Lack of power today, no kick in my legs. Endured 20 km's thanks to willpower. Some days are just tougher than other, but I also know that after a run like this, it can also be better then ever a week later. It's often a signal saying, that it's time to take a break and right now (a week before the ½ IM) it's actually time for tapering. Dave Scott's tapering plan over 21 days (divided by 3 in this case) can be recommended http://www.active.com/triathlon/articles/countdown_to_an_ironman__dave_scott_s_21-day_tapering_plan.htm?act=EMC-TriWeekly2_0808§ion=Articles&creative=Article2Link