Jon Christenson is studying to be a doctor, so the Gophers senior knew the compound leg fracture he suffered in 2013 was career-threatening the second he saw his ankle dangling from the end of his left leg. ¶ “I didn’t know if I was going to walk again. I didn’t know if I was going to run again,” Christenson said. “I sure didn’t know I was going to play Division I football again.” ¶ Fellow Gophers offensive lineman Brian Bobek had his own harrowing experience that same year. During spring practice, he came down with extreme exhaustion and an irregular heartbeat. Doctors diagnosed him with viral myocarditis, an infection of the heart that could have been debilitating if left untreated.

“It was pretty shocking to say the least, especially being only 20 years old at the time,” Bobek said.

The road back to full health was grueling for both players, but Christenson and Bobek plowed through every obstacle. Now, both are positioned to start this season, with Bobek at center and Christenson next to him, at left guard. Both must finish training camp strong, however, as the battles for playing time along the offensive line remain intense.

“That’s one thing about the O-line: Even though there’s competition, we’re all still really good friends,” Christenson said. “And I think fighting through all those trials really enhances that respect. We see each other battle through stuff, and it’s like, ‘Wow, that’s a pretty cool dude.’ ”

Steel rod and screws

Zach Mottla started three games at center for the Gophers in 2012 before a compound leg fracture ended his career. Christenson took over and started the first nine games of 2013 before suffering a similar injury at Indiana.

A Hoosiers defensive tackle came crashing onto Christenson’s planted left leg, breaking his tibia in two places and his fibula in one, a few inches above the ankle.

“My mind immediately went to Zach Mottla,” Christenson said. “When I lifted up my leg and my whole ankle complex hung down, I knew immediately there’s no structure left in my shin. I knew this could for sure end my career because it did his.”

Christenson always had a fallback plan. He had walked on with the Gophers out of Minnetonka and dived into work toward his undergraduate degree in biochemistry. He’s now married and finishing his master’s degree in public health administration. He hopes a big senior season with the Gophers vaults him into the NFL before he eventually heads to medical school.

But his football goals seemed distant when doctors drilled a hole down the middle of his tibia, inserting a steel rod and fastening it with screws. Last season, with his leg setting off metal detectors, Christenson still played 12 games, mostly on special teams.

“It definitely was painful,” Christenson said.

Doctors removed the rod last winter, and he sat out from spring practice to rebuild strength. These days, he wields the rod like a trophy, happy to show it to anyone who asks.

“For one thing, my leg’s actually lighter,” Christenson said. “It’s like if you strapped a one-pound weight to your foot. I’m more agile without it and have quicker feet, which is actually huge for an offensive lineman.”

Two recoveries

Bobek’s agility and strength were big reasons why then-Ohio State coach Jim Tressel offered him a scholarship to play for the Buckeyes out of suburban Chicago.

Tressel resigned before Bobek’s freshman season, but with Luke Fickell serving as interim coach in 2011, Bobek still lettered and played in two games. After that season, Bobek transferred to Minnesota, passing up a chance to play for Urban Meyer.

“It was really the coaches here that made me decide to come here because I love Coach [Jerry] Kill and Coach [Matt] Limegrover and what they’re about,” Bobek said. “It reminded me a lot of what the coaching staff was at Ohio State when I first got there.”

Bobek sat out 2012, under NCAA transfer rules, but he would have been one of the leading candidates to start at center for the Gophers in 2013. Then came the viral myocarditis. It was a six-month recovery, and doctors strictly prohibited exercise.

“It was frustrating at times because I wasn’t allowed to work out or do anything that would be too strenuous on my heart,” Bobek said. “I had a lot of anxiety, and I couldn’t relieve stress like I normally would.”

Myocarditis, or inflammation of the heart, can cause long-term scarring, which can reduce the heart’s capacity. Bobek said he was fortunate not to have any scarring or long-term effects.

He played in three games last season before tearing a medial collateral knee ligament in the Northwestern game. It was another tough break, but Bobek needed time to retool his body anyway.

Now, Bobek said he is in the best shape of his life. He applied for a medical hardship waiver, which if approved would give him an additional year of eligibility for 2016. Bobek already has his undergraduate degree in business and marketing education. The extra year of eligibility would let him complete his master’s in applied kinesiology while still on scholarship.

“He’s one tough guy,” Christenson said. “He runs into one obstacle after the next. He’s an incredibly strong person, physically — maybe one of the strongest on the team — but then also mentally. I have the utmost respect for him.”

Bobek feels the same toward Christenson, who lines up inches to his left on each snap.

“Jon’s a guy who looked at [adversity] the same way I did,” Bobek said. “He looked at it positively and learned lessons from it. When things like that happen, it stinks, but if you deal with it the right way, you can really turn things a lot more positive than you would think.”