summarize this first part: 
summarize this in key points. do not leave any key information:
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couple of key variables that I'll spell
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out for you and if you do that you can
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greatly increase muscle hypertrophy
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muscle size and or muscle strength 80 to
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90 percent and you don't necessarily
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have to use heavy weights in order to do
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that weight training unlike a lot of
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other forms of exercise has a unique
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aspect to it which is this feature that
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I guess some people call it the pump
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which is the fact that blood goes into
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the muscle when you train it's the only
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kind of training where you actually get
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a window into what the result might
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actually look like before you actually
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accomplish that result most people when
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they hear the word muscle they just
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think about strength but of course
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muscles are involved in everything that
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we do they are involved in speaking they
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are involved in sitting and standing up
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they're involved in lifting objects
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including ourselves they are absolutely
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essential for maintaining how we breathe
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they are absolutely essential for
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ambulation for moving and for skills of
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any kind
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so when we think about muscle we don't
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just want to think about muscle the meat
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that is muscle but what controls that
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muscle and no surprise what controls
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muscle is the nervous system we have
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upper motor neurons in our motor cortex
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so those are in our in our skull and
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those are involved in deliberate
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movement so if I decide that I'm going
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to pick my pen up and put it down which
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is what I'm doing right now my upper
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motor neurons were involved in
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generating that movement those upper
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motor neurons send signals down to my
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spinal cord where there are two
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categories of neurons
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one are the lower motor neurons and
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those lower motor neurons send little
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wires that we call axons out to our
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muscles and cause those muscles to
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contract they do that by dumping
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chemicals onto the muscle anytime we're
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walking or doing something where we
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don't have to think about it to do it
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deliberately It's Just Happening
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reflexively that Central pattern
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generators and motor neurons anytime
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we're doing something deliberately that
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the top down control as we call it from
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the upper motor neurons comes in and
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takes control of that system muscle is
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metabolically expensive and indeed
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compared to other tissues compared to
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Fat compared to Bone compared to almost
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all other tissues except brain tissue
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muscle is the most metabolically
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demanding which is why people who have
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more muscle relative to adipose tissue
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to Fat they can eat more and they're
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more of a furnace they just kind of burn
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that up if you've ever carried a box
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while moving or you're carrying heavy
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groceries to the car or you're
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exercising particularly hard and you
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felt the burn well that burning so when
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you feel that burn that is not lactic
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acid that is lactate that's present to
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suppress the burn to suppress acidity
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it's also a fuel when you feel that burn
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lactate is shuttled to those areas of
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the muscle and there's an actual fuel
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burning process where in the absence of
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oxygen you can continue to generate
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muscular contractions here's a reason
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that regardless of what kind of exercise
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you do if it's weight training or
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running or cycling or swimming that
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every once in a while about 10 percent
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of the time you should exercise to the
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point of intensity where you start to
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feel that so-called burn what I'm
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telling you is that if you feel a burn
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from a particular exercise or movement
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that burn is going to be buffered by
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this molecule we call lactate lactate
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will then provide additional fuel for
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additional work that burn is a acts as a
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big to the lactate which comes in and
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allows you to do more work it's not a
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signal to stop the reason for that is
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that lactate shows up
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to the site of the burn and it acts as a
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hormonal signal for other organs of the
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body in a very positive way everything
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about muscle hypertrophy about
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stimulating muscle growth is about
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generating isolated contractions about
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challenging specific muscles in a very
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unnatural way whereas with strength it's
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about using musculature as a system
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moving weights moving resistance moving
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the body