SANTA CLARA – In the early days of training camp, the data revealed a downward trend among the 90 players on the 49ers’ roster.

Many of the players reported muscle soreness, a common experience during the early days of practices. Typically, fatigue in training camp is viewed as common as afternoon practices in a blazing sun. It’s just part of the deal.

But Mark Uyeyama, the 49ers’ director of human performance, compiled the data, and met with coach Chip Kelly to talk about the issue. After being briefed on the situation, Kelly cut short the following practice from its planned length and intensity level.

“There’s a lot of running, but he (Kelly) controls it,” 49ers wide receiver Torrey Smith said. “It’s the first time I’ve been around somebody who has different styles of practices. He has different coded days or color days for different amounts of time.

“Through the CBA you can only have three-hour practices. He has sensors that track our running, and some days he’ll dial it back or pick it up a little more. We never go the full three hours. Our max is two.”

Kelly proved to be a controversial figure during his three seasons with the Philadelphia Eagles. His approach was often viewed as unorthodox. Players supplied daily urine samples so the team could track their hydration status. In a Washington Post feature, one former player called Kelly’s requirements, “Orwellian."

Tight end Garrett Celek’s big brother, Brent, played all three seasons for Kelly, so the he had an idea of what to expect.


“I remember he said always in the morning they had a heart-rate monitor that they put around their chest and hooked up to their phones,” Celek said. “They also did urine test for hydration.”

The 49ers do not use urine tests. Now, the desired data is collected in less-invasive ways.

The team has 12 kiosks – nine in the players’ lounge and three near the cafeteria – designed to collect information on each player every morning. Each player steps on a scale to record his weight. Then, he’s asked four general questions, such as, “How sore do you feel?” The player responds using a 1-to-10 scale.

Then, the player takes a seat and attaches a sensor to his small finger to measure his heart rate variable (HRV).

According to 2015 report in Global Advances in Health and Medicine, a professional journal, the time intervals between adjacent heartbeats is “directly related to the body's interdependent regulatory systems and ultimately, their efficiency and health.”

“I like it because it gives you a chance to keep track of your progress each day,” 49ers linebacker Michael Wilhoite said. “You know if your HRV or your weight and the way you’re feeling is up and down, you don’t have a good routine and you’re not being consistent with your activities off the field and your recovery routine.

“It tells me if my weight is staying the same every morning when I come in, and my HRV is around the same number, I’m eating right, I’m keeping the same routine every day, I’m doing the right things I need to do.”

“The day I’m feeling my best,” Celek said, “it reads a certain number. If it’s too high or too low, I know there are things that I need to do to get it back to normal and make sure I’m getting back to the best of my ability.”

The combination of objective and subjective data generally requires players to spend up to four minutes at a kiosk. The resulting information is viewed as a starting point to open lines of communication from the players to Uyeyama and his staff.

Each player wears a radio device that acts similar to GPS to track and record their movements during every practice session. For instance, during one recent practice, offensive linemen covered an average of 2,228 yards during a session, while the wide receivers ran an average of 3,584 yards.

“We get email push notifications every day to monitor it,” 49ers tight end Vance McDonald said. “How many yards you’re running on the field. What’s your top speed? We turn it into a competition.”

Said Celek, “We compare who ran the most and who had the top speed. It shows how often you’re working at your hardest, how many explosive efforts you had, how many cuts you had. We all compare it to each other.”

The 49ers are winding down a training camp that seemingly had few players sit out due to muscle strains.


One exception, of course, is quarterback Colin Kaepernick, who was sidelined for 11 days due to arm fatigue. After resting and regaining his arm strength, Kaepernick returned to full practices this week. He is expected to see important playing time Friday night against the Green Bay Packers at Levi’s Stadium as he competes with Blaine Gabbert for the starting job.

Wide receiver DeAndre Smelter is the only other player who missed significant practice time due to a muscle-related condition.

The response from players to the monitoring of their bodies has seemingly been positive.

“A lot of times you go out and you might pull a hamstring or tweak a muscle,” 49ers veteran safety Antoine Bethea said. “What we have going on right now, it has a hold on how your body is feeling, so you’re not the only person who’s looking at it. You have the training staff, the strength and conditioning people. There are multiple eyes looking at the assessment of your body and honing in on if you need to take a break or you’re taking too many reps -- whatever the case may be to keep you healthy.”

Bethea said he heard the same complaints about Kelly’s information-gathering in Philadelphia being too invasive. But he has not found that to be the case with the 49ers.

“Some things might be tweaked and changed a little bit,” Bethea said. “But for the most part, I think it’s great. Chip has numerous people come in and speak to us about health and recovery. With Chip, that’s a big thing. Go out and work hard, but at the end of the day, you also have to recover. I think this has been great for us.”

At the end of each daily email assessment, players are given a suggested plan for the day. It concludes with a recommendation that all screens – smart phones, iPads, TVs – are powered down 90 minutes before bed. The ideal temperature to sleep in a completely dark room is from 68 to 72 degrees.

“I don’t do it every night,” Celek said. “Sometimes I’m on the phone with my wife on Facetime. She’s back in Ohio. But if I can, I do it. At night I’m studying my playbook on my iPad. It’s kind of hard. But when I do everything I’m supposed to do, absolutely, you can tell a difference. If you want to go to bed at 9:30, just make sure everything is turned off by 8.”

The 49ers’ interest in sports science pre-dates the 49ers’ hiring of Kelly to replace Jim Tomsula, who was fired after just one season. Uyeyama worked with PUSH, a sports technology company based in Toronto, to exchange ideas in hopes of developing a useful tool to monitor and track the health of players.

The kiosks were installed for the beginning of the offseason program and quickly became a part of each player’s daily routine.


“A lot of the things he added we were already doing here,” said Smith, a six-year NFL veteran. “It’s not like it’s an adjustment for us. He fit right in. Chip just added another dimension to it. It’s the smoothest camp I’ve been around.”

And those typical long practices in the heat of the day are a thing of the past, too. Santa Clara’s high temperatures do not rival Rocklin or Stockton for severity, and Kelly implemented practices this summer that began at 10:25 a.m., when their minds and bodies are fresh off a good night’s sleep.

Some players want to know more about how to get the most from their bodies. But there is also the mental reassurance that they are doing everything to maximize their abilities.

“I’ve learned a lot more about my body than I’ve ever known,” Celek said. “I know what I should eat, shouldn’t eat, how much I have to drink now and how much sleep I really need to get.

“If you feel like you’re not doing all you can do to be good, that might stress you out. If you know that every day you’ve done everything possible, then that’s a lot of weight off your shoulders and mentally you feel a lot better.”