A comprehensive new study published in The Lancet provides a global assessment of road traffic injuries from 1990 to 2023.
Analysing data across 204 countries and various income groups, researchers found that while global mortality and incidence rates have generally decreased, progress is dangerously uneven and heavily influenced by a nation’s wealth. Low-income countries face a death rate nearly six times higher than high-income nations, despite often having lower overall case numbers. The report identifies road injuries as the leading cause of death for males aged 10–39, highlighting a major public health crisis for young people. Beyond fatalities, the study quantifies the massive burden of long-term disability, frequently caused by severe head injuries and fractures. A separate study in South African Family Practice explored the local challenges in reducing road traffic mortality.
Ultimately, the authors argue that meeting international safety targets requires urgent structural reform and significantly increased investment in poorer regions.
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Compression wraps are unlikely to help venous leg ulcers heal faster than standard compression treatments, according to a clinical trial led by University of Manchester and York researchers.
The findings of the study, funded by the National Institute of Health and Care Research (NIHR) suggest the wraps may not be the best first-line option for patients receiving strong compression therapy.
Venous leg ulcers affect thousands of people and can take months to heal, causing pain, reduced mobility and a significant burden on healthcare services.
Strong compression is an important treatment for people with venous leg ulcers, to improve blood flow in the lower leg and support healing.
It can be provided in different ways, including bandages systems that can have two or four layers, compression stockings that have two layers and adjustable compression wraps that fasten around the leg with Velcro-style straps.
All these compression approaches aim to deliver the same level of compression but differ in how they are applied, how easy they are to use and how comfortable people find them.
Wraps have become increasingly popular because they can be adjusted and, in some cases, self-applied by people with leg ulcers or those around them. However, there has been limited high-quality evidence comparing compression wraps with other commonly used strong compression treatments.
The researchers carried out a large randomised controlled trial involving 637 adults receiving care at 33 mainly community sites across the UK.
Participants were assigned to be offered either compression wraps, two-layer compression bandages, or established evidence-based compression treatments (four-layer bandages or two-layer compression stockings).
The researchers found that ulcers healed more slowly in patients offered compression wraps than in those offered established evidence-based compression treatments.
Patients receiving compression wraps also appeared to heal more slowly than those treated with two-layer compression bandages, although this difference was not statistically significant.
The study found that two-layer compression bandages performed similarly to established evidence-based compression treatments.
The findings provide some of the strongest evidence to date comparing commonly used compression therapies for venous leg ulcers.
A separate companion process evaluation found patients liked compression wraps because they were comfortable, easy to adjust, and could be removed for showering,
However, these same features may also mean that people are more likely to loosen or remove the wraps, potentially reducing the amount of therapeutic compression delivered and helping explain the slower healing observed in the trial.
Together, the studies suggest compression wraps should not routinely be the first choice for most people with venous leg ulcers.
However, they may still be appropriate for some patients where comfort, independence or self-management are particularly important, provided patients receive clear advice on maintaining effective compression.
Jo Dumville, Professor of Applied Health Research from the University of Manchester said: “Venous leg ulcers can have a major impact people’s quality of life and place a significant burden on healthcare services, so it is important that health professionals have robust evidence to guide treatment decisions”.
“Our study compared three commonly used strong compression approaches in a real-world NHS setting and suggested that that compression wraps do not improve healing times when compared with established evidence-based treatments.”
Catherine Arundel, Senior Research Fellow at the University of York said: “While some uncertainty remains, these findings suggest that compression wraps are unlikely to offer a healing advantage as a first-line treatment”.
“The results will help clinicians, patients and healthcare providers make informed decisions about the most appropriate therapies for managing venous leg ulcers.”
The paper Compression therapies for venous leg ulcers: The VENous Ulcer Study 6 (VenUS 6), an open, multicentre, randomised clinical trial is published in PLOS Medicine https://doi.org/10.1371/journal.pmed.1005154
The companion process evaluation Compression therapies for the treatment of venous leg ulcers: a mixed method process evaluation in a randomised controlled trial, VenUS6 is published in Trials https://doi.org/10.1186/s13063-023-07681-7
For patients suffering from traumatic injuries that leave behind volumetric gaps – where significant bone and blood vessels are lost – the clock is always ticking. Without a nearby blood supply, cells in the centre of a large injury cannot survive, often leading to permanent tissue loss or failed grafts.
A team of eight scientists at The University of Texas at San Antonio has discovered a potential ‘perfect recipe’ to address this challenge. By blending two natural proteins found in the human body, the researchers created a specialised scaffold that allows bone and blood vessels to grow simultaneously at an accelerated rate.
The study, published in the journal Biomaterials Advances, identifies a 50:50 ratio of collagen and fibrin as the ideal environment for tissue repair.
The Lego blocks of healing
The technology relies on what scientists call interpenetrating polymer networks, or IPNs. In simpler terms, it is a microscopic support structure where different materials are entangled to create a stable foundation for new growth.
“An IPN network is two things that are entangled like a giant mess of Legos,” said Teja Guda, PhD, the Jacobson Distinguished Professor of Innovation and Entrepreneurship in the Department of Biomedical Engineering and Chemical Engineering at UT San Antonio and the study’s corresponding author. “We are leaving all the building blocks there and letting the cells build whatever Lego structure they like the most.”
In this biological ‘Lego’ set, one material is fibrin, the protein the body uses to form blood clots immediately after an injury. The other is collagen, the primary structural protein found in bones and other tissues.
Seeding the scaffold with MVFs and MSCs
To turn these protein gels into living tissue, the research team “seeded” the hydrogels with two critical types of biological starters: microvascular fragments (MVFs) and mesenchymal stem cells (MSCs). The MVFs have the capacity to grow into blood vessels, while the MSCs can, with the right environmental cues, grow into bone.
The researchers integrated these components by mixing the living MVFs and MSCs directly into the liquid protein solution before it underwent gelation. This 3D encapsulation ensured the cells were suspended throughout the entire depth of the scaffold rather than just sitting on the surface.
Balancing blood and bone
Standard medical treatments for severe bone loss typically involve autografts, where bone is harvested from another part of the patient’s body, or allografts, which use processed bone from a donor. These traditional grafts often fail to integrate because they lack an immediate blood supply to nourish the new tissue. Without rapid vascularisation, the transplanted bone can become necrotic, leading to a high rate of clinical failure in complex trauma cases.
The challenge for UT San Antonio researchers was finding the right balance between the two proteins to support both blood vessel and bone regeneration. Fibrin is excellent at recruiting the cells needed to form blood vessels, a process called angiogenesis. Collagen provides the mechanical strength needed to guide the development of bone, or osteogenesis.
“Whenever you have an injury where you are losing volume, you not only lose the tissue itself, but you’re also losing blood vasculature,” said Gennifer Chiou, a postdoctoral fellow at UT San Antonio and the study’s lead author. “We’re looking at how we can regenerate both the tissue and the vessel itself within specifically bone tissue.”
The team tested five different ratios of the two proteins. They found that while gels with more fibrin supported faster vessel sprouting, they lacked the stability needed for long-term bone growth. Conversely, high-collagen gels were too stiff for vessels to penetrate easily.
The 50:50 blend struck an ideal balance. The MVFs were able to sprout and branch out into a robust, interconnected network. Simultaneously, the MSCs developed in a stable environment, expressing the specific genetic markers needed to mature into bone-forming cells. This dual-growth approach ensures that as the new bone forms, it is continuously supplied with the blood and nutrients it needs to remain viable.
From the lab to the clinic
Because the materials used in the study – collagen, fibrin and the patient’s own blood vessels – are all naturally occurring in the body, the researchers believe the technology faces fewer regulatory hurdles than synthetic alternatives.
“There is almost nothing new in our material,” Guda said. “It’s your collagen, it’s your blood vessels, it’s your fibrin. The end goal is to provide evidence that will guide how clinicians think about healing wounds.”
The team hopes to proceed to preclinical trials in the near future, which will provide further support for the treatment to one day become standard practice.
High doses of intravenous (IV) vitamin C may lower the risks of death and sepsis in trauma patients, as well as shortening hospital stay, suggests a review of the available evidence published online in the journal BMJ Military Health.
Although its effects are biologically plausible, especially given its role in aiding tissue repair and recovery, among other things, the quality of the available evidence isn’t currently good enough to recommend the use of vitamin C in trauma patients, say the researchers.
Major trauma triggers a complex physiological response in those affected and carries a high risk of death. And vitamin C, which helps to boost blood pressure, regulate the vital interface between blood and tissues (endothelial function), and neutralise harmful free radicals, is rapidly depleted in critical illness, explain the researchers.
As such, vitamin C has been mooted as a potentially promising treatment to aid the recovery of trauma patients, including in the context of the war in Ukraine. But this approach is yet to be rigorously reviewed or formally implemented, they add.
In a bid to extend the evidence base, the researchers scoured research databases for relevant published studies on high dose IV vitamin C, published up to the end of 2025.
They focused on its impact on death within 30 days of hospital discharge; prognostic scoring systems (Apache II, SOFA); incidence of complications, including sepsis and organ failure; and length of hospital stay.
Out of an initial haul of 108 studies, six, involving a total of 5171 patients, were eligible for systematic review. Three studies were randomised controlled clinical trials; 3 were observational studies.
The included studies reported a significant reduction in 30 day mortality, with significantly shorter intensive care unit and hospital stays. And 4 studies showed lower rates of sepsis in patients receiving vitamin C; 2 found lower rates of multi-organ failure.
“Overall, our findings demonstrate evidence of possible benefit in using high-dose vitamin C in the management of trauma patients,” but the variation in the reported effects “suggests that treatment effects may be context-dependent rather than generalisable across all critical illnesses,” write the researchers.
And they highlight several limitations to their findings: namely, the small number of studies, half of which were observational; and differences in patient groups, methodology, dosing regimens, co-interventions and outcome reporting.
“As our included studies did not use IV vitamin C monotherapy, we cannot truly associate our results with vitamin C alone. No studies investigated the timing of vitamin C, and therefore the optimal timing to administer vitamin C remains unclear.
“These methodological constraints limit the ability to draw firm conclusions about the optimal treatment protocols to use the potential benefits of vitamin C and contribute to the low certainty of evidence identified in this review,” they add.
But they suggest: “Even slight reductions in mortality, sepsis, organ failure or critical care requirement could be used to consider its use in current operational settings, providing a clear rationale for future trauma-specific research before clinical adoption.”
Study shows that mechanical contraction by an app-controlled electrical device enhances wound healing
Application demonstration of MSWZ. (a) The flexible MCU of MSWZ integrates BLE communication and can be controlled by mobile terminal applications. (b) The core components of MSWZ and its manipulation logic. (c) MSWZ can work stably in high-strain areas such as wrist joints. (d) The MSWZ maintains a seamless fit to the skin. (e) The MSWZ achieves programmable mechanical contraction against human skin tension. Source: Cai et al., Advanced Science, 2026.
Skin is our protective barrier from the outside world, and it is highly susceptible to damage. To prevent infection, restore protective skin cells, and reduce scarring, it is essential to quickly and robustly close a wound. A new study, published by Wiley in Advanced Science, showed that a multi-axis stretchable wound zipper (MSWZ) is effective in closing complex wounds quickly, improving wound healing. The MSWZ uses programmable force that can be personalised via mobile application, enhancing patient comfort and compliance.
Current conventional approaches, such as sutures, cannot adapt to complex wound shapes and require healthcare professionals for their application. New alternatives, like temperature-responsive contractile dressings, are promising, yet can be unpredictable, compromised by environmental factors, and insufficient in their force to close a wound. Flexible bioelectronic systems enable precise control of mechanical contraction, though they have not yet been used in wound healing.
To utilise flexible bioelectronic systems for wound healing, researchers designed the MSWZ. The MSWZ is made up of a mechanical metamaterial in a lattice structure that shrinks and responds like human skin, a reliable conductive layer, and a breathable, flexible encapsulation material. Biocompatible and comfortable, the MSWZ stretches in six directions to accommodate complex wound morphologies, is wearable even on high-strain areas of the skin, and can be controlled through an app.
In rats, the pre-stretched MSWZ outperformed surgical suturing in the repair of linear wounds. For circular wounds, the pre-stretched MSWZ restored the epithelial barrier, decreased the wound width, and enhanced reconstruction of the collagen matrix. The MSWZ was effective in healing spindle- and oval-shaped wounds, which are most common in the clinic. Using immunohistochemistry, the researchers showed that pre-stretched MSWZ promotes blood flow to supply energy and nutrients for wound healing and supports matrix remodeling to reduce scar formation.
These findings suggest that the MSWZ enables rapid and robust wound healing at a molecular level. The MSWZ is easy to use, personalized, and programmable, adapting to complex wound types and the patient’s comfort level.
“Traditional wound closure methods, such as sutures or skin staples, not only contract in a single direction—making them unsuitable for complex wound shapes—but also fail to allow for quantification of the applied closure force. Our novel ‘multi-axis stretchable zipper’ addresses these limitations. Constructed from shape-memory alloy metamaterials, it can freely stretch in six directions to conform to any complex wound and enables precise, programmable mechanical contraction via a smartphone. We believe this technology offers an innovative solution for future wound care, ultimately alleviating patient suffering and significantly accelerating the healing process,” said senior author Yiming Zhang, PhD, of Xinqiao Hospital at Army Medical University in Chongqing, China.
Additional information NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com
Full Citation: “Multi-axis stretchable zippers for personalized wound healing.” Siyuan Cai, Guang Yao, Zijian Chen, Shiqi Zhou, Peisi Li, Liheng Lin, Huake Yang, Ziyi Zhou, Linbo Jin, Xingyi Gan, Chenzheng Zhou, Zhen Cai, Taisong Pan, Min Gao, Dongli Fan, Yuan Lin, and Yiming Zhang. Advanced Science; Published Online: June 11, 2026 (DOI: 10.1002/advs.75744). URL: http://doi.wiley.com/10.1002/advs.75744
Researchers at the Terasaki Institute for Biomedical Innovation and University of Arizona College of Medicine, have developed a topical gel formulation with 4-aminopyridine (4-AP) to treat burn wounds, achieving near-complete closure in 21 days. The findings are published in the journal Biomaterials.
Burn injuries rank among the most difficult wounds to heal. The current gold standard, transplanting skin from a donor site on the patient’s own body, is limited by donor site morbidity and the need for large amounts of healthy tissue. This research offers a non-invasive alternative: a laponite-gelatin gel that delivers 4-AP directly to the wound, concentrating the drug where it is needed rather than exposing the whole body to it. Prolonged systemic use of 4-AP can cause serious side effects, including seizures, making localised delivery a critical advance.
The drug is best known under the brand name Ampyra for treating multiple sclerosis. Earlier work showed it could influence keratinocytes and fibroblasts: the two cell types central to skin repair, but systemic administration carried unacceptable risks. Embedding it in a gel resolves that problem while preserving its therapeutic potential.
“By delivering 4-AP directly to the wound site, we harness its regenerative potential while avoiding the systemic risks that have limited its use. We believe this approach could meaningfully change how burn injuries are managed clinically,” said Dr. Johnson V. John, Assistant Professor at the Terasaki Institute for Biomedical Innovation
Laboratory tests confirmed that the gel releases 4-AP at a controlled rate, is compatible with living cells, and produces more than 90% wound closure within 48 hours. In animal studies, treated wounds closed faster than controls starting at day six, reaching near-complete closure by day 21, while control wounds remained partially open. Tissue analysis showed the gel reduced inflammation, promoted re-epithelialisation and angiogenesis, and drove fibroblast-to-myofibroblast transformation. Collagen deposition increased markedly by 438% for type I and 288 percent for type III versus controls (P < 0.05 to P < 0.0002), with an improved collagen ratio signalling better-quality tissue maturation.
Because 4-AP is already FDA-approved with a well-characterised safety profile, this repurposing strategy could accelerate the path to clinical trials compared with developing an entirely new compound from scratch.
“This research exemplifies our commitment to reimagining existing therapies to address medicine’s most persistent challenges. We look forward to seeing it advance toward clinical application,” stated Xiling Shen, Acting Director of the Terasaki Institute for Biomedical Innovation.
Giving whole blood or the component parts of blood are equally effective options for paramedics and emergency medical technicians to use in treating patients with severe, traumatic bleeding before arriving at the hospital, according to a large, nationwide trial directed by University of Pittsburgh and UPMC clinicians and scientists.
The results, published in the New England Journal of Medicine, provide flexibility to prehospital emergency care providers and could increase the odds that traumatically injured patients receive blood as soon as possible.
“Traumatic bleeding is the leading cause of trauma death and is the most time-sensitive injury a person could suffer æ more time sensitive than a stroke or heart attack,” said co-lead author Jason Sperry, professor of surgery in Pitt’s School of Medicine, and chief of trauma surgery at UPMC. “But it is preventable – and that starts with giving blood back to the injured person before they even arrive at the hospital.”
Donated blood is usually separated into parts – red cells, plasma and platelets – for storage and so the parts can be used individually as needed. When someone is bleeding, emergency clinicians will often give all or some of these parts to the patient at once. Giving either whole blood or its component parts had long been considered safe options.
But which is better for treating severe bleeding: Giving never-separated whole blood or giving the components? The answer matters for blood bank and emergency care logistics.
The multicentre trial, which ran from May 2022 to June 2025, enrolled and included 1020 severely bleeding patients who were transferred to a trauma centre by medical helicopter. The patients were randomised 2-to-1 to receive either whole blood or blood components.
The research team found no statistically significant difference between the two study arms. In both cases about a fifth to a quarter of the patients died within 30 days, compared to a third of traumatically bleeding patients who do not receive blood before arriving at the hospital.
“This is good news,” said co-lead author Guyette, who is also medical director of STAT MedEvac, which is directed by a consortium of UPMC hospitals and is the nation’s largest academic, nonprofit critical care transport group. “It means that emergency responders can use whatever form of blood is most accessible to them. In U.S. civilian emergencies that may be component blood because that is how most blood banks package it, but in military settings whole blood is often all that is available. We’ve shown that both are equally great options.”
In March, a European group announced the results of a similar, slightly smaller trial conducted in England, also published in the New England Journal of Medicine. Like the Pittsburgh team, they also found that giving whole blood or blood components was equally effective. The clinician-researchers believe that the combined findings will be reflected in guidelines set by various societies that oversee trauma care, surgery and blood handling.
Whole blood is good for 21 days after donation, so the clinician-scientists were also curious if patient outcomes were any different if they were given new blood or blood closer to the expiration date. They learned that it made no difference—outcomes were the same for patients receiving newer blood within 14 days of donation compared to those receiving older blood within seven days of expiration.
“Our thoughtful approach to the study design allowed us to not only answer the important question of the efficacy of whole blood compared to component therapy, but also to evaluate the health impact of an important public health question, the age of whole blood,” said senior author Wisniewski, who is also codirector of the Epidemiology Data Center at Pitt’s School of Public Health. “Our trial provides reassurance by verifying current standards that support the use of whole blood units throughout their entire shelf life.”
The team also noted that the findings wouldn’t have been possible without the generosity of blood donors, study participants agreeing to share their data and the hard work of emergency care providers.
“We’re very grateful to everyone involved, particularly the paramedics, emergency medical technicians and flight nurses,” Guyette said. “We are hopeful that this study and future research will give them better tools to save lives.”
Researchers at McGill University have developed a rapid way to engineer blood clots that stop severe bleeding and support tissue healing more effectively. Their technique, called “click clotting,” links red blood cell surface proteins through a chemical reaction, resulting in a biocompatible clot that is 13 times more resistant to fracturing and four times more adhesive than natural blood clots. The team said the method, described in Nature, could be used to develop life-saving biomaterials to help control severe bleeding, as well as benefit people with clotting disorders.
“Natural blood clots can be slow to form and mechanically fragile, which limits their ability to stop severe bleeding and can compromise healing,” said Jianyu Li, senior author and Professor of Mechanical Engineering and Canada Research Chair in Tissue Repair and Regeneration. “Our work shows that, when engineered appropriately, red blood cells can play a central structural role, enabling the design of stronger and more functional biomaterials.”
Shuaibing Jiang led the research during his PhD studies at McGill. He is now a Postdoctoral Associate at Mass General Brigham and Women’s Hospital, Harvard Medical School.
Researchers at the University of British Columbia, the Medical College of Wisconsin, the University of Colorado Boulder, the University of Toronto, and the Versiti Blood Research Institute also contributed.
Connected by chemical reaction
Previous efforts to crosslink red blood cells used chitosan, a polymer derived from crustacean shells, but these led to brittle clots, ruptured cells and inconsistent clotting. In “click clotting,” the clot structure is fundamentally strengthened through a fast, bio-safe chemical reaction that connects proteins on the red blood cell surface, forming a solid gel in just five seconds.
Because the “click” reaction doesn’t interfere with normal blood chemistry, it can work alongside the body’s natural clotting process. As a result, the artificial cell‑based gel, called a “cytogel,” can be added to whole blood, where it becomes embedded within the body’s own fibrin clot.
“The technology enables both autologous clots (using the patient’s own blood) and allogeneic clots (using type-matched donor blood). Autologous clots can be prepared in approximately 20 minutes, while allogeneic clots can be prepared within about 10 minutes. Given typical clinical time constraints, this approach has strong potential for in-patient emergency care, wound management and related settings,” Li said.
The results were confirmed through in vitro testing, as well as by testing on rodents. A highlight was the effective healing and regeneration observed in the injured liver, with performance exceeding that of the clinically used product tested in this study. Analysis showed minimal evidence of immune reactivity and no toxicity in major organs.
Further research required
The researchers say that while further study is required before the cytogel can be used in clinical settings, the research establishes a foundation for its design and application.
“Engineered blood clots have strong potential for broad clinical use and could improve outcomes across many medical situations,” Li said.
Icing a sprained ankle or sore muscle, long used to reduce pain and swelling, may in the longer run delay recovery and prolong pain, new research suggests.
In a preclinical study published in Anesthesiology, McGill University researchers found that even though cryotherapy (icing) eased pain in the short term, recovery time was more than doubled in some cases.
“These results highlight a paradox: treatments that reduce inflammation and relieve pain in the short term may, in some cases, interfere with the biological processes required for full recovery,” said lead author Lucas Lima, a research associate at the Alan Edwards Centre for Research on Pain.
The findings add to a growing body of research questioning the long-term benefits of common anti-inflammatory strategies, said Lima. Previous studies have shown that medications such as acetylsalicylic acid (Aspirin) can also extend the duration of pain, and animal research has suggested icing may delay tissue repair.
The new study provides, for the first time, direct evidence that icing can also affect the duration of pain itself, based on experiments with mice mimicking inflammatory and exercise-related injuries.
Icing is commonly used as part of the RICE protocol, a standard approach to managing injuries that includes rest, ice, compression and elevation. It is widely used by athletes, clinicians and in everyday injury care, but there is limited evidence for its long-term benefits, said the researchers.
“Our results suggest we need to better understand when anti-inflammatory strategies are helpful and when they are not,” said senior author Jeffrey Mogil, James McGill Distinguished Professor and E. P. Taylor Chair in Pain Studies.
He emphasized the results are not yet directly applicable to humans. A clinical trial is underway to test whether the same effect appears in patients recovering from procedures such as wisdom tooth removal.
About the study
“Cryotherapy and Duration of Inflammatory Pain in Mice” by Lucas Lima and Jeffrey Mogil et al. was published in Anesthesiology. The study was supported by the Canadian Institutes of Health Research Foundation and the Louise and Alan Edwards Foundation.
One of the study participants exerts force with their calf muscles while sensors measure electrical activity. (Photo: Ruoli Wang)
Even when people with incomplete spinal cord injuries can walk, everyday functions like standing, balancing or producing steady force may remain difficult. A new study shows why.
Using surface skin electrical sensors, a research team in Sweden identified previously unseen changes in motor coordination that result from incomplete spinal cord injuries (SCI). The study is the first to examine how individual motor units (nerve to muscle connections that create movement) work together in people with SCI.
“Our study reveals, at the cellular level, how the central nervous system adapts to the injury to control movement,” says Ruoli Wang, associate professor in biomechanics at Promobilia MoveAbility Lab, KTH Royal Institute of Technology. She says the researchers’ approach was completely non-invasive.
The study’s lead author, PhD student Zhihao Duan, says the researchers found the nervous system struggles to spread signals smoothly across muscles at low levels of exertion after the injury. And it appears to overcompensate at higher levels of exertion, sending “louder”, less refined signals.
Effect on motor units
Muscles move through hundreds or thousands of motor units, each turning on and off precisely to create smooth force. Composed of a single motor neuron and its connecting muscle fibres, these motor units respond to shared signals from the nervous system, much like different sections of musicians led by an orchestra conductor. That shared input is what allows them to act in coordinated patterns.
To explore how well these units coordinate under the control of the central nervous system, the team examined 25 people (including 10 control participants). They used high-density electromyography (HD-EMG) to measure electrical activity in the functionally similar calf muscles – soleus and gastrocnemius – while volunteers pushed lightly or moderately against a device.
Duan says that at 20% effort, fewer of the motor units in the two calf muscles were working in a shared, coordinated way compared with people without injury. As a result, their movements were shaky and unstable. “They were much less being driven by the same coordinated signal from the nervous system.” he says.
At a higher level of effort (50%) the SCI group showed stronger lowfrequency synchronization between the two muscles. The body loses flexibility and precision in control of the movement. “This could be a sign of the nervous system compensating by sending louder, less refined signals,” Duan says.
Unique insights
“One interesting finding is that after spinal cord injury the nervous system becomes more rigid and less able to change its approach as the muscles work harder. A healthy nervous system on the other hand is able to adapt its strategy as force demands, to adjust the shared neural drive level,” Wang says.
Although the study was limited by a small sample size and challenges in identifying enough motor units per muscle from the skin surface, Wang says the results offer unique insight into how SCI reshapes motor control.
“This finding may open the door to a new rehabilitation biomarker, helping clinicians and researchers design new neurorehabilitation strategies to re-tune the spinal cord control and to restore coordinated neural input,” she says.
