The Philadelphia Union fired coach Peter Nowak in 2012 after getting complaints he hazed rookie players by spanking them so hard it hurt his hand, directed them to run 10 miles in warm weather without water, and was dismissive of concussion injuries, according to newly filed court documents.

Lawyers for the team and Nowak made filings recently as Nowak tries to convince a federal court to overturn an April 2015 arbitrator's ruling that upheld the dismissal and ordered Nowak to pay the team about $400,000 in legal fees and costs.

"The hazing of rookies, by spanking them, sometimes with a sandal, was completely unacceptable," wrote arbitrator Margaret Brogan in April.

"His description of what he did was quite unnerving, especially when he described how he put his hand in a bucket of ice water to ease his pain, obviously because he was hitting the young people so hard," said Brogan, who also regularly arbitrates Major League Baseball player salaries.

Brogan also found that he required injured players to run 10 miles in 80 degree heat, taking water bottles away to toughen them up.

"Nowak created an environment where players felt the need to hide or mask concussions," the team's lawyers wrote. "Indeed, the record evidence established that Nowak vilified players who suffered from concussion symptoms."

Nowak sued the team in July 2012, a month after he was fired, despite a contract that was to pay him through 2015. At that time, the team's record was 2-7-2.

Nowak's lawyer said in a memorandum filed this week that the reasons for his dismissal were a pretext, the arbitrator was biased against him and her ruling should be overturned.

Last year, his lawyer argued the firing was unfair because the team did not get Nowak's input, he did not have a written record of discipline, he wasn't given a chance to "cure" the issues involved and it was not done in good faith, as his contract required.

Calls seeking comment from lawyers for Nowak and the team were not immediately returned Wednesday.