Making the jump to varsity football can be so frightening and humbling, that it often takes even a prolific junior varsity player a year to break out again.

Not so for Napa High running back Cody Jensen. The junior had only one  tough start — a 12-carry, 24-yard debut in a season-opening loss to Vista del Lago — before he started dominating like he had as a JV rusher last year, recording the first of his four 100-yard rushing games at Merced in Week 2.

Jensen’s indoctrination hasn’t come without pain. He’s absorbed more knockout hits than any teammate, yet still has managed to lead the Indians in both rushing (with 795 yards, 7.7 per carry and nine touchdowns), and receiving, with 18 grabs for 269 yards and three TDs.

While taking head coach Troy Mott’s advice to run track last spring certainly helped with Jensen’s open-field speed — he hasn’t been caught yet — the snowboarding he loves to do might be one key to his being such a fearless varsity rookie.

“The saying for snowboarding is ‘Go big or go home,’ and it’s the same thing with football,” Jensen said. “If you don’t put yourself out there to get hit, what’s the point of playing? You’ve got to expect to get hit hard and get up. I try not to hurt myself (when snowboarding) because football’s my main sport, but I think the ‘no fear’ aspect of it resembles football.”

At Casa Grande-Petaluma in Week 4, Jensen took a few seconds longer than usual to get back up after an 8-yard run in the third quarter. After a few minutes rest, thanks to a teammate’s fumble that set up a Gauchos score and 32-18 lead, Jensen’s best series of the night — six carries for 37 yards — helped the Indians cut their deficit back to seven points.

“There’s been a couple of good hits, and of course there’s pain involved,” Jensen said. “But my dad told me pain is a way of releasing stress, and for some reason getting hit pumps me up. When you get those good hits it just motivates you to come back harder. Of course I’m not going to go head-up with a lineman because they’re bigger than me. But if I have a chance to run somebody over, that’s fun.”

Few 5-foot-9, 162-pounders could say such a thing.

“Despite his small stature, he packs a punch when he runs,” Mott said. “He has a great burst, which he has had since his freshman year, but he’s added speed endurance to his game through track. He catches the ball real well and is our best route runner because he has the ability to separate from defenders. He is a guy who was already blessed with some skills and has taken the initiative to get better, and now it is paying off for him.”

Mott said Jensen likes to deliver his own hits, not only as a ballcarrier but as a blocker.

“Even with his slight build, he gives all of his 165 pounds to protect for our quarterback,” the coach said. “He runs just as hard at practice as he does in the game, and I actually have to shut him down sometimes at practice so we can save his legs for Friday nights.”

Jensen actually got his first varsity touchdown as a JV pull-up, on a 2-yard run near the end of last year’s 33-13 Sac-Joaquin Section Division I playoff quarterfinal loss to visiting Laguna Creek. He had just seven yards in five carries that night, making the decision easy when Mott suggested he try track.

Jensen ran the opening leg for Napa’s varsity boys 4x100 relay team, and the quartet advanced all the way to the section meet.

“I was really surprised with the speed of varsity last year, but this year I got faster doing track and caught up with the speed instead of letting the speed catch up with me,” he said. “I wanted to work harder to get faster than everybody.”

Jensen got his chance in the playoff game because then-juniors Logan Hess and Charles Boyett, last year’s rushing leaders, were too banged up to continue running the ball. It was a sign of things to come. Hess and Boyett were out for the season with knee injuries by Week 5 this year, leaving Jensen to carry most of the load himself.

“Since the injuries to Charles and Logan, Cody’s learning curve has had to speed up,” Mott said. “But he is very bright and learns new concepts very fast. His confidence continues to grow. He has always been confident, but obviously success breeds more confidence.”

Helping Jensen is another varsity rookie, quarterback Cody Thompson, who has stepped up in Boyett’s absence and provided balance to the Indians’ offense — behind an offensive line also made up mostly of juniors.

“The offensive line is the heart of the team, in my opinion,” Jensen said. “If you don’t have an offensive line, you don’t have a quarterback handing off the ball to a running back, and to have a good offense, you have to have a good defense. Everything stems from one another.

“Since Charles was such a good runner, we were a running team. It’s not good that Charles is out now, but it’s good that we throw more because most teams don’t expect that from us. It seems like we (juniors) have all grown up together these past couple of years, just all getting better together, and it’s really cool.”

The spotlight hasn’t turned Jensen into a diva. He is very cordial with the media, telling reporters to “have a good day” after interviews.

Mott said he’s just as respectful around his coaches and peers.

“He is a pleasure to have around,” the coach said. “He takes both praise and criticism with an even keel, and really works hard to improve his game. He is very strong and has a big commitment to the weight room and his conditioning, and I really appreciate him taking my recommendation and working in the spring with the track team. It showed me he was serious about being great. If more guys would follow his lead, it will really help with our team speed and our athleticism.”

Jensen said his focus is on winning, not his stats, and it’s helped him accept his elevated role.

“There’s somebody else in front us — that’s what our coaches are teaching us,” he said. “It doesn’t matter what happened last week. We’ve got to step on the team that’s ahead of us.”

Cody Jensen File

Favorite athlete: Jerome “The Bus” Bettis, bruising former Rams/Steelers halfback, fifth-best NFL all-time rushing leader

Favorite foods: Penne pasta with chicken and tomatoes; Chinese food

Favorite book: “The Lost: A Search for Six of Six Million,” by Daniel Mendelsohn

Favorite movie: Curious George

GPA: 3.3 to 3.8

Career plans: Veterinarian or sports agent

Parents: Jeni Jensen and Michael Cox