In fact, centuries before Instagram and activewear, "doing yoga" didn't involve the body at all.
At its core, yoga is a practice for tapping into your mind and poses are just one way of doing that.
Yoga's philosophy is based on eight limbs; only one of them, asana, is about the poses. The rest: yama, niyama, pranayama, pratyahara, dharana, dhyana and samadhi, are best described as moral and ethical codes to live by.
These codes are intended to help people live meaningful and purposeful lives; to have compassion, and not be ruled by the ego and mostly useless thoughts that can control our lives if we let them.
But many of us do yoga because of its physical benefits, improved strength and balance, as well as greater flexibility (which can make everyday activities easier on your body).
A national survey in Australia found that while health and fitness was often a reason for people starting yoga, many then discovered its stress-busting powers and continued with it for this reason.
Indeed for those who use yoga to manage a health or medical condition (which was one in five of the people surveyed), the primary health-related motivation seemed to be stress management.
Yoga is usually taught in a class, but once you're experienced, you may prefer to do it on your own at home.
Mind/body connection explained
The terms 'mindfulness' and 'mind/body' connection are thrown around a lot in the yoga world.
But what do they actually mean, and how do they relate to making shapes with your body?
Mindfulness or 'mindful awareness' is focusing your attention on what is being experienced here and now, without reacting to or judging it.
It involves learning to recognise when you're getting carried away by thoughts and then deliberately choosing to ignore them in favour of being completely present in the current moment.
The poses (asana) are a way of using your body to practise mindfulness or mindful awareness.
Moving from one pose to the next helps you to be in the moment by focusing on breathing and moving in synch (which is so absorbing it doesn't leave much mental space to focus on worries or distractions). This is the mind/body connection.
After a while, this movement actually creates a form of mental stillness, because you no longer consistently get carried away with the never-ending monologue that's happening upstairs. Instead, you're just in the moment. Consider it a moving meditation.
For some people, asana is preparation for a more formal meditation done sitting or lying down. The yoga postures clear the body of restless energy so it's easier to focus the mind.
Eventually, all the practice at 'quietening the mind' translates from the yoga mat into the rest of your life, but it's a process. Like most things in life, consistency is key.
I'm not flexible enough
Fact: turning yourself into a pretzel doesn't make you 'good' at yoga.
One of the biggest misconceptions about the practice is that you need to be flexible.
You might be as mobile as the Tin Man, but if you're completely present with your breath, mind and body, then you're doing yoga. Your tight hamstrings have nothing to do with how you respond or react to the contents of your head.
In any case, there are many different levels of asana and most of them don't involve contorting your body into gnarly shapes.
Belief that flexibility is vital for yoga makes many think it's an activity better suited to women, who are often naturally more bendy.
In fact, men often benefit more from the physical side of yoga, because they're generally more prone to having tight muscles.
"So many men hate yoga because they think they can't do it," physiotherapist Anna-Louise Bouvier says.
But true yoga is non-competitive and a stiff person who gets small gains in flexibility from regular yoga practice is actually achieving more on the physical front than they give themselves credit for, she says.
"Not getting stiffer is actually getting better. If you can keep yourself the same as you get older, you're actually doing well."
Choosing a yoga class
It's a good idea to try some different types of yoga to see which ones you like best.
If you're looking for a workout, heated vinyasa or Ashtanga could be up your alley.
But if you're after something a little more chilled, hatha or yin might be more your speed.
When you're starting out, find a teacher who demonstrates poses and cues alignment clearly.
This doesn't always happen in more advanced classes, where students have been practising for a long time and understand alignment.
Also, in large group classes, it's difficult to cater to everyone.
Professor Marc Cohen, a medical doctor and complementary therapies researcher from RMIT University in Melbourne, suggests you always chat with the teacher before class if you have any concerns, to let them know you're a beginner or have specific problem areas in your body.
A good teacher will then suggest modifications to certain poses, he says.
He points out there is a "huge range" of standards in classes and teachers, and navigating this can be tricky. There might be some trial and error to find a good fit for your needs.
Challenge v pain or injury
Everyone is built differently with unique areas of weakness and tightness, so your yoga poses might look totally different to someone else's - that's normal.
In fact, some poses might not work for you at all. You never have to do every pose in class.
You'll feel challenged, especially if your muscles are tight.
But you should never feel pain, Professor Cohen says.
"If it hurts, what you're doing is not yoga. The idea is you just go to the edge of your comfort zone and just visit that. You don't have to push through any barriers or force anything.
"Just by going through your range of motion regularly, you'll naturally improve your flexibility. That's all you have to do."
Ms Bouvier, who specialises in treating people with recurrent injuries, agrees.
"People often see an increased range of movement as the end goal of yoga - 'oh I can move so much further, I can lift my head above my leg' or whatever - but it's not that at all.
"You need to really work on control [of your movement] using the breath as much as you work on range.
"I love yoga. I practise a lot of yoga. But I've also treated a lot of people with yoga injuries.
"So much of it is preventable if you understand every body is different and every day is different too."
One recent study found yoga caused pain in 10 per cent of participants over a year, although this is higher than previously reported levels of 1-2.4 per cent.
Professor Cohen says: "There are definitely advanced poses you wouldn't start out with - any of the inversions [where you lift your body upside-down] like a shoulder stand or head stand. You need to have very good balance [to do those] and they put a strain on your spine."
The Yoga in Australia survey, of which Professor Cohen was a co-author, also found lotus and half lotus (variations of a seated cross-legged position), forward bends, backward bends and hand stands to be poses linked with higher risk of injury.
Ms Bouvier says those who need to be especially careful when doing yoga include people with a history of back injuries, recurrent sprained ankles (which means they often can't do some sitting poses) or bad knees (which can make twists difficult).
While those who are naturally very flexible are often drawn to yoga, their flexibility actually increases the chance of them injuring themselves, she says.
This is because they can push movements too far and cause tissue damage.
"If you're already quite flexible, be mindful at the end range of any of the poses," Ms Bouvier says.
Also be careful not to let anyone adjust you into more extreme poses unless you are very experienced.
"I've had people be adjusted by a well-meaning teacher who goes 'look how far you can go' and they slip a disc [in their spine].
"Their muscles have let them go too far and the next line of defence is ligaments joints and discs."
However, she stresses adjustments from a teacher can be helpful and times when it goes badly wrong are rare.
Am I too old or unfit to do yoga?
"Like any exercise, yoga is not one size fits all," Ms Bouvier says.
For many older people, it can be "wonderful" but older people are also more likely to have had past injuries that might limit what they can do.
An older person who has practised yoga for years may be fine, but she is not sure if an 80-year-old should take up yoga as a beginner.
Alternatives could be tai chi or a gentle exercise class run by an allied health professional such as a physiotherapist or exercise physiologist.
Professor Cohen says his 84-year-old mother has been doing yoga for 30 years and she still does a beginner's class.
"She still does beginner poses but she does them at a more advanced level," he says.
If you are unsure if your health or age might make yoga risky for you, a seven-point questionnaire that makes up the first stage of the Adult Pre-Exercise Screening System can help you decide if seeing a doctor before you get active is likely to be necessary or useful.
Or you could seek advice from your GP anyway, which is often recommended for those over 40.
Can I do yoga if I'm pregnant?
The short answer is yes. But you'll need to start specific pregnancy yoga classes.
After the first trimester, many poses will be off limits. During pregnancy a hormone called relaxin is released, which relaxes ligaments, leaving you more prone to injuries.
So dynamic flows, back-bending, balancing and poses where you have a wide stance are no-go zones.
Plus, the bigger you get, the more uncomfortable most poses will become anyway.
Ms Bouvier says: "If you've always done yoga and then you get pregnant, the risk [of problems] is lower than if you start for the first time in pregnancy.
"You need to work on a gentler and more mindful practice when you're pregnant. And be very, very careful. Make sure you get a teacher that's very experienced."
Do I have to do the spiritual/mental stuff?
There are plenty of folk who only do yoga for the physical aspects and that's OK.
But others find once they start feeling the mental benefits, it makes them curious about exploring the other sides too.
Gone are the days where doing yoga and meditation require you to wear linen pants and leather sandals.
A modern-day yogi can be anyone from a corporate high-flyer who meditates in their office, to a student practising in their share-house lounge room.
If you're curious about trying yoga, but are worried you'll look like a confused mess during your first few classes, know that you definitely will.
So take a big breath and just own it - no-one but you even cares.
Before long you'll get the hang of it. Just like most things in life, we get better with practice.
The mental and physical benefits of yoga can be astounding, but they come with patience, consistency . . . and a sense of humour. After all, you are creating weird shapes with your body.