Fort Jackson, SC — This past fall, three soldiers died after taking the Army physical fitness test during basic training at Fort Jackson, SC.

Pvt. Andrea Rosser, 21, of Raleigh, NC, collapsed and later died on Oct. 25, according to the Army Times and The State of Columbia, SC. Pvt. Dominique Brooks, 19, of Houston, died Sept. 25 after having a seizure on her barracks floor, and Pvt. Derryl Britt, 20, of Durham, NC, died Sept. 27 when he was taken off life support after surgery to repair a brain hemorrhage, according to media reports.

Rosser was one week away from completing the nine-week course. Her death is still under investigation.

"I think all of us are surprised both by the close time of their deaths but also by the young ages of the soldiers," Col. Brian Prosser, commander of the 193rd Infantry Brigade, told the Army Times.

Rosser's mother, Georgette, told the Army Times that her daughter died while attempting to pass the 2-mile-run portion of the Army fitness test, which also includes timed push-ups and sit-ups. This was Rosser's fifth attempt at passing the timed run, her mother told the Army Times. Soldiers have to run the eight laps in just under 20 minutes to pass.

During her fifth attempt, Rosser was on her final lap when she began showing signs of physical distress, according to an Army spokesperson. Rosser was still breathing and conscious when paramedics arrived. They performed CPR on Rosser on the way to a nearby hospital, but she was pronounced dead an hour later.

Aside from the three recent deaths, 22 soldiers have died over the past five years while assigned to the Army's five basic combat training centers, a spokesperson said. Of the eight deaths that occurred on duty, five were related to physical training or heat casualties. About 50,000 soldiers go through basic training and advanced individual training at Fort Jackson each year. About half of all soldiers and 70 percent of women entering the Army each year receive basic training at Fort Jackson.

According to a 2004 study in the Annals of Internal Medicine, unexpected deaths among recruits are rare throughout the U.S. military. From 1977 to 2001, only 126 of 6.3 million recruits who entered basic training died a sudden death, or a death that occurs unexpectedly or without trauma. Of the 126 deaths, 108 occurred during exercise, researchers found.

Before entering basic training, all recruits undergo a physical examination at one of several United States Military Entrance Processing Command centers, the Army Times reports. Recruits also have their medical history reviewed to look for any pre-existing medical conditions. The Army sometimes grants medical waivers to recruits with health conditions that could make them ineligible for service. The Army has not said if the three soldiers who died, Rosser, Brooks or Britt, entered the Army under medical waivers.