Ever since it was considered “safe” for women to work out in the 1950s (before then, doctors thought that exercise could damage a woman’s reproductive organs), absurd workout fads have come and gone. From belts to the first exercise machinery, here are the weirdest workout fads in world history:

1. Mechanotherapy: Although exercise equipment is found in all gyms nowadays, the idea of using large equipment to enhance one’s workout was new and peculiar in the late 1800s. Gustav Zander invented Mechanotherapy, which required the use of a series of strangely shaped machines that targeted particular muscles. Zander’s equipment was popular among private facilities and spas throughout the United States, but the fad died down by the early 1920s.

2. Vibrating Belts: People are always trying to find new, creative ways to work out without actually expending any effort. Popular during the 1960s, this “workout” involved wrapping an elastic band around a body part and then using a motor to vibrate the band. Supporters of the belt believed that the vibrations increased muscle tone and broke down fat.

3. Exercise Wheels: Otto Feick created this device in 1925. It reached the peak of its popularity when the wheel was showcased at the 1936 Berlin Olympics. The machine was and still is used by gymnasts to stretch their bodies and perform circus-like tricks.

4. Relax-a-Cizor: People never gave up hope that they could work out without lifting a finger. Introduced in the 1940s, the Relax-a-Cizor quickly spiked in popularity with over 40,000 sold. The company claimed that by placing damp cloth pads, connected to wires, on the body, muscles would contract as a result of the current running through the wires. Eventually, however, the government was forced to shut down the company after several lawsuits were filed.

5. 8 Minute Abs: During the 1980s, when home workout videos became popular, the 8 Minute Ab workout video saw huge success with millions of copies sold. The tape promised toned abs in only 8 minutes’ time.

6. Wondercycle Exercisulator: This is basically an old version of the currently popular stationary bike. Popular Mechanics describes the machine as a “contraption that linked a set of pedals to a saddle-like seat that moved in unison with them, kind of like riding a horse.” Its advertisement featured a saddle-like cord that was hooked around a man’s head.

7. Abdomenizer: While the 1980s saw countless fitness fads, the Abdomenizer proved to be among the most popular, especially among women. The device was simply a curved piece of plastic with handles on which people rocked back and forth while doing sit-ups. Over one million sold!