Polarized training - How to accumulate the time in the easy zones?

[MattTuck]

So, let's say I'm trying to do some indoor trainer rides low and slow, heart rate in the 130's.

Is there any difference between doing 4-5 days a week @ 1 hour per day compared to 2-3 days per week @ 2 hours per day? I ask because I wonder if that marginal hour has a greater physiological impact than a single hour the next day?

Thanks

[Likes2ridefar]

So, let's say I'm trying to do some indoor trainer rides low and slow, heart rate in the 130's.

Is there any difference between doing 4-5 days a week @ 1 hour per day compared to 2-3 days per week @ 2 hours per day? I ask because I wonder if that marginal hour has a greater physiological impact than a single hour the next day?

Thanks

one hour is brief for pretty much anything IMO. unless it's just basic exercise and if that is the case, have fun. however if you are training for anything I don't really know what one hour a day at low and slow...assuming recovery effort level? will help with. or 2 hours of slow and low a few times a week...

however i think repetition is important for training.

[FastforaSlowGuy]

1 hour daily does not equal 2 hours. But 2 hours on the trainer suuuucks. If you need volume and are relegated to the trainer, a third option is the 3-peat. Ride an hour in the morning, report that evening, then again the next morning. Even short durations - that builds up.

But why are you doing 5 rides a week at Z1 on the trainer? Mix it up sir. Your mind will thank you.


Sent from my iPhone using Tapatalk

[MattTuck]

Yeah, it is a bit weird, I freely admit that. The main reason is because I'm doing a strength training plan 3 days a week, so I don't have as much time as I'd like to devote to riding at the moment, and I don't want to add high intensity riding when I'm trying to increase my lifting. So, it seems much easier to do longer rides on some days and no rides on the days I'm lifting compared to trying to fit in a strength work out and then a ride.

In mid February, I'll be increasing intensity based on the Seiler et al article from 2013. (Basically 4x8 min intervals 2 times per week, with 2-3 additional low intensity sessions.) Though the article isn't specific on length of the low intensity sessions, I am figuring something like an warm up plus an hour. I have the same questions though. If I'm trying to fit in strength training, can I double up a day - 2 hours accumulated low intensity training, and then do strength training on another day without riding.

[Peter P.]

Between the lifting and the 4-5, 1 hour sessions on the trainer per week, I think you'll be a good candidate for burn out.

I'd do 3x1 hour maximum per week at your low and slow level.

Use the trainer sessions just to keep muscle memory and for a light aerobic workout. You'll be fit and fine when it's time to get out on the road again and add some intensity.

[believe]

Yes, there are positive adaptations from riding longer than 1 hr. Ideally, you'll include rides over 90 minutes at Seiler's zone 1 in your training plan. If you have to split your long ride into 2 x 1 hr (morning and night ride) it would be beneficial to limit your carb intake between exercise bouts to induce physiological changes similar to a 2hr ride.

At low exercise intensities most athletes burn carbs at 1-2 g/min. This rate will deplete your glycogen stores in around 90 mins, so you'll want to include rides over 90 mins to induce biological and metabolic changes.

After 90 mins, our slow twitch (ST) fibers are depleted, thus our fast twitch (FT) fibers begin dumping their glycogen in the form of lactate to be converted into fuel. Circulating lactate can go to our liver (Cori cycle) where it is converted to glucose and glycogen, go directly to muscle fibers and be converted to glycogen, go to muscles and be directly metabolized by mitochondria, or go to the heart/other tissues to be used as fuel. Our heart can metabolize a large amount of lactate because it has 4 times more mitochondria than skeletal muscle.

It's important to note, the FT fibers are not being recruited; they're acting as fuel reserves. The breakdown of glycogen in muscle that isn't contracting occurs when our adrenal medulla releases epinephrine, which stimulates the cAMP pathway.

In addition to lactate from FT fibers, our ST fiber energy supply will be maintained with glucose from fat metabolism. At low intensities (zone 1), fatty acid oxidation can contribute up to 50-60% of the energy expenditure.

A quick note about fasting and exercise. When you fast your bodies increases glucagon levels, which acts on the same cAMP pathway mentioned above to cause glycolysis in the liver and dumps glucose into the bloodstream. Skeletal muscles don't have glucagon receptors, so fasting only empties the liver and has no effect on skeletal muscle fuel stores. The only way to empty muscles stores is via exercising.

Another effect of depleting glycogen stores is the increase in enzyme AMPK, which has positive effects on aerobic adaptation. This enzyme signals mitochonria biogeneis and the creation of new blood vessels. Your body becomes more efficient at producing and transporting energy, delivering oxygen to muscles, and removing metabolic waste.

[Peter P.]

Yes, there are positive adaptations from riding longer than 1 hr. Ideally, you'll include rides over 90 minutes at Seiler's zone 1 in your training plan. If you have to split your long ride into 2 x 1 hr (morning and night ride) it would be beneficial to limit your carb intake between exercise bouts to induce physiological changes similar to a 2hr ride.

At low exercise intensities most athletes burn carbs at 1-2 g/min. This rate will deplete your glycogen stores in around 90 mins, so you'll want to include rides over 90 mins to induce biological and metabolic changes.

After 90 mins, our slow twitch (ST) fibers are depleted, thus our fast twitch (FT) fibers begin dumping their glycogen in the form of lactate to be converted into fuel. Circulating lactate can go to our liver (Cori cycle) where it is converted to glucose and glycogen, go directly to muscle fibers and be converted to glycogen, go to muscles and be directly metabolized by mitochondria, or go to the heart/other tissues to be used as fuel. Our heart can metabolize a large amount of lactate because it has 4 times more mitochondria than skeletal muscle.

It's important to note, the FT fibers are not being recruited; they're acting as fuel reserves. The breakdown of glycogen in muscle that isn't contracting occurs when our adrenal medulla releases epinephrine, which stimulates the cAMP pathway.

In addition to lactate from FT fibers, our ST fiber energy supply will be maintained with glucose from fat metabolism. At low intensities (zone 1), fatty acid oxidation can contribute up to 50-60% of the energy expenditure.

A quick note about fasting and exercise. When you fast your bodies increases glucagon levels, which acts on the same cAMP pathway mentioned above to cause glycolysis in the liver and dumps glucose into the bloodstream. Skeletal muscles don't have glucagon receptors, so fasting only empties the liver and has no effect on skeletal muscle fuel stores. The only way to empty muscles stores is via exercising.

Another effect of depleting glycogen stores is the increase in enzyme AMPK, which has positive effects on aerobic adaptation. This enzyme signals mitochonria biogeneis and the creation of new blood vessels. Your body becomes more efficient at producing and transporting energy, delivering oxygen to muscles, and removing metabolic waste.

Rewrite this in English, please.

[Ti Designs]

Rewrite this in English, please.

'Cause it was the best answer I've ever read to that question...

To simplify it, low intensity base mileage needs to go past the glycogen window, which on average is about 90 minutes. Sadly, 90 minutes on the trainer is when most people lapse into a coma.

Limiting carbs between two low intensity sessions is an interesting idea, but I really can't see that working if the gap between rides is more than an hour or so as the glycogen levels will rebound.

A good starting point for this discussion would be what you expect out of base mileage. I have my riders doing 3-4 hour base mileage rides for a number of reasons:

1) Building connective tissue strength. Each pedal stroke is a stress cycle, with this stress the body strengthens it's connective tissue and attachment points. The low intensity work is what prevents injury at higher intensity.

2) Adapting the body to alternate fuel sources - what Believe said

3) Adapting the body to convert fuel without the insulin reaction. This is a bigger deal than most people think, and not just for racers. After the first hour my riders are sending down 250 cal/hour, which means they're still running a deficit, but they are learning to process food during activity. Lots of people never train their body to do this, then they do some long ride and find their blood sugar level crashes when they eat.

4) Work on pedal stroke and efficiency. Like any other activity, practicing at low intensity allows you to form the motor skills needed to keep it efficient at higher intensities. I use average cadence as a gauge of pedaling efficiency, I go to lower gears during the winter but keep my speed the same. I can now sit at 125 RPMs for 30 minutes at the same heart rate as 115 RPMs 6 weeks ago.

5) Learning how to control intensity and workload. When it comes to base mileage, you really need to keep the intensity out of it. Even on hills, I settle my body weight on the pedals and keep it in zone 2 (on a fixed gear with studded tires). Most people focus on the high intensity range when they train - go harder, faster, more effort... I spend months working on the other end, how to limit effort, how to control heart rate, how to recover. People don't get dropped because they don't know how to ride hard, everybody knows how to go hard. People get dropped because going hard isn't sustainable, and they don't know how to recover or limit their efforts.

6) Lull everyone else into a false sense of cycling superiority - I love this part. I'm slow in the winter, I ride a 30 pound fixed gear with studded tires and a 3 pound motorcycle chain. On nice days some guys show up on their perfectly clean (so you know they haven't been out much) race bikes with carbon wheels, and I get my legs ripped off. Somehow they overlook the boat anchor I'm riding and write me off as slow (sometimes they even talk down to me about training).

7) Catch up on all the shows you missed 'cause you were out doing better things.

[ceolwulf]

'Cause it was the best answer I've ever read to that question....


I agree, that was very helpful.

Yours as well, thank you both.

[jr59]

Yes, there are positive adaptations from riding longer than 1 hr. Ideally, you'll include rides over 90 minutes at Seiler's zone 1 in your training plan. If you have to split your long ride into 2 x 1 hr (morning and night ride) it would be beneficial to limit your carb intake between exercise bouts to induce physiological changes similar to a 2hr ride.

At low exercise intensities most athletes burn carbs at 1-2 g/min. This rate will deplete your glycogen stores in around 90 mins, so you'll want to include rides over 90 mins to induce biological and metabolic changes.

After 90 mins, our slow twitch (ST) fibers are depleted, thus our fast twitch (FT) fibers begin dumping their glycogen in the form of lactate to be converted into fuel. Circulating lactate can go to our liver (Cori cycle) where it is converted to glucose and glycogen, go directly to muscle fibers and be converted to glycogen, go to muscles and be directly metabolized by mitochondria, or go to the heart/other tissues to be used as fuel. Our heart can metabolize a large amount of lactate because it has 4 times more mitochondria than skeletal muscle.

It's important to note, the FT fibers are not being recruited; they're acting as fuel reserves. The breakdown of glycogen in muscle that isn't contracting occurs when our adrenal medulla releases epinephrine, which stimulates the cAMP pathway.

In addition to lactate from FT fibers, our ST fiber energy supply will be maintained with glucose from fat metabolism. At low intensities (zone 1), fatty acid oxidation can contribute up to 50-60% of the energy expenditure.

A quick note about fasting and exercise. When you fast your bodies increases glucagon levels, which acts on the same cAMP pathway mentioned above to cause glycolysis in the liver and dumps glucose into the bloodstream. Skeletal muscles don't have glucagon receptors, so fasting only empties the liver and has no effect on skeletal muscle fuel stores. The only way to empty muscles stores is via exercising.

Another effect of depleting glycogen stores is the increase in enzyme AMPK, which has positive effects on aerobic adaptation. This enzyme signals mitochonria biogeneis and the creation of new blood vessels. Your body becomes more efficient at producing and transporting energy, delivering oxygen to muscles, and removing metabolic waste.

Outstanding!!:hello:

[Jgrooms]

'

5) Learning how to control intensity and workload. When it comes to base mileage, you really need to keep the intensity out of it. Even on hills, I settle my body weight on the pedals and keep it in zone 2 (on a fixed gear with studded tires). Most people focus on the high intensity range when they train - go harder, faster, more effort... I spend months working on the other end, how to limit effort, how to control heart rate, how to recover. People don't get dropped because they don't know how to ride hard, everybody knows how to go hard. People get dropped because going hard isn't sustainable, and they don't know how to recover or limit their efforts.

.


This!

Best answer to training advice I've read here. Took me years to figure this out & some never will.

It's important to understand zones, however, what gets lost in that is that its all one system. Done properly, you can go pretty fast in zones 2 & 3.

[teleguy57]

This!

Best answer to training advice I've read here. Took me years to figure this out & some never will.

It's important to understand zones, however, what gets lost in that is that its all one system. Done properly, you can go pretty fast in zones 2 & 3.

This is a great thread. I'm always delighted and humble by the expertise and generosity of folks here.

There are a number of models for zones. What would folks here recommend both for a solid framework and self testing to determine personal zones? I'm not yet in the powermeter world but don't know that I need to do there for my ambitions. HR seems to be still viable, right?

[guido]

4) Work on pedal stroke and efficiency. Like any other activity, practicing at low intensity allows you to form the motor skills needed to keep it efficient at higher intensities. I use average cadence as a gauge of pedaling efficiency, I go to lower gears during the winter but keep my speed the same. I can now sit at 125 RPMs for 30 minutes at the same heart rate as 115 RPMs 6 weeks ago.

5) Learning how to control intensity and workload. When it comes to base mileage, you really need to keep the intensity out of it. Even on hills, I settle my body weight on the pedals and keep it in zone 2 (on a fixed gear with studded tires). Most people focus on the high intensity range when they train - go harder, faster, more effort... I spend months working on the other end, how to limit effort, how to control heart rate, how to recover. People don't get dropped because they don't know how to ride hard, everybody knows how to go hard. People get dropped because going hard isn't sustainable, and they don't know how to recover or limit their efforts.



Are you putting your body weight into the pedals at 125 rpm? Or is that the more quad centric stroke at that pace?

[MattTuck]

Much appreciated believe and Ed. Both very helpful responses.

When it gets warmer, I will happily do 3-4 hour rides outside, at low intensity, and enjoy it! But right now, I'm not going to be doing 3-4 hour rides on the trainer.

I can probably manage a few 2 hour rides per week. That seems reasonable from a time and boredom perspective.

If 90 minutes is the cut off, then it seems every incremental minute over 90 provides the greatest benefit. Based on this, it seems better to do 2 2 hour sessions than four 1 hour sessions, which is exactly what I wanted to know. Thanks

[Ti Designs]

Are you putting your body weight into the pedals at 125 rpm? Or is that the more quad centric stroke at that pace?


Where my center of gravity winds up is based on how much resistance there is at the pedal at the front of the pedal stroke. Climbing, I'm right over the pedals and using my glutes to transfer that weight. Glutes generate the torque to climb, but gravity limits that to about 80 RPMs. Sitting up moves my center of gravity back, so with almost no resistance on the pedals I can still take most of my body weight off my bars. The more upright position also takes angle out of the hips, which makes getting up and over the top of the pedal stroke easier. Using the quads to push forward, my cadence is no longer restricted by gravity.

As a general rule for fixed gear base mileage, going uphill means getting the body weight on the pedals and learning how to use the mass and momentum of your upper body to ride up hills with the least amount of effort. On the flats I sit up a bit and concentrate on using my quads to kick over the top. Going down hill I sit up as much as I can and concentrate on just getting the pedals up and over the top faster. After a while it becomes second nature and you don't have to think about it, it just happens...

[kramnnim]

What is the Seiler plan/article that has been mentioned a few times in this thread?

[MattTuck]

What is the Seiler plan/article that has been mentioned a few times in this thread?

Mark, PM me your email. I'll email it to you.

If you're ok with just the citation, it is: Scand J Med Sci Sports 2013: 23: 74-83

Also, here. (http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0838.2011.01351.x/full)

[ojingoh]

Yes, there are positive adaptations from riding longer than 1 hr....

Post of the (new) year. Thank you for this.

[bluto]

I apologize in advance and I by no means am trying to start some huge debate, but to say there is no performance gain in ones cycling if you don't ride for at last 90 minutes at a time is simply not true. (and I'm referring to racing/performance not casual riders)

[kramnnim]

I apologize in advance and I by no means am trying to start some huge debate, but to say there is no performance gain in ones cycling if you don't ride for at last 90 minutes at a time is simply not true. (and I'm referring to racing/performance not casual riders)

I think "low intensity" is the qualifier for the >90 minute thing...

[MattTuck]

I apologize in advance and I by no means am trying to start some huge debate, but to say there is no performance gain in ones cycling if you don't ride for at last 90 minutes at a time is simply not true. (and I'm referring to racing/performance not casual riders)

I think the argument here is that, at about 90 minutes, your body sends different signals that have an enhanced adaptation effect. So, if you ride 60 minutes for example, and you get some training benefit x for the 61st minute, then the argument above is that if you continue riding until minute 90, the training benefit you get during the 91st minute will be greater than x.

I don't know if it is 2 times x, or 1.05 times x, but there is some enhanced benefit at that level, if I interpret the posts correctly.

[bluto]

I think "low intensity" is the qualifier for the >90 minute thing...

But even with that qualifier I'm still not convinced.

A local ex-pro that raced internationally told me that base rides whether an hour or 5 hours doesn't mean as much as just riding consistently. Another pro that he is coaching even went so far to say that 80% of his riding is done in zone 1,2 and all that matters is the total number at end of the week. Not necessarily how you got there. To get those miles he was sometimes forced to break down his schedule into two one hour increments a day which doesn't fit into the 90:00 model and he's twice as fast as I'd ever dream of being or want to be. :eek:

Every time I try to get scientific and talk about slow twitch, and fast twitch he chuckles and responds "just make sure you're riding consistently."

Best advice I ever got.

YMMV

[FastforaSlowGuy]

But even with that qualifier I'm still not convinced.

A local ex-pro that raced internationally told me that base rides whether an hour or 5 hours doesn't mean as much as just riding consistently. Another pro that he is coaching even went so far to say that 80% of his riding is done in zone 1,2 and all that matters is the total number at end of the week. Not necessarily how you got there. To get those miles he was sometimes forced to break down his schedule into two one hour increments a day which doesn't fit into the 90:00 model and he's twice as fast as I'd ever dream of being or want to be. :eek:

Every time I try to get scientific and talk about slow twitch, and fast twitch he chuckles and responds "just make sure you're riding consistently."

Best advice I ever got.

YMMV

Nobody is saying consistency doesn't matter, but nobody ever got better by riding one duration / one speed all the time. So consistency is critical, but not sufficient.

Best advice I ever got was to NOT pay attention to what the pros do. Of course 80% of their riding is Z1/2 - they ride 30 hours a week. I have a job, so I train 8-10 hrs a week. So their strategy and mine are just different.

Sure, riding 1 hour a day is good stuff. But it's different stuff than riding longer, or riding 1 hour hard, etc. Different physically and psychologically. Gotta mix it up, or you'll be a one-trick pony.

I learned this the hard way back when I did triathlon. When I stepped up from Olympic distances (2.5 hour race) to Half-Iron distance (5 hour race), I suddenly ran into all kinds of weird problems, even though my intensity went down. The body just responds differently and needs time to learn how to keep moving for longer periods of time. I don't know if 90 minutes is the magic number for cycling, but I know that riding 3 hours is different than riding 1 hour on 3 consecutive days.

But yes, all this presumes consistency. As Eddie said: ride lots.

[Chris]

Best advice I ever got was to NOT pay attention to what the pros do. Of course 80% of their riding is Z1/2 - they ride 30 hours a week. I have a job, so I train 8-10 hrs a week. So their strategy and mine are just different.


Seiler seems to imply (well, he actually says it) that for the time-constrained cyclist, the 80/20 approach remains the best approach. You are either going above 90% or below aerobic threshold (77-88% max heart rate). This flies in the face of the guys who say you should be accumulating the most tolerable stress you can such as sweet spot and sub-threshold intervals, especially if you are time-constrained. Seiler's study though looks at elite athletes and I think that is always a little dangerous because of the role that genetics likely plays in filling in the gaps. Lots of elites can just accumulate hours and be fine. Your point then is well made and begs the question of what should a guy like you or I who are on the bike 8-10 hours a week be focusing on?

[wallymann]

4) Work on pedal stroke and efficiency. Like any other activity, practicing at low intensity allows you to form the motor skills needed to keep it efficient at higher intensities. I use average cadence as a gauge of pedaling efficiency, I go to lower gears during the winter but keep my speed the same. I can now sit at 125 RPMs for 30 minutes at the same heart rate as 115 RPMs 6 weeks ago.

great advice across the board.

for this item in particular, it's tough to maintain such extremely high cadences for extended periods! but when you can, it really helps in terms of efficiency and shifting the physiological load to your heart/lungs, saving your legs for when the attacks come thick and fast.

my normal trainer cadence is ~95 all day long for these light workouts and i thought that was pretty respectable. after reading this thread, for grins i tried maintaining 125...no freakin' way! i could maintain a solid ~115 for 5 minutes or so at the end of a workout, but that was it.

more high cadence stuff for me!

[MattTuck]

Seiler seems to imply (well, he actually says it) that for the time-constrained cyclist, the 80/20 approach remains the best approach. You are either going above 90% or below aerobic threshold (77-88% max heart rate). This flies in the face of the guys who say you should be accumulating the most tolerable stress you can such as sweet spot and sub-threshold intervals, especially if you are time-constrained. Seiler's study though looks at elite athletes and I think that is always a little dangerous because of the role that genetics likely plays in filling in the gaps. Lots of elites can just accumulate hours and be fine. Your point then is well made and begs the question of what should a guy like you or I who are on the bike 8-10 hours a week be focusing on?

The Seiler study used 37 recreational cyclists.

[Chris]

The Seiler study used 37 recreational cyclists.

I'm talking about his presentation where he spoke about the elite skiers with whom they worked and their analysis of their training methods. Your point is jogging the memory a bit. What was the duration of that study?

[shovelhd]

This is a great thread. I'm always delighted and humble by the expertise and generosity of folks here.

There are a number of models for zones. What would folks here recommend both for a solid framework and self testing to determine personal zones? I'm not yet in the powermeter world but don't know that I need to do there for my ambitions. HR seems to be still viable, right?

HR is absolutely viable, it just isn't very repeatable until you are well trained and stress throughout your days are pretty steady, plus you are not over trained. This is where RPE comes in to balance what your heart says versus what your body says. Power is the most repeatable and accurate but it is not absolutely necessary. You can definitely set zones with HR. Make sure you are rested before any kind of test and use the same test repeatedly to gauge progress. I use the same course every time. I also don't test much in the winter.

[shovelhd]

Nobody is saying consistency doesn't matter, but nobody ever got better by riding one duration / one speed all the time. So consistency is critical, but not sufficient.

Best advice I ever got was to NOT pay attention to what the pros do. Of course 80% of their riding is Z1/2 - they ride 30 hours a week. I have a job, so I train 8-10 hrs a week. So their strategy and mine are just different.

Sure, riding 1 hour a day is good stuff. But it's different stuff than riding longer, or riding 1 hour hard, etc. Different physically and psychologically. Gotta mix it up, or you'll be a one-trick pony.

I learned this the hard way back when I did triathlon. When I stepped up from Olympic distances (2.5 hour race) to Half-Iron distance (5 hour race), I suddenly ran into all kinds of weird problems, even though my intensity went down. The body just responds differently and needs time to learn how to keep moving for longer periods of time. I don't know if 90 minutes is the magic number for cycling, but I know that riding 3 hours is different than riding 1 hour on 3 consecutive days.

But yes, all this presumes consistency. As Eddie said: ride lots.

Agreed. Unless you are a pro it makes no sense to train like one.

[shovelhd]

To answer the OP's question, if I'm training inside over 2.5 hours I will break it up. Outside not needed.

One mistake power meter users make is using average or normalized power to manage their workouts instead of actively working on staying in zone. That means backing off on the up grades and pedaling on the down grades. Steady pressure. Steady effort. Targeting the average is doing it wrong.

[numbskull]

At low exercise intensities most athletes burn carbs at 1-2 g/min. This rate will deplete your glycogen stores in around 90 mins, so you'll want to include rides over 90 mins to induce biological and metabolic changes.
.

Isn't this workload related?

Wouldn't you deplete glycogen stores faster at higher workloads, hence allowing you to achieve the same biological and metabolic changes earlier than 90 mins?

What is the disadvantage to riding a bit harder to generate glycogen "debt" earlier and thereby shorten workout time?

[MattTuck]

I'm talking about his presentation where he spoke about the elite skiers with whom they worked and their analysis of their training methods. Your point is jogging the memory a bit. What was the duration of that study?

Chris,

the duration of the study I'm referring to had a training intervention length of 7 weeks.

Yes, that presentation mentioned a lot of other studies as well. This one was specific to looking at the best way to include high intensity exercise (low duration, extremely high intensity ranging to longer duration, but lower intensity) Think: 4x4 min max sustainable effort vs. 4 x 16 min max sustainable effort. His results indicated that 4 x 8 minutes (with 2 minutes of recovery) twice a week with 2-3 low intensity sessions had the best improvement across a range of measures.

My original question, as it pertains to this study is whether there is any benefit/difference in how you allocate the low intensity training time. In his study, the 4x8 group trained about 5.7 +/- 1.5 hours per week. So figure the two high intensity sessions are about an hour each between warm up, intervals and a cool down. That leaves a little less than 4 hours per week to do at low intensity.

[Chris]

Thanks for the clarification. I'll look up that study.

[Pastashop]

How does one get 5.7 hours out of 40 minute sessions? (I'm taking 4 x (8+2) = 40 mins for the high intensity session. That's about 9 such sessions. And then one has to do 4 hours of low intensity on top of that?.. Or are we talking about 2 high intensity stretches — 2x(4x(8+2)) — in a single outing?..

[MattTuck]

How does one get 5.7 hours out of 40 minute sessions? (I'm taking 4 x (8+2) = 40 mins for the high intensity session. That's about 9 such sessions. And then one has to do 4 hours of low intensity on top of that?.. Or are we talking about 2 high intensity stretches — 2x(4x(8+2)) — in a single outing?..

First off, the intervention is twice weekly 4x8, with 15 minute warm up, and 2 minute rests. Totals about an hour per session. AND 2-3 low intensity sessions.

See the following table.
http://forums.thepaceline.net/attachment.php?attachmentid=1697903645&stc=1&d=1436961596

Sessions per week minus interval sessions per week is equal to 2.7, so that is how many low intensity sessions, on average. Since average weekly hours was 5.7, we can subtract the 2 hours (the two 1 hour interval sessions) and get 3.7 hours worth of low intensity work.

Doing some dimensional analysis. We can take 3.7 hours / 2.7 sessions to calculate that on average, each low intensity sessions was 1.3 hours.

Does that make sense?