Any ideas what the cause could could be? No matter what the intensity, regardless of uphill intensity, have been gettin sidestich pain running downhill. Why?
Sidestitches continue to be a nemesis for me. I have found that paying close attention to my breathing pattern helps. I found that I was exhaling on right foot strike which is know to facilitate stitches. By switching to breathing out (exhale) on the left foot strike I keep them away.
Jack Daniel’s PhD notes that 5k - Marathon breathing cycle correlates with six steps. So every six step you should be exhaling.
The other thing, my stitches tend to occur when I’m pushing beyond my fitness level (Running faster than I really can).
BarryP has written about this topic. A search on ST can reveal more info.
Hopes this helps.
chiro18