How do you modify yoga poses if you are injured or too inflexible or weak to do the pose in the same way that a flexible and strong yogi can?
Knowing how to modify poses can make it easier to improve flexibility and strength and the ability to do more advanced versions of the same pose. It can also mean that even if you aren't doing the advanced version of a pose you are still doing the pose the way that an advanced yogi might, with a body that is open, integrated and alive in the pose even if it is a modified version of the pose.
One of the first things to modify is your mindset. You might have the goal of doing the splits or touching the floor in a forward bend, but while actually working towards that goal instead of focusing on getting your hips to the floor in the case of splits or your hands to the floor (or your feet) in forward bend, focus instead on creating length. Make your body feel long and keep the length while working towards your goal.
One of the things that you miss being less than flexible is being able to use the floor as a support and this is where it helps to be smart.
For people who can get their butt to the floor in the front to back splits, the pose becomes easy because the floor is supporting the weight of their body. As a result their legs don't have to work. And so one way of simulating this is to use blocks under your pelvis and/or your legs.
If you can get your hands on the floor you can use your hands to help support your body. But if you can't get your hips to the floor you may also have some difficulty getting your hands to the floor and so here again the solution is to use blocks only this time use them under your hands.
With your butt on blocks you can lengthen your spine upwards. Additionally, if you are sitting on blocks, try pressing your legs down against the floor to lift your pelvis. Then smoothly relax and repeat.
With your hands on blocks you can press down with your hands to lift your chest. Then you can lengthen your ribcage and lumbar spine downwards and your neck upwards. Relax and repeat.
In either case notice the changes in sensation as you activate and relax.
Now splits is a bit of an extreme example, but hopefully it illustrates some ideas of how to use props to modify yoga poses.
If you have tight hamstrings a standing forward bend might be another challenge. You can't reach your hands to the floor. If you could you'd be able to use your hands to support the weight of your body potentially allowing your hamstrings to relax. So here again you can use blocks.
Press your hands down so that you use them to support the weight of your upper body then work at lenghtening your spine away from your pelvis.
What next? Try to gradually relax your arms. Relax them to the point that you can lift them. Notice the change in sensation in your legs as you do so.
In triangle forward fold you can do the same thing. If you hands don't reach the floor then use blocks. Press your hands down to support the weight of your body and lengthen your spine. If your back feels tight, because you are still bending forwards at your spine then use higher props and come up higher so that you can lengthen your spine.
Then try to relax your hands and lift them while keeping your spine long. Pause and then return to the starting position with your hands supporting your body again.
Do both actions slowly and smoothly.
If you don't have blocks can you rest your hands on your leg? Sure. Try stabilizing your leg against your hands. If your hands are on your thigh then press your thigh up agains your hands. Then as you relax your hands, relax the upward press of your leg at the same time.
It is a bit more tricky than using blocks but at the same time you can recognize that any time you press one part of your body against another you create a change in tension in both parts.
For triangle twist you might be able to do the same thing. But as well as pressing your hand down (and your thigh up against your hand) you could also try pushing away from the thigh or pulling towards it using your hand. See if either action helps your twist.
Note that for both triangle front bend and twist there is absolutely nothing wrong with doing either pose with the hands off of the floor. In either case keep your spine long, breath smoothly and with a relaxed breath.
One of the advantages of having the hands lifted is that your strengthen your legs, hips and spine.
If the hands lifted variation is too difficult then work towards it by first supporting your body and then smoothly and repeatedly lifting the hands. Make the movement feel breath like.
(Like a smooth deep satisfying breath that makes you feel good.)
For Warrior 1, you don't have to worry about getting your hands to the floor but if you've got tight hips you may find it difficult to get the front thigh level, the shin vertical and the hips square to the front. So shorten the stance. And widen it if you have to (to make balancing easier). And focus on lengthening your spine upwards.
If you repeat the pose a few times you can gradually work at increasing the front to back distance of your feet while keeping your hips square to the front. Or get your thigh level and then work at squaring your hips.
For triangle you can again rest your hand on your shin or thigh, press up against the hand, or place a block in front of or behind the leg and rest your bottom hand on it. Try both for a slight change in body position. And as with the previous poses work at doing the pose with your hands lifted. Why? so that you train the muscles that support your body in this position.
In side angle, if you can't touch the hand to the floor rest on your finger tips or rest your forearm on your thigh. But rather than just resting there push your forearm agains yoru thigh so that your shoulder is active and working to lift and support your ribcage. here again you can work at lifting the arm.
But even if you aren't doing that do work on making your spine feel long.
How do you modify a standing pose like half bound lotus? Standing pigeon is probably one good answer. Press your ankle down against the top of your knee. Another option is similar to a quad stretch. Here it's simulates the lotus in that you are grabbing the foot with a hand.
For poses like utthitta hasta padangusthasana grab a knee or use a belt to extend your reach. In either case make your spine feel long.
If you really like the idea of grabbing your foot try the same pose while lying on your belly.
Seated poses can be a challenge to modify.
For forward bending if you can't sit upright you can lie on your back with feet against the wall. Try pressing the wall and then relaxing. Or try pulling your feet away from the wall and then relaxing. Or sit with your back against a wall.
Another option is to sit on blocks, or better yet a slanted non-slippery surface like a sit up bench. Here you get the advantages of a more flexible person in that you can use gravity to help you stretch.
In a pose like compass prep use a strap. Make the leg long and of course make your spine long too. If found I progressed much quicker in this pose by starting with a strap, gradually working towards my feet. After a while (it may have been a month or more or less I can't remember) I was able to grab the foot easily without needing the strap.
Ideally you work towards the point where you no longer need props. Towards that end it helps to understand how to use your muscles within any pose or stretch. This means being able to relax muscles activate them and in either case feel them.
Also, if you are practicing by yourself, it helps a lot (I would say it is a requirement) to memorize your routine, or at least the poses that you want to use.
If you are working with random poses it helps to understand how they affect the body so that you can pick poses that help balance each other.