How is climbing different from other sports?

Debate/Jens: Why do very few of the best rock climbers follow a strict training programme? Would they actually improve if they would periodize their training as other athletes? As climbing is mentally unique, See below, it might be as good with or without periodization? 1. Climbers "try to perform" continuously several times a day, the key is inspiration. Other athletes competes seldom, but train in a structured way for a given date, time and place. 2. Climbing is unique as we often stand still and rest which creates thinking/anxiety. A normal answer for other sportsmen are, "as soon as the game started my anxiety disappeared". 3. Fear of heights and falling is often involved in climbing.