The Stephen Strassburg Debate

If you are a major league baseball fan, then you have probably heard that the Washington Nationals plan on shutting down their ace pitcher, Stephen Strassburg, after he pitches around 170-180 innings this year.  What is their rationale for doing this?  Strassburg is a young pitcher, and he had ulnar collateral ligament reconstruction surgery (Tommy John surgery) a little less than 2 years ago.  Their theory is that by limiting the number of innings he pitches in his first full year of pitching after the surgery, they will help prevent him from becoming injured in the future.  Is this the right approach to take? 

The Argument for shutting him down: There is no doubt that the overhead throwing motion used by baseball pitchers places a lot of stress on the shoulder and elbow.  Most of these pitchers begin pitching at a relatively young age, and the cumulative stress of every inning pitched, bullpen session, and warm-up throws can lead to a degradation of the soft tissue of the shoulder and elbow.  A torn UCL is often times not the result of one traumatic event, but an accumulation of small tears in the ligament that cause it to weaken over time and eventually rupture during the execution of a pitch.  Also, labrum (the cartilage lining of the socket of the shoulder) tears in pitchers often occur due to the repetitive stress placed on the joint from throwing thousands of pitches.  This is why the Nationals want to shut Strassburg down.  He is relatively young, he already had one major surgery, and has the potential to win many games for them in the future.  By shutting him down early, they will help prevent excessive stress from being placed on his arm, and they are counting on this to keep him healthy in the future.

The Argument against shutting him down: From a purely baseball prospective, the goal is to win as many games as possible, make it into the playoffs, and win the World Series.  The Washington Nationals are not a franchise rich in postseason history.  This is their best chance to make it to the World Series.  The franchise has only been to the playoffs one time in their history.  Strassburg is one of the best pitchers in baseball, and to have a good chance of winning in the postseason, you really need your best players to play.  Also, there is no evidence to suggest that by shutting Strassburg down, he will not have a major injury in the future.  There have not been any studies conducted to investigate this question.  Also, Strassburg recently had his UCL reconstructed, so at this point, it should be very strong.  The Nationals should have a good team for the next few years, but in sports, you never know how many chances you are going to have to win a championship.

What would I suggest?  If it were me, I think I would continue to let him pitch, but would closely monitor his pitching mechanics for signs of fatigue and breakdown.  If Strassburg started to make changes to his throwing motion because he was fatigued due to all the pitches he has thrown this season, I would consider shutting him down or giving him a break.  The Nationals could also limit his innings over the last few weeks of the season so he could pitch a few games in the postseason without throwing an excessive number of innings.  However, you have to admire the Nationals organization for taking a pro-active stance on the number of innings they are going to allow him to pitch.  It seems like a majority of the time teams place winning ahead of player safety (especially football), so it is refreshing to see a team take a stand like this.  Hopefully it works out for Strassburg and he is able to have a long and relatively injury free career.  Even if Strassburg does not sustain another major injury for the rest of his career,  it will not be possible to cite his shutdown this year as the cause.  There are too many factors that effect whether or not an athlete sustains an injury to credit one singular event.

First day of classes

Today marks the first day of classes at Mississippi State University.  The first day is always an exciting time, and probably scary for some of the students.  I was talking with my wife the other day, and since we both started Kindergarten at age 5 back in 1987, we have either been in school or working at a university for the past 26 years.  We both love our jobs and interacting with the students.  I tell all my students that I want them to be successful and will do anything I can to help them succeed. 

I am teaching 3 courses this semester, and 2 of the classes are ones I have not taught previously.  I am teaching anatomical kinesiology for the 9th time during my 4 years at Mississippi State, and it is easily one of my favorite classes.  It is basically an overview of musculoskeletal anatomy starting with the foot and working up the body to the head and then down to the shoulder, elbow, and wrist.  My goal for the students by the end of the semester is that when they see a person performing a movement, they can name the joints that are involved, and the muscles that the person is using to accomplish the goal of the movement.

A new class I am teaching this semester is neural control of human movement.  I have previously taught motor development and motor learning, so I have some experience teaching about the nervous system.  To me, the nervous system is the most important system in the body, especially when it comes to human movement.  The nervous system is probably the most complex system as well, which makes the course challenging but fun.  There are many neural processes that occur during voluntary movement that we are not even aware of the majority of the time, and even the smallest disruption can cause errors in movement.  I am planning on starting another series of blog post on neural control very shortly.

The third class I am teaching this semester is a freshman seminar based on the television show "House."  This is a one hour course designed for students that are new to Mississippi State.  I have been a big fan of the show House and all the different medical mysteries on the show.  We are going to examine some the cases on the show and see how realistic they are.  We will also discuss why the doctors choose specific diagnostic tests.  It should be a lot of fun and a learning experience for all of us.

On the research side, we are about to begin a study this Wednesday investigating the relationship between ankle laxity ("looseness in the ankle joint"), balance, and landing kinetics (forces).  The study will examine people that have never sustained an ankle sprain, people that sprain their ankles frequently, and people that have sprained their ankle before but do not have any long term problems.  We are trying to see if there are differences in these variables between these different groups.  Several undergraduate students are taking a prominent role in this study.

All in all, it should be an exciting semester.  I am going to do my best to post at least two blog posts a week, so be sure to check back regularly. 

Just what are the benefits of PED use for baseball players?

Yesterday, major league baseball announced that San Francisco Giants outfielder Melky Cabrera tested positive for excessive testosterone, earning him a 50 game suspension.  Now, the debate has begun again, just like it does anytime an athlete tests positive for PED use, as to just how much of an advantage he or she gained by taking the banned substance.  The problem is, there is no clear answer to this question.

The reason this question cannot be definitively answered is that there is no way to isolate the effects of certain PEDs in a controlled laboratory setting (also, it would be nearly impossible to receive approval to conduct a study where these types of drugs were given to human participants).  There are numerous factors that effect the performance of a baseball player, including, but not limited to, hand-eye coordination, amount of practice/experience, motivation to perform, psychological status, muscular strength, muscular flexibility, etc.  While it is true that Cabrera's batting average has increased 91 points in two years, the effect that the excessive testosterone had on this increase cannot be determined.  Every other factor that could cause improvement in batting average cannot be controlled in order to isolate the effects of the testosterone. 

Now, I am not advocating the use of performance enhancing drugs.  They definitely can help cause increase in muscular strength, and they definitely have some very bad side effects, and they should not be allowed in athletics, as using them is a form of cheating.  However, scientists and researchers cannot quantify specifically how much of an advantage these drugs give an athlete.  Also, the punishment for a first time offense in both MLB and the NFL is not severe enough to discourage athletes from experimenting with PEDs.

Running with a fractured fibula

Although the Olympics are over, there is still time to examine some of the things that occurred over the past two and a half weeks.  One of the most impressive was US sprinter Manteo Mitchell finishing has leg of the men's 4 x 400 meter relay despite the fact that he was running on a fractured fibula.  How was he able to do this?  There are many factors that come into play, including his psychological condition and motivation, pain tolerance, and the fact that he is a world class elite athlete.  The only factors that I am able to analyze are the anatomical and biomechanical factors.

The fibula is the smaller, thinner bone located on the lateral (outer) side of your lower leg.  At the proximal (top) end, it articulates with the tibia (knee), and at the distal (bottom) end, it articulates with the tibia and helps form the ankle.  The "bump" on the lateral side of your ankle is the lateral malleolus, which is part of the fibula.  Due to the placement and size of the fibula, it does not play as large of a role in force absorption and weight bearing as the larger tibia does.  In fact, about 10-15 % of the force from the ground during walking and running is absorbed by the fibula, and the other 85-90% is absorbed by the tibia.  Even though it does not absorb as much force as the tibia, it is still a critical bone to transfer force from the foot and ankle up to the knee, and without a fibula, it would be nearly impossible to walk or run.  If Mitchell had fractured his tibia, he likely would not have been able to finish the race.  Since he fractured his fibula, he was able to finish, which was a very impressive accomplishment, not only because of the intense pain he was in, but also because the fractured fibula disrupted the normal transfer of force between the ground, and his foot, and ankle, and lower leg.  This is just speculation, but there is probably not a high percentage of people that would be able to continue running with a fractured fibula.

Biomechanics and the Olympics:Part X

Since the Olympics are ending on Sunday, this will be the last post of the series.  Again, with track and field being the focus of the Olympics this past week, some of these athletes are putting up really fast times.  Newton's third law is a critical factor in a person's capability to run fast.  Newton's third law is the law of action/reaction: "for every action there is an equal and opposite reaction."

In order for a person to walk or run, they exert a force from their foot into the ground.  The ground will push back with the same amount of force, but in the opposite direction.  This force from the ground is known as the "ground reaction force" and can be measured in a laboratory setting using an instrument called a force platform.  This force is measured in three directions: 1) vertical (straight up and down), 2) anterior-posterior (forward and back), and 3) medial-lateral (side to side). 

The way a person moves is influenced by the magnitude of the force applied as well as the direction the force is applied in.  If you want to jump as high as possible, you push straight down into the ground, and the ground pushes you straight up.  Almost all of the ground reaction force is in the vertical direction.  If you want to jump for maximum horizontal distance, you will apply a force both down and back into the ground, and the reaction force will push you up and out (consider a long jumper, they are trying to jump as far as possible, which has both a horizontal and vertical component).  When a person is running, they have a greater posterior ground reaction force when the foot hits the ground, and a greater anterior reaction force when they push off, which will propel them forward.  If a sprinter wants to increase his or her running velocity, he or she will need a greater anterior ground reaction force than posterior ground reaction force.  These sprinters are able to apply a large amount of force into the ground, at the optimal angle, in order to maximize the ground reaction force and run at very fast velocities. 

Biomechanics and the Olympics: Part IX

Another scary moment at the Olympics the other day occurred when pole vaulter Lazaro Borges had his pole snap during an attempt.  As you can see in the picture above, he was very fortunate not to be injured by this unfortunate accident.  Pole vaulting can be a potentially dangerous sport, as often times the athletes are attempting to use a pole to project themselves over a 15-17 foot high bar.  Why did Borges' pole break during this attempt?

When a structure is loaded, it will deform to a certain extent before it starts to break, and if the a load is still applied to the structure, it will eventually fail and rupture.  Think about holding a tree limb and applying a force to it.  Eventually, the limb will start to break, and if you continue loading it, it will rupture completely and become two separate parts.  We could plot a stress-strain curve for different materials (metal, glass, bone, muscle, tendon, etc.) to examine how they will behave when they are loaded.  Stress is similar to the load applied to the material, and strain is the amount of deformation.  The stress-strain curve is comprised of three main parts: 1) the elastic region 2) the plastic region 3) and the ultimate failure point.  If a material is loaded within the elastic region, it will undergo deformation, but it will return to its original shape once the load is removed.  If it is loaded past the elastic region into the plastic region, the material will start to show some small tears (microtrauma), and will not return completely to it's original shape after the load is removed.  If a material is loaded to or past the ultimate failure point, it will completely rupture and tear (break into two or more pieces). 

Now, the pole used in pole vaulting is highly elastic, which is beneficial because it will deform extensively and store potential energy which will be used later to project the vaulter over the bar.  Most of the time in pole vaulting, the pole is not loaded past its elastic limit, and no permanent deformation occurs to the bar.  Think about using a rubber band, if you pull the band back (but not too far), and then let it go, it releases a lot of energy and returns to its original shape.  If you pull the band back past its elastic limit, then it starts to show some little tears, and if you keep pulling the rubber band back, which increases the stress on the band, it will eventually break.  This is what happened to Borges' pole.  It was loaded past the elastic and plastic limits, to the ultimate failure point, and it broke.  Why did it happen on this attempt?  There are a few possible explanations.  Perhaps his pole had been loaded previously past its elastic limit to its plastic limit, and had already sustained some small deformation, and was weaker for this attempt.  It might have been due to pole placement and how the load was applied to the pole (unfortunately the video has been removed from the internet).  The fortunate thing is the he was not seriously injured.  In many of the Olympic sports,  the athletes are moving at very high velocities, producing a large amount of force, and sometimes have implements that they use or obstacles that are in their way.

Biomechanics and the Olympics: Part VIII

In my opinion, one of the most difficult events in track and field is the hurdles.  To get an idea, try running as fast as you can and jumping over an imaginary object every 10 meters.  It's not easy to do, and even more difficult when you add in a 42 inch (106.7 cm) high hurdle for men and a 33 inch (83.8 cm) high hurdle for women.  It is a skill that requires speed, strength and flexibility.  What joint actions are required in order to clear a hurdle?

If you watch hurdling, some athletes lead with their right leg, and some lead with their left leg, but it is always the same leg that leads.  In the picture above, the athlete in the middle uses her right leg to push off, and her left leg to land on.  We can call the right leg the propulsive leg, and the left leg the landing leg.  The propulsive leg has to produce enough force to project the runner and their legs up and over the hurdle.  This propulsive foot is not in contact with the ground for a very long time, but, the muscles in the right leg must apply a great enough force to the ground to get the runner over the hurdle.  The amount of force applied multiplied by the time interval over which the force is applied is known as impulse.  The primary muscles used during this propulsive phase are the hip extensors (gluteus maximus and hamstrings), the quadriceps, and the gastrocnemius and soleus (calf) muscles.

Once the athlete is in the air, they must now clear the hurdle.  If you look at the athlete's left leg in the picture above, the hip is flexed (moved in front of the torso) while the knee if fully extended (nearly straight).  This places a large amount of tension on the hamstrings; if the athlete does not have good flexibility in this muscle group, they will have difficulty clearing the hurdle and will have a greater risk of injury.  Once the lead leg clears the hurdle, the trail leg also has to clear.  The knee of this leg is in a flexed (bent) position, while the hip is going first extend (go back behind the torso), then abduct (move out to the side), and then flex to clear the hurdle. 

After clearing the hurdle, the athlete is now going to land on the lead or landing leg.  Impulse becomes important again, because the foot/ankle/lower leg has to absorb the impact forces from the ground, which will be applied over a very short time period, and then apply a force to the ground to propel the body forward to continue running.  This running and jumping cycle will be repeated several times (depending on the length of the race) over the course of the event, and one poor jump where the athlete hits the hurdle can take them from 1st place to last place (see the picture below from the men's race).  In order to be successful at this event, the athletes must be able to run at a very high velocity, be able to produce enough force to jump over the hurdle, must have enough flexibility to clear the legs over the hurdle, and must be able to absorb the impact forces when they land.  This is a very demanding event that requires a very specific skill set.