Before the advent of the Yoga Alliance and teacher training programs, you learned how to teach by practicing & observing a senior teacher. This is still the most effective way to learn. Using a teacher training manual to teach is like being dropped in Brazil with an English to Portuguese dictionary. It helps, but you don't master the language or the yoga until you fully submerse yourself in the culture.
Like many high school and college students, I took two years of French. My High School French teacher admitted to us that even with her degrees and intensive study, when she went to France, she could get around okay but she definitely could not carry on a good strong conversation. Her French was extremely basic and formal and she could never make a strong connection with anyone while using it.
The same goes for teacher trainings, workshops & occasional yoga practice. You can definitely teach a basic well rounded class but it is hard to fully connect with your students because you really have no clue what language is being spoken in the real world of yoga. All you have is theory. If you only plan to teach in gyms, churches, and do corporate gigs, that will work. If you plan on actually going to France where everybody knows the language, ie, teaching in yoga studios or amongst people who already have a strong background in yoga, you have to take your knowledge deeper. You need some "street cred".
Yoga teaching skills you can learn just by regularly attending a good teacher's class:
How To Teach a Particular Style
How To Do Adjustments/Assists
Sanskrit
How To Pack a Class-If you have a person in your studio or town who consistently packs out a room, you should definitely attend their classes regularly & see if their is anything they do that can be incorporated into your own style in an authentic way
Alignment
Chanting
Pranayama
Sequencing
Yoga Sutras
For more information on learning through absorption, Read this article
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