Upward facing plank ehh? Sounds like it will be good for me to go look that up, though it is probably what it sounds like. Hopefully my shoulder can take it I also have pec issues (both major and minor), and it would likely be good for those as well - as long as it doesn't cause numbness (major thoracic outlet syndrome)
Thankfully my little hamstring tweak appears to be gone, I had walked quickly for 5 minutes the other day before I started running on the trails, I suspect that wasn't enough in 48 degree temps. What do all of you do to warm up before running in cooler temps?