U.S. Soccer doubled down on its contention that the wage discrimination lawsuit filed last year by USWNT members lacks merit because it says players on the women's and men's national teams do not perform equal work, according to court filings Monday night.

Lawyers for both the players and the federation faced a deadline to file responses to earlier motions for summary judgment, motions that essentially asked Judge R. Gary Klausner to rule in their respective side's favor without a jury trial based on facts already presented.

The trial is scheduled to begin May 5 in federal court in California, with players seeking at least $66 million in damages.

The motion filed on behalf of U.S. Soccer on Monday reiterated a number of objections made throughout the lawsuit. But among the most stark were repeated assertions that, regardless of any other consideration, players from the two teams do not perform equal work -- either in terms of revenue potential or the actual physical labor required.

As a result, U.S. Soccer said, women's players do not qualify for relief under the Equal Pay Act or Title VII of the 1964 Civil Rights Act.

"The overall soccer-playing ability required to compete at the senior men's national team level is materially influenced by the level of certain physical attributes," the defense motion stated at one point, "Such as speed and strength, required for the job."

That followed the original motion for summary judgment, in which U.S. Soccer stated that women's players did not perform jobs requiring "equal skill, effort and responsibility under similar working conditions."

Referencing the players' earlier contention that "WNT players and MNT players expend equal amounts of effort performing on their respective national teams," U.S. Soccer said the statement could not be considered undisputed fact for the purpose of deciding on summary judgment.

"It is not sufficient to render it undisputed that the jobs of WNT player and MNT player require equal effort," one defense filing stated.

U.S. Soccer went on to allege that beyond physical differences, women's and men's players did not perform equal work because, in effect, women's soccer is easier than men's soccer.

"There is also evidence that MNT players face tougher competition, even on a relative basis," the defense motion stated. "There is a significantly deeper pool of competition in men's international soccer than there is in women's international soccer, even when assessing the issue in relative terms."

The federation went on to say that the men's team played in more difficult environments, such as those found in World Cup qualifiers in Mexico and Central America.

"This ridiculous 'argument' belongs in the Paleolithic Era," said Molly Levison, a spokesperson for the players. "It sounds as if it has been made by a caveman. Literally everyone in the world understands that an argument that male players 'have more responsibility' is just plain, simple sexism and illustrates the very gender discrimination that caused us to file this lawsuit to begin with. So [I'm] looking forward to trial on May 5."

U.S. Soccer noted that the World Cup is the only tournament the women's team competes in that generates prize money (there is no prize money for the Olympics), while the men's team competes in revenue-generating events such as the Gold Cup and Copa America.

The federation also presented viewership statistics it said proved more people watched the men's team, thereby placing greater responsibility on the shoulders of those players. The federation said the men's team earned better television ratings in its last Men's World Cup appearance than the women did in the 2019 Women's World Cup. It did not note in that section of the motion that the men's team failed to qualify for the 2018 World Cup or that the 2014 World Cup it referenced was played in time zones in Brazil more in sync with U.S. markets.

In their response Monday to U.S. Soccer's original motion for summary judgment, lawyers for the players involved in the suit again noted U.S. Soccer president Carlos Cordeiro's statement while running for his current position that "female players have not been treated equally."

The plaintiffs pointed to the example of male and female firefighters, jobs that require "the same skill and effort and responsibilities." If that is the case, unequal pay would not be allowed just because male firefighters might be stronger than their female peers, on average.

"That biological distinction is not a justification for discrimination," the plaintiffs said. "It is the prohibited discrimination itself."

With less than two months remaining until the scheduled trial date, the filings left the impression of the federation digging in and the two sides being far apart on fundamental philosophical questions, let alone smaller-scale financial details.

"The job skills and effort and responsibilities are the same," lawyers for the plaintiffs said. "It is all equal work requiring equal pay under the [Equal Pay Act]. Arguing that the WNT did not win its two World Cups 'against the most elite male soccer players in the world' is not a defense under the EPA; it is a tone deaf admission of blatant gender-based discrimination."