Kirui spent most of his early years competing on the track, and was fairly successful on the national stage in the 10,000m race. Beginning in 2015, though, he started moving to the roads, specifically in half marathons. He then ran his first marathons in 2016, eventually leading to his victory in Boston in 2017. The win in Boston was certainly a breakthrough for him, and he went on to win the marathon IAAF World Championships in London in 2017.
Kiplagat took home first place at Boston the first time she ever ran the race. She began running full time when she was just 16 years old, and in Kenya she is sponsored by the police force, but her family also owns farmland where many Kenyan runners train. Meanwhile, she raises two of her own children, and also graciously raises her sister's two children after her sister passed away from breast cancer, and she just adopted another child whose parents passed away. Even with all of that on her plate, Kiplagat manages to excel in professional running, and with her Boston win in 2017 she is the oldest woman ever to run under 2hrs 22mins in the marathon.