[barry-cotter]

Neither of your examples qualify as deliberate practice. People can plateau at one skill level for decades and make sudden jumps in ability by deliberately focusing on one specific skill. Expertise is at least in part, the combination of excellence in multiple related skills.

> An expert breaks down the skills that are required to be expert and focuses on improving those skill chunks during practice or day-to-day activities, often paired with immediate coaching feedback. Another important feature of deliberate practice lies in continually practicing a skill at more challenging levels with the intention of mastering it.

K. Anders Ericsson, Ralf Th. Krampe, and Clemens Tesch-Romer. The Role of Deliberate Practice in the Acquisition of Expert Performance. Psychological Review 1993, Vol. 100. No. 3, 363-406 [

[taneq]

That's kind of the point. "Deliberate practice" definitely helps to hone particular skills which fill holes in your overall competence. When you're performing at ultra high levels, you probably already have optimal performance in most areas, and all you have left to practice are particular skills.

Also, how you measure "sports performance" and what a percentage point means at different levels seems crucial to the whole thing. Maybe deliberate practice only accounts for 1% of performance... but an athlete who's 99% perfect is twice as good as an athlete who's 98% perfect.