This edition of the Guidelines employs the Frequency (how
often), Intensity (how hard), Time (duration or how long), and
Type (mode or what kind), with the addition of total Volume
(amount) and Progression (advancement) or the FITT-VP
principle of Ex Rx to be consistent with the American College of
Sports Medicine (ACSM) recommendations made in its
companion evidence-based position stand (20).
https://www.acsm.org/education-resources/trending-topics-resources/physical-activity-guidelines