Most of the cast met in, or studied at Michael Jacques film study class in Fort Lauderdale.
Erick and John came up with "Gym Shorts" while working out together at LA Fitness.
The character of "Sam" was created originally as a marketing tool to get an instant fan base. Originally just named "Front Desk Guy", Producers targeted local influencers and local celebrities to be cast as the revolving door of characters. Just like at most gyms, the front desk person is constantly changing. Sam can be played by a female or male but is played by a different influencer every episode and always has their signature lollipop and catchphrase "Welcome to Uranus"
Wil Jackson, who plays Wesley, was originally thought of for "Digits Guy", a feature role in the short sketch the series was based on. As the series developed the very talented actor was upgraded to a more fitting lead character role in the series.
The creators thought of changing the name from Gym Shorts to "Rivals" since at some point most characters, including the actual Gym, will have a rival they have to confront.