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11 Researched Answers on Strength Training for Kids

Strength Training for Kids Bicep Curls
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Should my child participate in strength training?  Is it safe for him or her to lift weights? Will my child bulk up? What about those growth plates?

These are shared parental questions and concerns when it comes to strength training for kids.  It is a common misconception that weight lifting should be reserved only for adults.   We have been told that kids could get hurt or somehow have their growth affected negatively.  We feel comfortable putting our little ones in sports at very young ages but when it comes to “working out”, the gym setting seems mostly reserved for adults.

Thankfully, this mindset is shifting.  Over the past 20+ years, a large collection of studies have been done on this very topic.  In fact four recent reviews of these studies have proven that strength training is not only safe for our kids, but has significant benefits.

Reviews of Studies on the Impact Resistance and Plyometric Training has on Children
Title Strength Training in Children and Adolescents:  Raising the Bar for Young Athletes? Effects and Dose-Response Relationships of Resistance Training on Physical Performance in Youth Athletes Effects of Aerobic Resistance, and Combined Exercise Training on Insulin Resistance Markers in Overweight and Obese Children Plyometric Exercise and Bone Health in Children and Adolescents
Year of Publication 2009 2016 2016 2017
Type of Research Review Study Systematic Review and Meta-Analysis Systematic Review and Meta-Analysis Systematic Review
Date Range of Studies Included in the Research 1980 – 2008 1985 – 2015 2004 – 2014 1992 – 2014
Number of Studies Included in the Research 45 43 17 26
Age of Study Participants Under 18 years old 6-18 years old 7-19 years old Under 18 years old
Number of Youth in the Studies Didn’t Specify 1558 961 Didn’t Specify


This news is becoming more mainstream and we are witnessing kids strength training programs pop up throughout the country.  However, as parents and kids, we are still left with several questions as to exactly how and what should I or my child do specifically?  Should kids strength train the same as adults?  Should we expect the same results?  Here are some answers to your questions, all based on current research and recommendations.

How many times per week should I train?

2-3x/wk with at least a day of rest in between. It is important that there is adequate rest between sessions as this is the time that the muscles recover.  Make sure to evenly space out your workouts in a week so that you do not go more than 3 days in a row without training.  For example, Monday and Thursday or Tuesday and Friday.  (You may start to lose gains you made if you go longer than 3 days without resistance training.)  If you would like to strength train more frequently, you could consider a split routine in which you train different muscle groups on different days.  For example, lower body Monday and Thursday and upper body Tuesday and Friday.

How many reps and sets should I do?

Depends on your level of fitness, your experience, what type of training you are doing and your goal.  If you are just starting out, it is crucial that you have been taught proper form and that you are able to maintain that form throughout each rep and set.  It is recommended that a beginner starts out with lower weights and higher repetitions.  When you feel comfortable with the exercise, research recommends the following guidelines based on your training type and goals.

Conventional resistance training (Machines, free weights, functional training)

If you want to improve your muscle strength:  6-8 reps for 5 sets

If you want to improve your vertical jump performance: 6-8 reps for 3 sets

This information is what the research suggests. However, to be practical and less confusing, I would suggest that you perform 6-8 reps for 5 sets. You can then gain the benefits of both improved muscle strength and vertical jump performance.  Just be sure that you are challenging yourself for those 6-8 reps but are still able to maintain good form throughout all the sets.  Always consider modifying the amount of resistance in order to ensure good form.

Plyometric training (jump training)

3-5 or 9-12 reps for 4 sets.  Select the number of reps based on the amount you can perform with good quality movement as this is more important than the volume of reps you do.  Why plyometrics?  larger effects on muscle strength, linear sprint performance and sport-specific performance.

How long should I rest b/t sets?  

1-4 minutes. The length of your rest period is based on how challenged you were with the previous exercise and your overall goal.  Basically, rest long enough so that you can maintain good form, especially while progressing weight and/or reps.  The heavier the load, the longer the rest. Your muscles need this recovery period in order to be ready for the next set so that you can continue to perform it safely and with good quality.

How much weight should I lift?

80-90% of 1 max rep (1RM) is ideal. However, American Academy of Pediatrics does not recommend single max lifts until skeletal maturity is reached.  In addition, determination of 1RM should be reserved for the intermediate to advanced athlete who has access to a strength and conditioning professional to guide them through this.  For everyone else, when learning something new, start with no load to ensure proper form. Then begin to add weight each session. If quality of form declines as weight is added, attempt to lift 80-90% of the highest weight you can lift before your form changes. Another way to gauge your intensity is to use a rate of perceived exertion scale.  You should aim for 5-7.

Do I need to strength train all year?  

Maybe.  But this depends on your other activities.  Some studies suggest that you can improve your strength by 30-50% in just 8-12 weeks yet others state that you need at least 23 weeks to see measurable improvement in muscle strength and agility.  If you want your vertical jump to improve, it doesn’t take as long, 9-12 weeks.  When you stop strength training, you can lose an average of 3% per week and may even show complete loss of any strength you gained after 8 weeks.  However, if you are in season and your sport has similar physical demands as your weight training program, you can reduce the time spent on weight training.  That is the tricky part though, not all sport practices and demands are the same.  It is reasonable to suggest that resistance training can be reduced to 1x/wk during an average 6-8 week season as this will allow you to maintain the majority of your training benefits with minimal loss.

How old do I have to be to start strength training?  

There is no minimal age, however, you need to be able to follow directions and have good overall balance and control.  It is usually around the age of 7-8 when kids are capable of this.  The key to staying safe and avoiding injury is to use good technique, the correct amount of resistance and understanding of how to properly use the equipment. This requires adult supervision and good listening skills.

What type of resistive exercise should I do?  

Free weights are best.  They are the most effective to enhance muscular strength and agility because they allow your body to move in full range of motion which better mimics sport specific movements.  However, they require good body control, form and awareness of your posture while using them.  This is where adult supervision is crucial. If you are unsupervised, weight machines are better.  The negative with the machines is they are not one size fits all.  They are built for adults and often do not fit younger children very well. They also can restrict your range of motion.  Functional and complex training, that primarily uses your body as resistance, has been shown to be most effective to enhance sport specific performance. This type of training can mean different things to different people, therefore, it needs a more accurate study to confirm its effectiveness.

What exercises should I do?

Perform 6-8 exercises per training session that target the major muscle groups throughout your body (chest, shoulders, arms, back, legs and abdomen).  Select 2-3 exercises per muscle group and be sure to vary it up each session.  It is very important that you balance the front and back of your body as well as your upper and lower half.  You should avoid power lifting and body building until you have reached skeletal maturity (Tanner stage 5).

What about my growth plates?

Growth plate injuries are rare with weight training.  When they happen, it is related to miss using the equipment, lifting inappropriate weight, rapid progression of weight, using improper technique or uncontrolled movements or training without adult supervision.

Will I bulk up?

This will depend on which stage of development you are in, how much circulating hormones you have in your body and whether you are female or male.  Preadolescents are less likely to gain muscle bulk.  They can certainly gain strength but this is more related to improved neural factors such as more efficient and effective muscular firing and synchronicity. Muscle hypertrophy (bulk) gains can not be completely ruled out for our preadolescents but additional studies need to be conducted.  During and after puberty, the development of muscle tone/bulk is more likely to occur but this may be more attributed to changes in hormones vs the strength training itself.  Adolescent boys generally gain greater cross-sectional size of muscle compared to girls.  However, this size doesn’t really matter.  The benefits of strength training remain the same for both sexes.

What are the benefits of strength training for kids?  

Strength training has been proven to be effective in increasing dynamic strength and is safe for growing muscles, bones and growth plates.  It increases bone density, healthy body composition, improved posture and reduces re-occurrence of injury.  It can also improve your self esteem, mental discipline, social skills, lifestyle attitude and school performance.

Do you prefer to see this in an image instead?  Check out my infographic below!  Save it, pin it, share it!  ENJOY!




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