What is Muscle Hypertrophy? | Physiology and Mechanisms of Muscle Growth in 5 minutes!

[00:00] hey what's up guys it's matt with

[00:01] movement system today we're going to

[00:02] talk about what is muscle hypertrophy

[00:04] so we're going to explain at the muscle

[00:06] fiber level how we're actually

[00:08] going from damaging a muscle to muscle

[00:10] protein synthesis and rebuilding a

[00:12] muscle in the physiology of that cycle

[00:14] let's go ahead and dive into it

[00:23] [Music]

[00:25] okay so to lay the groundwork our goal

[00:27] is to go from smaller bicep

[00:29] to bigger bicep how are we going to do

[00:32] this well

[00:33] when we think about the layers of the

[00:34] muscle fiber we actually have when we

[00:36] think about the whole muscle when we

[00:38] look at a cross section of that many

[00:40] muscle fascicles

[00:42] and those fascicles with different types

[00:44] of fibers are made up of

[00:45] many individual muscle fibers and what

[00:48] we're looking at here is one muscle

[00:49] fiber so what you'll see here is that

[00:52] there are actually many myofibrils

[00:55] making up this one fiber and then what

[00:57] you'll see in orange are

[00:58] satellite cells around the fiber so you

[01:01] may have heard

[01:02] that muscle cells are multi-nucleated

[01:04] and this is actually going to be a

[01:05] really important

[01:07] thing to remember when we're thinking

[01:08] about the process of muscle hypertrophy

[01:10] okay so step one is to actually go from

[01:12] a fiber to a fiber

[01:14] that has had some micro trauma and how

[01:16] do we do that with training

[01:18] these are dr schoenfeld's three

[01:20] mechanisms of muscle hypertrophy

[01:22] mechanical tension metabolic stress and

[01:24] muscle damage

[01:25] so the training that you do and the

[01:27] training that you program as a strength

[01:28] coach or as a personal trainer

[01:30] is going to have some combination of

[01:31] mechanical tension metabolic stress and

[01:33] muscle damage

[01:34] so we can do high rep training that's

[01:36] going to have more metabolic stress we

[01:37] can do heavy loaded training it's going

[01:39] to have more mechanical tension

[01:41] but either way some combination of these

[01:43] three

[01:44] factors are going to actually lead us to

[01:46] causing micro trauma

[01:48] at the muscle fiber level so once we've

[01:51] done training

[01:52] and we've gone to a muscle fiber that

[01:54] has some micro trauma

[01:55] those myofibrils the actin and the

[01:57] myosin within those myofibrils

[01:59] have had some structural damage what

[02:02] we're going to need to do next

[02:03] is muscle protein synthesis so once

[02:06] micro trauma has occurred at the

[02:07] myofibrillar level

[02:09] we actually have a hormonal cascade of

[02:12] things like testosterone and igf-1 and

[02:14] growth hormone

[02:15] that are going to signal that there's

[02:17] been damage and

[02:18] as well activate satellite cells so

[02:21] these are the satellite cells that we're

[02:22] talking about here

[02:23] now this is really important those

[02:25] satellite cells

[02:26] are at the level of dna so that dna can

[02:30] actually encode

[02:31] transcribe amino acids which can then

[02:35] become muscle

[02:36] proteins so these satellite cells with

[02:39] the nuclei in there

[02:40] will actually kind of fill in the areas

[02:42] that have had micro trauma

[02:44] and they will become through a process

[02:47] of dna to amino acids to proteins they

[02:50] will become

[02:51] the myofibrils and that's really

[02:53] important because that's actually the

[02:54] whole principle

[02:56] of adding sarcomeres and making a muscle

[02:58] bigger

[02:59] if this has been helpful for you so far

[03:01] make sure you go ahead and hit that like

[03:02] button

[03:02] and subscribe and turn your

[03:04] notifications on so whenever i make

[03:06] follow-up videos about more things

[03:07] related to muscle hypertrophy and

[03:09] strength conditioning

[03:10] you won't miss them okay so just to be

[03:12] abundantly clear here

[03:13] if this is a muscle cell and there's

[03:16] myofibrils within it

[03:18] what we could do is two things we could

[03:20] either add

[03:21] new and more myofibrils in that would be

[03:24] called

[03:25] hyperplasia and that would occur if

[03:27] those satellite cells grouped together

[03:29] and formed a brand new myofibril that is

[03:32] probably not what occurs

[03:34] as the primary mechanism of muscle

[03:35] growth instead what happens

[03:37] is that those damaged myofibrils

[03:40] actually have satellite cells that come

[03:42] on

[03:42] and make them bigger so that way those

[03:44] current myofibrils

[03:46] actually get bigger and expand the cell

[03:48] and cause muscle hypertrophy that way

[03:50] and just to give you an idea of what

[03:52] this looks like at the cellular level

[03:54] here's a picture so what you can see

[03:56] with this picture is the process of

[03:57] muscle protein synthesis

[03:59] going all the way from an inactive

[04:00] satellite cell that was then

[04:02] activated with the hormonal cascade that

[04:05] came on after muscle damage

[04:06] to then move to a group of satellite

[04:09] cells to then

[04:10] turn those satellite cells into a

[04:13] myofiber

[04:14] so then that myofiber can become part of

[04:16] a myofibril

[04:17] which would make a muscle fiber bigger

[04:19] which would make the entire muscle

[04:21] bigger

[04:21] which we would call muscle hypertrophy

[04:23] so to recap we started with a muscle

[04:25] fiber

[04:26] we did training that involved mechanical

[04:28] tension metabolic stress and muscle

[04:30] damage

[04:31] to then cause micro traumas in that

[04:33] muscle

[04:35] and then what we did was we signaled

[04:37] some hormones

[04:38] and we activated satellite cells to then

[04:41] start to

[04:42] generate new muscle proteins and then

[04:45] that added

[04:46] myofibrils to our muscle fiber which

[04:48] then made our muscle fiber bigger

[04:50] which then made our muscle bigger which

[04:52] then made your biceps bigger

[04:54] importantly though this isn't the only

[04:55] type of hypertrophy what i'm explaining

[04:57] here is the process of myofibrillar

[05:00] hypertrophy which is increasing the

[05:02] myofibrils

[05:03] and increasing the active contractile

[05:06] muscle proteins

[05:07] we could also though have sarcoplasmic

[05:09] hypertrophy of non-contractile proteins

[05:12] if you want me to make a video about the

[05:13] difference between myofibrillar and

[05:15] sarcoplasmic hypertrophy

[05:16] or a video about the sliding filament

[05:18] theory or something like that just go

[05:19] ahead and leave a comment below

[05:21] and i will do follow-up videos to this

[05:22] hopefully this has been helpful for you

[05:24] if it was

[05:25] make sure you go ahead and like and

[05:26] subscribe and if you want to learn more

[05:28] go ahead and join the strength

[05:29] conditioning study group on facebook

[05:31] alright guys thanks for watching and

[05:32] i'll catch you on the next one

[05:41] you