1k reps vs 400reps to improve 5K

Depends on recovery and a lot of other things, but 2-3k pace for 4800 meters is significantly more stressful and risky than 5k at 5k pace.

Why not both? (not on the same day)

Neither workout is risky unless you are going in hurt.

Whether one is more useful depends your position in the progression, your speed relative to your ability to hold speed.

If the 5000 is new for you, try the 1000m reps.

My guess is you"ll get more out of 3x km 5000 goal pace w/ 200-400m walk + ~5x 400m 2k pace w/ 100m walk.

dsrunner wrote:

Neither workout is risky unless you are going in hurt.

Question for you: how effectively, for running performance progression, would/could racing a 3200m every week be, for those training for the 3-5k?

Jack Daniels Calculator wrote:

dsrunner wrote:

Neither workout is risky unless you are going in hurt.

Question for you: how effectively, for running performance progression, would/could racing a 3200m every week be, for those training for the 3-5k?

Another, related question, would be how about a weekly 12min all-out effort? For elites, that would amount to a weekly >4k all-out race. Does anyone train that way?

Jack Daniels Calculator wrote:

Jack Daniels Calculator wrote:

Question for you: how effectively, for running performance progression, would/could racing a 3200m every week be, for those training for the 3-5k?

Another, related question, would be how about a weekly 12min all-out effort? For elites, that would amount to a weekly >4k all-out race. Does anyone train that way?

And/or how about a weekly 1.5 mile all-out (i.e., VO2Max to the max) effort.

Jack Daniels Calculator wrote:

dsrunner wrote:

Neither workout is risky unless you are going in hurt.

Question for you: how effectively, for running performance progression, would/could racing a 3200m every week be, for those training for the 3-5k?

Very good. Ever seen a college runner improve over the season?

Thanks. I was wondering if guys running the 3-5k over the summer on the Pro European circuit would offer insight.

I never ran on a team in college. Do those guys race that frequently, and if so, what other running (besides easy aerobic mileage) do they do to supplement it?

Looking at it more closely, is it the case that some of these guys are just extending their peak off a huge base, or could they theoretically just continue to improve (taking periodic step-back weeks, if required)?

Jack Daniels Calculator wrote:

Thanks. I was wondering if guys running the 3-5k over the summer on the Pro European circuit would offer insight.

I never ran on a team in college. Do those guys race that frequently, and if so, what other running (besides easy aerobic mileage) do they do to supplement it?

Looking at it more closely, is it the case that some of these guys are just extending their peak off a huge base, or could they theoretically just continue to improve (taking periodic step-back weeks, if required)?

Another analogy is some semi-serious hobby-runners that continue to improve off of running a weekly 5k Park Run, although 5k pace is not quite VO2max pace.