After awhile, Peter can feel the muscles in his legs start to burn. He probably shouldn't have started at such a rough pace and now he's regretting it. On patrol, he was mostly swinging around; yeah, there was occasionally chasing after someone on foot, but for the most part, he was web-slinging around. His arms and his core got way more use than his legs, and it was stupid of him to assume that hours of patrolling New York would somehow qualify him to go on a 50-mile run with Alec at 6 in the morning.

Still, he pushes through it, though Peter's place slows a tad. Not enough that his pace isn't still a run, but enough that Alec would notice it.