Pearse There are some free skeletons out there, For example this one: https://sketchfab.com/3d-models/imnh-r-997-anteater-and-anth-90-41-human-200786ba55a148ac9a28040228ba0a13 But it's harder to find muscles, If you have a copy of zBrush there is a full skeleton and muscle in the projects folder I think. But to be honest sketching out the muscle shapes is a good way to get to know what they are doing. If you have the money Ziva also have a human skeleton with muscles for $110.
world3d99 Pearse You're absolutely right. I should learn to do it. Anyway, I have to practice it myself in order to master it fundamentally.
kishchris world3d99 U can also download Zeke, Lila and Mr.Ink from store great assets to learn ZivaVfx.