Speed workout

I did my first track workout today.  I ran an 8:30 warm up mile and then a little stretching.  My goal pace was 1:39 to 1:43 for each of four 400m runs with a 60 second recovery between each interval.  I ran a 1:18 first 400m at what felt like a pace a little slower than I could force myself to run a complete mile.  I am still very suspect of the 4:25 mile I ran in my neighborhood, but after running the 1:18 400m without really hurting, I'm a little less suspect since 1:18 400m is 5:12 min/mile pace.  Realizing that I ran the first one too fast, I tried to run a slower one and ran a 1:28... too fast.  I tried to run a little slower on the third 400 and ran a 1:45... too slow.  On the last lap I ran a 1:34... too fast.  After my 400m intervals, I walked an 800 and prepared to run a mile time trial.  However, my legs were shot.  I ended up bailing out when the first 800m was 3:28.  I already know I can run a sub 7 :)  My legs actually burned for the first time since I ran the mile all out a month and a half ago.  

I can run pretty fast for a soon to be 32 year old weekend athlete, but I don't have endurance.  I feel like I could run the 400 in around 60 seconds all out right now, but that's not exactly world class speed.  This was a fun workout and I hope it helps me sustain the speed I apparently was gifted from the good Lord.  I can see how the track can help you learn even pace running.

Stats:

3.5 miles of running and walking

Fastest 400m: 1:18

Slowest 400m:1:45

Average 400m: 1:31