Someone in class tenth asked me today that whether doing push ups stunts height because that's what his school teacher who has a PH.D. told him.
I told him that I would search on this and then share the same with him.
From http://kidshealth.org/parent/nutrition_center/staying_fit/strength_training.html
Age Guidelines
Generally, if your child is ready to participate in organized sports or activities such as baseball, soccer, or gymnastics, it is usually safe to start strength training.
A child's strength-training program shouldn't just be a scaled-down version of an adult's weight training regimen. A trainer who has experience in working with kids should design a program for your child and show your child the proper techniques, safety precautions, and how to properly use the equipment.
Kids as young as 7 or 8 years old can usually do strength-training activities (such as pushups and sit-ups) as long as they show some interest, can perform the exercises safely, and follow instructions. These exercises can help kids build a sense of balance, control, and awareness of their bodies.
Specific exercises should be learned without resistance. When proper techinique is mastered, small amounts of resistance (body weight, band, or weight) can be added. In general as kids get older and stronger, they can gradually increase the amount of resistance they use. A trained professional can help your child determine what the appropriate weight may be.
About Strength Training
Strength training is the practice of using free weights, weight machines, and rubber resistance bands, or body weight to build muscles. With resistance the muscles have to work harder to move. When the muscles work harder, they grow stronger and more efficient.
Strength training can also help fortify the ligaments and tendons that support the muscles and bones and improve bone density, which is the amount of calcium and minerals in the bone. And the benefits may go beyond physical health. Young athletes may feel better about themselves as they get stronger.
The goal of strength training is not to bulk up. It should not be confused with weight lifting, bodybuilding, and powerlifting, which are not recommended for kids and teens. In these sports, people train with very heavy weights and participate in modeling and lifting competitions. Kids and teens who do those sports can risk injuring their growing bones, muscles, and joints.
From http://www.hss.edu/conditions_strength-conditioning-kids.asp
In the right environment, and with proper supervision and technique, strength training for kids has been deemed safe and effective for kids and has been approved by the American College of Sports Medicine, the American Academy of Pediatrics, the American Society of Sports Medicine, and the National Strength and Conditioning Association.
It is thought that strength increase in children who participate in strength training involves changes in the muscle that already exists. A muscle works by nerve firing, and strength training in children and adolescents changes the way the nerves fire, such that more muscle fibers are activated by each nerve. This increases muscle strength in children without changing the composition of the actual muscle.
Contrary to prior understanding, new studies have shown that growth plates (the areas of primary growth at the ends of longer bones) in prepubescent children are not at high risk of epiphyseal fractures when the training adheres to these guidelines. Strength and conditioning training can actually enhance bone growth; the greatest amount of bone formation occurs during childhood, and strength training can serve to create stronger bones if done correctly and in the proper setting.
Is Strength Training Effective for Kids?
Studies: Then and Now
We now have a better understanding of the neurology behind muscle hypertrophy, and strength training in general, than was common 25-30 years ago. Studies done in the 1970s and 1980s which debunked the validity of strength training were later denounced by the American Academy of Pediatrics for using inaccurate parameters and excluding important studies on natural strength gained by children. For example, in the 1970’s, researchers didn’t realize that it took six weeks for the motor units to change in number and size.
Contemporary studies have altered that approach and have determined that children as young as six years old “can improve strength when following age-specific resistance training guidelines.”
(Benjamin, Holly J. MD; Glow, Kimberly M. MD, MPH, Strength training for children and adolescents. The Physician and Sports Medicine. 2003, Sept; (31)9)
Two studies used the twitch interpolation technique to determine the effects of changes in motor unit activation on strength increases in preadolescent boys when in a proper training environment. This technique involves delivering single electrical pulses to a muscle when the subject is at rest and while the subject attempts to produce a maximum voluntary contraction. The training sessions lasted ten weeks; when it was over, they saw a gain of 9% in the boys’ elbow flexors and 12% in their knee extensors. Strength gains were due to increased neuronal activation, intrinsic muscular adaptations, and motor coordination (learning). While muscle strength increased, the size of the muscle did not.
(Ramsay JA, Blimkie CJ, Sale DF, et al.. Strength training effects in prepubescent boys. Medicine & Science in Sports & Exercise. 1990; 22(5):605-614)
Movement Intelligence
An instinctual factor in sports, called “movement intelligence”, has also been shown to increase after a course of strength and conditioning training. Movement intelligence is when all the parts of the body learn to coordinate movement together in the most effective way. With proper training, this state is achieved with no conscious thought, e.g., when a basketball player jumps up for a rebound or when a baseball player swings at a pitch. The muscles involved with these movements and responses become more inherently and instinctually conditioned to react quickly and properly, resulting in increased ability and a reduced risk of injury. Since movement intelligence is learned, and since children tend to learn quickly at an early age, it is best to teach it as early as possible.
(Ramsay JA, Blimkie CJ, Sale DF, et al.. Strength training effects in prepubescent boys. Medicine & Science in Sports & Exercise. 1990; 22(5):605-614)
Strength and conditioning training for children can be safe and effective when proper safety guidelines are met and each child’s program is designed appropriately and individually. A pre-training evaluation by a personal trainer is necessary, along with a post-training evaluation, and the child must be supervised throughout the course of the training by the trainer. Likewise, the child’s parents must take an active interest in the regimen without resorting to forceful excess. The quality of each training session should be stressed over the quantity of sessions, and when applicable, the training should be as sport-specific as possible. Most importantly, a child undergoing strength and conditioning training should never stop having fun doing it.
