Richard Simmons was the hottest thing in exercise programs back in 1996. The garb may have changed, but fads are still fickle. Evan Hurd/Sygma/Corbis hide caption itoggle caption Evan Hurd/Sygma/Corbis Shots - Health News How Will You Work Out When CrossFit Is No Longer Hip? January 2, 2015 Fitness programs typically don't have much staying power. People are already saying adios to Zumba and Pilates. The cheapest and simplest routines are more likely to be keepers. Think down dog.