What's your take on what age young athletes should start lifting weights? I am working with a group of 11 and 12 year-old baseball players doing mostly speed and agility work because their parents are terrified of strength training.
Lets take a look at how kids unfold. As children grow in size and develop muscle mass, they also develop increased strength. These strength improvements are independent of any training stimulus. Children will grow bigger and stronger until full maturity. Boys will naturally continue to get stronger as girls will begin to plateau. This comes from a flood of testosterone that takes place during puberty.
We know one way to increase strength is to increase the diameter of a muscle. Theoretically, a larger muscle will be able to support more weight. Another way to increase strength is through training the central nervous system. These strength improvements are independent of training. Children will grow bigger and stronger until reaching full maturity. Boys and girls diverge as they hit puberty when high levels of testosterone flood the male system and account for extra upper-body bone growth and muscular hypertrophy.
Natural strength development comes in two forms: increased muscle mass and maturing of the nervous system. Since we concluded that a bigger muscle can support more weight, breaking down the muscle and forcing the muscle to adapt to the new stimulus will cause the muscle to grow. Maturing of the nervous system comes in the form of major changes occuring throughout childhood is the myelination of the nerve fibres. Myelination, for those you that have not had the pleasure of hearing Raphael Ruiz speak, is the 'insulation' of the fibres to allow faster conductivity of the electrical impulse. Full myelination happens in adolescence, generally taking 10 or 12 years before even a general development is complete.
“Not all the natural development of strength is due to gains in muscle bulk. Strength also improves because of maturation of the neural systems. One of the major changes that occurs throughout childhood is the myelination of the nerve fibres. Myelination, in lay terms, is the 'insulation' of the fibres to allow faster conductivity of the electrical impulse. Full myelination is completed in adolescence, and so until then coordination and reactions will be limited. There is some evidence to suggest that muscular recruitment also improves with age; adults are able to recruit more motor units when performing maximum efforts, compared to children. In addition, the coordination of synergistic and antagonistic muscles develops with age.”
Since we know that puberty and age will increase strength and size, the question becomes, can make a more dramatic effect with strength training at a young age? Then we get into a bigger can of worms with…at what age should you start strength training? What constitutes “strength” training and more importantly what should that training look like?
I was pointed to an interesting article called “Strength Training by Children and Adolescents” published in Pediatrics. The article states, “In addition to the obvious goal of getting stronger, strength-trainingprograms may be undertaken to try to improve sports performanceand prevent injuries, rehabilitate injuries, and/or enhancelong-term health.”
“Similar to other physical activity, strengthtraining has been shown to have a beneficial effect on severalmeasurable health indices, such as cardiovascular fitness, bodycomposition, bone mineral density, blood lipid profiles, andmental health.”
“Multiple studies have shown that strength training, with propertechnique and strict supervision, can increased strength in preadolescentsand adolescents…In preadolescents, proper resistance training can enhance strengthwithout concomitant muscle hypertrophy. Such gains in strengthcan be attributed to a neurologic mechanism whereby training increases the number of motor neurons that are ‘recruited’ tofire with each muscle contraction. This mechanismaccounts for the increase in strength in populations with lowandrogen concentrations, including female individuals and preadolescent boys. In contrast, strength training augments the muscle growththat normally occurs with puberty in boys and girls by actualmuscle hypertrophy.”
Most importantly, “Appropriate strength-training programs have no apparent adverseeffect on linear growth, growth plates, or the cardiovascularsystem.”
I have few thoughts concerning adolescents and strength training. A few months ago I got a call from a friend who was on location in Bulgaria filming the Conan the Barbarian remake. For those of you who are MMA fans, will know the name Bob Sapp. He had gone to a local junior school for an appearance and was blown away by what he saw. The kids were training in a large gymnasium with a 400-meter track and kettlebells. Many were Olympic weightlifting and practicing gymnastics. He asked me if CrossFit had made its way to Bulgaria as the training he saw looked like many of the CF videos he had seen on YouTube. I informed him…GPP training was first theorized by the Russians 50 years ago and the workouts he saw were the practical application of a general physical fitness program implemented during the cold war.
On a separate occasion, I was relayed some information by a friend who had trained with Angel Spassov. Just for some reference, Angel spent 25 years as Professor of Strength & Conditioning at the Bulgarian National Sports Academy in Sofia, Bulgaria. Angel had told me friend they used the vertical jump as way to assess adolescents that had athletic potential. The ability to generate force at young age (displayed by a vertical jump), before strength training had entered the equation, was a solid way to assess the most genetically gifted. Angel was credited with saying, “Who wants to be normal? Who wants normal results? We want to be exceptional. Exceptions confirm what is not normal".
Another bit of information coming out of the eastern bloc of old, pertains to a study involving prepubescent kids. One group was exposed to strength training before puberty and others were not. Then at the age of 13-14 all the subjects were put into a general strength-training program. On average, the group that had been exposed to strength training gained muscle and strength at a greater rate then the non-exposed group. They theorized there was a “priming of the pump” effect within the muscles and nervous system in the kids that had been exposed to physical training. The gains can be attributed to the hormones released during puberty; the body is flooded with testosterone and those kids that had the “priming of the pump” effect made greater physical advances, as there body was more able to utilize/maximize the hormone release.
So now this begs the questions...what should the training look like in pre-puberty?
In the prepubescent stage boys and girls have similar strength, and at this age children are working on developing their neuromuscular systems. Strength training for kids should consist of skills, cooridnation, stablity, movement, agility, kinesthetic awareness, flexibility and balance. This should include big muscle groups the utilize body weight movements and free weights with light manageable loads. Things like Olympic weightlifting, gymnastics and plyometric movements. If these exercises and movement patterns are taught at a young the athlete will have a greater advantage in technique as they progress in age and strength. On a side note, strength training in youngsters has been shown to promote increased bone mineral density. The gymnastics movements teach strength in the trunk, shoulders and limbs that is not found anywhere else. Plyometric movements have great carry over to speed, aid in the Olympic movements and vice versa.
We have already established that boys will benefit from the rush of testosterone and strength training will result in acceleration of strength and hypertrophy. The gains and progress that can be made in size and strength at this age are like no other. Taking the basic novice program in Starting Strength, and utilized in CrossFit Football, will result in gains that will create a foundation of strength and muscle that will last a lifetime. Since the young male athlete has already laid a solid foundation of skills and movements in pre-pubescent training, he can progress into adult like training and make great gains.
What about the girls?
Girls do not have the benefit of a massive testosterone rush to account for strength gains. As a result, girls will need to compensate for this disadvantage by prioritizing strength training from puberty going forward. If not, strength will level out and decrease over time. Girls naturally do not have the upper body strength associated with males and will need to give this extra attention in their training. If girls do not continue to train, a decrease in their maximal strength will be a limiting factor in athletic performance. However, many will argue that women lifting weights will result in bulky muscles, however, the likelihood of this happening is small. Without sufficient caloric excess and a training program specially designed to create hypertrophy, woman will not build muscles like men. Look how many skinny guys you see at they gym that can’t gain a pound of muscle to save their lives and yet their body produces testosterone. Is it safe say that a women not producing a significant amount of testosterone will not magically develop "Incredible Hulk" like muscles by doing some squats.
“When deciding when to start and progress weight training, it is best to use biological and not chronological age as your guideline; otherwise, certain individuals may be starting too late or too early for optimum development.”