Trying to increase turnover in general and improve mechanics at faster (VO2-ish) paces in particular. I know NAU did - maybe they still do? - large quantities of 300s. Mike Smith also mentioned in a Letsrun interview about coaching Rupp a 24x400 workout. I would kind of prefer to stay off the track as I am in the early stages of reintroducing intensity while building back after winter surgery; I do not want to strain chasing splits, thus defeating the purpose of the session. Do you guys like any hill workouts or fartleks that can help accomplish this same goal? Thanks!