Know the HUGE Muscle Building Myth
Lactic acid is required and mandatory for maxing muscle growth. The burn turns into gains.
There’s a decent probability you’ve heard something along these lines. But what? What does the scientific literature say on lactic acid the buildup of other metabolites generally for muscle growth? Let’s take a look.
Before anything else, it’s worth debunking.
Under normal human physiological conditions, lactic acid largely does not exist. Rather, it’s lactate, which is lactic acid minus a hydrogen ion that’s present in humans.
This idea comes from correlational and hypothetical research conducted before the 1990s. Since then, a multitude of higher-quality evidence indicates lactate does not cause fatigue, nor is it a poisonous substance.
Lactate can be a fuel source for muscle and brain function and contributes to an array of other positive things.
This elegant 2014 paper from the USA shows this isn’t the case. Experimentally infusing lactate to high levels alone did not induce pain sensations.
It was only when all three of the metabolites so ATB hydrogen and lactate were concurrently infused to high levels did pain sensations occur, indicating it’s a combination of metabolites that drive the sensations of pain.
So humans don’t truly produce lactic acid. Rather, lactate.
Lactate does not drive fatigue, and lactate alone does not cause pain sensations during intense exercise. But does lactate cause hypertrophy “Muscle Building Myth “?
2- More lactate, More Hypotrophy
The USA nicely summarizes a multitude of papers finding lactate may play a role in muscle hypertrophy through the activation of satellite cells and the activation of various proteins involved in signaling muscle growth.
Yet a major consideration is all of this research is either in nitro-based I. E.
For example- this study found in rats treadmill running for four weeks, consuming lactate and caffeine produced greater muscle hypertrophy versus not consuming these things “Muscle Building Myth “.
3- More lactate, more gain?
What if we injected humans with lactate while working out?
If lactate powerfully stimulated hypertrophy. We would expect this to increase the activation of key proteins involved in muscle hypertrophy.
A 2020 Swedish study did this and found that injecting lactate into subjects, arms throughout leg extension training successfully increased blood and muscle lactate levels.
But it did not increase the activation of key proteins involved in muscle hypertrophy, any more than injecting saline, which is just salt and water.
Although injecting lactate did increase muscle lactate levels, as just noted, the increases were not massive.
It would have been better to directly inject lactate into the leg muscles as opposed to the arm, to produce larger muscle lactate increases.
Nevertheless, other fascinating data still question lactate’s importance for hypertrophy.
Sprinting for 400 meters seems to produce comparable muscle lactate increases to a lower body training session involving five sets of four different core exercises.
Yet we can certainly say lower body training sessions will build more muscle than 400 meters running. Repeated short cycling sprints appear to produce comparable muscle lactate elevations to three sets of dumbbell curls to failure.
Sprint cycling is not going to be the most hypertrophic stimulus in the long run. Different rep tempos, as indicated by this 2009 Japanese paper, produce different lactate increases even when reps are performed to exhaustion.
The literature indicates when reps are performed to failure, a wide range of rep tempos are similar for building muscle. The Japanese paper indicates a slower lowering tempo produces the lowest lactate increases.
Yet some research indicates slower lowering tempos could build more muscle.
Short rests between sets can increase lactate more. But as noted previously at the House of Hypertrophy, longer rests between large muscle mass exercise sets produce more hypertrophy versus shorter rests.
A 2016 English paper found that when training, the leg press and leg extension with these variables resting 1 minute between sets produced greater lactate elevations versus 5 minutes between sets.
Protein synthesis I e the creation of the proteins that make muscles bigger was largely greater after resting for 5 minutes between sets.
This 2021 Brazilian study used a novel method that further questions lactate hypertrophic value.
Subjects train the leg extensions with these variables. One condition rested normally between sets.
A second condition, blood flow, restricted their leg with a cough during the rest between sets, which ultimately led to greater overall lactate elevations versus the first condition.
Yet quadriceps growth ended up being similar between both conditions after eight weeks of training.
Once lactate is produced by muscle fibers, it doesn’t necessarily stay dormant there. It is converted to fuel for contraction, shuttled to other muscle fibers of the same or different muscle, and even shuttled to the body’s organs.
These facts may further blunt the idea. Lactate powerfully drives muscle growth “Muscle Building Myth “.
4- Another metabolism
Lactate is just one metabolite from thousands. That greater metabolite buildup overall leads to more hypertrophy as implicated by a 2019 German review paper that higher reps perform two or close to failure.
We can include blood flow restriction training performed with high reps here too, which likely produces greater overall metabolite buildup versus lower reps.
Yet the literature indicates blood flow restriction, higher reps, and lower reps can all be similar for building muscle.
Some may think, that hypertrophy is similar to the growth stimuli that differ between them. Namely, higher reps and blood flow restriction cause muscle growth through metabolite buildup, while lower rep training causes muscle growth through mechanical tension.
But as discussed in a great 2017 review from the USA, this is most likely false.
Mechanical tension seems to be the most powerful driver of muscle hypertrophy, and, likely blood flow restriction, higher reps, and lower reps all cause similar mechanical tension, thus explaining the similar hypertrophy.
mechanical tension is the force experienced by muscle fibers. Muscle fibers have a mechanosensory that can detect the force produced by them and convert this force into a signaling event that produces muscle hypertrophy.
The process of force being converted into signaling events has the cool name of Mechanotransduction.
To maximize overall mechanical tension, we’d want to recruit as many fibers as possible and have the fibers produce good force levels for a decent duration.
Training two or close to failure accomplishes this regardless of whether blood flow restriction higher or lower reps are used.
Lower reps with heavier loads will instantly involve high tension, and near failure.
Higher reps and blood flow restriction initially involve low mechanical tension, but as you continue repping out and nearing failure, more muscle fibers are recruited, and many fibers may increase their force contribution.
Ultimately, overall mechanical tension ends up being comparable between these things.
The metabolite buildup with higher reps or blood flow restriction training may be a byproduct of their effort and energy utilization to get to or close to failure.
It’s not the cause of muscle Growth Two other fascinating papers demonstrate that metabolite buildup may play a minimal role in hypertrophy.
These two papers had two conditions. One condition involves subjects training normally with sets of reptiles.
The second condition also involved subjects training normally with sets of reptile failure. But once completing this, the train-to-limb had a blood flow restriction cuff applied to it for three to 5 minutes.
This blood flow restriction would have trapped the metabolites in the muscle, and if metabolites could boost muscle growth, this condition should see more muscle growth.
Yet, after eight weeks, both studies found muscle growth was not enhanced when applying the blood flow restriction after training.
One of the papers found it reduced muscle growth in the women’s subjects.
Lactate does not cause fatigue, and lactate alone doesn’t drive the pain sensations during intense exercise.
Solid literature indicates lactate as well as metabolite buildup in general isn’t a powerful driver of hypertrophy, they don’t seem to convert additional gains beyond what’s provoked by mechanical tension.
I don’t want to make the mistake of saying just because more of something I e metabolites does not mean more hypertrophy.
It means metabolites play a 0% role in muscle growth. There may be a threshold beyond which metabolites provide no further hypertrophy.
The threshold may be low, and much of the research overviewed past that threshold, explaining why infusing Lactate during training, higher reps blood flow restriction, or trapping metabolites via blood flow not provided added hypertrophy.
Alternatively, perhaps, metabolites are anabolic at extreme levels not feasible or possible in humans.
Matter of fact much of the in vitro research linking lactate to muscle hypertrophy involved continuous high lactate exposure for two to 6 hours, with some even lasting for days.
More research “Muscle Building Myth ” is required to pinpoint if either speculation holds any truth or if metabolites are completely irrelevant for hypertrophy.
What is clear is that mechanical tension should be your primary focus if the goal is to build muscle, and this is done by just ensuring you’re performing your reps to or close to failure.
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