On its surface, Augiethe story of a fitness giant who contracted ALS (Amyotrophic lateral sclerosis, aka Lou Gehrig’s disease), might be a downer of a documentary to watch. That would be wrong. Instead, Augie turns out to be a love story like no other and an unforgettable journey that gives us all hope. In many ways it shares some of the same attributes as the Oscar-nominated Alzheimer’s docu Glen Campbell: I’ll Be Me, which detailed the singer’s valiant fight against a debilitating and cruel disease, while still showing a strong will to perform and survive. It isn’t a coincidence that both films come from director James Keach.

This one is the story of Augustine Nieto, the man behind the fitness world’s Lifecycle, a machine that became a staple in gyms everywhere and turned Nieto into a huge success in the business world. Fate intervened, however, and 13 years ago he was diagnosed with ALS and the devastating news that he probably wouldn’t have much longer to live. The film pulls no punches in showing how this affected him initially — even leading to a path toward suicide — before he found his true calling and began using his own business acumen to create a foundation and try to find a cure with the same determination he had when taking the exercise industry by storm. It changed everything even as he lost the ability to communicate in ways we all take for granted.

At this point Augie can only “talk” with his big toe as he types out words that way. But as I say in my video review above. this movie is anything but depressing to watch — much of that because Keach focuses on humor in surprising ways. In fact, the movie opens with Augie, sitting in his elaborate wheelchair, telling a joke. You immediately warm to him, and thankfully, as off-color as those jokes are, Augie keeps them coming. He even promises to put people on his email “porn list” if they ask.

The other thing that makes this film work is the love story it tells between Augie and his wife Lynne, who is just as key here as the title subject himself. She is an indomitable spirit who refers to their fate as “our diagnosis” or “our fight,” and her place in his life and in the film about it cannot be underestimated. The two old friends rediscovered each other later in life after each married someone else. She is such a warm presence here you can see she is a big reason Augie has defied all predictions about his mortality — in fact, he just celebrated his 60th birthday, and it’s clear he and Lynne are going to keep on until they do find a cure. Keach has done a fine job incorporating his two main subjects into the structure of the movie, deftly using interviews with friends and family plus new footage and archival film that is often weaved in and out by seeing Augie watch it on the laptop on his chair. It’s an effective device in a must-see movie you won’t soon forget.

Keach and Eric Carlson are producers. The film opes theatrically today in Los Angeles at Laemmle’s Music Hall and in New York City at Cinema Village. It hits iTunes for digital download Tuesday. Check it out wherever you can.

Do you plan on seeing Augie? Let us know what you think.