An effective training program demands constant trade-offs. Every component of training cannot receive equal emphases. If one component is emphasized then another must be de-emphasized. Good training is often compared to a mosaic but in my mind that is much too static, it is more like a kaleidoscope, ever changing in a state of dynamic equilibrium. It is so much more than balancing volume, intensity and density as it is often portrayed. It is actually careful consideration of the interaction of all training components while minding that all components of training should be trained at all times in different proportions. The trade-offs, the mix if you will, changes as the athlete accumulates training day to day, week to week to week, month to month and year to year and must be adjusted accordingly to insure continued adaptation. Carefully consider the trade-offs. Weigh the cost benefit analysis relative to each trade off and relative to the short and long term goals of the training program. There is a firm foundation for all this in scientific training principles but ultimately it requires a heavy dose of coach?s intuition and knowledge of the athlete. No formula or algorithm, just constant adjustment and fine tuning.