My problem with speed is less an issue of legs and more an issue of lungs. When running quicker than an easy/aerobic pace my breathing becomes labored (with wheezing); and my heart rate climbs rapidly. I think the return of colder weather has caused my asthma symptoms to return.
I started running 5 years ago to improve my health and avoid being dependant on long-term medication. At the time I was taking blood pressure, cholestoral and several asthma medicatations. Running let me overcome the need for those medications; and my asthma symptoms (which had been a part of daily activities; like simply walking up stairs) diminished to the point where they appeared only on fast runs.
After 8 months of running without AdVair (or any medication) I thought I had overcome it. Now it looks like I need to renew that perscription. Ironic; I started running to avoid taking medication, now I need it to run better!
Until I'm back on AdVair I'll change venues for the faster workouts. On my treadmill (in warm, moist air) the symptoms are greatly diminished. I'm worse in cold, dry air and during the height of the pollen season (probably related to alergies).