Almost as much is written about chaturanga on the internet as the amount of chaturangas you have to do in a yoga class. You could watch youtube videos about it back to back for days. Like a lot of modern postural yoga, it’s position in the wider yoga context presents a bit of a paradox.
Half the yoga teachers out there will protest that chaturanga is not a push-up, and the other half will refer to it as a yoga push-up.
If you’ve ever caught yourself wondering about it, I always think it’s a good idea to ask yourself the all important question: why?
For instance, why are you doing it personally? Why is it part of the practice that you’re engaged with in particular? Why has it become a staple of the yoga movement lexicon? And why does it have its current particular popularised alignment?
I can’t answer the first one for you. You’ve probably asked yourself that after the fifteen thousandth sun salute of whatever sweaty vinyasa class you accidentally wandered into.
In the rest of this article I hope to answer the other questions, at least tangentially if not directly, as we ask a more straightforward question:
What exactly are you meant to be doing in chaturanga?
What’s the big deal?
But the first question I want to answer is about this article. Why write it in the first place? There are thousands of hours worth of articles already written about chaturanga. Why add any more?
In the yoga community a fairly big deal is made about the alignment and potential dangers of poorly executed chaturangas. You have to search much harder to find anything nearly as dramatic about the dangers of doing bad push ups in the field of exercise science.
Here I’m using the term “yoga community” to mean my aggregated sense of people’s opinions on blogs and social media. So hardly a systematically derived survey, but you’ve probably heard it yourself or seen it online. Sometimes yoga teachers can be fond of catastrophising – I’ve seen more than one article referring to Chaturanga Dandasana as a “shoulder shredder.”
Perhaps you’ve even hurt your shoulder at some point and have held chaturanga to blame.
Why is that?
Is it because there are more injuries from yoga than from other bodyweight exercise systems? The answer is probably not, and some interesting articles have been written about the kind of cognitive biases that make us think there are. Like this.
Is it because too many people are doing chaturanga “wrong” or with “bad alignment”? Again, probably not, but it wouldn’t be surprising if that’s what you thought.
Most likely it’s a combination of completely different other things.
Yoga presents itself as a healing modality, and it is definitely capable of transforming people’s bio-psycho-social model of themselves.
Perhaps people come to it with the expectation that it can therefore do them no damage, they act carelessly, and end up hurting themselves.
Or maybe because of its image as having a great healing potential, there’s a higher proportion of people who come to yoga in need of healing. Yoga is often used for rehabilitation. People come to class with physical problems that they hope yoga will alleviate, but these physical problems make them more susceptible to injuries from some of the more challenging aspects of the physical practice.
**First the usual caveat with my use of the word “Yoga”: all references in this article are to postural yoga, in other words mat-based pseudo-calisthenics, whether or not the practice positions itself within a wider yoga context.
Even so, postural yoga is hugely diverse, and you don’t know what a practice will involve before you step into the class. This can mean you’re unprepared for the level of intensity of activity that you find yourself in. You can sometimes find yourself doing more chaturangas than you bargained for, and the group energy spilling off the mats around you makes you feel that you should do them all, even when you’ve reached your capacity.
So it’s probably got something to do with the reporting of the injuries that makes them seem worse. In other words, the difference between the subjective experience of the people who become injured and their expectations of what yoga is and what it can do.
There’s no such thing as a “Yoga” injury
In a paper published in the International Journal of Yoga Therapy in 2009 titled “Understanding and Preventing Yoga Injuries,” yoga teachers and therapists were surveyed on their opinions about what causes injuries in yoga practice. In answer to the question “Are there more Yoga injuries today than previously?” several respondents answered: “there could be no such thing as a “Yoga” injury, because properly executed, Yoga causes no injuries.” 1
This says a lot and is, of course, complete nonsense.
It says something about the prevailing notion in the yoga community that injuries are caused by doing something “wrong,” probably from not paying attention to what the teacher has been saying about “alignment.” In case you hadn’t realised, “these” are scare quotes. We’ll get to why in a bit.
Luckily it’s a notion that is beginning to go out of fashion. A greater level of scientific inquiry is being leveled at yoga, but tradition will always have an important hold on yoga and arguably will have an influence on the effect that yoga can have on those who practise it. And science and tradition don’t always get along. I wrote something about that here.
According to the results of the survey, the second most likely to be injured area of your body in a yoga practice are your shoulders, just behind the first-placed lower back. Top on the list of asanas that are frequently associated with shoulder injury was chaturanga dandasana.
So at least according to the unreliable recollections of yoga teachers, compounded by their experience of doing one too many chaturangas, the shoulders are an area of the body that needs to be red flagged.
Chaturangas of the mind
Yoga traditionalists are keen that chaturanga isn’t seen as a push up. Again, I’m grouping a diverse collection of unknown people together here as “yoga traditionalists” in an effort to gain some insight into the question rather than to just be divisive.
Why isn’t chaturanga a push up? Is it just a case of marketing?
Broadly speaking, there are two reasons why you might not want to see chaturanga equated with a push up, a psychological reason and a physical reason.
Psychologically, to class chaturanga as a push up, groups it with other “work out” activities, which puts it into a category where many believe it doesn’t belong. Traditionalists will say that yoga’s not a work out, regardless of the health benefits that practising yogasana might confer. They might say that in fact practising yogasana doesn’t even guarantee that you’ll be practising Yoga with a capital Y at all.
And traditionalists might well be right on that front. You can just be going through the motions. Everyone’s done it at some point. It’s possible to go through a whole practice in a disconnected way, thinking about how much you can’t wait to get back to watching reruns of the Real Housewives of New York City eating Doritos on the couch, and make no effort to alleviate the root causes of suffering in the world.
Yoga claims that this is one of its main purposes.
This somewhat avoids the issue that some people use yoga as a workout, and practise it exclusively for its health benefits, and leads to difficult questions about what yoga actually is, and what it can potentially do. And it raises even more difficult questions about whether you should give people a hard time for not trying to access the same effects from Yoga as you claim you do.
Naming is especially important. It can provide a framework for some complex and amazing processes to unfold, so to class the reason as psychological is not to diminish it. It’s best just to say on this front that it’s complicated.
However, it can mean that in order to justify the psychological reasoning that chaturanga is not a push up, claims get made about it’s physical execution.
Push your body up
The other reason that you might not want to call chaturanga a push up is physical. Is there something fundamentally different about how a push up is done compared to a chaturanga dandasana?
Is it not a push up because it’s done in a special non-push uppy way?
The short answer is no.
The slightly longer answer is that there are loads of different variations of a push up that you can do, and chaturanga happens to be one of those variations.
Of course, chaturanga is a static posture and a push up is a dynamic movement. However, chaturanga is usually practised as part of a sequence (often a sun salutation), and it’s unlikely that you’ll have a teacher that makes you hold it for very long. You do get some though. Just like you get some who sequence plank-chaturanga ten times, like you might do 10 push ups in a row.
There isn’t one standard alignment of a push up that you have to do in order to be doing a push up. Instead, exercise science recognises that when you change the position of parts of the body involved in the movement, then you change the load on the structures involved, and this can be done with purpose.
In a push up this might involve having the hands wider or narrower, leaning the whole body forward or backwards, changing the position of the arms or lifting limbs off the floor. All these changes will mean that the working muscles groups – in particular the pectorals, but also the deltoids, triceps and abdominals – have to work more or less hard, and you can adjust your body’s position based on a desired outcome to target those muscle groups.
The common myth is that if you have your hands wide it’ll work your pecs more and if you have your hands close it’ll work your triceps. However research has shown that this is just a theory that doesn’t match the data, and that in fact hands close works everything more than hands wide, except the biceps brachii which are activated more in the wide position.2
I couldn’t find any research on what the optimal alignment of a push up is.
Optimal in the sense that it causes the least injury for maximum strength and endurance gain. It’s not an idea that makes much sense anyway: changing the position of body parts just changes the activation of the different muscle groups. And for data on injury mitigation to be relevant, you’d need an enormous cohort at great cost to answer a question that people aren’t even asking outside of the yoga world.
The most official instructions I could find come from the Physical Fitness Test of the FBI’s Special Agent Selection Process. The hands are meant to be “one to two hand-widths beyond the shoulders and elbows must be away from the body,” and you go down until the elbows are in line with the shoulders.3
The FBI have got a vested interest in making sure their potential recruits aren’t injured in the fitness test – beyond the fact that people sometimes hurt themselves – so you could take this as a “basic” or low risk push up alignment.
Who chaturangaed first?
It would be good to know exactly where and when chaturanga entered the yoga asana library to have an idea of how exactly we’ve come to have the alignment that is currently taught on the internet and in yoga teacher trainings all over the world.
Not that it would mean that knowing when it appeared would mean that’s the “correct” version to practise, but it would provide a reference point to see how things have changed.
And would also encourage the yoga world not to see alignment as fixed, but rather a set of instructions that have changed over time based on changing understanding of anatomy and biomechanics.
The best we’ve got from the historical record are two pictures of Krishnamacharya doing chaturanga – both with different anatomical alignments – one of which he recommends holding for 10 minutes. Good luck with that. We’ll look at them later.
Whether Krishnamacharya introduced calisthenic elements like push ups into hatha yoga and where he got them from are subjects that are still up for debate. Sun salutations as a practise involving sequenced body positions probably weren’t invented by Krishnamacharya, and have some precedent from Tantra, but it seems likely that he infused it all with some of the latest gymnastics from Sweden.4
Make sure you get it right
It’s easy to think that there’s a “correct” alignment for chaturanga, that there’s a widely accepted position that your body should be in to be doing the posture right. I hope you’ve realised that I’ve been using scare quotes because I don’t think that’s true.
In class your teacher will have an opinion about what you should be doing with your shoulders, elbows and hips that they will try and impose more or less vociferously, depending on their personality and background. Likewise, if you’re a teacher, you’ll have an opinion based on your own teachers and the training you’ve undergone.
To cement it all in place, we’re now inundated with easily-shareable infographics of how to practise chaturanga with alignment cues which have become so widespread that they’re taken as a kind official alignment by many people because of the sheer volume.
Social media has made information much more readily available, which is great, but also harder to verify as quantity doesn’t necessarily mean accuracy. It’s easy to believe something’s right just because a lot of people are saying it.
This alignment isn’t necessarily “correct,” it’s just popular. It’s also not necessarily “wrong” either.
There’s almost certainly something wrong with putting lots of pictures of yoga postures up on the internet with big red crosses and green ticks on them, especially when you’re dealing with a practice whose effects are mediated by the thoughts you have about it… but I’ll leave that for a different article.
The reality is that just like doing a push up, there are lots of different variations of chaturanga, and they all have a different effect on the working muscle groups.
Popular chaturanga alignment
So if there is a popular chaturanga alignment, what is it exactly?
First another caveat – not all yoga teachers will teach it like this.
From a plank, lower yourself down by bending your elbows, without changing the position of the hips and spine. In other words don’t arch the lumbar spine or flex the hips. Sometimes it’s done in reverse – from the floor – push yourself up until you’re hovering, with the same tension throughout the body to keep the hips and spine in the same position.
Often two extra key cues are given:
- Don’t let the shoulders be any lower than the in line with elbows
- Keep your elbows close to the sides of your body
These cues are usually presented as being of utmost importance to the successful implementation of the pose, and there’s sometimes a third:
3. Make sure the elbows stack on top of the wrists
For instance, Jason Crandell, in this excellent blog post about chaturanga recommends the first two alignment cues as critical to keep the shoulder stable and safe during the posture. He backs this up by saying that this advice was provided by a shoulder surgeon which gives it more weight.
Now Jason Crandell runs lots of very popular teacher trainings, which means this kind of alignment cueing gets distributed across the world and further cemented as the “official” alignment of the posture, as more teachers tell more students, especially when they’re new to the practice. What you hear first often sticks for a long time.
Maybe it is because of the market forces that run teacher trainings that a movement as complex and context dependent as chaturanga gets boiled down to a few lines of instructions. Due to the exploding popularity of yoga, teachers have to be quickly taught how to teach the postures to what tend to be large groups of people, rather than one on one. In order to transmit the information efficiently, you’ve got to be succinct.
And yoga teachers want to keep their students safe. The shoulder is a notoriously unstable joint, held together by the interplay of muscle and tendon, rather than a deep bony socket like the hip.
However, “safe” is quite a loaded term, and keeping someone safe in a yoga practice might not be as easy a task as giving blanket instructions about how to perform movements might suggest.
Lowering down into chaturanga halfway, so that the elbows are in line with the shoulders prevents the shoulder from going into extension while bearing the weight of the body.
The hypothesis is that the tissues at the front of the shoulder might not be sufficiently conditioned in to withstand the greater forces they will be exposed to, and therefore might become injured in this range of motion. This might be especially true of the general population who often roll into a yoga class after a day of inactivity and low shoulder usage.
What’s more, the forces that the body is exposed to in a push up or chaturanga are relatively high: in the bottom position you’re supporting about 75% of your bodyweight. It’s 69% at the top of the push up, so it increases as you descend.
Preventing shoulder extension in the movement is also what the FBI recommends on their fitness test. They’re definitely not dealing with the general population: the participants want to become Special Agents, so could be expected to be at a higher level of physical conditioning. If they’re not going through the full range of motion, you might think that it’s a good idea for you or your yoga students not to either.
Of course the FBI’s fitness test also might just have a set of rules for a push up that allow for evaluation – they need a definition for what counts as a push up to be able to decide whether the applicant has performed one or not.
Full range of motion
Allowing the shoulder to go further than the line of the elbow in a bent arm position isn’t inherently a dangerous thing to do. If you stand a little away from a wall and put your hands on it, shoulder’s width apart, and lean yourself towards the wall until your chest touches, you’re unlikely to hurt your shoulders – assuming your shoulders aren’t suffering from any existing injury.
Your shoulder will go through pretty much exactly the same range of motion that they would go through if you were doing a chest to the floor chaturanga. If you’re worried by the idea of going through full range of motion in chaturanga, then this would be a good place to start.
The only way to condition the shoulder to withstand the forces that loading it with your bodyweight in extension might generate is to load it in extension. In other words, without going through the full range of motion in a push up or chaturanga, the tissues of the shoulder won’t adapt to their full potential of load bearing movement. This is a foundational idea of exercise science – the specific adaptation to imposed demands, or SAID.
You might be happy with that, and that’s fine – continue to practise or teach the limited range version of your choice.
At the same time, you’ve got to ask yourself why you’re practising the movement in the first place. That’s why knowing where it originated might be interesting. If it is a special movement, with a special alignment that has an special effect beyond conditioning the upper body, then the limited range of motion might be fulfilling a function beyond the scope of our current understanding of human biology. Then going through full range of motion might be bad for other reasons than you might hurt your shoulders.
It is possible. Unlikely, but possible.
Bridging the gap
On the other hand, if you feel that including a push up movement in your yoga practice or teaching might be good for building strength, then it would make sense to maximise the potential benefits that it can bestow.
However trying to get from wherever you or your students are in chaturanga now to a chest to the floor version becomes complicated.
Going directly from practising a half way down to an all the way down chaturanga might not be something that your shoulders like immediately, especially if you do a lot of them straight away. This might mean even if your chaturanga is stable and easily executed, you might need to regress to an easier version, like putting your knees on the floor at some point during the lowering phase to deload it.
The difficulty of teaching this in a public class is the variability in the condition of everyone’s shoulders. Some people are weaker than others. Some people have pre-existing injuries.
Quite apart from the fact that people often don’t like to do an easier version of something they feel they’re already good at, accommodating everyone’s level often means going to the easiest version. If you’re teaching a large group, you have to use the lowest common denominator – the version that everyone can definitely do – unless you’re really creative and excellent at multitasking. Which I’m sure you are.
For some people, the right level of this pushing movement might be to do it against a wall where the load on the shoulder is at a minimum, and then gradually progress to raised surfaces that you lower down to the floor.
The timescale is a problem too. In order for the tissues of the shoulder to adapt to withstand greater forces, they need to be progressively overloaded without greatly exceeding their capacity. That means if you want to get stronger you have to gradually lift slightly heavier and heavier weights – and this has to be done over a period of time, with rest to allow the muscles to recover.
This is critical and often overlooked.
One of the strongest narratives in the yoga community is that you have to practice, and you have to do it everyday. Some traditions give you a day off here and there, but most say that ideally you practise everyday.
If you’re doing a lot of repetitive movements like chaturanga, and trying to increase your body’s capacity to do those movements, you have to give all the tissues involved time to recover. That means not just the muscles, but the connective tissue as well. Tendons get stronger like everything else.
The rate of progression will be different for everyone. This can be challenging for your ego in your own practice as you might want to be progressing faster than you are. But it’s especially hard if you’re teaching groups: you can’t unilaterally move everyone onto the next progression after a set amount of days or weeks. Some people will take longer to adapt than others.
How low should you go?
In your own practice that’s up to you, obviously.
Hopefully given the information you’ve got so far, you can work to increase the overall capacity of your shoulder over time, so that weight-bearing through the full range of motion isn’t a problem. Eventually you might decide you want to increase the range of motion and put your hands and feet on a raised surface so that you can bring your chest lower than the line of the hands.
Of course, you might find yourself in a class where the teacher still strongly insists that you don’t let the shoulders go below your elbows and tries to stop your low chaturangaing. That definitely happens: yoga teachers can be belligerent sometimes and often like to think that their way is the “right” way.
Belligerence aside, yoga teachers are placed in a challenging situation: given the difficulty of accommodating a class of differing ability, for many teachers the easiest thing is to give the blanket instruction to not let the shoulders go below the elbow. It feels like a safe middle ground.
It literally is the “safe” middle ground of the posture.
The more vulnerable are less likely to hurt themselves and the rest aren’t left with an roundabout explanation of how it both might and might not be a bad idea to allow the shoulder to go into extension. It depends on the individual and a progressive approach to increasing load and range of motion should be taken. It’s taken me more than 1000 words to unpack it here, so good luck in a dynamic vinyasa class, the home of chaturangas, where attention span is often just five breaths long.
However, those with the capacity to go lower will gradually lose it over time if they don’t continue to do so. Adaptation goes both ways, and the tissues will get less able to withstand the multi-planar forces that the movement subjects the shoulder to if it is not performed.
And if you think that the magic of chaturanga is in the exact shape that popular alignment describes, bear in mind that Krishnamcharya demonstrated one version of the posture for his book Yoga Makaranda with the top of the humerus bone lower than the elbow.
Elbow your way into the posture
The question of elbow positioning is as much of a grey area as shoulder extension in chaturanga. Unfortunately questions of anatomy are never as straightforward and clear cut as the diagrams in anatomy textbooks or the instructions of yoga teachers might suggest.
The big cue of popular alignment is to have the elbow pulled in towards the rib cage.
If you look on the internet for the reasoning behind the instruction you’ll be hard pressed to find well-researched answers. Most internet based How-To guides which recommend keeping the elbows close to the sides of the body fall back on generalities: because the “alignment” is “safe,” and they don’t explain why. Some say something about the rotation of the upper arm bone, the humerus, but usually for the wrong reasons.
Some other voices are very anti-elbows close to the body alignment, and we’ll get to why that might be shortly.
To expand the generalities of the safeness, the idea is that having the elbows closer to the sides of the body will result in greater shoulder stability. Keeping the shoulders stable should be a priority during any movement of the shoulder, so this is a reasonable thing to suggest.
Just like with shoulder extension, if the humerus moves around too much in the shallow glenoid fossa, the bony structure which passes for a shoulder socket, it might result in damage to the tissues that provide the rest of the support, in particular the tendons of the rotator cuff muscles which attach to the joint capsule. If they are subjected to repeated forces which they can’t withstand the result is tissue degradation and damage. Or to use alarmist language, your shoulder might get “shredded.”
How would this elbow position actually contribute to stability?
The muscles which adduct the arm (bring it to your side) are the latissimus dorsi, part of the pectorals and teres major – some big muscles on the front and the back of the body. Actively trying to involve them in the movement by innervating the muscles would probably provide some support. In other words, a general increase in muscular tension is going to make the whole structure more stable, the humerus bone less likely to move around causing problems.
That doesn’t mean that you have to hug the elbows to the sides of the body though.
You can keep the arm adductors switched on without pulling the elbows all the way in, just like you contract the deltoids – the muscle on the side of the shoulder which abducts the arm – without making the arm bones fly out to the sides as far as possible.
It could be that the suggestion to emphasise using the lats (the pulling in muscles) is because the weight of the body will cause the arms to splay out as you lower down to chaturanga. Using the lats might prevent that. But what if someone’s already creating enough shoulder stability with the muscles around the joint?
How close is too close
One of the few instructions that the FBI give for their fitness test is that for a push up the elbow should be away from the body. Who knows why.
It could be to stop people using their arms as a support to rest on when they go down and cheat the test by completing more reps more easily. It could be because whichever kinesiologists or exercise scientists they consulted recommended a more neutral elbow position.
Overusing the lats might affect the position of the humerus in the shoulder socket. The origin of the latissimus dorsi goes all the way down to the top of the lumbar spine which means some of the pulling action on the insertion at the top end of the humerus will be down and away from the shoulder socket. This may or may not cause problems in the shoulder when it’s loaded in the chaturanga position.
Likewise the fact that the lats are also internal rotators of the arm. In fact all the arm adductors have that action as well, so pulling the arms in will tend to create a bit of internal rotation of the shoulder joint. This also may or may not cause problems for the shoulder joint when it’s under load.
The muscles that stabilise the joint – the rotator cuff – which also externally rotate the humerus are much smaller than the lats and the rest of the adductors. If the lats are being used to forcefully pull the arms in, the rotator cuff muscles can’t do their job nearly as effectively, or even at all.
So in the long run, it might be better to let the elbows go where they go, and work on strengthening the intrinsic muscles of the shoulder which will create more robust stability over time.
Again, that might mean working on an easier version for longer than you want or trying to convince your students to do something they think they can already do easily and are therefore ready to move on from.
The final piece of alignment cueing that is often given involves where the hands should be placed. Actually it’s the first piece chronologically in practising the posture, but I’m getting to it last.
You start with your hands directly under your shoulders in plank and lower down into chaturanga, often with the instructions that your elbow must be stacked above the wrist in the bottom position. You can see a good example of that in the picture of Krishnmacharya above.
If the hands are shoulder width, and especially if during the movement the elbows are pulled in to the sides of the body, the only way for this to happen is for the whole of the rest of the body to shift forward in space. Otherwise there’s not enough space for all the body parts to fit in. Often this is given as a key instruction in performing the posture successfully.
Shifting the body forward so that the hand position is lower down changes the loading pattern on the shoulder. A study from 2005 determined that this particular variant of a push up activated the pectorals more and the triceps less than having the hands in line with the shoulder.5 Depending on the individual, this could well make it a harder movement to execute, which might mean the stability of the shoulder is compromised.
Krishnamcharya seemed to be an advocate of this alignment. He has shifted so far forward that the palms of his hands are lifting off the floor. Eventually, if you shift far enough forward and you have the muscle power to hold yourself up, your feet will lift off the floor too.
Harder is better
Wrists under the elbows is not an alignment that I’d recommend for everyone, but that doesn’t mean it’s bad.
If you’re injury free and you’re strong enough to easily do a chaturanga with a little extra left in the tank, shifting forward to stack the elbows over the wrists might be a good thing to do. It’s a way to increase the load on the pectorals so that they adapt to a greater load bearing capacity in the future.
In other words it’s one of the methods that you can use for progressive overload in yoga asana. If you’re unwilling to bring in extra props like weights to your practice, it’s really the only way. You have to change the length and angle of the lever arms to change the mechanical advantage to one that favours more muscle fibre recruitment.
That means, like I said at the beginning, chaturanga’s a push up where different hand and body positions change the load on different parts of the body.
This article has looked at 3 points of popular alignment and discussed why they might be more complicated than they first appear – or that they might complicate your life if you’re a yoga teacher.
If you’re not sure in your personal practice what to do, then I hope this article has given you some ideas for experimentation with the movement which will benefit your shoulders in the long term.
What I haven’t covered here is what happens with the result of the shoulder in the movement, namely the scapula, so really it’s only a part of the story. The humerus attaches to the scapula, the scapula to the clavicle, and the clavicle to the rest of the body. How the scapula moves when doing something like a push up or chaturanga is an important part of the equation.
But I’ve spent more than 5000 words talking about the position of the arm bone, and that’s probably enough for now. How the scapula moves can be a story for another day.
- Loren Fishman, Ellen Saltonstall, Susan Genis, 2009, Understanding and Preventing Yoga Injuries, International Journal of Yoga Therapy
- Kim, Y. S., Kim, D. Y., & Ha, M. S., 2016, Effect of the push-up exercise at different palmar width on muscle activities. Journal of physical therapy science
- Mark Singleton, 2010, Yoga Body
- Marina K Gouvali, Konstantinos Boudolos, 2005, Dynamic and electromyographical analysis in variants of push-up exercise, The Journal of Strength & Conditioning Research