Repeats vs. Intervals - What's The Difference?

Buried in a separate thread, a mini-discussion started about pace, distance and recovery times on speedwork. I think I may use these terms as synonyms, and I thik I may be wrong in doing so.

Matt brought up that shorter, faster "repeats" with full recovery serve a different purpose than slightly slower intervals with shorter recoveries. Jim Mul21 brought to the discussion that Daniels draws distinctions between "repetitions" and "intervals."

I thought it may be beneficial to have a discussion about the training purpose and the practices followed, for the benefit of anyone interested.

Is there a difference in your mind? Do you do different types of "speedwork," and why? Does ANYONE know what the "real" definition of running economy is?

Daniels defines repeats and intervals in his terms in order to avoid confusion.

Intervals are 400+, for VO2Max or LT, depending on how one runs it. The recovery time in both is short, not full recovery, so that one constantly accumulates lactate acid, not sure what to push in VO2Max, but the idea is the same.

Repeats train for pure speed, thus one wants full recovery. This is more for short distance or more advanced runners for long distance. I don't do this unless I prepare for 800/1500 track meets.

My simple understanding and I will revisit the concept once I get into sub 2:50.

Running economy is as Matt mentioned the oxygen consumption, the less, the better.

Assume Chris and I have the same VO2Max, which is used by many as an indicator for fitness. That's why Chris can do the same speed workout as Jerry.

Then both run 6:50 pace on treadmill and monitor the oxygen consumption, the number will show Jerry needs less oxygen per body weight, Jerry has better running economy, that's why Jerry races faster.

Again, my simple understanding.

A better example would be an advanced amateur runner like Matt or Dave-O. They probably don't have better VO2Max then Lance Armstrong, but their running economy should be better. That's why they can run faster than Lance.

These days, pretty much everything gets lumped into the term 'intervals'...

However, the term 'interval' actually refers to the time between repeats. The recovery intervals. We don't run intervals, we run repeats with recovery intervals. So, the real definition of 'intervals' is when you are running repeats with a set recovery interval.

When you run 'repeats' your focus in on the distance and the time. You typically run them harder and allow as much recovery as is necessary to complete the entire set of repeats at the target pace.

The problem is that most people just lump it all into 'intervals' which causes some confusion.

Jerry wrote:A better example would be an advanced amateur runner like Matt or Dave-O. They probably don't have better VO2Max then Lance Armstrong, but their running economy should be better. That's why they can run faster than Lance.

So, I get the scientific definition of running economy - it's related to VO2Max, or the maximal volume of oxygen we are capable of using, while running economy is the volume of oxygen used at sub-maximal levels.

But, then building on your example, wouldn't Lance have superior VO2Max AND sub-maximal oxygen use, from cycling, which is largely sub-maximal?

Or, is "running economy" really just running specific, meaning that the brain distinguishes between activities when meting out the oxygen-burning enzymes?

And, what are the best ways to improve it?

You're getting into dealing with specificity in this example. While Lance may in fact have a much higher VO2Max, it's not running specific. He hasn't built the capillary system to the specific muscles that are required to run "fast" for an extended period of time. He'd blow them out of the water on a bike (obviously), but that just doesn't translate to running because of the different muscles being used and the different stresses on the muscles being used even if they are the same ones.

Martin VW wrote:

Jerry wrote:A better example would be an advanced amateur runner like Matt or Dave-O. They probably don't have better VO2Max then Lance Armstrong, but their running economy should be better. That's why they can run faster than Lance.

So, I get the scientific definition of running economy - it's related to VO2Max, or the maximal volume of oxygen we are capable of using, while running economy is the volume of oxygen used at sub-maximal levels.

But, then building on your example, wouldn't Lance have superior VO2Max AND sub-maximal oxygen use, from cycling, which is largely sub-maximal?

Or, is "running economy" really just running specific, meaning that the brain distinguishes between activities when meting out the oxygen-burning enzymes?

And, what are the best ways to improve it?

The best way to improve running economy is running itself. That's why Lance can't beat many amateur runners in running cause he didn't run enough.

Another factor I read is form. My personal opinion is many over emphasize lower body movement, landing, stride length, cadence etc. These are advanced ones in my opinion. I focus on upper body, run relaxed, shoulder down, arm swing etc.

Mr MattM wrote: The problem is that most people just lump it all into 'intervals' which causes some confusion.

Including, as Jim pointed out, Daniels, in that he establishes separate "interval Zones from "Threshold Zones and "Repetition Zones." So, for purposes of furthering the diiscussion, can I suggest that we react to Daniels' way of defining them?

Threshold Pace - Longer (400M - 1 mile) at LT pace with short recovery

Interval - Shorter (400 - 1200 M), faster (5K to slightly sub-5K) with longer recovery

Repetition - Shortest (200 - 400 M), fastest (sub-3K pace) with longest recover

Which do you do, and what are you looking to gain from it? Or, if you do all three, what distinction do you draw between them? How long are the recoveries?

mul21 wrote:You're getting into dealing with specificity in this example. While Lance may in fact have a much higher VO2Max, it's not running specific. He hasn't built the capillary system to the specific muscles that are required to run "fast" for an extended period of time. He'd blow them out of the water on a bike (obviously), but that just doesn't translate to running because of the different muscles being used and the different stresses on the muscles being used even if they are the same ones.

So, you're saying that the muscles used to run are different enough from the muscles used to cycle that he would have to go through a period of running-specific adaptation to impeove his running economy?

I'm not arguing, I'm looking to clarify, at least in my mind. I think this is an area where many runners - including me - don't really think enough about what they're doing, or why.

Me, I just follow the McMillan plan and do what it says. Then get destroyed by the hot temps.

Mr MattM wrote:These days, pretty much everything gets lumped into the term 'intervals'...

However, the term 'interval' actually refers to the time between repeats. The recovery intervals. We don't run intervals, we run repeats with recovery intervals. So, the real definition of 'intervals' is when you are running repeats with a set recovery interval.

When you run 'repeats' your focus in on the distance and the time. You typically run them harder and allow as much recovery as is necessary to complete the entire set of repeats at the target pace.

The problem is that most people just lump it all into 'intervals' which causes some confusion.

For the most part, I agree with Matt's statement. My definition of a repeat is running a distance harder than normal and allowing adequate recovery before repeating the process over again. My definition of an interval would be similar, except the intensity is a little lower and the recovery period is not as long.

I may be wrong or I may be right, but from the discussion I can see how it can get confusing.

Martin VW wrote:
Or, is "running economy" really just running specific, meaning that the brain distinguishes between activities when meting out the oxygen-burning enzymes?

And, what are the best ways to improve it?

Noakes lists the following as impacts to running economy in Lore of Running:

"Vertical motion while running, the ability of the muscles to absorb energy during the shock of landing and transfer it to push-off, biomechanical factors, technique and type of activity, fitness and training, age, fatigue, gender, race, weight of clothing and shoes, and environmental conditions."

As for the best ways to improve it, that's one of the million dollar questions, isn't it? If I think REALLY macro-cycle I can see tremendous benefits from my old RUN MORE mantra, as most runner have more unrealized aerobic capacity potential than other areas, but then I see another layer of performance efficiency that comes from the more subtle areas of form and function at a given pace (or effort level). So, I get my aerobic engine bigger through running volume, but then I need to make sure the timing is perfect so the cylinders fire efficiently. I need to make sure everything is working together in such a manner that when I revv the engine and hit my target speed I'm running smooth.

Running volume helped produce more dense mitochondria so I can produce more intramuscular energy. It helped produce more capillaries so I have greater blood distribution (oxygen delivery and waste removal). The 3 things I can add from here are 1) improved VO2Max; 2) improved LT; 3) improved neuromuscular efficiency.

We know that VO2Max is improved by sustaining a given effort (HR range) for a given period of time, but that it is a capped ceiling. When you get there, you're there. You're not going any higher. Similarly, LT is improved by sustaining a given effort (HR range) for a given period of time, and you can train up to a level which represents a percent of some other ceiling variable (percent MaxHR, percent VO2Max, percent vVO2Max). Elites can sustain efforts closer to their ceiling variables than sub-elites. That leaves neuromuscular effiency. How fast and clean is the neural pathway from the brain to the engaged muscles, and how much contraction am I getting from a given amount of energy? How much ancillary muscle am I engaging during my run?

While all of the other training systems are improved through sub-maximal training efforts, neuromuscular efficiency is the one that seem to require near maximal training effort.

I think that putting it all together results in improved running economy... where we can then do more work using less oxygen. Of course, I could be wrong.

Jerry wrote:

Martin VW wrote:

Jerry wrote:A better example would be an advanced amateur runner like Matt or Dave-O. They probably don't have better VO2Max then Lance Armstrong, but their running economy should be better. That's why they can run faster than Lance.

So, I get the scientific definition of running economy - it's related to VO2Max, or the maximal volume of oxygen we are capable of using, while running economy is the volume of oxygen used at sub-maximal levels.

But, then building on your example, wouldn't Lance have superior VO2Max AND sub-maximal oxygen use, from cycling, which is largely sub-maximal?

Or, is "running economy" really just running specific, meaning that the brain distinguishes between activities when meting out the oxygen-burning enzymes?

And, what are the best ways to improve it?

The best way to improve running economy is running itself. That's why Lance can't beat many amateur runners in running cause he didn't run enough.

Another factor I read is form. My personal opinion is many over emphasize lower body movement, landing, stride length, cadence etc. These are advanced ones in my opinion. I focus on upper body, run relaxed, shoulder down, arm swing etc.

Still another factor in economy is underlying aerobic capacity as provided by improved mitochondrial and capillary density. That isn't developed as much by pure speed work as it is by running below the aerobic threshold and lactate threshold runs. (This is all cribbed from Hadd's Approach to Distance Training, which Dave-O turned me on to a couple of years ago. It's worth reading, if you can wade through all 25 pages.)

Looking at it from Hadd's perspective, the performance of two runners with exact VOMax levels will diverge as the distance increases depending on the level of their aerobic development. The runner with the better conditioned aerobic system will produce less blood lactate and therefore be able to run at a higher intensity for a longer period of time. The runner with the less well conditioned aerobic system may start strong, but he/she will begin to accumulate lactate sooner and won't be able to sustain that level of intensity/speed for the entire race.

How this might translate to Lance is how he was able to run so fast with such a limited specificity of marathon training. His PR of 2:46:43 won't get him into the Olympics, but it's pretty impressive for a guy who was pushing 40 at the time.

Martin VW wrote:

Including, as Jim pointed out, Daniels, in that he establishes separate "interval Zones from "Threshold Zones and "Repetition Zones." So, for purposes of furthering the discussion, can I suggest that we react to Daniels' way of defining them?

Threshold Pace - Longer (400M - 1 mile) at LT pace with short recovery

Interval - Shorter (400 - 1200 M), faster (5K to slightly sub-5K) with longer recovery

Repetition - Shortest (200 - 400 M), fastest (sub-3K pace) with longest recover

Which do you do, and what are you looking to gain from it? Or, if you do all three, what distinction do you draw between them? How long are the recoveries?

Reps are mostly for track guys (read: 2 mile and shorter for high school). My high school coach was a Daniels' disciple and we never touched reps during cross country. We did them toward the end of the track season when he was looking to get us peaked and that last little boost of speed from fast 200s and 400s with a full recovery.

Intervals were our most common workout and we did them up to 1200 meters with usually a 1:1 work to rest ratio since we did static recoveries.

I think the biggest thing lacking from his regimen was the threshold workouts (especially for me, a fast twitch guy back in the day). We seldom did these and I really think it would have been of great benefit for going the 3 mile XC distance, whether we did them as tempo intervals or as a continuous run. And I'd add that I don't think there's much point in going less than a mile at a time for workouts like this because the recovery period is so short anyway.

Martin VW wrote:
So, you're saying that the muscles used to run are different enough from the muscles used to cycle that he would have to go through a period of running-specific adaptation to improve his running economy?

I'm not arguing, I'm looking to clarify, at least in my mind. I think this is an area where many runners - including me - don't really think enough about what they're doing, or why.

Me, I just follow the McMillan plan and do what it says. Then get destroyed by the hot temps.

Yep, I think you can get to a certain point with mixing in biking (a la Tim Miller) but to realize your full potential (or as close as you can get) you need to run pretty much exclusively. There's just a different kind of pounding your muscles and joints take from running and adapting to running that I think (totally my opinion based on experience and some reading) you just can't realize from an "equivalent" activity.

The reason I introduced the concept of running economy is because I think of it as being highly related to neuromuscular efficency. Yes, we have to first develop the cardio foundation through low HR training. But, then we have to learn to use it. And I wonder if low HR training / Run More does that?

I've read about the importance of hill sprints, strides, fartleks and plyometrics (bounding, butt kicks etc) in improving running economy. I wonder if training the brain to utilize the capillary and mitochondial density at higher speeds doesn't improve running economy, similar to hill sprints and strides, in addition to neuromuscular efficiancy?

Wow, my brain hurts from trying to digest all of this; however interesting it is. I think I'll just go Run More and toss in some intervals, repeats and tempo runs. Carry on. Not sure where a 50 yr old woman who has run for over 35 yrs can go at this point anyway. I'm just trying not to lose too much "speed" and the longer intervals with shorter recovery work for me during half and full marathon cycles.

Oh, and I really glad that Martin has joined us! Keep up the discussions.

Michele "1L" Keane wrote:Wow, my brain hurts from trying to digest all of this; however interesting it is. I think I'll just go Run More and toss in some intervals, repeats and tempo runs. Carry on. Not sure where a 50 yr old woman who has run for over 35 yrs can go at this point anyway. I'm just trying not to lose too much "speed" and the longer intervals with shorter recovery work for me during half and full marathon cycles.

Oh, and I really glad that Martin has joined us! Keep up the discussions.

Yeh, I think in the end it'll be helpful to put a nice bow on everything, to demystify it a little.

I know a certain someone that lives in the Wash DC area does full recovery for almost all of his speedwork, while almost everything in McMillan has shorter recoveries. I'd at least to understand what he's getting the benefit of that I'm not.

And the speed sessions put together by the coach of my running club regularly mixes in "repeats" and "intervals" but I've never fully understood the benefit.

And, thanks.

Martin VW wrote:The reason I introduced the concept of running economy is because I think of it as being highly related to neuromuscular efficency. Yes, we have to first develop the cardio foundation through low HR training. But, then we have to learn to use it. And I wonder if low HR training / Run More does that?

I've read about the importance of hill sprints, strides, fartleks and plyometrics (bounding, butt kicks etc) in improving running economy. I wonder if training the brain to utilize the capillary and mitochondial density at higher speeds doesn't improve running economy, similar to hill sprints and strides, in addition to neuromuscular efficiancy?

Yes and Yes.

Martin--That you can run close to a 5 minute mile pretty much whenever you want suggests both high aerobic capacity and good running economy. You probably also have high pain tolerance and strong tendon-muscle fibres. To obtain that sub-3 meant optimizing the brain for the marathon distance and optimizing the slow twitch fibres by running more to develop the mitochondria and getting better marathon running economy. When you ran all of those 18-20 milers, you were on the right track. It just sucks that those miles take up so much time!!

Otherwise, I'm sure you'd still be out there getting ready for Boston '13.

I bet you could still beat Chris' shiny new HM PR given that aerobic capacity and all those recent long runs.

Michele "1L" Keane wrote:Wow, my brain hurts from trying to digest all of this; however interesting it is. I think I'll just go Run More and toss in some intervals, repeats and tempo runs. Carry on.

Oh, and I really glad that Martin has joined us! Keep up the discussions.

Yea, this pretty much sums it up. All this talk is way too technical for me!

Not sure I use either term...If we want to run a track workout the planning discussion with my training partner will pretty much be: Want to run 400's? Sure. How many? 10? ok...How much rest? 200? 400? How about 200? Ok, lets do 10 quarters with 200 jog....

Personally, I like to keep this running stuff simple and not get too concerned about the details. We all know how to drive a car but most of us really don't care how it's made!

Dave Bussard wrote:

Michele "1L" Keane wrote:Wow, my brain hurts from trying to digest all of this; however interesting it is. I think I'll just go Run More and toss in some intervals, repeats and tempo runs. Carry on.

Oh, and I really glad that Martin has joined us! Keep up the discussions.

Yea, this pretty much sums it up. All this talk is way too technical for me!

Not sure I use either term...If we want to run a track workout the planning discussion with my training partner will pretty much be: Want to run 400's? Sure. How many? 10? ok...How much rest? 200? 400? How about 200? Ok, lets do 10 quarters with 200 jog....

Personally, I like to keep this running stuff simple and not get too concerned about the details. We all know how to drive a car but most of us really don't care how it's made!

I am a bit detailed oriented w/running but repeats intervals whatever. Like Dave said I run 6x800's w/ 2min jog.

doesn't matter what you call them, they still hurt

Martin VW wrote:The reason I introduced the concept of running economy is because I think of it as being highly related to neuromuscular efficency. Yes, we have to first develop the cardio foundation through low HR training. But, then we have to learn to use it. And I wonder if low HR training / Run More does that?

No, it doesn't. It doesn't get discussed much, but both of the big gurus of low HR training (Maffetone, Hadd) say higher intensity work is also necessary to keep you from becoming "anaerobically deficient" (Maffetone's term). I saw something Hadd wrote that said the whole purpose of his training - the low HR work and the "initial lactate threshold heart rate" runs - was to build a huge aerobic base strong enough to handle some truly intense speed work when the time was right.

Dave Bussard wrote:

Michele "1L" Keane wrote:Wow, my brain hurts from trying to digest all of this; however interesting it is. I think I'll just go Run More and toss in some intervals, repeats and tempo runs. Carry on.

Oh, and I really glad that Martin has joined us! Keep up the discussions.

Yea, this pretty much sums it up. All this talk is way too technical for me!

Not sure I use either term...If we want to run a track workout the planning discussion with my training partner will pretty much be: Want to run 400's? Sure. How many? 10? ok...How much rest? 200? 400? How about 200? Ok, lets do 10 quarters with 200 jog....

Personally, I like to keep this running stuff simple and not get too concerned about the details. We all know how to drive a car but most of us really don't care how it's made!

BAM!!! I could not agree more!! I'm the same way with all my training keep it simple and there is no need too over think it. One foot in front of the other!

I like to try and understand the training. I run what I run, but I still like to know what's behind it all.

Mr MattM wrote:I like to try and understand the training. I run what I run, but I still like to know what's behind it all.

+1.

I remember seeing articles over the years comparing stocks picked by fund managers versus those picked by throwing darts. In some cases, the dartboard stocks performed better.

That doesn't mean I'm picking stocks using a dartboard.