Why Faster Intervals May Not Work for Improving 5K Speed

Having decided to work on running faster for shorter distances this spring and summer, I assumed the best course to develop speed would be to run 400 meter repeats at a pace faster than I was accustomed to- eventually I would adapt and race faster. 

After a couple of workouts I had a hunch this approach wasn't optimal, which was confirmed by an article I found by Pete Pfitzinger in Running Times called Lab Report: Essential Ingredients VII.  The article states "well-trained distance runners should progressively increase training intensity to . . . VO2 max," and elite distance runners should include "progressive increases in the volume of training at or near VO2 max." What this means is that the fitter you already are, the closer to your current VO2 max you need to train to further improve your VO2 max."

So what are the best workouts to spike your VO2 max?  According to Pfitzinger,  "Intervals of two to six minutes typically allow runners to accumulate the most time at 95 to 100 percent of VO2 max"  (think 800- 1600 meters).  What about those fast 400s I was trying to boost speed with?  "Training faster than your VO2 max pace does not provide as great a stimulus to increase your VO2 max because lactate builds up rapidly in your muscles and you cannot sustain that intensity for nearly as long."  In other words, they leave you feeling pretty flat.

I believe high intensity workouts need to simulate 5K racing- the closer you get to that level of intensity the better, and I'm not sure that running intervals considerably faster than that works as well as running them right on the pace you are capable of. 

The last 2 weekends I've done 2-mile time trials in 11:46-47, a pace just slightly beyond my reach for maintaining in a 5K.  Today I ran 3 miles in 18:01 and I felt a dramatic difference.  By running slightly slower the first mile (6:01 instead of 5:53), I still felt strong and was able to maintain for 2 more miles.   Keep this up, and I believe that 6 min pace will soon feel easier to maintain and times will eventually drop.

I am planning a 5K in 4 weeks, my first one is probably a year, so these time trials are helping get back into the racing groove.  Stay tuned.  

For dinner.... sushi 50% off at the Commissary!

2 Miles in 11:47

I ran the same time as last week, however there are signs that I am headed in the right direction. 

1.  I ran 7 miles the day before, whereas last week I did not run.

2.  I felt much better the second mile this time, and ran even splits. 

3.  My cool-down felt good.  I sometimes judge a workout by how I feel AFTER- there are days when I don't even bother with a cool-down jog.  That's a sure sign that I am not strong enough or not recovered enough to handle that particular workout. 

The meal was just your basic burger- prep time less than 10 min.

What Are You Eating?

Workouts are important, but let's not forget about the fuel that enables you to perform them.  Here is my dinner last night.   An assortment of stir fried veggies including a small red potato, wild salmon, and a couple of dumplings.   Prep time 10 min. 

Run Faster With Lighter Shoes

Yesterday my workout called for something hard- like 800 meter repeats, and I was disappointed to see the weather was not going to cooperate- windy, cold, and light rain. 

Fortunately the Super Gym on Camp Humphreys includes a 10 lap per mile track - the tight turns are less than ideal however this was good enough for me to get in the quality I needed for 800s. 

Warm up took longer than usual, and I was having trouble with my right knee, both the result of biking yesterday.  And I was wearing Asics Gel 1140s for added protection (left foot has also been acting up).  The first 3 with 60 seconds recovery were 3:08, 3:05, 3:04. 

Feeling no foot pain I switched to the light-weight Brooks Launch and ran the last 3 in 2:59, 2:59. 2:57- not bad on this track (my guess is the turns cost me at least 1 sec per lap) but I was definitely done after 6.  I felt immediately that I was more efficiently with the lighter shoes, landing more mid-foot than heel.  My opinion is could increase risk for injury if you are not ready for it, which is why I prefer artificial turf for intervals these days.  

Coincidently, check out this recent article in Runner's World- Barefoot vs Running Shoes: Which is More Efficient?   Researchers found that adding 100 grams per shoe increased oxygen cost of treadmill running by 1%.  They also noted that runners with shoes did better than without, however I would like to see that study repeated on a softer surface.  From personal experience, my intervals on artificial turf are always a little faster without shoes. 

Weekend Workouts- Fast, Then Slow

Saturday I ran 2 miles in 11:46 on turf.  I'm not comfortable at all running at this pace, inclining me to believe I need to go back to what I know works- 800 meter repeats and other long intervals.  I plan to get strong on those, then drop down to the 400s to work on speed and leg turnover. 

Sunday I ran 16 miles in 2 hr 22 on a windy, not so nice day.  I had 3-4 sub 8 min miles around 10-14. 

Brooks Mach 13 Spikless Cross Country Running Shoe

Today I ran a 2-mile time trial on turf with an old pair of Brooks Mach 9 Spikeless Cross Country Shoes.   Remove the insole and low and behold that's as close as you can get to a minimalist running shoe.  The Mach 9 feels like it has a slight negative heel drop, encouraging a mid-foot strike.   For $60, I'd like to think this newer Mach 13 version is a good, inexpensive option. 

The Recovery Coach- Matt Dixon

  Recovery, however, shouldn’t be confused with easy. “Recovery is the thing that enables hard training,” Dixon says. If you’re rested and fueled, you can you push yourself to new heights in key workouts and increase fitness.  -The Recovery Approach

This is a good article from Running Times- you can bet that many of us have at one time or another have been carried away by counting weekly miles, or like my weekly sub 7 minute miles. 

Doxon's 4 pillars include endurance, recovery, nutrition, and strength.  You can bet those key workouts he's talking about are brutal.