Originally published in Los Angeles Sports & Fitness, November/December 2014.When the recess bell rings, young children run around, playing tag, hopscotch, kickball, or hanging on the monkey bars. Chip Conrad, owner of Bodytribe Fitness, wrote, “Recess is strength, mobility and creativity in action, in demand, in flux.” During these recess games, children learn to move through interactions with other children, the environment, and different tasks. They develop movement literacy. When they play tag, children run, cut, juke, evade, skip, hop, jump, lean, fake, and more in an effort to avoid being tagged or to tag another child. Nobody has to teach these children how to perform these movements. The playground is the teacher, and their learning is bound only by their imagination and willingness to experiment. Despite the immense learning opportunities that occur on the playground, physically and socially, recess often is deemed to be a frivolous activity, and the first activity eliminated when a school needs more time to improve test scores. Not coincidentally, physical inactivity in American youth has become a pressing political and financial issue as health issues and costs are increasingly tied to a lack of physical activity.At the same time that physical inactivity in youth has become a crisis, overuse injuries have been increasing in adolescents, according to the American Academy of Pediatrics (2007). This is the irony of physical activity in youths and adolescents: fewer children are active, but the incidence of injuries is increasing.Early specialization generally is blamed for overuse injuries and emotional burnout, which may lead to children quitting sports and becoming inactive. However, a 2014 position statement by the American Medical Society for Sports Medicine said, “There is concern that early sport specialization may increase rates of overuse injury and sport burnout, but this relationship has yet to be demonstrated.” If early specialization has not been demonstrated to cause the overuse injuries and burnout, is there a cause?Rather than early specialization specifically, the cause of overuse injuries and physical inactivity may be a loss of movement variability. In our professionalized world, we have demonized play, and in many schools, eliminated recess and physical education.Generations ago, before the obesity crisis and overuse injuries, children played on their own and participated in physical education. Now, children - those who remain active - engage in sports training. Education is an “expansive goal; it’s aim is to increase the number of potential actions,” whereas training is a “reductionist goal; it’s aim is to refine an exiting action” (Paul, 2011). When 18-year-old Taylor Townsend debuted at the U.S. Open in August, former champion Chris Evert spoke about the great variety in her game, whereas most young players rely on a single skill and have to develop greater variability as they reach higher competitive levels.In many ways, we have trained athleticism and fun out of youth sports. Rather than recess and physical education classes, which enabled and encouraged exploration and freedom of movement, we train very narrow skills and discourage variation from the perfect techniques. This emphasis on the perfect rather than exploration turns off some children, and may predispose others to injuries. Rather than play tag with neighborhood children after school, children train their change-of-direction techniques in specialized gyms with professional strength and conditioning coaches. Rather than cut, juke, evade, skip, hop, jump, lean, and fake, children perform repetition after repetition of the 5-10-5 shuttle run.Recess games like tag, dodgeball, or kickball are an example of Bernstein’s (1967) “repetition without repetition.” In a game of tag, children repeat the same cutting, evading, and juking movements multiple times, but none is the same. Every action is based on the interactions with other children, the task, and the environment. Every time that a child evades the child who is "it", the actions that he or she repeats vary. This variation in movement establishes a broader movement vocabulary, just as Evert suggested that Townsend has a greater variety of shots available for her to use on the tennis court. These recess games are educational because they increase the number of potential actions available to each child, and they are fun because the children are in control.Instead of variation, training environments aim to perfect a single technique. The coaches believe that an ideal technique is the appropriate one for success in the skill or sport, and the children must practice this technique. Rather than repetition without repetition, coaches aim for repetition without variation. Coaches critique and instruct when there is deviation. The adults control the activity.One of the primary overuse injuries is elbow injuries suffered by young baseball players, and especially pitchers. Tommy John surgeries, once the domain of Major League Baseball pitchers, are becoming frequent with adolescents. Too many pitches, too many innings, fatigue, and too much velocity are considered to be the main culprits. However, pitching coach Alan Jaeger has suggested an alternate view: insufficient variation.Jaeger wrote in an article titled, “The origin of throwing programs + mechanical myth + post-rehab throwing advice” that the need for perfect mechanics has limited pitchers to throwing 120 feet or less, as anything longer than 120 feet requires something other than perfect mechanics. Glenn Fleisig, research director of the American Sports Medicine Institute, said in a Washington Post article, “We’ve been operating on the theory that [maximizing performance and maximizing safety] go hand in hand. You optimize performance and you stay [healthy]. Now there is concern that optimizing performance comes with increased injury risk.”Jaeger argued that long toss is the missing ingredient to a pitcher’s health. To throw the ball 300 feet, one must arc the ball, and the training view says that this is not specific to pitching. Jaeger wrote, “When you are free to throw the ball with some air under it, you are allowing the shoulder muscles to open up and stretch out at different angles, slowly and progressively. Linear throwing targets a much narrower area, and doesn’t position the arm to gain full range of motion.” Jaeger’s argument aligns with Bernstein’s repetition without repetition; the pitchers throw a lot, but there is great variation between throws. The training viewpoint decreases the variation, but this may unintentionally increase the risk of injury by narrowing and limiting the potential options. Variation may reduce injuries by strengthening the arm through long toss or by reducing the repetitions in the narrow range of motion.In roughly a generation, we have managed to reduce physical activity in children and increase the incidence of injury. Whereas there are many explanations, the primary culprits are the demonizing of recess and playful activities and the decreased emphasis on physical education. These fun games and learning experiences have been replaced by training for sports, and the training has done a lousy job replacing the fun of the games and the expansive nature of the education. Rather than developing a broad foundation of movement skills, we have trained athleticism out of our children, and this leads to children leaving sports and physical activity because the training is not fun or they are not good enough, or to injury from the repetitive nature of the narrow movements and perfect technique. Early specialization is a worry, but it is part of the problem, and not the cause. The cause is our departure from play. As Conrad wrote, “A switch is flipped, sometime in our lives, where movement turns from joy to obligation, from recess to a workout.” He was writing to adults; unfortunately, this switch increasingly is flipped in childhood or adolescence.By Brian McCormick, PhDDirector of Coaching, Playmakers Basketball Development LeagueAuthor, The 21st Century Basketball Practice