FitnessGram is a school fitness assessment program used in the United States, and its Progressive Aerobic Cardiovascular Endurance Run, or PACER, became its most recognisable part. Students run 20-meter laps back and forth in time to recorded beeps that gradually speed up. The recorded introduction spread far beyond gyms after students who grew up with the test began posting about it online, turning the announcement into shared nostalgia. Its length, formal delivery and instant association with forced running have kept it popular for memes about effort, endurance and impending exhaustion.