[4] Espinoza won her first international competition in taekwondo at the 2003 Pan American Youth Championship in Rio de Janeiro.

She won the 2007 World Taekwondo Championships in the Middleweight (–72 kg) category defeating Lee In-Jong and also won the gold medal at the 2007 Pan American Games in the Heavyweight (+67 kg) category, defeating Brazilian Natália Falavigna in the final.

She began with a victory over Tunisian Khaoula Ben Hamza by a score of 4–0, later she beat Swedish Karolina Kedzierska 4–2.

She beat Sorn Davin in the first round before losing to eventual gold medallist Milica Mandić in the quarterfinals.

[10] Espinoza is a member of the Mexican Army with the rank of Cabo (Corporal) auxiliar de Educación Física y Deportes.