Other/Mixed New training block, Isometrics as primary resistance training

[3letterslong]

Huh. You guys have me thinking about Jon Bruney's Neuro-Mass workout in a new light. It divided training into pull, push, squat, hinge, calves, grip and hit each area with supersets that were formatted like this:

1. heavy grind 6-12 reps
2. all-out ballistic 30-45 seconds
3. isometric hold 6-12 seconds

I really liked it, but I was using it as a kind of HIT/HIIT workout where I'd incur a heavy recovery debt by pushing myself to failure 3 times in a single set. Thinking about it as tension ----> metabolic stress -------> tension wouldn't really change much, but that shifted perspective might even make it a more productive workout.

I think I'll try a training block like this in the fall.

 

[North Coast Miller]

Edit: The idea of deliberately mixing strength work with cardio is similar, not that it is in any way the same program! It could give a similar purpose and benefit though.

Not many forms of resistance work can be paired with cardio, let alone ones that target high threshold motor units. Iso is almost uniquely qualified for this role, and rather than just 'what is possible' seems to be improved by it.

 

[chronos33]

There will def be some local use of lactate and ROS production, but we know it is not as high as traditional resistance work.

What do you exactly mean by that? Do you mean that isos produce less ROS and lactate than traditional resistance work? I know that isos don't produce as much muscle damage, but do they produce less lactate and ROS production too?

As a side bonus, this can produce some HIIT-esque aerobic benefits in the same session.

Oh yeah I agree, getting HIIT benefits at the same time sounds like a sweet deal. You are definitely preaching to the choir with me, especially because my main goal is concurrent training mainly for health reasons. If anything I am much more of an endurance person than resistance one. But to get the most benefits possible doing both endurance sports and resistance training is a no brainer.

There was a great article by Stronger By Science about adding cardio for mostly strength/hypertrophy oriented athletes and if anyone has time I feel like it is well worth reading. The article also barely talks about the multiple health benefits of endurance training but it was not the main point of the article.

Also if anyone else reading all this endurance talk is wondering about the interference effect, it might not be as much of an issue as mentioned elsewhere. For a while it was thought that concurrent training cardio and resistance exercises would kills your gains but most experts do not seem that much worried about it nowadays. Most of them still recommend to separate your resistance training sessions and cardio sessions by at least a few hours or on different days if possible, but to me it seems like more of a safe recommendation than something set in stone.

I really liked it, but I was using it as a kind of HIT/HIIT workout where I'd incur a heavy recovery debt by pushing myself to failure 3 times in a single set.

Oh yeah trying to combine both HIIT and resistance training in one session is super hard. I did something similar where I would do a circuit training style session with barely any rest in between exercises. I did 15 seconds iso of exercise #1, 15 seconds rest to switch to new exercise, then 15 s of exercise #2 and keep going like that with 15 s rest in between each exercise. Even though I would be done in less than 20 minutes I would be super gassed and it would take me long time to recover from that. I decided to take more rest in between each iso to focus more on strength and less about HIIT but it might be worth revisiting.

Honestly if systemic lactate is your goal then doing rope jump in between isos might not even be necessary, just reducing rest time in between exercises might be another option. It mostly depends on your goals and what you are trying to do. I guess what I am talking about is more similar to a crossfit style of training where you switch from one exercise to another without enough time to fully recover in between.

 

[North Coast Miller]

What do you exactly mean by that? Do you mean that isos produce less ROS and lactate than traditional resistance work? I know that isos don't produce as much muscle damage, but do they produce less lactate and ROS production too?


Oh yeah I agree, getting HIIT benefits at the same time sounds like a sweet deal. You are definitely preaching to the choir with me, especially because my main goal is concurrent training mainly for health reasons. If anything I am much more of an endurance person than resistance one. But to get the most benefits possible doing both endurance sports and resistance training is a no brainer.

There was a great article by Stronger By Science about adding cardio for mostly strength/hypertrophy oriented athletes and if anyone has time I feel like it is well worth reading. The article also barely talks about the multiple health benefits of endurance training but it was not the main point of the article.

Also if anyone else reading all this endurance talk is wondering about the interference effect, it might not be as much of an issue as mentioned elsewhere. For a while it was thought that concurrent training cardio and resistance exercises would kills your gains but most experts do not seem that much worried about it nowadays. Most of them still recommend to separate your resistance training sessions and cardio sessions by at least a few hours or on different days if possible, but to me it seems like more of a safe recommendation than something set in stone.


Oh yeah trying to combine both HIIT and resistance training in one session is super hard. I did something similar where I would do a circuit training style session with barely any rest in between exercises. I did 15 seconds iso of exercise #1, 15 seconds rest to switch to new exercise, then 15 s of exercise #2 and keep going like that with 15 s rest in between each exercise. Even though I would be done in less than 20 minutes I would be super gassed and it would take me long time to recover from that. I decided to take more rest in between each iso to focus more on strength and less about HIIT but it might be worth revisiting.

Honestly if systemic lactate is your goal then doing rope jump in between isos might not even be necessary, just reducing rest time in between exercises might be another option. It mostly depends on your goals and what you are trying to do. I guess what I am talking about is more similar to a crossfit style of training where you switch from one exercise to another without enough time to fully recover in between.

I've done a lot of reading trying to find the relative metabolic cost of iso to trad and there is not a lot out there. What is, doesn't do a good job of matching workloads etc, so largely useless in that respect.

It has been noted that iso does not trigger as much of an increase in insulin sensitivity immediately after, and separately that there is less oxidation occuring. These two factors lead to a single conclusion - not much glycolysis going on here, at least not burning much pyruvate.

Anecdotally I burn not many more calories doing only iso as I do not training at all, so my conclusion - metabolic turnover is not high. I am ready and eager to be proven wrong on this, but I don't think so...

This all leads to my blanket recommendation to do some form of glycolytic training with your iso. Is almost required.

 

[bluejeff]

It has been noted that iso does not trigger as much of an increase in insulin sensitivity immediately after, and separately that there is less oxidation occuring. These two factors lead to a single conclusion - not much glycolysis going on here, at least not burning much pyruvate.

Anecdotally I burn not many more calories doing only iso as I do not training at all, so my conclusion - metabolic turnover is not high. I am ready and eager to be proven wrong on this, but I don't think so...

This is interesting. As someone who has not spent much time with overcoming isos, but has spent quite a bit of time with yielding isos, I have a hard time believing that not much glycolysis is going on, at least in the latter. I'm not contesting the claim; it's just that anecdotally, the amount of burn that can be accumulated doing yielding isos at least suggests to me that there is definitely some metabolic "stuff" going on. I believe I've seen users of extreme isometrics report hypertrophy. It would be interesting to look at the progression of calisthenics athletes who are focused on static skills. The only trouble is that many of them try to stay light to make the skills easier to perform...so sorting out hypertrophy effects would be hard.

Perhaps overcoming isos (especially done in short "sets") have less "metabolic stuff" going on in them compared to yielding, for some reason?

Are you referencing certain research regarding the bits about insulin sensitivity and oxidation?

 

[North Coast Miller]

This is interesting. As someone who has not spent much time with overcoming isos, but has spent quite a bit of time with yielding isos, I have a hard time believing that not much glycolysis is going on, at least in the latter. I'm not contesting the claim; it's just that anecdotally, the amount of burn that can be accumulated doing yielding isos at least suggests to me that there is definitely some metabolic "stuff" going on. I believe I've seen users of extreme isometrics report hypertrophy. It would be interesting to look at the progression of calisthenics athletes who are focused on static skills. The only trouble is that many of them try to stay light to make the skills easier to perform...so sorting out hypertrophy effects would be hard.

Perhaps overcoming isos (especially done in short "sets") have less "metabolic stuff" going on in them compared to yielding, for some reason?

Are you referencing certain research regarding the bits about insulin sensitivity and oxidation?

Yes, I'd have to dig back to find the references. As mentioned, these weren't what I would consider definitive studies, rather observations from research that might be applicable. The lack of insulin response was from a rat study IIRC. The lack of oxidative metabolism was from a human study, but they didn't use comparative values from traditional resistance work, only a general statement. Presumably its buried in the references.

Re hypertrophy from extreme isos, I'm waiting for a report back from someone who only used them for a dedicated block, and gained notable hypertrophy. I have maintained what most folks would consider a goodly amount of muscle using only iso, presumably someone fairly light could use it to gain mass. But at some point the lack of metabolic turnover def seems to hurt hypertrophy. When I crested 200lbs, gaining 10lbs in just over 3 months, was using iso with sprint in place intervals.

The rhythmic contract and relax is big part of what generates glucose turnover in the muscle - what's there might be mostly consumed but I'm agnostic on how much more is happening in the absence of more dynamic movement or contraction. I am likewise ignorant of just how much turnover is needed to cross the threshold.

Which isn't to say there is no hypertrophy even from static iso training of relatively short efforts. The pulses def produce some turnover and a bit of blood occlusion, and a newbie will almost certainly put on some muscle. But...the scale doesn't lie. If I only use iso I have to cut back on calories or I'll begin to gain bf. Not muscle and fat, just fat. The inclusion of a relatively modest amount of glycolysis is enough to flip the switch.

You'd think the state of research would have more answers than this, but I haven't found em yet. Am going just by n=1 cause and effect.

 

[chronos33]

Oh that is neat I think this is the first time we fundamentally disagree on something @North Coast Miller. I think my opinion is more in line with @bluejeff 's .

I'd like to add a few caveats to my explanations below before I start:

1. I have never studied biochemistry / biology and my background is in a completely unrelated STEM field. I am just a curious dude who likes learning stuff.
2. My knee-jerk reaction to whether or not metabolic stress is higher in isos vs traditional resistance training is almost the opposite of your position. I believe that isometric produces similar metabolic byproducts than regular resistance training and the difference between the two might not really be that important . If anything, there are good reasons to believe that isos might actually produce more metabolic stress than regular training.
3. My main focus of interest has been endurance training for a long time and a lot of what I learned about exercise physiology (lactate, energy production, mitochondrial adaptations, etc.) comes from this point of view. From an endurance training perspective, people usually come at this from the exact opposite side where maximizing fat oxidation and producing the least amount of metabolic stress as possible is the end goal.

Now let me explain why metabolic stress might actually be higher than regular training.

During exercise, there are mostly 3 ways of generating energy, either we breakdown Phosphocreatine (PCR) to generate ATP (anaerobic alactic), we burn glucose during Glycolysis (either anaerobically or aerobically) or we break down fats (aerobically). These 3 ways always coexist on a spectrum where you never fully turn off one or the other, your body usually turns the knobs more or less depending on the intensity of the exercise and the energy required. Note that my explanations are quite simplified because reality gets way more complex and messy. I am also not gonna talk about how lactate can be reused as a fuel or other pretty niche fuel sources like ketones or amino acids. And I won't really mention how PCR is resynthesized.

Usually, as a rule of thumb you can view the PCR system as the fastest way to generate ATP and fat oxidation as the slowest. In this order: PCR => Anaerobic Glycolysis => Aerobic Glycolysis => Fat oxidation.

We know that anaerobic glycolysis (also called anaerobic lactic energy system) results in negative byproducts. At first, byproducts like lactate and hydrogen ions appear in the muscle locally and the muscle can keep clearing them by itself. If the intensity of the exercise is too great and the duration too long, the muscle can't keep up and the byproducts end up in the blood for the rest of the body to clear (that is why we breathe harder among other things, not just because we need more oxygen but also to get rid of some byproducts). That is what makes things like lactate raise in the blood during exercise.

So far so good, that is nothing new. Here is where we start to disagree:

The rhythmic contract and relax is big part of what generates glucose turnover in the muscle - what's there might be mostly consumed but I'm agnostic on how much more is happening in the absence of more dynamic movement or contraction. I am likewise ignorant of just how much turnover is needed to cross the threshold.

One thing that I have always hated about energy systems discussions in general is that it might just be me but I feel like there is always a missing step in most people's explanations. When you eat carbohydrates your digestive system breaks down the carbs and absorbs them as glycogen in the liver and the muscles. When you start exercising, if your body needs energy quickly you are gonna start to quickly break glucose into ATP during glycolysis.

But wait, where is that glucose coming from? I thought we were talking about glycogen, what happened to it? Well, when you exercise your liver breaks down that glycogen into glucose and releases it in the blood to provide the muscles with an extra boost. That is absolutely true and provides a good source of energy during endurance sports for example (unrelated but cool fact, that is why pro cyclist are consuming up to 120 g of sugar per hour nowadays!). But, the big thing missing is what happened to the muscle glycogen?

It appears that muscle glycogen becomes more and more important the more intense the exercise becomes. Here is a great review that explains all of what I said earlier much better. It goes in details about the different energy substrates used during exercise. Here is a relevant snippet:

During very intense efforts lasting seconds (such as throws, jumps or 100- to 400-m sprints) or during intermittent game activities and field sports, most ATP is derived from the breakdown of phosphocreatine (PCr) and glycogen to lactate. Direct measurements of muscle PCr and glycogen before, during and after such exercise bouts show substantial decreases in the levels of these substrates

And here is figure 3 which is quite relevant for our purpose here:



We can see how the higher the exercise intensity, the higher the contribution from muscle glycogen as opposed to plasma glucose. Now I know that this is an example of endurance sports where they only reached 85 % of VO2max, but resistance training goes at much higher intensity for the muscle worked and is not sustainable for a long time. The muscles worked during resistance training need even more energy and they need it quickly. That energy needs to come from somewhere which is primarily muscle glycogen through glycolysis and not through blood glucose levels.

So blood glucose is not the primary source of energy during resistance exercise and muscle glycogen is. But there still is the question about whether or not that muscle glycogen is used aerobically or anaerobically. If it was used mostly aerobically, then in that case isometrics would not produce a lot of metabolic byproducts.

(By the way just like you I have not found any relevant study on this subject, this is so niche that I understand lol)

Despite not finding any relevant studies, I think we can still make an educated guess on whether or not isometrics causes more metabolic stress than regular training. We know that isometric contractions basically cuts off all the blood from coming in or out of the muscle. That means that the byproducts from anaerobic glycolysis can't get out of the muscle until the muscle relaxes. But it also means that new oxygen cannot get in. If all the oxygen is consumed, the muscle is only left with anaerobic energy systems. Hence why if anything there are good reasons to believe that isos might actually produce more metabolic stress than traditional resistance training.

So in summary, lactate and other metabolic stress markers raise with both exercise intensity and with exercise duration. This happens in traditional resistance training, in endurance training but also in isometric training :

I have maintained what most folks would consider a goodly amount of muscle using only iso, presumably someone fairly light could use it to gain mass. But at some point the lack of metabolic turnover def seems to hurt hypertrophy. When I crested 200lbs, gaining 10lbs in just over 3 months, was using iso with sprint in place intervals.

Which isn't to say there is no hypertrophy even from static iso training of relatively short efforts. The pulses def produce some turnover and a bit of blood occlusion, and a newbie will almost certainly put on some muscle.

This is one of those cases where n=1's are really hard to generalize. Results are hard to dispute and personal experience is for sure important. But this is one of those things where it is hard to truly know for sure the impact of one training variable over the other. It feels almost impossible to truly control everything in an experiment.

For example I can anecdotally confirm that I too managed to gain a lot of muscle mass with only isometric training without directly trying to raise systemic lactate (though it probably did anyways). I tracked my weight progression and got the heaviest I have ever been where I gained 14 lbs in just 4 months and a lot of it was muscle mass. Then I cut, rebulked, and recut to try and make sure that my weight comparison was fair from the beginning of the experiment the end. After 13 months I am fairly confident that I gained 15 lbs of muscle mass in a year (if anything I think I am less fat now but this is highly subjective and debatable). With all that being said, I would not be surprised if someone managed to gain significant muscle mass by doing only extreme isos provided that they keep reaching true failure and that the load is significantly high.

Honestly this is one of those cases where if you found something that works, I really don't see any reasons to change it, especially when as you said you can also gain some HIIT-esque benefits. In my book that is definitely a win.

(Sorry for it being that long! I did not really expect to write that much lol! I hope someone still managed to read the whole thing ).

 

[Training for Life]

Lots of valuable information in this thread, thank you for contributing.

Question regarding the need for metabolic stress to trigger hypertrophy. Do you reckon that simply tiring a muscle out is sufficient, or should one look to elevate their heart rate above aerobic threshold?

 

[North Coast Miller]

Lots of valuable information in this thread, thank you for contributing.

Question regarding the need for metabolic stress to trigger hypertrophy. Do you reckon that simply tiring a muscle out is sufficient, or should one look to elevate their heart rate above aerobic threshold?

I don't think HR has much to do with it.

 

[North Coast Miller]

This is one of those cases where n=1's are really hard to generalize. Results are hard to dispute and personal experience is for sure important. But this is one of those things where it is hard to truly know for sure the impact of one training variable over the other. It feels almost impossible to truly control everything in an experiment.

This is where I'm waiting to hear from someone who dedicates a 12 week block to isolating specific adaptive response. There really is no other way. I was listening to a podcast where a coach was using it several times a day, not for hypertrophy or even strength but as a restorative from all the other training they were doing. Hmmm...you can't add a high response stimulus to an already demanding schedule.

With all that being said, I would not be surprised if someone managed to gain significant muscle mass by doing only extreme isos provided that they keep reaching true failure and that the load is significantly high.

The issue is the same you run into with high rep/moderate or low load external resistance. Your bodyweight doesn't really constitute a heavy load. Unlike with overcoming iso you are not starting out with high threshold MUs being recruited at a high %, you need fatigue to change recruitment focus. If you did your extreme iso with a weighted vest or a strap and board setup etc, the dynamic might be very different, but then it would be overcoming iso with a DropSet-esque finish.

Research from metabolite signalling generally demonstrate anything over 70% mvc is predominantly type 2. At longer duraction this is liable to kick over to type 1, accompanied by a large reduction in force production. I am not clear on the effect of muscle not changing length on CrP economy, lactate usage, type 2a usage of initial 2 or 3 atp from glycolysis. Given the preferential recruitment of type 2, there should be a large spike in lactate from the unused pyruvate, and there doesn't seem to be, or the large boost in insulin sensitivity would be present. Would be great to see if markers from the Cori Cycle become elevated following.


The research that exists consistently demonstrates a reduced effectiveness for iso compared to traditional resistance work in improving insulin response and glucose metabolism generally, this is from a number of studies. This is not to say there are no benefits, but the magnitude is less. I haven't found anything directly comparing blood lactate levels...

The simple fact that I can even use intervals with overcoming iso tells me the metabolic cost must be much much less than traditional resistance done at high intensity. When I combine iso with moderate load external resistance I absolutely do not have the additional bandwidth for anything more than fast and loose, often not even that.

As mentioned, am happy to be proven wrong on this, but the current state of research is not much help.

 

[North Coast Miller]

Another interesting observation, a long run of iso, even using HIIT for a catalyst, leaves one perpetually having that "day after" look. I never get really pumped, but the next day I look like I did a hard workout the day before, possibly better aesthetic than from traditional training.

Going back to traditional or a mix of trad and iso as I am currently doing - I get pretty dang pumped. I do recall a conversation with someone a while back recommending they run a week of traditional training after a block of iso to get a fair gauge of their hypertrophic results. It isn't evident so much without a bit of pumpitude. I also suspect transient blood volume might be reduced from a selective run of only iso, another factor in total mass gain and aesthetic.

 

[3letterslong]

The issue is the same you run into with high rep/moderate or low load external resistance. Your bodyweight doesn't really constitute a heavy load. Unlike with overcoming iso you are not starting out with high threshold MUs being recruited at a high %, you need fatigue to change recruitment focus. If you did your extreme iso with a weighted vest or a strap and board setup etc, the dynamic might be very different, but then it would be overcoming iso with a DropSet-esque finish.

I just want to remind everyone I'm not an expert before I jump into this debate because I'm waaaaaay out of my depth in this discussion, but my understanding of Extreme Isometrics was that it's maximally pulling yourself into position -- you're basically doing overcoming isometrics against the end of your ROM. I think with a perfectly-working body, you would get a synergism that creates a high recruitment percentage.

For instance: in the push-up, I would be pulling as hard as I could with my back muscles and my push muscles would be stretched to such an extreme that there was no way in heck I could ever push myself out of such a disadvantaged position. Both pull and push were experiencing what I would consider a heavy load.

But, I didn't have the flexibility in my hips to experience the same dual high efforts in my lunges. When I was in proper athletic alignment to execute the pull in the optimal movement pattern, my legs weren't at extreme enough joint angles to achieve that loaded stretch experience. (I have a feeling this flexibility issue would have taken care of itself if I kept doing extreme isos until my flexibility improved enough to hit that extreme ROM). BUT I'm not sure quads would ever see intense loading in the beginning stages, even with maximal stretch. Schroeder eventually graduates from wall sits to one-legged holds at the bottom of a step-up position and it's only then you might see the quads really challenged.

Looking back at my results, my hypertrophy was most pronounced in the muscles that were loaded under an extreme ROM (chest muscles, lats) with additional hypertrophy appearing in the muscles that did the overcoming isos against the end of the ROM (mid/upper back, shoulders, hamstrings). In my experience, the biggest problem with Extreme Isos was hitting each muscle group properly. For instance, my triceps and biceps never experienced any kind of overload. I think this is why Schroeder included bicep curls in his seven movements and I'm pretty sure my triceps would have experienced the same growth as my chest if I had been doing dip holds at the bottom of the movement instead of the top.

 

[Ege]

I would like to enter to this debate by asking a question Is SF’s slow twitch fiber hypertrophy protocol has anything to do with this debate?

 

[GreenSoup]

I would like to enter to this debate by asking a question Is SF’s slow twitch fiber hypertrophy protocol has anything to do with this debate?

Years ago I recall Pavel had said isometrics could be used in the Q&A in one of the slow fiber articles on the site. It might be worth a search to see what his exact comments were to apply them fully.

 

[North Coast Miller]

I would like to enter to this debate by asking a question Is SF’s slow twitch fiber hypertrophy protocol has anything to do with this debate?

Probably not, but there are a bunch of ways to apply isometrics. Overcoming iso has very little in common with super slow, sub-max effort.

 

[North Coast Miller]

I just want to remind everyone I'm not an expert before I jump into this debate because I'm waaaaaay out of my depth in this discussion, but my understanding of Extreme Isometrics was that it's maximally pulling yourself into position -- you're basically doing overcoming isometrics against the end of your ROM. I think with a perfectly-working body, you would get a synergism that creates a high recruitment percentage.

For instance: in the push-up, I would be pulling as hard as I could with my back muscles and my push muscles would be stretched to such an extreme that there was no way in heck I could ever push myself out of such a disadvantaged position. Both pull and push were experiencing what I would consider a heavy load.

But, I didn't have the flexibility in my hips to experience the same dual high efforts in my lunges. When I was in proper athletic alignment to execute the pull in the optimal movement pattern, my legs weren't at extreme enough joint angles to achieve that loaded stretch experience. (I have a feeling this flexibility issue would have taken care of itself if I kept doing extreme isos until my flexibility improved enough to hit that extreme ROM). BUT I'm not sure quads would ever see intense loading in the beginning stages, even with maximal stretch. Schroeder eventually graduates from wall sits to one-legged holds at the bottom of a step-up position and it's only then you might see the quads really challenged.

Looking back at my results, my hypertrophy was most pronounced in the muscles that were loaded under an extreme ROM (chest muscles, lats) with additional hypertrophy appearing in the muscles that did the overcoming isos against the end of the ROM (mid/upper back, shoulders, hamstrings). In my experience, the biggest problem with Extreme Isos was hitting each muscle group properly. For instance, my triceps and biceps never experienced any kind of overload. I think this is why Schroeder included bicep curls in his seven movements and I'm pretty sure my triceps would have experienced the same growth as my chest if I had been doing dip holds at the bottom of the movement instead of the top.

My issue with the extreme iso relative to hypertrophy at least, but also strength - it inverts the relationship between iso and muscle length. Yes it applies tension to the muscle at long length, but the tension is in spite of trying to relax it into a longer length, and not from exerting maximally or ballistically at long length. The muscles that are exerting maximally are at short length. These two factors combined lead me to believe the extreme isos are not really intended to be used for max strength or hyperyrophy, and are also intended to be used for other qualities with specific dynamic work, as Schroader does.

And ultimately (in my philosophy at least) any strength or hypertrophic response has to be compared to the results from a spirited use of traditional lifting for the same goals.

 

[Lofty75]

Yes, I'd have to dig back to find the references. As mentioned, these weren't what I would consider definitive studies, rather observations from research that might be applicable. The lack of insulin response was from a rat study IIRC. The lack of oxidative metabolism was from a human study, but they didn't use comparative values from traditional resistance work, only a general statement. Presumably its buried in the references.

Re hypertrophy from extreme isos, I'm waiting for a report back from someone who only used them for a dedicated block, and gained notable hypertrophy. I have maintained what most folks would consider a goodly amount of muscle using only iso, presumably someone fairly light could use it to gain mass. But at some point the lack of metabolic turnover def seems to hurt hypertrophy. When I crested 200lbs, gaining 10lbs in just over 3 months, was using iso with sprint in place intervals.

The rhythmic contract and relax is big part of what generates glucose turnover in the muscle - what's there might be mostly consumed but I'm agnostic on how much more is happening in the absence of more dynamic movement or contraction. I am likewise ignorant of just how much turnover is needed to cross the threshold.

Which isn't to say there is no hypertrophy even from static iso training of relatively short efforts. The pulses def produce some turnover and a bit of blood occlusion, and a newbie will almost certainly put on some muscle. But...the scale doesn't lie. If I only use iso I have to cut back on calories or I'll begin to gain bf. Not muscle and fat, just fat. The inclusion of a relatively modest amount of glycolysis is enough to flip the switch.

You'd think the state of research would have more answers than this, but I haven't found em yet. Am going just by n=1 cause and effect.

@chronos33

Relative to hypertrophy, I am 100% convinced of the need for a metabolic component for hypertrophy. My earliest iso experiments used intervals with iso. I gained about 3lbs lean per month for 4 months, comparable to (spirited) traditional resistance work. I switched to alternating days and the effect tapered off. I came back around to this after over a year and with no other change to my iso routine I began to gain muscle mass again.

The 'tension is all' approach leaves too many unanswered questions.

I have many ideas (theories) re metabolic process and how they play into hypertrophy, but bottom line at the minimum breathe throughout - this is important. Also, I don't believe isometric occlusion and BFR are similar dynamic.

I've been struggling with Myofascial injury and discovered that if I do exercises which lengthen the muscle and add tension (swings, farmer's walk, TGUs etc) help and exercises that bring in contractions (presses, pulls for example) hinder it. What I then discovered is that I'm putting on muscle incredibly well, especially doing loaded carries. To me this is 'Dynamic Isometrics'. Time under tension but not static. I've never felt this strong or gained muscle without pulling or pushing anything. I'm a believer and am diving deeper into this. Build it around AXE training protocols for swings - 30 to 50 sets of swings and then some heavy carry/rest/carry work - and there are gains in strength and size to be had.

 

[North Coast Miller]

I've been struggling with Myofascial injury and discovered that if I do exercises which lengthen the muscle and add tension (swings, farmer's walk, TGUs etc) help and exercises that bring in contractions (presses, pulls for example) hinder it. What I then discovered is that I'm putting on muscle incredibly well, especially doing loaded carries. To me this is 'Dynamic Isometrics'. Time under tension but not static. I've never felt this strong or gained muscle without pulling or pushing anything. I'm a believer and am diving deeper into this. Build it around AXE training protocols for swings - 30 to 50 sets of swings and then some heavy carry/rest/carry work - and there are gains in strength and size to be had.

Basically all of my upper body are done vs a shallow hinge or squat with a bit of preload. Upon exertion I can add tension at long muscle length by hinging up or squatting up into the hold. Stretching a muscle ùnder high tension and forcing into a longer length seems to trigger additional hypertrophy, esp at the distal or insertion end of the muscle. This effect can be very pronounced subjectively. The addition of submax isotonic exercise at this point is well worth the effort. You will blow up.

Side note, eccentric exertion at long length is associated with longer muscle fascicle length (more power/speed per contraction time) particularly at the insertion end of the muscle. It is not established if this is an outcome of isometrics...

 

[Lofty75]

Basically all of my upper body are done vs a shallow hinge or squat with a bit of preload. Upon exertion I can add tension at long muscle length by hinging up or squatting up into the hold. Stretching a muscle ùnder high tension and forcing into a longer length seems to trigger additional hypertrophy, esp at the distal or insertion end of the muscle. This effect can be very pronounced subjectively. The addition of submax isotonic exercise at this point is well worth the effort. You will blow up.

Side note, eccentric exertion at long length is associated with longer muscle fascicle length (more power/speed per contraction time) particularly at the insertion end of the muscle. It is not established if this is an outcome of isometrics...

Exactly. Like any wtf situation it is hard to quantify it and it is at times counter-intuitive. But at the end of the day the underlying principle of supersets, drop sets, GVT etc is time under tension. I've also seen great results from AXE training with TRX (think 20-30 sets of 6reps emom) where I can go very deep and hold tension in certain positions so draw out the movement more. Seeing some hypertrophy which many (myself included) would think unlikely from TRX training.

 

[pgomez]

Hmm. This is a very interesting thread.

I'm wondering if adding 15-20 sec sprints-in-place after heavy Turkish get-ups (a semi-isometric lift) would trigger a bit of hypertrophy with them? I'll have to try that with S&S sometime.