Washed up D3 runner - Sub 16 5k training ?

This shouldn't to too tough given your background, if you can train consistently for 6-12 months. The first six months getting into a routine of regular decent mileage and learning how to run hard again, the second six months getting really fit. You may break 16 at the end of the first 6 month period, but more likely, you'll run 16:15, take a little break, then come back for another training cycle and run 15:45.

There are no silver bullet workouts or training programs for somebody in your position. You're a talented runner who simply needs to be consistent in building aerobic capacity and then developing the muscular endurance to run hard for 16 minutes.

I'd focus on spending the next six months trying to get your mileage up to 60-70 per week, and doing one workout and one long run each week, along with drills and strides regularly on easy days. For workouts, just cycle through systems. LT week 1, AT week 2 V02 max week 3. Rinse and repeat.

A sample 21 day cycle:

Day 1 (Monday): 8 miles easy

Day 2 (Tuesday): 10 miles easy with drills and strides

Day 3 (Wednesday): 4 mile lactate threshold run (10 miles inc. wu/cd)

Day 4 (Thursday): 8 miles easy

Day 5 (Friday): 10 miles easy with drills and strides

Day 6 (Saturday): 14 miles long run

Day 7 (Sunday): 6-8 miles easy (weekly total mid-upper 60s)

Day 8: 10 miles easy

Day 9: 10 miles easy with drills and strides

Day 10: 7 mile aerobic threshold run (11 miles inc. wu/cd)

Day 11: 8 miles easy

Day 12: 10 miles easy with drills and strides

Day 13: 13 miles long run with 10 x 1 min pickups in last five miles

Day 14: 6-8 miles easy (weekly total upper 60s-70)

Day 15: 10 miles easy

Day 16: 10 miles easy with drills and strides

Day 17: V02 session on the track, 6-8 x 800m (10 miles inc. wu/cd)

Day 18: 8 miles easy

Day 19: 10 miles easy with drills and strides

Day 20: 15 miles long run

Day 21: 6-8 miles easy (weekly total ~70)

After completing this cycle, start again with a structure as in the first week, but change the LT workout slightly to increase volume, intensity, or both. For instance do 5 x 1M cruise intervals instead of a 4M straight tempo. Same thing with the long run. In each subsequent week, hit the same system with your workout, but just add a bit more stimulus. 7M AT run becomes 2 x 4M. 6-8x800m becomes 7x1000m. Etc. With the long runs, focus on running them a little faster each week, of course adjusting for weather conditions such as heat and humidity.

After three or four cycles of these three week cycles, you'll be in really good shape and ready to do a couple of peak 5k workouts (3 x mile, 6x1000m at race pace, etc.) and then try to hit your time. If you don't break 16, take a few weeks of just doing 50-70 mpw easy, then start the whole process again.

Of course, a coach who knows you better as a runner could give you a more specific plan. But with your high talent level, your goal is very achievable - you just need to try to work all relevant energy systems while improving muscular endurance for a bit, and this is one way to do that.

Thanks for the detailed response. That all makes sense.

What are your thoughts on easy run pace?

I have always just listened to my body. i.e i'll pick it up a bit if I feel good (6:30 pace) and go slowly if I feel trashed (8 min pace or just above). My coach in college was a believer in keeping easy runs moderately difficult so pretty much all of them were run just at or below 7 min pace.

For a guy like you with good basic speed, easy run pace will probably vary a lot depending on fatigue levels. When you're just building mileage and not doing much quality, getting down into the mid-low sixes on easy runs is a good thing and will probably happen a lot just naturally. This helps build your aerobic reservoirs. Especially on long runs. If feeling good, make your long run your fastest run of the week in terms of average pace.

BUT when you're recovering from workouts, it's really important to take it slow. Try to keep it above 7 the day after a workout.