Like so many dubious health claims, stretching before exercise has its roots in yoga culture. Maria Konnikova explains that stretching is exercise in-and-of itself and shouldn't be treated like a warm-up. Then why do so many trainers and health nuts preach stretching as gospel? Konnikova is a regular guest on The Gist, a New Yorker staff writer, and the author of The Confidence Game.

In the Spiel, Rachel Maddow's report on President Donald Trump's taxes was fine news but bad showmanship.

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