Speed Isn't Everything: Tennis Serve

In sports such as baseball and tennis, athletes tend to improve on pitch speed and serve speed. And it is important to have enough speed, however, it may not be everything you need to have when it comes to professional sports. We analyzed more than 200 match stats from this year's Grand Slam (Australian, French, Wimbledon, and US opens). We have found that the winners' average 1st serve speed was about 183km/hr and also that the losers served about 183km/hr on average. The 2nd serve speed was 149km/hr for the winners and 148km/hr for the losers. What was different between winners and losers were that the winners won about 77% of their 1st serve and the losers won only 65%. Also the winners won 56% of their 2nd sere points and the losers won only 45% of them. This tells us that serve speed was not everything in those Grand Slam matches. There has to be something else that matters other than the speed. Ball location, serving strategy, and ground stroke, etc etc. This just tells us that serve speed isn't everything in tennis and probably the same for sports such as baseball at least in a professional level.

Gravity in Sports

Most people do not like physics and chemistry and math and.... all those things we all learn in school. Most of us wondered why we had to learn all that. Sometimes knowing a little about physics won't hurt us..... Yes! Even in sports! We all know what the gravity is and all know that it exists every where we go on Earth. And it's constant everywhere. And it is FREE to use!! The gravity can be your best friend or your enemy. It depends on how you use it. When we do rehabilitation and exercise, we think about the gravity all the time to effectively and efficiently use it or to eliminate it. Let's say you are being measured for a max vertical jump. When you are standing straight on the ground, you are experiencing something called ground reaction force (GRF) which is the same as your body weight. Your weight pushes down on the ground and the ground pushes you back up. That's why you are not sinking into the ground or you are not being pushed up in the air. How high you can jump depends on how well you can use GRF. How well you can maximize it and how efficiently you can use it. Athletes with more weight potentially have more GRF they can use because GRF varies with body weight. However, they have to be stronger to be able to jump because they are heavier. So how can we maximize it? Stand on a scale and see how much you weigh...staining straight...and then try moving your arms up and down or bend your knees. You should see the number of the scale go up for a moment. That's one way to jump higher. Use your legs and arms. Another way to do that is to do a little hop before you jump up (this is usually not allowed when you are being measured though). Any object in the air has something called potential energy and it depends on its mass and its height. When you hop straight up before you jump, you are creating an extra energy that you can use because when you land from the hop, GRF is higher. Try hopping on a scale (without breaking it) to see what happens when you land on it. However, a flip side of this is that when you jump you have to land too. The higher you jump, the bigger the force your body feels and needs to absorb is. A good thing is that you have shock absorbers in your own body...muscles. Muscles are like springs. They can create a force for you to use and can dissipate it. A lot injuries happen during landing and its cause is multi-factorial. A failure to absorb a force when you land will put stress in your body (joints, muscles, bones, etc) If you do not land in a right way, your body will feel extra stress that you may not feel when you land correctly. Over time, it could lead to an injury. You also have to have enough muscle strength to do it. You need to have right muscles working at the right time too. Bad mechanics will interfere with it. Especially in sports where jumping is a major part of, it becomes even more important to be able to utilize the gravity and also able to protect your body from it. Gymnastics, volleyball, figure skating, basketball, etc etc etc. Hope this makes a little sense. The gravity can be your best friend or can be your worst enemy. But it is up to you to make it your BFF!!!

Stress Fracture in Figure Skaters

This figure skating season is nearing an end as only a few more international and national level competitions are left. Also, this is about time of the season when athletes get injured as an intensity of competitions increases. Those skaters who qualified for the nationals are probably training harder to do well in the competition. Some may be trying to secure a spot at the Worlds. Or some may already been training for the next season. Training hard is necessary to be successful. However, training too hard can be potentially damaging to the body. One of the common injuries suffered by figure skaters is stress fracture. The common injury sites are foot, lower leg, hip, and lower back. Stress fractures are categorized into 2 categories. One is a high risk fracture and the other is a low risk fracture, depending on where the fracture is located. High risk fractures are treated more aggressively because of their higher chance of non-union fracture. Many cases may require a surgical fixation of the fracture. Low risk fractures are usually treated with relative rest, partial or non weight bearing, activity modification, and rehabilitation. In case those do not work, then, it may be treated more aggressively. One of the reasons why it makes it challenging is that a lot of skaters will ignore a pain and keep training until it gets to the point that they cannot. By the time it becomes that painful, it may be too late. Once diagnosed with a stress fracture, a skater will be off the ice for a long time, probably around 6 weeks to a few months. Good news is that it is preventable. Causes of stress fractures include sudden increase in training intensity and time, a change of skates, nutritional factors, over training, not having proper mechanics, etc to list a few. Female skaters are more prone to stress fracture than male skaters. A study done at BYU showed that figure skaters sustain about 8 times of their body weight when they land on ice from a jump. That means that they have to be able to sustain that much force only using knee and hip muscles (and core muscles play an important role as well). When we jump and land on the ground, we can use ankles, knees, and hips and muscles around them to absorb the force. However, when skaters jump on ice, they are forced to use only knee and hip because of rigid type skates they wear. It becomes very important that they have enough muscle strength in their knees and hips to sustain that much force. By being evaluated for any risk factors they may have and by eliminating those factors when they are healthy, injuries such as stress fracture can be prevented.