premise: A young athlete is on the field looking at something in the distance. hypothesis: An athlete looking in the distance.
entailment: A young athlete is still an athlete, thus having more details allows two different variations in details with these two sentences.  "An athlete looking in the distance" is an observation statement allowing mystery and doesnt much detail where as "A young athlete is on the field looking at something in the distance" is much more explicit in details with the words " young" which is an adjective, "on the field" which is the location detail,  and adding "something" allows the reader to gain awareness that he isn't just standing there thinking.