The January 2016 Running Challenge

runner_girl83 wrote: »

@Stoshew71 I'm going to be a little pain in the *kitten* here and ask if you could kindly explain how interval runs help us run faster on our longer runs? And what distance or time/reps should one run at, at their fastest speed?

And a HUUUUGGGGEE thank you in advance!!!!

You are not being a pain in the *kitten*. I be glad to answer.

So before I answer, need to set some things into context in case we have any third party readers.
We are not talking about run/walk intervals. This is advanced speed work meant for those that already have a good aerobic base and have been running for at least a year consistently.

So I will begin by re-referring to the Jack Daniels video.

According to Jack, the general purpose is designed to maximize aerobic power (how much blood can you deliver to the running muscles and how much of that oxygen being delivered in that blood can convert fuel into energy - or VO2max). And Jack is talking about running these intervals at a pace between 97 to just under 100% of your max HR. Each running interval is between 2-5 minutes max (or if you are measing distance 800-1200 meters) and the rest in between each interval is about equal time.

Then you have what Jack calls Repetition Training or Reps, which is like intervals, but they are done much faster with bigger rest. They improve speed and running eceonomy. The running part is at most 2 minutes (200-400 meters and maybe 800 meters for the more elite). The pace is your current mile race pace.

Then you have Greg McMillan's definition for speed workout: a series of runs between 1-6 minutes done right at your VO2max (your 10-15 minute race pace). They work on a zone that most long distance runners leave dormant. This is very similar to Jack's Interval training. Greg's neuromuscular workout is very simular to Jack's repetition running. Works on the neuromuscular (or brain-to nervous system-to muscle) communication as well as exercising our fast twitch muscles.


So how do these 2 types of workouts specifically help a long distance runner?

Easy running (60% of max effort for long periods) stress our bodies to make our heart stronger, make more hemoglobin, make more capillaries, make more mitochondria, and become more efficient fat burners. Tempo runs make us run right at our aerobic maximum to the level where lactate is at it's maximum steady state.

Interval training in meant for us to train at our VO2max for the maximum amount of time possible.
According to studies, the effects of intermittent training at your VO2max have an improvement to aerobic power. According to these studies, the greatest challenge to our aerobic power occurs when intensity is from 90-100% of VO2max. For example, in these zones, our bodies rely more on myoglobin for oxygen storage and oxygen transport (see Essen study in 1975). Sort of what easy running does for hemoglobin or our red blood cells. Myoglobin in the muscle stores extra oxygen. When oxygen is plentiful (like rest), this protein stores the extra oxygen not being used. When the oxygen supply is very low, like running hard intensity, the myoglobin let's go of the oxygen. In this sense, think of as glycogen in the muscle is to sugar storage, myoglobin is for oxygen storage. Running these intervals help stimulate more myoglobin. The more myoglobin you have, the longer you can hold your breath under water. This benefit would be more applicable to say a shorter distance runner or someone playing field sports (stop & go), but none the less also has some applicability to longer distances.

More importantly, it helps work on muscle fiber recruitment. Specifically we are talking about skeletal muscle, and all 3 fiber types: slow-twitch (type-I), Intermediate fast-twitch (type IIa), and fast-twitch (type IIx). Slow twitch muscles do not give us much power but have lots of endurance. It's the fiber type we depend on the most in the first say 30 minutes at a very slow pace. Fast-twitch or those type 2x fibers, give us that explosive power (stop to fast sprint, or jumping up and down over boxes) but do not have that much endurance. As we run further and further at our slow pace, the type 1 slow twitch muscles start to get tired and we begin to recruit more Type 2a fibers to help us make up the strength to maintain pace. Towards the end of the race, our slow type 2 and intermediate 2a get tired and we have to rely more on our fast-twitch type 2x muscle fibers to help us maintain that same pace. These faster workouts are designed to recruit more of those type 2a and 2x muscle fibers much sooner so they also get a good workout. That way, towards the later stages of the race, those muscles are stronger and we can rely on them more efficiently. Type 2 muscle fibers also operate more anaerobically, while type 1 operates more aerobically. So it makes sense that anaerobic paces make these type 2 muscles fibers more stronger.