Looked like he fell onto a tire tool

Or maybe an axe handle.

Residents subdue fire suspect by tying him to a tree.

From Oregon Live

In part: “An ambulance crew was asked to respond due to some injuries that the suspect apparently received from falling down.”

https://www.oregonlive.com/wildfires/2022/07/oregon-man-who-started-wildfires-ends-up-tied-to-tree-by-locals-sheriff-says.html

Link at knuckledraggin