It could also be due to the way some insect musculature works, they typically don't have the same extension/contraction methods we have by pulling on either sid

It could also be due to the way some insect musculature works, they typically don't have the same extension/contraction methods we have by pulling on either side of a bone, which doesn't work in an exoskeleton. My understanding is that they instead rely on a combination of flexors and vascular pressure to extend which is a jerkier-looking process. See the muscle section here https://en.m.wikipedia.org/wiki/Insect_physiology https://en.m.wikipedia.org/wiki/Insect_physiology