As promised, a bit lighter fare this week.
- Hard to believe we are already two weeks into August. One positive take away from the end of summer: The greatest league in the world is about to start back up this Friday. If you are a fan, let us know your team. (Here's a hint for Dr. H's team: North London)
- There is an amazing amount of physics that goes into curving a soccer ball. Hopefully this doesn't cause any of you to scramble for a calculator in the middle of a game. (Here is a great video showing the magnus effect)
- Head injuries continue to be a problem in soccer at all levels, including professional. The addition of the "concussion substitute" last season was a great move, but there are probably many more steps that can be taken to protect players.
- For those of you who for some reason don't follow soccer, here is an article about some of the physical and physiological differences between sprinters and other athletes.
47 comments:
The article, "Soccer players' head injury risk could be reduced with simple adjustments to the ball" talks about an undervalued problem that has become more and more of a serious issue over time. The amount of times a player heads the ball, especially even in one game, is a lot and could result in damage of neurological structure leading to concussions. Even if it is a simple experiment of testing the pressure or wetness of the provided soccer balls throughout the game, it can make a big difference in the player's health. I'm surprised though that this issue was not brought up or looked at earlier since the lasting effects of heading the ball can be detrimental. The experiment concluded that using a size 4.5 ball was safer than using the size 5 ball that professional players usually use yet this action has not been officially implemented. Though this conclusion still needs to be tested more in college or professional games, I agree that other factors may take place, affecting the ball, so trial is still in session. Hopefully in the future, the type of ball and other regulations will take place to ensure a safer game of soccer.
The second article I read, "Physical Characteristics of Sprinters and Runners" surprised me with the different characteristics between sprinters and endurance players. Some of the attributes seemed accurate depending on the skill but the main element I'll be focusing on in my analysis is height. Sprinting is often said to be suited better with taller runners since their tall legs can kick up momentum. This can be somewhat true but as the article stated, "So when it comes to looking at the stature of sprint athletes ... the athletes lining up at the start might very well be tall, medium and short in stature". Sha'Carri Richardson is officially America's fastest runner in America with only being 5'1" while Florence Griffith Joyner, the fastest woman in the world, is 5'7". There is a big difference in the height, 6 inches, yet both women are incredibly fast and talented depending on the style of their running. However in some cases, height can play an important factor like in tennis. Taller players are said to have an advantage since they can reach higher balls at net, hence good volleyers, and can cover more court faster. Along with this, basketball players are usually very tall so they can reach the ball and shoot hoops easier. Disregarding height, other sports may favor buffer or stronger candidates, like mentioned in the article, but it all depends on what the sport is focusing on and the skill required. Overall, height can be a tipping point or can be completely irrelevant in the case of the sport being played.
The article “Soccer players' head injury risk could be reduced with simple adjustments to the ball” was an interesting read for me, as I did not know how much research was done on soccer balls. This article made me realize that not only are there several different types of soccer balls, but there is also loads of testing and research done to ensure that they are safe to use. I also assumed that soccer balls were waterproof, so finding out that soccer balls could absorb water and become even more dangerous was shocking to me. After reading this article, I now realize that soccer can be extremely dangerous if these studies were not done. Even small changes like using a dry ball, closing your mouth while hitting the ball with your head, and using the right size ball can decrease the risk of head injury. The fact that soccer was created in the 1860s and there are not very many studies about ball pressure is eye-opening, as millions of people play soccer daily and can potentially injure themselves. The article mentions how the velocity of the ball can determine how hard the ball hits and how it is difficult to control the velocity, so hopefully more studies are done in the future that research how players can maintain a safe ball velocity to ensure that everyone playing is safe. Overall, I’m glad that new studies are being done to make sure that all athletes remain safe during games, as sports will always be a big part of many people’s lives.
The first article I read was “Soccer players' head injury risk could be reduced with simple adjustments to the ball”. It was interesting to learn the many ways that soccer players could risk concussions. Concussions are also a problem that does not get as much attention as other injuries, but can have the biggest impact long term as it is a detrimental factor for the neurological structure. Knowing that if a ball gets waterlogged it can be hazardous is important to know for many soccer players, as we often will play soccer in the rain without any concern. Learning the science behind how to decrease risk of concussion is important in all sports, as it can protect the athletes through protective measures and policies. It can also help to develop new sports gear to give more protection to athletes.
The second article I read was “Physical Characteristics of Sprinters and Runners”. I found it interesting to know that there are different features that allow someone to be a better sprinter and better at endurance. It is obvious that tall people would be better at sports such as basketball and volleyball, but I did not know that height affected your overall speed. It can help you reach top speeds, but being tall also delays your acceleration, which makes it harder in the first few seconds of a sprint. Short people having more endurance also makes sense. In my soccer team, the shorter people tend to last farther distances than the rest of the team, and are also the most shifty soccer players. It is important to do research into the biological features of athletes so that we can choose our top contenders for competitions, and also get a competitive edge. This is best seen in pole vaulting, where tall people get a theoretical advantage, so it would be better to choose taller athletes to train at events such as the Olympics. It can also help in creating a proper diet for specific athletes in specific events. Also, my favorite soccer team is Chelsea.
In the article, “Concussion substitute trials get go-ahead and FA ready to act in Cup”, it’s interesting to see how neurology comes into the play of athletics. A sport which a myriad of people are familiar with relates to the brain in many ways unimaginable. In terms of concussion protocols and injuries, American football is where my mind goes. I have always been taught that football is mainly associated with concussions injuries, especially in professionals due to the aggressive patterns with tackling and butting heads with helmets. However, it had not occurred to me that soccer players have the risk of concussions as well. Hitting the ball with your head during games and practices everyday could definitely lead to secondary impact to the brain. I am in agreement with the trials taking place, since the size 5 soccer ball can produce plenty of damage to the structure of the brain. What sports can do to one’s body is beneficial, yet risky at times. Some may not even know that their brain is injured during the short-term. Conversely, in the long-run, injuries to the brain could lead to other illnesses, alongside concussions.
In the article, “Physical characteristics of sprinter and runners”, I was surprised to find out that there was quite a bit of a difference between sprinters and endurance athletes. I would expect that they would fall in the same category regarding skill sets. However, the article says something different. In fact, it even mentions how height and body mass implements a role in speed uphill. Highlighted in the article, “the shorter athlete or player will be better able to accelerate and control their own body weight compared to a taller individual”. Due to the body weight, the shorter individual will be able to accelerate faster than the taller individual. Not only do I find this fact intriguing, but also the fact that size plays a huge role in the skill set of throwing. The more body mass one has, the farther and faster it may be to throw. It simply depends on the strength, size, and height of the individual. It truly is fascinating to see which person acquires a certain skill set due to their physical characteristics.
Before reading the article "Physical Characteristics of Sprinters and Runners," I never knew that there were any differences between sprinters and endurance athletes. While watching the runners in the olympics, I did notice that sprinters had much different forms than the endurance runners. They also did have more visable muscles than the endurance runners did.The fact that so many factors go into what type of person may be best suited for sprinting and endurance is very intersting as well as surprising. As a basketball player, I know that height in the sport is important, but I did not know that it played a part in running and gymnastics. I have seen taller runners with longer strides win in a lot cases, but I have also saw shorter ones win as well, so I never thought about it in that way. So by knowing how all of these factors go into running, coaches are able to choose the best contenders for athletic competitions.
Head Injury Risk for Soccer Players: This article completely sparked an interest in me as someone who used to play soccer and fulfilled so many questions I had during my season. As the article started to talk about the causes of injury and how to reduce the risk, I learned the soccer balls are actually not waterproof. Rather, I found out the main reason that coaches have to switch out the soccer balls if we are playing in the rain is due to the fact that the soccer balls actually can surpass the ball weight limit as they can absorb the water and cause an injury. Many of the risks they researched seemed very minor to me at first, however, as I read further through them, I realized the extensive research was actually very important to the future players. Things like the studies for different pressures done, the ball size, and weight all proved to me that soccer is a lot riskier to play than before. With all of this being said, these studies being done may seem minor to people at first however the entire purpose behind it is extremely vital for the safety of many soccer players in the future.
When I think of concussions in sports, I usually think of football because the players are constantly experiencing strong impact forces with either other players or the ground. Since concussions are so often linked to football over any other sport, maybe that is part of the reason why there is not much data on the effects soccer balls have on causing concussions in soccer. As the article “Soccer Players' Head Injury Risk Could be Reduced with Simple Adjustments to the Ball” mentioned, a professional soccer player may head the ball 800 times over the course of one season. For that amount of impact, there should definitely be a larger emphasis placed on finding new solutions to lower the risk of concussions. Based on this study, it seems like a new solution might not be too complicated, but there needs to be more data collected for any real change to be made. Regulating ball pressure and water absorption to maintain conditions that are safer for players is a great idea to reduce brain injuries because players would have safer playing conditions without having to change the way they play the game. Even if the soccer ball needed to be subbed out several times during a single game to make sure it wasn’t too wet, that slight inconvenience would be worth the benefits players could see by having significantly less brain injuries.
The Physics of Soccer:
I always thought that physics was incredibly challenging or a subject that I wouldn't understand. However, as I was reading this article, I found that I surprisingly understood a lot of it. This really introduced me to the topic of physics. I really enjoyed the video the website had at the end because it helped me to connect math and science with something that I see everyday. Many of my family enjoy the thrill of watching soccer matches. I found the Magnus effect interesting because it incorporates Newton's 3rd Law of Motion, which is a topic that I am familiar with. I also now, hopefully, will be able to do a curve ball.
"Physical Characteristics of Sprinters and Runners": I read about the different characteristics between sprinters and endurance players, which led me to thinking about different attributes like height. I found it interesting to know that there are different features that allow someone to be a better sprinter and better at endurance. I figured that tall people would be better at sports such as basketball but I was fascinated to find out that height affected your overall speed. It can help you reach top speeds, but being tall also delays your acceleration, which makes it harder in the first few seconds of a sprint. Short people having more endurance also makes sense. I believe height can make a big difference depending on what sport athletes play. This factor can affect the performance and it's different depending on the sports they play. I was interested in this topic, and with more research we could find out more information about how height can affect athletes and their performances.
The article, "Soccer players' head injury risk could be reduced with simple adjustments to the ball" by Purdue University, was very informative. The risk of injury that comes with sports such as soccer leads some people to stray away from the sport. The risk of getting a concussion leads people to believe that the sport is dangerous but these dangers can be avoided with simple adjustments to the ball. The statistic that 22% of soccer injuries are concussions due to the ball hitting the head is very eye-opening. It is interesting that if a ball gets wet it can be hazardous to health. Trying to decrease this number is very important for the future of sports science and medicine and this study advances our knowledge on preventing concussions in the sport of soccer. The study’s findings that a size 4.5 ball is the safest ball to play with and that decreasing pressure and limiting water absorption can also make a big difference was very insightful and important. I hope more advances to limiting injuries in relation to sports can be achieved.
The article that I read is called, “Physical Characteristics of Sprinters and Runners”. I chose this article because I enjoy running long distances, and I wanted to learn about how different the bodies of sprinters are from the bodies of long distance runners. The article shows these differences by listing several categories to compare sprinters and runners. To me, the most interesting category was the stature/height category. According to the article, for long distance runners, height does not really matter. This makes sense because the best long distance runners have varied heights. For example, Eliud Kipchoge, one of the greatest marathon runners of all time, is 5’6. Additionally, Luke Puskedra, who is another elite marathon runner, is 6’4. However, I was surprised to hear that height has little to no effect on sprinters. The article states that shorter athletes have more control and easier acceleration that taller athletes, but taller athletes have an advantage during top speed. I believe that these advantages and disadvantages cancel each other out, meaning that height does not have a significant effect on whether a person can be a sprinter. This shocked me because I believed that taller people would be better sprinters since they have longer legs and strides.
The article I read was "Physical Characteristics of Sprinters and Runners", by Dr. Liam Hennessy. It was interesting to read how the different areas of the body and different physical characteristics are important when it comes to running distance and sprinting. I knew that runners would be primarily built more in the lower half of the body, but didn't know that sprinters are actually better built in the upper back, leaving them less susceptible to conditions like kyphosis (having a hunchback). The first thing that comes to mind when talking about height and running is that shorter people are faster runners compared to taller people, as this is a well known concept. However, I was surprised to know that this is not always the case. While taller people are at a disadvantage when running uphill, as well as not being able to accelerate quick enough, they are are to keep up their top speed longer than shorter people, allowing them to cover more distance at this speed than shorter runners. This then actually disproves that notion. Another idea I found interesting was that those with bigger body mass would be able to conserve heat better due to their bigger surface area, giving them an advantage in colder temperatures, while those will less body mass would lose heat faster giving them the advantage in warmer temperatures. This article has cleared up some prior thoughts I had on the physique of endurance runners and sprinters.
The first article I read was about how little changes in the game can prevent head injuries to soccer players. I was very surprised to learn that with simple adjustments, many injuries could be avoided. One of these adjustments is to inflate soccer balls at lower pressures. Even though gameplay would be altered slightly with a less inflated ball, it would reduce the risk of someone getting hurt. I would say that this would be a great trade-off. The number of times a soccer player heads a ball is astounding, but to reduce the ball’s impact, a size 4.5 ball would be best to use. Not only should we account for the ball’s weight but the weight when it gets waterlogged. This finding has shown that a size 4.5 ball should be used instead of a size 5 ball. I hope that people realize that this is a problem that needs to be fixed so that the higher-ups will make these minor adjustments to prevent head injuries.
The second article I read was about the physical characteristics of sprinters and runners. It is amazing how different the physical characteristics are for sprinters and endurance runners. The physiology of both athletes is much more complicated than I thought. Initially, I thought that the endurance runner would have more muscle since long-distance running requires more strength overall. However that is not the case, and instead, sprinters have more muscle bulk than endurance runners. Many components decide how well you are going to perform in a sport whether it be running or pole vaulting. Many of these components include posture, stature, size, and physiology. The ability to test your fast or slow-twitch muscles is a great way to know what type of sport is suited for you. With this knowledge, many athletes can train better in a way that benefits them from the start.
This week the first two articles I read were “Concussion substitute trials to get go-ahead and FA ready to act in Cup” and “Soccer players’ head injury risk could be reduced with simple adjustments to the ball.” After reading the first article, I had to agree with the stance that permanent substitutions were the best route to go. I feel temporary substitutions make it much easier for coaches and players themselves to believe they should go back on the field after a short checkup. Taking them off the field immediately and keeping them off gives doctors more time to make correct assessments and keep them safe. In my opinion, temporary substitutions only put more pressure on medics to give the clear to get back on the field. They might feel like they could be wasting time for no reason, when in reality that time is highly important to ensuring players don’t get second impact. After reading the second article, I realize how easy it is for officials to make the game safer for players. Before reading this article, I didn’t really realize how important the ball was in causing concussions. I always assumed it was just how hard players kicked. While that still is the case, it seems like the ball is just a vehicle for the kick to do damage. If they fix the “vehicle” they can fix a lot of the problem. I was mostly concerned about how easily the ball exceeded weight limits just by getting wet. Soccer is a game where there is a lot of activity outside, meaning that it is very easy for wet ground to lead to a concussion. Officials should be seeing the information of this study and implement a system where balls are switched with fresh ones (with lower pressure) at regular increments. Dry balls are not a hard thing for the officials of a game to acquire. There is a simple solution here, and it would be ridiculous if officials did not prioritize player safety first.
The third article I read this week was “Physical characteristics of Sprinters and Runners.” Since I’m into running, this article was very intriguing to me. Concerning posture, you can definitely see that when watching professionals run. Sprinters lean heavily forward, to the point where it looks like they might fall over, while endurance runners tend to be more straight. The most interesting part of the article had to do with height. I’ve always known that height plays a role in nearly everything athletic but it was still interesting to find out that the myth that being taller makes you faster, is not entirely accurate. It’s definitely true that people with smaller heights have better control of their body weight (in calisthenics, people who weigh less and are smaller tend to be able to do more of an exercise). It also seems like being tall gives its own advantages in running. It almost looks like the specific advantages/disadvantages between the two groups cancel each other out, seemingly putting athletes on an equal playing field (at least in speed). This proves that really anyone can train for speed, and that height isn’t an excuse for performance. The last part of my article that caught my attention was the differences in muscle fibres between sprinters and runners. It’s interesting to see that our bodies are geared towards a specific type of output. It seems like, based on the chart, that endurance runners fibres act more slowly, suggesting that it preserves energy over a longer period of time. Sprinters have faster fibres because they need more explosive power. I even tried out the test of a wall reach vertical jump to see which fibres I was more likely to have. I may have not done the test properly, but I most likely fall under the high fast twitch fibre composition, which I can use in my running training.
I read the article about how different soccer balls produce less risk than other. I never knew that much research and thought went into safety for the players with a ball and I always thought it was just how efficient the ball could be. Finding out that certain balls pose more of a threat than others and that some of these could result in serious injury was a surprise to me. I also never knew soccer balls were more dangerous in the rain. I'm glad that there is research being done on every aspect of every sport as this article proves but I also see there is a long way to go. There are safety precautions being put in place that I never would have even thought. I also never really thought that there was a certain way to hit the ball with your head and always thought there was no proper form. It is reassuring that there are people out there that really do care about the young athletes and want to minimize injury but as I said I believe there is much more room for improvement and we have a long way to go.
From the prompts given this week, I decided to choose “The Physics Of Soccer” article. This article was relatively refreshing to read after reading about the stresses and hardships physicians endure last week. I chose this article not only because of my love for football(I am a fan of the football club, Liverpool), but also because of my love for math - while studying math in depth, one begins to realize its applications to all aspects of life and math truly is fundamental to many of the things around us. In relation to biology, math is used frequently in the field of research when discussing and comparing observed results with expected results - this is also known as a chi-square test and utilizes the mathematical equation χ^2= ∑(O-E)^2/E. I could continue rambling on about my love for math and biology, but I digress. Now, back to football. While reading the article, I truly began to appreciate the physics behind a curveball and how all the factors during a football field setting, including things such as wind resistance from the stadium and the kicker’s initial input of force, all contribute to the ball curving(due to the magnus effect) and ultimately leads to the ball deviating several feet from the ball’s original trajectory when nearing the net(this beautiful move makes the ball incredibly hard to predict and can even fool the best of goalkeepers.) While further reading the article, I found it amazing that all the equations accounted for so many factors on the field and that by truly observing and analyzing each equation, you could actually see how hard a professional football player would need to hit a football ball in order for it to achieve the best spin or distance possible - this shows the importance of football player’s kicking techniques and how it is actually mathematically supported that by improving one’s kicking technique, one can actually improve their kicking efficiency - this goes to show that it isn’t always the strongest football player who achieves the best results, but rather the one that works and perfects his kicking technique. All in all, I found this article truly interesting as it highlighted many of my areas of interest. Furthermore, by learning about the physics behind the game of football, I believe I can better appreciate the sport and the professional players who play it. In conclusion, I would recommend this article to anyone who enjoys math and the game of soccer, but also to anyone who wants to get into the game of soccer - this is because by understanding the small details and science behind the game, I believe people will appreciate the sport a lot more and find it more interesting.
Soccer head injury risks can be reduced by adjustments to the ball: As a person who used to play soccer a while ago, this article sparked my attention. Every sport comes with its own risks, including soccer, but I didn't know how factors actually go into making the ball itself safer for play. I didn't know how risky the effects of a soccer ball being too wet could be. What also surprised me was that the size of a soccer ball contributes to the risk of concussions and how in this study, a 4.5 size soccer ball was actually the safest. This entire article shocked me because these factors seemed so minor but can have terrible impacts if crossed to the players.
The article ‘Soccer Players Head Injury Risk could be Reduced with Simple Adjustments to the Ball’ emphasizes a long time problem of concussions that result from players using their heads to direct the ball. Until I read this interesting article, I didn’t realize how big and disregarded this problem was even though it had the biggest consequences to the human body, like potential neurological changes. I was unaware of the research done to prevent such extreme injuries, which recommended inflating balls to lower pressures, which could reduce the force of the blow to the head by 20% and subbing them out when they get wet. But it can also be dangerous if the ball gets in contact with too much water because it eventually gets too heavy to play with since soccer is also played during the rainy season. As far as I knew, soccer balls were waterproof and didn’t get affected by water, but now, I came to know that soccer balls can get waterlogged and lead to extreme injuries. This research is important for soccer players to know because a single professional player heads the ball 800 times over the course of an entire season on average because it can provide an easy way to prevent the risk of head injury.
I read the article “Concussion substitute trials get go ahead and FA ready to act in Cup”. By permanently substituting players who had a concussion, it allows more time for a better diagnosis. But, using only a temporary substitution could be detrimental to the athletes, if they actually had a concussion. The article “Soccer players’ head injury risk could be reduced with simple adjustments to the ball” is about the impact of headers. When the soccer ball hits the head with too much pressure, it causes neurophysiological damage. I was really surprised by this research, by the damage that headers inflict. Both of these articles display the need for safety, better protocols and better equipment in soccer fields.
I read the article “Soccer players' head injury risk could be reduced with simple adjustments to the ball” published by Purdue university. I was surprised when I learned that almost 22% of injuries that soccer players have to deal with are a direct result of heading the ball. The sheer amount of times that players will head the ball in a season or even a singular game is truly jaw dropping. The soccer ball has to fit into very specific restrictions to be viable in game but even if something about the ball is off, such as if the pressure is off or if the ball is waterlogged, then an injury is almost waiting to happen. When the ball is kicked and a player heads the ball, the amount of force played due to the impact can be detrimental to the wellbeing of players. Despite all of these different negatives of performing a header in game, there are more safer options than using the current sized soccer ball. If leagues around the world change the size of the ball from a size 5 to a size 4.5, the sheer impact felt on the players’ heads will be less thus creating a much more injury free game. There are always going to be numerous innovations in the way sports such as soccer is played making the game much safer for the player.
This week I read, “Soccer players' head injury risk could be reduced with simple adjustments to the ball”. I was surprised to read about how preventing serious head injuries had a simple fix. A new study suggested that lowering the pressure that the soccer balls were inflated at could prevent a large amount of head injuries in soccer (about 20% of injuries). The one catch with this is that if the ball gets too wet, it could go over the weight limit, and cause more injuries. Even though velocity is the biggest factor when it comes to the extent of an injury caused by a soccer ball, ball pressure and water absorption are the easiest to manage. This article also provided a great example of the scientific process. The researchers first had a question in mind, if the size, pressure, and water absorption affect the strength of a soccer ball when hit to the head. Then they created an experiment that tested how safe 3 types of soccer balls are. For each type of soccer ball, they modified certain factors such as water absorption and air pressure. At the end of the experiment, they found that the safest ball to play with was the size 4.5. Although professional soccer players do not use size 4.5 balls yet, I think that with more research, changes will be made to the game.It is great that such a simple change can benefit so many players.
Reducing head injury article
I am not very involved with soccer, so I don’t know much about it. However, if reducing the risk of head injury for soccer players relies on actions that stay within the current parameters of soccer balls, then it seems like a no-brainer to take these steps to reduce head injury. I was unaware that such a large percentage of soccer injuries are concussions. I also did not know that water absorption played a role in the risk for head injury from a soccer ball, nonetheless such a large one. The study about this seemed very conclusive, so I would assume that the findings would apply in the real game.
Sprinters vs. distance runners article
To begin, my previous knowledge of sprinting and distance running is limited. Posture is an area that is intuitive to be drastically different between the types of runners. The article mentions that height does not seem to play a role in distance running, as size does not make a difference at a constant running speed. This surprises me, because the specific form required in running would make sense to have an optimal height. Overall, this field of study is fascinating, and the depth at which differences can be found between distance runners and sprinters is remarkable.
“The Physics Of Soccer”
Before reading the article, I decided to watch the video, and it was amazing how the Magnus Effect (which I had never heard of before) could be so powerful that it could lead to an object somewhat resisting gravity. In addition, while reading the second paragraph, I realized that the Magnus Effect is used in sports other than soccer. For example, in tennis and ping pong, top-spin can be added to a ball to make it harder for the opponent to get (which my dad can and does do to me), but I never knew the physics behind it.
“Physical Characteristics of Sprinters and Runners”
If you asked me whether I thought sprinters or endurance athletes had more muscle, I would have said endurance athletes because they spend more time performing their sport. However, surprisingly, the article shows how this is not the case. In addition, I was surprised when I learned that being an endurance athlete such as the long distance runner can lead to developing some kind of kyphosis, or that being a sprinter can lead to developing lumbar lordosis. This is because I never realised that posture and what type of athlete you are could be related. The mitochondria content being higher for slow-twitch fiber versus fast-twitch fiber made sense to me as an endurance athlete would need more energy than a sprinter to last longer in their sport.
The mechanical function section of the chart comparing the slow-twitch fiber versus the fast-twitch fiber also made sense to me. This is because sprinters would need a higher contraction speed, relaxation speed, and force generation due to them needing to run faster than the average endurance athlete. In addition, a slow-twitch fibre providing an endurance athlete with less fatigue than a sprinter (as stated in this section) made sense as if endurance athletes got tired out too quickly they would not necessarily be ‘enduring’ anything.
Physical characteristics of Sprinters and Runners: For some reason, before I read this article, I believed that taller athletes would make faster runners. Maybe it was the fact that they had longer legs which equated to a longer stride and therefore would take them less time to reach the finish line compared to a shorter athlete. However, reading this article surprised me as I learned that the stature of taller athletes puts them at a disadvantage. It takes longer for them to accelerate as it does down for them to run uphill. Further thinking about this does make sense to me. Shorter athletes have less mass meaning they would take less force to accelerate (haha physics), and there might be an aerodynamics component too. Something that I found especially interesting too is that sprinters and runners have a special fast-twitch fiber, something that other athletes lack, that helps them move faster. These specific muscle fibers burn energy more quickly for only a short period of time which allows runners to run at extreme speeds over short distances, while slow twitch muscles burn energy more slower over longer periods of time, which would favor endurance athletes. In the end though, the amount of training athletes go through in order to prepare their bodies, down to the muscle fiber, astonishes me. It's incredible to see how much effort goes into training and preparing for such events, as well as the dedication.
The article I decided to read about this week was, "Physical Characteristics of Sprinters and Runners." From the first glance at the title, I knew that this article was very intriguing. Since the beginning of high school, I have taken part in track and field for both winter and spring and now cross country. During the track and field seasons, I do sprints. Subsequently, during the off-season in fall I do cross country, which requires a different set of skills. It was very intriguing to learn more about the posture difference between long-distance and sprints. When you sprint you have to look forward and arch your back inwards to the point where it looks like you're about to fall and then gradually bring yourself up correspondent to your speed. In contrast, when you have to run longer distances you need your posture to be straight so you have the optimal conditions to run in. The height and stature of a typical sprints team can be different, and all the heights are varied, with not a specific group doing better. In cross country, this tends to differ, because during the hill stretch of the map pushing yourself up the hill, tends to be easier for shorter stature people. As you look at the graphs comparing the muscles of both types of runners the main trend seems to be that the element remains present in one type of runner, but not the other. This is because the training and skills required for both athletes are different. For sprinters it is necessary to get a good start thrusting yourself up, this means that the upper back and shoulder muscles will be stronger. In addition, this also means that the fast-twitch (reaction time) will be better as well as the relaxation speed. Distance runners have a bit of a difference with these terms. Since these runners maintain a simple straight posture, their shoulder and upper back muscles will be quite weak. Subsequently, their leg and core muscles will be stronger as they continue to push themselves to run many miles at a stretch. This means that they will have more stamina, and get tired less quickly. Overall, these athletes tend to be varied, both of which require immense skill.
I read the article "Soccer players' head injury risk could be reduced with simple adjustments to the ball". Being someone who enjoys watching and playing soccer, it hurts to see good players get sent off because of an unexpected injury. The article describes a study conducted by engineers at Purdue University, who determined that adjusting certain forces that cause a soccer ball to be heavier, such as pressure and the amount of water in the ball, can reduce potential head injury by 20%. Professors Eric Nauman and Francis Shen studied a multitude of statistics regarding soccer balls and head injuries. They found out that the average professional soccer player heads the ball 12 times per game and 800 times per season. As Nauman says, if a player heads a ball with higher pressure, it could be extremely dangerous. The two professors conducted two experiments: one involving pressure, and the other involving water. For the first experiment, the scientist tested the amount of force when sizes 4, 4.5, and 5 balls are kicked, with the balls having varying amounts of pressure. For the second experiment, they placed each size soccer ball in water for 90 minutes, weighing them every 15 minutes. Their results led them to the conclusion that a size 4.5 ball would likely be the safest. They aim to continue to examine the factors that cause a soccer ball to be unsafe to head. This article stuck out to me because I am a fan of Liverpool FC, and our club suffered a large amount of injuries last season. It would be great if soccer players could one day head the ball without risking their safety.
In “Concussion substitutes trials get-go ahead and FA ready to act in Cup”, it is discussed how the IFBA has now permitted 2 concussion substitutions per team per match. As someone who plays soccer, I think that this was a smart move considering how many professional soccer players use their head to gain control on the ball. There is a right and wrong way to head the ball and it is not difficult to end up with a concussion. It is also common that when two players go to head the ball at the same time that they end up colliding, possibly resulting in a concussion. It is a better option with these substitutions for the sake of the health of these players. Although players of this sport may not seem prone for neurological damage, it does occur and because of that, it is extremely important for players to get the medical attention they need when the risk of neurological damage is present.
The article, “The Physics Of Soccer”, made me realize how science impacts every portion of our lives. When kicking a soccer ball, physics is utilized. The Magnus Effect is the curve of the ball when in the air due to friction between the ball and the air. If a player kicks the ball left, the Magnus Effect will curve the ball right. The equation that relates the initial and final velocities of the colliding bodies is utilized for kicking. Reading this article made me realize how much science is utilized in our daily lives. Although I was aware that science is all around us, it gave me a new insight on how science really affects things in life that most people don’t think about.
I read the article, "Soccer players’ head injury risk could be reduced with simple adjustments to the ball". As someone who played soccer, my parents constantly worried that I was going to get hurt during games and thought I would suffer head injuries if I wasn't safe. It's quite ironic that I did in fact get a concussion and get injured multiple times over the course of my athletic career. However, reading this article made me happy that steps were being taken to keep the players safe and adjust rules and guidelines to avoid injury.
I read the article, "Soccer players’ head injury risk could be reduced with simple adjustments to the ball". I was surprised to see that as many as 22% of soccer injuries are concussions from headbutting the ball. I used to play soccer throughout middle school and elementary, so when I found out headbutting a wet ball was like headbutting a brick, I was shocked, to say the least. Even though soccer committees regulate the air pressure of soccer balls, there is still a high risk of playing soccer.
I read the article about how soccer players’ head injury risk could be reduced with simple ball adjustments. I had not known that soccer players would hit the ball with their head very often (up to 800 times a year and twice in one game). I had thought that it was one of those rare and kind of under moves in the game. Hitting a soccer ball with your head has always looked uncomfortable, but I never imagined that it would feel like hitting a brick if certain conditions of the ball were met. The ball can be too wet or the pressure of the air in the ball could be too high. There is also the issue of how these conditions can change with different soccer ball sizes. One would think the problem of hitting the ball with ones head would be hard to solve since there are so many uncontrollable factors when it comes to receiving a soccer ball. But I was surprised to find out that all it took was a simple experiment where different pressures and amounts of wetness of the surfaces of soccer balls were hit against a pressure plate until a good amount was discovered. I think it is very clever how simple adjustments can result in much safer game play. This situation truly shows how science can be used in different ways to make small changes in our lives, resulting in a better and safer world.
“Concussion substitute trials get go ahead and FA ready to act in Cup” - With it’s fast pace, fascinating technical skill, and elaborate plays, soccer has never ceased to amaze me. Ranking in at 6th most dangerous sport according to “Bleacher Report,” soccer never fails to keep players and fans alike in fear of what may happen. To keep the beautiful sport exciting and nail biting while also keeping players safe, concussions substitutions should be made for each concussion for a permanent time per game. Believe it or not, players should be looked after because at the end of the day, a healthy and able player is better than a player who plays through a concussion with the chance of permanent or fatal problems. Concerns about permanently removing a player may include a limit on playing time, less chance of proving a players capabilities in a large setting, or just the societal outburst that could take place if fans see their favorite players out of a game. While these are valid concerns, the health of the players should be the biggest concern. If the players injure themselves farther through temporary breaks and a limit on concussion substitutes, they could very well be out for more games, a whole season, or even permanently have to put soccer aside. It has been said by medical experts themselves that the time in between a game is just not long enough to tell the effect of a concussion or what can happen from it. Keeping these things in mind, trail 2 would have to be the best response to concussion substitutes. Of course limiting the number of headers done at practice is crucial, it can’t be the only thing being done to prevent concussions and keep players healthy for a longer period of time.
“Soccer players head injury risk could be reduced with simple adjustments to the ball” by Perdue University - Following with the same idea of lessening the amount of strain a soccer player’s head endures through concussions or similar head injuries, this article presents a plausible and innovative solution to the issue at hand. Inflating balls to lower pressures and switching out wet balls is not only an easy fix, but it is also effective according to the scientists at Perdue. Velocity of the ball when being hit seems to be the real reason for the 22% of head related injuries, but if that can’t be changed others things should be done. While this seems like an easy fix, I'm not sure it can be implemented just yet. The idea of switching out wet balls to keep them properly weighted may be easy, but lessening the pressure in standard soccer balls is hard to do. Speaking from personal experience, a ball has to be inflated perfectly to allow the best results. A ball that is a little flat is considered “unusable,” because it throws off a soccer player's kick rate, speed, and timing. I do think that both of these ideas should be implemented for 4 and 4.5 ball sizes. The results showed close to the same results and if switching out wet balls and alleviating ball pressure for children under 12 is effective, it should be done to cause less traumatic experiences in less competitive settings. While I think the idea is still useful and innovative, I’m not sure it is the best course of action from a players perspective.
I read the article, “Soccer players' head injury risk could be reduced with simple adjustments to the ball,” by Purdue University. I am not a huge sports or soccer fan, but I do watch a few major games from time to time. I have always noticed how much players could get hurt by their moves. They always perform dangerous movements to ensure their win in the game and end up getting hurt because of it. I had always thought that the players poor moves were the reason for their injuries, but this article suggested another reason. It states that the ball pressure, size, and whether they are wet or not, affects soccer player injury. In the games I have seen, soccer players hit the ball with their head multiple times in various angles. Had the ball been different according to certain conditions shown by this research, the hits would have been much less painful than described by the announcers. My brother had previously played soccer, and he had stated that if the ball has a higher velocity, it hurts more than if it was coming slower. This is a factor that cannot be controlled during a game, but others could be to reduce injuries. I think that soccer governing bodies should take research like these into consideration when making their regulations. Small things like this could completely change a players injuries in the game.
I read “Physical Characteristics of Sprinters and Runners” and was informed about the remarkable differences between endurance runners’ and sprinters’ bodies. I assumed that sprinters would be more muscular in their calves and upper arms, whereas long-distance runners would be more lean. The article confirmed this and goes on to describe how these different body types help or hinder specific types of runners. I figured that taller people would be better runners overall since they have longer legs, but surprisingly, studies references in the article assert that tall and short people have equal advantages and disadvantages that makes height a negligible factor when concerning speed. This also seems to be the case when regarding size, where bigger and smaller people have their own sets of advantages and disadvantages. I knew that larger people would be stronger and have more arm strength that would allow them to accelerate faster because as the article says, their bigger arms will provide more torque. However, smaller people also have an advantage in maintaining control of their mobility, using gymnastics as an example of how this is useful. They are also able to let off heat, which is useful in endurance events, but not in cold weather. The article then describes the physiological differences between sprinters and endurance runners. It was interesting to learn that there are two different types of muscle fibers, slow twitch and fast twitch, which is probably a key variable in a runner’s ability to sprint or endure. I predicted that sprinters would have more fast twitch fibers because their legs need to speed up faster, and endurance runners would have more slow twitch fibers because they need to slowly gain speed and maintain it for a while, and the table confirms this. All in all, it was interesting to read about the many different physical factors runners must acknowledge when training their body to be at their desired performance.
Physical Characteristics of Sprinters and Runners: I chose this article because I run long distance and wanted to learn more about how a sprinter's body differs from a long-distance runner’s body. The article illustrates these distinctions by comparing sprinters and runners in a variety of categories. The height category piqued my curiosity the most. According to the article, height is unimportant for long-distance runners. This makes sense given that the top long distance runners are of varying heights.This is interesting as I would have thought height plays a key role in distance running, in general. Shorter athletes had more control and easier acceleration than taller athletes, according to the article, while taller competitors had an advantage at top speed. All in all interesting topics were discussed, and as a runner myself I feel educated on how i can improve my timings for upcoming races.
This week I read the article “Physical Characteristics of Sprinters and Runners.” Naturally as a runner, I was instantly drawn to this article and wanted to find out more. The article discusses how the physique of an endurance athlete and a sprinter would be considerably different. As a distance runner and a sprinter, I wondered how this would apply in my situation. Posture plays an important role in running. However, as a sprinter it matters more due to the way sprinters start low and push out upwards. Meanwhile, a distance runner usually maintains the same stature throughout their run. This is mentioned in the article when it talks about how the upper back and neck area would be more developed than an endurance athlete. Something that surprised me however, was the fact that taller athletes are at a disadvantage when running uphill. I had always assumed that it would be easier for them because they would be able to take longer strides. In the future, I would like to do more research on this and figure out why. The experiment in the article further discussed the key differences between a sprinter and an endurance runner in Table 2. Table 2 shows how there are a greater number of sprinters that have a fast twitch than a distance runner. However, there is still a small percentage of distance runners who have a fast twitch which makes me wonder if they play other sports that may possibly affect this.
This week, I read “Physical Characteristics of Sprinters and Runners”, in which I learned about some of the most prominent differences between sprinters and endurance athletes. The main difference between the two is the distance they run- sprinters often run short distances at faster speeds, while endurance runners run long distances while pacing themselves. One thing I found very surprising while reading this article was the fact that endurance runners are generally lighter and have less muscle in their body, compared to a sprinter. Initially, I had thought that endurance runners would have more muscle, since they have to run longer distances, but that is not the case. In addition, I was also very surprised when the article debunked the myth that being taller helps a sprinter run faster. Since she got onto the school’s track team, my sister has constantly said that some of her peers can effortlessly run faster simply because they are taller. To a certain extent, I even believed that having longer legs can help improve the speed of a runner, however, reading this article helped me understand that being taller has no influence on a runner’s speed. In fact, being taller can even be a disadvantage in some cases, such as when the athlete is running uphill. In addition to height, I learned that a variety of factors affect a runner's ability to perform in these activities, such as their posture, size, and physiology.
This week I chose the article “Physical Characteristics of Sprinters and Runners”. As someone who’s ran for a good amount of time, I thought this article would be interesting. Before reading, I knew that sprinters were typically more muscular compared to endurance runners. Endurance runners typically have a smaller build. Reading the “Posture- difference between sprinters and endurance athletes” section intrigued me. I had never realized how many internal differences there were regarding the build of runners. Being 5’7, I have always questioned whether being tall was an advantage while running. People always expressed it as one to me, saying that it helps open up your stride and take fewer steps. In my opinion, I don’t think being tall or short is an advantage while running because there are benefits for each height. Similar to height, I think certain key strength and power factors are not necessarily beneficial. Being tall could help you in the discus turn, but be difficult in gymnastics. The last section of this article was based on physiology. Reading this table, I was curious to what the components meant regarding running. Due to the names, I could tell that slow twitch fibers were used for endurance runners with stamina and fast twitch fibers were used for sprinters with high speeds. This table developed a common pattern. In most topics, slow twitch fibers were “low” or “slow” and high twitch fibers were “high” or “fast”. The second table, “Fast twitch estimations for athletes from different sports” didn’t surprise me. The 100-200m had the highest percentage of fast twitch women and men. Distance runners had the lowest percentage of fast twitch women and men. Overall, this article truly differentiates sprinters and distance runners, showing that being able to sprint does not mean you are built for endurance runs and vice versa.
I read the article, “Physical Characteristics of Sprinters and Runners” by Dr Liam Hennessy. I chose this article because I enjoy running and wanted to learn about this topic. After reading this article, I understood that physical features play a big role in your running ability and speed. I was extremely surprised by the fact that being tall is a disadvantage when running uphill and when it comes to acceleration. This is because I have always heard that taller people are usually faster because of their long legs. Also, since I am taller, I always thought I had an advantage while running. However, I learned that shorter athletes can accelerate and control their body easier while running. This was shocking to me, but also very intriguing. It is amazing how your body characteristics can affect your running ability in so many ways.
I read the article titled, “Soccer players’ head injury risk could be reduced with simple adjustments to the ball”. Something interesting I learned was how the size of the soccer ball is actually important. The article states that the size of a soccer ball can impact the risk of getting a concussion during the game. I found this shocking because I thought that there would be other factors of the game that would lead to concussions instead of the ball, such as the condition of the grass. I assumed that the condition of the grass and the footing of the player were the main factors that lead to a concussion. Throughout the whole article, the author continuously proves how small factors can lead to unfavorable outcomes for the players during the game. For example, the soccer ball has to fit certain standards to be suitable for the game. The ball has to be tested to make sure that there won’t be a problem with it or else even a small error may result in serious injuries for the players. The article states that if the general rules of the game changed the ball size from size 5 to size 4.5, then this may help reduce the number of head injuries. What shocked me was that soccer leagues haven’t made any attempts to change the rules to make the game safer. The article also states that there was a study that showed that lowering the pressure of the inflated soccer balls could also prevent several head injuries yet there are no changes being made to accomplish this. This change may also lead to a risk of causing even more injuries because if the ball gets too wet, it may go over the weight limit. Though there are risks to making these changes, I believe that they should go forth with these changes if they can potentially decrease the number of injuries.
Article I chose: "Soccer players' head injury risk could be reduced with simple adjustments to the ball."
Whenever I would play soccer with my friends and use my head, I would immediately regret doing so because it is pretty painful. This personal experience had made me wonder why it was so painful and was it safe to do it. After reading this article, though, I gain a significant amount of insight on how dangerous it is to use your head in soccer and the factors that make a soccer ball painful to use with your head. I found it shocking that 22% of soccer injuries are concussions related to players using their heads. This statistic might seem low, but this is a pretty significant number for a sport that consists of many injuries. Another fascinating thing the article brought up was the factors that affect how hard the ball is, ultimately correlating with head injuries for soccer players. These factors consisted of pressure, size of the ball, and wetness of the ball (there was also velocity, but it is extremely difficult to change that). Knowing that soccer organizations are now taking these factors into consideration makes me happy because now they are helping reduce the concussion rate for players and making the game fun and safe sport to play. Hopefully, more researchers like the ones in the article start following up on this research to decrease the rate of concussions significantly in soccer to ensure the safety of any athlete that plays the sport.
The article I read this week was "The Physics of Soccer" and its fascinating how much spin a player implements on a ball so it can curve or reach a certain position. Though I am not much of a soccer fan, I do find physics quite exquisite and I do enjoy processing new equations. The magnus effect can also be applied to numerous of other sports such as baseball (hitting the ball with a bat from a certain angle), tennis (having topspin), and golf (hitting the ball from a certain position). It was easier to comprehend what the author had to say with the numerous diagrams that were provided for the reader. When watching the video, towards the end, one of Kyle Kitzmiller's attempts for curving the soccer ball hit the net post twice and it was anonymous to why it happened. But after taking some thought into into, I developed a predicition and think that after he kicked the ball, the amount of kinetic energy remained significant on the ball and because it hit the net post the first time on an upwards angle, it must've bounced up (on the same angle) and hit the net post a second time, causing gravity to then do its thing. I'm not entirely sure but I thought a lot about it and used the equations very minimally for some sort of reference. But after reading the article, I approached a much better understanding of the magnus effect and I'll admit, I did gain a small liking for soccer after reading this information text.
Amanda Vaysbukh
The article “Soccer players' head injury risk could be reduced with simple adjustments to the ball" was quite interesting to me as I did not realize how regulated the ball used in professional soccer games actually was. In fact, after reading the article I agree there should be more testing completed to improve regulations. Weather, an uncontrollable factor that effects our lives is so impactful on soccer player health. Although weight and size of a soccer ball are regulated by professionals, that all goes out the window if it begins to rain. I did not realize a soccer ball even absorbs water, let alone have its weight change so greatly due to water absorption. However, the article explained that we can improve athlete safety if regulation improved in terms of water absorption in soccer balls. However, this just points out the underlining issue of the lack of improvements done in the soccer world when it comes to athlete safety. If more testing was done, there would be less concussions. That being said, concession check for athletes needs to be improved as well. We shouldn't be focused on if the athlete can play rather, we should focus on the athletes health. This is further exemplified in the article titled "Concussion substitute trials get go-ahead and FA ready to act in cup". The article discusses the amount of substitutes there should be per game when it comes to concussions. The article briefly mentions how concussion symptoms can show up even 72 hours after initial impact. Concussion checks completed by medics can be incorrect if the athlete is yet to be symptomatic, therefor the athlete will continue to play, possible worsening the condition. If permanent substitutes were included the player's health would be in less risk. The rules in sports are constantly changing for professionals so lets make the changes in soccer to improve athlete safety.
I read the article, "Physical Characteristics of Sprinters and Runners." Although I do not follow many Olympic sports, I have seen highlights of some track events. I noticed that for the shorter events (like the 100 m), the athletes would explode from the beginning until the end. Yet, for the longer ones (like the 200 m), they would start just a little bit slower and accelerate much faster. I did not attribute this difference to height and stature, but this article proves they can be factors. For instance, the author writes, "When it comes to flying or the top speed, taller athletes may have an advantage." The author later describes how these two can be a factor in other sports, including gymnastics and pole-vaulting. However, I think height does not matter for some sports. The only sport I do is Taekwondo, so I will talk about that. When two athletes are sparring, they should be in the same weight class, but their heights may greatly vary (I fight mostly against people much taller than me). If the athletes are positioned further apart, the taller one has a much better chance of scoring. Still, the shorter one will try to close the gap to score. This strategy is seen in the featherweight division of the Women's Olympic match. In the final round, Anastasija Zolotic fought against Tatiana Minina. Anastasija had longer legs and was able to kick Tatiana more (especially in the head). However, if you look closely, you can see Tatiana inching closer at times to score because she is shorter. Anastasija did win the match, but Tatiana put up a great fight despite being shorter than her opponent. Thus, one of the reasons I love Taekwondo is because you do not have to be tall to fight well; you just have to know your opponent and know your strategy.
Personally I am not the biggest soccer fan, however I run track and field for the school and the "Physical Characteristics of Sprinters and Runners" article caught my attention. I know that as a daily runner I need to work on my leg muscle endurance. I run the 400 meter and the 200 meter in track which means that I have to use fast-twitch muscle fibers in order to run as fast as I can for a short period of time. Fast-twitch muscle fibers tend to be found in sprinters because they can provide more power at a quicker pace for a shorter time lapse. On the other hand, long distance runners often have skinny legs which can handle more endurance at a slower pace. Long distance runners tend to have slow-twitch muscle fibers, which are the prime opposite of fast-twitch muscle fibers. Therefore when reading the chart about the characteristics of the two types of muscle fibers, all of the pieces of the puzzle started to come together.
The article "Soccer players' head injury risk could be decreased with simple ball tweaks" piqued my curiosity because I was unaware of how tightly regulated the ball used in professional soccer games was. With the multiple graphics supplied for the reader, it was simpler to understand what the author was saying. When watching the film, one of Kyle Kitzmiller's attempts to curve the soccer ball twice struck the net post, and the reason for this remained unknown. I never knew about how much the physics and science plays in professional play for all of these athletes. In this article I was able to learn all the different ways the ball is affected when playing soccer.
In the first article I've read "The Physics of Soccer" and I found it the most interesting since soccer players have to take in many things when they need to kick the ball in a perfect way. Firstly, the ball spins in flight after you kick it. There are also many other factors you need to take into consideration, like the air pressure, the downward force, and velocity. The path curves while in flight and shows how much physics is important when you want to calculate where exactly the ball will land.
The second article I've read was "Soccer Players Head Injury Risk could be Reduced with Simple Adjustments to the Ball". I already knew concussions in sports were an issue but not how devastating they can be on the human body. I assumed many of the injuries were from players injuring each other but not the ball causing injuries. The first thing the article says that must be done is to deflate that balls which makes sense since it will not be as hard of an impact when you hit the ball with your head. They also said that the ball should be replaced when wet which surprised me because I did not think that a wet ball would increase the impact made. Also the size of the ball matters, a size 4.5 ball is much safer to hit than a size 5 ball. More testing still needs to be done to conclude the best precautions to be taken in order to prevent more concusions.
- Arsalaan Zaki (Late Comment)
Article: Physical Charteristics of sprinters and runners
I only picked up this article because I've picked up bodybuilding and am interested in what body types are result from proficiency in certain activities (ex. people who powerlift have high levels of bodyfat). WHat I noticed is that there were considerable differences in the amounts of fast-twitch and slow-twitch muscle fibers in sprinters and runners, with sprinters having double the amount of fast-twitch muscle fibers as runners (fast-twitch muscle fibers are the muscle type targeted by bodybuilders in their main trainings because they are much larger than slow-twitch fibers). I related this content to previous information by learning that sprinters usually had a lot more muscle mass and upper body strength compared to runners, seeing as doing something completely different than lifting weights had still given them a body with similar physiological development as what could have been achievable doing resistance training. I was interested to learn the reason as to how this sort of development was reached by sprinting, and if it could be from sprinting alone, or a resistance training program in tandem.
Post a Comment