If you’ve ever read much of what Matt Fitzgerald writes about, you would know he’s in favor of long slow miles. I would have to agree that more miles are better. Hands down. The issue is varying your pace. Many runners get stuck in the rut of running the same pace day after day which is not good. You need to vary your speed and allow for recovery. Matt preaches the 80/20 theory of running 20% hard and 80% easy every 7-10 day cycles. So if you run 400m repeats today, you need to run slow tomorrow and maybe the next day before you then tackle another hard workout. Remember, if your 5k pace is 7:00-7:30 and your marathon pace is 8:45-9:15, then your easy runs can be 9:30 to 10:30 pace. Don’t worry about the distance on these slower runs. I’d aim for an hour of easy running which would get you at 5-6 miles for a recovery run. If you’re struggling through these, you need rest!! Take a day off!! You could also do 45 minutes of spinning or throw in some leg strengthening exercises with this.
Check out Matt’s article.
The best path to long-term improvement for runners is to increase running mileage and overall training volume.
Source: Are You Running Enough Miles? – Competitor.com