Team Strong Silvers member Ngai Hin Kwok, 66, works out as teammate Ng Siu Chi, 57, watches at a stadium in Singapore March 15, 2015. Team Strong Silvers, is a group of senior citizens who train in calisthenics. The trio trains individually at least three times a week, and meets up for joint calisthenics at least twice a month. (Photo by Edgar Su/Reuters)

In this Monday, July 25, 2016 photo, skydiver Luke Aikins smiles as he jumps from a helicopter during his training in Simi Valley, Calif. After months of training, this elite skydiver says he's ready to leave his chute in the plane when he bails out 25,000 feet above Simi Valley on Saturday. That's right, no parachute, no wingsuit and no fellow skydiver with an extra one to hand him in mid-air. (Photo by Jae C. Hong/AP Photo)

South Korean university students prepare for an establishment ceremony of the Reserve Officer Training Corps (ROTC) for female cadets at Sookmyung Women's University on December 10, 2010 in Seoul, South Korea. The South Korean defense ministry has agreed to admit women into it's college-based Reserve Officers' Training Program for the first time since the program began in 1963. (Photo by Chung Sung-Jun/Getty Images)

A member of security forces takes part in a training session arranged by a security company in Tajoura suburb of Tripoli, Libya on February 10, 2021. (Photo by Hazem Ahmed/Reuters)

A girl practices martial arts during a training at a school in Syrian opposition-held village of al-Jeineh, Syria on April 11, 2021. (Photo by Khalil Ashawi/Reuters)

Afghan resistance movement and anti-Taliban uprising forces take part in a military training in Panjshir province on August 30, 2021. (Photo by Ahmad Sahel Arman/AFP Photo)

A road is soaked in water following an earthquake, in Tokyo, early Friday, October 8, 2021. A powerful earthquake shook the Tokyo area on Thursday night, halting trains and subways. (Photo by Kyodo News via AP Photo)

Marines of the Baltic Fleet forces of the Russian Navy train in the zone of obstacles during military exercises at the Khmelevka firing ground in the Kaliningrad region, Russia on November 24, 2021. (Photo by Vitaly Nevar/Reuters)