Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson/AFP Photo)

A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)

In this November 27, 2019 photo, Wadlande Pierre, right, talks on her mobile phone as she helps her mother, Vanlancia Julien, center, at their fruit and vegetable stand on a sidewalk in Delmas, a district of in Port-au-Prince, Haiti. Pierre, 23, said she temporarily moved in with her aunt in the southwest town of Les Cayes to escape the violent protests in Port-au-Prince. However, she had to move back to the capital because there was no gas, power or water in Les Cayes, and food was becoming scarce. (Photo by Dieu Nalio Chery/AP Photo)

Freshmen in Zhengzhou Institute of Aeronautical Industry Management head bottles of mineral water for upright stand during military training on September 17, 2015 in Zhengzhou, Henan Province of China. More than 6,800 freshmen in the school are required to take part in the military training. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

These images of young children training were taken at a gymnastics summer camp in Bozhou, Anhui province, China on July 28, 2015. Children with promise are selected to attend, and their families hope training will not only benefit their children physically but also increase ‘willpower’, according to China News Service. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)

Soldiers from Japan's Ground Self Defense Force come ashore in amphibious assault vehicle as they train alongside U.S. Marines during the bilateral annual Iron Fist military training exercise in Camp Pendleton, California February 26, 2016. (Photo by Mike Blake/Reuters)

A U.S. army soldier exercises in front of a M270A1 multiple launch rocket system as they prepare for a live-fire training exercise of the 6-37th Field Artillery Regiment at a training area near the demilitarized zone separating the two Koreas, in Cheorwon, South Korea, March 9, 2016. (Photo by Kim Hong-Ji/Reuters)

Children attend a swim training session at Hangzhou Chen Jinglun Sport school Natatorium, where Chinese Olympic swimmer Sun Yang and Fu Yuanhui also trained, in Hangzhou, Zhejiang province, China, August 10, 2016. (Photo by Aly Song/Reuters)