Question: 20 ways to do planks?
Answer: Elbow plank. Lie facedown with legs extended and elbows bent and directly under shoulders; clasp your hands. ... 
Plank with opposite limb extension. ... 
Elbow plank with arm/leg lift. ... 
Elbow side plank. ... 
Standard side plank. ... 
Side plank with twist. ... 
Back plank. ... 
Straight-arm back plank with bent legs.