Watch: Serena Williams' acrobatic pre-match warm-up

How does the No. 1 women's tennis player in the world warm-up before her matches? With a little music, a little dancing, and ... some handstand push-ups.

Serena Williams posted a video of her pre-match routine on Instagram, and I think it's safe to say there's no need to worry about her core strength.

"It's just really silly," Serena said after her 6-1, 6-3 win over Jelena Jankovic in the Western & Southern Open quarterfinals. "It's just Serena doing hand stands. Yeah, that's it. I guess I love hand stands."