Division of Natural Sciences

From Huffy to high tech, it's been a wild ride

Rachel Sauer — Fri, 05 Sep 2025 19:29:05 +0000

From Huffy to high tech, it's been a wild ride Rachel Sauer Fri, 09/05/2025 - 13:29

Rachel Sauer

For 91ɫ�� alumnus Todd Carver, what he learned in the lab as a student inspired industry-rocking innovation in developing digital bike-fitting technology

For a long time, one of the unspoken truths of cycling was that if you ride hard and long enough, it’s going to hurt: foot or hand numbness, back pain, shoulder pain, the list is extensive.

Every rider feels it differently. For Todd Carver (IntPhys’00, MIntPhys’02), “my lower back is the problem. I struggled with my position but finally got to the point where I could ride pain-free as I understood the human body more and was actually able to make changes to my position on the bike.

“Plus, the bike’s adjustable, right, so you can move the seat, you can adjust your touchpoints to the bike, your hands, butt and feet can all be adjusted. And if you don’t adjust those and just plop yourself on the bike, there’s a chance you’re not going to perform well and you’re going to get injured.”

91ɫ�� alumnus Todd Carver (IntPhys’00, MIntPhys’02) co-founded Retül, a bike fitting and product matching technology now used by professional cycling teams, performance centers, rehabilitation centers and bicycle retailers worldwide.

While working with Bill Byrnes and Rodger Kram, associate professors emeritus in the 91ɫ�� Department of Integrative Physiology, in the Applied Exercise Science Laboratory during his graduate studies, Carver began wondering if competitive cycling—or even long-distance recreational cycling—needed to end in pain.

“The big thing the cycling world was missing was information about the rider—the human aspect,” Carver explains. “How should riders fit on a bike? How do you position a rider to be powerful, efficient and perform well? All the things I was learning in my academic career under Bill Byrnes and Rodger Kram—the focus of my research—was in predicting cycling performance, who’s going to perform well and who’s not.”

The problem was, there just weren’t that many tools to assess a rider’s position on their bike and give them a three-dimensional, dynamic bike fit. So, Carver and two colleagues developed one: Retül, a bike fitting and product matching technology now used by professional cycling teams, performance centers, rehabilitation centers and bicycle retailers worldwide.

Retül wrought such a change in the cycling world that Specialized acquired it in 2012. Now, as head of human performance for Specialized, Carver continues to innovate at the vanguard of cycling fit and performance.

“Riders just want to be pain free,” Carver says. “And even if they don’t care about being fast, they don’t want to push on the pedal and not go or push on the pedal and it hurts.”

Bike = freedom

Carver discovered young that pushing on a bike pedal is bliss and freedom in equal measure. “My first bike was a Huffy, and it was frickin’ rad,” he recalls. “As a kid, I realized that on a bike I can go way farther. So, I had this Huffy that I rode around the neighborhood, and it gave me a lot of freedom as a kid.”

Celebrate cycling (and correctly fitted bikes) Sunday, Sept. 7, at the Buffalo Bicycle Classic!

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His first “real” bike as a recreational and then competitive cyclist was a mountain bike, which he rode while figuring out what to do during the several years he lived in Breckenridge between high school and college. “I moved to Breckenridge and just got hooked on endurance sports, especially mountain biking, and I said, ‘I need to go study the science of this.’”

He came to 91ɫ�� and joined the cycling team, eventually realizing that he didn’t want to pursue professional cycling and that the science of riding held a lot more fascination for him. Plus, he brought to the performance lab and insiders knowledge of the problems cyclists could have.

“One of the studies that we did with Rodger (Kram) was measuring aerodynamic drag on bikes, and I saw how big of an opportunity fit was,” Carver says. “You can have a really fast bike, and that’s good, but the human body makes up 80 to 90% of drag.

Todd Carver (left) works with a cyclist to gather data for a bike fitting. (Photo: Todd Carver)

“To this day, we still do that analysis with all of our pro riders. We take them to the velodrome, measure aerodynamics and then work with fit to try to improve it. I’d almost say that one of the biggest impacts we’ve had is helping send professional and career cycling more toward science.”

After earning his master’s degree, Carver worked at the 91ɫ�� Center for Sports Medicine, where he and an engineer colleague, Cliff Simms, soon realized that people were flying in from as far as Europe to get fitted for bikes. He wondered why they couldn’t get fitted in their hometowns, “and it really came down to the technology. For a bike shop to get the digital technology was too expensive and it was too hard to run—you basically would need a master’s degree in biomechanics to do it—so this engineer friend and I started to look at how we could break down those barriers.”

They began developing a motion-capture system that measures length and trigonometric relation between small LED markers placed all over the cyclist’s body and synchronized to flash at certain times, a process that happens in milliseconds. 3D cameras positioned around the rider record the data, which is immediately analyzed and used to fit riders to bikes with millimeter precision.

Affordable, portable, easy to use

With partner Franko Vatterott, Carver and Simms founded Retül in 2007 with a goal of making bike fitting more affordable, portable, easy to use and data driven.

“I say I got my MBA starting a company,” Carver says. “I knew nothing, and I learned it starting a company. One big thing we learned is you better have a darn good product, and what we felt we had was a really good product, so that made some things easier. We didn’t need to take investment initially; we were able to just bootstrap it and work off the money we were making (during development).”

They also were building a database containing everything they were learning about different types of bodies and how they fit on bikes—data they knew would be appealing to bike manufacturers. In fact, he adds, the goal was always to sell to Specialized, which had worked with doctors on ergonomic design and lacked only data from digital fitting.

Todd Carver (right) shows a cyclist data from a digital bike fitting. (Photo: Todd Carver)

They initially worked with professional riders, drawing on connections Carver had made with riders in 91ɫ�� performance labs, and marketed Retül to fitting pro teams. “Then bike shops were coming to us saying, ‘We’d like to buy one of your systems.’

“From the rider point of view, what I was hearing was, ‘Wow, that feels way better, and it’s easier for me to pedal’ or ‘That completely got rid of my injury and now I can push harder.’ The problem might not be the bike itself, it just might be the saddle or the shoe or the footbed, or it just might be that the rider needs to reposition themself on the bike. From the rider point of view, that’s powerful because they could see that bike shops weren’t always trying to sell them a new bike, but had the data to say, ‘Let’s try a new saddle.’”

‘More fun with data’

As head of human performance for Specialized, Carver continues to work with riders at all levels and in all areas of cycling.

“We work in optimizing athlete and product performance using science,” Carver says. “In addition to fitting pros and selling fit systems to retailers, we do a lot of research and development—we take that fit knowledge we have and are able to then use that for ergonomic design of saddles, shoes and hand grips.

“How hand grips are shaped, for example, affects how a rider’s hand sits, which can mean the difference between a comfortable hand and one that goes numb. So, what we do is prototype and test and gather data for better design. We do so much work in saddles, which is the hardest thing on a bike to get right, so we’re always testing with pressure mapping.”

The overarching goal, Carver says, is to solve riders’ problems, “and that’s more fun with data.”

Carver often considers whether his life’s work is science or art, and figures it lives somewhere between the two: “We use scientific tools, have all these ranges, but we can’t know everything from that. I think that’s where the art comes in. You need to work with a lot of different riders—some who just want to ride bikes down to the grocery store and don’t want to be aerodynamic or fast—and you have to be able to empathize with that as well as the more competitive side of cycling. You have to have the human side, too, and really read people, have really good interviewing skills and listening skills to know what they want to do on a bike.

"I think I can empathize because I still love to ride, and I still feel that freedom when I get on my bike.”

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For 91ɫ�� alumnus Todd Carver, what he learned in the lab as a student inspired industry-rocking innovation in developing digital bike-fitting technology.

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91ɫ�� scholar receives Fulbright support to study fossil mammals in Poland

Rachel Sauer — Fri, 22 Aug 2025 19:23:11 +0000

91ɫ�� scholar receives Fulbright support to study fossil mammals in Poland Rachel Sauer Fri, 08/22/2025 - 13:23

Professor Jaelyn Eberle will teach and pursue a hypothesis that a Cretaceous land bridge between Asia and North America was a dispersal route for land mammals at the time

Jaelyn Eberle, a 91ɫ�� professor of geological sciences and CU Museum of Natural History curator of fossil vertebrates, has received a Fulbright U.S. Scholar award to study the extensive collection of Cretaceous (about 75 million years old) Mongolian mammals housed at the Institute of Paleobiology in Warsaw, Poland.

Eberle will travel to Poland Aug. 31 to begin work comparing the Mongolian mammal collection with fossil mammals that she and her colleagues discovered on the North Slope of Alaska, in the hopes of identifying some of the earliest mammals to cross from Asia into North America via Beringia, a prehistoric land bridge that once connected the two continents. Along with Professor Lucja Fostowicz-Frelik, Eberle also will team-teach a graduate seminar on the Cretaceous-Paleogene boundary for the BioPlanet Doctoral School in Poland, which attracts PhD students in biology, geology and biochemistry from across Europe.

Jaelyn Eberle, a 91ɫ�� professor of geological sciences and CU Museum of Natural History curator of fossil vertebrates, has received a Fulbright U.S. Scholar award to study the Cretaceous Mongolian mammals housed at the Institute of Paleobiology in Warsaw, Poland.

“Until now, my research has focused mostly on North American fossil mammals,” Eberle explains. “The Fulbright award allows me to broaden my research to include ancient Mongolian mammals and collaborate with the foremost expert on them, Dr. Fostowicz-Frelik. I am also excited to co-teach a class with Dr. Fostowicz-Frelik; this will build my knowledge of the Eurasian fossil record and inject new content, perspective and teaching styles into my courses at 91ɫ��.

“Being immersed in the language and culture of Poland for four months and teaching PhD students from across Europe will also give me perspective on how to better support CU students from international backgrounds, too.”

Fulbright U.S. Scholars are faculty, researchers, administrators and established professionals teaching or conducting research in affiliation with institutes abroad. Fulbright Scholars engage in cutting-edge research and expand their professional networks, often continuing research collaborations started abroad and laying the groundwork for forging future partnerships between institutions.

“Professor Eberle’s fascinating research is important not only because it advances scientific knowledge, it also expands the Museum Institute’s vibrant international collaborations, helping us to connect with scholars around the globe,” says Nancy Stevens, director of the Museum Institute and professor of anthropology.

Upon returning to their home countries, institutions, labs and classrooms, they share their stories and often become active supporters of international exchange, inviting foreign scholars to campus and encouraging colleagues and students to go abroad.

More than 800 individuals teach or conduct research abroad through the Fulbright U.S. Scholar Program annually. In addition, more than 2,000 Fulbright U.S. Student Program participants—recent college graduates, graduate students and early-career professionals—participate in study/research exchanges or as English teaching assistants in local schools abroad each year.

Fulbright is a program of the U.S. Department of State, with funding provided by the U.S. Government. Participating governments and host institutions, corporations and foundations around the world also provide direct and indirect support to the program, which operates in over 160 countries worldwide.

As a Fulbright U.S. Scholar, Eberle will further her study of fossil mammals, their evolution during past intervals of global warmth and their dispersal across the Northern Hemisphere when polar land bridges connected North America to both Asia and Europe.

“I hypothesize that some of the Cretaceous Alaskan mammals belong to Asian lineages; if true, this would provide direct evidence that Beringia was a dispersal route for land mammals at the time,” Eberle explains. “The Alaskan fauna preserves the northernmost known mammals of the Mesozoic Era (or Age of Dinosaurs), and our team’s latest findings mean it may also include among the earliest mammalian immigrants from Asia to North America.

Jaelyn Eberle (foreground, yellow jacket) and her colleagues quarry for tiny vertebrate fossils in Alaska's Prince Creek Formation. (Photo: Kevin May)

Many of the mammal teeth Jaelyn Eberle studies are the size of sand grains. This is a tooth of the tiny Alaskan mammal Sikuomys mikros (meaning "tiny ice mouse") that lived in northern Alaska about 72 million years ago. (Photo: Jaelyn Eberle)

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Professor Jaelyn Eberle will teach and pursue a hypothesis that a Cretaceous land bridge between Asia and North America was a dispersal route for land mammals at the time.

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Top illustration: James Havens

91ɫ�� scientist named 2025 Pew Biomedical Scholar

Rachel Sauer — Tue, 19 Aug 2025 14:34:17 +0000

91ɫ�� scientist named 2025 Pew Biomedical Scholar Rachel Sauer Tue, 08/19/2025 - 08:34

Biochemist Vignesh Kasinath will receive four years of funding ‘to uncover fundamental insights about human health and disease’

Vignesh Kasinath, a 91ɫ�� assistant professor of biochemistry, has been named a 2025 Pew Biomedical Scholar.

Kasinath is among a cohort of 22 early-career scholars who will receive four years of funding from the Pew Charitable Trusts “to uncover fundamental insights about human health and disease.”

“For 40 years, Pew has supported young, talented researchers as they take creative approaches to solving big scientific questions,” said Donna Frisby-Greenwood, Pew’s senior vice president for Philadelphia and scientific advancement. “This new class continues that legacy, and we look forward to seeing where their discoveries lead.”

Vignesh Kasinath, a 91ɫ�� assistant professor of biochemistry, has been named a 2025 Pew Biomedical Scholar.

The members of the 2025 cohort are all early-career, junior faculty and are the 40th group of Pew scholars to be awarded funding since the program’s founding in 1985.

“Pew-funded scientists have long contributed to biomedical research discoveries that have improved human health,” said Lee Niswander, a 1995 Pew scholar and chair of the program’s national advisory committee. “I’m confident this new class of scholars, with their innovative and creative approaches to scientific research, will continue this tradition.”

Kasinath’s research explores how cells “silence” transposons, which are genetic elements whose movement within the genome can disrupt the function of genes. The human genome, he notes, is riddled with transposons, DNA sequences that promote genetic instability by replicating and integrating into additional chromosomal locations.

To maintain genomic integrity, cells have surveillance systems that distinguish between transposons and normal genes and epigenetically silence the transposons to prevent their replication. “Recently, my group has found that one such system, human silencing hub (HUSH), interacts with specific RNA-binding proteins that have known roles in combating retroviral integrations in the human genome,” he says.

“Now, using cutting-edge techniques in cryo-electron microscopy, biochemistry and RNA-protein interaction mapping, we will determine how RNA-binding proteins aid HUSH in the recognition of transcriptionally active transposons, how HUSH interacts with chromatin and RNA to silence these elements and how mutations in HUSH perturb these interactions.”

Given that HUSH functions as an RNA-mediated gene silencer, Kasinath adds, his work could lead to novel therapeutic strategies for treating cancers and other human diseases associated with transposon invasion, by epigenetically silencing such translocations that often result in gene fusions through with cancer can manifest.

“I am thrilled to be part of the Pew!" Kasinath says. "I have interacted with many Pew scholars who have been incredibly supportive and generous with their time. This Pew award affirms my lab’s commitment to the exciting problems we are pursuing.”

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Biochemist Vignesh Kasinath will receive four years of funding ‘to uncover fundamental insights about human health and disease.'

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Video games don’t rot your brain—they train it

Rachel Sauer — Mon, 18 Aug 2025 20:06:22 +0000

Video games don’t rot your brain—they train it Rachel Sauer Mon, 08/18/2025 - 14:06

Blake Puscher

91ɫ�� scientists find that playing video games comes with small but significant cognitive benefits

Ever since video games began to gain widespread popularity, some have questioned how playing them consistently affects people, especially mentally. Like with TV, the internet, social media and AI, the tendency has been to assume negative effects. However, a number of studies have suggested that playing video games can help strengthen people’s cognitive abilities.

Despite similar research findings, many of the studies disagree on the size of this effect and to which areas of cognition it applies—perhaps, in part, because of the limitations inherent to their typically cross-sectional approach.

A team of 91ɫ�� scientists including Shandell Pahlen, Anqing Zheng, Robin P. Corley, Naomi P. Friedman, Sally J. Wadsworth and Chandra A. Reynolds, all members of 91ɫ��’s team within the CATSLife project, aim to address these uncertainties with a longitudinal study on video games and cognitive health. CATSLife stands for Colorado Adoption/Twin Study of Lifespan behavioral development and cognitive aging.

Chandra Reynolds, a 91ɫ�� professor of psychology and neuroscience, and her research colleagues found small, positive cognitive benefits of playing video games.

“We can leverage the twins and siblings’ similarities and differences to understand aspects of behaviors and cognitive abilities,” Reynolds explains, a 91ɫ�� professor of psychology and neuroscience, “especially as they relate to how well people maintain their cognitive functioning, not only now, but eventually we hope to continue following them as they transition into midlife.”

Video games and cognitive health

Video games are an accessible way to engage one’s mind for several reasons. Like board games, video games do not require much in the way of physical ability, unlike sports and other such ways to exercise the mind. Additionally, video games are widely popular, with 2.7 billion gamers worldwide as of early 2025, according to Statista.

These traits suggest that video games could be used as a tool to support cognitive health, but this assertion raises some questions: What are the specific abilities that comprise generalized cognitive functioning, and how can scientists determine whether video games serve this purpose?

The study covered three important cognitive domains: processing speed, working memory and spatial reasoning. It included 1,241 individuals from CATSLife between 28 and 49 years old who had taken at least one of these tests. Some of the participants played video games and some did not, so the effects of playing video games were determined based on what video games they played. These games were categorized broadly into Action+, Puzzle+, and Other genres. The plus signs refer to the fact that the categories include genres that are not usually described with the base name, like life simulation games being included in Puzzle+ even though they aren’t puzzle games.

Reverse selection

One argument against prior studies suggesting that video games provide a cognitive benefit is the concept of reverse causation. In this case, reverse causation refers to certain people’s cognitive skills making them more likely to play video games, as opposed to playing video games causing an increase in cognitive skills.

Reverse causation is therefore part of the nature vs. nurture discourse, and as such, the point is not that engaging in an activity can’t improve people’s abilities, but that part of the correlation between activity and ability comes from those who already have above-average abilities choosing to engage in activities that take advantage of them. For example, a hypothetical study that compared Olympic runners with people who never run without accounting for reverse causation would overestimate the physical benefits of running, because a large part of the gap between the two groups is baked in: Most people can’t reach the level of Olympic athletes just by exercising.

This study factored in the participants’ baseline cognitive ability by looking at their adolescent IQ scores. “We’re fortunate that we had a longitudinal design,” Reynolds says, “and that we’ve assessed our participants multiple times over their earlier development into adolescence. Most studies of video games are cross sectional, and they don’t have indices of people’s cognitive performance at earlier ages.”

The researchers also considered several variables associated with performance on specific cognitive tasks. These included age, sex and educational attainment. The first two of these are especially important, because the genre of video games that people play varies within these demographics. Specifically, women and older adults are more likely to play Puzzle+ games, and men and younger people are more likely to play Action+ games.

91ɫ�� researcher Chandra Reynolds and her colleagues found that spatial reasoning benefited most consistently from playing video games. (Photo: Unsplash)

“There are some sociodemographic differences in what kinds of games people are playing,” Reynolds says, “and we wanted to account for that to isolate the differences that might arise from the gameplay itself.”

Increased processing speed

Spatial reasoning benefited most consistently from playing video games, with a significant effect measured in all three tests before and after adjustment for adolescent IQ, although the effect was about half as large after adjustment. There is also evidence that processing speed performance could increase after playing video games, as the results of one test remained significant even after adjustment. Working memory was the only domain that did not show evidence of improvement due to video game play, with non-significant numbers before and after adjustment.

Reynolds says that unimproved working memory results could be a consequence of the test used and the fact that only one test was used for this ability, compared to the three tests used for both processing speed and spatial reasoning.

“We can’t say a whole lot about working memory from one test,” he says. “In the future, we want to extend to other measures that would get more specifically at attention, working memory and other aspects of executive functioning.”

When video game play was broken down by the broad genre of game, there were some negative correlations: people who played Action+ games scored worse on processing speed, and those who played Puzzle+ games scored worse on spatial reasoning. However, these correlations were very small, and only statistically significant for one of the processing speed tests.

These results seem counterintuitive, which makes it particularly interesting to see if they will be replicated in other studies. As to benefits by genre, Action+ games had a particular association with spatial reasoning and Puzzle+ games had a particular association with processing speed.

According to the paper, the results for different tests may have been affected by how similar they are to video games. For example, with respect to spatial reasoning, Action+ gamers scored best on the Block Design test, which involves three-dimensional operations similar to those involved in playing many modern action games. By the same token, gamers may have performed worse on tests that were more divergent from video games due to their familiarity with related but substantially different tasks.

Future assessments

The researchers are currently collecting more data from the CATSLife sample, asking the same questions for further insight into how the observed effects change over the course of five or six years. “If people continue to play games, they’ll likely nominate newer games—it would be interesting to see if there is a long-standing influence or if new game play factors emerge,” Reynolds says.

Some changes could be made to the assessment of people’s gameplay to get more particular results. In the future, Reynolds says, “we would conduct more specific surveys of our participants: asking for more details about the games they play, the systems they use and how they approach gameplay. We asked questions that allowed us to get at the kinds of games they play, but not how they play them, and we’re making some inferences, so we’d want to dig deeper into that.”

“There has been some debate in the literature about the potential benefits or even detriments of video game play,” Reynolds explains, “but I think we found that, in a general sample that isn’t selected for pathological use or other characteristics related to playing video games, we found some salient, small positive effects.”

This brings up an important caveat, which is that even though there could be positive effects of playing video games, it is still possible to experience negative effects by engaging with them in a unhealthy manner. Because the positive effects are small, any negative effects due to playing video games irresponsibly, such as playing them for an excessive amount of time each day, are likely to outweigh the benefits.

“I think it will bear additional replication and future work,” Reynolds says, “but the benefits are quite interesting, and we’d like to see how this plays out with other kinds of activities as well.”

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91ɫ�� scientists find that playing video games comes with small but significant cognitive benefits.

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Is drought the new normal?

Rachel Sauer — Thu, 14 Aug 2025 17:56:36 +0000

Is drought the new normal? Rachel Sauer Thu, 08/14/2025 - 11:56

Pedro DiNezio and Timothy Shanahan

Climate models reveal how human activity may be locking the Southwest into permanent drought

A new wave of climate research is sounding a stark warning: Human activity may be driving drought more intensely—and more directly—than previously understood.

The southwestern United States has been in a historic megadrought for much of the past two decades, with its reservoirs including lakes Mead and Powell dipping to record lows and legal disputes erupting over rights to use water from the Colorado River.

This drought has been linked to the Pacific Decadal Oscillation, a climate pattern that swings between wet and dry phases every few decades. Since a phase change in the early 2000s, the region has endured a dry spell of epic proportions.

91ɫ�� scientist Pedro DiNezio, along with climate researchers around the world, assert that human activity may be driving drought more intensely—and more directly—than previously understood.

The PDO was thought to be a natural phenomenon, governed by unpredictable natural ocean and atmosphere fluctuations. But new research published in the journal Nature suggests that’s no longer the case.

Working with hundreds of climate model simulations, our team of atmosphere, earth and ocean scientists found that the PDO is now being strongly influenced by human factors and has been since the 1950s. It should have oscillated to a wetter phase by now, but instead it has been stuck. Our results suggest that drought could become the new normal for the region unless human-driven warming is halted.

The science of a drying world

For decades, scientists have relied on a basic physical principle to predict rainfall trends: Warmer air holds more moisture. In a warming world, this means wet areas are likely to get wetter, while dry regions become drier. In dry areas, as temperatures rise, more moisture is pulled from soils and transported away from these arid regions, intensifying droughts.

While most climate models simulate this general pattern, they often underestimate its full extent, particularly over land areas.

Yet countries are already experiencing drought emerging as one of the most immediate and severe consequences of climate change. Understanding what’s ahead is essential, to know how long these droughts will last and because severe droughts can have sweeping affects on ecosystems, economies and global food security.

Human fingerprints on megadroughts

Simulating rainfall is one of the greatest challenges in climate science. It depends on a complex interplay between large-scale wind patterns and small-scale processes such as cloud formation.

Until recently, climate models have not offered a clear picture of how rainfall patterns are likely to change in the near future as greenhouse gas emissions from vehicles, power plants and industries continue to heat up the planet. The models can diverge sharply in where, when and how precipitation will change. Even forecasts that average the results of several models differ when it comes to changes in rainfall patterns.

The techniques we deployed are helping to sharpen that picture for North America and across the tropics.

We looked back at the pattern of PDO phase changes over the past century using an exceptionally large ensemble of climate simulations. The massive number of simulations, more than 500, allowed us to isolate the human influences. This showed that the shifts in the PDO were driven by an interplay of increasing warming from greenhouse gas emissions and cooling from sun-blocking particles called aerosols that are associated with industrial pollution.

From the 1950s through the 1980s, we found that increasing aerosol emissions from rapid industrialization following World War II drove a positive trend in the PDO, making the Southwest rainier and less parched.

After the 1980s, we found that the combination of a sharp rise in greenhouse gas emissions from industries, power plants and vehicles and a reduction in aerosols as countries cleaned up their air pollution shifted the PDO into the negative, drought-generating trend that continues today.

This finding represents a paradigm shift in our scientific understanding of the PDO and a warning for the future. The current negative phase can no longer be seen as just a roll of the climate dice—it has been loaded by humans.

Our conclusion that global warming can drive the PDO into its negative, drought-inducing phase is also supported by geological records of past megadroughts. Around 6,000 years ago, during a period of high temperatures, evidence shows the emergence of a similar temperature pattern in the North Pacific and widespread drought across the Southwest.

Tropical drought risks underestimated

The past is also providing clues to future rainfall changes in the tropics and the risk of droughts in locations such as the Amazon.

One particularly instructive example comes from approximately 17,000 years ago. Geological evidence shows that there was a period of widespread rainfall shifts across the tropics coinciding with a major slowdown of ocean currents in the Atlantic.

These ocean currents, which play a crucial role in regulating global climate, naturally weakened or partially collapsed then, and they are expected to slow further this century at the current pace of global warming.

A recent study of that period, using computer models to analyze geologic evidence of earth’s climate history, found much stronger drying in the Amazon basin than previously understood. It also shows similar patterns of aridification in Central America, West Africa and Indonesia.

The results suggest that rainfall could decline precipitously again. Even a modest slowdown of a major Atlantic Ocean current could dry out rainforests, threaten vulnerable ecosystems and upend livelihoods across the tropics.

What comes next

Drought is a growing problem, increasingly driven by human influence. Confronting it will require rethinking water management, agricultural policy and adaptation strategies. Doing that well depends on predicting drought with far greater confidence.

Climate research shows that better predictions are possible by using computer models in new ways and rigorously validating their performance against evidence from past climate shifts. The picture that emerges is sobering, revealing a much higher risk of drought across the world.

Pedro DiNezio is an associate professor of atmospheric and oceanic sciences at the 91ɫ��. Timothy Shanahan is an associate professor of geological science at the University of Texas at Austin

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate models reveal how human activity may be locking the Southwest into permanent drought.

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It takes a village of mothers

Rachel Sauer — Wed, 13 Aug 2025 20:56:42 +0000

It takes a village of mothers Rachel Sauer Wed, 08/13/2025 - 14:56

Sona Dimidjian and Anahi Collado

How mothers supporting mothers can help fill the health care worker shortage gap and other barriers to care

For generations, women have relied on informal networks of friends, family and neighbors to navigate the complexities of birth and motherhood. Today, research is finally catching up to what generations of women have known: Peer support can be a lifeline.

Despite growing evidence, the unique wisdom and strength that arise when mothers help mothers has been surprisingly under‑explored in the scientific literature, but that’s beginning to change. Peer-delivered programs are beginning to bring together long-standing community traditions and structured, evidence-based approaches to support the mental health of new and expectant moms.

We are clinical psychologists at the 91ɫ�� Renée Crown Wellness Institute. Our work and research weaves together psychological science and the wisdom of mothers supporting mothers. Our program, Alma, supports women in restoring well-being in ways that are community-rooted, evidence-based and scalable.

Through the Alma program, researchers Sona Dimidjian (left) and Anahi Collado (right) aim to support women in restoring well-being in ways that are community-rooted, evidence-based and scalable.

Pressure on parents

Nearly 50% of parents report feeling overwhelmed by stress on most days. An even larger share, about 65%, experience feelings of loneliness, according to a 2024 report from the U.S. Department of Health and Human Services. These feelings hit mothers especially hard, the report says.

In 2025, mothers in the United States continue to shoulder most of the caregiving of children while also managing work, personal health and household responsibilities. The transition to motherhood is often marked by emotional and psychological strain. In fact, 10% to 20% of women experience depression during pregnancy, the postpartum period or both. Depression is one of the most common complications of childbirth. A similar number of women also face significant anxiety.

In many communities, mental health resources are scarce and stigma around mental health issues persists; therefore, many mothers are left to navigate such challenges alone and in silence. Antidepressants are widely prescribed, but research suggests that many women stop using antidepressants during pregnancy – yet they don’t start therapy or an alternative treatment instead.

Psychotherapy is the most preferred care option among new and expectant mothers, but it is often inaccessible or nonexistent. This is due in part to a workforce shortage of mental health providers.

The shortage has contributed to long wait times, geographic disparities and cultural and language barriers between providers and patients. This is especially true for underserved populations. In fact, more than 75% of depressed mothers do not receive the care they need.

Science of peer support

The science of peer support is part of a larger field exploring community health workers as one way to address the shortage of mental health providers. Peer mentors are trusted individuals from the community who share common experiences or challenges with those they serve. Through specialized training, they are equipped to deliver education, offer mental health support and connect people with needed resources.

A study that analyzed 30 randomized clinical trials involving individuals with serious mental illness found that peer support was associated with significant improvements in clinical outcomes and personal recovery. Researchers have proposed that peer support creates space for learning and healing, especially when peers share lived experience, culture and language.

In 2025, mothers in the United States continue to shoulder most of the caregiving of children while also managing work, personal health and household responsibilities. (Photo: Shutterstock)

As clinical psychologists, we heard from mothers in our work and communities that wanted to help other moms recover from depression, navigate the challenges of motherhood and avoid feeling alone. This insight led us to co-create Alma, a peer-led mental health program based on behavioral activation.

Behavioral activation is a proven method for treating depression based on decades of randomized clinical trials, including in new and expectant mothers. It helps new and expectant mothers reengage in meaningful activities to improve mood and functioning.

The Alma program

Alma is based on the principle that depression must be understood in context and that changing what you do can change how you feel. One strategy we use is to help a mother identify an activity that brings a sense of accomplishment, connection or enjoyment – and then take small steps to schedule that activity. Mothers might also be guided on ways to ask for help and strengthen their support networks. Alma is offered in English and Spanish.

Peer mentors typically meet with moms once a week for six to eight sessions. Sessions can take place in person or virtually, allowing flexibility that honors each family’s needs. Traditionally, peer mentors have been recruited through long-standing relationships with trusted community organizations and word-of-mouth referrals. This approach has helped ensure that mentors are deeply rooted in the communities they serve. Alma peer mentors are compensated for their time, which recognizes the value of their lived expertise, their training and the work involved in providing peer mentoring and support.

“This was the first time I felt like someone understood me, without me having to explain everything,” shared one mother during a post-program interview that all participants complete after finishing Alma.

To date, more than 700 mothers in Colorado have participated in Alma. In one of our studies, we focused on 126 Spanish-speaking Latina mothers who often face significant barriers to care, such as language differences, cost and stigma. For nearly 2 out of 3 mothers, symptoms of depression decreased enough to be considered a true, measurable recovery — not just a small change.

Notably, most of the depression improvement occurred within the first three Alma meetings. We also observed that peer mentors delivered the Alma program consistently and as intended. This suggests the program could be reliably expanded and replicated in other settings with similar positive outcomes.

A second study, conducted through a national survey of Spanish-speaking Latina new and expectant mothers, found that peer-led mental health support was not only perceived as effective, but also highly acceptable and deeply valued. Mothers noted that they were interested in peer-led support because it met them where they were: with language, trust and cultural understanding.

Supporting mothers works

Supporting mothers’ mental health is essential because it directly benefits both mothers and their children. Those improvements foster healthier emotional, cognitive and social development in their children. This interconnected impact highlights why investing in maternal mental health yields lasting benefits for the entire family.

It also makes strong economic sense to address mood and anxiety disorders among new and expectant mothers, which cost an estimated US$32,000 for each mother and child from conception through five years postpartum. More than half of those costs occur within the first year, driven primarily by productivity losses, preterm births and increased maternal health care needs.

Beyond the impact on individual families, the broader economic toll of untreated mood and anxiety disorders among new and expectant mothers is substantial. For example, it’s estimated that $4.7 billion a year are lost to mothers who have to miss work or reduce their job performance because of symptoms like fatigue, anxiety and depression.

Together – as individuals, families, communities and institutions – we can cultivate a world where the challenges of parenting are met with comprehensive support, allowing the joy of parenting to be fully realized. Because no one should have to do this alone.

Sona Dimidjian is director of the Renée Crown Wellness Institute and a professor of psychology and neuroscience at the 91ɫ��. Anahi Collado is a 91ɫ�� assistant research professor of psychology.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How mothers supporting mothers can help fill the health care worker shortage gap and other barriers to care.

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Raised with pets? Your immune system remembers

Rachel Sauer — Tue, 12 Aug 2025 16:46:30 +0000

Raised with pets? Your immune system remembers Rachel Sauer Tue, 08/12/2025 - 10:46

Cody DeBos

91ɫ�� researchers, with an international team of colleagues, find that childhood pets are linked to healthier stress responses

If you grew up in a city and without a pet, your immune system likely developed differently than that of someone who shared their childhood with a dog or cat. That difference, new research from 91ɫ�� Professor Christopher Lowry suggests, could influence how your body responds to stress even decades later.

In a study published in the journal Brain, Behavior, and Immunity, an international team of researchers, including Lowry and 91ɫ�� PhD student John Sterrett, found that for people raised in urban environments, having regular contact with pets early in life may protect against harmful immune responses to stress.

91ɫ�� scientist Christopher Lowry and his research colleagues found that having regular contact with pets early in life may protect against harmful immune responses to stress.

“Being raised in a home with pets can provide protection against chronic low-grade inflammation, which we know is a risk factor for stress-related psychiatric disorders and more,” Lowry says.

The study adds to a growing body of evidence that our childhood environments can leave a lasting mark on our physical and mental health.

Our oldest friends

Lowry is a professor in the Department of Integrative Physiology at 91ɫ�� and has spent much of his career studying how the microbial world interacts with the human brain. It’s a fascination that traces back to the 1990s when he started exploring how soil microbes influence mood.

“For about 25 years, we have been interested in understanding how microbes found in our environment—in nature, soil, fermenting vegetable matter, and unpurified water—can signal from the body to the brain,” Lowry says.

Along with a research team directed by Stafford Lightman at the University of Bristol’s University Research Center for Neuroendocrinology, Lowry studied Mycobacterium vaccae NCTC 11659 (M. vaccae), a microbe commonly found in soil.

His lab found that exposure to M. vaccae in mice activated serotonin pathways in the brain and produced antidepressant-like behavioral effects.

“M. vaccae is representative of diverse microbes in nature that have the ability to promote immunoregulation and protect us from inappropriate inflammation,” Lowry explains.

The microbe soon became a model for studying what scientists now call “Old Friends”—the microorganisms humans co-evolved with and depend on for proper immune system development.

“Being raised in a home with pets can provide protection against chronic low-grade inflammation, which we know is a risk factor for stress-related psychiatric disorders and more,” says 91ɫ�� researcher Christopher Lowry. (Photo: Bonnie Kittle/Unsplash)

It’s thought that modern urban living, with its clean indoor environments and reduced contact with naturally occurring microbes, disrupts this relationship. In turn, people living in such environments have experienced a rise in chronic, stress-related disorders.

Pets as microbial messengers

In a previous study, Lowry and his colleagues showed that people raised on farms, with regular exposure to animals, exhibited lower inflammatory responses to psychological stress. But in that study, it was hard to separate the effects of rural living from contact with animals.

So, the team designed a new study to answer a more specific question.

“We designed the study to determine if having pets in the home could protect against inappropriate inflammation in individuals raised in urban settings,” Lowry says.

The team recruited healthy adult men who had been raised in cities either with or without household pets. The participants were then exposed to the Trier Social Stress Test, and measurements of their immune function and inflammation were taken both before and after completing stressful tasks like public speaking.

Compared to their pet-free peers, individuals who grew up with pets showed a more balanced immune response and better regulation of stress-reactive cells.

But what accounts for this striking result?

“Exposures to ‘Old Friends,’ which are thought to increase in homes with pets, interacts with our immune system to produce more regulatory T cells,” Lowry explains. “Without sufficient exposure to ‘Old Friends’ we have reduced capacity to produce these regulatory T cells, which leads to inappropriate or unresolved inflammation.”

In short, a four-legged friend in the house means more microbial diversity. That might be just what your immune system needs to stay in balance.

Something as simple as living with a pet could help buffer the long-term health risks of urban living, notes 91ɫ�� researcher Christopher Lowry. (Photo: Helena Jankovičová Kováčová/Pexels)

From theory to therapy

Lowry and his team’s findings are just the beginning. He is now involved in several projects exploring how they could be applied in the real world.

“We are interested in exploring if we can increase mental health outcomes by increasing exposure to ‘Old Friends,’” he says, pointing to clinical trials testing microbial supplements and high-diversity plant-based beverages, which contain diverse microbial communities.

He’s also a co-founder of a 91ɫ�� startup company Kioga, which is developing soil-derived microbiome-based nutritional supplements, food ingredients and therapeutics. Their goal is to improve mental health outcomes for anyone experiencing high levels of perceived stress, whether or not they have a diagnosed disorder.

What comes next?

Lowry also notes that more research is needed to explore if the recent findings hold true for women or people of different ages or backgrounds.

“This is an extremely important question,” Lowry says. “More work is needed to fully understand the importance of upbringing in rural versus urban lifestyles in females.”

Still, the implications are clear. Something as simple as living with a pet could help buffer the long-term health risks of urban living. Given that more people than ever today live in cities and stress-related conditions are on the rise, Lowry’s work offers a hopeful solution.

“Humans co-evolved with these microbes in nature, and our body depends on them for a normally functioning immune system,” he says.

So, the next time you’re scrubbing muddy paw prints off the floor, remember that your four-legged friend is just trying to help you stay healthier in the long run.

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91ɫ�� scientist Christopher Lowry and research colleagues find that childhood pets are linked to healthier stress responses.

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Study: Using cannabis and psilocybin together may increase dependence

Rachel Sauer — Thu, 07 Aug 2025 18:16:17 +0000

Study: Using cannabis and psilocybin together may increase dependence Rachel Sauer Thu, 08/07/2025 - 12:16

Bradley Worrell

91ɫ�� researchers studied cannabis-psilocybin co-users and cannabis-only users to look for similarities and differences between the two groups, including drug-use motivations

In November 2022, Colorado voters approved Proposition 122, decriminalizing the personal use of mushrooms containing psilocybin, a psychedelic substance. That followed a decision by Colorado voters in 2014 to legalize recreational marijuana use.

Cannabis and psilocybin are becoming more commonly used, but there is still relatively little research on what happens when people use both, says Maddie Stanger, a 91ɫ�� Department of Psychology and Neuroscience researcher whose area of focus is motivations behind substance abuse and how people use substances to cope.

A recently published research paper co-authored by Stanger examined differences in cannabis dependence and reasons for using among individuals who regularly use marijuana and psilocybin versus marijuana-only users. In this case, co-use could either be the simultaneous use of cannabis and psilocybin or concurrent use over the same time period, Stanger explains.

Maddie Stanger is a 91ɫ�� Department of Psychology and Neuroscience researcher whose focus is motivations behind substance abuse and how people use substances to cope.

Stanger says this research is valuable because assessing individuals’ reasons for using substances can provide insight into potential harms, such as addiction or mental health issues. This is because motivations are related to quantity and frequency of use.

The researchers used a previous, larger study by the Center of Health and Neuroscience, Genes and Environment within the Department of Psychology and Neuroscience that investigated the effects of different cannabis strains on metabolic processes and insulin sensitivity.

From that study, researchers drew a test sample that included 97 regular cannabis users (those who used marijuana more than seven times a month) in Colorado. About a third of those had used psilocybin in the past three months while the rest had not. The researchers compared these two groups to understand how psilocybin use might affect marijuana use motives and dependencies.

Study participants were, on average, about 35 years old, mostly male and white, healthy overall and predominantly from the 91ɫ�� area, with at least some higher education. They reported using cannabis 21.73 out of the previous 30 days.

The motivations of all participants were measured using the Comprehensive Marijuana Motives Questionnaire (CMMQ), which encompasses 12 possible motives, including enjoyment, coping, experiment, boredom, celebration, altered perception, social anxiety, sleep and availability. Participants were also assessed for cannabis dependence based upon an 11-item Marijuana Dependence Scale (MDS) scoring system, which asks users to self-evaluate if they believe their cannabis use is excessive.

Considering motivation

Stanger says she and her research colleagues hypothesized that recent psilocybin users would have higher MDS scores and more strongly endorse coping, expansion (also referred to as “altered perception”) and enhancement/enjoyment motives compared with non-recent psilocybin users. Additionally, the researchers hypothesized that there would be correlations between dependence and coping motives for both groups, but that these would be stronger for recent psilocybin users relative to non-recent users.

The prediction that recent psilocybin users would have higher dependence scores than non-recent users was borne out, Stanger says. As expected, the research data demonstrated that psilocybin users showed mild signs of marijuana dependence, while non-psilocybin users did not, she says.

“Interestingly, we found that recent psilocybin users had indicated they were more likely to use for enjoyment, boredom and availability—and boredom and availability are shown in previous literature to be linked to increased cannabis problems and mental health symptoms.”

Additionally, compared to cannabis-only users, Stanger says the psilocybin co-user group exhibited higher scores on the motivations of enjoyment, boredom relief and availability/access, which can be indicative of dependency problems.

“Interestingly, we found that recent psilocybin users had indicated they were more likely to use for enjoyment, boredom and availability—and boredom and availability are shown in previous literature to be linked to increased cannabis problems and mental health symptoms,” she says.

However, contrary to the researchers’ hypothesis, Stanger says there was no difference in coping motives between the two groups.

The researchers note that these findings should be considered within the confines of the study limitations. Specifically, Stanger explains that the data came from a preexisting study and that this analysis was not the primary purpose of the larger project. Thus, there is no data on the dose of the psilocybin used and no information as to whether cannabis and psilocybin were used simultaneously versus concurrently. Additionally, the study ideally would have involved a more diverse group of participants, Stanger adds.

Still, Stanger says she believes the research is timely and valuable, as more states have followed Colorado since 2014 in legalizing marijuana sales for medicinal or recreational purposes, and it’s conceivable that states will follow the Centennial State in legalizing psilocybin in the coming years.

In addition to Stanger, co-authors of this paper include Professor Angela Bryan and Research Assistant Professor Carillon Skrzynski, both with the Department of Psychology and Neuroscience; and Researcher Harmony Soffer with the University of Colorado Anschutz Medical Center.

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91ɫ�� researchers studied cannabis-psilocybin co-users and cannabis-only users to look for similarities and differences between the two groups, including drug-use motivations.

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Medical issues and neighborhood opportunity can affect infant development

Rachel Sauer — Mon, 04 Aug 2025 20:21:30 +0000

Medical issues and neighborhood opportunity can affect infant development Rachel Sauer Mon, 08/04/2025 - 14:21

Sarah Kuta

91ɫ�� researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives

In an ideal world, every baby would be born perfectly healthy. Unfortunately, many newborns arrive prematurely or suffer from medical conditions that could hinder their future development.

Some of these high-risk infants live in neighborhoods with access to healthy food, low crime rates and affordable housing. Others, however, live in worse-off communities with limited access to quality education, health care, housing and jobs.

Now, new research led by 91ɫ��’s Emily Yeo explores how medical complexity and neighborhood opportunity might affect the development of high-risk infants.

Emily Yeo, a PhD student in the 91ɫ�� Department of Integrative Physiology, led research exploring how medical complexity and neighborhood opportunity might affect the development of high-risk infants.

The findings, recently published in the Journal of Pediatrics, suggest some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.

“What the study highlights is that there’s sort of a double burden on medically complex infants living in lower-opportunity neighborhoods,” says Yeo, a doctoral student in the Department of Integrative Physiology. “There needs to be a lot more research into how we can better support these infants, especially within the first couple of years of their lives, which are critical for development and when small interventions could have a huge, life-long impact.”

Studying high-risk infants in California

Public health professionals have long understood that social, environmental and economic factors affect human health and development. Everything from a person’s income and education levels to the purity of the air they breathe and their access to grocery stores can play a role in their well-being.

Against this backdrop, scientists wanted to understand whether there was a relationship between the complexity of infants’ medical conditions, their neighborhood opportunity and their developmental progress.

“To fully understand the developmental challenges these infants face, it is essential to consider how their medical conditions interact with the social and environmental contexts of their upbringing,” says Yeo.

The team studied 440 infants born in Southern California between 2014 and 2023. Doctors had deemed these babies “high-risk” because they were born prematurely, had very low birth weights or suffered from conditions that required treatment in a neonatal intensive care unit.

By reviewing the infants’ medical records, scientists were able to categorize them based on the seriousness of their situation. Infants with the highest level of medical complexity, for instance, had conditions like permanent brain damage or chronic respiratory issues. Those with the lowest level of medical complexity, meanwhile, had more easily treatable conditions, like acute lung or eye infections.

Researchers also assessed each child’s neighborhood opportunity level, based on their home address. For this, they turned to the Child Opportunity Index, a pre-existing, composite index that analyzes education, health, social and economic data from every census tract in the United States.

Some neighborhoods earn high scores, because the children who live there have access to quality schools, clean air, health care, playgrounds and other conditions that will help them grow up healthy and become thriving adults. Other neighborhoods, however, offer very few or none of these resources. Black, Hispanic and Native American children are more likely to live in very low-opportunity neighborhoods compared to their White peers.

For each child, researchers also collected developmental scores from standard tests conducted when they were between the ages of 4 months and 36 months old. The scores came from the Bayley Scales of Infant and Toddler Development, which doctors consider the “gold standard” for evaluating infant cognitive, motor and language skills, the researchers write in the paper.

91ɫ�� researcher Emily Yeo found that childhood development is affected by both medical and social factors, which aligns with what pediatricians see in daily practice. (Photo: Emily May/Unsplash)

When the scientists analyzed all of the data they had gathered, some clear patterns began to emerge. Developmental scores got worse as medical complexity increased, meaning that infants with more severe and complicated health conditions had lower cognitive, motor and language scores. These finding are consistent with previous studies, says Yeo, which have found that infants with fewer medical complications are also likely to face fewer challenges achieving growth milestones.

The study also found that medical complexity had a more significant effect on developmental outcomes than gestational age, or how early a baby was born. This is an important takeaway for pediatricians, who have long used gestational age to predict potential developmental delays or issues, says Yeo.

“Gestational age might be useful for infants who are not medically complex, but if you’re looking specifically at those infants, we need a more granular tool,” she says. “With this group of infants, we saw that gestational age didn’t really play a huge role in deciphering differences in development, whereas their degree of medical complexity did.”

The researchers also found a correlation between lower neighborhood opportunity scores and decreased language scores, but not cognitive and motor scores. The reasons for this discrepancy are not clear. But, overall, this finding indicates that where an infant lives does seem to play a role in their development.

Importantly, the study also ruled out differences in development based on race and ethnicity alone. Black and Hispanic babies did have lower developmental scores than White babies, but the findings indicate those disparities resulted from differences in the infants’ socio-demographic and medical factors.

“The differences do not come from race and ethnicity itself—they come from other influential factors that tend to be worse in those groups,” says Yeo, adding that this finding aligns with the general shift from race-based to race-conscious medicine.

More social supports for development

Together, the study results align with what pediatricians see in real life—that childhood development is affected by both medical and social factors. The research also highlights the importance of early intervention programs and policies designed to help children succeed.

“It’s one more indication of how, if we really want to move the needle and improve the outcomes of these babies that are born with medical risk factors, we need to put as many social supports in place as we can to support their development,” says study senior author Christine Mirzaian, a pediatrician at Children’s Hospital Los Angeles and an associate professor of clinical pediatrics in the Keck School of Medicine at the University of Southern California.

“It’s not just the child’s medical diagnosis that is going to impact their development—it’s also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.”

The study did not explore the possible mechanisms at play—that is, why medical complexity and neighborhood opportunity seem to be linked with development. But the researchers have a few theories.

For one, children with very serious health issues often need to use medical equipment that helps them breathe and eat—like feeding tubes in their stomachs or oxygen tubes in their noses. From a purely physical standpoint, these devices may make it difficult for infants to do “all the basic things babies do,” Mirzaian says, like rolling around or pulling themselves up to a standing position.

Another possible explanation is that a child’s appointments and treatments may leave little time for activities that promote development, like reading and playing with toys, Mirzaian adds.

Families living in neighborhoods with low opportunity scores, meanwhile, may be grappling with poverty—and having a baby with a serious medical condition likely only adds to their stress. Through no fault of their own, caregivers may need to focus more on basic needs—like how they’re going to pay next month’s rent or put food on the table—and less on their child’s development, says Mirzaian.

‘Medical Data Alone Does Not Tell the Whole Story’

Looking ahead, the co-authors hope other researchers will repeat and replicate the study, perhaps in other geographic locations or with slightly different populations. Future work might also involve following the same children as they grow up, to see whether and how their developmental outcomes change over time.

For now, though, the study is a good first step toward understanding the link between medical complexity, neighborhood opportunity and development. Zooming out, the findings also reinforce the idea that “medical data alone does not tell the whole story,” says Yeo.

“It’s important for researchers to consider social explanations to formulate a holistic picture of infant development,” she adds. “It’s not just the child’s medical diagnosis that is going to impact their development—it’s also the neighborhood the child is brought up in, how much medical care their family is able to afford and other barriers.”

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91ɫ�� researcher Emily Yeo finds that some babies may benefit from more support and resources so they can grow up to lead long, happy and healthy lives.

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Top photo: Philip Mroz/Unsplash

Cycling tradition meets biomechanics at CU

Rachel Sauer — Thu, 31 Jul 2025 18:47:46 +0000

Cycling tradition meets biomechanics at CU Rachel Sauer Thu, 07/31/2025 - 12:47

Cody DeBos

In time for Buffalo Bicycle Classic, 91ɫ�� researchers challenge cycling norms that stiff cycling-shoe soles are essential for efficient riding

Years ago, Rodger Kram, a biomechanics researcher and now 91ɫ�� associate professor emeritus of integrative physiology, offered a student in his lab a challenge.

Asher Straw, a sophomore at the time and an avid cyclist, was convinced that stiff, carbon fiber soles were essential for serious riders because they made for more efficient pedaling. Kram, with a twinkle in his eye, disagreed.

“I provocatively said that I didn’t think they made any difference,” Kram recalls. “I figured even very flexible running shoes would be just as efficient as carbon fiber cycling shoes when riding at a steady pace and moderate intensity.”

Rodger Kram is a biomechanics researcher and 91ɫ�� associate professor emeritus of integrative physiology.

Straw was determined to prove his professor wrong. So, the two set out on a small but illuminating study and found that ultra-stiff shoes didn’t offer improved efficiency during moderate cycling.

But that was just the beginning.

Kram and his students have since spent nearly a decade exploring a deceptively simple question: How stiff does a cycling shoe really need to be?

The answer, it turns out, may surprise even the most gear-obsessed riders.

The stiffness myth

Carbon fiber shoes have been marketed as the gold standard for years, and riders have adopted the message. These shoes are sleek and featherlight, and their unyielding soles allegedly transfer more power from leg to pedal.

Kram’s research team, including then-graduate student Tripp Hurt, conducted a study to test the limits of this belief. They equipped trained cyclists with a set of three identical shoes, each fitted with a unique sole material of varying stiffness. The cyclists were then asked to sprint as hard as possible up a 50-meter stretch of road in each pair.

After multiple experiments, the researchers had their answer.

“There was a breakpoint,” Kram says. “Below a certain stiffness, sprint performance does trail off.”

But not by much. Going from nylon soles (a very stiff reference) to a medium-stiff TPU (thermoplastic polyurethane) sole caused only a 3.1% drop in maximal one-second power output. The more flexible, soft TPU sole yielded a further power-output decrease of just 2.4%. At those levels, most cyclists wouldn’t notice the difference.

“The $150 shoes were just as good as the $450 shoes,” Kram says.

Comfort over carbon

“For most of us, like riders in the Buffalo Bicycle Classic, there are far more important qualities in a shoe beyond sprint performance. Are they comfortable would be number one. Do they fit your foot?” Kram asks, adding that when picking out new shoes, “sole stiffness should be way down your list.”

“For most of us, like riders in the Buffalo Bicycle Classic, there are far more important qualities in a shoe beyond sprint performance. Are they comfortable would be number one. Do they fit your foot?” asks researcher Rodger Kram. (Photo: Wikimedia Commons)

It’s a refreshing perspective in a world where the latest (and often most expensive) iterations are always advertised the loudest. Stiff soles may seem impressive in an ad, but they aren’t always practical, Kram says. They can even be a hazard.

“Social riders often stop for a snack or coffee, and it’s easy to fall when trying to walk in carbon fiber soles on the tile floor of a café,” Kram says.

There’s also a growing awareness of carbon fiber’s environmental toll. Making carbon fiber is energy intensive and expensive, and the end product is nearly impossible to recycle. Though the sole of a cycling shoe isn’t world-ending, the cumulative effect of our consumption habits adds up.

If riders are sacrificing comfort, affordability and sustainability for just a few watts of power they may never use, Kram wonders, what’s the point?

Lab to innovation

That question stuck with Tripp Hurt, the aforementioned 91ɫ�� graduate. Inspired by the science, he found Brevay, a shoe startup based in Seattle.

“I had my ‘lightbulb’ moment after a night out with friends,” Hurt says. “I started to think about my biomechanics research and how it was relevant to the overall cycling market. We see these results, but nothing has changed about the way cycling companies were building their product.”

So, Hurt decided to build a new kind of shoe. Brevay’s first model, the Road One, will be a high-performance road cycling shoe made from sustainable materials.

“Sustainability and performance are the north star for Brevay. We’re the first brand developing a sustainable cycling shoe, so the market is unproven if this is a category that cyclists are interested in. But we’re building it anyway,” Hurt says.

This year, Rodger Kram will work at the Buffalo Bicycle Classic aid station near his home in Ward, handing out water and snacks to the riders. Though he’s retired from teaching, he nevertheless considers it important to help make CU Bulder affordable for the next generation of curious students.

That means sourcing bio-based materials, investing in an alternative supply chain and pricing the shoes competitively with the high-end carbon-fiber models they aim to replace.

Challenging assumptions

For Kram, the research is about more than shoes.

“We love challenging conventional wisdom,” he says, “and cycling is a sport fraught with tradition.”

That spirit of inquiry is part of what makes 91ɫ��’s research culture special, he adds. The study, and its illuminating results, started with a student’s curiosity and a professor’s willingness to be proven wrong.

“It represented a major shift in my career trajectory,” Hurt says of his time in Kram’s lab. “I felt more at home working on running and cycling biomechanics.”

As elite athletes continue to chase fractions of a second, Kram and Hurt hope their work encourages others to rethink what performance really means.

For many, like riders tackling 91ɫ�� Canyon to fundraise for scholarships in the Buffalo Bicycle Classic, choosing the right shoe shouldn’t be about speed, Kram says, but about enjoying the ride, staying comfortable and being mindful of the environment.

In the end, as Kram puts it, “there are far more important qualities in a cycling shoe than sprint performance.”

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In time for Buffalo Bicycle Classic, 91ɫ�� researchers challenge cycling norms that stiff cycling-shoe soles are essential for efficient riding.

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