Under investigation for child abuse allegations, Son Woong-jung, football coach and father of South Korean Premier League star Son Heung-min, was seen kicking a young player at his namesake academy in a video obtained by Yonhap News Agency on Friday.

Another clip showed other coaches at Son Football Academy, located in the eastern city of Chuncheon, yell at junior players with profanity during a match in Fukuoka, Japan.

The senior Son and two of his coaches at the academy, including Son Heung-min's older brother, Heung-yun, are being investigated for charges that they have physically and verbally abused a player. The player's parents filed a complaint with police in March, and police then sent the case to prosecutors in April.

Son and the coaches were summoned for questioning for the first time Tuesday.

In one video clip, Son Woong-jung kicked a player during a match while the player was getting back on his feet and adjusting his socks after the ball had gone out of play.

After the academy's team conceded a goal, someone hurled profanity at players. One coach was heard as saying, "You guys can't talk, can't run, can't cut, can't defend and can't attack. And you can't even play for 30 minutes in this weather," while mixing in explicit language.

In another video, showing a match between a team from the academy and a Japanese squad in Fukuoka, one coach yelled at a player who misfired a shot. Multiple coaches were heard calling different players names.

The player whose parents filed the complaint against Son and his coaches did not play in this match but traveled with the team to Japan.

The academy said Son Woong-jung acknowledges some of the strong language that he had used, but it otherwise defended its coaches.

"Coach Son and his assistants were quite frustrated, because players couldn't execute things they had trained for several years. This was their first 11-on-11 match and since they were too nervous, they weren't able to do things that the coaching staff had emphasized every day."

As for offensive language used by its coaches, the academy said, "Coaches were trying to convey their messages quickly in a high-pressure situation and their expressions were not filtered. Such aggressive language came as coaches tried to instruct players. These words were absolutely not intended to emotionally abuse specific players."

When allegations against him and his staff surfaced last week, Son issued a statement to deny all the charges. He had said at the time he would try to adopt a new coaching style that better fits the changing times and that he would fully cooperate with the authorities in their ongoing investigation.

Parents of other players at the academy have dismissed abuse allegations against Son and his coaches, saying they have never once heard of or seen any corporal punishment at the football facility.