June 24, 2026, 8:28 am | Read time: 9 minutes
Sometimes you have to rub your eyes in disbelief: Are there really weightlifting championships and Hyrox competitions for kids? Sure, sport is healthy—and that’s especially true for kids. They need physical activity to properly develop muscles, bones, coordination, the cardiovascular system, and even self-confidence. But what happens when play turns into training? When a child no longer just runs, climbs, or dances, but trains intensely four, five, or six times a week, possibly influenced by social media role models or the desire for a certain body image? FITBOOK discussed this with Prof. Jannos Siaplaouras, a pediatric cardiologist and president of the Society for Pediatric Sports Medicine (GPS).
First of All: Kids Generally Don’t Move Enough
Before discussing “too much sport,” Prof. Siaplaouras emphasizes that the bigger issue is often the opposite. The World Health Organization (WHO) recommends that children and adolescents aged 5 to 17 engage in at least 60 minutes of moderate to intense physical activity daily. At least three days a week, this should include more strenuous activities and exercises for muscles and bones.1
Siaplaouras states clearly: “Physical activity is essential for children. Without regular movement, muscles, bones, the cardiovascular system, and motor skills do not develop optimally, and physical activity also plays a crucial role in mental and social development.”
But many children do not meet this activity goal. Siaplaouras points to the KiGGS study by the Robert Koch Institute.2 According to the study, only 26 percent of 3- to 17-year-olds in Germany achieve these 60 minutes of daily physical activity. Additionally, Siaplaouras notes that “especially chronically ill children are overly protected—and we have about 15 percent chronically ill children in Germany. They could participate much more in physical activities.” Children with mild heart defects often have no physical limitations but are less active, perhaps because parents or teachers have concerns or because they have had negative experiences in school sports. Siaplaouras advises against being overly cautious: “Often, the prognosis for these children worsens if they do not get enough exercise.”
Movement or Sport–What’s the Difference?
For children, movement and sport are not always easily separated. Playing, running, climbing, cycling, dancing: Much of it happens playfully, just in everyday life. Siaplaouras describes the difference as follows: Sport is more goal-oriented, associated with performance acquisition or competition. Movement is freer and less structured. Children also move differently than adults: “They run and then stop, run and stop again.” They often do not train in the true sense but use what their bodies can currently do. That’s why it’s important not to question every intense movement immediately. A child who enjoys ballet, soccer, climbing, swimming, or strength training is not automatically doing “too much.” It becomes critical when training, pressure, and lack of recovery come together.
Problems Children Can Face from Too Much Sport
High Performance, Little Recovery
“The same principle applies to children and adults,” explains Siaplaouras, “namely the principle of stress and recovery. Training should challenge the body. Afterward, it needs rest.” During this recovery phase, the body adapts and can perform better later.
To achieve this, it’s important to distinguish between “functional overreaching” and overtraining syndrome, explains the pediatrician. Functional overreaching is deliberately used in competitive sports: The body is more heavily challenged for a short time, and performance may temporarily decrease. But then recovery is essential, and the body can regain strength. “Then the desired adaptation processes occur, leading to improved performance,” Siaplaouras explains.
Overtraining syndrome threatens when the body is permanently overloaded. “If you train but don’t recover, you can’t recuperate, and your performance continues to decline,” says Siaplaouras. The body is not just “tired,” but performance decreases over weeks to months and doesn’t improve as quickly. The consequences: persistent fatigue, sleep problems, decreased performance, mood swings, frequent infections, pain, injuries, or lack of motivation to train.3 “Recovery is just as important as physical activity,” recommends Siaplaouras.
RED-S: Lots of Activity, Little Eating
It also becomes problematic when children and adolescents expend a lot of energy through training, growth, school, and daily life, but do not consume enough energy. In sports medicine, this is called “Relative Energy Deficiency,” or RED-S. RED-S results in an energy deficit that affects not only weight and performance but also many body systems: hormones, bones, immune system, metabolism, and psyche. The International Olympic Committee has also described the problem.4
RED-S can occur because training is very demanding. But sometimes it can also be intentional: It is particularly tricky when children train a lot during a growth phase and are also expected to stay slim. This creates a goal conflict “that is actually difficult to resolve.” Siaplaouras emphasizes: “A child who trains a lot must also eat enough.”
Extremely Intense Training
Is there “too much sport” for children and adolescents? For organized training sessions, the rule of thumb often cited is the child’s age in hours per week, but Siaplaouras finds this only partially suitable. “For example, a 15-year-old might interpret this as 15 hours of intense training per week—which is not correct,” the expert emphasizes. He advises considering “very individually” how much physical stress a child can actually handle and how much recovery they need, depending on personal development and psychological situation.
For Siaplaouras, three points are important for reliable recovery:
- Children need one to two days a week without organized sports.
- Additionally, there should be one to three months annually without competitive events to allow for adequate physical and mental recovery.
- And parents should respond if fatigue, insomnia, performance decline, frequent infections, or psychological issues arise. Then it should be checked whether there is a nutritional deficit—such as insufficient energy intake or low iron stores—or if the child is not getting enough rest.
An immediate stop to sports is recommended by the Professional Association of Pediatricians and Adolescent Doctors in case of pain: The sports program should be paused until examinations determine the cause.5
When Fun Suddenly Becomes Compulsion
But not only physical limits are important in the sports routine for children and adolescents—psychological ones are too. A spot on the podium is, of course, a nice achievement, as is a medal or a great victory photo. But when trophies, rankings, and social media posts become too important, the fun in sports can turn into the opposite. Then children might train primarily for recognition, to meet expectations, or to conform to a certain ideal. “Excessive expectations from parents, coaches, or social media can lead to psychological stress, loss of motivation, and burnout symptoms,” warns Siaplaouras, suggesting that “the child’s own joy in movement should always be the focus during childhood and adolescence.”
Why Children Should Balance, Hop, and Climb–and How to Encourage It
When should children start doing sports – and how do they find the right one for them?
Are Some Sports More Problematic for Kids Than Others?
Lucy Milgrim from the U.S. is an internet sensation. The 10-year-old can deadlift nearly 90 kilograms. But: Is that still healthy, or are sports like weightlifting unsuitable for children? Siaplaouras warns against simple rankings. There is no one sport that is always good or always bad: “Children should first be allowed to do the sport they enjoy.” Strength training is not off-limits for children either. The concern that strength training could stunt growth is outdated. “Resistance training for children and adolescents can be safe and beneficial if it is age-appropriate and well-guided,” says Siaplaouras. It can improve fitness, muscle strength, motor skills, and injury prevention.6
However, in strength training for children and adolescents, the focus should not be on maximum performance but on technical competence, movement control, and diverse development, emphasizes an international research group.7
Why Ballet and Gymnastics Can Be Challenging
Nevertheless, there are sports with particular risks. Especially when they require high training volumes, many competitions, or a specific appearance. Siaplaouras explicitly mentions ballet and gymnastics as areas where it can become problematic because stress, body ideals, and performance pressure quickly converge.
Children Should Engage in Diverse Sports
The pediatric cardiologist also advises against early specialization. He recommends that children and adolescents participate in multiple sports rather than focusing on one sport with high intensity too early.
This aligns with international recommendations: The WHO also emphasizes that activities for children should be varied, age-appropriate, and, above all, fun. When children run, kick, balance, and climb, they develop various motor skills, avoid one-sided stress, and stay motivated longer. Even if they want to pursue elite sports later, there is no reason, according to Siaplaouras, to specialize too early. His judgment is supported by research findings. Apparently, specialization after puberty is sufficient.8 In some cases, the risk of injury even increases if children specialize too early and too narrowly in one sport.9
Tips for Parents
Parents, teachers, and coaches can find information on the requirements and risks associated with various sports on the website of the Society for Pediatric Sports Medicine. There, typical requirements, injuries, overuse consequences, contraindications, and preventive measures for many sports are described. For weightlifting, the Society emphasizes the importance of excellent technical training and general athletic education. In rhythmic gymnastics, stress on the feet, knees, and lumbar spine, as well as a risk of eating disorders, is mentioned. These profiles can help assess a child’s sport more accurately—not based on gut feeling, but on typical stresses and sensible protective measures.
Warning Signs: When Parents Should Be Alert
Parents don’t need to hold back a sports-loving child just because they are ambitious, says Siaplaouras. What matters is whether the child remains healthy and trains of their own accord. It’s different if the child drags themselves to training, is constantly tired, performance stagnates, weight development becomes noticeable, or physical complaints arise: sleep disturbances, susceptibility to infections, and psychological changes are warning signs. “If there is a long-term imbalance between stress and recovery, then it’s a sign that it’s better to scale back,” says Siaplaouras.
The best guideline is not the question “How much is still allowed?” but: Is my child doing well? Are they happy? Do they get enough sleep and eat enough? Do they still have time for school, friends, and play? Are there sports-free days and phases without competitive pressure? Does the child do sports because they want to, or are parents, clubs, coaches, or social media the real driving force?
Parents should also regularly consult with coaches to discuss how the child is doing in sports and whether the training plans are really suitable. In cases of persistent fatigue, pain, performance decline, menstrual irregularities, noticeable weight changes, or psychological stress, a sports break and a visit to a pediatrician or sports doctor are advised. Siaplaouras also points to the offerings of the Society for Pediatric Sports Medicine: They also provide direct contacts to specialists on-site.