Inactive Tutor answered 03/28/19
Greetings!
This would most likely be "push" because they are pushing themselves suddenly to get ahead of the competition and cross the finish line. Effort does not work because it implies they were not giving it their all to begin with. Outburst sounds more in line with verbally interjecting something. Force sounds close but does not give the full "umph" as the word "push" does when it relates to the word "spurt".
Hope this helps and have a great week!
Brandon