Compression socks are great for ultras for me. There are lots of gimmicky things that manufacturers attempt to purvey. Essentially there are two biological reasons why they can help. Firstly, the legs can pool a lot of blood in the viens, obviously deoxygenated and raring to deposit its CO2 back into your lungs to breathe out. The veins can only work as quickly as the blood pushing it through the system. Constrict the size of the legs by means such as compression socks and prevent the lumen of the veins from expanding and thus less volume of blood is pooled before being returned back up. There is also the issue of support and prevention of muscle vibration which might reduce trauma and prevent any micro-torn muscle cells from filling up with tissue fluid. I've got a pair of £15 which I have used on 40+ ultras and change them every year or so when the elastic goes a bit. Finally, good to stop your legs getting too cut up and stung on cross country races. Good luck
I did the Norman Conquest 50 last month and came joint 2nd. This is the first year that Saxon Shore ultra trails have run and there were a couple of issues around checkpoints.....hopefully these will have been ironed out as the first 4 of us over the line gave some developmental feedback.
The trail routes are awesome though and the scenery at this time of year will be ace too. Bank holiday weekend...bound to rain! Make sure you kit well for this event and take plenty of food.