Lesson video

Hello and welcome to today's lesson.

My name is Mr. Sweis, and thanks for joining me again today.

We're going to be looking at aerobic and anaerobic exercise to better understand the difference and some practical examples of each.

You may have come across these terms before when perhaps doing some running events in athletics or during fitness training, or maybe even in a science lesson where they talk about aerobic and anaerobic respiration.

Today's lesson is called Practical Examples of Aerobic and Anaerobic Exercise, and it comes from the Anatomy and Physiology: Anaerobic and Aerobic Exercise unit.

By the end of this lesson, you'll be able to apply your knowledge of aerobic and anaerobic exercise to various sporting examples.

So, before we get started, can you think what the difference is between aerobic and anaerobic and can you think of any examples of physical activities that rely on aerobic respiration versus other activities that rely on anaerobic respiration? The key words for today's lesson are aerobic exercise, anaerobic exercise, and lactic acid.

You may want to pause the video to make a note of them, but I'll explain them fully as we go through the lesson.

Okay, so I've broken up today's lesson into two parts.

The first part will be the basics around the difference between aerobic and anaerobic exercise.

And then into the second part, we'll look at some specific examples of aerobic and anaerobic exercise in action, and in fact sometimes activities involve a mixture of those two different types of exercise.

Okay, so we know, don't we, that our bodies need energy.

And when we exercise, even more energy is required to get supplied to your working muscles to enable those muscular contractions to happen.

So we know that we need to somehow get energy to our working muscles so that when they're gonna be creating contractions to do exercise, or movement, or play sports, then that extra energy has been provided.

Well, digging a bit deeper into this, it's important to know that that energy comes from the food that we eat, in its simplest form as a thing called glucose or glycogen, and then also from the air that we breathe, or more specifically the oxygen in the air that we breathe.

And those two compounds working together, glucose or glycogen and oxygen, are what provides that energy for exercise.

And depending on how hard or intensively we are exercising, that energy will then be provided either aerobically or anaerobically.

So let's do a quick check.

Which of the following is not a source of energy? Is it A, oxygen, B, glucose, or C, muscles? That's right.

The incorrect answer there was muscles.

So we need oxygen and glucose or glycogen as a source of energy that enables our muscles to contract and therefore us to move.

Okay then, so what exactly is aerobic exercise? Well, it's when we do prolonged physical activity that uses oxygen and glucose to produce that energy.

We can last a really long time when working aerobically, but only if it's a low enough intensity, so low to moderate intensity, to enable that full breakdown of glucose, thanks to the presence of oxygen.

So an example of this might be walking or long distance running.

Alternatively, if we want to create more explosive and really powerful contractions of our muscles, we need to do that anaerobically.

So if we're gonna really accelerate hard, we're gonna be using the anaerobic energy systems. So anaerobic exercise involves those short bursts of really high intensity activity where the body's demand for oxygen exceeds the supply available.

So we can't get enough oxygen into our body fast enough to provide that energy to do things like a 100-meter sprint.

So we find a different way of providing that energy in that fight or flight response, that immediate surge of energy that's required to work at really high intensity.

And that comes from what we call anaerobic respiration.

So anaerobic exercise, in simple terms, is where we're exercising without oxygen.

In actual fact, we are still providing oxygen, but just not enough to be able to provide the main source of fuel for that exercise.

Okay, so if anaerobic exercise means that there's insufficient oxygen being to the muscles because we're working at such a high intensity, it means it can only last for a short period of time.

And the reason that it could only work for a short period of time is because of this byproduct that gets built up.

So an example of this might be sprinting up a hill.

Have you ever tried to sprint up a hill? I hope so.

And you'll probably find you get to a point where you want to keep going but you just can't.

Your muscles are really aching.

So you end up having to slow down or perhaps even stop.

And that's because of this product called lactic acid which builds up in your muscles when you are working at this really high intensity, and it causes muscular fatigue.

Another example, perhaps you did the 400-meter sprint at school.

And when you're just coming around that last bend, you'll have that lactic acid really building up in your muscles, and it might have forced you to massively slow down.

Okay, so this shortfall in oxygen provision that results in lactic acid buildup is also known as oxygen debt.

And we build up this oxygen debt, we've got to repay it during recovery, and we'll look a bit more detail into that in another lesson.

But this is why we're often left outta breath after hard exercise.

So you might have recalled, perhaps you did a 100-meter sprint at school.

And after you cross the finish line, you are out of breath for quite a long period of time, and that's because you're recovering that oxygen debt because you weren't providing your muscles with enough oxygen during the exercise.

So you need to metabolise out that lactic acid.

So during recovery, we send extra oxygen to the muscles, and that extra oxygen breaks that lactic acid back down, and gets rid of it.

So let's do a quick check.

In simple terms, anaerobic means using oxygen.

True or false? That's right.

It's false.

Can you explain why? Okay, so aerobic exercise is in the presence of oxygen, whereas anaerobic exercise is at that higher intensity and hence without sufficient oxygen for that complete breakdown of glucose.

So anaerobic means not enough oxygen or no oxygen sometimes.

So you could actually do some of that anaerobic exercise holding your breath for example.

Okay, so aerobic respiration occurs when glucose and oxygen are combined to provide energy for exercise.

And you might have learned this formula in science.

So we've got glucose plus O2.

what is O2? Of course, O2 is that shorthand for oxygen or chemical formula for oxygen.

So if we combine glucose, which actually has also got a chemical compound name, so C6H12O6 is the chemical compound name for glucose or glycogen, and it's largely, I guess, carbohydrates.

So glucose plus oxygen gets converted into carbon dioxide or CO2 plus H2O or water plus energy.

And it's that energy that enables us to do exercise.

And interestingly, we actually release a lot of energy in heat, which is why, when we exercise, our bodies heat up a lot because of that chemical energy that comes from that.

So if you go for a walk, that's an example of aerobic exercise.

But I'm wondering, can you figure out what happens as that intensity increases? What have we talked about already? That's right.

So during very low intensity exercise, you can burn fats, as well as carbohydrate or glucose.

But as that intensity increases, so as you start to run faster, your body needs more energy, and hence more oxygen is consumed.

So a long distance jog is another example of aerobic exercise and you can, as long as it is at a low enough pace, you can keep jogging.

So once you pace yourself well, you can keep jogging for a really long period of time.

What happens if the intensity increases even further? That's right.

At the other end of the spectrum, we've got anaerobic exercise.

So anaerobic exercise is that very high intensity and short duration exercise.

So like this lady here who's doing some power lifting, she's done a clean and jerk and lifted that heavy weight up over her head, and she'll be definitely working anaerobically while she does that.

And a simple formula for this anaerobic respiration is that glucose on its own, because we haven't got enough oxygen being supplied to the muscles, is converted into energy but with a byproduct of lactic acid produced.

So power lifting or a 100-meter sprint, they're great examples of anaerobic exercise.

Can you think of any other examples? Okay, so that leads us really nicely into our first task for this lesson.

So for task A, I'd like you to do two things.

Firstly, I'd like you to define and explain the difference between aerobic and anaerobic exercise.

And then secondly, I'd like you to provide and explain a simple formula for aerobic and a simple formula for anaerobic respiration.

Pause the video now whilst you do this and come back to me when you're ready.

Okay, let's take a little look at what you came up with.

So this first part of the question asks you to define and explain the difference between aerobic and anaerobic exercise.

So you might have said something along the lines of aerobic exercise is with oxygen.

So with oxygen is the key phrase that you need there, and it provides energy for low to moderate intensity activity like walking and jogging, and can last a really long time or a long duration.

Whereas anaerobic exercise, on the other hand, is a higher intensity and hence provides energy without oxygen.

So no oxygen.

And that's for activities like sprinting where the incomplete breakdown of glucose results in lactic acid buildup and a need to repay that oxygen debt during recovery.

You might not have written quite as much as I've written here, and that's fine, but you can only last a short duration at this high intensity before fatigue happens.

And then onto the second part of this question where I asked you to come up with some simple formulas.

So, for aerobic respiration, hopefully, you wrote that glucose plus oxygen turns into carbon dioxide plus water plus energy.

So here's my quick explanation of those different codes.

And then for anaerobic respiration, we've got glucose being converted into energy plus lactic acid.

And that partial breakdown of glucose occurs if either no or not much oxygen is present.

So we could think of an example of swimming underwater.

Perhaps you're holding your breath whilst you do that.

We have some oxygen already in your body, so you'll use that up and then start to use up energy without any oxygen, so that becomes the anaerobic respiration that creates lactic acid.

But also, if you are sprinting really, really fast, as a consequence of that, you're still breathing and you're still putting oxygen into your body but just not enough to be able to provide as the predominant source of energy for that exercise.

So again, it turns into anaerobic exercise and you can only last so long.

Okay, let's move into the second part of this lesson then where we look at a few more of these examples of aerobic and anaerobic exercise in action.

So for a long time now, it seemed almost impossible to beat that two-hour marathon time, but the same was believed about the four-minute mile until Roger Bannister did it in 1954.

So the Kenyan runner Kipchoge first attempted this in 2017.

He first attempted to beat that two-hour marathon, and he did it at an event organised by Nike, but he fell short by 25 seconds.

How frustrating must that be, running the fastest you can for two hours, the training that went in before that, all of the scheduling and programming, and to miss out by just 25 seconds? He must have been devastated.

So two years later, in 2019, he tried again.

And with the assistance of a British, sorry, a British chemical company called Ineos, 41 pacemakers rotating in teams of seven, and hydration, so he needed to take on fluids, liquids.

So hydration was delivered to him by bike.

He managed to do it in one hour, 59 minutes, and 40 seconds.

Now, unfortunately, it doesn't count as a marathon world record, and that's because it wasn't in an open competition.

But the whole world of distance running has changed since Nike first introduced that Vaporfly trainer, which has now been restricted, but it's thought to improve running performance by 4% in some athletes.

So that trainer really has changed the game of distance running.

And I'm really interested to see, in my lifetime, will it happen that that two-hour marathon time will get beaten in open competition? 'Cause, obviously, the advantage he had when he broke this world record is they picked a very flat course and he had those 41 pacemakers running around him, helping with some of the, I guess, he had the efficiencies of being in behind another runner.

So that was disrupting, so he had less air resistance as he was running, a bit like with sailing, or swimming, or drafting when you're cycling.

It can have quite a big impact if you can tuck in behind somebody and they take some of that headwind.

So it'd be really interesting, won't it, to see if that can now get achieved in a real marathon.

And thanks to those advantages, sorry, advances in sports science, we're seeing some of those world records that have held for a really long time now getting beaten.

So, Andeep's asking, "How is that even possible?" "I'm wondering, well, could you match that pace even for just a hundred metres?" That's what Laura's wondering.

And also, Laura's wondering, "Was he working aerobically or anaerobically?" 'Cause he was doing it for nearly two hours but at a really fast pace.

So, that brings me to another little check before we circle back to look at that Kipchoge in a bit more detail.

So which of the following are examples of anaerobic exercise? Is A, a tackle in rugby.

So that explosive tackle, is that anaerobic exercise? A Tour de France cyclist who's going on for a stage that might last six or nine hours in the saddle.

And what about C, a 100-meter sprinter? Is that aerobic or anaerobic? Well done.

Hopefully you figured out that both the tackle and the a hundred metre sprint are predominantly anaerobic exercise.

So they're really high explosive contractions of the muscles and that lactic acid would be getting built up when they do that.

So anaerobic respiration produces the greatest energy and it produces it really quickly to enable that explosive muscular contraction to happen, but it's got that big downside, doesn't it? Lactic acid is produced.

Can you remember what happens if you produce lots of lactic acid? Think back to that sprinting up a hill example earlier.

And can you think of other activities that result in that lactic acid buildup, other than the sprinting up the hill example that I've just provided? Okay, as promised, circling back then to Kipchoge and that elite endurance racer who trained so hard at that anaerobic threshold.

And the anaerobic threshold is that tipping point where they're producing lactic acid but they're able to get rid of it just fast enough to prevent fatigue.

And maybe you've gone running with some friends or at school and some of them are able to run faster than others and keep going, and that's because they're able to operate at this anaerobic threshold at a slightly higher intensity perhaps than you can.

So they're producing lactic acid as I say, but they're able to metabolise it.

They're able to get rid of it just fast enough for it not to cause that total fatigue of their muscles.

So what do you think would happen if Kipchoge tried to run a little bit faster at the start of his race? So if maybe he didn't have those pacemakers or maybe one of those pacemakers set off a little bit fast for the first marathon, sorry, first mile of that marathon, what do you think would've happened? Well, let's take that into a different example.

So similar to running and to cycling, when rowing, as we can see here in this coxed eight, they're rowing, and if they were to rowing over a long distance, it would be aerobic exercise predominantly.

But if they were doing a sprint race, it would be more anaerobic.

And perhaps during the race, they might sway between one and the other predominant energy system.

So, rule of thumb, if you wanna last more than 60 seconds, then the predominant energy system must be aerobic.

So if they set off too fast in their rowing boat and it went on for more than 60 seconds, that fatigue would happen.

So that's why, quite often, we do what we call a negative split.

So we start off a little bit slower, and then speed up, and hope or at least train hard to the point where we can cope with that slightly higher intensity without crossing that anaerobic threshold.

So then, even in endurance events, we've learned that you're able to put in that sprint finish that might be anaerobic.

And if we go too fast too soon, then we will fatigue and be unable to complete the race or the event.

So let's do another quick check.

Which of the following are examples of aerobic exercise this time? Is it A, thrown a javelin, B, a Tour de France stage, or C, a recreational swim? So just popping out for a few laps? That's right.

The Tour de France stage and the recreational swim will both be predominantly aerobic.

Although, in that Tour de France stage, there might have been a big mountain to climb, and they would've been.

That athlete would've been just crossing over towards that anaerobic threshold as they're going up that really steep hill, but then perhaps they'd recover that lactic acid as they come down the hill the other side.

Let's look specifically at the swimming example though.

So swimming can, as we all know, be performed at a really high intensity.

And in that instance, it would be anaerobic exercise.

But this example of lapse swimming at a more leisurely pace over a longer duration is therefore aerobic exercise.

So you've gotta be really specific in your examples to talk about the intensity and the duration.

So anaerobic is when it's a high intensity, short duration, whereas aerobic is when it's a lower intensity for a longer duration.

And then when we train really hard at something, we find that we can work at a slightly higher intensity and still work aerobically 'cause we've really trained, trained ourselves at that anaerobic threshold.

So that brings us on to most games then.

So here we've got a hockey player, and this hockey player will be using a mix of aerobic and anaerobic respiration during the game.

So when sprinting after a ball, you'll be working anaerobically.

And you can't sprint for that long because of that lactic acid buildup that causes fatigue.

So you'd be able to sprint for an attack, but maybe if you've already sprinted back and then you need to counter attack, that's when you might find you cross that threshold and you can't keep that high intensity up.

But to last the whole match, as we know, these sort of rugby, football, hockey, netball, basketball matches, they last a long time, and therefore you need to have those lower intensity periods during the game where most of the energy will come from aerobic respiration.

Okay, so that brings us on to our second practise task of this lesson.

I'd like you to identify three examples of aerobic activities.

The second part, I'd then like you to identify three examples of anaerobic activities.

And then thirdly, can you identify two examples of activities that utilise both energy systems? So explain when and why they would use aerobic versus anaerobic energy systems during those activities.

Pause the video now whilst you do that and come back to me when you're ready.

Okay, let's have a little look at what you came up with.

So for the examples of aerobic activities, you should have listed things like walking, jogging, long distance running, or long distance cycling, or long distance swimming, or long distance rowing.

They're examples of quite extreme aerobic activities.

Whereas for the second part, some examples of anaerobic activities.

So the key here is they need to be really high intensity for a short duration, so things like the a 100-meter sprint, power lifting, throwing a javelin, serving in tennis, a tackle in rugby, a spike, so that jump and smash down in volleyball, or a slam dunk in basketball.

They're all examples of anaerobic activities because they're really high intensity for a short duration.

So explosive power is involved.

And then the third bit, the slightly harder task was explaining when and why, in two different examples, they use a mixture of energy systems. So you might have talked about a game of rugby, for example.

And in a game of rugby, which lasts for 80 minutes, I'd need to work aerobically during those slow periods of play.

So maybe I'm the fullback, and the play is over at the other side of the pitch, and I'm just hovering around waiting and looking for perhaps a kick to come over towards me.

But then when I want to make a tackle or if I'm involved in a ruck, or a maul, or a scrum, or maybe there's a catcher tackle.

A kick's come over, and I've caught it, and then I'm sprinting for a try.

That's when I would be working anaerobically because it's at a high intensity.

Another example, during a game of tennis.

So we know that a tennis match might last hours in fact for perhaps a three or a five-set match to happen.

So we need to be working aerobically for those long rallies and to last that whole match, but there are explosive muscular contractions like the serve and sprint up to the net for a volley that will be using the anaerobic respiration or providing energy without oxygen, which would result in that lactic acid buildup that we've then got to metabolise out of the body.

Okay, so that wraps us up for today's lesson.

Let's summarise what we've learned about the aerobic and anaerobic energy systems. So aerobic exercise is exercise that uses oxygen for energy production at a low intensity and over an extended period of time, like, for example, long distance running or cycling.

Whereas, at the other end of the continuum, we've got anaerobic exercise.

So that's at a high intensity.

But because it's at that high intensity, we can't get sufficient oxygen into the body to enable us to work aerobically.

And instead we work anaerobically, but we can only last a short duration.

So examples of this are sprinting or weightlifting.

And then we also learned, didn't we, that lactic acid is that product that builds up.

It's a waste byproduct that builds up in your muscles when you work anaerobically, and it's the thing that causes you to fatigue and forces you to either slow down or to stop.

So we really need to.

We can cope with a bit of lactose acid, but we need to be careful not to build up too much.

Thanks for joining me in today's lesson and I really look forward to seeing you again soon.

See you next time.