Explore 1,800+ exercises with an interactive muscle map that lets you click any muscle to see targeted exercises, including video tutorials and written instructions.

Watch this how-to video series on how to start strength training.

The human body in 3D

Zygote Body is a free human anatomy tool that allows users to explore the intricacies of the human body in stunning detail. With the click of a mouse, users can isolate by body system or view anatomical structures from any angle. Check out this...

Why yoga teachers are dissecting cadavers

Thousands of fitness professionals are choosing to attend cadaver workshops to improve their understanding of anatomy and their teaching abilities. Though 3D virtual models give students a fresh way to explore the human body, medical students say experiencing the intricacies in person is far more instructive. As fitness professionals increase their understanding of the muscular and skeletal systems, their movement cues and instructions evolve in tandem.

An interactive guide to the cardiovascular system

The cardiovascular or circulatory system moves blood throughout the body, ensuring cells have necessary nutrients and removing any waste. Click through this interactive 3D guide to explore the system as it crisscrosses the body via arteries, veins, and capillaries. This guide also includes similar breakdowns of the body and its other processes.

How muscles get their names

There are more than 600 muscles that crisscross the human body, and each has a name that's more than a simple label. Muscle names also typically communicate the muscle's size, behavior, length, location, appearance, direction, and attachments to bone. These names usually have Greek or Latin roots, such as in the case of the deltoid muscles, which are named in reference to the Greek letter delta (𐤃).

Explore what each organelle does within various types of cells

In "Cell Anatomy Viewer," users can explore interactive illustrations of animal, plant, fungal, and bacterial cells. Clicking on an organelle, such as a lysosome, the nucleolus, or the Golgi complex, provides descriptions of its characteristics and functions.

Explore how to safely start 'strengthmaxxing' with body weight—not actual weights.

A step-by-step guide to the Martha Graham technique

This BBC explainer walks you through Martha Graham's famous approach to dance, offering you six moves you can work into your exercise regimen—or Graham-inspired routine.

Exercise can lead to muscle microtears, but the body's repair systems cause those fibers to grow back larger.

Take a 360-degree look at biochemical activity from within a human cell

In this tour, users can observe the dynamic processes that occur within the basic units of the human body, including the production and transport of proteins and the assembly and disassembly of microtubules—thin, cylindrical structures that provide structural support and a means of moving material within the cell.

Adults need 2 days of muscle-strengthening activity weekly—yet most of us aren't doing that.

Discover how strength training may help your brain and what happens inside your cells when you work out with this original '1440 Explores' podcast.

Strength training doesn't require fancy equipment—cans, water bottles, and shopping bags work well.

How does muscle memory work?

Muscle memory is less about remembering how to ride a bike and more about what's happening in muscle cells. Increasing the cells' size, say by working out, leads to an increase in nuclei, which increases the production of mitochondria. When your fitness regimen falls to the wayside and you decide to re-enter the gym, these gains-based nuclei are already present to quicken muscle cells' adaptation to exercise.

Using fitness wearables to track muscle wasting in astronauts

All that exercising, and astronauts still are likely to lose a large amount of muscle mass while in microgravity. Astronauts can lose up to 20 percent of their muscle in as little as five days in space. Currently, tracking muscle loss means waiting until astronauts land to remeasure their muscle density post-trip. This article explains a NASA-backed fitness wearable that may be able to track muscle atrophy as it happens.

Explore human anatomy with these beautiful images

The Human Organ Atlas offers detailed 3D images of dozens of human organs. It was created with very bright X-rays from a particle accelerator, which is formally called a synchroton imaging method.

Astronauts exercise on the International Space Station

Astronauts maintain bone, muscle, and cardiovascular health with physical activity. It's crucial that they make time to exercise for approximately two hours per day. This resource offers a behind-the-scenes look at how high-intensity workouts help prevent muscle atrophy, bone density loss, and aerobic decline during monthslong space missions.

Explore the heart in this interactive 3D model

The heart is the fleshy muscle at the heart (pun intended) of the circulatory system. The heart is segmented into four chambers: two for intake (the right side) and two for output (the left side). Controlled via the autonomic nervous system, also known as the involuntary nervous system, the heart typically beats 60 to 100 times per minute, sending nutrient- and oxygen-rich blood throughout the body.

Strength training appears to make for a healthier, youthful-looking brain.

Explore a collection of moon interactives from NASA, including a 3D lunar surface explorer, a tool for classifying moon rocks, and an interactive map for observing the moon each day of the year.

Small ways to improve your health today: an animated guide

What are some ways that you could start making a positive impact on your health today? This animated gallery overviews several health topics, including sleep and hydration, and offers ways to improve that aspect of your life. Clicking on the...

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.

Official recommendations state that healthy adults should perform progressive resistance training that increases weight and repetitions over time.

Modern bodybuilding evolved in the 19th century.

Explore an interactive 3D model of the brain

The brain contains about 86 billion neurons—nervous system cells—and controls vital bodily functions via electrochemical signals. Neurons form circuits through axons, and different brain regions use these circuits to perform specific tasks.

Complex molecular reactions in our tissues cause muscle contraction

When we want to move a muscle, a signal travels from the brain and into the muscle cells in question, sparking a chemical reaction that causes the muscle's smallest contractile units—sarcomeres—to shorten, forcing the muscle to contract.

The anatomy of 'Mashle,' as described by a doctor

"Mashle: Magic and Muscles" is a manga and anime in which a seemingly magicless man performs outsized feats he blames on "muscle magic." In this 15-minute video, a doctor breaks down the anatomy and biomechanics of some of the feats performed by Mash, the series' main character who's spotted flying a broom via leg pumping and reading magical texts while sitting in an invisible chair (i.e., single-leg squat).

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.

Explore Pompeii with an interactive map packed with 60+ key sites

This tool provides detailed information on major landmarks—from the Villa of Mysteries to the House of the Tragic Poet—and suggests themed walking routes based on visit length. A companion app adds virtual reconstructions and a full audioguide.

Muscular system explained

Skeletal, cardiac, and smooth muscles form the system that powers movement, survival, and daily life. Skeletal muscles are voluntary, enabling conscious actions like lifting or walking, while cardiac and smooth muscles are involuntary, controlled by the autonomic nervous system. From every heartbeat to each breath, these three muscle types work in harmony to keep you moving, thriving, and alive.

View a gallery of images and videos of over 200 types of cells

Funded by the National Institute of General Medical Sciences of the National Institutes of Health, the Cell Image Library houses over 60,000 pieces of media, including microscopic photographs, time-lapse videos of cellular activity, and 3D reconstructions of organic processes.

Explore an interactive timeline of Earth's 4.5-billion-year history to visualize shifting landmasses and oceans, view the locations of significant asteroid impacts, and learn about major geological and biological events.

Learn about 12 basic yoga postures

A typical yoga class runs students through a sequence of basic postures, also known as asanas. This illustrated guide outlines 12 poses—including the “plough,” “fish,” and “crow”—and breaks down the specific benefits.

What is the muscular system?

The muscular system comprises three distinct types of muscle: smooth, cardiac, and skeletal. Cardiac muscles make up the heart, whereas smooth and skeletal muscles are found throughout the body. Smooth muscles line blood vessels and most organs, and skeletal muscles are responsible for moving the body or holding it stationary. All muscles are made of muscle cells or fibers, which give them the ability to contract.

A 15th-century university student documented a surprisingly detailed fitness plan.

Health officials recommend at least 150 minutes of aerobic exercise per week and 2 sessions of resistance training, targeting each major muscle group.

Use the MyPlate widget to create your own meal plan

Enter your gender, age, weight, height, and activity level into the USDA's MyPlate widget for a personalized meal plan designed to be easy to understand. After viewing about how many calories are recommended to maintain your current weight, users...

Examine this captivating animation 'building' a human—illustrating the roughly 40 weeks of fetal development.

Search this citation-heavy database of nutrition and supplement research

Explore a reference site that aggregates and summarizes peer-reviewed studies on hundreds of supplements and dietary interventions. It is ad-free and funded by subscriptions, making it a health resource without a financial stake in what you buy.

Exercise can change your genes without changing your DNA.

Optimal human functioning requires movement

There is now ample evidence to back the centuries-old hypothesis that exercise is critical to human health. This review article explores the latest discoveries in exercise science, including how exercise is intrinsic to maintaining our organ systems throughout life.

BKS Iyengar emphasized yoga's physical aspect

The guru’s 1966 book “Light On Yoga” included detailed instructions for over 200 postures, presenting a version of yoga that emphasized it as a form of exercise with controlled breathing, believing that its physicality was the key to unlocking its spirituality. The book was the first mass-market manual to show the poses, furthering the Western impression that yoga was primarily about exercise.

The reason some people love exercise may be because of their microbiome

Certain gut microbes in mice trigger dopamine release and drive motivation to exercise more. Scientists are investigating whether humans carry similar microbial patterns that influence our natural inclination towards movement, exploring how unseen microbial ecosystems may shape mammalian fitness behavior and reinforce innate reward pathways. (Some users may experience a paywall.)

What does the muscular system do?

The muscular system is responsible for movement by and throughout the body. Smooth muscle contractions push food and blood through the digestive tract and blood vessels, respectively. Skeletal muscles are responsible for voluntary movement or lack thereof by the body. Cardiac muscle controls the beating of the heart, which is the pump that powers the circulatory system responsible for distributing energy and nutrients to cells across the body.

An interactive dive into the immune system

Our bodies are equipped with an incredible system able to fight off invasive pathogens to protect us from illness. The complicated system includes lymph nodes, the spleen, bone marrow, and even the tonsils. But this same system can turn against itself, a condition known as autoimmune disorders. Follow along with this thorough, engaging explainer on the human body's defense system.

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.

Explore a series of bedtime exercises to improve sleep

Low-impact, mindful movements can potentially help the body and mind relax before sleeping. Such exercises could be a helpful complement to regular exercise during the day.

How stress affects every organ in the body

If you are a visual learner, this resource is for you. Not only does this article from the World Economic Forum outline the causes of modern stress along with helpful strategies, but they have created an approachable infographic to show exactly how stress manifests throughout our different bodily systems. Pair this visual guide with our other resources to gain a deep knowledge of stress and the human body.

Explore the abundance of different types of cells in the human body

Lacking a nucleus and other organelles to maximize space for oxygen-carrying hemoglobin and enhance maneuverability through narrow capillaries, there are about four times as many red blood cells and platelets as all other cell types in the body combined. However, about half of the body's cell biomass consists of skeletal myocytes, or muscle fibers.

View a library of custom programs that can be loaded onto graphing calculators, including productivity tools, reference materials, games, and interactive applications, such as prom proposals.