'Viscoelasticity' allows muscles to be elongated briefly after stretching

Microtears in muscles from exercise cause fibers to grow back larger

Placing muscle under increased load or stress causes damage that requires rest to repair, leading to stronger, more enduring muscle over time. Muscles adapt to such increasing demands by improving their efficiency with approaches that include increasing the number of mitochondria housed in hundreds of thousands of muscle cells.

Physiological muscle memory allows us to quickly regain lost musculature

The term "muscle memory" is most often associated with the neurological kind, which involves the development of strong and efficient neural pathways in the brain and spine. Physiological muscle memory also slows the loss of muscle mass, with both types affected by genetics and diet.

One of the leading theories behind muscle movement

According to the Sliding Filament Theory, skeletal muscle contraction is made possible by sarcomeres, which are made of bundles of myosin and actin proteins inside muscle cells. Myosin pulls itself along actin to contract a muscle, shortening the muscle and its cells and enabling physical movement. It then releases its grasp on actin so it can start the process over again if so commanded.

Myokines are molecules that facilitate some of the benefits of exercise

When muscles contract, they release ‘hope molecules’ (myokines) such as IL-6 and irisin. These proteins then travel through the bloodstream to reduce inflammation, improve insulin sensitivity, and even support brain repair. This piece illustrates how movement triggers a systemic healing cascade throughout the human body.

Exercise helps make your arteries more elastic

Regular aerobic exercise releases nitric oxide, a key molecule that relaxes blood vessel walls and improves vascular function. These exercise-induced adaptations make the heart work more efficiently and blood vessels become more elastic, leading to improved circulation and lowered cardiovascular risk.

Flexible integrated circuits can be built from carbon nanotubes and elastic materials

Stanford researchers arranged the nanotubes in fishnet-like networks that allow deformation without loss of function. The stretchable ICs have been shown to power micro-LED displays and may be used in smart clothing.

Viscosity is a fluid's resistance to flow, which varies with temperature

Liquids become less viscous as temperature increases, while gases become more viscous and therefore flow more slowly. The increased gas collisions at higher temperatures contribute to greater friction between streamlines, increasing viscosity.

When experiencing turbulence, fluid elements undergo stretching and folding

Simulations show patches of fluid particles, such as splashes of milk, bend under turbulent flow, creating curvature that grows linearly then exponentially. This accelerated deformation enhances folding and mixing faster than other methods, such as stirring or beating.

How skeletal and smooth muscles differ

Skeletal and smooth muscles are two of the three muscle types found throughout the body. The former is attached to bones via tendons, enables limb movement, and is consciously controlled. The latter is found lining blood vessels and hollow organs (e.g., the intestines, stomach, and esophagus) and is managed by the autonomic nervous system, which means it's outside conscious control.

Winter Olympic sports highlight various laws and principles of physics

Figure skaters leverage the conservation of angular momentum during spins by tightening their bodies, and the skintight suits used in ski jumping help reduce drag. Centripetal force allows speedskaters to make tight turns, while friction on skis helps ski mountaineers climb slopes. No action can violate the conservation of energy.

Endurance art strains and exhausts the body

Artists like Marina Abramović are known for testing the limits of human endurance. Endurance art can involve carrying heavy objects or posing uncomfortably for long durations. (This resource contains some artistic depictions of violence.)

Collagen supplements have become a multibillion-dollar industry

Beginning in our 20s, the amount of this protein in our skin, muscles, and connective tissue declines. But independent, high-quality studies—like those that are double-blind—have not yet shown a significant association between their use and evidence of it improving skin elasticity, reducing wrinkles, or combating hair loss. Some collagen supplements do seem to help with joint pain and knee function, but NPR cautions that studies on that purpose are industry-funded.

The longest word in English is 189,819 letters long

The wildly-winding word (so long that we can't fit it here) is the proper name for titin, a protein that keeps muscles elastic.

Adhesion molecules and intercellular junctions allow cells to connect together

While some organic structures are mostly composed of non-cellular components (e.g., collagen and calcium phosphate minerals in bones), tissues and organs composed of connected cells rely on specialized proteins and connections to create watertight seals that protect cells within the interior from environmental molecules.

The universe expands by stretching space itself, not into anything beyond it

Thanks to Einstein’s relativity and Hubble’s observations, scientists understand that space stretches, like rising bread dough between raisins, with no "outside" to expand into. Some theories suggest our universe might be just one "bubble" in a vast multiverse, possibly floating on a higher-dimensional surface called a brane.

Tardigrades’ intrinsically disordered proteins may help preserve biological matter

Researchers have attempted to create more drought-resistant crops by introducing proteins that help protect tardigrades in their dehydrated tun state. The proteins’ ability to stabilize molecular degradation may allow scientists to develop refrigeration-free storage for vaccines, insulin, and blood.

A Venus flytrap's hairs convert sensory touch into electrical signals

A stretch-activated ion channel called DmMSL10 acts as an amplifier, converting grazing contact into a strong impulse that the plant uses to react and close its jaw. To distinguish prey from raindrops or other stimuli, the jaw only closes when the hairs are touched twice in quick succession.

Synaptic plasticity allows neurons to communicate effectively and form memories

First proposed in 1949, synaptic plasticity allows the brain to adjust communication strength between neurons. This ability to change synaptic strength—either briefly or over long periods—is essential for learning and memory, with long-term synaptic plasticity forming the basis of how memories are stored.

Stem cell therapies show promise in treating spinal injuries

Researchers have long hoped to use stem cells in regenerative medicine to help patients with spinal cord injuries restore sensation and movement. A 2024 clinical trial illustrates how stem cells derived from patients' fat tissue could help spur the creation of new cells in the spinal cord.

Your feet can expand—permanently—due to pregnancy

A hormone called relaxin loosens tissues in the body to allow them to expand during pregnancy, affecting muscles and body parts—including the feet. The structural changes that occur in the foot as it expands are sometimes permanent. This article states that researchers have found as many as 61% of new moms did not have their foot sizes return to their prepregnant state. (Some users may encounter a paywall.)

Wrestlers maintain the illusion of a fictional narrative through 'kayfabe'

Outsiders are often confused by wrestling fans’ emotional investment in predetermined matches. After all, how can you be invested in a scripted sport? That question misses a key component of fans' love for pro wrestling. They suspend their disbelief in the same way that readers of novels do.

Shrink-wrap is created through a treatment of plastic with high-speed electrons

Atoms in polyethylene are bonded in long strings called polymer chains, which can be destabilized by removing hydrogen atoms via collisions with electrons. These gaps serve as bonding sites for neighboring chains to bond and undergo cross-linking, strengthening the plastic while making it more malleable.

Chemistry-informed advice for cooking pasta, including how to prevent clumping noodles

On a molecular level, pasta dough consists of protein structures that hold starch molecules, and the starches absorb water during cooking, forming a gel that softens the pasta. Pasta should not be rinsed after cooking. Instead, some of the pasta water should be added to the pasta sauce, as the gelatinous starch will help the sauce stick to the pasta.

Yoga has become a popular tool for veterans dealing with PTSD

As the practice has become more popular in the West, it’s been incorporated into the Department of Veterans Affairs’ treatment plans for post-traumatic stress disorder. Veteran instructors say that although yoga and the military might seem like odd fits, they share many commonalities, including a rigorous approach. (Some readers may experience a paywall.)

50 years of research has focused on unraveling the relationship between music and frisson

One insight reveals that musical passages with surprising volume changes or unexpected harmonies and beauty are more likely to trigger frisson, perhaps because they upend listeners' expectations.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

Urushiol, the oily toxin in poison ivy, can remain allergenic on clothing for years.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world