“Sixteen healthy male participants donated their body odor while engaging in a boxing session […]”
An unusual occurrence perhaps, but less so if you were organising an experiment to investigate whether the body odor of a stranger with the intention to harm serves as a chemosignal of aggression.
see: ‘You Smell Dangerous: Communicating Fight Responses Through Human Chemosignals of Aggression‘ in: Chemical Senses (2016) 41 (1): 35-43.
Question [optional]. How would you go about collecting body odor during a boxing bout? [substantial help with answers may be found here]
The photo shows lead author Smiljana Mutic of Uniklinik RWTH Aachen, Germany.