From Google AI:
Cross country is widely considered one of the hardest high school sports due to its demanding physical and mental requirements.
Athletes must possess exceptional stamina for long distances and face constant mental challenges, including pushing their physical limits and maintaining focus for the entire duration of a race without breaks.
Physical demands
Endurance: Cross country requires athletes to run for longer distances (typically three miles or more) compared to track runners, who may have shorter events.
High-impact and strain: The sport can be high-impact, as runners navigate various terrain, which adds strain to the body.
No "brakes": There are no time-outs or stoppages, and athletes must run hard from start to finish.
Mental demands
Perseverance: The sport requires immense mental toughness and perseverance to keep pushing through the physical pain and exhaustion.
Individual effort: While it is a team sport, it is also highly individual, and runners must find the motivation to compete against themselves and their personal limits.
Discipline: The rigorous training and practice needed to succeed demand a high level of discipline and commitment, which can make it less enjoyable and more challenging for some.