Undergraduate / Comm App Short Activity Essay- "Endure the Storm" [5]

This is a rough draft. I am wondering if the essay flows well and I'm not sure about the last sentence. Does it focus enough on myself? Any comments or critiques would be greatly appreciated.

Prompt: Please elaborate on one of your activities (extracurricular, personal activities, or work experience)(150 words or fewer).

"If you wish to see the rainbow you must first endure the storm"; While I may not be able to link this quote to its original orator, I suspect that individual was a cross country runner. In no other sport do competitors willfully subject themselves to the fatigue, anxiety, and pain associated with a three-mile race. The whirlwind of this distant storm is initially felt during blazing summer practices and slowly evolves into a blitzkrieg sweat and oxygen indebted lungs by the first race. The rainbow is representative of the unrivaled feelings of personal pride and accomplishment invoked by crossing the finish line. Although the idea of work and reward is exemplified through my sport, it is a universal message. Excellent grades are not a product of single bursts of enthusiasm and moral fiber isn't strengthened by periodic acts of benevolence. Many endeavors prove neither easy nor provide instant gratification, but through tenacity I strive to obtain greater rewards.

R Clark