A race on foot; a running competition. Often used in contexts like track and field or informal races.
I participated in a footrace at the sports day.
競走 is a general term for a race, while 徒歩競走 specifies a race on foot.
マラソン refers specifically to a marathon, a long-distance footrace, whereas 徒歩競走 can be any footrace.
Compound of 徒歩 (toho, 'on foot') and 競走 (kyōsō, 'race').