Injury Prevention in Young Athletes: Stop the ACL Tear Epidemic
By: Barbell Logic Team
A longer-term view of sports development should take into consideration both the general physical development of the athlete and the specific competence required to perform well at the sport. In the same way that a player needs to learn the fundamental skills before they become adept, they should also develop their general physical capacity before they can reach the pinnacle of the physical development for their specific sport. Long-term planning for sports looks like a pyramid, you start with a base of the most general qualities that go into the sport and build upon those fundamental aspects the more refined and specific expressions that make up the sport, position, strategy, and tactics that lead to career-long success
Injury Prevention in Youth Sports
Injury is the black dog of competitive sports; locked away and ignored by the naif invulnerability of youth, until proving them susceptible to serious or painful injury, it evolves to an ominous and constant presence from which many young athletes do not recover.
For physical development, social development, and the maturation that comes from hard work and success, kids should play sports. For children, sports are often the first exposure to the relationship between cooperation and competition, like microcosms of society, teaching children how to work for success and understand failure. And, importantly, they can help otherwise sedentary children develop physical acumen, especially when we expose them to a wide range of sports and activities.
For children who continue to play and compete into their teens, sports can offer opportunities for careers and higher education than what may have been otherwise available. With these possibilities, however, the stakes of winning multiply as the child becomes more competitive. Combine with the social pressures that tend to follow competitive sports, many kids (and coaches, and parents) tend to lose sight of the physical development aspect of playing sports and get swallowed into the competitive aspect.
These are not two separate goals. Even for the best players, winning a single game is rarely the best goal. Instead, training, practicing, and competing in a manner that will allow you to win many games (and many championships) is the primary goal of sports. This makes sports development more like training in which the big picture results are pursued through composite efforts, even when those efforts do not yield short-term satisfaction. We’ve all seen young people who will do anything to “win at practice” including harm their own or their team’s prospects for future victories. This often reveals a connection in the child’s mind between performance and self-worth.
In his book “Warrior Girls: Protecting Our Daughters Against the Injury Epidemic in Women’s Sports,” journalist Michael Sokolove writes about the high rate of injury in youth sports, especially ACL injuries and particularly among young women. He highlights the physical and psychological effects of career-altering injuries and discusses certain societal and systemic pressures that tend to lead toward injuries and the potentially devastating emotional aftermath.
Big problems come when, as Mr. Sokolove points out, coaches, parents, and mentors also push children to compete at all costs and ignore the potential physical problems with doing so. When children play, injury possibilities tend to follow them like a well-heeled dog, always present but rarely problematic. When they compete, however, the risk of injury jumps mightily, and more regularly knocks them out of the game. Pushing children physically tends to increase this risk even further, and feeding their connection between victory and self-worth can make the injury occurrence more devastating.
These two aspects are connected. A longer-term view of sports development should take into consideration both the general physical development of the athlete and the specific competence required to perform well at the sport. In the same way that a player needs to learn the fundamental skills before they become adept, they should also develop their general physical capacity before they can reach the pinnacle of the physical development for their specific sport. Long-term planning for sports looks like a pyramid, you start with a base of the most general qualities that go into the sport and build upon those fundamental aspects the more refined and specific expressions that make up the sport, position, strategy, and tactics that lead to career-long success.
Part of the solution to the high rate of injuries among teenage athletes is to recognize that they aren’t fully developed, either physically or as competitors. Some training time needs to be spent on general development. As an example, Sokolove argues in favor of recognizing the relationship of muscle mass and how it varies in different stages of development, and even more so between boys and girls. He argues in favor of strength training as “part of the puzzle” of injury prevention. And against specialization and “11-month” seasons.
Strength Development and ACL Injuries
There is no more general form of physical development than strength training. Especially for children who are old enough to engage a hormonal response from training. While Sokolove doesn’t necessarily value strength training much, he does highlight the prevalence of ACL injuries and a look at the relationship between knee health and safety and strength training, perhaps offering one argument for the link between strength training and injury prevention.
From its construction, we know that the knee is not supposed to move in certain ways. The knee is the largest joint in the human body and is complex in its construction. It is a modified hinge joint, making its primary movements flexion (bending) and extension (opening). The knee also tolerates slight internal and external rotation. It is a synovial joint, meaning that the femur and tibia meet at a cartilaginous joint enclosed in a fibrous capsule and filled with synovial fluid. This allows for non-hinge-like motion, but the knee capsule also contains structures that prevent certain movements. In particular, the ACL (or anterior cruciate ligament) prevents forward movement of the tibia relative to the femur.
Ligaments can store and release energy. They are fibrous structures. When under strain, most of the force first goes into pulling the fibers straight. Little force acts on the joint itself, instead being absorbed and stored in the ligament. Once the fibers are pulled straight, continual strain is first resisted, then may induce microscopic failure and, if great enough, the elastic properties fail and yields to irreversible deformity, as in a complete rupture. ACL injuries occur when the direction and force on the knee overload the ACL’s preventative capacity. 
But the ACL is not alone in keeping the knee stable and functioning properly. The fibrous sheath of the knee joint transmits forces from the muscles surrounding the joint as well, primarily the quadriceps and hamstring muscle groups. Both of these muscle groups cross the knee joint—the quadriceps attaching on the front of the tibia, pulling to extend the knee, the hamstrings attached on the posterior side of the tibia, pulling in the opposite direction to flex the knee. This means that these muscle groups operate together not just to move the joint but to help prevent the types of movement that the joint is not meant to experience. In particular, the hamstrings’ strong contraction operates to prevent the same forward movement of the tiba that the ACL safeguards against. Although typically flawed, studies seem to support the idea that strong hamstrings are a factor in preventing ACL injuries (or at least that weak hamstrings compared to stronger muscles will help do so).
It shouldn’t surprise anyone that training for strength, making you more robust, durable, and capable, will help prevent injuries. The specific mechanism by which strength helps prevent ACL tears may, perhaps, serve as one example of what should be an obvious statement. Strength is the foundation for sports development and injury prevention. And it should be made a priority for young athletes who are still far away from their ultimate potential.
Our last few articles on sports have discussed the importance of strength training on sports performance, the importance of an off-season, and smart in-season strength training. While the risk of injuries is a natural part of competitive sports. The underdevelopment of youth athletes’ physical capacity takes an already substantial risk and increases it unnecessarily. If young people want to excel at sports they need both general physical training-strength development being of primary importance-and competition. Not all injuries are avoidable, but smart management of competitive schedules and smart training can help reduce these risks, prolong playing careers, and make competitive sports an overall better experience.
 Michael Sokolove, “Warrior Girls: Protecting Our Daughters Against the Injury Epidemic in Women’s Sports” (Simon & Schuster 2008)
 Myer, Ford, Foss, Liu, Nick, Hewett, “The Relationship of Hamstrings and Quadriceps Strength
to Anterior Cruciate Ligament Injury in Female Athletes,” (Clinical Journal of Sport Medicine: January 2009) Vol. 19, Issue 1, pp. 3-8 (http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.624.950&rep=rep1&type=pdf)
 Gabriella Boston, “Protecting ‘warrior girls’” (The Washington Times) (https://www.washingtontimes.com/news/2008/sep/07/protecting-warrior-girls/)
 Jonathon Sullivan MD, PhD, SSC, “Strength and Joint Health,” (from the 2018 Starting Strength Coaches Association Conference) (https://startingstrength.com/video/strength-and-joint-health-part-1).