Brittany Johnson, wife of former NFL running back Chris Johnson, has shared a poignant video on social media illustrating the rapid progression of amyotrophic lateral sclerosis (ALS) since his diagnosis.

Chris Johnson, the 2009 NFL Offensive Player of the Year, revealed his ALS diagnosis in an interview with Michael Strahan on "Good Morning America" last week. He was diagnosed with the progressive neurological disease, which affects motor neurons, in the past year at the age of 39.

The video posted by Brittany contrasts a healthy Johnson consoling their daughter Honey after a track meet and preparing for Fourth of July festivities with their current state. "One year. That’s all the time between this video and where we are today," she wrote in the caption, emphasizing the stark change.

The footage also captures Johnson participating in a video with his daughter as she unboxes gifts, with Honey calling him "the best dad in the world." Brittany described the video as capturing "exactly who he is, the kind of dad who always shows up, always encourages, and always puts his kids first."

She expressed heartbreak at seeing how quickly ALS can impact daily life. "Looking back now, it’s heartbreaking to see how quickly ALS can take away so many of the things most of us never think twice about," she stated.

Johnson explained in his "Good Morning America" interview that he first noticed symptoms as weakness in his right hand, initially attributing it to a football-related injury. After extensive testing, he received the ALS diagnosis.

"It was hard hearing that but after watching Good Morning America and seeing Dr Merit [Cudkowicz] with Eric Dane, we reached out to her," Johnson said. "She was willing to think more creatively and offer experimental treatments that might help and advance research."

Johnson, known for his speed during his ten-year NFL career, played his last season in 2017. He is particularly remembered for his six seasons with the Tennessee Titans, where he earned three Pro Bowl selections and the Offensive Player of the Year award in 2009.

Johnson was one of the fastest running backs in NFL history, playing for the Titans and Jets

Brittany Johnson shared that she was initially in denial about the diagnosis, with her primary concern being their four children. "You want it to be anything else, you want the doctors to be wrong," she said. "The life that we previously had is now a thing of the past, but we're still hopeful that a breakthrough will happen, and that God, a miracle will happen."

Chris Johnson stated that his wife has been a constant support since his diagnosis, and that his children provide him with the motivation to continue. "It's continued to progress much faster than I imagined," he said. "I want people to understand just how quickly ALS can attack your body. Just over a year ago I was picking up my seven-year-old daughter so she could make a wish with her birthday cake. Today, I couldn't do that."

Brittany Johnson concluded her post by thanking those who participated in the Ice Bucket Challenge to raise funds for ALS research. ESPN host Pat McAfee has pledged to donate $250 for each of the next 1,000 individuals who complete the challenge.