long vs. short event training
I have a couple questions about training for long duration events versus short events. Most of my racing is short distance mountain bike events (10 - 15 miles, 1 - 1 1/2 hours). I entered an endurance mountain bike event in March (60 miles offroad), and I have been increasing my training distance for this event. This will most likely be my only long event this year, so I really don't want to hurt my short event performance by putting in too many "lesser quality" miles.
Personally I train for endurance mainly by doing long rides (Z2 - Z4), in contrast when I train for short events I do lots of drills, like hill repeats, ATI's, sprints, etc., with maybe one long ride a week. Have any of you found that by training for endurance that it hurts your short maximum effort performance? Most of my real training is done on the road, the mountain bike is for fun and technique.
TIA