A beginner lacks coordination and they are usually extremely tense.
Their body is yet to do what they want it to do.
Tension prohibits free movement.
The solution to this is to focus on learning simpler movements.
This is why white belt and yellow belt focus upon qigong, and orange belt is mainly about section 1 of the tai chi chuan form.
When your body lacks the basic skills, there is a danger of injury.
You may hurt yourself.
You may harm somebody else.