Lesson video

Hello, and welcome to today's lesson.

I'm Mrs. Brooks, and I'm gonna be taking you the through the lesson of levers and building on our learning of the components of levers, but specifically within sporting actions.

This forms part of the movement analysis unit, the specification.

We're gonna have lots of fun, and no doubt, you guys are gonna do brilliantly.

By the end of the lesson, we will not only be able to identify the lever systems or develop our confidence with identifying those lever systems, but more importantly, be able to apply each of those systems to a variety of sporting actions.

Our key words for the lesson, we probably recognise three of them 'cause there are three classes of lever.

Let's just remind ourself that that first-class lever is where the fulcrum is positioned in the middle of the load and the effort.

Our second-class is where the load is positioned in the middle.

And finally our third-class is when we have effort positioned in the middle.

A word that we're going to introduce as we move through the lesson is mechanical advantage.

And we just need to know at this stage that that is when we're referencing the efficiency of a working lever, i.

e.

, how efficient it is in able to move the load or the resistance.

And we need to know that the calculation of that is where the effort arm is divided by the resistance arm.

More of that as we move through the lesson.

Our first lesson, first part of the learning, though, is where we're going to look specifically at the first and second-class lever and look at sporting examples and sporting actions for those two types of lever.

Okay, let's just have a quick recap on those three lever classifications and remind ourselves that our FLE equals one, two, three is a really memorable and easy, simple way to know which lever was which, depending on what was in the middle or which component, should I say, is in the middle.

So remember the first-class, we learned that the fulcrum, the F is positioned in the middle.

For our second-class, that changes to the load, FL.

And then for the third-class, we see the effort positioned in the middle, FLE equals one, two, three.

Now, we need to build on that learning and start to really kind of consider some of those sporting actions where those levers are being used.

And previously, we knew that that overhead tricep extension was an example of a first-class lever system.

So we can see here this athlete is doing exactly that, a little bit like what I'm doing now, using the weight and just lifting it above the head.

And those triceps are working really hard there to extend the elbow.

Don't know if you remember, but for our second class, we did a lot of going onto our toes and that plantar flexion, P for plantar, P for point and talked about that work at the ankle.

And look here, we've got exactly that in that image.

We've got an athlete there that is in that, kind of, sprint start section of a sprint race and really pushing off from the ground or from the blocks specifically at the ankle.

And finally for our third class, we talked about that flexion of the elbow.

And that could be really simply just referring that, referencing that, sorry, as a bicep curl.

So we can see here that that individual has got those dumbbells at the start and then just curls them or flexes the elbow towards the shoulders and the chest.

Okay, now if we need to look at the placement of those components, we could hopefully show this diagram.

So this is now that athlete but stripped back, and we can just see the arm, the bones and the joint within the arm, and that tricep muscle at the back of the upper arm.

And hopefully you can see on that the fulcrum is our joint or our pivot point.

The load would be the weight that the athlete was trying to lift, and the effort, that force going downwards, quick reminder there about that downwards arrow in the first-class lever system.

We can see here how that operates in the plantar flexion.

Notice there that that's a showing an arrow for the load, but we all know that should be a square.

But it does show our effort arrow moving upwards, which is coming from that gastrocnemius, that muscle in the back of the lower leg.

Key thing there is really it's the ankle.

Anything the ankle, we reference as a second-class lever system.

And what a lovely drawing there of our third-class bicep curl, specifically that effort arrow going upwards.

And let's look at that bicep muscle and where it's connected to our radius bone.

Can we remember what that was called? Don't worry if we can't because that's known as a muscle insertion.

So it's where the tendon of that muscle is connected to that bone that that muscle will move.

So the fulcrum becomes the joint.

The effort starts at that muscle insertion.

And then the load becomes that weight that that arm is trying to curl.

Okay, let's have a quick check at this point with some of that learning.

We've got our three diagrams here, but we're asking you to pick the one that is correct for a first-class lever system.

I'll give you five seconds to decide.

Well done if you identified B.

I'm hoping what you did in your head is FLE equals one, two, three.

The F and the one go together, so that reminded you that the fulcrum is positioned in the middle, so therefore, B was the correct option.

A has got F in the middle, so that's our third-class, whereas C has got load in the middle, and that's our second-class.

This slide is just a really nice reminder, as well in terms of those components, where they sit below and above the line and particularly a bit of a reminder of our downward arrow for a first and an upward arrow for a second and a third-class lever.

Okay, let's look at our actions, our second checkpoint.

Which of these three images do we remember were particularly a good example of a second-class lever? Well done if you pointed or you identified option A 'cause that's showing the ankle being used in a sprint start action, whereas the other two are looking specifically at the elbow joint, whether that be a third or a first-class lever.

Okay, so we know now or we're feeling pretty confident that for that first-class lever, we've got this triceps or this overhead extension.

Now, let's start and think about this more within sporting situations.

Look at that picture there.

We can almost see the exact same thing happening.

The rugby player has the ball above their head, just like they would do in a line out, and they're gonna then throw that as straight as they can 'cause that's what the rules say into their own team, who's gonna hopefully try and take it out the air and then keep possession of the ball.

So we refer to that as a line out.

Can you think of any other examples where that movement is being used? Pause the recording and have a write some of those down or have a chat with the person next to you.

What did you come up with? I suspect you may have said things like a throwing in football, an overhead pass in netball, a set shot in basketball, an overhead clear or smash in badminton.

There are so many different sporting actions where really that movement is that one of tricep extension.

Throwing a javelin, okay.

A shot put, pushing it forward and trying to push it as far as possible.

Okay, a calf raise for our second-class lever.

We spoke about the ankle.

What does that action look like? Maybe as you sat down now, you're all doing this, and you're all going onto your toes, a bit like I'm doing, exactly that, just like that image is doing, that individual is just moving onto their toes.

What about sporting examples for this movement? What can you think of? Okay, these are just examples you could have said.

Don't worry if they're not these ones 'cause there are lots and lots and lots of different actions within sport where the ankle either goes up onto the toes or back down that kind of plantar and dorsiflexion movement.

Just for example there, we've got maybe that takeoff when you're gonna jump into the long jump pit, pointing your toes, which is really common in, like, gymnastics and dance and trampolining 'cause they get very much judged on how they look.

So having that nice pointed toe shows that extension particularly of the leg in those kind of movements.

It could be that you're jumping off the floor in volleyball to jump as high as you can to block the ball and try and prevent a point being scored.

Lots and lots of different examples of when the ankle is being used.

So Andeep is saying, okay, we were mentioning takeoff, so I wanna think specifically about the high jump within athletics.

And he's then saying, well, what lever system is that? Now, we've got an image there of what that high jump takeoff looks like.

We can see the athlete running on a kind of a curved approach towards the bar and then pushes off the floor and rotates that body to try and clear the bar, arch the back and get as high as they can over that bar.

But Andeep is asking specifically about the ankle, and questions will always do that for us.

They'll always ask us to talk about the specific joint so we know that point becomes the fulcrum, the pivot point or the triangle.

Now, the key in this for Andeep is to tell him that, actually, it's a second-class lever system because it's occurring at the ankle.

Anything at the ankle is second-class.

And we can see there, I mean, the athlete has kind of pointed or pushed off the floor, and we've got that plantar flexion, and that is a example of that second-class lever.

A little bit of reminder there on the slide about how that would be drawn if you were asked to draw that and, you know, those four components that we're hopefully really confident with now.

Now, this athlete is our basketball player, and we can see he is just about to do a set shot or push the ball up towards the basket to try and score.

Again, the arrow is showing that this, we want to think specifically about the elbow joint, and I'm hoping you are all saying, okay, we get that this is our triceps extension, this movement above our head, and therefore, that's the first-class lever system.

Let me just remind you, you might even wanna pause the recording and do it yourself, our rhyme, FLE equals one, two, three.

So as I said one there, we've got this movement that is really similar to the movement that that athlete's going to do now to push that ball into the air.

So therefore, that is an example of a first-class lever system, and we would know that our fulcrum, for that reason, would be positioned in the middle of a diagram.

So now we've looked at some examples of first and second-class lever.

I want you to do this quick first task.

It shouldn't take you too long, but we've got four sports listed on the left there, and we've got two columns, one that's up for a first-class lever, so this movement, and the other which is that movement at the ankle.

And I want you to think of some actions from that sport that would be representative of either of those two movements.

It might be that you want to change those sports and do your own sports, but for the minute, we're gonna look at rugby, netball, football, and cricket.

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

Okay, how did you all do? For rugby, it might be that we'd already been given our line up throw, and we'd seen an image of that, but maybe for the second class, you spoke about when that ankle was in use.

So an example on the screen there is that pushing that we see specifically in that lower body when the players are pushing in the scrum.

Don't worry if you didn't write that.

You could have come up with different options, maybe when they're running and sprinting with the ball.

Okay, anything really at the ankle.

Netball, in this instance, we went with that overhead pass as an example.

I imagine some of you might have done the shooting technique.

And then for that ankle, being able to jump at the rebound.

Maybe you talked about dodging and, you know, transferring the weight from one side of the ankle to the other, being up on the toes, ready to run towards a ball and catch it.

Likewise for a football, it could be that you talked about the throwing or the goalkeeper when they start with the ball here and they throw it overhand to get it as far as they can to a player that might be making a quick break.

And then they're doing a lot of work with that plantar and dorsiflexion, particularly as footballers when they're striking the ball with the ankle or where they're running towards the ball.

And finally cricket.

When the fielder has to pick it up and throw it really quickly, they often choose to do an over-arm throw 'cause they can get more power and more distance.

And that's the same isn't it? It's that overhand extension.

And then when they're batting, they often, if they're stepping forward to attack it or maybe even defend the shot to stop the ball hitting the wickets, they're moving onto that ankle, and that we see an example there of dorsiflexion.

So now we've looked at our first and second-class lever examples, we need to look specifically at the third.

I'm gonna talk about this a little bit separately on purpose because we've already established that sometimes that can feel a little bit confusing because of where the muscle insertion is.

What we do know though is the effort from our FLE equals one, two, three is in the position in the middle of a lever diagram.

So here we have an athlete, she's just about to kick the ball.

So Aisha's saying, okay, so if we were to show this as another image, what would be the next stage to this action? And that's the right thing for Aisha to ask because it's so common when we get questions like this that we are shown two movements and often reference them as position A to B.

So we can see here that B image is exactly that next part of the action.

As the athlete or that footballer has come through to kick the ball, she's extended the knee and the leg 'cause she's trying to get as much power on it as possible.

It probably looks like she's maybe even making a shot on goal to try and score the goal.

Now, again, our arrows show us that we would probably be specifying a joint.

So at this point, I want us to focus specifically on the knee, not the hip, not the ankle, but we're gonna look at the knee.

Now, if we're thinking about the knee joint, let's just do a quick checkpoint.

What would be the correct lever component that would represent the knee joint when kicking a football? I'll give you five seconds to decide.

Absolutely, that would be our fulcrum, our pivot point, hopefully you're all shouting at the screen, representing a triangle.

All right, now we are using this movement 'cause it's an example of a third-class lever system.

Now, with our FLE equals one, sorry, one, two, three, we looked specifically at a bicep curl, and we're gonna extend that now and talk about another example of a third-class lever system, and we're gonna use kicking a ball as that example.

So let's understand how that becomes third-class.

We've already identified in our checkpoint that the knee joint becomes the fulcrum, the pivot point.

That's where that kind of flexion and extension is taking place.

And we know that we would have to label that as F for fulcrum, or better still, actually write fulcrum.

Now, the effort, in fact, let's see the load first.

So we know the load is the ball.

That's the resistance that we're trying to move to move it as quickly as we can and try and score a goal.

But that effort is key for us to look at.

We can see already on the diagram, it's sitting in the middle.

So we know whenever the effort is in the middle, that is a third-class lever.

Let me show it you in this way.

So there's our fulcrum, the knee joint, there's our load, the football, here's our effort.

Now just look under the line there where that's trying to help us.

That is where our quadricep muscle, that big group of muscles that are on the front of our thigh, they are responsible for moving the tibia and the fibula.

All right, so the insertion, the tendon actually connects to the tibia.

In fact, if you were to run your hand all the way down now, the quadricep over the knee, that area there is kind of where that muscle tendon is, right? And that's where the effort starts in a third-class lever.

Sorry, that's where the effort starts when we're kicking this football, so therefore, it becomes a third-class lever system 'cause it's just the side of the fulcrum.

But more importantly, it then becomes in the middle of the other two components.

Okay, let's just make sure we feel happy with this.

So a quick checkpoint, true or false, the effort component when kicking a football will be drawn as a downwards arrow.

So think back to that diagram we've just reviewed together.

Is that true or false? Yes.

Well done.

That's actually false, and that's good for us just to kind of keep reminding ourselves.

In a third-class lever system, the arrow points upwards on top of the line.

It is in the first-class lever where it points downwards.

I believe you may have done some learning around using a podium, a metal podium as an example.

So if you're in first position with that gold medal, you can only go downwards.

So first position, arrow goes down.

However, if you're in that second or third that silver or that bronze medal, there is a way of you maybe going upwards.

If you were to do that again, you could finish in a higher position, so you would go upwards.

So the arrow would be pointed upwards for our second and third-class lever, which is probably quite a nice way of linking us into our second task.

We've spoke about kicking a football, but in our FLE equals one, two, three, we knew that the biceps curl was an example of a third-class lever.

So here we have it drawn in the same way in terms of the two positions, A to B.

And we're being asked to, firstly, identify that class of lever and then draw it and label it correctly.

Once you've done that, could you give a really brief description to then show that you understand why that is a third-class lever? Pause the recording and come back to me when you're ready.

Okay, so in our upward phase of a bicep curl, or biceps curl, sorry, did we recognise that that was a third-class lever? I'm hoping we did from our nice rhyme and dance.

We, therefore, will have drawn it in this way with the effort positioned in the middle, also the effort pointing upwards.

And then we would make sure that that would be labelled 'cause it's very common that we not only get asked to draw it but get asked to label it as well.

Now, the final part of that task though was to use some of our descriptive language so we show that we understand how that is a third-class lever for our biceps curl.

And I'm hoping that you may have done some description on the load is the weight, so that's why it's on the end.

The fulcrum is the hinge joint in the elbow.

It's good to know those different types of joints.

And then the effort comes from that insertion, that tendon that connects from the biceps muscle to the radius.

And therefore, when that contracts, the effort starts there and will pull that up towards the chest.

It will pull that weight upwards.

Well done on task B.

And we're now gonna finish our last little bit of our learning where we're gonna talk specifically around mechanical advantage.

Now, when we looked at our keywords, I shared with you that mechanical advantage is looking at the efficiency of a lever, so whether it has got advantage or it actually works at a disadvantage.

Now, on our diagrams, many of which we've drawn now to really develop that confidence about drawing those components, when it comes to talking about mechanical advantage, you are expected or we hope that you are able to apply two additional components.

Now, those components are arrows, and we refer to them as arms. So one of them is an effort arm.

And don't worry about this 'cause it all it is is just you drawing a line or an arrow to show that this is a part of the lever that runs from the fulcrum to the effort.

The other component also starts at the fulcrum, but it runs from the fulcrum to the load, okay? So effort arm, fulcrum to effort.

Resistance arm, fulcrum to load.

They're the two additional lines that you may be asked to add to a lever diagram, and they're quite useful for us to understand mechanical advantage.

So let's just remind ourselves of a second-class lever system.

Straight away, FLE, our L was in the middle, and it linked with two.

So the load is in the middle of this diagram.

And on either side of that, we've got our fulcrum and our effort.

Now, just watch carefully now in terms of those two additional lines or components.

This first one here is the effort arm because it's the distance from the fulcrum to the effort.

The opposite of that is the resistance arm, which is the distance from the fulcrum to the load.

Now, review that diagram.

Take a look at it.

Say what you see.

What do you notice about that effort and resistance arm? Don't overthink it.

Don't think it's too complex.

Speak to the person next to you and say what is the obvious difference.

And I hope you all then did say to each other, the F arm is longer than the resistance arm.

That's really clear for us to see in those two arrows.

And that is quite beneficial for a second-class lever system 'cause that then says that, as a lever system, it has high mechanical advantage because the F arm is longer than the resistance arm.

Okay, this is the first time we've learned about these two components.

Let's just have a quick checkpoint to make sure we understand.

The effort arm is the distance between the load and the effort.

Do we think this is true or false? Absolutely, well done if you recognise that this was false, why? The two arms, the two components always start at the fulcrum.

All right, so the effort arm is the distance between the fulcrum and the effort, not the load and the effort.

So that's important that we know that they both start at the fulcrum.

Now, if we were to calculate mechanical advantage, what we would be asked to do is we'd be asked to divide the effort arm over the resistance arm.

At this stage, it's just important that you know that this is the calculation and that difference between the effort and the resistance arm will determine whether we it is at high mechanical advantage or low mechanical advantage.

But we pointed out, didn't we, when we looked at our second-class lever, we knew that the effort arm was longer.

So that's a good thing.

That high mechanical advantage means that those large loads can be moved with relatively low effort.

So can you remember our wheelbarrow? Let's just go back, and we spoke about how we had the wheel as the fulcrum, all that effort, sorry, all that rubble and mud and things that might need to be cleared sitting in the middle.

And that is then the load, and the effort came from someone who would be holding the end of the wheelbarrow and using that effort and that force to move it where it needs to go.

Well this is kind of why the wheelbarrow was designed in the way that it was 'cause it's about moving large loads with relatively low effort, and that's because that effort arm is longer.

That distance between the wheel and the person that's lifting it is longer than the actual resistance arm, which is the load, the bit in the middle and how that close that is to the wheel.

So key thing there is just to know that a second-class lever system operates at high mechanical advantage.

Think back to our ankle.

Our ankles have to work really hard most of the day 'cause they're carrying their body weight.

You know, they're carrying our body weight with whatever we do.

So therefore it's useful that they do work at high mechanical advantage so they're able to carry our body weight with relatively low effort.

Okay, so it is always good to remind ourselves of our drawings.

One of these is a lever that represents high mechanical advantage.

Five seconds to decide which one you think that is.

Absolutely, that's option B.

And hopefully, you picked option B 'cause we've got a diagram there of a second-class lever system.

The load is positioned in the middle of the fulcrum and the effort, which takes us onto our final task.

Only, now, we are gonna look at a first-class lever.

So the first thing I would like you to do is draw that first-class lever system.

Use your FLE equals one, two, three to help you.

Only now, we're gonna take it that next step like we did with the second-class.

And I'd like you to add on an effort and a resistance arm to that same diagram.

Once you've done that, you're now gonna then say, well, why has that lever got low mechanical advantage? And if we can apply that to a sporting situation, imagine that was a netballer doing the overhead pass.

We spoke about that earlier on the lesson how that's an example of a first-class lever system.

What's the impact of that low mechanical advantage? Pause the recording and come back to me when you're ready.

Okay, how did we get on with this task? Hopefully, you are looking at the slide there and thinking that is a really similar diagram to what you've drawn for your first-class lever.

The effort, fulcrum, and load are now labelled.

Just a quick note that the fulcrum is positioned in the middle, and the effort is pointing downwards.

Now, your next part of the task was to then add the effort and the resistance arm.

So hopefully, your first one that you drew was the distance between the fulcrum and the effort.

And then the next one that you drew was the fulcrum to the load.

And that's our resistance arm.

Remember, this is us talking about an overhead pass in netball.

So if you've drawn yours a bit more like a seesaw, that's okay, but you may just want to move your fulcrum a bit closer to the effort, 'cause look how close they are to each other when we're doing this movement here for overhead pass.

Now, what do we see from that? Why is there a low mechanical advantage? Hopefully, you guys just stated quite clearly, well, the effort arm is now shorter than the resistance arm.

That had been quite the opposite with our second-class lever.

And the impact of that for someone that is executing that overhead pass is it is gonna mean that there's gonna be more effort needed, particularly from that triceps muscle, in order to generate the force required to make sure that pass is not intercepted.

Now, that was quite the difference to our ankle or our wheelbarrow example 'cause we were saying that there's not as much effort needed to be able to move those large loads.

So what we've learned there is the first-class lever system, and it's true of the third-class as well, they operate at low mechanical advantage.

Okay, lots to summarise there, but let's just revisit some of our, well, all of our key learning points for this lesson.

Those sporting actions, first-class lever, overhead triceps extension.

Second-class, anything at the ankle, that's me on my toes, doing that movement or going onto a plantar flexion of my ankle.

Third, we looked at that flexion at the elbow, but we even extended that to look at our footballer and look at that extension of the knee.

We then now know that a lever can be given two additional parts, an effort arm, distance from the fulcrum to the effort, and a resistance arm, distance from the fulcrum to the load.

That allows us to work out or calculate mechanical advantage, and it's specifically high in a second-class lever.

So that is our efficient lever, as we have small amounts of effort required in order to move those large loads.

And just a reminder there of that calculation for mechanical advantage is effort arm divided by resistance arm.

I have really loved working with you today.

Hope that's been really useful to kind of be able to analyse those three classes of lever to the sporting actions, and I look forward to working with you on the next lesson.