In Parshas Vayeitze, Rashi comments on the words דרך שבעת ימים, quoting a midrash, saying
כל אותן ג' ימים שהלך המגיד להגיד ללבן הלך יעקב לדרכו, נמצא יעקב רחוק מלבן ששה ימים, ובשביעי השיגו לבן. למדנו שכל מה שהלך יעקב בשבעה ימים הלך לבן ביום אחד
He explains that Yaakov started three days away from Lavan and he had a three day head start on him as he was walking away from him, so Yaakov was 6 days ahead. And Lavan caught up to him on the seventh day, implying that Lavan covered in one day what Yaakov covered in 7 days.
This doesn't seem to make sense to me. Lavan left on the fourth day, so it seems to me he was walking not 1, but rather 4 days by the time he caught up to Yaakov. That would mean he was moving roughly twice as fast as Yaakov, which seems completely reasonable since he wasn't laden with children and animals in his pursuit. How does Rashi's statement that Lavan was moving 7 times as fast as Yaakov work?