You Need A Good Teacher
Please be careful with the teachers or fitness trainers you choose to follow. Group fitness instructors, yoga teachers, pilates private teachers, fitness running buddies. You need to be able to understand the good from the not so good.
There're two different types of the not so good ones. The ones who are fitness oriented, they studied, they live fitness but they can't transmit the knowledge either because they can't be bothered or because they're not made to be teachers and so they don't know how to do that. And then there're the self-proclaimed teachers (of all kinds) that maybe they did a short training of a month or they just want to get a piece of the fitness and wellness pie and follow the hype. They do the minimum, they don't practice what they preach but they do preach a lot. And they're loud. And Instagrammable. In general, self-proclaimed teachers of anything are the worse sort. Because you don't trust your body to someone who doesn't know what to do with theirs. You don't trust your body to someone who can't tell you what will go wrong if you do the exercise wrong or if you use the wrong muscle group. So I'm not going to talk more about the non-teacher preachers. Do your research and don't follow any hypes.
I want to talk about the good teachers, the ones that don't always know how to pass the message. Understandably teaching a large group of individuals, a barre class or Zumba isn't the easiest thing, in the sense that you can't be there for everyone, you can't monitor everyone. But there're still things you can always say and show to students to make them understand the movements they shouldn't do. There's a big difference between the movement you can do with less effort and the movement you shouldn't do the wrong way. Students need to know what will happen if they do something the wrong way. Say, "If you don't engage your core you'll get a back injury." That's it, make it clear. I learned how to engage my core the right way just because of a very good teacher.
There are many good teachers but choose an excellent one. It's this excellent teacher that will motivate you to go on, it's this excellent teacher that will make you understand how important warming-up is, it's this excellent teacher that will give you options and variations, it's this excellent teacher who will guide you to be yourself.