While even a year makes a huge difference for a professional athlete in terms of development, greater progress can be made in four years.
Consider, for instance, the case of swimmer Takeshi Matsuda, who achieved a remarkable feat four years ago in the 2004 Athens Summer Olympics.
At age 20, Matsuda, called "the vinyl house hero" because he started out his swimming career at a hand-made greenhouse-like pool in Nobeoka, Miyazaki Prefecture — and kept practicing there even after leaving the town — participated in the 400-, 800-, and 1,500-meter freestyle races in Athens.