From Nookipedia, the Animal Crossing wiki
Jock villagers are male villagers in the Animal Crossing series. The name comes from the American stereotype, usually seen as high school or college jocks. A jock is a male athlete, in the light of the media, considered unintelligent and dull-witted, which is reflected in the Animal Crossing personality type by their key interests in physical fitness and sports, including wrestling and typical gym exercises such as leg-squats and push-ups. These interests are unseen in the game, unlike the other hobbies. Jocks are often immature and naive and are considered the male equivalent to peppy villagers.
Jocks are obsessed with sports, talking frequently about their love of sports and sporting progress. Stereotypically, they are also unintelligent, incessantly confusing themselves - calling the brain "the Brian" and failing to even grasp the concept of the game 'rock, paper, scissors'.
They are the brother-like characters in the game, giving pep talks to the player and appearing competitive toward them and other villagers when they partake in town events. They usually go to sleep at 12:00 AM and wake up at 6:30 AM. In New Leaf, they wake up at 7:00 AM. They are rarely angry unless offended by lazy villagers, who have conflicting personalities, but usually a discussion between the two will leave the jock villager confused and unable to talk. When jocks get sad, they say something like "I'm just sweating through my eyes!". When at the player's house, the villager will often say something like, "We have the same taste in sportswear!" They do not worry so much about fashion.
Below are some (not all) quotes made by jock villagers.