According to Wikipedia.org, the Plank (also called front hold, hover, or abdominal bridge) is an isometric core strength exercise that involves maintaining a position similar to a push up for the maximum possible time.
The Guiness World Records lists the record for longest duration of a front plank, resting on elbows, as 8 hours, 15 minutes and 15 seconds, set by veteran Marine officer George Hood on February 20, 2020.