Fact: Treadmills were once used as a form of prison punishment.

Stop the torture at City Surf Fitness.

The Uptown facility houses ten stationary surfboards built for bitchin’ muscle toning (you may have spotted the Surfset Fitness contraptions on an episode of Shark Tank).

Sympathizing with landlocked Bettys, four young Dallas entrepreneurs introduced a surf-inspired workout and designed four classes around balance, yoga, aerobics, and Pilates.

Hang ten in 864 square feet of studio, while upbeat, new-wave tunes (chill out to Jack Johnson during the Buddha Board session) and cinematic surf footage screened on a huge back wall induce a little paradise.

Socks and shoes are banned, but gym clothes are required.

So keep the bikini on lockdown.

City Surf Fitness, 2805 Allen Street, suite 113 (214-880-7433 citysurffitness.com), classes are $10 and up.

Photo: Courtesy of City Surf Fitness