All About Time: Ideas for Manipulating Rest Periods in Strength Training for Force Potential (not Bodybuilding)

Posted on 20 May 2011 22:17

Most people know two things about interset rest periods for strength training: you can rest shorter or you can rest longer. If you rest shorter you are training for endurance and if you rest longer you are training for strength.

That is a fairly simplistic way of viewing it and yet that is just about the level of sophistication that most trainees bring to thinking about rest periods. But wait! It makes sense on some level. To keep things simple, for our purposes we can define strength and endurance in the following way:

  • Strength is the ability to produce force by muscular effort.
  • Endurance is the ability to sustain that force production a given period of time, whether holding a position or performing many repetitions.

Variously referring to muscular endurance, strength endurance, or muscular strength endurance, other definitions which are a bit less precise are often proposed for muscular endurance. Such as the ability to perform work over a long period of time or the ability to sustain muscular contractions over time. These definitions are great for a general population. They would fit, for instance, the ability of a cashier in a grocery store to continually pick up products, scan them, etc. But this is just doing work so does not fit our needs for strength development. It's easy to understand why…the weight does not get any lighter as you lift it up and down. You have to exert the same amount of force to lift it on the last rep as on the first rep. So we are concerned with sustaining force production.

If you think that a key to developing muscular endurance is doing more work in less time then it is logical to work towards less rest. If you think strength is about maintaining muscular force output over time then it makes sense to rest longer and therefore be able to exert that same level of force for more reps (i.e. more work).

But of course, in reality, it takes a little bit of everything, along the way, to keep getting stronger. So, if your only conception of rest is 'shorter for endurance' and 'longer for strength' how do you know how to use rest periods? The answer most of the time is "I'm building mass right now so I rest shorter" and then "I'm emphasizing strength right now so I rest longer". What this really translates to is that you are on the fence! As I've tried to make abundantly clear in most all of my writings, strength training for maximal strength is always about developing absolute force potential. Or, in plain English, it is always about getting stronger!

A bunch of time spent "emphasizing" mass means you are sacrificing force potential. You have to play catch up and "turn" that mass into force. Seems silly to even type out to me but that is how people think about it much of the time…as if it is not crazy to work your ass off to build a muscle that you then have to teach how to work! How you think about rest periods governs how you use them. There are other ways to think about rest periods and instead of using rest periods you can learn to "take advantage of them".

Rest between sets is the same as rest in general, to some extent. It is about recovery. Longer rest periods mean more time to recover and more time to recover means maintaining more strength over the course of a session. If we take longer rest periods and shorten them over time, by whatever means, we can learn to maintain a certain force with less rest. In other words, we can "recover" from it quicker. But the downside to that is the point of diminishing returns. There comes a time when you are no longer doing strength training but endurance work..thus the definitions given above.

Let me give a very straight-forward, but extreme, example. If I were to do 400X5x5 reps using 5 minute rest periods I could try to increase my reps and even increase my sets in order to build up endurance. Alternatively, I could do none of that and instead decrease my rest periods over time. I could try to shorten the rest periods until I got to the point I could do the same sets except only using 2.5-minute rest, or less, between sets. This would increase the ability of my muscles to recover quickly and thus increase muscular endurance. After all that effort, however, what have I accomplished? I can "endure" the work better but does this translate to a higher 1RM? Not really. I haven't increased my force potential by very much, if at all. I've increased my endurance.

It should be a given that you cannot increase strength a great deal without increasing the load but many trainees seem to think that an increase in muscular endurance should correspond to a predictable increase in their 1RM. It doesn't.

The above scenario doesn't seem to be worth the trouble and yet I told you before that it does take a little bit of everything. Meaning that along the way you will be using all sorts of different rest periods.

Obviously, for your secondary or assistance exercises, you will use shorter rest periods than for your main lifts. Both for time management and relating to the goal of those exercises. Usually, for me that means "gathering volume" (which does mean mass), staying balanced, and putting forth beneficial work towards helping your main lift. But beyond that, you will use different amounts of rest even for your big lifts. Since the scenario above failed and we ended up just spinning our wheels in terms of absolute strength, what do we do?

It's Not Endurance But Work Tolerance

At first glance that seems like the same thing. But not quite. Tolerance simply has a much broader meaning than endurance. Endurance is a part of tolerance but not the whole meaning. Let's say you can run three miles in a go. This speaks to your level of endurance for running. But let's say you get terrible cramps afterward. This speaks to your level of tolerance. So, even though you can endure the running you don't have a lot of capacity to accept its consequences. You might say, "all things being equal I could run three miles" but all things are not equal and you probably won't be running much until your tolerance for running improves and you are not affected by it by having terrible muscle cramps.

Work tolerance, as opposed to just endurance, means that we can maintain certain levels of work without breaking down. Without sustaining injury for instance. But it also entails our ability to withstand it psychologically. We call that "fortitude". Just like endurance, tolerance is something we have to build up. We can do that by manipulating rest, and thus recovery.

A strength trainee has very little need to be able to lift heavy weights with one minute rest in between. You want to lift the heaviest weight possible. You like to lift things up and put them down. Yeah, yeah. So do I. In order to lift very heavy things, though, you have to be able to lift very heavy things a lot. How's that for technical?

Are you not feeling me? Well, maybe you've been excited when your favorite powerlifter managed to pull some super human weight. You see a guy lift 800 pounds and you go wow, I wish I could do that. What you don't think about is how many times he has lifted, say, 730 to 780 pounds and just how much work that is. To get to that 800 he had to be able to tolerate a lot of heavy pulling without pulling something! I know "corrective exercise" is big right now but if you think rotator cuff exercises are going to get you to an 800 pound deadlift, well you really don't know what work is.

Now if we just wanted to endure we could lift very very light weights for many many reps. This would be classically what we think of as endurance. One might relate this to a marathon. The intensity is very very low and such levels of aerobic work can be sustained for unbelievably long periods of time, especially if fuel is taken on board. But a middle distance runner, or a swimmer, might want to increase his capacity to run near top speed for longer periods of time. This has to do with tolerance.

Example: Lactic Acid Tolerance Training

Lactic acid threshold training was a big thing for a while. The idea was to increase the period of time you could work before reaching the "threshold" upon which time you cannot work for very much longer because of the build-up of lactic acid. But then a lot of physiologists explained that there was no real "threshold" and everyone got confused and went back to twiddling their thumbs at Pubmed. For a while though "lactic acid threshold" training was big from bodybuilding to powerlifting.

But lactic acid tolerance training is a real thing (sometimes called lactate tolerance). It is mentioned in Periodization Training for Sports by Tudor Bompa in the following passage:

Lactic acid tolerance training increases athletes' ability to tolerate lactic acid buildup…Very high levels of lactic acid can result from high-intensity reps of 40 to 50 seconds. Lactic acid tolerance increases as a result of skeletal muscles' removal of lactic acid from the bloodstream. [According to studies] lactate transporters increase in number as a function of high-intensity training…The ability to clear lactic acid from the bloodstream and transport it to slow-twitch fibers for energy usage is an adaptive response that delays fatigue and inevitably improves performance." - Bompa1

How do you "delay fatigue"? You manipulate rest and recovery, just like I've been saying. To delay fatigue you manipulate fatigue. You work with it, not against it. The same thing is needed to train for maximal strength but we really do not need to worry about the physiological details to know how to do it.

Bompa goes on to talk about the ability of an athlete to tolerate the pain of acidosis. He means to be able to tolerate "the burn" and that athletes who can tolerate this better can perform longer. Tolerance, not just endurance, see?

Consolidation is about increasing work tolerance for a certain weight range. But it really makes up a large part of what we are doing when strength training.

Working Under Fatigue

We don't need endurance but one thing we do need is the ability to work under conditions of fatigue while still maintaining a high force output. I don't just mean lift a weight up and put it down a bunch of times really fast. I mean do it with a modicum of control and without technical (and dangerous) failure. There is a very simple way to think about it. If you can pull pretty well in the 760 to 780 range while compromised then you will have a much better chance of doing that 800 while NOT compromised.

A great deal of what I do then is to have trainees learn to manipulate fatigue. That is a bit different than the seat-of-the-pants method that has been given the flowery name "Planned Over-reaching". Planned over-reaching is a fancy way of saying "get real tired, rest, and get stronger, I hope." We don't want to just get tired, we want to get tired with style.

Enter the Cluster

You've probably heard of clusters. All sorts of fancy theories are given about how clusters work. Most having to do with the nervous system and "hypoxia" and other jargon of the sort. But clusters, at their basic level, are just a way of manipulating fatigue and recovery. The goal is to lift a certain weight more times than you would normally lift it in one straight set. Clusters involve inserting little mini-rest periods between single reps of a multi-rep set. This way you recover just a little but not as much as you would if you were just to stop and take a full rest period. But why not stop and take a full rest period? You'd be able to continue to exert that force over more reps, right?

Yes, that is true. You could do the same amount of volume or much more but with less density. But the value of clusters is they do this mysterious thing to your nervous system, saturate your muscles with midi-chlorians…then a miracle occurs. No, no! Clusters increase your work tolerance! See? We're getting somewhere here.

Clusters are just one "advanced" thing you can do that helps to increase work tolerance. There are many others. A mistake that is often made, though, is to look at clusters and similar things as a standalone "method". That is almost always how these things are tackled. Clusters are much more useful when they are integrated into a full, and more clever, plan.

A Plan Involving "Speed" Work and Clusters

Man, you can't combine speed work with clusters! Well, no, you can't combine them as in doing them at the same time. Wouldn't make sense at all. But you can combine them within the meaning of one building off the other. I am going to list out a plan I just gave someone. I don't usually do this as training is individual and what one person can handle or what they need can be quite stupid for another person to do. But this is a good example of how one might integrate the concepts I've discussed here.

Before I get to it, a few comments about the "speed" component of this plan. First, it is using fairly high percentages of max so it falls into the "strength-speed" spectrum of things. Second, I just call it speed work to differentiate it from percentage based routines. That is, while all trainees may benefit from it some may benefit from it more if they are actually very slow and need work in this area. However, when the weights are lighter, we always lift them with the intention of moving them as fast and as "explosively" as possible. If you want to call it speed that is fine. If you want to call it something else that is fine. I do want to differentiate it from percentage based routines because of one main component. Those types of routines usually rely on some "1RM" established at some point in the past. As I've explained many times in my writings, I do not agree with this approach whatsoever.

So, let's say you have lifted 450 pounds once. Maybe a few weeks ago. But you know you can lift 330 to 440 "any day of the week" so to speak. In that case, it would be reasonable for you to choose 440lbs, 435lbs, or 440lbs as your "max" and base your percentages off of that. Being conservative is fine. You do not have to be precise as you will be working up to very high percentages, beyond speed work, and then performing clusters and there will be a great challenge in this. But if you were to choose the 450, that you've only lifted once and haven't been able to match consistently then you will likely be overshooting and be unable to handle the plan. So we want heavy enough but not too heavy.

If you just don't have a clue, however, you should work up to a relative max on the first day. This means that using appropriate warmups and acclimation sets you will work up to one single that is the best you can do that day with very good form. You're not going for a PR here. Just establishing where you are at that moment while showing good performance. It should be challenging but not crazy challenging! This plan assumes you are a very advanced lifter and that you have worked with these kinds of intensities often. You MUST be able to handle high volume with high intensities and this assumes that you are a mature lifter. So, I provide this example as an illustration of where we can take such a concept but I am not recommending that very many trainees undertake this, at least without consultation and supervision. If this constitutes a very abrupt "intensification" of training for you…then you should know better than trying it. To be clear, this is NOT for the recreational lifter!

For those able to pick their max, reasonably as described, you have the option of working up to a heavy double or triple on the first day, before the speed work. This is up to the individual. Some will find that their speed improves from doing this. Some will find it to be too much. It depends on your work tolerance (ding!) and your response to heavy lifts. If you feel unable to do this you can warm up to a weight that is about 10lbs heavier than your target working weight, or you can skip it altogether.

On the second session, there should be no heavy sets. Just a proper warmup and straight to the speed work. Likewise with sessions 3 through 5. Here is the first five weeks of this eight-week plan with the working sets written out, based on a max of 435 (whether relative or guesstimated) as discussed. They go from strength-speed to strength:

1. 75% = 325 x 2 x 8 to 10 sets (working on technique but fast as possible) 2 minutes or so rest periods
2. 80% = 345 x 2 x 2 x 8 to 10 (lift it like you mean it but still work on technique)
3. 85% = 370 x 2 x 6 to 8 (gettin heavy!)
4. 90% = 390 x 2 x 6 (circa-maximal)
5. 95% = 410 x 2 x 4 (is this guy crazy? Stick with 4 unless you are feeling very good about doing more)

This ends the strength-speed to strength work, covering 5 weeks. Here you have had the opportunity to reestablish some good habits while doing some very aggressive work. For some this may be the most aggressive kind of thing you've ever done. I would encourage you not to do it if you are anxious about it as that is usually a signal one isn't ready. There are other ways to get to this level and you simply need a lot of work with heavy weights prior to this. The rest periods should remain fairly constant throughout this period. This is important. Remember this is all about manipulating rest and recovery, it's not just about lifting weights as heavy as possible.

As hard as the weights may seem to some the real challenge here is attempting to maintain the short rest periods throughout. It would not be reasonable to expect the 2 minutes to be maintained all the way from 75% to 95%. The point is to make a valiant effort to do this while keeping safety in mind. Do not take unnecessary risks. Week 6 lets you "take a break" by increasing the rest periods but maintaining the weight. In effect, you will be repeating the workout of session 5 but allowing much more recovery between sets. This way you have challenged recovery and force potential and then you allow a bit more recovery while maintaining force output.

After that, you will take the same sets and reps and turn them into clusters. So in this scenario, you will have performed a second workout with 410 X 2 X 4, using longer rest periods, on week six. Now you will insert mini rest periods of 15 to 20 seconds between each rep within a set, hoping this allows you to turn the 2 reps into 4 reps. You will do one "cluster set", rest normally, and then perform another cluster. Etc. You can stop at 3 clusters if you are unable to continue or you can go for the whole enchilada and do 4 clusters:

6. 410 x 2 x 4 (5 to 7 minute rest periods between sets)
7. 410 x (4x1) X 3 to 4 (where the 4x1 is a cluster of 4 reps w/15 to 20 secs. rest between, a normal rest of 5 to 7, and then repeated clusters for up to 4)
8. 410 X (4x2) X 2

As you see all we've really tried to do is increase the reps over a very short additional time and without allowing full recovery between reps. Going from 8 reps to 12 to 16 was hard enough. On week 8 we double up the reps, still using the min rest between doubles. Our recovery is challenged even further and the whole time we have been maintaining the same force output..which is VERY high.

We have manipulated rest and in so doing manipulated fatigue. Remember that I defined endurance as ability to maintain force over time (whether sustained or reps). Well, fatigue could be defined as the inability to maintain force over time (for us at least). Here, we have worked under fatigue conditions while trying to only stave off fatigue a little. In other words we've tried to resist the affects of fatigue just enough to maintain force but not more than enough. "Not more than enough" is a very important component here. By manipulating recovery just enough and so resisting fatigue just enough we have worked on tolerating fatigue and thus we have developed more work tolerance.

To understand this, relate it to the lactic acid tolerance training I described above. If the rest periods used were so long that lactic acid was able to be completely cleared nothing would be accomplished! It's the same here. If we rested long enough to allow complete recovery we would not increase our work tolerance. Our ability to maintain this force in the face of fatigue says a lot about our ability to increase force output. Many will find that their actual max attempts are "easy" compared to this work with already established weight ranges.

You should have noticed that while endurance work usually involves lots of sub-maximal repetitions this used near-maximal weights. What we want then is the simple ability to withstand a lot of near maximal work. Under all sorts of conditions, not just "ideal" ones. One of the failures of "strength training theory" is that most of it uses ideas borrowed from sports that never use maximal muscular effort. The same idea about periodization for a swimmer is recycled for strength training. The problem with this is that it tends to involve ideas about monitoring performance and recovery as if you are in fear for your life if you try to lift a heavy weight when "not properly recovered." We want the opposite. We want to be able to tolerate near maximal work even when things are not ideal. Without risking injury and without compromising recovery to the extent that training is disrupted.

This plan is an extreme example that would not suit many right off the bat so you may wonder why I used such an "advanced" plan to illustrate this. Well, if I give a more basic plan it would be more difficult for you to tell the difference between this and many other ways of training that involved volume or increasing endurance. So this served to better illustrate what we are going for even though being this aggressive will not at first be necessary. The example should help you see how we think about it even if it doesn't suit you personally.

One Last Note, Defining Fatigue

Since the word fatigue is used prominently throughout this article, I think it is important to establish a working definition for it, since fatigue can mean different things to different people. Of course, by fatigue, we mean that things are going on inside your body, on a physiological and chemical level, and these things constitute what scientists might consider fatigue. Also, when you feel the physical effects of your training and other activities, you are tired, sluggish, uncoordinated, etc. that is an outward manifestation and we call that fatigue as well.

Here though, when I talk about manipulating fatigue, I am thinking of fatigue as that component or "factor" that masks your fitness, which in this instance is your force output ability. This is important because it is different from the classic view that has fatigue as making "inroads" on your recovery ability and which would cause you to model training very differently.

1. Bompa, Tudor O., and Michael Carrera. "Strength and Energy Systems." Periodization Training for Sports. Champaign, IL: Human Kinetics, 2005. 32-33. Print.

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This page created 20 May 2011 22:17
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