Learning theories (ie: constructivism) are a set of ideas trying to explain how the process of learning happens. They have very little to say about what teachers should do.
For example, under constructivism, the learner either accommodates or assimilates new knowledge. That is, new knowledge is filtered through or compared against existing mental frameworks. *
This comparing/filtering happens whenever “learning” occurs. This comparing/filtering happens whether learners practice/drill, memorize, discuss, do labs, or any other activity that results in “learning”.
Importantly, if we accept that learners will compare/filter new information before it becomes new knowledge we can make some recommendations for how we should teach. For example, while drilling practice problems can result in learning, it doesn’t seem to encourage the comparing/filtering constructivism says is necessary. So, perhaps explicitly asking learners “how does this new strategy compare with your old strategy?” better encourages the filtering/comparing.
However, the difference in teaching strategy did not come from constructivism. Constructivism only has something to say about the learner.
*i fully acknowledge I’ve simplified constructivism here.