How A Yoga Pose Makes Energy, While Building Muscle & Bone At The Same Time

Yoga for strength and bone strength: the short answer

Yoga for strength and yoga for bone strength run on the same mechanism: a pose held still, with the muscles on both sides of every joint pulling against each other. That is isometric yoga, and in the same thirty seconds it works muscle, loads bone and produces what people in a class feel as energy.

Iyengar yoga is the style developed by Mr BKS Iyengar. In the 20th century he did more than anyone to set down traditional Indian yoga, through his books and his teaching, and he pioneered the use of props. It is sometimes called modern classical yoga, and it’s the style we teach at Flametree. This page sits in our balance, bones and strength notes.

Here is the whole article in short form.

• A pose that looks still is not resting. Press the back heel down in Extended Triangle Pose (Utthita Trikonasana) and the floor pushes back, up the ankle, the shin, the knee and the thigh into the hip. One instruction at the foot wakes up the whole leg.
• The energy comes from pulling two ways at once. A pose works like a tent: the pole only stands up because the guy ropes pull against each other. Press down through the feet and lift up through the spine, and the leg becomes firm and springy without moving. Dr Ray Long, an orthopaedic surgeon who studied with Mr BKS Iyengar, calls this co-activation. Joel Kramer mapped five of these “lines of energy” in Triangle Pose alone.
• “Energy” is a feeling, not a substance. It is what several real things feel like when they happen together: muscles working, force travelling through the skeleton, nerve signals, the breath spreading through the trunk, and attention going where it usually never goes.
• Holding a pose is real strength training. A muscle working hard without changing length is isometric work, like holding a heavy shopping bag with the elbow bent. Half a minute in a standing pose does that to dozens of muscles at once, and it works both sides of each joint together, which protects the joint.
• Bone listens to muscle. When a muscle pulls on its tendon, the bone bends by a tiny amount, fluid squeezes through tiny tunnels inside it, and the cells living there signal for new bone along the exact line of the pull. That is Wolff’s law, worked out in the 1890s and still standing.
• Yoga loads bone from angles that walking never reaches. Triangle, Warrior 2 and the standing twists pull the hip and spine sideways, on a slant and in a spiral, with no jumping and no impact. One of the places they reach is the neck of the thigh bone, where older bones most often break.
• Long holds and props are the point. A chair, wall or block lets you stay steady long enough for muscle and bone to get the message.
• The bone evidence is careful rather than miraculous. In a ten-year study led by Dr Loren Fishman, 227 volunteers who did twelve poses a day, thirty seconds each, showed improved bone density in the spine and the thigh bone (femur), and no yoga-related serious injuries were reported (Topics in Geriatric Rehabilitation, 2016). Two honest limits: there was no comparison group, and nobody has measured the “energy”, because it is a feeling.
• Not falling over may matter as much as denser bone. Standing poses train balance, and most fragility fractures start with a fall.
• The core is a can, not a six-pack. Four walls: the breathing diaphragm as the lid, the pelvic floor as the base, the deep tummy muscles around the sides, and the small muscles along the spine at the back. Sit-ups train one wall. A held standing pose, a plank or a chair pose makes all four work together.
• Mr BKS Iyengar taught through the skin on purpose. First draw the muscles in so they hug the bone, then extend out from that firm centre until even the skin is alive and spread. A patch of skin that feels dull or twisted is telling you something underneath is out of line.
• Five actions, one pose, every time. Press down. Lift up. Draw in. Extend out. Observe everything.
• Try it: three short holds you can do at home, with a doctor caution.
• Where to learn it. Flametree Yoga Studio teaches Iyengar yoga in Darwin and LIVE online, and every ordinary class is built on these same five actions.

Why does a yoga pose that looks still make energy?

Because inside it, nothing is still. Stand in Extended Triangle Pose (Utthita Trikonasana) and, to anyone watching, you are holding a shape. Nothing moves.

Try this. Stand up and press your back heel firmly into the floor. The floor pushes back. That push does not stop at your heel. It travels up the outside of your ankle, up the shin, through the knee, into the thigh and into your hip. One small instruction at the foot has woken up the whole leg.

That is the first secret of a yoga pose. Every instruction sends a wave through the body, and a good teacher chains those waves together until the whole body is working as one piece. This is exactly what an Iyengar yoga class at Flametree Yoga Studio in Darwin is doing when the teacher says “press the outer edge of the back heel down”. Our Triangle Pose note goes through the pose step by step.

Where does the energy actually come from?

From pulling in two directions at once. Think about a tent. The pole stands up because the guy ropes pull on it from opposite sides. Loosen one rope and the tent sags. Pull all the ropes evenly and the tent is firm, yet springy. Nothing is moving, but everything is working.

Your body in a pose works exactly like that tent. Press down through the feet, and lift up through the spine. Reach out through the fingertips, and draw the shoulder back in. The muscles on the front of your thigh and the muscles on the back switch on together and pull against each other around the bone. The leg does not move, but it becomes firm, springy and awake.

Dr Ray Long, an orthopaedic surgeon who studied with Mr BKS Iyengar, calls this co-activation, and says it gives the body an “alive and springy feel”. Joel Kramer, writing in Yoga Journal in 1980, called these pulls “lines of energy”. He mapped five of them in Triangle Pose alone: down the back leg, down the front leg, out through the spine, out through the top arm and down through the lower arm. Each one pulls against another.

So what is this “energy”, really? Here is the honest answer. It is not a measurable substance flowing through your body. It is the feeling you get when several real things happen at once: muscles working, forces running through your bones, nerves sending messages up and down, your breath spreading through the trunk, and your attention travelling into places it usually never visits.

Kramer wrote that through yoga you can change the quality of this energy and enlarge the body’s capacity to transform it. Mr BKS Iyengar said it in four words in Light on Life: “Extension is attention, and expansion is awareness.”

How does the same pulling build muscle?

Hold a shopping bag with your arm bent for a minute. Your arm does not move, but it starts to shake. That is your muscle working hard without moving, which is called isometric work, and it is real strength training. A yoga pose held for half a minute or more does the same thing to dozens of muscles at once.

There is a bonus a gym machine cannot give you. A machine usually works one muscle on its own. A pose asks the muscles on both sides of a joint to work together, so the joint is pulled into its best position and protected while the muscles get stronger. Do it often enough and your brain learns the pattern, the way you learned to ride a bike. You still hold the lines, but with less effort. Kramer called that “dynamic relaxation”: the pose stays alive while the struggle drops away.

If you want to know how far yoga goes for muscle size, see our note on whether yoga can build muscle.

Why do long holds and props matter for strength?

Because a muscle only works hard if the pose stays still long enough. Most exercise moves fast: the muscle fires, then rests. In Iyengar yoga a pose is often held for a minute or more, and a muscle has to keep working the whole time with no momentum to help it. That shake partway through a hold is the muscle working, not a sign that anything is wrong.

This is where props earn their place. A block under one hand, a chair under a thigh or a belt looped around the feet are not training wheels. They hold the pose steady enough, for long enough, that the muscles doing the real work have nowhere to hide. A chair or wall in Warrior 3 can let you keep the standing leg strong for ten breaths instead of two. As one student, C., put it: “If you are new to Iyengar yoga, don’t be put off by the chairs, blocks and belts. When used properly they can teach you a lot!”

Mr BKS Iyengar taught from an old line of the Yoga Sutra, sthira sukham asanam: a pose should be steady and comfortable, both at once. Steady is the strength part. Comfortable comes once the muscles learn to hold it.

A pose also has to be well made for the load to land in the right place. In Triangle Pose that means both legs straight, the top arm straight, and the pelvis extended back rather than tipped forward. A teacher who fusses over your back leg or your top arm is helping the forces run usefully through the hip.

How do you build upper-body strength in yoga, all the way to Forearm Balance?

Step by step, with your own body as the weight. In the Iyengar method the arms are prepared with Plank, Downward-Facing Dog, Upward-Facing Dog, Four-Limbed Staff (Chaturanga Dandasana, the low plank) and Side Plank (Vasisthasana), long before anyone goes upside down. These teach you to carry weight through the hands and arms without sinking into the wrists, elbows or shoulders. That is yoga for strength in the upper body, and it builds towards poses like Forearm Balance.

What does Forearm Balance (Pincha Mayurasana) actually work?

Almost everything, even though it looks still. In Pincha Mayurasana (Feathered Peacock Pose, or Forearm Balance), the forearms press down and the floor pushes back up. The triceps (the muscles at the back of the upper arm) and the muscles around the elbows steady the arms. The serratus anterior (the muscle wrapping the side ribs), the trapezius, the rotator cuff and the deltoids lift and steady the shoulder girdle (the collarbones and shoulder blades). The abdominal, back and leg muscles organise the rest of the body so it does not collapse, sway or arch too far.

You are holding, but it is not altogether static. It is the same two-way pull this whole article is about. In these poses, your own body becomes the weight.

Why do strong legs make Handstand feel lighter?

Because the arms cannot do all the work. In Handstand (Adho Mukha Vrksasana) the palms press firmly, the elbows stay straight and the upper arms lift. Strong, active legs and a firm abdomen lift the body away from the shoulders. Passive legs make the body feel heavier. In Headstand (Salamba Sirsasana) the forearms form the base and the shoulders stay lifted. In Shoulderstand (Salamba Sarvangasana) the upper arms, shoulders and upper back are the foundation.

At first these poses take a lot of muscular effort. With regular, precise practice the effort spreads out: the forearms press more evenly, the shoulders lift better, and the legs start to help. The poses get lighter, not because strength is no longer needed, but because the whole body has learnt to work together.

How do you work towards Forearm Balance safely?

Get comfortable upside down in other inversions first, and build the arms in stages. Chris Lalor’s suggestions:

• Prepare with Plank, Downward-Facing Dog, Upward-Facing Dog, Chaturanga and Side Plank.
• Half Forearm Balance, forearms down and feet on the floor, with the hands holding the outer edges of the mat.
• Walk the feet up the back of a chair.
• A belt above the elbows and a block between the hands, to keep the forearms parallel and facing forward.
• Use the wall before trying to balance away from it.

Forearm Balance is very challenging for most people when they first meet it, and it has risks that should be respected. Learn it with a teacher, in the studio or LIVE online. Our guide to yoga inversions covers the gentler upside-down poses to start with, and who should take care.

Iyengar teaching holds that this kind of strength is not hardness, gripping or strain. Mature strength lets you stay steady without rigidity, fully extended without tension, and alert without agitation. As Chris puts it: "We build the body so that, eventually, we can become quiet within it."

How does a yoga pose load bone, and why does that matter?

By pulling on it, because bone listens to muscle. Most people think bone is like a rock. It is not. Bone is living tissue, and it rebuilds itself all the time. It grows thicker along the lines where it gets pulled and squeezed, and thins out where it is left alone. A German doctor called Julius Wolff worked this out in the 1890s, and it is still called Wolff’s law.

Here is how the message gets through. Every muscle is tied to a bone by a tendon. When the muscle pulls, the tendon tugs on the bone, and the bone bends by a tiny amount. Deep inside the bone live cells called osteocytes, sitting in little caves connected by tiny tunnels. When the bone bends, fluid squeezes through those tunnels, a bit like squeezing a wet sponge. The cells feel that and send out a signal: build here. Bone-building cells then lay down new mineral along the exact line of the pull.

Now think about an ordinary day. Sitting, walking on flat ground and standing at the sink all send the same dull signal, in the same direction, again and again. There is not much in that for the bone cells to work with.

A well-made standing pose is different. Both legs press down. The top arm reaches up. The pelvis rolls back. The front thigh bone winds one way while the back one winds the other, all at once. When muscles on both sides of a joint pull against each other like this, the bone is loaded strongly, with no jumping and no impact. And because Triangle, Warrior 2 and the twists pull on the hip and spine sideways, on a slant and in a spiral, they load bone from angles that walking and running never reach. Those include the neck of the thigh bone (the femoral neck, the short angled bridge between the hip joint and the thigh), one of the places older bones tend to break.

We are not saying a pose prevents a broken hip. Nobody can honestly say that. What we can say is that this part of the body spends most of its life getting one dull signal, and a well-made standing pose gives it a far more interesting one.

Is there evidence that yoga poses support bone?

Yes, and it is careful evidence rather than a miracle. The question researchers ask is whether yoga bone density gains show up on a scan. Dr Loren Fishman at Columbia University led a ten-year study of 741 volunteers recruited online. They did a routine of twelve yoga poses, each held for thirty seconds, about twelve minutes a day. In the 227 people who kept it up, the scans showed improved bone density in the spine and the thigh bone (femur), and no yoga-related serious injuries were imaged or reported. The results were published in Topics in Geriatric Rehabilitation in 2016 (Lu, Rosner, Chang and Fishman).

Just as important, the balance you learn standing in those poses means you are less likely to fall in the first place, and falls are how most fragility fractures happen. For the balance research, see our page on Iyengar yoga and falls.

Three honest limits. The people in that study chose to do yoga, and had no comparison group, so the result is a before-and-after picture rather than a fair test. The gain was clear in the spine and femur but was not significant for the total hip in one group. And nobody has measured what happens to the “energy” itself, because it is a feeling, not a substance. What has been measured is the bone, the muscle and the balance.

Why did Mr Iyengar keep talking about the skin?

Because the skin is how you know whether the pull is right. Mr BKS Iyengar taught in two directions. First, “from the skin to the bone”: draw the muscles in so they hug the bone and the joint sits in its centre. Then “from the bone to the skin”: from that firm centre, extend out until even the skin is alive and spread.

Your skin is packed with sensors, so if a patch of skin on the inner ankle or the back of the knee feels dull or twisted, something underneath is out of line. He wrote in Light on Life: “The skin provides our outermost layer of intelligence.” That is why the pose is never just a shape. It is a conversation between your skin, your muscles, your bones and your mind.

What is the core, and why is it a can rather than a six-pack?

The core is not the muscles down the front of the tummy. It is a pressurised can with four walls: the breathing diaphragm as the lid, the pelvic floor as the base, the deep tummy muscles as the walls, and the small muscles along the spine at the back.

Sit-ups train one wall. A held standing pose, a plank or a chair pose makes all four walls work together. That is what holds the low back up, and it is the base that every one of Kramer’s lines starts from. Get the can working and everything else has something to push from.

What can you try at home to feel a held pose working?

Three short holds, each with a wall or a chair so you can stay steady. They are simple on purpose. Go gently, stop if anything hurts sharply, and never force. If you have been told your bones are thin, have had a fracture, or have a joint injury, talk to your yoga teacher, yoga therapist, and your doctor if you wish, before you try them.

A wall hold for the arms and shoulders

1. Stand side-on to a wall, feet hip-width apart.
2. Press one palm flat into the wall at shoulder height and lean in gently, until your shoulder and upper arm are working to hold you.
3. Hold for 20 slow breaths. Notice which muscles are doing the work. It is probably not the ones you expected.
4. Swap sides.

One-leg balance for the hip

1. Stand side-on to a wall or the back of a steady chair, feet together.
2. Shift your weight onto one leg, resting a hand lightly on the wall or chair.
3. Bring the sole of the other foot to your standing ankle or calf, never the knee.
4. Hold for five slow breaths, feeling the standing leg and hip doing real work.
5. Swap sides.

Standing fully on one leg puts your whole body weight through one hip and thigh bone instead of two. The wall or chair does not make the work smaller. It lets you stay long enough for it to count.

Locust for the back of the body

1. Lie on your front, forehead down, arms by your sides, palms down.
2. Breathe in, lift your chest and head a few centimetres, and press the tops of your feet into the floor.
3. Hold for three slow breaths, keeping the lift small and controlled.
4. Lower slowly, head turned to one side.

In the Iyengar tradition, a supported backbend over a chair, or a small lift in Locust, asks the spine to carry load from front to back, a direction almost nothing else in daily life provides. Small and controlled beats big and forced. Our backbend yoga page shows the chair versions.

What do you get from one pose, every time?

Press down. Lift up. Draw in. Extend out. Observe everything. Do those five things in one pose and you have made energy, worked muscle and loaded bone in the same thirty seconds.

And to do them at all, your mind has to leave its worries and go into your body. That is the part nobody warns you about, and it is the part people come back for.

This post covers only the benefits with a clear mechanism behind them. Flametree has published elsewhere on the wider benefits of Iyengar yoga and pranayama, including Yoga For Bones & Osteoporosis and how Iyengar yoga builds strength in Darwin.

Frequently asked questions

Does holding a yoga pose count as strength training?

Yes. Holding a pose is isometric work: the muscle works hard without changing length, the way your arm works holding a heavy shopping bag with the elbow bent. Standing poses held for thirty seconds or more work dozens of muscles at once, and they work the muscles on both sides of each joint together, which protects the joint.

Can yoga really load bone without jumping or lifting weights?

Bone responds to being pulled and squeezed, not only to impact. When muscles pull on a bone through their tendons, the bone bends by a tiny amount and its cells respond by laying down new bone along the line of the pull. A ten-year study led by Dr Loren Fishman, published in Topics in Geriatric Rehabilitation in 2016, reported improved bone density in the spine and the thigh bone in the 227 volunteers who kept up twelve minutes of yoga a day. There was no comparison group.

What does energy mean in yoga?

In this context it means the lived feeling of the body becoming alive, connected and awake in a pose. It is produced by muscles working, forces travelling through the skeleton, nerve signals, breath and attention all happening at once. It is not a substance that can be measured, and Joel Kramer, who popularised the term lines of energy, said himself that energy was an approximate word for the experience.

Which yoga poses are best for bone strength?

Standing poses such as Extended Triangle Pose (Utthita Trikonasana), Warrior 2 (Virabhadrasana II) and the standing twists load the hip and spine from several directions at once, including the neck of the thigh bone where fractures are most common. They are held for a minute or more, with a wall, chair or block where that helps you stay steady.

Do I still need to lift weights if I do yoga?

Weights and yoga load the body in different ways. Lifting adds load in steps, and it is the approach most often studied for bone. Yoga holds the hip and spine under load from sideways, slanting and spiralling directions, needs no equipment and no impact, and trains the balance that helps stop a fall. What suits you depends on your health and on what you will keep doing, so talk to your yoga teacher, yoga therapist, and your doctor if you wish.

Does yoga build muscle?

Yes, within limits. Holding a pose is isometric work, so the muscles on both sides of a joint contract hard without the joint moving, and a standing pose held for thirty seconds or more does that to dozens of muscles at once. Expect usable, everyday strength and better joint control rather than size. Our page on whether yoga can build muscle goes into more detail.

Is yoga good for osteoporosis?

The research is encouraging and it is careful rather than miraculous. Dr Loren Fishman’s ten-year study reported improved bone density in the spine and femur in 227 volunteers who did twelve poses held for thirty seconds each, with no yoga-related serious injuries reported (Topics in Geriatric Rehabilitation, 2016). Those people chose yoga themselves and there was no comparison group. If you already have diagnosed osteoporosis or a past fracture, some poses, particularly deep forward bends and strong twists, need modifying, so talk to your doctor and tell your teacher before class.

How long before yoga makes a difference to bone?

Bone is slow. The Fishman study ran over ten years, not weeks, and a bone density scan is not usually repeated more often than every one to two years. Strength and balance move much faster than bone does, often within weeks, and they are what you will actually notice first. Anyone promising a change in bone density in a month is not describing how bone works.

Which yoga poses build upper-body strength?

Plank, Downward-Facing Dog, Upward-Facing Dog, Four-Limbed Staff (Chaturanga) and Side Plank are the base. They teach the hands, arms and shoulders to carry your weight without sinking. From there, Headstand, Shoulderstand, Handstand and Forearm Balance load the arms and shoulders further, learnt in stages with a teacher.

What yoga hold can I try at home to build strength?

A wall hold is the simplest. Stand side-on to a wall, press one palm flat at shoulder height, lean in gently and hold for 20 slow breaths, then swap sides. A steady shake partway through is the muscle working. If you have thin bones, a past fracture or a joint injury, talk to your yoga teacher, yoga therapist, and your doctor if you wish, first.

Where can I learn this properly in Darwin or online?

Flametree Yoga Studio teaches Iyengar yoga in Darwin, in the studio at Woolner and Coolalinga, and LIVE online, with Chris Lalor, a Senior Iyengar Yoga Teacher. Your first class is free if you are new to Flametree: in the studio, if you have lived in the NT for three months or more, and online, for anyone new.

Practise this at Flametree

Flametree Yoga Studio teaches Iyengar yoga in the studio at Woolner and Coolalinga in Darwin, and LIVE online.

• New to Flametree? Your first class is free. In the studio, just come along. Online, go to our online class list, click the class time you want and we email you the link to join.
• Beginners: new students, and anyone who has been away three months or more, can get a half price 10 class pass with 2 extra classes free, to use online, in the studio, or both. See the beginner half price pass.
• Already practising yoga? The same half price 10 class pass with 2 extra classes free, for new students and for anyone away three months or more, is also available as the non-beginner half price pass.
• See every class time, including online classes, on the timetable.

Can’t make a class? Practise at home with our video courses.

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Flametree Yoga Studio, Darwin and live online. This article is general information, not medical advice. If you have osteoporosis, a recent fracture or a joint injury, talk to your doctor and tell your teacher before class.

Sources: Joel Kramer, “Yoga as Self-Transformation”, Yoga Journal, 1980. Ray Long, The Key Muscles of Hatha Yoga (Bandha Yoga, 2006). Mr BKS Iyengar, Light on Life (2005). Lu Y-H, Rosner B, Chang G and Fishman LM, a ten-year study of a twelve-minute daily yoga routine and bone density, Topics in Geriatric Rehabilitation, 2016, doi 10.1097/TGR.0000000000000085.