattering

Ortega Jiménez, a native of Puebla, Mexico, became fascinated with the feeding behavior of flamingos during a visit to Zoo Atlanta with his wife and daughter before the COVID-19 pandemic. Filming the birds' feeding behavior, he observed only ripples on the surface.

"We don't know anything about what is happening inside. That was my question," he said.

At the time a postdoctoral fellow at Kennesaw State University in Georgia, Ortega Jiménez focused on flamingo feeding as his next research project. He views himself, he said, as a modern-day Darwinian naturalist, investigating the behavior of animals of all types, from nematodes and flies to springtails and birds, focusing on how the animals interact with and manipulate their surroundings, including air, water and electromagnetic fields.

From Kennesaw State he moved to the Georgia Institute of Technology to work in the lab of Saad Bhamla, where he collaborated with engineers, and they gained access to Chilean flamingos at the Nashville Zoo. The team filmed them feeding in a large tray, using a laser to illuminate gas bubbles in the water in order to see the vortices created by the heads and beaks of the animals.

After moving to the University of Maine in Orono as an assistant professor, Ortega Jiménez refined 3D printed models of a flamingo beak and foot to study more precisely the movement of water and particles during the beak clapping, or "chattering," that the birds use when eating.

In 2024, he moved again, to UC Berkeley, where he conducted experiments to see how effective the chattering and foot stomping was in capturing live brine shrimp. The new paper summarizes all of this collaborative work.

At UC Berkeley, he attached a real flamingo beak to an actuator to simulate chattering and added a small pump in the mouth to simulate the tongue and suck up the brine shrimp captured by the mouth. With this setup, he was able to establish that chattering is key to flamingo feeding.

"The chattering actually is increasing seven times the number of brine shrimp passing through the tube," he said. "So it's clear that the chattering is enhancing the number of individuals that are captured by the beak."

Stomp Dancing

The feeding behavior begins with the feet, Ortega Jiménez said. If you look at a flamingo in very shallow water, you can often see its dancing-in-place or circular dancing behavior.

The feet are webbed, but as with many wading birds, they are floppy, so that when the bird lifts a foot, the webbing collapses and comes away from the bottom without the suction that makes it hard for humans to walk in mud. When walking or running, flamingos seem to slide their feet into the water instead of stomping, a technique that could help robots walk in water or mud.

Ortega Jiménez created models of both rigid and flexible flamingo feet to compare how the two designs affect fluid flow, and he found that the floppy feet are much more effective at pushing vortices of sediment out in front of each step. Rigid webbing primarily produces turbulence.

Creating a 3D model of the L-shaped beak, he was able to show that pulling the head straight upward in the water creates a vortex swirling around a vertical axis, again concentrating particles of food. He measured the head speed at about 40 centimeters per second (1.3 feet per second). The small tornados were strong enough to entrap even agile invertebrates, such as brine shrimp and the microscopic crustaceans called copepods.

Chattering also creates vortices around the beak. In this case, the flamingo keeps its upper beak stationary, though it is capable of independent motion, and moves only the lower beak — about 12 times per second during chattering, Ortega Jiménez discovered.

Tien Yee, a co-author of the paper and a professor at KSU-Marrieta, employed computational fluid dynamics to simulate on a computer the 3D flow around the beak and the feet. He confirmed that the vortices do indeed concentrate particles, similar to experiments using a 3D-printed head in a flume with both actively swimming brine shrimp and passively floating brine shrimp eggs.

"We observed when we put a 3D printed model in a flume to mimic what we call skimming, they are producing symmetrical vortices on the sides of the beak that recirculate the particles in the water so they actually get into the beak," Ortega Jiménez said. "It's this trick of fluid dynamics."

His next projects are to determine the role of the flamingo's piston-like tongue and how the comb-like edges of the beak filter prey out of briny and sometimes toxic water.

"Flamingos are super-specialized animals for filter feeding," he said. "It's not just the head, but the neck, their legs, their feet and all the behaviors they use just to effectively capture these tiny and agile organisms."

In addition to Yee, other co-authors of the paper are postdoctoral fellow Pankaj Rohilla, graduate student Benjamin Seleb and Professor Saad Bhamla at Georgia Tech; and Jake Belair of the Nashville Zoo in Tennessee. The work was supported by grants from the National Science Foundation (NSF CAREER iOS-1941933), and the Open Philanthropy Project to Bhamla, and from the University of Maine and UC Berkeley to Ortega Jiménez.

A Chilean flamingo feeding in shallow water.

Chilean flamingo.

Credit

Victor Ortega Jiménez, UC Berkeley

Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2503495122 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Flamingos use their L-shaped beak and morphing feet to induce vortical traps for prey capture

Article Publication Date

12-May-2025

FFAR taps Danforth Center plant scientists for crop research to preserve soil and water health

Research aims to optimize yield and reduce production costs

Donald Danforth Plant Science Center

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ST. LOUIS, MO, May 12, 2025 — The Foundation for Food & Agriculture Research (FFAR) and matching funders today awarded two Seeding Solutions grants totaling over $5 million to the Donald Danforth Plant Science Center (Danforth Center) for crop development research.

FFAR, the Danforth Center, Kansas State University, The Land Institute, the Perennial Agriculture Project and Saint Louis University provided $2,926,098 to a project accelerating the domestication of perennial crops, which are planted once and harvested over several growing seasons. Additionally, FFAR, the Danforth Center, Pennsylvania State University and Valent BioSciences LLC awarded $2,196,825 for research extending the root system of corn to improve synthetic fertilizer efficiency and preserve soil and water health.

“These projects open opportunities for farmer income growth and lower consumer costs by developing efficient, high-performing agricultural systems,” said Dr. Kathy Munkvold, FFAR scientific program director.

The grantees include:

Allison Miller, PhD, Member, Danforth Center; Professor, Saint Louis University

Farming annual crops, like wheat and corn, requires high input costs and can degrade soil over time. Perennial crops, however, have deep roots that can lower farming costs by conserving nutrients and water. Still, few herbaceous perennial species have been domesticated for large-scale agricultural production. Together with collaborators, Miller aims to optimize and expedite the domestication of perennials by developing strategies for screening potential breeding candidates at early life stages. This research team is screening plants at early stages of their lifespan—seeds and seedlings—using genetics and spectral traits separately and in combination to learn which method creates the largest gains in targeted traits and yield. This team is conducting this research on perennial crops in pre-breeding stages—wild species with limited or no breeding—and those in more advanced stages of domestication to establish if the stage of domestication influences a screening method’s success.

“For more than 40 years, perennial alternatives to major grains and legumes have been recognized for their potential to feed people and, through their deep, persistent roots, to provide critical ecosystem services to agricultural lands,” said Miller. “Although perennial herbaceous species are abundant in nature, they were not domesticated by early farmers. This project builds on previous work where we demonstrated that spectral data taken on seeds and seedlings can be used to predict performance of these promising emerging crops. Building on that success, the current project aims to further hone perennial grain development, with the goal of broadening the diversity of species entering the domestication pipeline and shortening the time it takes to develop new crops that benefit people and the planet.”

Christopher Topp, PhD, Member, Danforth Center

Industrial farming relies on large applications of synthetic nitrogen fertilizer. However, a significant portion of fertilizer is not used by the plants, which costs producers money and can affect soil and water health. Topp and his team are exploring the impacts of deep rooted corn, and the symbiotic relationship between corn and arbuscular mycorrhizal fungi, both of which can increase the reach of corn roots. The research team is leveraging unique genetics controlling root system architecture and fungal-corn interactions, including the use of wild corn relatives to optimize root systems for greater nitrogen uptake, increasing yield. The research results can increase producer profits through greater yield and lower input costs, while also improving farmland health.

“This project is born out of a nearly decade-long collaboration with Valent BioSciences to study the interactions of corn roots and mycorrhizal fungi, which are ubiquitous and abundant in agricultural soils,” said Topp. “We have strong preliminary evidence that increasing rooting depth and interactions with mycorrhizal fungi can, separately, capture more nitrogen and increase grain production. This new support from FFAR and Valent BioSciences will allow us to scale the analysis up and test the potential combinatorial effects of deep roots and arbuscular mycorrhizal fungi. We aim to develop nitrogen-smart root systems that leverage natural biological processes to improve the efficiency of crop nitrogen nutrition that will boost yield and reduce input costs, all with fewer environmental downsides.”

About the Donald Danforth Plant Science Center
Founded in 1998, the Donald Danforth Plant Science Center is a nonprofit research institute with a
mission to improve the human condition through plant science. Research, education and outreach
aim to have an impact at the nexus of food security and the environment, and position the St. Louis
region as a world center for plant science. The Center’s work is funded through competitive grants
from many sources, including the National Science Foundation, National Institutes of Health, U.S.
Department of Energy, the Gates Foundation and through the support of individuals and
corporations. Learn more at danforthcenter.org

Media Contacts: 
Danforth Plant Science Center, Karla Roeber, kroeber@danforthcenter.org
FFAR, Ryan Conley, rconley@foundationfar.org

Images available upon request