This video shows burpee form more simply and clearly than any other I’ve seen. If you’re trying to learn how to do them, I think this video shows it best.
I prefer doing them barefoot and bring my knees outside my elbows when I jump forward, but those are matters of taste. Note that he touches his chest and chin at the same time and keeps his back rigid, not curling it. Easy ways to challenge yourself with the same form are to jump higher and bring your hands closer to each other for the pushup, which works the same muscles but harder.
Good luck with your burpees!
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On initiative, leadership, the environment, and burpees