The Science in Sport

25 July 2013
Presented by Ginny Smith, Kate Lamble.

How has new technology changed the face of sport? This week we delve into the science behind the tennis rackets that professional players use, the diets that top athletes follow, and how systems like Hawkeye are revolutionising the way that rules are enforced. Plus, we hear about new evidence that dolphins refer to each other by name, and sucking or chewing a sweet: which does least damage to teeth?

In this episode

01:00 - "Mark" don't dance

‘Marking’ through a dance can actually be more beneficial than dancing it properly in rehearsal.

"Mark" don't dance

'Marking' through a dance can actually be more beneficial than dancing it properly in rehearsal.

'Marking' is something that most dancers will be familiar with. When you are rehearsing a routine, you don't dance it as you would perform it every time, as it would use a lot of unnecessary energy. Sometimes you just walk through the steps- often not leaving the floor, and sometimes even making hand movements in place of difficult steps like turns.

But a new study Warburton and colleagues at the University of California suggests there may be something more going on than just energy conservation. They asked expert ballet dancers to learn two routines- each dancer practiced one of them entirely full out, and one partly through marking, with the routines counterbalanced.

As well as learning the steps, the dancers had to apply a 'quality' to each movement- such as gliding or floating. They were then assessed for how well they performed the routines. They found that the dancers did better in the routines they had marked than the ones they had rehearsed full out.

This suggests that marking must do something other than conserve energy, and the researchers argue it is due to the dancers' cognitive workload. If you are dancing a routine full out, you have to concentrate on your movement, posture, footwork, balance... the list goes on. They argue that because of this, the dancers' brains are overloaded, and they don't commit the qualities they are trying to learn to memory as effectively.

This has implications for the field of embodied cognition. The idea is that we use evolutionarily older brain systems to help us with complicated cognitive activities- so we make physical movements, like counting on our fingers when adding up, or we talk to ourselves when trying to remember phone numbers. This field believes that externalising cognitive processes helps with memory formation- the opposite of what is seen here.  It may be that when the activity isn't particularly physically demanding, the physical representation helps, but when it is something very difficult, like ballet dancing, it overloads the brain. Marking a dance, rather than dancing it properly, relieves some of this cognitive load, allowing you to commit the steps to memory better.

03:58 - Smarter bed times

Irregular bedtimes in young children may be associated with reduced academic performance, a UK study has shown.

Smarter bed times

Irregular bedtimes in young children may be associated with reduced academic performance, a UK study has shown.A child sleeping

Professor Yvonne Kelly, from University College London, followed the progress of over 11,000 British children born between September 2000 and January 2002. The regularity of each child's bedtime was recorded at ages 3, 5 and 7, with the exact bedtimes logged at ages 5 and 7. At age 7, each child also took reading, maths and spatial-skills tests.

Boys and girls without regular bedtimes, the team found, performed less well in academic tests than individuals who had a more regular schedule. Girls who experienced unusually late or unusually early bedtimes - after 9pm or before 7.30pm - also had reduced academic performance which was on par with children with irregular bedtimes.

The critical age for this effect appears to be three years.

Both girls and boys who lacked a regular bedtime at this age had impaired performance in cognitive tests at age 7, while children who had a regular bedtime at age 3 but an irregular bedtime at a later stage did not show a subsequent dip in academic performance at age 7

The effects of an irregular bedtime also appear to be cumulative, with girls who consistently had an irregular bedtime at ages 3, 5 and 7 performing worse academically than their peers who only experienced irregular bedtimes at two of those ages.

The reason an irregular bedtime at an early age leads to reduced academic performance in young children is not clear. Disrupted sleep may, Kelly and her colleagues speculate, result in less optimal brain development at an early age. They also suggest that children who lack sleep at an early age may have reduced acquisition of academic skills on which they can build in later years, thus leading to impaired performance.

However, there are several other factors which, the group propose, might also have an effect on the quantity and quality a child's sleep, including overcrowding, extracurricular activities or whether they had any siblings. The discipline of a regular bedtime might also reflect on the parental input to a child's upbringing.

Once the group took these factors in to account, they found that the negative impact of an irregular sleep pattern appeared to be greater in girls than in boys.

05:28 - Quick Fire Science - Organ Donation

The World Transplant Games celebrates the sporting achievement of transplant patients. Priya and Claudia give you 11 facts about donation

Quick Fire Science - Organ Donation

This Sunday sees the start of the 19th World Transplant Games in Durban, South Africa.  The games offer the opportunity for people who have undergone a transplant to compete in a variety of competitive sports at the highest level.  Here's this week's Quickfire Science on organ transplantation.

-  1,000 people die in the UK every year waiting for a transplant.

- The first organ transplant was a thyroid transplant, carried out by Theodor Kocher in 1883.

-  Although some organs can be donated by living donors, most organs are only suitable for donation after the death of the donor. The first successful deceased-donor transplant was a kidney transplant between identical twins in 1954

-  A single organ donor can save or improve the lives of up to 50 recipients

- Between April 2011 and March 2012 3,960 transplants were completed in the UK, with organs from 2,143 donors

-   Neither medical condition nor age are necessarily barriers to organ donation; there is no cut-off age for donation and very few medical conditions automatically disqualify you from donating your organs.

-  On average, a patient in the UK will have to wait just over 3 years for a kidney transplant.

-  90% of Brits  say they are in favour of organ transplant, but only around 31% of us are signed up on the Organ Donor Register

-  The World Transplant Games, which start this week, is an international sporting event in which all participants have received an organ transplant. Sports range from swimming and athletics to badminton and lawn bowls.

-  The games first took place in Portsmouth, England, in 1978. It now takes place every two years at locations around the world.

- The current World Transplant games record for the 100m sprint stands at 11.16 seconds - just 1.58 seconds slower than Ussain Bolt's world record time.

07:35 - Chatty Dolphins

Dolphins give each other nicknames and have a complex communication skills.

Chatty Dolphins
with Vincent Janik, University of St. Andrews

DolphinsWe all find ourselves having a chat to our cats and dogs at home sometimes, but they don't normally talk back. This week however, a paper in PNAS looks at communications between dolphins that suggests that they used learned names to address one another. Kate Lamble spoke to Vincent Janik from the University of St. Andrews. 

Kate - So Vincent, what have you discovered?

Vincent - We've studied signature whistles of bottlenose dolphins for a while now and these are very unusual signals, in that every animal develops its own specific sound early in life and then uses that to broadcast where it is and who it is. These sounds also are occasionally copied by other dolphins and when we first found that, we thought that this might be a kind of labelling system or as has been discussed as a kind of naming system perhaps. In subsequent studies, we looked at who copies who and it turned out that it's mainly animals that are very close to each other like mothers and calves or also close associates.

In this a new study now, we've put this to the test by going out into the wild and playing back signature whistles to animal's here off the east coast of Scotland. What we really wanted to do was to find out whether we can address one animal just with a copy of its signature whistle. So, for that to be the case, we had treatment calls which were the signature of animals, but also other whistles from their repertoire and signature whistles from other animals. The result of the study was that the animals really only responded when we copied their own signature whistle, but did not to all the control sounds.

Kate - And you sent us a few of those signature whistles over.  (CLIP) Those two whistles were obviously very different. How do we know that those are signature whistles as opposed to any other sort of random collection of clicks?

Vincent - This is an interesting question because indeed when you have an animal in captivity for example and you can isolate it from the group then the signature whistle is the most common whistle that the animal makes, it is producing it almost constantly. Now in the wild, this is a little trickier. We do know that about half of the whistles they produce are signatures, but the other half, other kinds of whistles, the way we found out what the signatures were in these wild animals here was using a study that we published earlier this year, showing that you can find out what signature whistles are by looking at the specific temporal patterns of whistles. So, if dolphins repeat whistles then the interval between these whistles for signature whistles have very specific values and you can look for those and you can identify then which of the whistles are signature whistles and which ones are not.

Kate - You mentioned that these whistles are learned by the animal when it's quite young. So, does each dolphin create its own nickname in a way?

Vincent - Yes, so one of the big differences we called as names to humans is that the animals develop them themselves, so they're not given to them. The way it happens is it is kind of a creative process in that the animal listens to other whistles in its environment and then maybe chooses one of the model, but then starts to change their whistles efficiently so that it becomes a new signal. So, the animals really do label themselves first in a way and then produce that whistle repeatedly when they are trying to contact the group. And only through this repetition do other members of the group of course learn that this new signal stands for a particular individual.

Kate - How do we know what these whistles are used for? Are they just being used to say hi and let other animals know that they're there or they're used as a warning like we hear other animals sort of scream warnings? Baboons tell other baboons that leopards are near for example.

Vincent - These whistles really just label the identity of the animal, so there isn't any additional information in the shape of the whistle. Now, there is of course additional information always in the voice of an animal, also of a human when we communicate. So, if an animal is afraid for example, then certain parameters change and those can also be extracted from receivera and they can recognise what state the animal is in. And so, through that, the animal can also convey for example whether there is danger eminent.

However, these signature whistles do not function the same way as alarm calls where they label particular predators for example. These whistles really just kind of stand for the individual that's producing them. For other calls that the animals might have, there are food calls that we found as well which kind of seem to be standing for food. But we need further research to see to what extent they really are labels rather than just a kind of excitement call by animals who encounter large schools of fish.

Kate - Is this naming unique to dolphins?

Vincent - The only other animal in which we find something comparable perhaps - apart from humans - are perhaps parrots. There's various studies from parrots that suggests that they may also have a signature call system that works in a similar way. But there's only very few studies so far and this is one of the rare cases where we actually have more information about dolphins than we have about birds even though birds as a group are studied much more extensively than dolphins.

Kate - Why does dolphin communication in particular fascinate us so much?

Vincent - I think there's different reasons for this fascination. On the one hand, people are fascinated with dolphins because they are beautiful animals and you encounter them in the wild.

The other fascination is the scientific one which really comes more from the fact that these animals have these advanced cognitive skills which really rival those of the non human primates. It is a puzzle to find this in an animal that clearly evolved in a completely different environment from ours. So, to have similarities in communication skills between humans and dolphins, like vocal learning for example, or also in other skills like social memory and recognition tasks is kind of a surprise in such a uniform environment.

What it really tells us and one of the interesting aspects about this is probably, a lot of these skills actually evolved primarily in social contexts rather than in perhaps tool manufacturing or tool use context which is one of the other possible origins of advanced cognition that we find in primates.

Kate - So, you're suggesting that us understanding how dolphins communicate can help us understand how our own language evolved?

Vincent - Yes, I think these comparative studies with animals that are quite far away from our own lineage are very useful in highlighting what could perhaps be common reasons for the evolution of complexity. In this case in particular, in communication but I think also beyond this in cognition in general. The fact that dolphins don't have opposable thumbs, don't produce complex tools is something that kind of hints at the more dominant role of social aspects.

Kate - What are the next steps in your work, now that you understand the role of these signature whistles?

Vincent - One of the interesting observations we've made is that if you follow a group of dolphins, every so often, you hear signature whistles of animals that aren't present in the group and one of the next questions really is, whether these are attempts of the animals in the group to find these other individuals or whether they perhaps really use them as referential labels to exchange information about third parties.

We're quite a long way away still to kind of make that discovery I think if it's there, but I think it's a very interesting question to see to what extent perhaps these learned signals could serve as truly referential signals which could only be shown if we show that they are conveying information to a dolphin about another dolphin.

14:40 - Diagnosing the plague

A dipstick test for plague on the way

Diagnosing the plague

A dipstick test for plague on the way

Plague could soon be 
diagnosed faster 
than ever before, thanks to scientists in Germany.

The team, led by Peter Seeberger from the Max Planck Institute of Colloids and Interfaces in Potsdam, isolated an antibody which specifically recognises Yersinia pestis (Y. pestis), the bacterium responsible for plague. This paves the way for a dipstick test which could identify the bacterium in minutes.

The idea of using an antibody to detect bacteria is not new: such devices are available for malaria and HIV, for example. Antibodies recognise bacteria by their antigens, unique markers in their cell wall, to which they bind to destroy the intruder.

The team identified and synthesised a heptose trisaccharide antigen that is specific to Y. pestis, then injected it into mice. The mice made cooresponding antibodies, which the team isolated and purified. Test showed that they bound strongly to Y. pestis, and not to similar Gram-negative bacteria such as Escherichia coli and Neisseria meningitidis.

Y. pestis is considered one of the deadliest bacteria in human history - it is estimated that the Black Death killed between a third and half of the population of Europe. Nowadays the three strains of plague - septicaemic, pneumonic and bubonic - are all treatable with a powerful course of antibiotics, but are usually fatal if left unchecked.

While recent outbreaks have not been on the scale of the pandemics of yesteryear, there are still 1000-2000 cases annually, mostly in sub-Saharan Africa and the developing world. These cases have been difficult to catch as conventional diagnostic methods rely on slow, complex and expensive techniques, meaning blood samples would have to be sent to a laboratory. Not only are such facilities limited in isolated areas, but in many cases the time needed for such tests is all the time the disease needs to kill its victim.  

Now that the team has identified a carbohydrate that is unique to the surface of Y. pestis and expressed the corresponding antibody, it can be incorporated into a diagnositc device like a pregnancy test kit. The team is currently looking for partners to develop the device.

17:18 - Palm oil genes

Close study of the genome of the oil palm tree could result in significantly increased palm oil yield.

Palm oil genes

Close study of the genome of the oil palm tree could result in significantly increased palm oil yield, a paper published in the journal Nature this week has revealed.

Palm oil is one of the most commonly used edible vegetable oils, accounting for 45% of worldwide consumption. There is also a growing market for palm oil as a biofuel.

However, recent years have seen an increasing pressure on oil palm growers to increase their palm oil yield without increasing the land on which the oil palm is grown. This is particularly apparent in countries such as Malaysia - the world's second biggest producer of palm oil - where the area of land available for agriculture has been restricted in order to conserve the country's rainforest.

The answer to this problem might well lie in the DNA of the oil palm itself. Using the recently elucidated full oil palm genome sequence, a multinational group, led by Professor Robert Martienssen and Dr. Ravigadevi Sambanthamurthi, have identified a gene in the plant which is responsible for the thickness of the shell of the oil palm fruit. Plants with two copies of this gene - which has been named SHELL - have a particularly thick outer coating. In contrast, plants which possess no copies of the gene lack any kind of outer layer.

Most importantly, it has been noted that plants that possess only one copy of the SHELL gene have a larger fruit with a thinner shell. These plants produce around 30% more palm oil per metre of farmed land than either their thick-shelled or shell-less siblings.

Previously, identification of these higher yielding plants took 6 years, as farmers had to wait until the plant had grown sufficiently to start producing fruit. This is clearly a slow process, and has resulted in oil palm plantations which contain a mixture of high and lower yielding plants.

The hope is that future growers will be able to genetically screen palm oil plants at an early stage and then select for those plants will have the highest palm oil yield. In this way, farmers would be able to see an up to 30% increase in their palm oil production without increasing the area on which they farm.

19:36 - What causes sudden personality changes?

What causes sudden personality changes?

Hannah Critchlow - Hi, there John. So, scientists think that in a majority of cases of Schizophrenia might be due to problems with how the brain is wired and the bare essentials of the brain's circuits are laid down very early on in development of that person. Then the symptoms of Schizophrenia don't typically show themselves until the early 20s which is what was seen with your sister-in-law. So, why is it that it's in the early 20s that the symptoms manifest? Scientists think it's because at about 15 years, all the way up to the mid-20s, at this stage, there's something else happening in the brain and that's something called synaptic pruning. So, if you imagine that your brain is full of leaves and twigs, and branches and trees, these are the nerve cells connecting with each other using these twigs and these branches, and these leaves. Well, they're pruned away, probably under hormonal direction. So, as soon as you hit puberty, this pruning process takes place which removes any surplus connections in the brain. By removing any of these surplus connections in the brain, you're unmasking any underlying circuitry problems which may be why your sister-in-law developed the symptoms of Schizophrenia in her early 20's which is what most people see. Another observation that we see for women that have Schizophrenia is that you get a peek of incidence of people that come and visit a psychiatrist with first episodes, the first symptoms of psychosis, about the time of the menopause. We think this might be because of their hormones, the dip in oestrogen during their menopause is actually again affecting this synaptic pruning and these connections between brain cells and so therefore, unmasking again these underlying neural circuit problems that were laid down in very early life for someone that has Schizophrenia. I hope that answered your question.

22:03 - What makes things sticky?

What makes things sticky?

Philip Broadwidth - Well David, that's a very good question. Basically, there are two kinds of things that you could think of when you're talking about stickiness. When you're talking about things like glue, sort of a super glue, there's often a chemical reaction going on and when you're talking about things like honey, it's not an actual chemical reaction but just interactions between the molecules. So, for example, super glue is made from something called methacrylate and in the bottle, that's fine, but when it comes into contact with water either in the air or on your fingers, then it starts a chemical reaction which bonds all of the molecules together into big long chains which is what sticks everything together, then the chemical bonds hold everything together. Same for lots of other kinds of glue, but things like sugar or honey which just feel kind of sticky, that's generally down to forces that are not actually chemical bonds, but interactions between molecules. So, some of those would be hydrogen bonds which are the same interactions as between water molecules, but a sugar has lots of sites that can hydrogen bond which means that there's a more cooperative effect. It's like putting lots of hooks into a surface and then trying to pull on it. If you've only got one, it's relatively easy to pull away, but the more hooks you have all acting together, the more sticky something is.

The other alternative to that is something called Van Der Waals forces which are generally to do with the surface area, it's a charge interaction. Things like gecko's feet have exceptionally high surface area which is what allows them to stick to glass for example. But that's also the same forces that are in play when you look at things like post-it notes. They have a material on the back which is in very small spheres. When you press it down, that increases the surface area and allows it to stick to the paper, but it's not such a strong interaction that when you peel away the post-it note, it leaves the paper that you'd stuck it to intact.

24:27 - Technology in Tennis

Technological advances have revolutionised tennis since the last british winner of the men's Wimbledon singles title.

Technology in Tennis
with Alison Cook, Cook Associates

Britain has recently been celebrating its first Wimbledon Men's Single ChampionJustine Henin at the 2006 Medibank Tennis International in 77 years, but between those two victories, the game of tennis has been completely revolutionised. Not just due to the introduction of professional contracts and sponsorship, but also because of technological advances in rackets and balls which allow players to hit record-breaking serves of up to 163 miles an hour. Ginny Smith caught up with Alison Cook from the Sports Engineering Consultants, Cook Associates on a local tennis court to find out about the technology that's changed the game.

Alison - So, the first development you saw from the Dunlop wooden rackets was aluminium rackets which, aluminium is a much lighter material which maintains a similar strength. And so therefore, the players found it lighter to play with and then easier to swing. But then what we then advanced through was composite materials where you have carbon fibre composites. The essential property that those materials allowed you to have was what we call the swing weight.

Ginny - So, what exactly is the swing weight? I guess, if you're trying to swing a very heavy racket, you have to put a lot more energy into just doing the swing and you don't get as much energy to the ball. Is that the idea?

Alison - Perfect! You've got it in one shot. The best way to think of it is it's the way the weight or the mass is distributed along the length of the racket. Just like if you were carrying a frying pan full of lots of bacon and eggs or something which there's too much in there, you would feel that it was heavier, similar with the tennis racket. If you put more weight into the head of the tennis racket, it will feel heavier to the tennis player and so, the way the weight is distributed along the racket makes a big difference to how they play the shot.

Ginny - So, other than weight, what kind of things have changed in tennis rackets, in the materials they're made of to help people get these really powerful fast serves that we're seeing nowadays?

Alison - The other thing that's changed which is important is the head size. Of course, if you have a bigger head size then you actually have got more strings in there. You've got more ability to store the energy and to then return the energy into the ball. Just to give you the numbers, in 1970, the racket head size was about 70 inches squared and now, they're more like 105 inches squared. The Williams sisters are usually known for playing with one of the largest sizes of racket head, 110 inches which is what the men play with often - the biggest rackets. Even if you don't play tennis, you might have heard of the term 'sweet spot'.

Ginny - Is that the area of the racket that you're aiming to hit the ball with?

Alison - That's right. The place on the strings where the ball receives maximum energy transfer, the maximum power to the ball, it's all about energy transfer. So, the ball is coming with a certain amount of energy towards the tennis player, it hits the strings, the energy is stored into the strings and into the ball, and then the strings return the energy into the ball, and then the ball flies off.

Ginny - So, we've got a pair of rackets here that you brought with you and they look pretty much the same, but there's something different about them. What's that?

Alison -  Well, one of the things that affects the player's shots and the power of the player's shots is not only the racket material that it's made of, but also the type of string that's used. All sorts of things will affect that - the length of the string that's used, the type of the string, the cross section of the string, and the tension at which the racket is strung. So, we've got these two rackets here and they're the same racket design. They're the same head size, but they have different strings in them and if you listen to them, you will hear a different noise.

(Low pitch string sound)

(High pitch string sound)

Ginny - So, it sounds quite nice. It sounds a bit like a guitar, but the second one sounded a bit higher pitched to me. Why is that?

Alison -  The higher the note, the more tightly strung the racket is. Now, if it's strung more tightly then you lose some power but you gain control. The reason you lose power is because the strings are all about absorbing the energy, elastic potential energy it's called. Just like a rubber band, you store energy into the rubber and then it pings back. That's what the strings are doing. They're storing the energy of the ball into the racket and then they're returning it to the ball. So, if you have a tightly strung racket, you get less power into the strings and then less power back into the ball, but you do gain control. So, that first racket was strung with lower tension and so, there will be more power.

Ginny - So, we've talked a bit about the rackets, but what about balls? How have they changed and how does that affect the game?

Alison - One of the things people will automatically notice when they open a new can of tennis balls is that it makes a really lovely hissing noise. That's because the balls are kept at pressure so that the behaviour of the ball is repeatable. When the balls are manufactured as well, they are pressurised and so, that's why you will notice that when you take a new ball out of a can, most of us will not be able to squash the ball.

Ginny - Okay and you've got a tube of new balls here that we can have a look at.

Alison - Yes, I do. (opens the can)

Ginny - So, what's the difference between these and some balls that have been used for a while?

Alison - Well, we were watching my kids playing earlier and they were playing with some training balls which we've been using for quite a while and they've become very soft with time. That's why when you're watching any Wimbledon match, you'll see that they have new balls every so often. So, they change the balls every 9 games and that's because those players are hitting the balls so hard all the time, they knock the stuffing out of the ball literally and the pressure within the ball deteriorates, and it becomes much softer. So, when you first open a tube of balls like we've just done, it's very hard. It's pressurised inside.

Ginny - I'm trying to squash that in my hand and it's squashing very slightly, but I'm having to put quite a lot of effort in to get any sort of give at all. So, we've got a training ball here which has been used for a while and yeah, I can get quite a good dent in that really quite easily, just by squishing it. So, you can definitely feel the difference there. What kind of difference does that actually make to playing with them?

Alison - So, it's all about the energy transfer. With the new balls, you'll get far more energy transferred into the ball from the racket and the player than when they're soggy. Energy is always conserved. So, when you deform the ball like that, you're actually absorbing energy into the ball. So, some of the energy that should go into creating the speed of the ball actually goes into deforming the ball.

Ginny - At Wimbledon, they keep them at certain temperatures as well. Is that because of the same idea?

Alison - Temperature will affect the pressure of the air inside the ball and so therefore, if you have a different ambient temperature or different outside temperature, you'll have a different pressure of the ball. And so, the same parameters and design parameters, the same effects that we talked about in terms of the softness of the ball will be affected by the temperature of the air inside and the pressure of the air inside.

31:35 - Nutrition in Sport

Nutrition plays a key role in physical fitness. But can it really help us run faster or jump higher?

Nutrition in Sport
with Phil Watson, University of Loughborough

It's not just technology on the pitch that's helping athletes change their game. A fridgeAfter a fantastic couple of years for sport in Britain, we've heard a lot about the nutritional requirements of high performance athletes. From Michael Phelps' 10,000 calories a day diet to criticisms that Chris Froome might not have been eating enough in the year preceding his Tour de France victory.

But what effect does what we eat have on our physical performance? Could changing our diet really make us run faster or jump higher? Kate Lamble spoke to Dr. Phil Watson from the University of Loughborough. 

Kate - So Phil, what do athletes need to watch in their diet?

Phil W. - It's a difficult question to answer because athletes are so diverse. The nutritional requirements of a 50-kilo gymnast for instance would be considerably different to the nutritional requirements of a 100-kilo heavyweight rower or Mo Farah running the 10,000 meters. So, there's certainly no one-size fits all. There's certainly evidence that high level athlete's performance will be impacted by what they eat. But you're not going to make a mediocre athlete an Olympic champion by eating correctly, but certainly, you could lose that Olympic gold medal by eating poorly.

Kate - Is there anything in particular that will help most athletes perform on the day? What should you be eating just before your race?

Phil W. - Well, researchers over the past 100 years has supported the idea that carbohydrate is important to performance certainly in a more prolonged event. So, something like the Tour de France or a marathon or the 10,000 meters that I mentioned previously. Carbohydrate, we obtain that from a variety of foods, things like pasta or rice, potato and sugary type foods. Carbohydrate is important because it's the primary fuel for exercise. So certainly, the evidence suggests that carbohydrate is important.

The other dietary component that's kind of persisted over the years obviously, dietry fads come and go, and you see these fad diets, but the other staple of sports nutrition is fluid. We lose fluid as we exercise particularly when we exercise in the heat. We sweat, we perspire, we lose fluid from our body and it's important that we replace that.

Kate - As well as a dietary plan, professional athletes also often take supplements. Why do they do that?

Phil W. - Well, there's a number of reasons for that. The most apparent reason is to improve their performance. There's a little bit of evidence that some supplements do that. A substance called creatine for instance has consistently shown to improve strength and power in those sorts of athletes. Caffeine is another supplement that has consistently been shown to improve performance. There are a few 'new kids on the block' substances like beta alanine, beetroot juice which there's a bit of growing evidence now to support their use.

Kate - Talking about beetroot juice, one of our team members is a very keen rower and she's been bringing in these beetroot juice supplement drinks that they've been giving out. Why particularly do we think that that might be helpful to athletes?

Phil W. - Beetroot is rich in dietary nitrate. Nitric oxide is very important for the body for a number of reasons. It regulates blood flow and it's important in muscle metabolism as well. Research over the past 4 or 5 years coming out of the University of Exeter has really shown that by ingesting beetroot in these beetroot juice shots that have become popular, you increase dietary nitrites which is a product used to generate nitric oxide within the body and it does certainly seem to improve performance.

Kate - Some of these supplements you mentioned earlier as well like caffeine are obviously also drugs. Where is the difference between the supplements that we take to help our performance and the supplements which we now consider in certain sports to be prohibited aids that go beyond what we normally eat?

Phil W. - There actually a very fine line. Caffeine for instance was on the World Anti-doping Agency prohibited list up until 2004 and you were allowed a certain urinary level of caffeine. Above that, you would be banned for using too much. My PhD supervisor, Professor Ron Maughan used the adage that, if it works, it's probably banned and obviously, there are some exceptions. So, caffeine and creatine are two that have hung around and have persisted in terms of nutrition.

Kate - We hear a lot about athletes who were banned for doing illegal substances or substances that are prohibited in their sport and some of them say, "I didn't know it was in the supplement that I was taking. I didn't know it was within my diet." Why is that the case? Why are they so confused about what they're consuming?

Phil W. - It's an interesting one. So, the World Anti-doping Agency rules are very explicit and strict liability applies. So, if you test positive, you can't point a finger and say I don't know. That doesn't stand up in court. But there has been a number of cases over the last I'd say, 10 to 15 years of athletes testing positive and going through that exact same scenario. They say, "I didn't take anything. I'm innocent." And then a study conducted in Germany a few years ago now, almost 10 years ago analysed dietary supplements brought from all over the world and found that some of those supplements were actually contaminated with steroid prohormones - precursors of anabolic steroids. And these substances weren't included on the label.

So, the authors of that particular study concluded that there's cross contamination occurring and this contamination could lead to positive doping tests in athletes. Certainly, some of our research has demonstrate that very trace amounts of these pro-hormones substances added to a dietary supplement can cause an athlete to test positive. So perhaps there is some link there.

Kate - When you talk about precursors to steroids, is that something that is actually a steroid or is that something that later gets turned into it somehow?

Phil W. - Yeah, it's a substance that later gets metabolised into a steroid. So, some of the substances are made available as dietary supplements, particularly to the body building industry, to the guys who are trying to get massive and look good on the beach. There's actually very little evidence that they do enhance muscle growth, but the body builders like the idea that, "I'm going to take a steroid precursor and that will make me grow muscle faster." So, these supplements are on the market and yeah, there's some evidence that the company that are making these types of supplements, there's some degree of cross contamination occurring and that's probably what's led to some of these positive doping cases.

Kate - By this point, sports nutrition has become a very exact science and we all hear about how a sports nutritionist is embedded into almost every professional sports team. Where can we go next? What's the next stage in us, helping develop nutrition that can help our athletes?

Phil W. - I don't know if sports nutrition and sport science has been slightly slow to adopt other areas of science, but in the last 10 years, molecular biology has become a big explosion area within exercise, physiology and sports nutrition.

So, we're really starting to understand some of the molecular processes going on within the muscle. The signalling that tells the muscle to grow in a certain way and that's being used by sports nutritionists now to look at the interaction between diet and training to try and maximise the training games from the given bout of training.

So, something that has become popular in the last couple of years and some of your listeners may have heard of it is the idea of train low, compete high and that means you train with low carbohydrate availability and then you compete with high carbohydrate availability. That seems to be beneficial because training with low carbohydrate stimulates a greater adaptive process. So, your body is under more stress during the training session. Your body responds to that stress and you seem to get greater training gains. Now, you can't undertake all your training sessions in this low carbohydrate situation because eventually, you'll breakdown and it's difficult to maintain the intensity. So they'll perhaps do two sessions in one day, one session with high carbohydrate availability which allows them to really push hard and then one session with low carbohydrate availability which puts this additional stress in the body and seems to enhance the adaptive process to trainings.

40:04 - Hawkeye in sport

We have recently seen the emergence of technologies to help enforce the rules of various sports. We ask how Hawkeye works.

Hawkeye in sport
with Luke Aggas, Hawkeye Innovations Ltd

Advances in sport technology aren't just aiming to improve athlete's Cricket Ballperformance. Recently, we've seen the emergence of technologies designed to help officials enforce the rules of their particular sport. Probably, the best known of these is Hawkeye. Ginny Smith spoke to Luke Aggas, Director of Tennis at Hawkeye Innovations Ltd to find out how the system works.

Luke - It's a camera based system with the cameras located at the back of the arena. So, it's a totally non-invasive system. There's nothing put inside the lines of the courts or the tennis ball itself. It utilises some bespoke and advanced vision processing techniques to detect movement within the field of view of each of those cameras and then combines what it believes to be a tennis ball from each of those field of views to give you a 3D position relative to the court lines.

Ginny - So, Hawkeye is not just being used for tennis. It's used for cricket and it might be being brought in for football, but these sports have quite different balls. They're different colours and in the case of football, it's quite a lot bigger. How does that affect the technology?

Luke - We're very fortunate in terms of the general colour and the size of a tennis ball, so it's very consistent from event to event. In the cricket, where the system was first used, depending on the match or the test or the tour a different ball can be used in terms of the colour. A ball can discolour especially they start using the white ball and although people at home believe that the Hawkeye is automated, no-human intervention sort of system, in order to make sure that the system is tracking optimally under all conditions - be that the ball has changed colour, a shadow has come across the tennis court, or with all electrical equipment they'll be some moment where, something will need powering down and powering back up again. So, that's the reason why we stick up more cameras and there's some human intervention to make sure the system is working optimally throughout.

In the football, the ball will change between your optimal conditions through to, obviously, we know the use of the orange ball in snowy conditions. Equally, we're very, very used to the pattern as well as the colour changing on the ball between competitions and that's something that we're given clear direction on well in advance of those competitions, what ball they're going to use and we actually are given samples of that ball in order to fully test the system for robustness and a reliability point of view to make sure the system is working optimally under all conditions.

Ginny - So, with cricket, obviously, Hawkeye is used in leg before wicket calls where you're having to predict something that didn't actually happen because you're looking at whether if the leg hadn't been there, the ball would have hit the wicket. So, how do you go about predicting something like that that has so many variables?

Luke - The cameras that we use in cricket frame rates of those cameras are a lot greater than the tennis primarily because of that reason. So, we're trying to achieve as many frames as possible, using ultra-motion cameras running at 350 frames per second. Obviously, it's not easy to validate and test the system as something that effectively didn't happen. But obviously, in a similar way, to a predict development within the tennis from a frame by frame point of view, the system will then forward predict the fly path of the ball.

Ginny - You must have to take into account things like the texture of the surface and the direction of the wind. Is that all part of the software?

Luke - It is. We calculate the court pace in a tennis sense, the coefficient of restitution, coefficient of friction on the playing surfaces that we track upon. In the tennis, a lot of people say, "What about the wind?" We're not effectively predicting the ball flight within tennis. We're joining the dots together. We're capturing the flight of the ball and therefore, if there is a given lob or shot under windy conditions, it does do a sort of boomerang then we're just joining those dots together. So, that is all taken into account. We are capturing the actual video footage rather than what the system believes. In a predictive development within the cricket that is an unknown obviously in that short space of time between the ball bouncing and the ball contacting the player's pad and then passing the wicket. So, in that space of time, for wind to have a significant influence on the ball, it's extremely, extremely unlikely and obviously, the relative weight of the cricket ball is influenced by the wind that much less than a tennis ball.

Ginny - So, with football, you're using it as a line technology, so just to see whether a ball has passed the line and is a goal. Is there any way you could use it for other things perhaps to see if a foul was really a foul or if it was just a tackle, whether they actually touched the ball, that sort of thing?

Luke - As with all sports, we kind of create the technology for our customers and at the moment, goal-line technology is being the only specification in terms of any form of video replay and we've created that technology and hopefully fix that age-old problem. Saying that, we are very, very open to other suggestions if this has opened the door on using video to best officiate football, offsides being a clear one. Also there are technologies that we have provided in other sports, as well as the Olympic games, where we've taken in numerous video feeds from standard broadcast cameras, synchronised those cameras so that you can see what is happening in each of those field of views or in each of those cameras at that exact moment in time. So, to give rugby as an example, they obviously go to the officials to see whether the try scorer or supposed try scorer's foot had touched the line prior to the ball contacting in the floor. At the moment, they look at that on a camera by camera basis and the technology, the way we're currently various sports is to be able to synchronise that footage and to be able to see the output of that, all at the same time.

45:55 - The problem with Hawkeye

As accurate as Haweye can be, will it ever replace officials?

The problem with Hawkeye
with Nic Fleming, Science Journalist

Hawkeye claim that their system is accurate and reliable, but science journalistAmerican Football Referee Nic Fleming warns that definitive calls will always be an impossible goal. Ginny Smith asked him about his point of view.

Ginny - So Nic, Hawkeye seems like quite a good way of preventing arguments in sport. What is it that you think the problem is with the technology?

Nic - It can be used obviously to replace a human referee. However, all I'm really saying is that if we do that, when you screen recreations using Hawkeye, I think there should be something on the screen to acknowledge that it's not a 100% representation of reality that there is a level of uncertainty and there's always going to be some inaccuracy because it is just a re-creation, a measurement. I think it would be very useful for that to be an acknowledgement of that on screen.

Ginny - So, at the moment, we use human referees and that sort of thing and of course, they're not going to be accurate. So, Hawkeye is going to be an improvement on that, so why do we need to point out to people that it's not accurate?

Nic - Well, because as things stand, technology of these kinds are obviously playing a larger and larger role in our lives. I think it's important that we have a mature relationship with some of these technologies. There is a danger that if you watch a Hawkeye replay from tennis for example, when I saw that a couple of years ago, when I was watching those, I would assume that that was an accurate representation of reality and I believe that that's what most people think when in fact, that's not the case. There's always going to be inaccuracy there. I just think that it's important that we use technological tools in an adult way and we understand their limitations and we don't just bow down to them and assume that they are always going to be correct and accurate, that we just acknowledge that there is an uncertainty there.

Ginny - So, how accurate would something have to be for you to accept that it was accurate? So, Hawkeye claim that their tennis system can predict up to 3.6mm which is tiny compared to a tennis ball. Is there really any difference there?

Nic - That's right. Well obviously, I mean, in terms of football, the big controversy was in 2010 and the Frank Lampard goal that must've been close to a meter over the line, looking at the video footage and obviously Hawkeye would've done better than the referee there and would presumably in 19 out of 20 other cases.

But there's a danger as we go forward when we're going to be able to produce footage that looks like real video footage with computers. And for political economic usages, there's a danger that people are going to end up being fooled by some of that footage. So, when we have these representations, I think it's important that we know what is real footage and what isn't. Things are going to become more and more realistic. So, we can all agree that we're going to use the technology and that that could be more accurate than the referee, but let's not pretend that it's 100% accurate.

Ginny - I think the only problem with that is that as humans, we find it quite difficult to understand uncertainty. So, if someone tells you that this is the answer but we're not certain that it's the answer, people will tend to assume that that means that it's wrong. Could that not lead to meaning more arguments?

Nic - Well, I mean, this really leads on to my other point really which is that, in a lot of scientific debates, that are in the public eye, be that sort of nuclear power or genetic modification or climate change, the media is constantly trying to fit science into a yes/no equation. Science isn't about yes/no's it's generally about probabilities. It's scientists saying, "We've got a model and we're 98% sure that this is going to happen." But this is constantly simplified. So, I suppose the other argument is that, if we can be a bit more open and mature in the use of tools like Hawkeye, if we can say, "Look, this is going to be much better than a human referee. However, there is an uncertainty."  Perhaps that would help to spread the message amongst lots more people that in science, there is uncertainty and we have to be able to cope with uncertainty. We shouldn't pretend it's not there. That's my concern. We're pretending that uncertainty isn't there. Let's not patronise people in that way. Let's be upfront with people.

Ginny - So, we can kind of use these sports as almost a training ground to help people understand uncertainty in bigger questions as well.

Nic - Absolutely, yeah.

Ginny - And the most important thing when it comes down to it in sport is not actually that the call is correct 100% of the time, but that it's unbiased. So, at least with these electronic judges, they're unlikely to have a leaning one way or another.

Nic - I guess that's the case, yes. But then I mean, there are other people who will oppose these technologies for other reasons. I mean, a lot of the interest in sport is the drama, the controversy, the argument, the discussion, maybe in the pub afterwards. That's another argument that some people make against the use of these sort of technologies.

50:53 - Is it more tooth-friendly to suck, or crunch a sweet?

Is it more tooth-friendly to suck, or crunch a sweet?

Hannah - So, suck or chew? Which one is best for your teeth? Cambridge University dentist Mike Williams who's also a Senior Clinical teacher at Guys Hospital London wrote in with this.

Mike - Okay, so when you eat foods that contain sugar, the bacteria in your mouth utilise this sugary substrate as their food and as a by-product, they produce acid. It's this acid which causes your teeth to decay. The bacteria will go on producing acid for about 20 to 30 minutes after the sweet thing has gone. This is referred to as an acid attack and during this period, the teeth are in an environment where they might decay. They might not decay, but everything is in place that would allow that to happen. Thus, the frequency with which sweet things are eaten is important. If another sweet thing is eaten say, 10 or 15 minutes later, there'll be another acid attack and another, and another, and so on. Here, the acid attacks will merge into one big acid attack and the teeth will certainly decay. So, when sucking the sweets slowly, it means that sugar is available for a longer period of time. The acid attack would be as long as the sweet was in your mouth plus 20 to 30 minutes.

Hannah - Thanks, Mike and Richard Crosby, a Dentist in Norwich agrees, adding this caveat.

Richard - The person who ekes their sweets out and sucks them for a long length of time is likely to be doing more damage than the person who crunches them up and gets rid of them in a short space of time. I think the only other thing to bear in mind is that crunching sweets could cause some physical damage rather than the bacterial damage from decay. So, you might find that if you are crunching hard sweets and you've got compromised teeth, you might actually be chipping bits off your teeth as well.

Hannah - So, if you're eating sweet sugary things, try to guzzle on them as quickly as possible, but be careful not to crack your teeth, and try to clean your teeth directly after eating.

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