Lesson video

Hi everybody and welcome to today's lesson.

I'm Mrs. Brooks, and today we're gonna look at levers, but specifically look at those levers in action.

So that's in action within the body, but also within some sporting examples.

By the end of the lesson, you'll be able to identify and apply each lever system, but more importantly, apply them to a variety of sporting actions.

The key words for our lesson are firstly our three classes of lever.

So reminder from, a first class lever from our rhyme FLE equals one, two, three.

The fulcrum is positioned in the middle of the load and the effort.

For a second class lever, it's the load that's positioned in the middle.

And for a third class, that's the effort that is positioned in the middle.

We also need to remember about mechanical disadvantage, and know that in our third class levers, they work at a high mechanical disadvantage and they can't lift heavy loads with the same amount of effort.

So this lesson actually has four sections to it.

We're gonna talk about the levers in action as an introduction and then do a cycle on each of the class of lever and the sporting examples that work or show that lever in action.

So let's get started with those levers in action.

Quick reminder of our illustration to show that middle component.

So for our first class, we have F or the fulcrum position in the middle.

Quick reminder there in terms of how they are positioned, whether they're below or above the line.

And on our first class lever system, our effort arrow actually points downwards.

So the force is downwards in a first class lever.

For our second class we have our load in the middle, and for our third class, we have that effort and this time, that upward arrow sitting in the middle.

Now let's start looking at movements within the body that exemplify each class of lever.

So the joint movement of the neck is a really good example or demonstrates a first class lever.

So could you now actually demonstrate how it looks to head a football? And I imagine like me, most of you did that movement using your head, and moving the head forward as if you're gonna connect with the ball on the forehead part to be able to control it or move it with power.

So you can see our symbols there, or our shapes are showing, well, the neck joint, which is where the top of the vertebrae joins, that's the fulcrum or the pivot point.

The effort comes from those muscles that exist in the top of the neck.

And then the load is obviously what you're trying to move, you're trying to push that ball forwards or upwards within that game environment.

Now, a joint movement for a second class lever is actually plantar or dorsiflexion of the ankle.

Can you remember what that movement is? And could you therefore demonstrate that movement? So I'm hoping in your heads, you're all thinking about this moving onto your toes like I'm doing now, and then lowering again.

So we've got plantar flexion going up, dorsiflexion coming down.

And if we put our components on, that fulcrum when we are going to plantar flexion, you can see exists at the end of the toes.

The load is actually gravity and that's working from the centre of our body and sits in the middle, and the effort comes from that big muscle in the back of the calf, that gastrocnemius to kinda raises into that position.

And finally, a joint movement to demonstrate a third class lever is flexion of the elbow.

And I'm sure like me, you can all demonstrate that movement.

Now really key on this one to look at our shapes.

So the fulcrum is obviously our elbow joint.

Often we might have something in this arm or in this hand which would act as the load.

Now, notice two things.

The first thing is that arrow is going upwards, and even though the bicep is here in the upper arm, where it actually inserts, where it attaches to the bone that it moves is where the effort starts.

So you can see here that arrow on that diagram is really showing that insertion that the tendon of the bicep muscle that's connecting to the bones in the lower arm, so connecting to that radius.

Now, could you put them all together, like our GCSE student is doing here? So we've got FLE equals one, two, three equals NAE.

So what I encourage you to do is maybe stand up now, or you possibly could do this sitting down as well.

You're gonna practise it and you're gonna say the rhyme at the same time.

Now, when you do the movements, when you do the movements of the neck, that's when you say one.

When you go onto your toes like our students doing, that's two.

And when you do that flexion of the elbow, that's three.

And what does that remind you of? Think sport.

What can you see within those movements? Did you potentially say, so for the one, heading the ball, two, plantar flexion of the ankle, and three, flexion of the elbow.

And that's a really simple way of us remembering those sporting actions that associate with each of these class of lever.

So quick check here, which area of the body is an example of a first class lever system? I'll give you five seconds to decide.

Well done.

That is in fact the neck, because we extended our rhyme of FLE equals one, two, three equals N, A for ankle, E for elbow.

Okay, so if that's the case for our rhyme, which of these following images is the correct joint movement for a third class lever? Is it A, B or C? Yes, it is in fact B.

That's that showing that flexion of the elbow.

Now, we can see in that C that we've got, we're starting at flexion of the elbow, but what that individual is going to do is actually extend the elbow above the head.

So C would not be correct.

And we can see A there is our example of our movement at the ankle.

So nice introduction onto our first task.

Now, we can see here our student is doing a calf raise exercise.

So you can see in position E, A, sorry, the heels are on the floor and as he moves up onto his toes, that becomes position B.

We would like you to use that figure and identify the lever system that's allowing that movement.

And when you've identified it, could you draw and label correctly? Pause the recording and come back to me when you're ready.

Okay, how did you get on? I'm hoping the rhyme of FLE equals one, two, three equals NAE really helped you here to identify that, because that was a calf raise and it was taking place at the ankle, that was a second class lever system.

And drawing it, did you start with your line? Did you put your triangle underneath the line knowing that that's our fulcrum? That was the toes of that calf raise.

The load is positioned in the middle, and we said about that being gravity working or pulling from the centre of the body.

And then that effort came from the gastrocnemius in the back of the lower leg.

So there we have our second class lever system diagram.

So moving onto the second part of the lesson.

Now we know our three levers in action and we've mentioned the areas of the body where that's the case, we're gonna look specifically at sporting examples, and we'll hone in more so on the first class lever for this next part of the lesson.

We have looked at heading the ball as a really good example of a first class lever system.

For a second, we now know it's anything at the ankle.

So for example, a sprint start, you know when they're pushing off the ground or from the blocks and their ankles are very much in that plantar flexion position.

And for a third class, really simply there, we can see the athlete is doing a bicep curl.

So flexing the elbow and that's a good example of a first class lever.

We always need to be aware of our components.

So for our first class and heading the ball, we can see that fulcrum is positioned in the middle.

For the sprint start, you know, if we go up onto our toes in that plantar flexion position, the fulcrum is on the toes, then we've got the load acting in the middle and the effort coming from the back of the lower leg and the gastrocnemius.

And that's quite a nice image to show for the bicep curl.

And it really shows the effort sitting in the middle 'cause that's where the tendon, the muscle assertion of that bicep connects with the radius as they're doing that flexion and bringing that weight upwards.

So our learning is being combined here.

Just to remind ourselves for the first class lever, which of these following diagrams is correct? Is it A, B or C? Well done if you identified B is correct, because the fulcrum is positioned between the load and the effort.

Okay, so we feel quite confident now that the movement of the neck is an example of a first class lever in action.

Now, when would the neck be used in swimming? So let's talk about swimming specifically.

Can you pause the recording and think of times of when you might use the neck? It may be like this image.

You mentioned the butterfly stroke or the fly, when the neck is going up and down as part of that stroke and often when it comes up, it's to allow the swimmer to take some breath.

You may have mentioned some of the other strokes 'cause we do have the head moving to the side as well on some of our other swimming strokes.

Okay, so let's look at a different sport.

When would the neck be used in diving? A little bit trickier there.

You may have mentioned about when entering the water and being in that kind of real straight position, or potentially when they're doing those positions in the air and having to tuck the head in to help them with that rotation movement, just like we see on that diagram there.

So, why is that neck movement important in this dive? And what you could have said is it's nice and long but it's tucked in and that really helps that diver with that rotation before they enter the water.

So let's build this onto another sporting example now.

It's really good to look at different sporting actions.

So here we have a basketball athlete, and let's just point out the neck in particular, and that neck is kind of looking up at the basket, and I imagine he's looking at that so he can then be accurate with his set shot.

So we've got an example there of that first class lever system working at the neck.

And if we had to show that, we'd make sure that we draw and label our lever system correctly with the fulcrum being positioned in the middle, and that effort arrow pointing downwards.

So that leads us onto our second task where we'll just focus on that kind of flexion and extension of the neck, which we now know is a first class lever system.

We've got an example there from football of heading the ball.

But could you complete that to show examples of sporting actions from both swimming, netball and gymnastics? Pause the recording and come back to me when you're ready.

Now you could have said, and I know these aren't exclusive but there are just some examples, and what's good about these is they're very specific examples, right? So for gymnastics, they haven't just said the forward roll.

What's been said there is actually pointing that action which is specific to the neck.

So where you took that head in, as you're gonna do that forward roll, we know that's really part of effective technique to allow that role to happen and also keep the neck safe.

For swimming, we'd already looked at that head movement in the butterfly, and it could be that netball, like our basketball athlete, you are just having to position your neck 'cause you're often watching the ball before taking in that catch.

So it's allowed that head movement to be accurate with your technique.

So let's now look at those second class lever sporting examples.

We've already done, but it won't hurt to remind ourselves 'cause this allows this topic to be really memorable and easy to recall.

So FLE equals one, two, three.

So we know the position of the component that's in the middle, whether it be a first or second or a third.

But now we've added in that, well, first is for neck, we're moving on to second now which is at the ankle, and that third is then at the elbow or the knee.

So looking at these images carefully and the joint has been identified for us on these images, which of those actions are clear examples of a second class lever? Really well done if you used our rhyme there and saw that both A and C are actions of a second class lever 'cause it's identified as the ankle.

So we can see that push off from the sprint start, and also that push off from that skater movement which individuals will do to develop power, particularly in those leg muscles.

So can we think of any other examples of the ankle in action? I suspect there are loads that you could think of here.

So as we pointed out on that task we've already done, we used the calf raise as an example of a second class lever.

And we know that this action looks very much like the image there.

It's going onto the toes and it's those muscles in the back of the calf, which we refer to as our gastrocnemius, going into a position of contraction, so that they can push the body up and go onto the toes or plantar flexion.

Now what sporting examples can you think of where that movement, that exact movement of going onto the toes or the toes being pointed is used? There is a real variety with this, and just some examples you could have said there is that takeoff as you hit the board in the long jump and you go up onto your toe as you propel yourself into the air.

It could be simply those sports where it really is assessed on how it looks.

So often, we'll see extension of the leg but also the toe's being pointed.

Or it could be taking off on both feet.

And a good example of that is jumping to block the ball in volleyball, you'll basically go into plantar flexion of both ankles to allow you to explode upwards and and execute that action.

So Andeep is asking the question here, "Which lever system is working at the ankle during a high jump takeoff?" And the bit that really should jump out to us is that part about the ankle, the area of the body that we now know is associated with that second class lever system.

And if we were to draw that, we'd do it correctly by positioning the load in the middle of the effort and the fulcrum.

If we were asked to describe that, we'd link it to the sporting action that's been asked, so the high jump takeoff, and then link it to the sporting movement of plantar and dorsiflexion, and knowing that because those movements occur at the ankle, that is an action or an example of a second class lever system.

So from this, we can develop our table or our notes from the previous task, and now look at those four sports again, swimming, netball, gymnastics and football, and now put in examples of a second class lever system.

So things that are happening, actions that occur at the ankle in those four sports.

Pause the recording and come back to me when you're ready.

Again, these are not the only right answers, but what they do provide is some clear examples where the writing is very specific, okay.

So it's the flutter kick in swimming, it's jumping for the rebound, running towards the vault, shooting the ball but talking about actually striking the ball with an area of the foot in football.

So we wanna try and make our examples are as specific as they can be.

And last but not least, following that similar kind of theme, we'll now look at those sporting examples that are specific to a third class lever system.

So let's start with this action.

We can see here this athlete is about to strike the football, and Aisha is asking, "What would be the next stage to this sporting action?" So if you had to picture that in your mind, how would that look? Now, we would probably tell Aisha it looks something like this.

So we can see in that position A, that action is very much the prepared or the starting point of kicking the ball, and we'll now refer to that as position A.

And then as the athlete has extended that knee and actually made contact with the football, so she's executed the movement, we've got position B.

And sometimes dividing the sporting action into its parts helps us understand that lever system in action.

So we see here we've got the knee joint in a position of flexion, and as it's gone through to that position B or that execution image, we've got a position of extension.

Now, if we were then to link our lever systems, which is the correct component for the knee joint when kicking a football? Is it the lever, the load, the effort or the fulcrum? Five seconds to decide.

Well done.

It is in fact the fulcrum, and that would be the shape of a triangle, and it's that pivot point that's occurring for that movement.

Now, this is a really good example because it's at the knee, this is an example of a third class lever system.

So let's just remind ourself where those components are.

So yes, the knee joint is the fulcrum.

The effort comes from that muscle insertion, remember.

So our muscles at the top of the thigh, those quadriceps, they will be attached to the tibia and that's the bone that that muscle moves or that muscle group moves.

So that effort very much starts at that muscle insertion.

So we can see there that's just offset from the actual joint, and that becomes our effort and it's an upward arrow.

And the load in this instance is the football.

That is what that athlete is trying to move.

So if we see this again quite clearly, just to make sure we are happy with why the effort is positioned in the middle.

There's our fulcrum, the joint, our load is the football, and they're actually from opposite ends of each other.

And then the effort here is coming from that muscle insertion of our quadriceps.

So again, the effort is on the top of the line and that's pointing upwards to represent the force and the effort that comes from the quadriceps and starts at the insertion in this particular movement.

Now this is a good point to talk about mechanical disadvantage.

So we can see that same diagram there on the slide.

Can you remember what those two arrows represent? So there's been two additional components added to our diagram.

Well done if you remembered that one of those components is the effort arm.

So we can see that that's the distance from the fulcrum to the effort.

And the other component, the slightly longer one is the load arm, and that's the distance from the fulcrum to the load.

Now, as I just acknowledged there, the effort arm is shorter than the load arm.

So we can see in a third class lever system, the force required is much larger to be able to move a load, and this is known as mechanical disadvantage.

So for our footballer, that joint is working at a disadvantage due to the position of the components, and hence why a lot of footballers, and this goes for a lot of sports, they strengthen their muscles, and often that is to kind of support the fact that those levers are working at a slight disadvantage.

Now, was the effort arrow, when kicking a football, was it drawn as a downward arrow or as an upward arrow? It's important that we get that right for that effort component.

Is that true or false? Absolutely, that is false.

And in the third class lever, the arrow points upwards and sits on the top of the lever line.

Whereas in the first class lever is the example of a lever where it points downwards.

Remember our podium, if they're on first place, the only way you can really go is down, but if you're in second or third, there is that opportunity to go up.

And that might be just a really simple way of remembering which way the arrow is positioned when we look at these diagrams or look at these levers.

Okay, so we've looked at the knee joint, let's now be specific to the elbow joint, and we'll look at that in a biceps curl.

We can see, like our footballer, we've got position A to position B.

So that preparation part then move into that execution or lifting the dumbbells towards the shoulders.

I would like you to identify the class of lever that is operating during that movement, then draw and label that lever system correctly, and using the understanding of mechanical disadvantage, describe how the lever system is operating during this movement.

And to help us with our breadth of examples, could you identify three other sporting actions when that lever is in use? Four questions there on the biceps curl.

Pause the recording and come back to me when you're ready.

Okay, so during that upward phase that preparation to execution, the third class lever is being used.

So in drawing that, we would've had our fulcrum at the end of the lever, the load which would be the dumbbell, and then the effort coming from the insertion of our bicep muscle.

So that's connection from the biceps to the radius.

So we have there a correct drawing of a third class lever system.

If we had to make those descriptions, we could build on some of that knowledge I've just shared there.

The load is the weight, the fulcrum is the hinge joint.

That effort is that insertion and that's that tendon attached to the radius.

And when that bicep contracts, it applies that effort to pull the bone and move the weight upwards.

Now if we're gonna link that to mechanical disadvantage, the effort arm is much shorter than the load arm.

So hence why a lot of people will strengthen that bicep muscle if they want to be able to lift a larger load.

And for identifying some other sporting examples or actions, these are just some different examples.

Chest pass at the elbow, rowing action at the elbow and the knee, knowing they bend and straight as they move their oars.

Or it could be simply doing a punch and how that will have flexion, but also extension at the elbow.

You could have picked others.

What I hope you did pick is examples of actions that take place at the knee or the elbow.

So let's summarise for our levers in action.

A first class lever is neck flexion and extension, and we gave that sporting action of a head-in in football.

We then, we built on that and looked at other examples of the neck.

For a second class lever, we went up onto our toes and then came back down again.

So recognising the plantar and dorsiflexion at the ankle are examples of a second class lever system.

And there are many times in sport when the ankle is used.

The sprint start is a good example of that.

And then a third class lever, we were looking at flexion of the elbow and extension of the knee, and we gave that kind of striking of a football as a really good example of that extension of the knee.

That did develop into that understanding that mechanical disadvantage does occur within those third class lever systems. Thank you so much for joining me today, and I look forward to seeing you on the next lesson.