Great, fitness-focused domain name that blends in the words "gym" and "fantastic".
Gymtastic has nine letters and three syllables. Three syllable names are used by established brands like Grammarly, Microsoft and Toshiba.
Gymtastic.com is a .com domain. Dot com domains are the most prestigious top-level-domain in the world, famously used by websites like youtube.com. A .com is the first thing people think of when they think of a website.