It would never have occurred to me that having rhythm was a prerequisite to being a good paramedic.

But the people who run the Chicago Fire Department must have thought so.

For two years, the Fire Department administered something called the Step Test as a graduation requirement for paramedic candidates at the Training Academy.

The Step Test required trainees to continuously step up and down onto an 18-inch-high box for not less than two minutes while holding a pair of 25-pound weights.

And here’s the fun part, they had to keep the beat while stepping — up, up, down, down — with alternating feet at 112 beats per second. Lose the beat and that six weeks of training went down the tubes.

So maybe you’re like me and thinking, what did they do: put “Fire” by The Ohio Players on the boombox before they get started?

No, of course not, because I’m probably the only person old enough to even remember that song.

They just used a metronome. There wasn’t even extra credit for those who can squeeze a cha-cha-cha into the step sequence.

Marni Willenson isn’t sure whether the Step Test would be a good means of evaluating a dancer or an aerobics instructor. But she’s completely convinced it has nothing to do with whether or not somebody would make a good paramedic.

“It is absurd,” said Willenson, who filed suit Friday in U.S. District Court on behalf of 12 women who say the Fire Department used the Step Test and another flawed physical performance test as the latest maneuvers in a long-running effort to intentionally exclude women.

A federal appeals court ruled in September that the Fire Department had used discriminatory physical performance tests for more than a decade to prevent paramedic applicants from just getting into the training academy.

Lawyers Willenson and Joshua Karsh say that instead of using physical tests to keep women out of the academy, the Fire Department has started allowing more women to enter the academy — and now uses physical tests to flunk them before they can graduate.

Late Monday, the city released a statement saying it could not comment on the lawsuit, but said “the Fire Department does not condone discrimination of any kind, and no longer uses the physical abilities tests that are included in this suit.”

According to the lawsuit, the city administered two new physical tests to 179 men and 56 women trainees during 2014 and 2015. One hundred percent of the men passed, compared to only 79 percent of the women, the suit contends.

Obviously, this shows the department wasn’t really testing for rhythm, otherwise we can all agree more men would have flunked.

Rather, they were screening out women whose size and stature might make the weights and 18-inch step more challenging.

It’s a level of physical ability that the former women trainees don’t believe is a realistic measure of their qualifications to perform the work of a paramedic.

The suit contends this sort of testing has allowed Chicago’s paramedic ranks to remain more than 70 percent male, same as it was in 1996.

“It seemed like they wanted supermen,” said Donna Ruch, 50, who has worked on and off as a paramedic and firefighter in the western suburbs since 1989. Ruch was injured performing another test that the lawyers contend is unrealistic — carrying a 250-pound mannequin up and down six flights of stairs — and never completed her training.

I spoke to four of the plaintiffs, each of whom has previous experience as a paramedic either for suburban fire departments or private ambulance services.

All agreed that paramedics must be physically fit to deal with the rigors of a demanding job. But they said they have always been able to perform the work, which does not involve extreme step dancing.

I asked Jennifer Livingston, 39, who has worked as a paramedic since 2002, if she has rhythm.

“I have decent rhythm,” Livingston, of Logan Square, responded warily, not sure where I was headed.

“Being a paramedic is about treating people and helping them,” Livingston said.

It’s not about keeping rhythm to a 112-count beat on an 18-inch step.