I've been carrying a gun while running for at least 17 years. My mode of carry was an uber-cool fanny pack. My usual carry gun was the trusty G20. When I graduated to longer runs (4+ miles) I needed something lighter and less obvious. I found this http://content.yudu.com/A2r1cj/PoliceMarksmanSO2014/resources/index.htm?referrerUrl=http%3A%2F%2Fpolicemarksman.com%2F (http://content.yudu.com/A2r1cj/PoliceMarksmanSO2014/resources/index.htm?referrerUrl=http%3A%2F%2Fpolicemarksman.com%2F) a few years ago and have never looked back. Page 26.
I'm no affiliated with the company.
A glock 42 380 would be my choice, but since I can't run anymore the G29sf with 15rd clip with adapter stays with me for my more sedate walking trips. ;D
Doug
I can't run, but if I could, it would be a in a belly band rig. Since most of my running would also be wilderness trails, any compact poly framed gun in 10mm or .45ACP would be what got carried.