79 year old Constance Ngubane spars in the ring as she takes part in a “Boxing Gogos” (Grannies) training session hosted by the A Team Gym in Cosmo City in Johannesburg on September 19, 2017. The grandmothers, many of whom are over 70 have been training with coach Claude Maphosa and claim that they no longer suffer from the ailments they had before, and are stronger than ever. The grannies travel from all over Cosmo City for the twice weekly sessions. Coach Maphosa is in the process of planning events in other areas for grannies who have been inspired by the story, to join in. (Photo by Gulshan Khan/AFP Photo)

Members of the local Cossack community undergo military training at a boot camp set up by the Russkiye Vityazi (Russian Knights) military patriotic club in the village of Sengileyevskoye, south of Stavropol, March 22, 2015. A group of cossacks from the village of Kazanskaya, who are planning a professional career at the military intelligence service, has arrived at a camp for training under the leadership of professional instructors. (Photo by Eduard Korniyenko/Reuters)

Members of the Oath Keepers and general public return fire during a simulated attack as they take part in a tactical training session in northern Idaho, U.S. October 1, 2016. In April 2015 Reuters photographer Jim Urquhart was assigned to cover the Oath Keepers during a tour of the Sugar Pine gold mine in Oregon after the group of former cops, military, firefighters and other first responders had risen to prominence during a standoff in Nevada over land rights. (Photo by Jim Urquhart/Reuters)

Participants of the techno-parade “Zug der Liebe” (Train of love) dance on a street in Berlin, Germany July 25, 2015. The “Zug der Liebe” is the successor to the “Loveparade”, which in its heyday attracted up to 100,000 participants and ended in disaster and tragedy in 2010 when 21 people died and over 500 were injured due to suffocation from overcrowding at the “Loveparade” in Duisburg. (Photo by Axel Schmidt/Reuters)

Athletes attend training session at the Ak Bulak Nordic Arena outside Almaty, Kazakhstan, July 16, 2015. Kazakhstan is aspiring to host the 2022 Winter Olympics but many in the Central Asian nation view the bid as yet another vanity project of long-ruling President Nursultan Nazarbayev. Almaty, the financial capital, will go head-to-head with the Chinese metropolis Beijing on Friday when the International Olympic Committee elects the winner at its session in Malaysia. (Photo by Shamil Zhumatov/Reuters)

Brazilian gymnast Jade Barbosa is seen during a training session at the new Brazilian Artistic Gymnastics Center in Rio de Janeiro January 16, 2015. The Artistic Gymnastics Center is where gymnasts are preparing for the 2016 Olympics. (Photo by Sergio Moraes/Reuters)

Sara Takanashi of Japan, Maja Vtic from Slovenia and Germany's Carina Vogt (R-L) prepare for a training session of the women's Individual normal hill HS100 ski jumping at the Nordic World Ski Championships in Falun February 18, 2015. (Photo by Kai Pfaffenbach/Reuters)

Thailand's badminton player Ratchanok Intanon, who hopes to win gold at the Rio Olympics, receives a massage during a morning training session at a gym in Bangkok, Thailand, June 22, 2016. As the humble daughter of factory workers at a Bangkok sweet-maker, badminton was a ticket out of poverty for Ratchanok Intanon, who hopes winning gold at the Rio Olympics might inspire more Thai girls to chase their dreams. (Photo by Athit Perawongmetha/Reuters)