He is lean and sinewy, with muscular
He is thinly clothed – he leans forward as he runs
With lightly closed fists, and arms partially rais’d
On a flat road runs the well-train’d runner; (visual imagery). It depicts a professional runner who tries through the flat land on his run, but it is also seen that it focuses on the middle or lower class of people made up of common laborers. The "flat land" that he is running across can depict the poet’s birthplace as a whole.
He is lean and sinewy, with muscular legs; (visual imagery). I describes the runner is so strong.
He is thinly clothed – he leans forward as he runs, (visual imagery, kinesthetic imagery). It points out to the reader that the runner is ahead of his time (having advance) because of the specialized athletic clothing he is wearing. This depicts the advancement of the poet’s birthplace. It probably represents an advancement because at the time in which the poem was written, thin, breathable running clothes were not really invented yet.
With lightly closed fists, and arms partially rais’d. (visual imagery). It apparent the advancement. As any distance runner knows, the arm drive is a very important piece in a good stride not only to make it more efficient, but also to move the body along with greater ease.
So, the runner is using the advanced technique shows that he is not only a strong runner, but he is knowledgeable about his skill. The runner's skill and knowledge goes along with advancement. For example, as the Industrial Revolution hit, workers had to become more skilled at their jobs, or they may be replaced with machines. This is a great advancement in the skill of workers that happened in the poet’s birthplace because of the advancement in technology just as the runner depicts.