All coaches yell.
They scream at a lack of effort, erupt over an egregious mistake, sometimes it's a calculated outburst (the late Montreal Canadiens coach Pat Burns was a master of contrived rage) but more often it isn't.
Some are far more shouty than others, of course, and the better ones understand there is a point at which the short, sharp, shock morphs into verbal and psychological abuse.
Still others prefer the sotto voce approach, but if you're in a big-time coaching gig, you'll end up yelling at some point.
Which brings us to the thorny case of Chun Jae Su, the head coach of the U.S. short-track speed-skating team.
Chun is a blunt, old-school sort who rose through the demanding – and wildly successful – South Korean skating program and had a brief stop in Canada before catching on with United States.
Now he faces a litany of accusations of physical and emotional abuse from his charges – the most sensational: masterminding a sabotage operation against a Canadian skater he once coached – because of his methods.
Chun, who has been placed on administrative leave, has flatly denied doing anything wrong, and a group of athletes from the team have publicly rallied to his side.
It seems that one person's abusive tirade is another's motivational technique.
But does anger actually work?
Some sports psychologists say a bracing blast of blue language can focus attention and create "emotional contagion," infusing energy and intensity into a team or an individual athlete.
Withering language, however, has limited effectiveness – negativity is also contagious.
Kim Dorsch, a kinesiology professor at the University of Regina who has researched the effects of abusive coaching on children, said "fear works, but only for so long ... it leads to an increase in arousal level, which then inhibits performance. You can't perform at your best if you're anxious."
And according to a complaint filed with a U.S. arbitrator, Chun has created an environment where the athletes are "fearful and anxious."
It has also, apparently, led to a situation in which a skater can be prodded into an act of sabotage against a competitor – a rare act in amateur sports, although some triathletes have apparently been known to tamper with other racers' gear in transition areas.
That skater, 21-year-old Simon Cho, is not among the claimants in the case, his alleged confession is contained in the documents filed before the arbitrator (they also record thinly-veiled threats against anyone who didn't keep the affair hush-hush.)
Not the best context, then, for the U.S. team to be holding its World Cup trials next week – more than half the team has been boycotting Chun's training sessions since June.
Ed Williams, a lawyer for the 14 athletes who signed a code of conduct complaint against Chun – the list includes two-time Olympic medalist J.R. Celski and Canadian-born Olympian Travis Jayner – described the situation "very, very distracting, as you can imagine."
According to U.S. federal law, disputes involving amateur athletes are settled by an arbitrator, in this case the parties are slated to appear at a hearing that begins on Oct. 3 in Salt Lake City, where the national program is based.
Both Chun and his accusers will have a chance to testify ("under oath, and penalty of perjury," Williams pointed out tartly).
The claimants have asked that Chun and his assistants be banned from coaching the team and from travelling with them during the World Cup season.
That's one solution, but what if the effects of Chun's methods linger?
Dorsch said there's a tendency in elite sport, in which coaches are under particular pressure to develop winners, for behaviour to migrate from coaches to athletes, because "if it's good for me, it's good for the others."
"It becomes legitimized, there's a perception of 'I should be able to handle this,'" said Dorsch, adding the literature suggests athletes can be affected even when they're not the brunt of the abuse.
Six-time Canadian Olympian Clara Hughes, a former long-track speed skater and cyclist who is deeply involved with children's charity Right to Play, said unethical coaching practices can leave deep impressions.
"I think especially with young athletes, that could be the potential danger is if they fall into the wrong hands," she said.
Most of Chun's athletes are no longer kids, but the allegations – which are also the subject of an internal investigation by U.S. Speedskating – don't make for pleasant reading.
According to the documents, on one occasion Chun grabbed one skater by the neck and shoved him up against a wall and "repeatedly hit him."
On another, he emptied a bottle of water on an athlete's head and refused to speak to him for several days.
He's also accused of using demeaning language, calling athletes "worthless," or "disgusting." In one case he allegedly called a female skater a "fat cow."
More seriously, Chun is accused of forcing athletes to train to the point of injuring themselves, and imposing "punishment training."
He also allegedly told injured competitors to start skating before they were medically cleared, and reportedly forced an athlete to stay out on the ice despite feeling sick to his stomach.
The athlete ended up defecating in his racing suit.
With a report from Hayley Mick