Whenever i descend i'm prone to cramp, i think, in my diaphragm. It could be in the guts but i think it's diaphragm related because breathing gets painful which is inconvenient, so painful today that i had to stop to bend over in order to ease it and lost time, i had to finish the rest of the run at a reduced speed until the terrain levelled out then it went away more or less.
It's definitely only when coming down and every step feels like i'm being stabbed. Any ideas? cheers.