I really have to start scheduling anaerobic endurance. It's one of my limiters I'm sure. When I ran off and on for a year I got a 20 minute 5k but only 1:17 400 meter. That's not an amazing 5k, but it's a pathetic 400 meter. I feel I have the same issue on a bike. 10 seconds or 20 minutes no problem. 1 to 5 minutes is agony. Do you guys do this stuff in base?