A striking and headline-making fraud case resulted in a conviction last Friday, when Charlie Javice was found guilty in federal court of conning JPMorgan Chase out of $175 million. The bank has also sued Ms. Javice, a 32-year-old entrepreneur who once made the Forbes 30 Under 30 list, for elaborately falsifying her student-finance start-up’s customer list.

But in a Manhattan courthouse hearing this week, the deliberations about Ms. Javice’s bail terms turned into an absurdist episode, as her legal team argued that an order for her to wear an ankle monitor would hinder her ability to teach Pilates.

Her lawyer, Ronald Sullivan, who did not immediately respond to a request for comment on the proceedings, stood at a podium and waved his arms to demonstrate the physicality needed to practice Pilates, which Ms. Javice teaches professionally in South Florida, sometimes leading three to four classes a day.

“To have your legs in the air and the monitor going up and down on your leg, it is a significant encumbrance,” Mr. Sullivan said, also noting that the monitor “would remove the possibility of the one thing she can now do, which is teach her classes.”

The hearing’s focus on the bulky surveillance device was another case of ankle monitors taking space within the news and pop culture sphere. Anna Delvey, the fake heiress convicted of theft and larceny, wore a bedazzled ankle monitor on “Dancing With the Stars” last year, and an ankle monitor appears regularly in the medical drama “The Pitt,” worn by a resident named Cassie McKay, who drilled through hers in a recent episode to halt its blaring alarm.

For Ms. Javice and her legal team, the issue centered on her inability to earn money while wearing the monitor, with little if any acknowledgment that other, less physically demanding jobs were an option. In a court filing, her lawyers argued that: “Ms. Javice specializes in fitness instruction that requires demanding physical movement and full flexibility and range of motion, specifically around her feet and ankles. Indeed, Ms. Javice’s supervisor reports that Ms. Javice’s services are sought after because her instruction is particularly challenging and dynamic.”

Wearing a Moncler coat, leggings and black flats, Ms. Javice sat quietly through the hearing.

Judge Alvin K. Hellerstein of Federal District Court in Manhattan, who has presided over high-profile cases such as the Harvey Weinstein trial and the tax fraud trial of the art dealer Mary Boone, took time to weigh in on the matter.

“It’s not heavy, it probably weighs a pound,” Judge Hellerstein said of the monitor. “So I don’t know,” he continued. “I accept what you say, that it’s a restriction on her ability to do the advanced Pilates that she does.” But, he noted, “I can’t say there is no risk of flight.”

About an hour of arguments on the matter ensued, featuring court exhibits depicting Ms. Javice teaching Pilates. At one point, she huddled with her lawyers away from the microphone and podium, demonstrating with her arms. And during his retreat to chambers, Judge Hellerstein brought with him printouts of photos of Ms. Javice exercising to help him mull things over.

Ms. Javice embraced her co-defendant, Olivier Amar, for several seconds before the hearing began and helped him adjust something on the lapel of his suit. Mr. Amar, who sat between his lawyers during the proceedings, was an executive at Ms. Javice’s student-finance start-up, Frank, and was also ordered to wear an ankle monitor. His lawyers contested that the device was unsightly and “makes him a pariah.”

In a court filing, the acting U.S. attorney in Manhattan, Matthew Podolsky, wrote that “the defendants’ current bail packages are not sufficient to address the risk of flight.” He added: “Nor do Javice’s arguments that an ankle monitor inhibits her ability to teach an exercise class in any way override the statutory detention provisions of the Bail Reform Act. Therefore, for the reasons set forth above, the Government respectfully requests that the Court modify the defendants’ bail conditions to require both defendants to resume GPS location monitoring.”

For the time being, Judge Hellerstein decided the monitor was required.

Ms. Javice, who now faces the possibility of decades in prison, is free on a $2 million bond ahead of her sentencing this summer. She was fitted with her ankle monitor before leaving the courthouse on Tuesday.

Kirsten Noyes contributed research.