On occasion I do wait until I am a day or two or even hours out from a key workout before settling on its format. Other times I get ideas a few weeks early. For example, at a relatively early point in a training cycle I might get an itch to do one of my favorite workouts, a 10 km relaxed (or 95 percent effort) time trial, but knowing that I am not quite ready for it, I mentally plan to do it three Tuesdays from now. The dimness of my path forward in training is never stressful to me. Seeing miles ahead is of little value if you have little reason to believe that you will actually be able to stay on the path you see. While relying on the mind-body connection to light my way does not allow me to see far ahead, it usually leads me a short way in the direction. Thus, I usually feel more confident in performing workouts that I made up mere days or hours earlier than in performing workouts from a schedule I wrote many weeks before. This confidence is based on trust in my experience and my knowledge of the sport. There is no substitute for such experience and knowledge, which only time (and attention) can supply, but there are a few basic principles of training execution that can help you choose appropriate workouts on the fly. The first is the principle of progression. The goal of the training process is to become fitter. To become fitter you must train harder. To avoid injury and overtraining in your efforts to become fitter, you must train incrementally harder. Your workload should increase slowly and steadily throughout the training cycle. Next week’s training load should be a bit greater than this week’s, and so forth. You can also work backward. The workouts you do in the week preceding your peak training week should be slightly less challenging, and so forth. The second guiding principle of effective training execution is specificity. Your training should become increasingly specific to the demands of your most important race. For example, if your peak race is a marathon, your long runs should move closer and closer to marathon distance and you should do more and more running in the range of your goal marathon pace, while de-emphasizing less marathon-specific types of training (e.g., speed intervals) as race day draws nearer.