Vikings’ Justin Jefferson ‘feeling confident’ about preventing another hamstring strain

Vikings receiver Justin Jefferson, their biggest star and the NFL’s highest-paid non-quarterback who signed for $35 million per season this summer, has been under the team’s microscope since missing seven games because of a hamstring injury last season.

For good reason: Hamstring strains remain the league’s top reason for missed games over all other types of injuries. The NFL has committed millions of dollars to study the causes and effects of hamstring strains and their recurrence because they so often return and nag players.

The Vikings and Jefferson have taken significant steps this offseason to prevent re-injury. His hamstring strain suffered Week 5 at U.S. Bank Stadium was deemed “high grade.”

“I’m so scared for it to happen again that I’ve been overly cautious about it, just trying to take care of my body in the right way, just trying to find new things that I can implement in my day-to-day life that can better help me throughout the season,” Jefferson said earlier in training camp. “I’ve definitely been working on my hamstrings a little bit more, making sure that I’m injury-proof.”

Jefferson said he has spent more time in the weight room, focused on exercises that strengthen both hamstring muscles equally. The Vikings’ medical staff has kept a closer eye on his mileage during practices, tracked through radio frequency identification (RFID) chips in everyone’s shoulder pads. They’ve evaluated how many yards he runs, the time he’s spent running, his acceleration, and his weight before and after practices.

Earlier this month, the data told the team that Jefferson needed a day off from practice.

“I like it and I hate it at the same time, just because I never was the type of person to take days off,” he said.

That was the only forced rest day the 25-year-old superstar required this summer.

“I’m feeling confident going into Week 1,” Jefferson said Thursday.

Jefferson wasn’t so confident after hearing a “pop” while running a route in the Oct. 8 loss against the Chiefs. It was his first significant injury since high school. He had played in 55 straight games to begin his NFL career at that point.

But he’s not alone. Rams receiver Cooper Kupp and Packers receiver Christian Watson are among the many NFL players to recently miss extended time because of strained hamstrings.

“The hamstring remains our number one burden injury,” said Dr. Allen Sills, the NFL’s chief medical officer. “Meaning players miss more time on field as a result of that injury more than any other injury – more than concussions, more than ACLs. It’s something we have to continue to look at and continue to work with our clubs to reduce incident and recurrence.”

The NFL is trying to help all teams. Starting last summer, the league shortened “ramp-up” practice periods, including the first four days at camp and the first four days of padded workouts. That led to a 29% decrease in all leg muscle strains in 2023 training camps.

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More answers are coming.

A four-year study of hamstring prevention and treatment, commissioned by the NFL through a $4 million grant and led by University of Wisconsin researcher Dr. Bryan Heiderscheit, will conclude after this NCAA football season. More than 660 athletes from D-I programs at BYU, Notre Dame, Indiana, Wisconsin and North Carolina have had their baseline sprint mechanics studied and, upon suffering hamstring injuries, monitored via MRIs and strength tests.

Recurrence is all too common with hamstring injuries and recoveries.

“What we see consistently is it’s a double-edged sword,” Heiderscheit said. “In order to get back to full performance, you have to sprint as hard as you can. But to sprint as hard as you can, you have to be fully recovered.”

Heiderscheit recommends that athletes ensure their recovering muscles are well conditioned before ramping up activity. Research has found that athletes require 50% more energy in the muscle during acceleration from 80% to 100% full speed. The hamstring is particularly tricky because it crosses both knee and hip joints, which pull the muscle in different ways.

Knowledge of recovery has come a long way since Heiderscheit began studying the muscle strains in athletes over a decade ago.

“Early on, it was rest, don’t do anything,” Heiderscheit said. “Now we know that’s one of the worst things you can do. You need to get moving and moving pretty darn quickly.”

But not too quickly. While recovering from his injury last season, Jefferson practiced for about a month before returning to game action. The slow return was necessary for a high-grade strain that had a recovery timeline of about eight to 10 weeks.

The mental hurdle is another challenge for athletes.

Vikings receiver Jalen Nailor was already in the trainer’s room nursing a hamstring injury suffered Sept. 14 in Philadelphia when Jefferson joined him a few weeks later.

Nailor missed seven games. In his own head, it took longer to feel fully recovered.

“I knew that I was good,” Nailor said. “But I wasn’t trusting it until a couple weeks later.”

Jefferson hopes the offseason emphasis has put his worries in the past.

“I’ll get to the point where I feel like I’m not going to think of it again,” Jefferson said, “just because I feel like I’m going to push it to where it’s way strong enough for it not to happen again. It’s all about having the confidence in it and I can go out there and play freely.”

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