Today, athletes use more structured interval training workouts and HIT (High-Intensity Training) to build speed and endurance. 1  This variation of interval training and speed work can be a simple or sophisticated routine, but the basics are still the same as the original fartlek training.
Annabella Avery Bella Thorne (born October 8, 1997) is an American actress and singer.
Bella Thorne and Gregg Sulkin LOS ANGELES, CA - AUGUST 16: Actors Bella Thorne (L) and Gregg Sulkin pose in the press room during the Teen Choice Awards 2015 at the USC Galen Center on August 16, 2015 in Los Angeles, California.