Green Bay Packers' Johnathan Calvin rides a bike to NFL football training camp on July 27, 2017, in Green Bay, Wis. (Photo by Morry Gash/AP Photo)

A couple shares a light moment in a Mass Transit Railway (MTR) subway train in Hong Kong, China on August 28, 2019. (Photo by Anushree Fadnavis/Reuters)

A Kenyan acrobatic member of the Mighty Jambo Circus Academy performs a stunt during their training routine at the academy in Nairobi, Kenya, 13 January 2021. (Photo by Daniel Irungu/EPA/EFE)

Two holidaymakers amuse themselves with a porter's trolley whilst waiting for their train at Euston Station, London, 5th August 1939. (Photo by A. J. O'Brien/Fox Photos/Getty Images)

Heimana Reynolds of USA in action during a training session prior to the World Skate Park World Championships at the Parque Candido Portin​ari in Sao Paulo, Brazil, 11 September 2019. (Photo by Sebastião Moreira/EPA/EFE)

Celera Barnes of the United States trains during a warm up session before the start of the World Athletics Indoor Championships at the Emirates Arena in Glasgow, Scotland, Thursday, February 29, 2024. (Photo by Bernat Armangue/AP Photo)

American paratroopers from the the 82nd Expeditionary Rescue Squadron take part in training for rescue operations in East Africa in the last decade of April 2024. (Photo by Senior Airman Olivia Gibson/US Air Force/CMA)

Members of the Hitler Youth who are trained to report airstrikes repaining their bicycles. Published by: “Die Sirene”. 1942. (Photo by Herbert Hoffmann/Ullstein Bild via Getty Images)