Most of the yoga stretches that I do are designed to improve flexibility.
One of the most important types of yoga stretches for improving flexibility is relaxed stretching. In this type of stretch the focus is on relaxing the muscle being stretched. This tends to stretch the connective tissue within the belly of the muscle.
Because the focus is on relaxing, I would not recommend this type of stretching as a warm up unless you include some sort of bridging exercises that reactivates the muscles that have just been stretched. As an example of reactivating muscles just stretched, in our Chi Gong class, after doing a wide leg seated forward bend (with a focus on using it to stretch the inner thighs) we use inner thigh strength to quickly bring the legs back together again. This action, of "clapping" the legs together helps to reactivate the inner thighs.)
For most relaxed yoga stretches gravity can be used to provide the driving force for the stretch. However, if grabbing an arm or a leg, or using the floor for leverage, you could also use the opposing muscle to create the stretching movement.
As an example, in this set of shoulder stretches, there are gravity assisted movements as well as muscle assisted movements for stretching the arms and shoulders.
Most of the leg and hip stretches that I use are also mainly gravity assisted. (hip stretches, hamstring stretches, seated hamstring stretches, hip flexor stretches, psoas stretches, psoas-stretches part 2, quad stretches and inner thigh stretches.)
Note that with gravity assisted yoga stretches you have the option of gradually moving deeper into each stretch. Instead of moving straight into each stretch, focus on moving gradually into position. Where possible I've included options where it is easier to control your body so that you can move into and out of each position easily and comfortably.
Resisted stretching is where you keep the muscle you are stretching active. And it stays active as you lengthen it.
Using the same yoga stretches, you can focus on resisting the stretch by activating the same muscles you are trying to stretch. As an example, in the chest stretch shown below, you could relax the front of the shoulder and let the butt cheek on the opposite side of the body slowly sink down to the floor.
It'll take time to sink down and your focus, meanwhile, can be on looking for the tight spots in your shoulder (and waist and ribcage, since this is a twisting stretch for the spine as well as a stretch for the shoulder.)
The resisted stretching alternative is to press the arm down into the floor as if trying to roll out of the stretch. However you press down with just enough pressure to give some resistance without actually coming out of the stretch.
Assisted yoga stretches are where you use the muscles that oppose the muscle being stretched.
As an example, in the above chest stretch you could use the muscles at the back of the shoulder as it trying to lift the arm off of the floor. (Note that the pose is already assisted by gravity. You could use gravity to assist a stretch or you can assist a stretch using the opposing muscles.)
In combined resisted and assisted stretching the idea is to activate both the muscles being stretched as well as the muscles that oppose the muscles being stretched. Using the above shoulder stretch, after pointing your knees up to the ceiling and starting to sink your opposite side hip, you could resist the stretch by pressing the arm into the floor. Then at the same time activate the muscle that opposes the muscle being stretched.
In this case think of using the arm muscles that you could use to lift the arm to instead roll the ribcage deeper into the stretch.
So that you move in the direction of stretch (in the direction that stretches the target muscle) make the muscles that assist the stretch stronger than those that resist the stretch.
A stretching technique that I often use with beginners is to focus on activating and then relaxing the muscle being stretched.
Again using the above stretch as an example, you could press the arm into the floor to resist the stretch and then relax it. I often teach this method in sync with the breath. And so you could inhale and resist the stretch and then exhale and relax deeper into the stretch.
I normally associate exhale breaths with exhales, hence the focus on relaxing while exhaling. However, you could try the opposite and exhale while resisting the stretch and then inhale while relaxing.
Yoga shoulder stretches includes traditional yoga shoulder stretching positions like reverse prayer, eagle pose and dwikonasana, the shoulder stretch used in prasarita padottanasana C.
For deeper shoulder stretching you can try this selection of gravity assisted and muscle assisted Shoulder stretches.
This can mean muscles like the adductor magnus long head are affected (since it can extend the hip), as well as some fibers of the gluteus maximus.
If your hamstrings are very tight I'd recommend using these as a warm up.
These hamstring stretches teach you how to stabilize the leg both when standing and seated so that it is, ideally, easier to stretch the hamstrings and improve their flexibility.
I've included different types of seated stretches for the hamstrings in seated hamstring stretches.
For active hamstring stretching you can learn to use your hip flexors.
Hip flexor stretches work on the front of the hip. These yoga stretches may be useful as warm ups or compliments for quadriceps stretches.
The psoas is a hip flexor (and a lumbar stabilizer). To stretch the psoas major effectively it can help to understand the anatomy of the psoas major. This anatomy lesson looks at how the psoas connects to the 12th set of ribs.
One method for stretching the psoas includes learning to add "inner tension" to the lumbar spine. This is covered in psoas stretches. Another technique for stretching the psoas is to keep the abs engaged, in particular the obliques. This is covered in psoas stretches 1.
Front to back splits is both a hip flexor stretch and a hamstring stretch though with the torso upright the focus is more on stretching the hip flexors (and psoas) of the rear most leg.
In general yoga stretches for the quadriceps all involve "closing" the back of the knee joint.
Easier quad stretches are those where the hip joint is bent forwards (flexed hip stretches) while more challenging quadriceps stretches are those where the hip is bent backwards (extended hip stretches) such as in reclining hero pose.
While it may not be possible to stretch the actual Iliotibial band (also called the fascae latae), you can stretch some of the muscles that work on it (fibers of the gluteus maximus, tensor fascae latae and vastus lateralis) with shoelace pose.
In general these glute and piriformis stretches include an external rotation of the thigh relative to the pelvis with a forward bend.
One of my favorite glute stretches is screaming pigeon glute stretch.
These yoga stretches are mainly stretch the inner thighs but also include poses where one or both legs are internally rotated.
Inner thigh stretches work on the adductors, the muscles that pull the legs inwards. This includes the adductors brevis, longus and magnus, pectineus, gracilis and perhaps also the psoas and iliacus.
For those with limited flexibility it may be useful to use a wall to make increasing flexibility easier.
In these yoga for flexibility stretches it is easier to put your body in a position where you can either use muscle power or gravity to take you deeper into each stretch.
These lower back stretches include a variety of standing and seated yoga exercises for increasing the flexibility and control of the lower back muscles and hip muscles.
Some of the exercises are actually strengthening exercises but they strengthen the muscles while they are lengthening.
Yoga stretches for body different body parts can be paired as follows for structural balance:
For arm and shoulder stretches,
To recover from "relaxed" and deep yoga stretches I'd recommend finishing hip stretches with balancing on one foot poses (while working on stabilizing the hip joint) or any standing poses where the focus is on activating the leg muscles.
For arm and shoulder stretching recovery you can use arm strengthening yoga poses including arm balances, yoga push ups, chaturanga dandasana, table top, bridge pose and reverse plank. You may find that wheel pose is a good way to recover both from hip stretches and shoulder stretches.