- [Narrator] Today you guys
are in for a real treat. Before we get to the
science on this channel, we often have these fun little intros. You can skip to the science,
but some have told me these are the best part. This story introduces a new
character to our channel very closely based off of one of my not-so-bright roommates from the past. His name is Feswick. I want you to imagine
the ideal lifting buddy. Feswick was the total opposite
of what you're imagining. Mix in the ego and facial
expressions of Derek Zoolander, and you have a Feswick. So we were at the school gym. Now I've been lifting here for a few years and built up a decent strength base, so before I'd hit my working sets, I'd warm up with 20s, 40s, 60s, and 80s before hitting the
hundreds for my main set. Feswick was the kind of guy who was always pretty suspicious,
so when he noticed this, he immediately thought
I was up to something. - You really like to
jump the weights, huh? - [Narrator] Is what he
said, but I'm pretty sure he was thinking more along the lines of. - [Feswick Voiceover] So that's his secret he's not telling me. I just need to make big
jumps in the weights. - Only because I've been
doing this for a long time, so these are my warm-ups. - Right! - [Feswick Voiceover]
He jumps the weights up. If I do that too, I'll
be just as strong as him. He just doesn't want
me to be on his level. - Trust me man, stick with the 45s and you'll make progress real fast. - Faster than you might think. - Huh? - [Girl] Dorian what's up? - Oh hey, I saw you in class. That professor was really annoying, eh? (talking quietly) (dramatic music) (face splats) (dramatic music)
(talking quietly) Dude. - [Feswick] What? - You just dropped a
hundred pounds on your face! - [Feswick] (sighs) You're
still talking about that? Old news. - [Narrator] As I pretended to listen to my girlfriend that night,
I couldn't help thinking back to Feswick attempting to
lift a much heavier weight than he could handle. Was lifting heavy always the way to go? Well, that is gonna
depend more specifically on what your own goals are as we will see. One thing that has been thoroughly proven, regardless of gender or age, resistance training
results in muscle growth. Lifting weights is also called
resistance training because you're contracting your muscle
fibers against resistance. In this case, the resistance is gravity resisting your muscle as you
move the weight through space. Each muscle is made up of thousands of individual muscle fibers. Resistance training
results in this growth. Thanks to a phenomenon
called mechanotransduction where specific sensors in
your individual muscle fibers, known as mechanosensors,
convert this mechanical energy into chemical signals that mediate myocellular, anabolic
and catabolic pathways. In other words, once they
detect that their fiber is under enough load to
trip a certain threshold, they start signaling that the
muscle fiber needs to grow. (electronic beeping) Something important to note also is that not all muscle fibers are the same. While they all contribute
something to every rep range, type one fibers are better
suited to long-lasting endurance while type 2X fibers are better suited for that one rep max explosive power. While some people use weights with the intent on
building their muscle size, others lift weights to train for strength. Lifting can be confusing. People will often tell
you different things. Some will say do high
reps with a light weight to maximize muscle hypertrophy. Others say use a heavy
weight and go until failure. And what about strength? Are heavy weights with low
reps really the only way? The idea that you need to go
heavy is based on the idea that heavier weights are needed
to achieve full recruitment of those higher threshold fibers. The ones that are the most stubborn to sending the growth signal
because optimal improvements in strength and hypertrophy
can only be accomplished when all the fibers in a
muscle have been activated. But what does the research say? In 2016, a meta-analysis was published in the European Journal of Sports Science. Big props to Brad Schoenfeld
for heading this up. It compiled nine studies on this topic and set out to answer this
question once and for all. In all of these studies,
two groups of participants were compared where one
group was lifting weights that were above 65% of
their one rep max strength while the other group was
lifting less than 60%, and both groups lifted the weight until they couldn't do another rep. The meta-analysis acknowledged
that type two muscle fibers, that ones that are better for
heavy weights than endurance, have a 50% greater capacity for growth. And while that is true,
it has been demonstrated that even these fast twitch,
type two muscle fibers, the ones that are best for
intense bursts of strength, are worked by low weight
just to a lesser extent. This is why it isn't entirely
shocking what they found. In terms of muscle gained,
the high and low weight groups both gained a similar amount. How can this be? Well, although a single
rep of a heavier weight verus a lighter weight will
provide greater activation to the type two fibers, the
key lies in the fact that both groups took their sets
to momentary muscle failure. So although the light weight
group got less activation per rep, their sets lasted much longer, and those additional
reps, although they were a lighter weight, continued
to activate the muscle until even the most
stubborn fibers activated. So it looks like both
light and heavy weights, as long as taken to
momentary muscle failure, result in about equal hypertrophy. I say that because although it wasn't statistically significant, there was still a slight trend in favor
of the higher weight. Strength was a different story
because although strength is highly correlated
with muscle hypertrophy, there are various other elements at play. Physiological factors,
psychological factors including confidence and
fear, your motor control and technique, and CNS
adaptations all play a role. These are better trained by
lifting those heavier weights. So if my max bench is 225, whether I train in sets of 135 to failure
or 185 to failure, the muscle hypertrophy
will be about the same as long as total work volume is equal. Whereas my one rep max,
if tested on the spot, might increase slightly more
under the higher load training due to those other factors of strength being more in practice. Lastly, it should be mentioned that muscle size and hypertrophy
aren't one and the same. Because of this, people who do
high reps with light weights may benefit from the
illusion of larger muscles. This is because your
muscles store their energy along with water which can influence how big they look at any given time despite not being the
result of hypertrophy. Glycogen content in the
muscle can significantly alter the apparent size of the
muscle at any given moment. Glycogen is the primary
fuel burned by your muscles after about 10 seconds of activity and continues to be the main
mover until about 120 seconds. The advantage of it is that burning it is an anaerobic process meaning
it doesn't require oxygen, so the power output isn't limited by your ability to breathe in oxygen. If you aren't eating any carbs at all, such as during a fast or keto diet, muscles can look up to 16% smaller. This is why people on
aggressive diets complain that their muscles look really flat. If you are eating carbs,
glycogen is stored in the muscles based on
their predicted need for it. The average person who
doesn't resistance train stores about 350 grams
or so in their muscles, and since each gram is stored
with three grams of water, about 1.5 kilograms, or
three pounds, of muscle bulk in a typical person is glycogen. In body builders who
train in higher rep ranges which often exceed 10
seconds, the body predicts a greater need and stores
more than the typical amount, more than double in fact,
giving them a six to 8% boost in muscle size over the average non-lifter simply from stored carbs. It has been theorized
that someone who trains in low reps mainly for
strength may not see quite as much glycogen
storage in their muscles because these low rep sets
rely less on glycogen. While this theory is often referenced, there has yet to be definitive
proof in the form of a scientific study, but
personally when I went from training in sets
of three to sets of 10, I noticed my muscles appear
fuller as they adapted to my new training demands
by storing more glycogen. But I have to say, and I
think others will agree, going too light does have its drawbacks. Not only do the studies show
a tiny bit less hypertrophy, it can also be harder to
reach an equal volume. Going to failure with a
very light weight can be a lot more agonizing which
is something to keep in mind. So light weight, heavy
weight, it seems like for hypertrophy, taking
it to or close to failure is what matters primarily
if you want to be guaranteed equal results which I think
is a good excuse to mix it up. No one says you need to pick just one. Switching it up every now and then can keep workouts exciting and challenging while providing a more targeted stimuli to all the different fiber types, but just remember to
listen to your own body and go off of what is
heavy and light to you. And please, don't be a Feswick. Thanks for watching, and if you're into it
consider subscribing. Until next time, D-man signing off. (lighthearted orchestral music)
