July 1, 2016

Researchers Aim to Promote Injury Prevention Among Adolescent Athletes


E.Lyle Cain, Jr., M.D.

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During the past decade, orthopedic surgeons have seen an increase in the number of injuries occurring in adolescent athletes and a decrease in the age at which adolescent athletes receive surgery for these injuries. Both of these changes indicate higher rates of injury at a younger age. Orthopedics Today spoke with several experts in this area about recent research and societal recommendations that may impact the training and treatment of young athletes.

Currently, one of the focal points of research in pediatric sports medicine is on injury prevention, according to Shital N. Parikh, MD, associate professor of orthopedic surgery at Cincinnati Children’s Hospital Medical Center.

“Early, single sport specialization has not been shown to improve future athletic performance, but has been shown to be detrimental both physically and emotionally for the young athlete,” said Parikh, who is also an Orthopedics Today Editorial Board member. “[It] is important to stress long-term consequences extending into adulthood exist for the athlete who specializes at a young age.”

According to Matthew V. Smith, MD, MSc, of Washington University in St. Louis, there has been a lot of work done to pinpoint why adolescent athletes get injured, including implementing guidelines in youth baseball and research on improvements in strength and movement patterns to prevent ACL injuries.

Two studies recently published by Peter N. Chalmers, MD, shoulder and elbow surgery fellow at Washington University in St. Louis, and his colleagues showed pitch velocity, pitcher height and pitching for more than one team correlated with a history of shoulder and elbow injury among adolescents. They also found higher pitch velocity was the most predictive factor of ulnar collateral ligament (UCL) reconstruction among Major League Baseball players. According to Chalmers, these results suggest future youth pitching injury prevention guidelines may need to consider pitch velocity in concert with pitch counts.

He added there is more understanding that a lack of core strength in youth pitchers may lead to injury. However, Chalmers said an increase in the application of technology, specifically among adolescent pitchers, may help adolescent athletes avoid injury while making sports more fun.

“We are already seeing commercially available [and] inexpensive accelerometers worn on the elbow that interact [with] iPhone software specifically developed and calibrated to measure pitching kinematics,” Chalmers said. “We are also seeing more widespread use of video analysis software and more inexpensive cameras able to take high-frame rate video for analysis. It is certainly possible markerless motion analysis technology will also become inexpensive and commercially [available] and will percolate into youth athletes, although that is still on the horizon.”

One way the American Orthopaedic Society for Sports Medicine has promoted injury prevention is through the Stop Sports Injuries Program, which provides information for athletes, parents and coaches on the best ways to prevent injuries within a specific sport. Similarly, the American Sports Medicine Institute provides information on risk factors for injury and how to minimize these, specifically among youth baseball players.

“We have gotten better at preventing certain injuries, such as baseball injuries with pitch counts [and] recommendations about time off per season, and some of the recovery time recommendations we have provided have been adopted by organizations, such as Little League Baseball and others,” E. Lyle Cain Jr., MD, of Andrews Sports Medicine and Orthopaedic Center in Birmingham, Ala., told Orthopedics Today.

Prevention of sports injuries

Overuse injuries, one of the most common injuries in adolescents among all sports, can occur when a young athlete specializes in one sport too early rather than playing multiple sports.

“[Athletes] at younger ages are becoming single-sport athletes, [even] single-position athletes, and I think that contributes to overuse,” Chalmers said. “There is an increasing amount of evidence to suggest [overuse injuries] may be a contributor to future injury.”

Sport specialization at an early age can cause adolescents to experience burnout symptoms, according to Parikh, including becoming over-dependent (due to increased control and regulation of their lives by adults) or socially isolated from their peers due to a lack of free time or home-schooling.

“Initially, the young athletes may enjoy their particular activity but, at some point, they would have burnout symptoms as the activity provokes more stress and performance anxiety,” Parikh said.

Smith said playing on multiple teams in the same sport during a season also can contribute to overuse injuries. He also advised youth athletes to learn off-season conditioning prior to returning to sport to avoid injury.

“We have seen a little bit of that happening in youth softball pitchers where their risks of injury are higher in the first 6 weeks. This may be related to a lack of preseason conditioning or followed by a rapid increase in sport-specific activities. We do not know yet for sure, but this is an area for future investigation,” Smith said.

Shoulder injuries are common from overuse in throwing, athletes. The pain may start with throwing but can eventually prevent adolescents from performing normal activities of daily living if left untreated, Smith noted. According to Cain, injuries to an adolescent’s growth plate can affect the way the bone ultimately forms and develops.

Lawrence Wells, MD, associate director of sports medicine at the Children’s Hospital of Philadelphia and associate professor of orthopedic surgery at the Perelman School of Medicine, said knee injuries can increase the risk for children to develop early-onset arthritis and can lead to pain and disability.

“Even more concerning is when athletes have injuries to the cartilage surfaces within the knee or shoulder and those changes can lead to arthritis and future problems in those joints that may not be recoverable,” Cain said.

Although not all injuries are preventable, by participating in multiple sports and not specializing in a single sport before 12 years of age, adolescents can lower their risks of preventable injuries, Parikh said. Cain noted taking time off from one particular sport to play another sport that utilizes different ligaments and joints can help reduce overuse injuries, such as a baseball player participating in soccer during the off-season.

“The main recommendation is whatever sport a child is playing, the child probably needs to play that sport 8 months or less each year and have some time off to rest and let each body part [recover] from whatever trauma or stress that area sees doing that sport,” Cain said.

Other ways injury can be prevented in adolescents include adequate supervision and training, wearing protective equipment and participating in annual pre-participation medical evaluation, which Parikh said can identify conditions that may predispose an athlete to problems during sports participation.

“There has been a lot of research in the last several years trying to determine what risk factors [are] important to cause some things to fail, like an ACL or a knee,” Cain told Orthopedics Today. “There have been several centers that have come out with prevention programs where there is a landing program from a jump, learning how to land properly [and] different strength test assessments, so doing preseason evaluations to determine who is at risk for injury are important.”

Research on adults

According to Chalmers, research on professional adult athletes may help guide injury treatments and injury prevention in adolescent athletes.

“Some of the ways in which we have seen a positive influence are, [as] we have come to understand professional pitching, our understanding of these optimal biomechanics has trickled down into teaching youth pitchers better biomechanics from a younger age,” he said.

Importantly, Parikh noted research on professional adult athletes can shed light on long-term consequences of injuries adolescents could be at risk for, such as the possibility of developing chronic traumatic encephalopathy from concussion.

“Research on the injuries that occur in pro athletes highlights risk factors for injury that helps the general population to understand it can also happen in their kids,” Smith said.

Conversely, Wells said research on adults may not adequately or safely apply to children, as they are skeletally immature. Cain also observed certain treatment methods that can help prevent injury among professional adult athletes may not be beneficial to adolescent athletes and can even be harmful to this population.

“[In] some cases, you can extrapolate the treatment options and the treatment algorithm the way we followed these along from the professional athletes, and you can use some of the same recovery phase goals and some of the same treatments from a physical therapy standpoint on the younger athletes,” Cain said. “It is important, though, to realize young athletes are not small adults. They are different because of the growth plates, [the] growing bones and the early structures of the body.”

Future research, management

As surgeons are beginning to recognize the differences between young athletes and adult athletes, Wells noted a heightened specialization in the management of and increased learning about young athletes. By beginning research at youth-level sports and following participants into adulthood, Smith said researchers may be able to identify the most appropriate management for athletes who are still physically maturing.

“These are all things that are hard to research and require a lot of patients that you follow prospectively and with a lot of measurements to see how things change over time. I think that is where research needs to go to pinpoint an athlete’s risk for injury,” Smith said.

He observed while pitch counts are an important way to provide a general estimate of how much adolescent athletes should be pitching, recommendations should be based on the conditioning and maturity of individual athletes. Chalmers said understanding fatigue in athletes and how it may lead them to become injured and ways to combat injury caused by fatigue are also important parts of future research.

“As [any athlete] gets toward the time of which they have been participating for a long time and as they tire, those [periods] have been identified as common times when injuries occur. We need to develop a better understanding for how to target those times to prevent injury,” he said.

Parents, coaches and athletes need to learn about overuse injuries and work on the prevention of these injuries by playing multiple sports and cross-training, Cain said.

“As a society, we have to make kids and parents realize it is unlikely you are going to take a 10-year-old and make him, through travel baseball, into a Major League Baseball player,” he said. “Only certain people have that talent and ability. What kids need is development time, without overuse, and free play time. They need time to get out and play in the yard and do the things kids used to do rather than have all specialization where they have too much instruction [and] too much stress on the joints.” – by Casey Tingle

  • For more information:
  • E. Lyle Cain Jr., MD, can be reached at Andrews Sports Medicine and Orthopaedic Center, 805 St. Vincent’s Dr., Suite 100, Birmingham, AL 35205; email: ron.rickel@andrewscenters.com.
  • Peter N. Chalmers, MD, can be reached at Washington University, 1 Brookings Dr., St. Louis, MO 63130; email: p.n.chalmers@gmail.com.
  • Shital N. Parikh, MD, can be reached at Cincinnati Children’s Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229; email: shital.parikh@cchmc.org.
  • Matthew V. Smith, MD, MSc, can be reached at Washington University, 1 Brookings Dr., St. Louis, MO 63130; email: smithmv@wudosis.wustl.edu.
  • Lawrence Wells, MD, can be reached at the Children’s Hospital of Philadelphia, 3400 Civic Center Blvd. #5226, Philadelphia, PA 19104; email: moorea1@email.chop.edu.

Disclosures: Parikh is on the committee for the Pediatric Orthopaedic Society of North America. Cain, Chalmers Smith and Wells report no relevant financial disclosures.

Which is most detrimental to youth pitchers: high pitch counts, high velocity pitches or frequently throwing breaking pitches?

Changing research

Previously, the teaching was children throwing curveballs and breaking pitches before they were skeletally mature was bad. However, I think more recent literature has shown high pitch counts and increased pitching volumes play a major role in overuse injuries. A lot of this work has been done by James R. Andrews, MD, and his colleagues at the American Sports Medicine Institute. Their work has shown pitching year-round, pitching for more than one team at a time, and playing pitcher and catcher in the same game are some of the risk factors for shoulder and elbow injuries in youth pitchers.

Our group has collected some interesting unpublished data showing anatomic changes to the elbow, specifically the ulnar collateral ligament, can be detected in asymptomatic youth and adolescent pitchers. Moreover, these changes correlated with increased pitching volumes in the subjects of our cohort. We are not certain if these changes are pathologic or simply an adaptive response to repetitive overhead throwing. Although harder to quantify, other factors, such as decreased strength and flexibility and improper pitching technique that, contribute to overuse injuries as well. I think with future longitudinal studies, we will gain better insight as to how these factors play a role in upper extremity overuse injuries in youth and adolescent pitchers.

Alfred W. Atanda Jr., MD, is the surgical director of the Center for Sports Medicine at Alfred I. DuPont Hospital for Children in Wilmington, Del.
Disclosure: Atanda reports no relevant financial disclosures.

Increasing cumulative stress

Ulnar collateral ligament (UCL) injuries in the overhead throwing athlete have reached epidemic proportions. Nearly one in three Major League Baseball pitchers will undergo reconstructive UCL surgery at some point during their baseball career. Although the cause of this increasing trend has been hotly debated, it comes down to one simple concept: physics.

The UCL is a static ligament providing stability to the elbow during valgus stress. As prior studies have demonstrated, the process of throwing a baseball places significant valgus loads on the elbow near or above the biomechanical failure load of the ligament. Understanding the biomechanical behavior of a ligament structure teaches us operating within this “breaking zone” will increase risk of failure with time.

To generate velocity, a pitcher must create arm speed to impart force from the body to the ball. This is no different than a golfer generating club head speed to increase distance on a drive. Again, if we go back to high school physics, achieving increased velocity requires increased acceleration which translates to increased torque across the elbow.

As volume of throwing increases, so too does cumulative stress on the ligament operating near its failure load. Similarly, as throwing velocity increases, force on the ligament must increase in order to generate the additional arm and ball speed. Simple physics should tell us the more prolonged stress on a ligament and the more force on a ligament, the higher the risk of failure. In my opinion, increasing velocity at younger ages and increased volume of throwing with time likely explainas the increased incidence of UCL injury in baseball.

Nikhil N. Verma, MD, is a professor and director of clinical research in the Department of Orthopedics, section of Sports Medicine at Rush University Medical Center, Midwest Orthopedics at Rush in Chicago.
Disclosure: Verma reports no relevant financial disclosures.