I cannot run faster than 9 kph on the treadmill because everytime I do I get a pain in my lower back on the left hand side.
I've been running for the last 3 or 4 weeks approx 2-3 times a week and it isn't getting any better. I'm trying to get to 12 kph.
How can i prevent this? My warm up is just a 3 minute walk. My trainers are quality running trainers.