WOW. Ever read Daniels' Running Formula? Many of you guys need to read up on the difference in physiology between the 13.1 distance and a 5K. It's all about duration. Lagat has never raced for longer than 13 minute 5Ks until now. For him to go from that all the way up to almost FIVE TIMES as long is VERY DIFFERENT. First, there's this thing called Lactate Threshold-the pace you can maintain all out for 1 hour. For Elite Half Marathoners, the lactate threshold is their 13.1 pace(or very close to it).
VO2MAX is a pace one can hold for about 3000-5000 meters. VO2MAX(Interval) Training is most important at these distances(in contrast to lactate threshold). 1500m racing relies on VO2MAX but also some pure speed/anaerobic power training. Threshold work really doesn't become important in training until you get to the 10K and beyond.
To put things into perspective, Lagat's best races have been 1500m-3000m, relying heavily on VO2Max and pure speed training. Maybe he will do some threshold work, but it wasn't the PRIMARY workout NEEDED to PERFORM as a top 1500m-3k guy. Even as Lagat jumped to the 5K, he was still focusing primarily on VO2MAX(Interval) training.
Again, once the duration gets closer to an hour, lactate threshold training becomes more important. Again, as I said before, Lagat's BEST races have been in the 1500m-5K range. I believe that every athlete has a range of where their best events are. Some are just freaks all around(Gebreselassie for instance still busted out a 3:40something mile). But you could tell that Geb was a dominant runner in the 10K, which I believe was his best event. Yes he ran 2:03:59 or whatever for the marathon, but I believe 26:22 is a stronger performance. This was Geb's prime. So for Lagat, the half marathon probably is getting close to the tail end of his "range." Ryan Hall is another example(but also I think Hall SHOULD work on his speed more) of someone who is a prime marathoner and not really a 5K guy. Compare Hall to Lagat and you will get near opposite runners in the distance running world.
Do I think it's good Lagat is racing 13.1s now that he is a bit older? YES. Do I think he ran very well on Sunday? YES.
1:02:33 is an outstanding performance if you look at how far he had to jump.