5 myths about physical development in youth soccer

Part 3 

This is the third installment of our “Myths” series; feel free to backtrack the first two parts here (Part 1 and Part 2). The first couple of posts have spawned some great conversations, and I think this week will continue with much of the same. Make sure that you leave a comment or question on the website if you have anything that pops in your mind, regarding these topics. Without further delay…

Myth #3 – Soccer players should not strength train. If youth players begin lifting weights too early, they will stunt their growth.

This is one of my favorite conversations that I frequently have with coaches, players, and parents, even though there has been a plethora of research published regarding this very topic.  In this post, I will try to give a short but descriptive account of the origin of this myth, the research behind the debate, and the anatomy behind growth plates.

baby-lifting-weights2

Early strength training “rules” stated that immature adolescents or preadolescents performing resistance-training exercises would close off the epiphyseal plates (aka: growth plates) and stunt growth or create an irregular bone growth that would cause deformity in the limb.

Although the origin of this myth was so long ago, nobody can pinpoint the exact origin, it seemed to gain popularity due to a study in 1964, by Kato & Ishiko (1) that looked at adolescents in Japan and the nature of their heavy labor for long hours, contributing to their short stature. This, in addition to early studies showing no effect from preadolescent and adolescent resistance training (2,3) (due to the low volume and intensity), spawned the notion that any resistance work (including strength training) would have the same effect and disrupt growth patterns. Unfortunately, this extremely outdated thought process still exists with coaches and parents today.

(1)*Kato, S., & Ishiko, T. (1964). Obstructed growth of children’s bones due to excessive labor in remote corners. In S. Kato (Ed.), Proceedings of the International Congress of Sports Sciences (pp. 476). Tokyo: Japanese Union of Sports Sciences.
(2)Vrijens J: Muscle strength development in the pre- and post-pubescent age. Med Sport 1978;11:152-158
(3)Docherty D, Wenger HA, Collis ML, et al: The effects of variable speed resistance training on strength development in prepubertal boys. J Hum Mvmt Stud 1987;13:377-382

weightsContrary to this statement of the myth, there are hundreds of studies that show this argument couldn’t be further from the truth. Fact is: The epiphyses (growth plates), located in the arms and leg bones, may not even close until the late teen years. Therefore the argument of waiting until 14 or 16 (when growth ceases) years old would not be validated due to the continued existence of fragile bone. Secondly, the fractures or pressures that cause the rare issues within the growth plates are created through a huge amount of shear force. Such force is highly unlikely to exist in resistance training, unless the hundreds of pounds lifted actually falls onto the bone with a considerable amount of force, fracturing the point of the bone where epiphyseal construct exists.

 

In fact, it may be much more of a likely incident that growth would be affected by fractures or pressures on the growth plates, due to the nature of injuries during the game (such as ligament tears and joint dislocation). In a course lecture by the doctors that are credited with the foundational research on growth plates, Salter and Harris, they cite that ligament damage and bone separation, from injuries commonly found in soccer play, and are more likely a source of childhood growth plate separation that would cause growth problems. The quote, from this lecture below, could be a further talking point on why we need to prepare players better (through movement quality and strength training) to combat against ligament injuries.

“The explanation for this apparent paradox …(fractures through the bone are much more common that growth plate separation, even though bone is stronger than the cartilage tissue)…probably is that only shearing forces and avulsion forces are capable of separating an epiphysis. The epiphyseal plate is also weaker than normal tendons and ligaments in children. For this reason, injuries that may result in complete tear of a major ligament in the adult actually produce a separation of the epiphysis in the child. For example, an abduction injury of a child’s knee results in epiphyseal separation rather than in rupture of the medial collateral ligament of the knee. Similarly, the epiphyseal plate is not as strong as the fibrous joint capsule. Hence, traumatic dislocation of major joints, such as the shoulder, hip, and knee, are decidedly less common in childhood than epiphyseal separations in these locations. For example, the injury that usually produces an anterior dislocation of the shoulder in an adult is likely to produce separation of the upper humeral epiphysis in a child” (4).

(4) Salter and Harris:Injuries Involving the Epiphyseal Plate. J. Bone Joint Surg. Am., Vol. 45-A, No. 3, April 1963.

Not only is it appropriate for young athletes to strength train, it has strong correlations to preventing injuries, diminishing already existing injuries, and increasing sport performance and health…therefore advised and encouraged. I have listed below some defining research that justifies the following pro-strength training arguments at early ages:

SONY DSCLet me finish by giving an anecdotal example of how strength training may be the best option for many growth related injuries/issues, that were once considered a clear contraindication against strength training. Osgood-Schlatters disease is a common occurrence amongst growing youth soccer players, and is caused by the growing growth plates creating stress on the Pattelar tendon due to the discrepancy in the speed of growth between the bone and soft tissue. The discrepancy causes a pull on the tendon and small fractured bone creating inflammation and calcification below the patella. Doctors and physical therapists regularly recommend stretching the quadriceps and hamstrings, while strengthening the hamstrings and hip stabilizers, in order to relieve stress from the patella. We all know that strength training will activate and strengthen the muscles for relief, but very few know that resistance training causes a definitive increase in flexibility. In fact, the research study, below, shows that specific strength training is even more effective than stretching, in creating flexibility in a given muscle group.

The effects of eccentric training on lower limb flexibility: a systematic review, by O’Sullivan, McAuliffe and DeBurca, in British Journal of Sports Medicine, 2012 

Strength training with appropriate resistance must be intelligently designed for the individual, taking into perspective the following: strength training history, biological age, injury history, movement pattern quality, and sport demands. Although I do not believe that growth will be ultimately affected by ignoring the previous aspects of screening, it is known that the training will definitely not be as effective and could cause other issues that end in injury. I do hope to touch on these individual aspects in future posts, but the fact remains that every soccer athlete must include appropriate strength, at all ages.

John