After my 1st very slow 10k race last night, I am determined to train to get a faster time next race, but how. Intervals, fartlek, hill training, how often. I tried to keep a mental note of my HR during the race, it was 165-170 on average, higher than my training runs at 150-155. Also I am tensing my shoulders and end up with the muscles in between my shoulder blades aching, which I'm sure affects breathing, as it has been pointed out to me that I'm not releasing enough air from my lungs. If anyone can suggest any literature worth reading that would help, or breathing exercises it would be appreciated.