I just completed my second marathon but am very dissapointed. I had this sensation for a second time during the race where me legs from the waste down were in excruciating pain. It actually felt better to run than it did walk (which is why I finished the race) but as soon as I stopped I could barely stand up the pain in my legs was so bad. About 30 minutes later it started to subside and then completely went away. I am frustrated and confused because it does not appear to be an injury at all but just kind of starts progressively getting worse at aobubt the 30-35k mark. Anyone have any experience with this? Appreciate any advice!