Tag: tendon/ligament

Oops I Did It Again: The Biomechanics Behind Repetitive Ankle Injuries

Ankle injuries – either sprains or fractures – are one of the most common sports traumas plaguing the US today. Sprains are overextensions or tears in ligaments.  Fractures, on the other hand, are broken bones.

Here, we will focus on sprains of which there are three grades. To help visualise a sprain, think of a Fruit By the Foot (the gummy fruit snack you may have eaten as a child). A Grade 1 sprain involves stretching like if you were to pull on either end of the fruit rope and small tears start to develop along the middle. A Grade 2 sprain develops when the tear is larger and originates from a side; a grade 3 sprain is a complete tear into two pieces.

A Little Background

The ankle joint, also known as the talocrural joint is a synovial hinge joint that mainly moves in dorsiflexion and plantarflexion 1. If you were sitting on the ground with both legs extended in front of you, dorsiflexion is the movement of your foot upwards toward your shin, and plantarflexion is the action associated with pointing your toes moving away from your body.

Video Explanation of Ankle Movements in Dorsiflexion and Plantarflexion

Sprains & Pains

The most common type of ligament injury are lateral ankle sprains or inversion sprains where the ankle joint over rotates in the outward direction, especially an inversion while in plantarflexion 2. Exercises that include running, jumping, and/or cutting put the athlete’s ankle at high risk for sprains. This is especially seen in soccer, football, basketball and volleyball players.

Depiction of ankle position with an inversion sprain. Light purple items are bones and have rectangular callouts, while red items are ligaments with circular call outs. Labeled items include: Tibia, Fibula, Talus, Cuboid, and Calcaneus bones as well as the ATFL, PTFL, and CFL (ligaments).
Figure 1 – Left Foot/Ankle in an over-rotation with main bones (in square callouts) and ligaments (in circle callouts) identified

Figure 1 above shows an ankle in the common and compromising position of an inversion sprain. The circled ATFL, PTFL, and CFL are ligaments in the joint, namely the Anterior Talo-Fibular ligament, the Posterior Talo-fibular ligament, and the Calcaneofibular ligament respectively. Additionally, the boxed call outs are bones in the foot.

Numbers show that close to 70% of patients that had experienced a lateral ankle sprain in the past repeated the same injury to their ankle1.

What is the medical explanation behind repeated ankle injuries?

One study by Doherty et al. followed emergency room visits for ankle injuries and found that 40% of patients with ankle sprains had to seek medical treatment for another ankle injury within the year. Yet, another statistic found that over half of people who experience ankle sprains don’t even go to a hospital.

Ankle sprains are sometimes deemed as a “walk-off injury“, or one that hurts momentarily but just needs a few minutes before resuming activity. However, many people suffer from prevalent and reoccurring ankle sprains. Officially dubbed Chronic Ankle Instability or Sprained Ankle Syndrome, this condition is characterised by a host of symptoms including pain, swelling, perceived and actual instability, balance issues, and joint weakness. Chronic Ankle Instability, or CAI more commonly, can also cause a decrease in physical activity, changes to walking or running form, onset arthritis, and problems with knees and hips due to overcompensation1.

The tried-and-true course of action to prevent CAI is efficient rehabilitation. A study showed that if the patient recovers fast enough, the body won’t change movement patterns.

Problem: Altered Movement Patterns

The changing of movement patterns in the ankle joint, or arthrokinematics1 is one of the main factors that contributes to CAI. The brain, like a protective mama bear, trains the body to operate (walk, run, jump) in a different manner to protect the strained ligaments. Over time, muscle memory kicks in and the compensation for ankle mobility becomes your new normal. This adoption of an incorrect form of walking, running, jumping, etc. can backfire and translate to repeated ankle injuries. This muscle memory has been identified as a neurosignature2 from Melzack’s neuromatrix of pain theory; however, this pain theory also describes how elimination of the pain, stress, or chronic symptoms associated with an ankle sprain can prevent reoccurrence – elimination, that is, through efficient rehab.

Solution: Efficient Rehabilitation

A quick recovery can be achieved through various muscle strengthening exercises from a licensed physical therapist or “ankle disk training,” which basically consists of a flat board mounted on a semi-circle. By standing on this unbalanced board, stability can be practiced as well as specific ligament targeting to build muscle. A more serious solution of ankle surgery showed a 90% success rate of mediating mechanical instability, but this is not a widely-practiced nor traditional treatment plan for CAI3. In fact, ankle taping and/or lace-up 3 bracing when exercising proved most helpful in preventing over rotations of the lateral ligaments.

Ankle Sprains: An Epidemic in the World of Athletics

Have you ever been out running on a gorgeous fall day, only to have the run cut short by a painful misstep on a tree root covered by leaves? I have, and let me tell you – it’s awful! And even if you aren’t a runner, according to the Sports Medicine Research Manual, ankle sprains are a common, if not the most common, injury for sports involving lower body movements. Now, the solution to preventing this painful and annoying injury could be as simple as avoiding tree roots and uneven ground, but the real problem behind ankle sprains deals with the anatomy of the ankle.

The ankle is made up of many ligaments, bones, and muscles. However, when sprained, it is the ligaments that are mainly affected. Connecting bone to bone, ligaments are used to support and stabilize joints to prevent overextensions and other injuries. The weaker a ligament is, the easier it is to injure. There are three main lateral (outer) ligaments supporting the ankle joint that can become problematic: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. According to a study from Physiopedia, these lateral ligaments are weaker than those on the interior (medial) of the ankle, with the anterior talofibular ligament being the weakest.

An image depicting the various ligaments of the ankle, both lateral and medial.
Anatomy of the ankle, highlighting the lateral and medial ligaments

The next question that has to be asked is why are these ligaments so much weaker than other ones? The answer to this question is based on their physical make up. Ligaments are made of soft tissue that has various collagen fibers running parallel to each other throughout it. The more fibers there are, the more structure and rigidity there is. Think of the fibers as a rope: The rope can stretch to a certain point, but once it hits that point it will snap and break. But if you have a thicker rope (such as the medial ligaments), it becomes much harder to break.

The ligaments on the outer part of the ankle have fewer collagen fibers than those on the inside of the ankle. Thus, when the ankle is moved in an awkward position, it is more likely that the lateral ligaments will break.

Once you sprain your ankle, the focus turns to treatment. Treatment will differ slightly for every individual depending on the severity of the ankle sprain. The simplest way to treat a sprained ankle is to follow the RICE (Rest, Ice, Compression, Elevation) method. Other forms of treatment include taping the ankle or using a brace to restrict movement and to add support and extra stability. Wearing proper footwear is another way that one can prevent and help treat a sprained ankle, as certain shoes are specifically designed to help avoid such injuries. To prevent future ankle sprains, exercises are recommended to help strengthen and stabilize the joint and surrounding ligaments and muscles.

For more information on ankle anatomy and sprains, check out these articles on BOFAS and SPORTS-Health.

Tearing and repairing the meniscus

How does someone go from being the youngest NBA MVP one year to barely making headlines the next? Ask Derrick Rose. After being named the youngest MVP in the NBA, Derrick Rose tears his ACL the next year and then tears his right meniscus twice in the span of three years. Knee injuries have not been kind to Derick Rose, but how does one tear their meniscus and how does it get repaired?

The meniscus is shown in Figure 1.

Showcases the location of the meniscus in the knee. Gives the user an image of how the meniscus works, and where it is located.
Figure 1

According to Sports Health, the meniscus is a type of cartilage that provides cushioning between the bones in the knee. The meniscus main role is to absorb shock and the impact on the leg and knee when it is in motion. It allows for stability and smooth motion between the joints.

In a game of basketball, one of the biggest sports in the United States, there is plenty of running, jumping to shoot the ball into the basket, jumping up to catch a rebound, and doing sharp cuts during the game to shake off a defender. All these movements cause high loading on the knee, and if there is an over-rotation on the knee during these movements, then it can cause a tear in the meniscus. The video below shows when Derrick Rose tore his meniscus.

In the video, it shows Derrick Rose doing a relatively easy movement, he plants his foot in order to change direction to chase after the ball. It is a non-contact movement, but due to an awkward landing on his foot, he gets injured and misses games for the rest of the season.

When the meniscus is torn, there are two options in terms of healing the tear. The options are getting the meniscus removed or getting it repaired. Both options have their own recovery time. If you get the meniscus removed, then the recovery time would be from four to six weeks. However, there are setbacks to getting the meniscus removed such as leading to early arthritis. If the meniscus is repaired, then the timetable to return to play is around six months. According to USA Today , he chose to get the meniscus repaired in order to not have future complications around his knee, which is why he had to sit out for the rest of the season. Going this route also gave Derrick Rose the chance to return to his playing form before injury. According to Stein, 96.2% of athletes that undergo meniscal repair go to pre-injury level of activity after the repair, which is good news for Derick Rose.

However, Derrick Rose tore his meniscus again the following season in 2015. He would then have surgery to remove the damaged part of the meniscus and would return in a couple of weeks. This would then be his third surgery to repair his knee, and his surgeries must have an effect on his playing performance. After these surgeries, the world waits to see if Derrick Rose can reach MVP status again during his career. It would be tragic to see that these knee injuries would ruin someone’s career.

Sources and Additional readings:

General information about the meniscus

Meniscal Injuries in the NBA

Injuries in the WNBA

What is Tommy John surgery?

Baseball card of Tommy John for the Los Angeles Dodgers
From Zellner, “A History and Overview of Tommy John Surgery,” Orthopedic & Sports Medicine Specialists

In July of 1974, Tommy John, pitcher for the Los Angeles Dodgers, felt a twinge in his throwing arm, and could no longer pitch. Dr. Frank Jobe tried a new kind of surgery on John’s elbow, and after missing only one season, Tommy John returned to the mound in 1976 and continued pitching until 1989.

How?

The surgery which bears Tommy John’s name is by now a common buzzword in the baseball community. Over 500 professional and hundreds of lower level players have received this treatment, but even the most avid fan may still be unsure what it means.

Tommy John surgery is the colloquial name for surgery on the Ulnar Collateral Ligament (UCL). This ligament is vital to the elbow, especially in the throwing motion. Injury to the UCL accrues over time; fraying and eventual tearing occurs after repeated and vigorous use. Baseball pitchers, throwing around 100 times per game and at speeds upwards of 100 mph, put themselves in danger of UCL injury.

Location of the Ulnar Collateral Ligament in the human arm, shown on a baseball pitcher.
Image from Wikimedia Commons.

Tendons in the elbow joint, with the Ulnar Collateral Ligament marked
Image from Wikimedia Commons

What can be done when a player injures his or her UCL?

Prior to 1974, not much. Ice and rest, the most common suggestions, would do little to improve serious UCL damage. A “dead arm” spelled the end of a player’s career. Dr. Jobe would change that. 

Jobe removed part of a tendon from Tommy John’s non-pitching forearm and grafted it into place in the elbow. John’s recovery required daily physical therapy before slowly starting to throw again.

Since Jobe’s pioneer surgery on Tommy John, most patients undergo a similar kind of reconstruction procedure. A tendon from either the forearm (palmaris longus) or the hamstring (gracilis), is looped through holes drilled in the humerus and ulna, the bones of the upper arm and inner side of the forearm. In some modern cases, the hope is to repair the UCL with a brace that lets it heal itself rather than total replacement. This allows for faster recovery time because the new blood vessels that have to form in traditional ligament replacement are unnecessary. In either case, athletes recovering from UCL surgery, a procedure which itself takes less than two hours, typically require at least a year to restore elbow stability, function, and strength.

Some misconceptions about Tommy John surgery exist. One 2015 study found that nearly 20% of those surveyed believe the surgery increases pitch speed. However, increase in pitch speed may be affected more by the extensive rehabilitation process rather than the new tendon itself.

The study also found that more than a third of coaches and more than a quarter of high school and collegiate athletes believe the surgery to be valuable for a player without an injured elbow. This perception of Tommy John surgery makes it seem like a superhuman kind of enhancement, as if out of The Rookie of the Year, or worse, it becomes like a performance enhancing drug. In reality, a replacement UCL at best replicates normal elbow behavior. A procedure capable of creating a superhero might be attractive, but for now, Tommy John surgery just helps players get back in the game.

 

For further information:

 

How Many MLB Players Have Had Tommy John Surgery?

What Makes Someone More Likely to Tear Their UCL?

It takes a lot to make a professional athlete collapse to the ground during a game. After throwing a pitch on September 14, 2019, Toronto Blue Jays pitcher Tim Mayza knelt on the side of the mound while clutching his arm, expecting the worst. The next day, MRI revealed that what he had feared: Mayza had torn his Ulnar Collateral Ligament (UCL).

player following through after throwing baseball
Photo by Keith Johnston on Unsplash

Because of UCL reconstruction, or Tommy John, surgery, this injury is no longer the career death-sentence that it once was, but there is still a long road ahead for Mayza. He probably will not pitch in a game again until 2021. Sadly, this injury is only becoming more and more common among MLB pitchers. In the 1990s, there were 33 reported cases of UCL tears by MLB pitchers. In the 2000s, this number more than tripled to 101. From 2010 to the beginning of the 2015 MLB season, 113 UCL reconstruction surgeries had already been conducted. It has become so common that surgeons have called it an epidemic, and researchers in the US and abroad are attempting to find a way to combat this increase.

Digital image of elbow joint, with a small, red tear in the UCL
Orthopaedic and Neurosurgery Specialists, 2019

The UCL connects the ulna and humerus at the elbow joint, and its purpose is to stabilize the arm. During the overhead pitching motion, the body rotates in order to accelerate the arm and ball quickly, putting a large amount of stress on the UCL. In fact, according to a study by the American Sports Medicine Institute, the torque, or twisting force, experienced by the UCL during pitching is very close to the maximum load that the UCL can sustain.

Recently, many studies have investigated factors that could make pitchers more susceptible to UCL injuries, with a hope of identifying ways to prevent them. One of the biggest findings has been the correlation between UCL tears and pitch velocity. According to a study from the Rush University Medical Center, there is a steady increase in the frequency of UCL tears as max velocity increases. This makes intuitive sense, as more torque would be required to accelerate a baseball to the higher velocities. While this finding does have a very strong correlation, it does not help the players avoid injuries. Pitchers are unlikely reduce their velocity because it would also decrease their effectiveness, so another answer must be found.

The University of Michigan conducted another study, and found that, in addition to velocity, the number of rest days between appearances decreased by just under a full day for pitchers who later needed Tommy John surgery. While this does not seem like a large number, starting pitchers typically only receive 4 days of rest between starts, so the extra .8 days is equivalent to a 20% increase in rest time.

Because of these findings, the MLB has increased the max roster size from 25 to 26 for the 2020 season, with the hope that teams will use the extra player to reduce the frequency that each pitcher is used. In addition, pitch counts in Little League Baseball have had a positive effect on youth injuries. This can be explored further here. This discovery has already made a tangible impact on Major League Baseball, and hopefully more findings will reduce the rate of UCL tears in the future.

Brace yourself… You might need surgery

A surgery? For my PCL? Could be more likely than you think.

Usually hiding behind it’s annoying and commonly ruptured brother the ACL, the PCL (posterior cruciate ligament) is a durable ligament that usually doesn’t cause problems for athletes… until it does.

Because of the strong nature of the ligament, injuries that tear the PCL are usually sudden and traumatic. Think car accidents, falling hard on a bent knee… you get the picture. When enough force is applied to the top of the tibia, the tibia can be pushed backwards, past the threshold of the PCL. Even though the PCL does its best to hold your femur and tibia together in the right spot, it just doesn’t hold up to the brute force of a dashboard. These injuries can usually be diagnosed by the presence of a “sag.” When your doctor holds your bent knee up, it looks like your shin bone is sagging underneath your knee. This is your torn PCL crying for aid.

A photo showing the location of the PCL and ACL inside of the right knee. The ACL crosses from left to right over the PCL. Both are attached at the top to the femur and at the bottom to the tibia.

When it comes to fixing these injuries, the nonsurgical approach has typically been recommended for low-grade tears that don’t totally rip the PCL apart. These braces are attached to the leg right above the knee, and are supposed to hold the bottom part of your leg under the knee in place. This prevents from your knee from going too far forwards and backwards, and allows scar tissue to build up over your PCL. While your body tries to heal itself with scar tissue, you will work with a physical therapist to build up your quad strength and restore your range of motion. Over 80% of athletes are able to return to play after bracing their knees.

A PCL brace is shown in place on a knee. There are two stabilizing straps above the knee, and two below the knee. They are connected by a metal frame that meets at a hinge joint over the side of the knee.

However, surgery, which was once only reserved for extreme PCL tears, is now seen as a viable, cost-efficient option for even low-grade tears. PCL surgery is intended to restore normal knee biomechanics and stability to about 90% of their post-injury strength. Sometimes, a part of the Achilles tendon is used to create a graft, or a “new” PCL. This is called an allograft, and results in safer and shorter surgeries (8). Within a month, the athlete can walk and bear their own weight. After six months, athletes are able to return to sports.

In theory, surgery sounds like the most “permanently good” option there is for fixing your PCL. However, no scientific studies have yet been done that can accurately compare the return-to-play rates, or even the relative healing of people in braces versus people who immediately got surgery. When people don’t comply with their treatment plans (aka, take off their braces early, skip physical therapy after surgery, etc.) the data for comparisons between bracing and getting surgery aren’t clear. While your PCL may be out of commission, so is the jury on this one. At the end of the day, the best treatment method for you is dependent on the mechanism of injury, severity of your injury, and whether you plan on listening to your doctor or not!

For more info on PCLs:

Posterior Cruciate Ligament Injury

Management of PCL tears

ACL Reconstruction: Which Option Is Best For You?

200,000 ACL injuries occur each year, and ACL reconstruction is the 6th most performed surgery in the United States, so to come back bigger, faster, and stronger, the right recovery path is critical.

The anterior cruciate ligament (ACL) is a critical part of the knee joint that connects the femur (‘thighbone’) to the tibia (‘shinbone’). Its main functions are to support the knee joint during side-to-side motion, such as cutting, shuffling, or pivoting, and to prevent the tibia from moving too far forward relative to the femur. When an ACL ruptures, it is very common to reconstruct it to bring someone back to performance level.

Location of the ACL inside the knee joint with other labeled bones and ligaments with another diagram showing a ruptured ACL.
Image from Wikimedia Commons “Anterior Cruciate Ligament”

The basis of ACL reconstruction is using living tissue, also known as grafts, to replace, and function as a substitute, for the torn ACL. There are four types of ACL reconstruction surgeries that use different types of grafts. Those four types of surgeries are classified as autograft reconstruction, allograft reconstruction, xenograft reconstruction, and synthetic reconstruction. Autograft surgeries require one’s own grafts to repair the ACL, allografts require a cadaver’s grafts to repair the ACL, xenografts require an animal’s grafts, and synthetics require manufactured materials. Additional articles on xenograft reconstruction and synthetic reconstruction can be accessed here and here.

Each surgery requires the removal of the damaged ACL, and then the incorporation of a new substitute by tunneling the newly selected graft through the femur and tibia. Within the autograft group, the two popular grafts for reconstruction are patellar tendon and hamstring tendon, with quadricep tendon being another, less popular, choice. The patellar tendon surgery takes the middle third of the patellar tendon, a tendon that connects the kneecap to the tibia, and makes sure to include the bony ends.

The hamstring tendon surgery takes two small slivers of each of the two hamstring tendons, connecting the hamstring muscle to the tibia, coils them up, and then finally bundling them to increase strength.

A knee joint with bones, ligaments, and tendons labeled.
Image from Wikipedia “Knee Joint”

For the allograft surgeries, a surgeon may select an Achilles, patellar, hamstring, or quadricep tendon from the donor.

It is very important to choose the right surgery. While the determination of which surgery and technique to perform falls heavily on the surgeon’s and patient’s preference, there are advantages and disadvantages of each technique which tend to persuade the choice of surgery. The main concepts surrounding the decision of which surgery to perform are the activeness of the patient, muscle strength, and previous knee injuries. Depending on the job, sport, or activity of the patient and the desired return time, one technique may be a better fit.

For a patient participating in low demand activities, allograft surgery may be the best fit due to less post-surgery pain and quicker surgery time, however it is very expensive and offers less tensile strength compared to autografts. As for autograft surgeries, patellar tendon reconstruction allows faster recovery time due to the bone-to-bone bonding and offers a strong substitute for a torn ACL, however future knee pain is very common. Hamstring tendon reconstruction requires more recovery time; however, the post-surgery pain is significantly less than the patellar tendon reconstruction and the tensile strength of the hamstring tendon is the strongest possible substitute.

Additional reading and comparisons between the popular autografts and allograft techniques can be accessed here and here.

Do you have an ACL?

Whenever there is a lower extremity injury in sports, the first thing people always ask is: “Was it the ACL?” I, like everyone else, assumed everyone had an ACL because I did not believe that you could walk without one, let alone play sports. To my surprise, I discovered that not everyone has an ACL. Some people are born without one, while others lose their ACL’s. Hines Ward, an NFL All-pro wide receiver, went his whole football career without an ACL. Ward lost his ACL during an accident when he was about 4 years old and the doctors were unaware. He did not find out that he did not have an ACL until he was making the transition from college to the NFL.

 

Being born without an ACL it is referred to as the congenital absence of the anterior cruciate ligament and is an extremely rare condition. Only about 2 in every 100,000 live births are subject to this congenital absence of the ACL. It is caused by an insufficient development of the knee joint when a baby is in the womb. Others do not have ACL joints due to a complete rupture of the ligament. There was a case of a 25 year old woman who had instability in her left knee joint and had no history of knee trauma. Physical investigations showed no swelling or tenderness, but after an MRI it was discovered that she had no ACL joint and the PCL was hypoplastic.

 

The knee is essentially a hinged joint that is held together by the medial collateral (MCL), lateral collateral (LCL), anterior cruciate (ACL) and posterior cruciate (PCL) ligaments.

labelled structure of the knee. Shows the quadricep muscles, quadricep tendons, patella, femur, tibia, fibula, Patellar tendon, meniscus, MCL, PCL, LCL, and ACL

Perry, Pig Knees And Rising Youth ACL Tears, 2018The ACL is a major ligament in the knee that connects the femur (thigh bone) to the tibia (shinbone). The ACL is similar to an actin filament. It has a rope-like structure and is best loaded under tensile loading. The ACL prevents forward movement of the tibia on the femur, as well as hyperextension, which is the straightening movement of the knee that goes beyond the normal range of motion in the joint. By preventing these motions, the ACL provides stability to the knee joint and allows for dynamic motions. Without this stability in the knee joint, humans would not be able to walk normally, let alone perform complex movements done in sports.

picture of actin filament with the plus and mins ends labelled
Mechanobiology Institute, What are actin filaments?, 2018.

 

People with knee joints that lack ACL’s tend to develop a knee joint where the femur bone fits into the tibia a bit like a shallow ball and socket joint. A knee joint without an ACL uses the meniscus to perform the same function. The meniscus is a tough rubbery cartilage that normally acts as a shock absorber between the tibia and fibula. In order for their meniscus to serve the same function as the ACL, the meniscus undergoes deformation to make it better suited for tensile loading. More information about ACL’s can be found here.

What’s more important for athletes: training or genetics?

Usain Bolt, Michael Jordan, and Wayne Gretzky are arguably some of the greatest athletes of all time. You watch them on the television breaking record, winning titles or making impossible shots, and you can’t help to wonder, how are they that good? Do they use some secret training method, maybe even a special diet? Possibly, they are genetically gifted? Sports author David Epstein tackles this debate of training versus genetics in his book, “The Sports Gene”. Yes, athletes need to practice to become good, but some are just going to be naturally better than others. If you are 5’6” inches you are going to have to practice dunking a basketball a lot longer than someone who 6’6”. To see how some athletes are naturally better than others lets look at some talented athletes and see what makes them biomechanical specimens. First, we’ll look at Michael Phelps, an American swimmer who not only has multiple world records but also the most decorated Olympian of all time with 28 Olympic medals.

 

For swimmers, biomechanics have found the ideal body for performance. Body features that have been found helpful for swimming is a long torso and long arms.  The long torso reduces the drag on the swimmer and long arms allow for more powerful strokes. Michael Phelps’, who is 6’4”, has the torso proportions of someone who is 6’8” and the leg proportions of someone who is 5’9”, giving him an extremely high torso-to-leg ratio. Not only is Phelps’ torso long, but he also has a long wingspan, measured at 6’7”. Along with Phelps’ unreal proportions, his feet are another huge advantage when it comes to swimming. His size 14 feet help place more force into the water when he kicks. This is a benefit because 90% of a swimmer’s thrust comes from their feet. His ankles also hyperextend 15-degree when he kicks, creating more force. Biomechanically, Michael Phelps’s is a walking fish.

Modified from Hart Blenkinsop, Michael Phelps: The man who was built to be a swimmer 2014

You might be wondering, what would happen if you took someone who has trained to mastery and put them up against someone who is just perfectly gifted. David Epstein mentions this scenario in his book a battle between training and genetics. In the 2007 world high jump final, there are two jumpers left, Stefan Holm and Donald Thomas. Stefan Holm, has a personal best of 7’10.5”, only 2 inches off the world record. Holm has been training most of his life, since he was a child and even won the previous Olympic High Jump final. He is also 5’10” tall, which is very small for a high jumper. Donald Thomas, has a personal best of 7’8.5”. Thomas, on the other hand, is 6’3” and has been jumping for a little over a year and had started high jumping because of a bet with a friend. The two finish the completion and Thomas won clearing a 7’8.5” bar. Even though Holm’s technique was near perfect, Thomas just had the athletic edge. Being taller, Thomas already had a higher center of gravity meaning he had to travel less distance to get over the bar. Thomas also had much longer legs and Achilles tendon. This allows him to store and transfer much more energy into a jump. Thomas was just made to win.

 

For more information:

Michael Phelps: The man who was built to be a swimmer

Nature or Nurture?

Exciting Advance in ACL Repair

Anterior Cruciate Ligament (ACL) injuries are among the most common in sports, with nearly 100,000 tears annually. Additionally, the rate of pediatric tears has been increasing at a rate of 2.3% each year for the past 20 years. The high incidence of this injury is in part due to the structure of the knee complex, where the ACL is located. The ACL helps connect the two longest bones in the body and is responsible for rotation and transferring body weight to the ankle. Specifically, the primary functions of the ACL are to prevent the tibia from sliding too far in front of the femur and to provide rotational stability to the joint. This rotational motion, combined with a lack of muscle support at the knee, is why so many athletes tear their ACL. A recent paper looked into how a team of doctors led by Dr. Martha Murray at Boston Children’s Hospital have come up with a promising new approach to repairing the injured ligament.

Two side views of the knee joint, one showing a healthy knee and one showing a complete ACL tear.
Photo by BruceBlaus on wikimedia.org

Due to its environment, ACLs do not repair on their own like other ligaments do. The synovial fluid, which resides in the knee complex to reduce friction in the joint, limits blood flow to the ACL and PCL (posterior cruciate ligament). When injuries occur to these ligaments, the lack of blood flow prevents clotting. In most other ligaments, clotting would occur and would function as a “bridge” for the two ends of the torn ligament to grow and heal across. Due to ACLs not being able to undergo this process, the current method for repair is to take a graft from the patient’s hamstring or patella and replace the torn ACL with the new graft. While this method is typically successful, Dr. Murray’s team estimates that the re-tear rate is about 20% and up to 80% of patients develop arthritis in their knee 15-20 years after the surgery. To combat this, Dr. Murray drew inspiration from how other ligaments heal and developed Bridge Enhanced ACL Repair (BEAR). The premise of this technology is to take a “sponge” that is composed of proteins that are naturally found in the ACL, and insert it between the torn ends of the ACL.  Using sutures, the sponge is moved into position and the two ends of the ACL are pulled into the sponge. Blood is then drawn from the patient and inserted into the sponge. This environment acts as a blood clot and stimulates the ACL to repair itself. Clinical trials have shown that the sponge resorbs completely after 8 weeks, at which point the two ends of the torn ACL have begun to join back together. While the BEAR treatment is still relatively new, early results are encouraging with patients seeing similar results to patients that undergo traditional ACL reconstruction. Though it is difficult to predict the rate at which patients who receive BEAR treatment will develop arthritis, animal testing has shown lower instances of osteoarthritis development, which is promising news for those who suffer from this common injury.

For more information about the BEAR technology check out Boston Children’s Hospital website or this recent article. A short video detailing the technology can also be seen below.