The NASM CPT7 Study Guide identifies marching as a suitable core progression from a static plank. Once a client can hold a plank with proper form, progression involves adding dynamic movements that challenge stability further. Marching requires alternately lifting each foot off the ground while maintaining plank alignment, which increases core engagement by adding an anti-rotational component and shifting the center of gravity. This type of progression maintains the isometric trunk stability goal while increasing neuromuscular demand .