Regarding the OP and MTB/XC-racing Zone Distribution, I did a race simulation this past weekend (with a full race warm up) on a trail that is in my XCO race series. I rode two laps of 100% punchy twisting singletrack. My first lap was 30:22 and my second lap was 30:44, so a pretty consistent effort. I would say I put in a pretty hard effort (95%), but not a full all out race effort. I took 2nd place (Cat 2) last year at this 1 lap race (TT style XCO race) with a lap time of 32:04. Side note, my second lap this weekend was 1:20 faster than my only lap on last years race day (thank you TR 
).
I have a power meter on my MTB now, so I’m finally able to analyze my outdoor and trail efforts. I was very surprised by my effort zones. It appears I was mostly either at endurance and below or in V02 Max/Anaerobic. A quite on or off effort with not a whole lot near the middle zones. Previously I would have thought my efforts (50%) were much more steady state (threshold), interesting to see I was way off 
. I may need to adjust my calendar to Short Power Build instead of General Build.
