Questions & Answers about Мы отдыхаем, не надо делать лишние движения.
Why do we use the imperfective делать here instead of the perfective сделать?
This is the main rule for negative obligations! When you say an action is unnecessary using не надо or не нужно (no need to / shouldn't), you almost always use the imperfective infinitive. Even if you mean "do not do this one specific thing right now," the imperfective делать is required to express that the action shouldn't happen at all.
What case is лишние движения in here? It looks like the nominative dictionary form.
It is in the accusative case because it is the direct object of the verb делать (to make/do). Since движение (movement) is an inanimate noun, its plural accusative form looks exactly identical to its plural nominative form.
Why does the adjective лишние end in -ие instead of the typical plural ending -ые?
The word лишний (extra/unnecessary) is a soft-stem adjective. When plural inanimate nouns are in the accusative or nominative case, adjectives with soft stems take the ending -ие rather than the hard-stem -ые you see in words like новые.
Is делать лишние движения mostly used for physical movements?
Not at all! While it literally means "to make extra movements," Russians use it very often as an idiom. It means to make unnecessary effort, create a fuss, or overcomplicate a situation. Here, they are basically saying "we are relaxing, no need to do anything extra."