When she was young, the 21-time Grand Slam champion had doubts about her own physique.
See video of this youngster get pumped up for playoff run.
The Two-Minute Torcher
The Crazy Move That Torches Your Gut
The Two-For-One Abs Exercise: Running Man
Swedish researchers published a report which ties strength in adolescents to a decreased risk of death.
The 90-Second Ab Blaster
Work your entire core from shoulders to hips.