Pushups with Side Plank

Get into pushup position on knees or toes. Do a pushup and,
as you come up, rotate to the right into a side plank (keep knee
down on the floor or balance with feet stacked for advanced),
taking left arm up to the ceiling. Come back into pushup position
and do another pushup followed by a side plank to the left side.
Continue alternating pushups and side planks for all reps,
modifying when needed.