Hey guys!!! It's JP Gloria and this time, we're going to look at how form
changes in elite runners as they run faster..
specifically with long-distance runners! I will illustrate this through utilizing the
running clips on Mo Farah, an long-distance runner, of when he
completed the 5k in under 13 minutes! During this specific race, I was able to
get 2 good side views of him running, during approximately 2/3 into the race,
at a pace of two minutes and 36 seconds per kilometer... and then him sprinting
toward the finish line at around 2 minutes and 6 seconds per kilometer pace!
Using these clips, I will point out a few common changes elite runners do as they
run faster! Now these changes may vary to some degree across all runners, but
hopefully, this will provide useful information to improve the way you run!
First, let's talk about two overall factors that ultimately make up a
runner's velocity, which are stride length and stride frequency. Starting with
stride length, people tend to overemphasize this. When one initially
sees that increased stride length increases running speed, they may think
to bring their foot out more to increase stride length, but this is a common
misconception as this may actually slow you down, but I'll talk about this in
detail later in the video. Anyway back to comparing Mo as he sprints, if you look
closely, the foot position relative to the body does slightly go out more, but
not by much... So where does the increase in stride length mostly come from??? Well
first, let's see how far the body itself actually moves. When comparing the
distance traveled, you can see more of a difference. By using this object here as
a reference point, this can help you see that difference in step length in both
clips. It's not as far as it actually seems as during this clip
where he sprint, the foot starts off a bit farther away from the object; however,
even if you deduct that extra distance... you can still tell that he still covers
more ground with one step! Therefore, the increases in stride length is actually
more of a product of increased force generation through the legs. To sum this
all up for you... while positioning of the foot
relative the body does not change much, the increased power of the legs from the
athlete allows him to propel farther forward, which is the REAL contributing
factor to increased stride length when running at higher speeds. Now, the second
part of the equation is stride frequency. If you compare these clips, you can see
that Mo takes steps more quickly when running at faster speeds. Increasing
stride frequency or cadence, which simply means steps per minute, is something that
most commonly occurs when we run faster. Actually increasing cadence not only
helps with speed, but it may also decrease risk in running injury. Based
on a systematic review, looking at the influence of stride frequency and length
on running mechanics, findings suggest that increased cadence may decrease
vertical excursion... aka excessive bouncing during running, impact shock, and
ground reaction force... as well as increased energy absorbed in the hips
knees and ankles. Now even though there is evidence on this, I don't want you
guys to solely focus on increasing cadence, maybe try to incorporate a
slight increase in cadence and see how that impacts the way you run. If it feels
right, then, that's great for you! If it feels very uncomfortable, maybe
increasing cadence isn't the factor you should be working on at the moment. Now
that we covered that... let's get into looking at specific parts of the body and
what changes as elite athletes run faster. To really support some of this,
the IAAF just recently published biomechanical studies that contains
information on the joint angular data for the top eight athletes during
certain races from the World Championships in London 2017. In this
case, here are the angular differences from the 10k and marathon races in those
studies. It's pretty interesting stuff and if you're a nerd like me you can
totally check it out yourself... I'll leave a link in the description below!... Anyway
let's start at changes seen from the lower part of the body and work our way
up! We will start at the foot... specifically positioning at the foot as
it lands in relationship to the hips! As I mentioned in my previous analysis on
Mo Farah, during this clip at a slower pace, this foot lands pretty much right
in front of the hips. However, there is a difference in landing as you
move quicker speeds. As you can see from this research study comparing joint angles
in a 10k and marathon... as well as when Mo sprints in this race, foot landing
tends to be a little more forward in relation to the hips. During faster
paces, this may initially look like over-striding,
as common knowledge and running is for the foot to land under the hips; however
one need to understand why people are taught to land under their hips in the
first place. The reason this is taught is because that is where our center of mass
usually is when we are standing. Now, when you are running, the center of mass
shifts forward. This weight shift forward actually increases even more at faster
speeds!! This is also why it is much hard to stop yourself from when you are
running very quickly as to actually stop... you need to shift your body weight
backwards even more. Since Mo is running at a quicker speed in this clip, the
center of mass is more forward. Therefore, even though Mo's foot is landing farther
out from the body, you still may be landing right around his center of mass,
which is where you want to land for optimal stride length. How to incorporate
this into your running is you usually to let this happen a bit more naturally.
People usually get caught up with the type of foot landing whether it's the
heel mid foot or fore foot and they try to force this kind of landing, which is
not always the best thing to do. Now, Ta land under the center of mass, don't
focus on whether it's heel strike forefoot or whatever... let that specific
part just naturally happen and just be more aware of where the foot lands in
relationship to the body. You might need to practice this in the mirror to gain
awareness of the position. Then when you start running... a good reference point is
to start with the foot landing under the hips and modify this landing based on
what feels right for you during that specific running pace. Looking back at
the comparison of angular motion between the slower pace seen in the marathon and
the faster pace seen in the 10k, you can see that there was a slight difference
in knee drive. Though not as much, if you look closely, you can see the slight increase
in knee flexion as Mo drives the knee forward when sprinting as well. As I
mentioned in previous videos, this allows for improved cyclic motion to occur for
efficient pathing of the foot as it progresses forward as well as
utilization of elastic properties of the leg muscles.
Now some of the reason this occurs at higher speeds is because of increased
tension in the quads and hip flexors as well as increased force generation
coming through the legs as it transitions to swing phase. Increased
flexion in the knees as it swings forward, also can cause a slight increase
in step length; however as I noted before, you don't want too much increase of step
length where the foot is too far forward... otherwise it's known as over-striding.
This is why while knee drive is good to incorporate into your form, too much of
it can cause over striding which can actually cause a braking mechanism to
occur to slow down your running. A good way to practice optimal knee
drive is to practice running over mini hurdles or small objects. You can usually
start with objects that go up to around mid shin to about 2/3 up the shin and progress
the height a little bit as long as it does not feel too uncomfortable to do so
when going at quicker paces... just remember what I said about too much
knee drive. The last thing I'll mention about in this video is arm swing. The magnitude
of arm swing, aka pumping of the arms is usually increased at higher speeds. You
can kind of see this when looking at the angular differences in these studies as
the shoulders extends slightly more on average during the 10k study. This is
kind of shown in Mo Farah's running at different paces as well, but clearly not
as much. One of the reasons this occurs is to use the arm swing to counteract
the rotational forces coming from the legs as it pushes against the ground.
This is why as one leg swings forward, the opposite arm swings forward as well.
As I noted in the beginning of the video... when running at faster speeds, increased
force generation occurs at the legs. To accommodate for this, increased pumping
of the arms is used to counteract this increase in force. Without doing so, this
may cause an increase in side-to-side movement, which can make it difficult to
maintain a straight path when running. Now, with arm swing, the body usually
takes care of most of the work... just keep your arm movement relatively close to
your body and let you and your body figure out how to adjust how much
movement it will need to counter rotation from the legs!!! ...And those are
just a few ways on how elite long distance runners change their form as
they go faster! I definitely want a bit more in depth in this video compared to
others. However, there are plenty of other things
that usually change as they run faster as well. Maybe I'll make another video in
the future to address these things! Anyway, I hope you guys learned a few
things from this video to improve the way you run. I love all the support you
guys have given me. For those who enjoyed the video and want to see more please
subscribe to my channel! Also feel free to comment on what other videos you
would like to see. I listen to all your suggestions. And as always.. THANK YOU FOR
WATCHING!!!