I am a 53 year-old male, active cyclist, 5'9", 165 lbs.
Occasionally, right after vigorous or sustained exercise lasting 1-2 hours, I will experience intense cramping only in my lower left side while urinating.
This is never accompanied by pain in the ureter, odd-smelling urine, or weak stream. The pain is also never sustained and ten minutes later I am feeling fine.
No signs of kidney infection, bleeding, nausea, etc., just an intense stabbing pain on the left side of my lower back.
Not worried about it, but would like to find out how to prevent it.