Yoga is a group of physical, mental, and spiritual practices or disciplines which originated in ancient India. Yoga is one of the six orthodox philosophical schools of Hinduism.
Pilates is a physical fitness system developed in the early 20th century by Joseph Pilates, after whom it was named. Pilates called his method "Contrology".
HIIT focuses on large, global muscles and Pilates works on the core, so when combined they work on both large and small muscle groups. This ensures a whole body focus.