In the NFL, injuries are a part of the game.

With the size and speed of the players, collisions are practically certain to lead to injuries. But over the course of a 21-month period, the Falcons lost four key players with ruptured Achilles tendons.

“Injuries, I believe are cyclical,” Falcons coach Mike Smith said after a recent practice. “I don’t think you can ever have enough data. When you are talking about 1,800 players it’s really tough to have a scientific study. But, unfortunately we had the Achilles injuries last year that really affected us.”

On June 10, linebacker Sean Weatherspoon and wide receiver Julio Jones were jogging off to the side with the trainers when Weathespoon ruptured his Achilles tendon.

Weatherspoon’s injury occurred six months after defensive tackle Corey Peters, who was having his best season, went down in the 15th game of the season against San Francisco on Dec. 23.

Just three months before Peters’ injury, outside linebacker/defensive end Kroy Biermann ruptured his right Achilles and rode off the field at the Georgia Dome on a golf cart Sept. 15.

A little over a year before, former cornerback Brent Grimes ruptured his Achilles in the season opener against Kansas City.

“I wish that I could say all injuries are preventable, but that’s not the case when you’re playing football,” Smith said. “I think that you can see most of the time, Achilles injuries are non-contact injuries.”

There doesn’t appear to be a pattern for how the Falcons’ Achilles injuries have happened.

“We had one this offseason in which the players was working about half-speed with our athletic performance department,” Smith said. “There were others that happened in games. Most of the time, when you see those injuries occur, they look different every time. … Unfortunately we’ve had a number of them in the last few years.”

Last season, there were 17 ruptured Achilles in the NFL. So far through training camp, there are eight players who have been declared out for the season with ruptured Achilles, including New York Jets linebacker Jermaine Cunningham, who played at Stephenson High.

“I’m not sure if there is any known factors as to why it happens,” said Dr. Phillip Kwong, a foot and ankle surgeon at Kerlan-Jobe Orthopaedic Clinic in Los Angeles. ”There may be some possibility that guys are bigger and stronger.”

The playing surface may be a factor. The Falcons try to practice on grass as much as possible. When they have to go inside because of the rain, they practice on turf and play their home games on turf.

“I don’t know the way the surfaces are and the way the shoes are designed if there is more traction when they do explosive movements, when they stop and go the traction, the shoe and the turf, they may have an affect on the tendon,” Kwong said.

The offseason training programs, with the push to become bigger, stronger and faster, may be putting too much stress on the tendons.

“The elite athlete, these guys work out year round, but sometimes with that workout schedule, the tendon gets over-used,” said Dr. Sameh A. Labib, associate professor of Orthopaedic-Surgery at Emory University’s School of Medicine. “When you go out there and go beyond what the tendon can take, it can rupture.”

For Peters, the pain was excruciating in the game against the San Francisco 49ers.

“It’s just snapped,” Peters said. “It’s definitely something that I wouldn’t recommend anybody to go through.”

Weatherspoon was writhing in pain as he left the field with the aid of Jones, who was working out with him.

Like most football injuries, the ruptured Achilles is not preventable.

“Basically, you stay limber, you do your stretching, you do an MRI or an ultrasound if you’re sore,” Labib said. “Then, if you see on the MRI that you have tendon degeneration, meaning the tendon is getting weak, then you can inject it with … cells and then maybe you can revive it a little bit.”

While the injury is not preventable, there are some precautions that can be taken.

“Usually, if you start to develop some pain in the Achilles area before you’ve actually torn it, there are a couple of different ways that you can treat it,” said Dr. Alexis Colvin, an associate professor of sports medicine at Mount Sinai Hospital in New York.

“There are certain types of strengthening exercises that you want to do for the calf muscle. Because the Achilles tendon connects the calf muscle to the heal bone. You can also try a heel lift.

“Part of it, unfortunately, is working to limit the lower-leg activities, which is not always possible in elite athletes. Those are the sort of things you would do if you ever started feeling that pain initially.”

Grimes recovered and signed with the Dolphins. He played well enough after his surgery to make the Pro Bowl last season.

Biermann doesn’t appear to have lost a step as he’s battling back. Peters is running on the side with trainers and hopes to return by the start of the season.

Weatherspoon recently had surgery and has started his rehab process. He’s set to accept an unofficial coaching title and help coach the young linebackers while he’s rehabbing this season.

The group of players have shared stories with each other. Biermann passed on what he learned from Grimes. Peters has had Biermann to lean on, while Biermann and Peters will be on hand to help Weatherspoon.

“I think that more than anything, the previous guys have been like a shoulder to lean on,” Peters said. “They’ve been able to be very supportive toward me. Everybody has a better understanding of it because they’ve dealt with it.”

Peter said he’s been diligent with his rehabilitation training.

“For me, it’s a very important tendon,” Peters said. “We are trying to get it very strong. It’s probably stronger than my other one at this point.”

Smith hopes to get Peters back in a few more weeks and Weatherspoon next season.

“The guys have done a great job in the rehabilitation part,” Smith said. “Historically, it has taken guys nine to 12 months to get back. We are way ahead of schedule with both of our guys in terms of getting them back.”