# HIIT, LISS & The Numbers



## Contest (Oct 4, 2011)

Hi all,

I've been doing quite a lot of HIIT for a while now but I've recently started to ponder whether the benefits of HIIT are a little over-exaggerated now.

When your goal is to reduce body-fat, aren't the most important things;


To be in a caloric deficit or to create one from performing cardio?

To burn majority of your calories from fat?

To burn as many calories as possible regardless of what intensity you use?


Due to a recent injury, I've began to do more LISS and the numbers have got be intrigued.

Here is what I'm burning according to the stationary bike at my gym.

15 minutes HIIT - 150 Kcal

30 minutes LISS - 200 Kcal

15 minutes HIIT + 15 minutes LISS - 300 Kcal

60 minutes of LISS - 500 Kcal

Even though HIIT has the added benefits of boosting your metabolism and EPOC, surely your not going to burn another 200 calories post HIIT.

In addition to this, from reading articles online, it seems everyone is now on the HIIT bandwagon. LISS cardio gets slated for being archaic and inefficient yet every bodybuilder I know and have ever met only do LISS when it comes to content prep.

Hope some of the more knowledgeable guys here can shed some light on this topic.

@Pscarb

@dtlv

@hackskii


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## dtlv (Jul 24, 2009)

My personal opinion is that the benefits of LISS and HIIT are not that different overall, but that LISS and HIIT each may each have value that the other does not in certain circumstances - LISS being more appropriate for the previously unfit or currently ill or injured; HIIT being better for those looking to maintain maximum muscle mass or anaerobic performance.

In general it's a trade off - LISS burns less overall kcals than HIIT per unit of time, but of the calories it does burn a higher percentage come from bodyfat. HIIT however increases post exercise metabolic rate more than LISS thus adding to the fat burning potential... but as queried in the OP the difference does not actually appear very large at all... I don't remember exact figures but I seem to recall in one study the total 24 hr post exercise difference in metabolism between a 20min HIIT session and a 60 min LISS session averaged at no more than an estimated 30-70kcals.

I think the main thing is to do which ever you are most likely to enjoy and consistently stick to - that trumps any minor physiological or metabolic differences between approaches IMO, because if you aren't consistent or applied to it properly then it doesn't really matter which you chose anyway because you aren't doing it regularly or effectively enough.


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## 3752 (Jan 7, 2005)

LISS works there is no doubt about that I used it for many years but HIIT works better when you look at the overall fat that is burned....

A study carried out in 2006 (on my iPad so do not have the reference but will dig it out) on two groups of women found that the group who did the LISS (40 min) cardio used more calories than the group who performed HIIT (15 min) BUT the group that performed the HIIT burned more fat than the LISS group and at the end of the study the LISS group burnt more calories but did not lower there bodyfat %.....the HIIT group used less calories but they dropped 2% bodyfat......

So although more calories are used performing LISS and that would go towards a normal calorie in/calorie out theory the HIIT cardio burnt more bodyfat and at the end of the day that is the ultimate goal..........


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## Mr_Morocco (May 28, 2011)

Whats LISS?


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## xpower (Jul 28, 2009)

Low Intensity Steady State I belive


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## Big_Al13 (May 2, 2013)

For the reasons @dtlv mentioned, I've started splitting my HIIT and LISS work between the two.

I go straight in to a HIIT session then end with a LISS session. I think it helps overall with the ramp up in fat burning at the end of a training session, but also means that my metabolism is raised for a longer period of time afterwards. From the pictures and progress in my journal it certainly seems to be working.


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## Contest (Oct 4, 2011)

Pscarb said:


> LISS works there is no doubt about that I used it for many years but HIIT works better when you look at the overall fat that is burned....
> 
> A study carried out in 2006 (on my iPad so do not have the reference but will dig it out) on two groups of women found that the group who did the LISS (40 min) cardio used more calories than the group who performed HIIT (15 min) BUT the group that performed the HIIT burned more fat than the LISS group and at the end of the study the LISS group burnt more calories but did not lower there bodyfat %.....the HIIT group used less calories but they dropped 2% bodyfat......
> 
> So although more calories are used performing LISS and that would go towards a normal calorie in/calorie out theory the HIIT cardio burnt more bodyfat and at the end of the day that is the ultimate goal..........


Cheers for your input mate.

A few questions though...


How could 15 minutes of HIIT burn more fat than 40 minutes of LISS? I thought HIIT primarily burned glycogen as a fuel and LISS fat?

I'm assuming this study was carried out on untrained women, but for us guys who weight train frequently, would the results be similar?

Do you still do LISS or have you moved over to HIIT now mate?


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## 3752 (Jan 7, 2005)

Contest said:


> Cheers for your input mate.
> 
> A few questions though...
> 
> ...


It can when you consider EPOC to be fair I think you are underestimating the overall effect this can have



Contest said:


> I'm assuming this study was carried out on untrained women, but for us guys who weight train frequently, would the results be similar?


I am not certain they where untrained but will check but still the results should be similar as the same criteria would be followed



Contest said:


> Do you still do LISS or have you moved over to HIIT now mate?


i moved over to HIIT last year whilst prepping for the NABBA Universe and never looked back, although at the moment due to the type of training I currently do I do not do any cardio....


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## Contest (Oct 4, 2011)

@Pscarb

I'm still really surprised by the fact that EPOC can have such a big effect.

For example, I normally do 15 minutes HIIT + 15 minutes LISS in the evenings which burns roughly 300Kcal. Due to an injury, I did 1 hour LISS tonight instead which burned 480Kcal. As LISS burns calories primarily from fat, would the EPOC from my HIIT session equate, or even surpass my 1 hour LISS session in terms of calories burned and fat loss?

As a side question, how many sessions of HIIT would you do in a week mate? I was doing HIIT everyday (AM + PM) but ended up injury my quads quite severely. I'm now doing 30 minutes of HIIT in the AM after every weights session and HIIT 2x per week in the evenings.


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## simonthepieman (Jun 11, 2012)

I'd recommend both.


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## 3752 (Jan 7, 2005)

Can you quote your reference that LISS burns more energy from fat than carbs please mate I am interested to read it.

One thing I came to understand and that is I do not understand how anyone can do all out balls to the wall HIIT for longer than 20min at a push unless your split was something like 30 sec sprint/2min moderate or rest.......

When I was prepping I did HIIT twice on non training days (not the morning after legs) and once on training days, although I did no cardio on a Sunday which was my refeed days so in total 7 sessions a week, in the off season before I stopped it I was doing it 2-3 times


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## 3752 (Jan 7, 2005)

In a study conducted by Wilson et al. from the University of Tampa, FL, shows when you add in LISS you get a temporary boost in weight loss.

Subjects lost a couple of pounds the first week and after that they lost nothing. This happened because their metabolism completely adjusted to that and that became their new set point to what they had to do just to maintain. LISS with a low calorie diet is terrible for fat loss and could cause muscle loss. During a low calorie diet, LISS cardio is more catabolic (muscle wasting) towards muscle as opposed to HIIT cardio being much more muscle sparing.

In the same study by Wilson et al. it showed:

• LISS caused more muscle loss than HIIT.

• HIIT caused more muscle retention because when doing LISS you're not activating muscles the same way as if you were lifting weights.

• HIIT is another way to overload the muscle.

• A sprinter's body composition to marathon runners, more muscle mass.

• High intensity work activates muscle fibers and therefore is a primer for growth.

• LISS unfortunately can't stimulate muscle fibers the same way.

Reference:

1,2) Wilson, et al. Concurrent Training: A Meta Analysis Examining Interference of Aerobic and Resistance Exercise. University of Tampa, FL. J Strength Conditioning.

A quote from Layne's site on this very subject



> Perhaps even more interesting was that further analysis of the literature on cardio demonstrated that not only was short duration, high intensity cardio better for strength and hypertrophy, it was also superior for fat loss (1).
> 
> I know the broscientists will continue to spout the value of low intensity cardio to maximize the percentage of calories burned from fat, but to quote the researchers "maximizing intensities, which are ideal for fat metabolism during an exercise, may not be ideal for maximizing fat metabolism in the long term.
> 
> ...


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## Contest (Oct 4, 2011)

Pscarb said:


> Can you quote your reference that LISS burns more energy from fat than carbs please mate I am interested to read it.
> 
> One thing I came to understand and that is I do not understand how anyone can do all out balls to the wall HIIT for longer than 20min at a push unless your split was something like 30 sec sprint/2min moderate or rest.......
> 
> When I was prepping I did HIIT twice on non training days (not the morning after legs) and once on training days, although I did no cardio on a Sunday which was my refeed days so in total 7 sessions a week, in the off season before I stopped it I was doing it 2-3 times


I haven't got a particular reference for that statement, it's just something I've read over and over again on the many "HIIT vs LISS" articles on the web. The theory is that fat is the preferred fuel source for low intensity exercise where as glycogen is favored when performing high intensity. From what I've read there seems to be a ratio of what is used as fuel when exercising. When performing LISS, the ratio shifts towards fat and when performing HIIT it shifts towards glycogen. Its not as simple as LISS uses fat 100% or HIIT uses glycogen 100% as some believe like to believe.

What I don't like about these articles thoough is that they always compare the same duration of each form of cardio. If comparing 15 minutes of HIIT vs 15 minutes of LISS, it's pretty evident that HIIT will come out on top. Vice versa if comparing both methods performed over an hour but like you mentioned, performing HIIT for longer than 20 minutes is near enough impossible and most bodybuilders perform LISS from anywhere between 30 to 60 minutes so a better comparison would be 20 minutes of HIIT vs. 60 minutes of LISS using trained athletes.

My HIIT sessions consist of 8 intervals where I use a ratio of 30/60 seconds and I'm destroyed after that. The calories burned during them 8 intervals according to my bike averages at about 150 but when cycling at a low intensity for an hour, I hit 480 tonight.

I guess it boils down to what you want to believe and what is most important to you...


EPOC

Boost in metabolism

Calories in vs. Calories out

The "fat burning zone" myth


I'm a guy infatuated with numbers so am finding it difficult to justify EPOC and the boost in metabolism versus calories in/calories out lol.

I also can't help thinking that wouldn't weight training (if done properly at a high intensity) give you that boost in metabolism and EPOC...

*P.S*

I think its also important to bare in mind that we're assisted athletes so muscle loss isn't as big of a concern for us elite people


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## simonthepieman (Jun 11, 2012)

Pscarb said:


> Can you quote your reference that LISS burns more energy from fat than carbs please mate I am interested to read it.
> 
> One thing I came to understand and that is I do not understand how anyone can do all out balls to the wall HIIT for longer than 20min at a push unless your split was something like 30 sec sprint/2min moderate or rest.......
> 
> When I was prepping I did HIIT twice on non training days (not the morning after legs) and once on training days, although I did no cardio on a Sunday which was my refeed days so in total 7 sessions a week, in the off season before I stopped it I was doing it 2-3 times


I always go by the rule of thumb. Under 15 minutes your going too hard. Over 20 mins too light.

Although the tabata studies imply that a basement of 15 minutes is not required.


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## 3752 (Jan 7, 2005)

Contest said:


> I haven't got a particular reference for that statement, it's just something I've read over and over again on the many "HIIT vs LISS" articles on the web. The theory is that fat is the preferred fuel source for low intensity exercise where as glycogen is favored when performing high intensity. From what I've read there seems to be a ratio of what is used as fuel when exercising. When performing LISS, the ratio shifts towards fat and when performing HIIT it shifts towards glycogen. Its not as simple as LISS uses fat 100% or HIIT uses glycogen 100% as some believe like to believe.
> 
> What I don't like about these articles thoough is that they always compare the same duration of each form of cardio. If comparing 15 minutes of HIIT vs 15 minutes of LISS, it's pretty evident that HIIT will come out on top. Vice versa if comparing both methods performed over an hour but like you mentioned, performing HIIT for longer than 20 minutes is near enough impossible and most bodybuilders perform LISS from anywhere between 30 to 60 minutes so a better comparison would be 20 minutes of HIIT vs. 60 minutes of LISS using trained athletes.
> 
> ...


using steroids does not prevent muscle loss they just make it harder to lose muscle it can and does still happen.....

to be fair every article i have read concerning the comparison between the 2 points to more fat burnt with HIIT than LISS hence why i chose to switch last year and my condition at the Universe was noticeably better than the previous shows in the year where i did the standard LISS cardio.

the problem with LISS is that after a week or two your body adjusts to the cardio thus your metabolism settles (for the want of a better word) where HIIT this does not happen and in fact the metabolism remains high after the cardio has stopped.......LISS does work this cannot be argued but is it the most effective form of cardio? for fat loss, from everything i have read and from my own experiences both pre comp and off season no it is not as Effective as HIIT.......

this study shows that Short Intense Sprints (30s sprint/4m rest) reduced fat mass by 12.4% opposed to 5.4% for Endurance training (30 - 60min runs) Study

here is the abstract of a study (in bold) that compared the two for fat loss, the last paragraph i think answers your question...



> Here's a study done comparing the two:
> 
> Angelo Tremblay, Ph.D., and his colleagues at the Physical Activities Sciences Laboratory, Laval University, Quebec, Canada, challenged the common belief among health professionals that low-intensity, long-duration exercise is the best program for fat loss. They compared the impact of moderate-intensity aerobic exercise and high-intensity aerobics on fat loss. (*Metabolism (1994) Volume 43, pp.814-818*)
> 
> ...


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## TommyFire (Jul 18, 2010)

Personally I do 15-20mins HIIT followed by 30-40mins LISS.


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## Mr JP (Mar 27, 2013)

Anyone seen any of Layne Nortons videos?

I might change to HIIT only after years of running 10k's.


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## Ricky12345 (Jun 13, 2012)

TommyFire said:


> Personally I do 15-20mins HIIT followed by 30-40mins LISS.


X2 but outher way around


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## TommyFire (Jul 18, 2010)

Ricky12345 said:


> X2 but outher way around


Try it the other way round mate.


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## Ricky12345 (Jun 13, 2012)

TommyFire said:


> Try it the other way round mate.


Only issue is mate I count the liss as my walk to the gym witch is around 40 mins then hit up hiit on the treadmill


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## DiscSupps (Oct 26, 2012)

HIIT training is great for an increase in metabolism and the metabolism burning calories for hours after your session. LISS is great work burning fat also but you only burn the calories you use up during the session. Speak to Tom and Scott for further free impartial advice.


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## chelios (Jun 26, 2010)

Seems that HIIT is better after all and I agree for previous progress.

The other question I'd like to throw into this debate is, fasted HIIT for more loss? If it works, or eat first?


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## BurgerKing (Mar 9, 2013)

chelios said:


> Seems that HIIT is better after all and I agree for previous progress.
> 
> The other question I'd like to throw into this debate is, fasted HIIT for more loss? If it works, or eat first?


Interested in people's views on this also


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## tyramhall (Dec 28, 2011)

No idea if fasted training works better for me but i love to wake up early and jump straight on my exercise bike for 20mins HIIT. I do this 3 times a week. After each session i feel like im going to be sick and there is no chance i could do steady state straight afterwards.

For all reports of one is better than the other no doubt there are other reports of the opposite. Everybody is different and its part of the challenge to find out what works best for you.


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## manxjason (Aug 22, 2013)

From what I have read, LISS is best performed in the morning before taking in any calories - this ensures calories burnt are from the bodies supplies, and not food. Once you stop your cardio however so does the calorie burning..

My understanding in HIIT, is that you need the fuel to perform it at 100% sprint, so, around lunch time onwards is the more appropriate time to perform. Ignore what the bike/treadmill says etc in terms of calories. The calories burnt is coming straight from the fuel, and the idea of HIIT is the effect of EPOC / elevated metabolism - so the calorie burning is post workout. It'd be very difficult to calculate how many calories you've actually burnt due to everyones body being different, and the length of elevated metabolism achieved. I'm always hungry much earlier after my post HIIT meal than I am post LISS.

I wouldn't do LISS after HIIT. In fact i'd probably focus on only HIIT one day, and LISS the following to give your muscles time to recover.

then again, i'm fairly new at this but have done quite a bit of reading regarding the topic!

I was previously doing LISS daily and weighed myself daily, with the same diet each day. I found that my weight was going down around 1/4lb each morning following LISS, yet after HITT (only done two sessions so far) the scales have gone down 3/4lb each following morning.

Like I said though, i'm fair new to all this, but, from what i'm seeing so far, it seems to work for me personally...

p.s. First post! Hello all..

Male, 27

5'11"

15st1lb


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## simonthepieman (Jun 11, 2012)

i'm going to leave this here for all to have a look at

http://dynamicduotraining.com/wordpress/15-experts-weigh-in-on-hiit-or-liss-cardio-for-optimal-fat-loss/


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## umairarif (May 24, 2013)

As this is mr olympia season, I hear and watch interviews of guys like phil, jay and wolf, they all tell that they are doing LISS am and pm, If HIIT is better why dont they do HIIT?,


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## nickdutch (Aug 21, 2013)

If my poor memory serves me correctly, when I did biology as part of my year on the Open University, we compared sprinters bodies and marathon runners bodies. The marathon runners were spindly and thin, the sprinters were more muscular looking. So surely it makes more sense for muscle mass to do high intensity if you are looking for good looking sexy muscle and "LISS" for more endurance based muscular development. I understood that there are at least two different types of muscles in the body, the "fast twitch" and another type whose name completely escapes me. Purely from a whole body perspective, doesn't it make sense to stimulate both groups of muscles to help maintain health and vitality? So high intensity stuff to make the fast twitch muscles grow, and something slower and more deliberate, possibly more endurance based for the other type whose name I can't remember?


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## simonthepieman (Jun 11, 2012)

nickdutch said:


> If my poor memory serves me correctly, when I did biology as part of my year on the Open University, we compared sprinters bodies and marathon runners bodies. The marathon runners were spindly and thin, the sprinters were more muscular looking. So surely it makes more sense for muscle mass to do high intensity if you are looking for good looking sexy muscle and "LISS" for more endurance based muscular development. I understood that there are at least two different types of muscles in the body, the "fast twitch" and another type whose name completely escapes me. Purely from a whole body perspective, doesn't it make sense to stimulate both groups of muscles to help maintain health and vitality? So high intensity stuff to make the fast twitch muscles grow, and something slower and more deliberate, possibly more endurance based for the other type whose name I can't remember?


**** me, that's terrible schooling. What year did you do this course?

So if Usian Bolt did long distance training he would like Mo Farrah and vice versa? This is a case of genetic specialization, not training modalities.

I'm not having a go at you as you are just repeating what you were told, but that is really poor information


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## simonthepieman (Jun 11, 2012)

Just to build out from this, there is no black and white answer. And the answer which change on your level of experience, overall fitness and your muscle mass relevant to your genetic limit/potential.

You can't compare a muscular natty guy looking to lose some muffin hips, to a top level heavyweight pro who is in final stages of contest prep. There are so many different variables at play it's like saying what is better for you, vegetables or meat?

HIIT is funny one as much like lifting the effects will reduce as your body and fitness adapts and you keep having to up the intensity and is hard to measure calorie expenditure. However when done correctly it is more 'efficient' calorie burner.

WIth LISS, x number of calories is pretty much the same each session when all variable are managed. That's probably why it's better for Pro's. you can be more precise. It also has recuperative benefits too and raises cortisol less than HIIT. I'm not going into the catobolic debate as 95% of here it's irrelevant to.

The short to what is best, is normally 'a bit of both'. You try to prescribe a 'perfect regime' for the individual, but much like a diet, the 'best' is normally the one you can stick to consistently for the longest period of time (by this I mean how regularly you can do it, rather than the duration of the session).


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## nickdutch (Aug 21, 2013)

@simonthepieman You do raise a very interesting point, how much is genetics and how much is training? I am sure that people who are better at something might gravitate to that one thing, but also if training had no part to play in how you ended up looking, why would there be so much talk about different training regimes and their effects on the human body here on the internet and on this forum?


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## simonthepieman (Jun 11, 2012)

nickdutch said:


> @simonthepieman You do raise a very interesting point, how much is genetics and how much is training? I am sure that people who are better at something might gravitate to that one thing, but also if training had no part to play in how you ended up looking, why would there be so much talk about different training regimes and their effects on the human body here on the internet and on this forum?


To be honest, there far too much talk than action on here 

Training will have a massive impact on your appearance, but peoples specialization, especially at an elite level will be set before them by genetics.

Sadly our parents were lying, you can't become anything you want. However you can become a better version of yourself.


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## finest1 (Jan 2, 2012)

i know im late to get involved in this conversation, but i feel this thread is a good debate regarding LISS and HIIT. i think before embarking on a cardio plan, you need to be honest as to what you want to gain from it. in our fast paced world, everyone wants results in the least amount of time, which is why LISS has taken a hit (no pun intended!) on its effectiveness. this then was replaced by HIIT as the new way to go. you can only go by people's experiences and personal trying. in my case, i tried HIIT 2 years ago as this was going to be the secret formula to getting ripped etc. i wouldn't say i was out of shape, it was only my midsection i let go. yes in the first month (paired with a circuit training type workout) i trimmed up pretty well. but as the months went by it wasn't the case anymore. my body type seems to prefer to burn glycogen and muscle before fat. so what happened to me in the end was, i burnt all my muscle off, and the fat was still there. all i did in the end was look smaller! i also ended making myself ill which took me 2 months to recover.

since then i went the opposite, i've started powerlifting, and really enjoying it. obviously im putting on muscle and fat as my diet is not strictly clean. the next few months im planning to clean up my diet and introduce some sort of cardio. HIIIT will not be a part of it. after researching, ive started LISS this week as i want to preserve as much muscle as i can. one of the reasons why LISS is unpopular is because its time consuming. im not bothered with that as we all have ipods and iphones etc so you can easily pass the time away.

to conclude, you need to try one form for a month, know your body type, and be specific as to what you want to gain.

thanks


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