I ran the 400m in my final year of high school and had a PR of 51.2 automatic. That was about 14 years ago. I didn't continue training at all and have only played sports/jogged occasionally since then. Today I went out on the track for the first time in 10+ years and tried a 400 in sneakers with no blocks. I thought I was making decent time, but then I looked down at my stopwatch as I crossed the finish line and...68 seconds. I was pretty disappointed (I FELT like I was running a 58), but reading around on the Internet...I guess that time isn't that bad for a 30+ year old who is totally out of practice.
How quickly might I be able to get back under 60 and is it at all realistic to think that I could beat my PR at this age (32)? I didn't train very hard in high school and was more of a "natural" than a hard worker. I always felt like I had the potential to go under 50.
Lastly, what type of training routine would be ideal for getting back into decent 400m shape? I work during the days, so may only be able to run on a track on the weekends. Should I be starting out with speed work or endurance/cardio work as I try to get back into shape?