overtraining is always one of the biggest questions people ask. but really overtraining comes from riding 5+ more hours per week than you normally do for a few weeks, like if i normally train 15 hours and then i started training 25 hours + races for 3 weeks i would start to feel the effect. and also take into account that thouse 25 hours whould probably be alot of speed training and "fast" endurance, not just simply training for your first tri, plus your riding 6 days a week so on the 7th day you get a total rest day.