Fitness equipment company Tonal announced a $45 million round of funding that includes investment from Serena Williams' Serena Ventures. The latest round of funding was led by L Catterton, a private-equity firm that has also invested in Peloton, ThirdLove, ClassPass and The Honest Company. Tonal is a home fitness system that incorporates personalized video into a series of workout routines. It's one of the tech-driven fitness options having an impact on the health-and-wellness sector.