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.
To see all of the birthday girl's best looks, check out the gallery below! PHOTOS: All of Bella Thorne's best red carpet moments. TAGS/ Bella Thorne , Birthdays , Fashion , Style , Top Stories , Gregg Sulkin.