noun
travelling on foot; journeying on foot; hiking
A somewhat old-fashioned or literary term for traveling on foot, often with a lighthearted or rustic feel. The expression comes from the image of one's knees (膝) being the 'chestnut horse' (栗毛) that carries you.
昔の旅人は膝栗毛で江戸から京都まで歩いた。
Travelers in the old days walked from Edo to Kyoto on foot.
膝栗毛で山道をゆくの
It's not bad to go along the mountain path on foot.
歩き is a general word for walking; 膝栗毛 specifically evokes the idea of a journey made entirely on foot, often with a sense of endurance or rustic charm.
Literally 'knee chestnut horse', a humorous metaphor likening one's knees to a horse that carries the traveler. The phrase was popularized by the Edo-period comic novel 東海道中膝栗毛 (Tōkaidōchū Hizakurige).