My former employer issues the Serpa. They've not (yet) had any leg injuries. Funny story is that I took it to an IDPA match shortly after signing on with them. Last stage required crawling out of a pup-tent. I apparently touched the ground while coming out of the tent and found the release button locked solid. Took it home and after some vigorous tapping dislodged a stone about the 2/3rds the size of a grain of rice. Went with an ALS/SLS from there.