"Bonner really does want this. He's working his butt off! He always says it's a whole new beast for him to tame. And it is," Sharna wrote in her Us Weekly blog of the 29-year-old 5'11" professional bull rider-turned-model.
"I can't push him physically any harder than I am because I want him to last in the season and I don't want him to be hurting so much that he doesn't enjoy the experience. I don't have the blessing of having an [NFL] athlete like [Rashad Jennings], who is in top fighting shape and who can run a routine for eight hours a day. I have to prioritize the time that I have with Bonner."
Bonner endured a near-fatal accident while bull riding in a January 2016 competition. He flipped off the backside of a bull and then got trampled by the wild animal, snapping his C2 vertebra in his neck.
Bonner was paralyzed for 24 hours and underwent a six-hour surgery, according to GQ magazine, but shocked the world when he was able to walk again three days later.
Doctors told Bonner that 95 percent of people with his injuries never walk again.
"Bonner looks physically fit and strong and you get distracted by that beautiful jawline, but he's broken on the inside. He went through a spinal fusion and he has metal holding his body together. He lives every day with pain and it makes it very difficult for him to dance," Sharna explained.
"With Noah Galloway, he was missing limbs so his injuries were very obvious. But Bonner's injuries are internal, so people tend to overlook how difficult this is for him. This man was paralyzed 12 months ago, and he's out there doing the cha cha when it took him two months to learn how to hold a spoon again."
Sharna said Bonner's story and amazing physical progress is "so inspirational" for people to watch. The pro dancer said she's never been one to back down from a challenge and Bonner "really is capable of so much."
However, Sharna admitted last week's Charleston routine was "a little rough." The pair tied with three other couples for ninth -- and last -- place on the Dancing with the Stars'judging leaderboard at 24 points out of 40 points.
"If I'm 100 percent honest, going into last Monday, I was unsure how it was all going to go. It was probably the most creative Charleston routine I could have created for Bonner while considering his physical limitations. I think that Bonner gets to the live show and struggles a little bit with the rush of adrenaline and the nerves," Sharna wrote in her blog.
"We haven't quite cracked the code yet. But every week is getting a little bit better. I don't want to say we were underscored -- there could have been a 7 or two thrown in there -- but I understand what the judges were saying."
"It's just tough -- the Charleston is a really difficult dance and it was really hard on someone like Bonner, who is really working hard to get back his coordination after his accident."
It's apparent the Charleston requires a lot of coordination, not to mention it's a physically-taxing dance.
"Even if we're not doing lifts and tricks, it requires you to throw out your arms and extend your legs and jump around and give really high energy. And all of that has an impact on Bonner's injuries and really fatigues him," Sharna revealed.
Dancing with the Stars' next episode airs Monday, April 10 at 8PM ET/PT and will feature the show's infamous "Most Memorable Year" theme.
Bonner and Sharna will be performing a foxtrot routine to the song "Feeling Good" by Michael Buble.