In general, you can divide yoga classes that you find into two categories. The first kind is more structural and technical. It may be derived from a particular lineage and will work to fine-tune the body in precise, anatomical ways. The class will actually seek to teach the practitioner how to hold new structure in their body and mind. The second kind is more of a flow class. It will likely feature much less technical detail, and the focus may shift to something energetic like feeling, imagination, or visualization. The pace will likely be more rapid as less time is needed to explain anatomy, and the practitioner is more quickly freed up to move in a way that feels personally organic. A rare third type of class is possible with a very skilled instructor - one that seamlessly blends dense theoretical knowledge, while maintaining a fluid pace. Ideally, neither principle will be sacrificed in the process.
I believe both of these practices are tremendously valuable for different reasons. It is my contention that a good deal of technical alignment should be learned before we attempt to proceed into a flow state. This is simply my method, not an assumption of correctness or best practices. Alignment and technical form serve to organize the practitioner. The world has a tremendous ability to disorganize the individual. First at the level of the body, which becomes injured and pained through overuse, simple degradation, or random incident. A slow and skillful movement practice can seek to realign and strengthen parts of ourselves that are underused, and relieve parts that are working too hard. Secondly, the mind carries stress, emotions, and trauma which make us sluggish, both inside and out. A wide variety of mindful practices aid in mental coherence, and facilitate a connection back to the Self. This is why a daily structural practice is incredibly useful to tending to both the body and mind. Most teachers I know engage in some structural ritual based on poses, breath, meditation, journaling, etc... There is no perfect formula for what each individual should do or for how long. Rather the goal is to keep being curious until we sink into a place of stability through our practices. Once a viable practice has been established, we can use it to access ourselves in a more profound way. This is where we step into synchronicity with the world. This is when we start to flow from that structure.
A flow practice that is embodied is a poetic experience. I believe this type of class to be much more advanced than anything structural. Something that transcends physical requires an advanced knowledge of the physical itself. Without that tangible component, our flow state will be lacking in integrity. Unfortunately, this is the most common type of class that we see. I think this stems from our desire to move into something pleasurable before we have the space to hold it. A less than ideal flow class features loud music, fast pace, and poor technique. This leaves the practitioner in a state of confusion rather than capability. It teaches the student to do the poses personally before they have enough information to decide what that should be. Once there is enough information, then conscious decision becomes possible and curiosity naturally emerges. Flow is a transcendental experience, but it will never reach that place if we try to move to it prematurely. Once you can move between shapes with equal parts for and grace, a whole universe opens to you. As you embody forms that are technical and therapeutic for you, a portal into the imagination opens. A gateway into ourselves is breached where we become divine creators. A place is reached where we have enough technical information to manipulate our Selves and, in turn, our realities. In this way, we can start to shape our worlds in any way that we choose. This is a real state of flow. When you have enough technique to glide, swerve, bend, and stand up to the world without shattering.
Contrary to popular belief, yoga is not a reclusive experience. It's not a place to hide in yourself while your problems fester and wait for you. Yoga is the courageous state that we achieve - to fully step into ourselves and promise to stride with the moments we are given in the world. To stride with the world does not mean that we simply take it as it is. It means we know enough to skillfully move with it, to be cunning and brave when we need to be, or to allow grace and acceptance when we need to synchronize. Eventually realizing that integration reconciles all strife. Embodiment dwarves all conflicts. There will never be a right or wrong way to act in the world. Spiritual practice only seeks to give us the tools to discern how to act for ourselves. A cause, belief, or creed will change as rapidly as the wind. If you've taken my class, you've surely heard more than one of my philosophical tangents. I am meticulous about avoiding world issues in my class and I'm happy to defend my position. Some of my favorite teachers enjoy discussing politics and the state of the world in specific ways. I don't mind if other teachers do if that is authentic to them. It is my belief that my beliefs are not relevant to your spiritual practice. It is my desire to convey the yogic concepts without coloring them with my personal views. Lastly, I don't want to manipulate anyone's viewpoint with the justification of yoga philosophy. Take ahimsa for example - the foundational practice of non-violence. That is a teaching that will be interpreted vastly differently by each individual. It's not in the scope of yoga to tell you how to interpret the teachings. In fact, many of the yogic texts are incredibly vague. They only become specific through modern interpretations and personal agendas. I'm not saying these agendas or angles are bad, but they are personal. I believe my role is to simply convey the teachings as I understand them, without a great deal of personal application. This is why I won't say to eat a vegan diet as a form of non-violence. I will simply say to do less harm than you did yesterday, in any way that is meaningful for you. Open and gentle teachings are much more impactful than dogmatic ones. Dogma creates resentment and stifles the creativity of flow. The role of the teacher is to allow their student to blossom as they will. Provide guidance and pruning when necessary, but ultimately to allow their safe and prosperous growth.
The alchemy of alignment and flow is the desired state for the yoga. One that is structured enough to hold them upright and one that is fluid enough to move them through the world. To quote Alan Watts: "A holy person is one that is whole: who has reconciled two opposites and so there is always something scary about holy people." They can't be swayed by one side or another because they have seen both ends and have thus seen the middle.