John, I was born to be an engineer. At the 11+ exam it was decided that I should go to one of the experimental Technical HSs and I haven't really look back until recently when I started to draw for the first time. I live in an area where a lot of people run but not seriously so it is not what I would call competitive. It is a small town on the outskirts of Ottawa. I upload my runs to GarminConnect to share with my running partners. I created a number of segments on GarminConnect just so we could rank our runs among ourselves. I was shocked to see how many other runners showed up in such a small town. The implication being that they all had garmin devices. On one route 41 other runners popped up. It would appear that most regular runners must carry some kind of device. I rarely look at my watch while I am running, I run by feel most of the time. I do find it fun afterwards to analyse how my workout went as you obviously have picked up on.
A 10 sec improvement is always worth having I would bank that. How can you tell what your effort level was compared with your previous PB. Obviously if you worked harder you are going to be faster.
In my most recent serious race in Dec 2014 before my knee injury, I got the following numbers
Duration Kms Miles Per Km Per Mile Cadence Slength(m) 22:16 04.7 02.9 04:42 07:34 87.3 1.22
As you can see my cadence is a bit low and my stride length is a bit high. Assuming I was overstriding and not very efficient, I could have achieved the same pace with less effort by reducing my stridelength and increasing my cadence only modest amount.
Ok I think I have exhausted that topic, it is a good job it is a rest day and I have no chores to do.