Research has shown that constraints cannot only hinder, but also foster creativity. Nevertheless, it may sometimes be necessary to ‘stretch’ constraints so that creative processes can unfold. Studying the performance of classical music in two of the leading orchestras in the world, offering us examples of an extremely constrained context, we show that at least three different kinds of constraints matter in this context: aesthetic, material, and organiza¬tional. What is more, we show how these constraints are stretched, helped by engaging in different kinds of side-projects, which break out of and back into the main project.