This is Caroline Wozniacki of Denmark. Caroline is current ranked number one in the World by the WTA. Here she is experiencing Fiero after victory. Fiero is a specific and intense emotion of accomplishment after overcoming a great obstacle. It is certainly not limited to athletic events, but these are commonly photographed. It can also result from overcoming emotional, financial, family, or business obstacles. There is no equivalent word for this in English. Fiero is a term coined by Italian psychologist Isabella Poggi.
The facial expressions and body posture of fiero are interestingly similar to those of extreme pain. Note Caroline's eyes are closed tightly, and her mouth is open wide. If the picture were wider in angle - you would see her fists clenched and if it had audio, you would hear the tennis star screaming. Yet when we see this picture, even though at this writing, her winning this match is about three week old, we not only easily make the distinction that she is experiencing extreme fiero - but we feel it too.
The fact that we truly feel a bit of Ms. Wozniacki's fiero, or that of any winning athlete, or we cry during a sad movie, or feel pain when we witness another being injured - are all indirect evidence for the existence of our "Mirror Neurons".
Mirror neurons are a new class of neurons first discovered in monkeys about 20 years ago and have since been found in birds, dogs and humans. Many experts feel that defects in these neurons play a key role in the development of autism, sociopathic and psychopathic behavior, and perhaps such defects are at the root of much criminal behavior. The same experts feel that healthy mirror neurons also enable us to learn. A better name for mirror neurons may be "empathy neurons".