Looking at pictures of your deceased parent's brain must not be easy.

But that's exactly what Rebecca Carpenter had to do while making Requiem for a Running Back, her deeply moving documentary about her late father, Lew Carpenter. Lew had played professional football, mostly for the Green Bay Packers, from 1953-1963, retiring at age 33 and then spending more than three decades coaching in the NFL. When he died in 2010, his family was contacted by researchers at Boston University who requested that they be allowed to study his brain.

The results showed that Lew suffered from chronic traumatic encephalopathy (CTE) as a result of the violent physical contact he endured while playing the sport. The diagnosis wasn't surprising, considering that he had suffered from severe mood swings, depression and significant mental deterioration in the last years of his life. This documentary stems from his daughter's attempts to better understand both her father and the sport that enabled to rise from poverty but ultimately destroyed his quality of life.

There have been other documentaries about the subject, as well as the 2015 drama Concussion, starring Will Smith as Bennet Omalu, the pioneering doctor who raised awareness of CTE (Omalu is among this film's interview subjects). But none are as personal as this effort, which includes a scene of the filmmaker bursting into tears while being shown pictures of her father's damaged brain. "Maybe that's too much information," the concerned neuropathologist comments after providing harrowing details about her dad's condition.

Carpenter discovered that her father hadn't suffered any known concussions during his career, which are normally a primary cause of CTE. Rather, the theory is that he suffered from "brain slosh," which is what happens when the brain is hurled against the skull as a result of a sudden jolt or collision. The doc includes interviews with various experts on the subject, as well as computer graphics dramatically illustrating the effect.

Among the other interview subjects are players who knew or worked with Carpenter's father, including such well-known player-authors as Jerry Kramer and Dave Meggysey. But it's the segment featuring former Pittsburgh Steeler tight end John Hilton that proves the most painful to watch. The then-69-year-old Hilton, who has since passed away, can barely form a coherent thought as he vainly tries to answer a simple question.[

Requiem for a Running Back explores various aspects of the game, including how it became more violent over the years and the devastating effect of artificial turf. One player bitterly explains that the owners' attitude toward players thought to be suffering from CTE is "delay, deny, hope they die." The wife of a player who suffered from the condition likens her final years with him to "living with a rattlesnake."

Seen in a clip from a televised interview, former player and coach Mike Ditka (Mike Ditka!) says that knowing what he knows now, he wouldn't let his son play football. "I think the risk is worse than the reward!" he says sorrowfully.

That pretty much says it all.

Production company: You Gotta Love
Distributor: Hydro Studios
Director: Rebecca Carpenter
Producer: Sara Dee
Executive producer: Max Mayer
Director of photography: Eric Wycoff
Editors: Elisa Bonora, Parker Laramie, Troy Takaki
Composer: Brian H. Kim

90 minutes