Almost a year ago I did the V02 max test, Lactate Threshold test and Max HR test to help accurately establish training zones. At that point I had been training for about 1 year. I am now 29 years old and have continued a steady training program. Planning 400 hours this year up from about 340 last year. I was just wondering if there is any rule of thumb with regards an increase in physical fitness and changing training zones. I can provide more details if I can get a better answer. I can also get retested if that's the best way but I wasn't planning on doing that again until the season is finished. Thanx.