30 second intervals

[FORDGT40]

Hey Solar,

I was just giving as much relevant info from the studies as I could. Glad you think my point is a good one, but most of the evidence [as pointed out by Frenchyge etc] suggests it's not of any use to trained athletes, which makes sense. Very short bouts [<30 sec] dont seem to have any benefit to trained athletes. Might help a couch schlub like me to get started tho!

 

[FORDGT40]

Another topis that thisone blends into that we covered in the degree also, was the principle of "Total Work Done" which is I think what ur getting at. Doing 30/30's at the same power as a 5 minute interval for the same total work period has been hypostulated to provide the same benefit. Im sure there have been studies done by now to prove/disprove this theory, which I'd love to get hold of. The idea is basically trying to get as much benefit for a little input. Even though ur doing as much total work doing 30/30's as 5 minute intervals, it is easier if you have frequent rest breaks, but the theory is that you still elicit similar levels of chemical signal. Using frequent rest breaks also allows you to do more total work, therefore greater benefit. Thats the theory anyway. Anyone know of any good articles on this topic?

 

[dot]

Well, as is typical for a thread that revolves for nearly 3 months, the discussion is losing the relevant comments that were made when it was fresh on people's minds. In summary, the OP asked about whether sets of very short interval were more effective than typical interval durations at improving VO2max. In the first 15 posts are links to over half a dozen studies relating to that issue if people are interested in the possible answers to that question.

Out of curiosity I'd like to ask you what particular physiological changes you want to achieve with such a type of VO2max training and on what scientific(-like) basis it's founded? Which component (or components) gives contribution to growing number of VO2max?

 

[frenchyge]

Out of curiosity I'd like to ask you what particular physiological changes you want to achieve with such a type of VO2max training and on what scientific(-like) basis it's founded? Which component (or components) gives contribution to growing number of VO2max?

Depends on the state of training within the individual. This article: http://home.hia.no/~stephens/vo2max.htm suggests that O2 delivery is the limiting factor of VO2max in well-trained athletes, which would indicate to me that increased muscle capillarization, cardiac stroke volume, and plasma volume would have the greatest effect on raising the VO2max number. In less-trained athletes, O2 extraction and utilization by the muscles themselves may be the limiting factor, which might point back to mitochondrial content in the muscle fibers.

 

[WarrenG]

Another topis that thisone blends into that we covered in the degree also, was the principle of "Total Work Done" which is I think what ur getting at. Doing 30/30's at the same power as a 5 minute interval for the same total work period has been hypostulated to provide the same benefit. Im sure there have been studies done by now to prove/disprove this theory, which I'd love to get hold of. The idea is basically trying to get as much benefit for a little input. Even though ur doing as much total work doing 30/30's as 5 minute intervals, it is easier if you have frequent rest breaks, but the theory is that you still elicit similar levels of chemical signal. Using frequent rest breaks also allows you to do more total work, therefore greater benefit. Thats the theory anyway. Anyone know of any good articles on this topic?

I think I said most of this before but I'll try again. For improving VO2max the 30/30's should be done at power above what you'd use for a 5' interval-can be substantially above.

When you look at group studies concerning 30/30 or 3-5' for VO2max you see the average changes for the whole group. According to my coach's experience, sprinter types tend to gain more with the 30/30 format and riders more inclined towards endurance tend to do better with the longer format intervals. This difference in response won't be reflected in the studies y'all have mentioned so far.

IME, I really like the 30/30's and right before peak they evolve to 40/20. Power targets are increased to way above VO2max power-around 100-150+ watts above VO2max power for 40/20 and around 200+ watts for 30/30. I can tell you I could never get close to that for 3-5' for more than one rep without a long rest between reps. I think sprinter types tend to accumulate more lacate and the little rests allow some recovery, so in the end, they can accomplish more total, relevant work with the short intervals than by trying to do longer reps.

Also, the 30/30's require many little accelerations which create some immediate oxygen debt periods for each of all those intervals. There is a moderate neuromuscular component too for all these accelerations. For a criterium rider, these are a useful part of the training.

This year we increased the difficulty of my SFR (low cadence, ~threshold power on hill ) training and it's improved my accelerations so much that we increased the power targets for the 30/30's after a few weeks, i.e. the accelerations were easier so the rest of the interval was less taxing than at similar power at a similar time last year.

Why not experiment for yourselves to see which one works best for you? And consider, are you trying to get better at riding/racing or better at a VO2max test?

 

[dot]

Depends on the state of training within the individual. This article: http://home.hia.no/~stephens/vo2max.htm suggests that O2 delivery is the limiting factor of VO2max in well-trained athletes, which would indicate to me that increased muscle capillarization, cardiac stroke volume, and plasma volume would have the greatest effect on raising the VO2max number. In less-trained athletes, O2 extraction and utilization by the muscles themselves may be the limiting factor, which might point back to mitochondrial content in the muscle fibers.

Ok then. As long as I understand long series of the 30 intervals with equal rest should elicit very strong acidosis in working muscle which leads to extremely high concentration of free H+ ions which consequently leads to destruction of mitochondrial structures. So I cannot consider these intervals "healthy" for improving muscular endurance. As far as I know, capillarization development is tightly assosiated with the development of oxidative capacities therefore such taxing workouts can't help it either. That's why I prefer 30 second intervals with longer rest, 2.5-3 min between tries or short sets (3-4) of 30/30 intervals which do not increase acidosis to extreme level. As you proceed with oxidative capacity development throughout the season lactic acid levels at the same power level decrease because highly developed oxidative enzymes firstly inhibit glycolitic activity (a well-known proverb says endurance kills speed) and secondly produce more energy via oxidation process. And eventually your power increases.

As for heart strength, I believe that best form of building heart strength not stroke volume is 80-90 sec intervals with HR steady at 90-92% of MHR with approrpiate rest about 3-4 minutes between tries. And they can only be performed in the second half of the season when such a long interval does not elicit high level of acidosis which might hurt muscle oxidative capacity.

Also it should be mentioned that a type of intervals should be selected for each individual by taking into account his muscle composition. E.g. a pure climber just cannot achieve dangerous levels of acidosis because of lack of glycolitic fibers so he can do 30/30 intervals as long as he can perform it without noticeable fatigue. But pure sprinters can hurt themselves easily (oops, not for WarrenG, he is track sprinter and they have to work fine for him).

 

[FORDGT40]

To answer very basically one of your questions dot, consider a really bad cut on your skin. Whenit is finally repaired, the skin is less flexible, more taught, basically its tougher right? thats because you have damaged an area of tissue, which your body responds to by laying down more collagen which makes it stronger. Same thing with damaging mitochondrial structures. If you damage them, your body responds my creating more [within limits] to ensure the same thing doesnt happen again [but it will]. Same thing with oxidative enzymes. In one of my other posts on this page, i refer to an article that found improved oxidative capacity after interval training of this type, Angiogenesis also occurs when O2 delivery is insufficient.

The best way to increase LV diameter is endurance work, not interval training. The main benefit from interval Training is derived from improved buffering, increased mitochondrial density, and other intramuscular adaptations. I wonder exactly what you mean by heart strength though? It has a place but the context needs to be defined. Increasing contractility will increase the LV ejection volume and fraction which improves output, but at greater energy cost, and without increasing LV volume [this is how heart transplant patients adapt as they are limited to ~100bpm 24/7]. Long-term Endurance training also increases heart mass by increasing LVES volume while the wall thickness generally stays the same.

You are quite correct in saying that the duration of intervals and rest periods should be tailored to the individual based on their requirements.

 

[acoggan]

Another topis that thisone blends into that we covered in the degree also, was the principle of "Total Work Done" which is I think what ur getting at. Doing 30/30's at the same power as a 5 minute interval for the same total work period has been hypostulated to provide the same benefit. Im sure there have been studies done by now to prove/disprove this theory, which I'd love to get hold of.

None of which I am aware.

Andrew R. Coggan, Ph.D., FACSM

 

[SolarEnergy]

Hey Solar,

I was just giving as much relevant info from the studies as I could. Glad you think my point is a good one, but most of the evidence [as pointed out by Frenchyge etc] suggests it's not of any use to trained athletes, which makes sense. Very short bouts [<30 sec] dont seem to have any benefit to trained athletes. Might help a couch schlub like me to get started tho!

Yep I agree.

Although I stay open minded, I haven't read any interesting data on the subject yet.

The two studies you quote, are irrelevent to me.

The one on short intervals, use untrained subject.

The other one, use 5 (or 4?) minute intervals, followed by only 1 min rest. That is L4 workout, maybe lower limit L5.

I stay open minded, but look forward to read something meaningful.

 

[frenchyge]

Ok then. As long as I understand long series of the 30 intervals with equal rest should elicit very strong acidosis in working muscle which leads to extremely high concentration of free H+ ions..... <snip>

I don't believe this is the case. The physiological responses involved are somewhat slow (half life ~30 seconds), which means that there isn't time for acidosis to rise to high levels before the rider is resting again. Between the slow buildup during the 30 sec 'on' period and the slow decline during the 30 sec 'off' period, the lactate response for 30/30 intervals should resemble that of a continuous effort at the average power between the 'on' and 'off' levels.

 

[acoggan]

IME, I really like the 30/30's and right before peak they evolve to 40/20. Power targets are increased to way above VO2max power-around 100-150+ watts above VO2max power for 40/20 and around 200+ watts for 30/30. I can tell you I could never get close to that for 3-5' for more than one rep without a long rest between reps.

Can you provide actual numbers for your power during the on and off periods, vs. what you might maintain during a 3-5 min interval? From what you state above it's hard to figure out whether or not your VO2 would be as high or higher during the 30/30 or 40/20 vs. a continuous effort.

 

[acoggan]

mitochondrial structures. If you damage them, your body responds my creating more

The best way to increase LV diameter is endurance work, not interval training.

I am unaware of any scientific data to support either of the above statements (at least in the context of the effects of endurance exercise training).

 

[acoggan]

I don't believe this is the case. The physiological responses involved are somewhat slow (half life ~30 seconds), which means that there isn't time for acidosis to rise to high levels before the rider is resting again. Between the slow buildup during the 30 sec 'on' period and the slow decline during the 30 sec 'off' period, the lactate response for 30/30 intervals should resemble that of a continuous effort at the average power between the 'on' and 'off' levels.

While many physiological responses respond to changes in exercise intensity with a half-life of ~30 s, blood lactate is not one of them. Thus, while the pattern of blood lactate accumulation during 30/30 intervals will be considerably different than what would be observed during continuous exercise at the "on" power, it won't necessarily be the same as that found during continuous exercise at the same average power, either.

In any case, it is the events within exercising muscle that are of primary interest, and those will depend very heavily upon precisely how hard you go during the "on" periods. In the absence of that information (including the distribution of power within that 30 s period), it's really hard to predict what the physiological responses, and hence adaptations, to 30 s on/off intervals will be.

 

[frenchyge]

While many physiological responses respond to changes in exercise intensity with a half-life of ~30 s, blood lactate is not one of them. Thus, while the pattern of blood lactate accumulation during 30/30 intervals will be considerably different than what would be observed during continuous exercise at the "on" power, it won't necessarily be the same as that found during continuous exercise at the same average power, either.

I understand that blood lactate will not respond as quickly as the ~30sec half-life would indicate, but as you mention below we're not necessarily concerned with what *blood* lactate is doing. It was the detrimental effects of proton accumulation/pH drop within the cells that seemed to be a concern for the previous poster. Wouldn't those intra-cellular effects be related to the ~30sec half-lives that you measured during your research?

In any case, it is the events within exercising muscle that are of primary interest, and those will depend very heavily upon precisely how hard you go during the "on" periods. In the absence of that information (including the distribution of power within that 30 s period), it's really hard to predict what the physiological responses, and hence adaptations, to 30 s on/off intervals will be.

These intra-cellular responses are what I was assuming would be occuring with a ~30sec half-life. Assuming the buildup and decay half-lives were similar, wouldn't the overall response to a series of several 30/30 reps resemble the response from a continuous effort at the average power between the on/off cycles? If I'm reading you correctly, your Normalized Power writings would seem to indicate that that is the case. Phew, that's a lot of "ass-u-me-ing" for one post.

 

[fta]

recently i've seen some references to research suggesting that rides incorporating numerous 30 second intervals "all out" may illicit faster gains in VO2 max than other forms of training.

does anyone do these and if so how - how many intervals and how long is the session?

alternatively - i know ive seen references to this on the forums before - but cannot find, can anyone remember and provide a link?

robkit
re 30 secs intervals
two formats
First flatout: 30 secs eyeballs then 4.5 min recovery look to continue until the effort is tailing off. Long term aim is 12 ie an hours work. Ideal for TTers and trackies, wont do any one any harm. Leave till april/may and use for peaking for an event, twice aweek.
Inn winter use 30 secs on and 30 secs off for an hour at your 25 mile tt time/pace. Might be best done on turbo. Look up back issues of peak performance for further info. ref is a French physiologist.
FTA

 

[dot]

I don't believe this is the case. The physiological responses involved are somewhat slow (half life ~30 seconds), which means that there isn't time for acidosis to rise to high levels before the rider is resting again. Between the slow buildup during the 30 sec 'on' period and the slow decline during the 30 sec 'off' period, the lactate response for 30/30 intervals should resemble that of a continuous effort at the average power between the 'on' and 'off' levels.

Try making almost all out effort for 30 seconds, not like all-out sprint but somewhat near to it. Do you feel pain or burn in legs? That's severe acidosis.

 

[frenchyge]

Try making almost all out effort for 30 seconds, not like all-out sprint but somewhat near to it. Do you feel pain or burn in legs? That's severe acidosis.

I do a few 30sec high-cadence spin-ups to over 400w as part of my pre-ride warm-up routine to get the buffering agents flowing, and no, they don't cause any pain or burning in my legs. It's barely enough to make my legs warm with increased blood-flow.

I have no doubt that several minutes of on-off would make my legs feel tired, but then, so do my 4-5 minute VO2max intervals. Even then, the burning sensation is low-to-moderate.

 

[WarrenG]

Ok then. As long as I understand long series of the 30 intervals with equal rest should elicit very strong acidosis in working muscle which leads to extremely high concentration of free H+ ions which consequently leads to destruction of mitochondrial structures.

I can tell you from experience that there is not strong acidosis when I do these intervals. Lots of heavy breathing and some fatigue in the last few intervals but virtually no pain from low ph.

As for your comment about destruction of mitochondrial structures, I've discussed this a few times with my coach and he says there isn't strong evidence available to support this, but it _might_ be possible. He says that a bigger concern would be the enzymes being produced during aerobic vs. anaerobic training and that these may be the concern to at least keep an eye on.

Since it is so early in the season we have kind of a limit to the intensity of near 150% of power at 4mmo/l, and HR shouldn't go much above the rate near 4mmol/l. We also look at how quickly HR is recovering between intervals to ensure that there isn't overdue stress for this early in the season.

FWIW, many racers and pros choose to begin racing in January and February (some high intensity and low ph) and can still show significant improvement for their aerobic ability.

That's why I prefer 30 second intervals with longer rest, 2.5-3 min between tries or short sets (3-4) of 30/30 intervals

These wouldn't elicit an environment similar to that around VO2max intensity so I think you're training something else-I'm not sure what.

Also it should be mentioned that a type of intervals should be selected for each individual by taking into account his muscle composition. E.g. a pure climber just cannot achieve dangerous levels of acidosis because of lack of glycolitic fibers so he can do 30/30 intervals as long as he can perform it without noticeable fatigue. But pure sprinters can hurt themselves easily (oops, not for WarrenG, he is track sprinter and they have to work fine for him).

We are cautious with them (see above) until later in the season.

 

[WarrenG]

Can you provide actual numbers for your power during the on and off periods, vs. what you might maintain during a 3-5 min interval? From what you state above it's hard to figure out whether or not your VO2 would be as high or higher during the 30/30 or 40/20 vs. a continuous effort.

I haven't done any 3-5 minute intervals in training that were near VO2max.

Right now, power is limited to 440-480w (~150% of power @ 4mmol/l) during the on. During the off it's just moving my legs. We're still adding to the total time. Yesterday it was 3 sets of 7' with 4' rest between sets. Once that progression is done we'll add to the power during the on portions. I could handle higher power now but my planned peak is still 6 months away.

 

[acoggan]

I understand that blood lactate will not respond as quickly as the ~30sec half-life would indicate, but as you mention below we're not necessarily concerned with what *blood* lactate is doing. It was the detrimental effects of proton accumulation/pH drop within the cells that seemed to be a concern for the previous poster. Wouldn't those intra-cellular effects be related to the ~30sec half-lives that you measured during your research?

They would, but you were talking about blood lactate kinetics (which aren't identical to the kinetics of blood [H+], BTW).

These intra-cellular responses are what I was assuming would be occuring with a ~30sec half-life. Assuming the buildup and decay half-lives were similar, wouldn't the overall response to a series of several 30/30 reps resemble the response from a continuous effort at the average power between the on/off cycles? If I'm reading you correctly, your Normalized Power writings would seem to indicate that that is the case. Phew, that's a lot of "ass-u-me-ing" for one post.

You're reading everything perfectly correctly, but you're missing a crucial point: if the half-life is ~30 s and you do intervals that are 30 s on, 30 s off, then you'll see significant variation in cellular energetics, etc., across time. Only when the work and rest periods are much shorter than the half-life (i.e., 15 s or less) does things become almost completely "blurred" together.