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Regression to Medium Speed

Another study finds that athletes struggle to keep hard days hard and easy days easy.

This is an interesting graph that's worth thinking about:

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It's from a study of Dutch soccer players, just published in the International Journal of Sports Physiology and Performance; researchers at the University of Groningen followed them for an entire season, recording (among other things) how hard the coaches intended each training session to be (white bars), and how hard the players perceived each session to be (black bars). The key finding is that the players perceived easy sessions to be significantly harder than intended, and hard sessions to be significantly easier than intended. This mirrors the findings from a 2001 study of runners by Carl Foster and his colleagues.

There may be many factors contributing to this mismatch between intended and experienced intensity. But in the end, what matters is the outcome. There's been plenty of talk recently about the idea of "polarized training" (a newish name for a very old concept), whose basic principle is: Keep the hard days hard, and the easy days easy. That's a nice idea, but it's undermined by the fairly universal tendency to drift toward the middle -- something worth bearing in mind for both coaches and athletes.


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