Basic ballet positions, technique and movements are taught through barre exercises. To discover and increase your turnout, and improve your natural dancing abilities, you need to understand the purpose of each barre exercise. Adult ballet beginners can progress faster with an understanding of ballet barre work.
A ballet barre work out is designed to warm you up while working different muscle groups.
For example, the demi (half way down) and full plie exercise warms up everything a little, but more so for the large quadriceps (front thigh muscles), gluteals (butt and hip muscles), as well the supporting abs and back muscles. But, mainly it's thought of as a leg exercise.
As you advance, different arm movements are added, to practice ballet positions of the upper body. It also requires coordination and musicality to do the arm positions and movements.
However, if your class doesn't do a lot of arm positions in plies, don't worry. Your teacher is giving you a chance to concentrate on your legs, posture, and turnout until you get stronger.
Battements tendus and degages are mostly lower leg and foot exercises. This gives your upper leg muscles a rest, although all your muscles will support the technique you are building with the footwork. Maintaining good posture and turnout is crucial here, as in every ballet barre exercise.
A well-planned barre continues with trading off on larger upper leg muscles with lower leg and foot muscles, as you proceed through it. This way you get practice, you get warmed up, but never exhausted.
Technically, a ballet barre exercise may work a set of muscles "to exhaustion", which means you may experience a weakness, or trembling by the end of the exercise. THIS IS GOOD! This point is where your brain tells your body to build on the size of your muscle fibers, meaning, building strength.
And again, a well planned barre will then rest those muscles and work others in the next exercise. This is all carefully planned for you.
In a ballet for adults class, ask questions when you need to. Keep a small notebook so you can write down ballet positions or movements you'd like to look up after class. You'll master your barre exercises and enjoy ballet that much more.